Baking powder(Suitable for puffed flour products)

Baking powder is a compound additive mainly used in the production of flour products and puffed foods. Baking powder contains a variety of substances, the main components of which are sodium bicarbonate and tartaric acid. Usually a compound of carbonate and solid acid. When carbonates come into contact with water and acids, they break down into a variety of substances. During this process, a high is released, but no flavor is produced. Therefore, the taste of the product is inconvenient.     Fermentation   There are generally three fermentation methods for making fermented dough: old yeast, fresh yeast, and baking powder. Fresh yeast and baking powder are commonly used in households. Pay careful attention to the aluminum content in baking powder. Aluminum content in food exceeding national standards can cause harm to the human body.   Yeast and baking powder both have the function of fermentation, but they are essentially different.   Yeast is a pure biological leavening agent, an active microorganism, which will not cause any harm to the human body; while chemical baking powder is a chemical leavening agent, generally referring to baking soda (sodium bicarbonate), stink powder (ammonium bicarbonate), alum ( Potassium aluminum sulfate or potassium aluminum sulfate, SAS), baking powder (baking powder) and other substances.   Classification   chemical leavening agent   baking powder   1. Baking soda ( sodium bicarbonate ,): Under the action of acidic substances contained in food , baking soda can be decomposed into sodium ions , water and carbon dioxide gas, the latter of which can fluff food. However, the reaction of baking soda to release gas requires the presence of acidic substances and is completed in a very short time. The initiation of the reaction is difficult to control. If the dosage is too large, it will produce a bitter or astringent taste . For these reasons, baking soda is rarely used as a leavening agent alone, and is generally used as one of the components of a compound leavening agent.   2. Stinky powder ( ammonium bicarbonate ): Stinky powder is generally used when a large amount of gas needs to be generated quickly. Stinky powder will decompose into water, ammonia and carbon dioxide gas when heated or under acidic conditions . Due to the rapid release, very little ammonia gas remains in the finished product, and there will be no ammonia smell in the finished product. Since stink powder easily decomposes and releases ammonia gas (this is where the name of stink powder comes from) and loses its effect, it is difficult to store and is generally rarely used in households. Stinky powder is used when baking peach cakes or certain biscuits.   3. Alum (potassium aluminum sulfate or potassium aluminum sulfate, SAS): Commonly used alum is actually an acidic mixture, which releases gas when it interacts with food’s inherent or added ingredients such as baking soda, which has a fluffy effect. It is generally also an acid component used as a compound fluffing agent. The characteristic is that it can react quickly at high temperatures . A common example is for frying fried dough sticks   baking powde   1. Baking powder: It is a compound leavening agent, and there are many different types. Generally, solid alkali and acid powders are mixed . They do not contact or react under dry conditions. Once they come into contact with water, they will dissolve and contact, and the reaction will release gas. Solid alkali powder is commonly used in baking soda, and solid acid powder includes tartar ( tartar) and phosphate (phosphate, such as calcium phosphate and sodium pyrophosphate ). Their reaction speeds are very fast; in addition, alum (SAS) is used. ) as a solid acid, the reaction rate is much slower, but very fast at high temperatures. Alum is commonly found in Double-acting (DA) baking powders. Double effect means that after mixing water and flour, baking soda first reacts with a fast solid acid (such as cream of tartar) to release the first batch of gas. At this time, alum and baking soda basically do not react, but when heated, alum When heated with baking soda, a second batch of gas is released, which is called double-acting. Commonly seen on the market is double active baking powder. Some self-raising flours also have baking powder already mixed into them and need to be baked quickly after adding water. Because baking powder is easy to store and easy to control, it has become the most commonly used leavening agent and is used in most Western-style pastries.   2. Dangers of chemical leavening agents :   Since the reaction products of baking soda and stink powder ( carbon dioxide , ammonia) are also products of human metabolism, as long as they are not used excessively, they will not cause obvious health problems , but they will destroy certain nutrients in food such as vitamins. And both alum and baking powder contain aluminum. Many international reports have pointed out that aluminum is closely related to Alzheimer’s disease . It also reduces memory, suppresses immune function , and hinders nerve conduction . Moreover, aluminum is excreted very slowly from the human body. The amount of alum and baking powder in food should be strictly controlled. Use and try to eat less aluminum-containing foods.   biological leavening agent   Yeast is a unicellular facultative anaerobic eukaryotic microorganism. After being added to the dough, it can produce carbon dioxide gas through its own metabolism to achieve the purpose of fluffiness. This process is often called fermentation. In the past, old noodles were often fermented, mainly relying on wild yeast and some miscellaneous bacteria. Dough usually contains organic acids, which give it a sour taste. Baking soda needs to be added to neutralize the sour taste. Bacterial metabolites and added baking soda may introduce harmful ingredients or destroy nutrients.   The active yeast commonly used in modern times has high purity and rarely produces acidic substances. At the same time, yeast itself is composed of protein and carbohydrates, and is rich in B vitamins and other trace elements such as calcium and iron, and is rich in nutrients. value. Yeast acts as a leavening agent for pasta and requires sufficient time and temperature to produce carbon dioxide.   Obviously, yeast is a beneficial biological leavening agent that has no negative impact on the human body and can provide nutrients and vitamins that humans need but lack. is the most ideal fermentation method. It is essentially different from chemical baking powder. Simply put, yeast is not chemical baking powder!

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Protein Powder

Protein powder, using purified soy protein .   In healthy people, protein deficiency does not occur. Excessive protein intake is not only a waste, but also harmful to human health.     Introduction   Protein is the most important nutrient to ensure the health of the body . It is necessary to maintain and repair the body and cell growth . It not only affects the growth of body tissues such as muscles, but also participates in the production of hormones, the maintenance of immune function, and the use of other nutrients and oxygen. Transport, hemoglobin production, blood coagulation and many other aspects. General mental workers require 0.8-1.0 grams of protein per kilogram of body weight every day, while high-intensity athletes and bodybuilders require 2-3 times that amount. This is because high-intensity exercise will damage muscle cells to varying degrees. , causing the decomposition of muscle protein. Timely supplementation of protein can reduce the destruction of muscle tissue, promote protein synthesis, and even over-recovery, thereby growing muscles and improving strength. The traditional way of supplementing protein by eating meat often leads to the intake of too much fat, causing an increase in body fat and even affecting cardiovascular health.   Children in the growth and development period need a large amount of protein to meet the needs of physical development, and pregnant women need a large amount of protein to produce red blood cells and develop the fetus. However, the traditional supplement method of eating big fish and meat often makes many women still lose weight after giving birth. It cannot be reduced because while they are supplementing protein, they are also supplementing a lot of fat. Patients after surgery and recovering from serious illness also need a large amount of protein to promote recovery and improve immunity.   use   Protein powder is a nutritional food supplement targeted at specific groups of people. As an amino acid supplement, protein powder can provide essential nutrients due to protein deficiency for young children, the elderly, sports people, pre- and post-operative patients and people losing weight.   In addition, people with poor appetite or poor digestion, as well as people who are on a diet to lose weight, and vegetarians may not have enough protein intake. This will not only cause developmental delays in children and affect the body’s water metabolism, but may also lead to low immune function and poor sleep. and anemia and other diseases. In these cases, a high-quality protein powder makes a good supplement.   nutritional value   Participate in the composition of the body and the metabolism of the body   Protein is an important type of nutrient. Its existence is closely related to various activities of life. For example, it participates in the composition and metabolism of the body, participates in the composition and metabolism of genetic information, and also provides heat for the body.   The extent to which they can be digested, absorbed and utilized by the human body is also different.   There are extremely many types of proteins. Proteins from different food sources can be digested, absorbed and utilized by the human body to different extents. In other words, different types of proteins have different nutritional values. The main factor that determines the nutritional value of proteins is protein. Types and contents of essential amino acids . The amino acid score (AAS) is a commonly used indicator to evaluate the types and contents of essential amino acids in proteins .   Healthy people do not need to consume protein powder   The “Reference Intake of Dietary Nutrients for Chinese Residents” recommends that the daily protein intake per adult is 65 to 90 grams, or 10% to 12% of total energy to meet metabolic needs. In addition, protein intake varies depending on a person’s age, weight and labor intensity. Children and adolescents during the growth and development period, as well as pregnant or lactating women, generally have higher protein requirements.   The main function   1. Supplementary nutritional sources   Protein is the main source of nitrogen in the human body . It can not only provide part of the energy consumed, but can also be used to synthesize new tissues. Protein in the adult body accounts for about 17% of body weight, and 3% of protein participates in metabolic renewal every day. Infants , young children, teenagers, pregnant women, and lactating women must not only maintain tissue protein renewal, but also synthesize new tissues. When there is insufficient protein in the body, people’s basic life activities will be affected, which can lead to growth retardation, underweight, and mental retardation in children and adolescents; in adults, fatigue, weight loss, anemia , reduced plasma albumin , and even edema; And can cause menstrual disorders in women. Consuming protein powder can effectively prevent or improve these symptoms.   2. Prevent disease   Heart disease is the number one cause of death in Western developed countries. High plasma cholesterol levels are a major cause of heart disease. Animal fat in the diet can increase plasma cholesterol levels and is an important factor in arteriosclerosis and heart disease. Excess saturated fatty acids , cholesterol , and blood cholesterol are directly related to heart disease. Reducing plasma cholesterol also reduces the risk of heart disease. In 1982, scientists from many countries conducted comparative experiments in Italy and Switzerland on patients with high cholesterol using soy protein to replace animal protein. The results showed that consuming 50 grams of soy protein per day reduced their total plasma cholesterol by 20%. This study proved that soy protein It can reduce the adverse effects of blood lipids and cholesterol on the heart in patients with high cholesterol. In the United States, doctors recommend that heart patients eat soy protein before taking cholesterol-lowering drugs. Because soy protein is neither a drug (no toxic side effects) and cheap, it can effectively prevent heart disease without any side effects.   3. Reduce the burden on the kidneys   Kidney disease is a common long-term complication of diabetes , with more than 20% of diabetic patients suffering from impaired kidney function . Ingesting animal protein will increase the burden on the kidneys, leading to aggravation of the condition. Soy protein can prevent and reduce the damage of animal protein to the kidneys by lowering plasma cholesterol levels. Through observation of the dietary treatment of patients with kidney disease, it is found that replacing animal protein with soy protein has the best effect, and patients with kidney disease are also willing to accept foods containing soy protein.   For people   For special people in need, in addition to supplementing essential amino acids through food, protein powder can be appropriately selected as a protein supplement, but the amount of protein powder must be paid attention to. After protein is digested and absorbed through the gastrointestinal tract, it needs to be processed by the liver and converted into the body’s own substances for use by the body.   At the same time, nitrogen-containing substances such as ammonia, urea , and creatinine , the products of protein metabolism in the body, need to be excreted by the kidneys. If a person eats too much protein, it will increase the burden on the liver and kidneys and have adverse effects on the human body. Therefore, more protein is not always better .   Use with caution   1. Patients with liver disease should use with caution   Due to obstacles in the liver’s processing and utilization of protein, protein intake should be appropriately increased. However, for patients with hepatic coma and advanced cirrhosis, supplying too much protein will increase the burden on the liver and aggravate the condition, so animal protein should be limited . And because its metabolism in the body will produce more ammonia, which can induce or aggravate hepatic coma, so these patients can choose some plant proteins rich in branched chain amino acids , especially soy protein . Because branched-chain amino acids are mainly metabolized in muscles, they have a protective effect on liver function.   2. Children under three years old should not eat it   Newborns should not consume protein powder. The best nutrition for babies is breast milk. If the child cannot eat breast milk due to various reasons, he should choose formula milk powder corresponding to the month or age instead of protein powder, because the protein composition of the latter is not suitable for young children and is not conducive to the child’s digestion and absorption. It is likely to cause vomiting, diarrhea or allergies in the future.   3. Gout patients should choose carefully   Consume protein powder with soy protein as the main ingredient. Because the purine in soybeans can cause an increase in uric acid in the body, causing or exacerbating gout. However, some brands of soy protein powder have undergone special processing to reduce the purine content. 4. Special patients should seek medical advice before consumption. The protein contained in protein powder is of high quality. It is decomposed by the liver in the body and then synthesized into the body’s own tissue components. Its metabolites are excreted in the urine through the kidneys. Patients with existing liver, kidney disease and other serious diseases may increase the burden on their organs after taking protein powder. Therefore, before taking protein powder, you should seek the advice of your doctor before deciding whether to consume it. If you want to increase your protein powder consumption, you should also listen to your doctor’s advice.

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C-Reactive Protein

C-reactive protein (CRP) is a protein (acute protein) that rises sharply in the plasma when the body is infected or tissue damaged. It activates complement and strengthens the phagocytosis of phagocytes to play a regulatory role in clearing the invading body. Pathogenic microorganisms and damaged, necrotic, and apoptotic tissue cells.     definition   C-reactive protein (CRP) refers to some proteins (acute proteins) that rise sharply in the plasma when the body is infected or tissue damaged. CRP can activate complement and strengthen phagocytosis by phagocytes to play a regulatory role, thereby eliminating pathogenic microorganisms that invade the body and damaged, necrotic, and apoptotic tissue cells , and plays an important protective role in the body’s natural immune process.   characteristic   CRP is not only a non-specific inflammatory marker, but also directly involved incardiovascular diseases such as inflammation and atherosclerosis , and is the most powerful predictor and risk factor for cardiovascular diseases. The interaction between CRP and complement C1q and FcTR enables it to exhibit many biological activities, including host defense response to infection, phagocytosis and regulation of inflammatory response, etc. The combination with damaged cells, apoptotic cells and nuclear antigens also plays an important role in autoimmune diseases.   normal value   Which detection method is used depends on the conditions of each laboratory and the requirements for sensitivity and specificity. Immunodiffusion, radioimmunoassay, turbidimetry, and enzyme-labeled immunoassay methods all have practical value.   Normal value: 800-8000μg/L (immunodiffusion or turbidity method) .   Nursing precautions   1. Do not eat greasy or high-protein foods the day before blood drawing , and avoid drinking a lot of alcohol. The ethanol content in the blood will directly affect the test results.   2. After 20:00 on the day before blood collection, you should fast for 12 hours to avoid affecting the test results.   3. When collecting urine specimens for examination, clean the vulva before collecting urine. The container used should be clean and free of contamination. Chemical substances such as detergents, disinfectants, and preservatives should not be mixed to avoid affecting the examination results.   4. Women should prevent leucorrhea from being mixed into urine. Pay attention to expelling part of the urine first, and then collect the specimen, that is, collect the mid-section urine.   5. Urine should be sent for testing immediately after retention to avoid erroneous test results caused by urine retention.   Related diseases   Malignant myxoma of the left atrium , mucocutaneous lymphaden syndrome, Takayasu arteritis, microscopic polyangiitis , nonspecific systemic necrotizing small vessel vasculitis , pediatric Historian-Johanne syndrome , pediatric Takayasu arteritis  , adult still’s disease, rheumatic fever, pediatric pneumonia   clinical significance   Clinical significance of CRP measurement:   (1) The levels of acute inflammation, tissue damage, myocardial infarction , surgical trauma, radiation damage and other diseases increase rapidly within hours after the onset, and tend to increase exponentially. When the disease improves, it quickly drops to normal, and its increase is positively correlated with the degree of infection. The patient’s CRP increases after surgery, and the CRP level should decrease 7 to 10 days after surgery. If CRP does not decrease or increases again, it indicates possible complications such as infection or thromboembolism.   (2) CRP is closely related to other inflammatory factors, such as the total number of white blood cells, erythrocyte sedimentation rate, and polymorphonuclear leukocytes. There is a positive correlation with WBC. Plays an active role in the inflammatory response and gives the body non-specific resistance. When a patient’s disease attacks, it can rise earlier than WBC and return to normal quickly, so it has extremely high sensitivity.   (3) Help identify types of respiratory infections. CRP can be used for the differential diagnosis of bacterial and viral infections: During bacterial infection, CRP levels increase; while during viral infections, CRP does not increase or is slightly increased. Therefore, the CRP value can help doctors identify the type of respiratory tract infection and be targeted. of medication and treatment.   (4) CRP is elevated in patients with malignant tumors . For example, the joint detection of CRP and AFP can be used for the differential diagnosis of liver cancer and benign liver diseases, and can be used to judge the efficacy and prognosis of liver cancer. CRP increases before surgery and decreases after surgery, and its response is not affected by radiotherapy, chemotherapy, and corticosteroid treatment, which is helpful to evaluate the progression of the tumor.   (5) Assess the severity of acute pancreatitis . When CRP is higher than 250 mg/L, it indicates extensive necrotizing pancreatitis.   (6) Using the ultra-sensitive latex enhanced method to measure CRP can improve the sensitivity of the measurement and can be used to predict the risk of coronary heart disease and myocardial infarction .

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eraser

What to do if the white bags, light-colored sofas or even the walls at home are dirty. It can’t be washed with water. It’s easy to crack. So what should I do? It seems very troublesome to find someone to clean it. Don’t worry, just use a small eraser to clean it. Bags, sofas and other leather products can be wiped with an eraser. It will not damage the surface, and the phone case can also be wiped with an eraser. There are many, many places that can be wiped with an eraser.   Introduction   name   English-Chinese translation: 1. [rubber] The general name for vulcanized rubber . 2. [eraser] Stationery made of rubber, which can erase traces of graphite or ink. There are many types of erasers, with different shapes and colors. There are ordinary fragrant erasers, 2B , 4B, 6B and other special art erasers for painting, as well as plastic erasers , etc.   principle   Pencil lead is made of graphite plus clay. Graphite is soft, black in color, and easily adheres to paper, so it can be written. The eraser is very soft, has high friction, and is somewhat sticky. When rubbed on the paper, the written words will stick away without damaging the paper surface. Therefore, the eraser can erase the pencil writing. If you write with a ballpoint pen , the ink will penetrate into the paper and be difficult to erase.   Relevant information   use correctly   When primary school students erase typos, they want to wipe them quickly and cleanly. They often dip an eraser into their saliva and then wipe. On the contrary, the typos are erased and the notebook is ruined. Especially for painting students, the backlit part of the sketch is often overdrawn, tired of the drawing, and dirty. At this time, if you continue to wipe it repeatedly, or even dip it in saliva , it will be ruined! The correct method should be: first dry wipe repeatedly on an empty piece of paper to get a lot of “rubber surface”, then gently pour the dough onto the area to be wiped off, and then gently rub the surface with the eraser. , it will be clean after a while, and the paper will not be damaged at all!

Ethylene glycol

This entry was edited and reviewed by the School of Chemical Sciences, University of Chinese Academy of Sciences , and certified by Popular Science China·Science Encyclopedia.   Ethylene glycol is also known as glycol and 1,2-ethylene glycol, referred to as EG. The chemical formula is (CH 2 OH) 2 and it is the simplest glycol . Ethylene glycol is a colorless, odorless, sweet liquid with low toxicity to animals. Ethylene glycol is miscible with water and acetone , but its solubility in ethers is small. Used as solvent, antifreeze and raw material for synthetic polyester. Polyethylene glycol (PEG), a polymer of ethylene glycol , is a phase transfer catalyst and is also used in cell fusion ; its nitrate ester is an explosive.   physical properties   Appearance: Colorless transparent viscous liquid   Melting point: -13 °C (lit.)   Molecular weight: 66.092   Boiling point: 195-198 °C   Glass transition temperature: -120 °C   Vapor pressure: 0.08 mmHg (20 ℃)   Density: 1.113 g/mL at 25 °C (lit.)   Refractive index: 1.4472 (λ: 589.3 nm; Temp: 20 °C)   Viscosity: 25.66 mPa.s (16℃)   Heat of combustion: 1180.26 kJ/mol   Autoignition point: 418 ℃   Critical temperature: 372 ℃   Critical pressure: 7699 kPa   Critical molar volume: 186 C3/mol   Eccentricity factor: 0.27   Surface tension: 46.49 mN/m (20℃)   CAS database: 107-21-1   NIST Chemical Substance Information: 1,2-Ethanediol(107-21-1)   EPA Chemical Substance Information: Ethylene glycol (107-21-1)   NIST Chemical Substance Information: 1,2-Ethanediol(107-21-1)   EPA Chemical Substance Information: Ethylene glycol (107-21-1)   Solubility: miscible with water/ethanol/acetone/glyceryl acetate pyridine, etc., slightly soluble in ether, insoluble in petroleum hydrocarbons and oils, able to dissolve calcium chloride/zinc chloride/sodium chloride/potassium carbonate/potassium chloride/ Inorganic substances such as  potassium iodide/potassium hydroxide.   At 25 degrees Celsius, the dielectric constant is 37.   t is easy to absorb moisture when the concentration is high.   Space between unit and number. Check the full text yourself later.、   chemical properties   Due to its low molecular weight and active nature , it can undergo esterification, etherification, alcoholization, oxidation, acetal, dehydration and other reactions.   Similar to ethanol, it can mainly react with inorganic or organic acids to form esters. Generally, only one hydroxyl group reacts first. By raising the temperature, increasing the amount of acid, etc., both hydroxyl groups can form esters. If it reacts with nitric acid mixed with sulfuric acid, dinitrate is formed. Acid chlorides or acid anhydrides easily form esters between two hydroxyl groups.   When ethylene glycol is heated under the action of a catalyst (manganese dioxide, aluminum oxide, zinc oxide or sulfuric acid), intramolecular or intermolecular water loss can occur.   Ethylene glycol can react with alkali metals or alkaline earth metals to form alkoxides. Usually, metals are dissolved in glycols to obtain only monoalkoxides; if this alkoxide (such as monosodium ethylene glycol) is heated to 180-200 °C in a hydrogen flow, disodium ethylene glycol and ethylene glycol can be formed.   In addition, ethylene glycol is heated with 2 mol of sodium methoxide to obtain disodium ethylene glycol. Disodium ethylene glycol reacts with alkyl halides to form ethylene glycol monoether or double ether. Disodium ethylene glycol reacts with 1,2-dibromoethane to form dioxane.   In addition, ethylene glycol is also easily oxidized. Depending on the oxidant used or the reaction conditions, various products can be generated, such as glycolaldehyde HOCH 2 CHO, glyoxal OHCCHO, glycolic acid HOCH 2 COOH, oxalic acid HOOCCOOH, carbon dioxide and water.   Ethylene glycol is different from other glycols in that the carbon chain can be broken when oxidized by periodic acid. Ethylene glycol can often be used instead of glycerin. In the tanning and pharmaceutical industries, it is used as a hydrating agent and solvent respectively.   Ethylene glycol derivatives dinitrates are explosives. Monomethyl ether or monoethyl ether of ethylene glycol is a good solvent, such as cellosolve HOCH2CH2OCH3, which can dissolve fiber, resin, paint and many other organic substances.   Ethylene glycol has strong solubility, but it is easily metabolized and oxidized to produce toxic oxalic acid, so it cannot be widely used as a solvent.   use   Mainly used to make polyester, polyester, polyester resin, hygroscopic agents, plasticizers, surfactants, synthetic fibers, cosmetics and explosives. It is also used as a solvent for dyes, inks, etc., to prepare antifreeze for engines, as a gas dehydrating agent, to manufacture resins, and as a wetting agent for cellophane, fiber, leather, and adhesives.   It can produce synthetic resin PET, fiber grade PET is polyester fiber, and bottle flake grade PET is used to make mineral water bottles, etc. It can also produce alkyd resin, glyoxal, etc., and is also used as antifreeze.   In addition to being used as antifreeze for automobiles, it is also used for the transportation of industrial cold energy. It is generally called a refrigerant. At the same time, it can also be used as a condensing agent like water. When using ethylene glycol as a refrigerant, you should pay attention to:   1. The freezing point changes with the concentration of ethylene glycol in the aqueous solution. When the concentration is below 60%, the freezing point decreases as the concentration of ethylene glycol in the aqueous solution increases. However, after the concentration exceeds 60%, as the concentration of ethylene glycol increases, the freezing point changes. As the concentration increases, its freezing point tends to rise, and the viscosity also increases as the concentration increases. When the concentration reaches 99.9%, its freezing point rises to -13.2°C. This is an important reason why concentrated antifreeze (antifreeze mother liquor) cannot be used directly and must attract the attention of users.   2. Ethylene glycol contains hydroxyl groups. When working at 80 degrees Celsius – 90 degrees Celsius for a long time, ethylene glycol will be oxidized first to glycolic acid and then to oxalic acid, that is, oxalic acid (oxalic acid), which contains 2 carboxyl groups. Oxalic acid and its by-products affect the central nervous system first, then the heart, and then the kidneys. Ethylene glycol and oxalic acid can corrode equipment and cause it to leak. Therefore, preservatives must also be included in the prepared antifreeze to prevent corrosion of steel and aluminum and the formation of scale.   Ethylene glycol methyl ether series products are high-grade organic solvents with excellent performance. They are used as solvents and diluents for printing inks, industrial cleaning agents, coatings (nitrocellulose paint, varnish, enamel), copper-clad laminates, printing and dyeing, etc. However, it is easily metabolized and oxidized to produce toxic oxalic acid, so it cannot be widely used as a solvent.   It can be used as an intermediate for the production of pesticides and pharmaceuticals, and is an intermediate for the fungicides pentoconazole and hymexazole. As well as raw materials for chemical products such as synthetic brake fluid; chemical fiber dyes for tanning, etc.   Adding ethylene glycol to hydraulic fluid can prevent oil-based hydraulic fluid from corroding the rubber in the system; water-based hydraulic fluid with ethylene glycol as the main component is an incombustible hydraulic fluid and is used in aircraft and automobiles. and molding machines that operate at high temperatures.   It is used as textile auxiliaries, synthetic liquid dyes, and raw materials for desulfurizers in fertilizer and oil refining production. Used as analytical reagents, chromatographic analysis reagents and capacitive media.   water antifreeze   Ethylene glycol is a colorless, slightly viscous liquid with a boiling point of 197.4°C and a freezing point of -11.5°C. It can be mixed with water in any proportion. After mixing, the freezing point is significantly reduced due to the change in vapor pressure of the cooling water.   The degree of decrease decreases with the increase of ethylene glycol content within a certain range. When the ethylene glycol content is 60%, the freezing point can be reduced to -48.3°C. When this limit is exceeded, the freezing point will rise instead.   Ethylene glycol antifreeze easily generates acidic substances during use , which has a corrosive effect on metals . Ethylene glycol is toxic, but due to its high boiling point, it does not produce vapor that can be inhaled into the body and cause poisoning.   Ethylene glycol has strong water absorption , and the storage container should be sealed to prevent it from overflowing after absorbing water.   Since the boiling point of water is lower than that of ethylene glycol, water is evaporated during use. When there is a lack ofcoolant , just add clean water.   This kind of antifreeze can be recycled after use (to prevent it from being mixed with petroleum products ). After sedimentation, filtration, adding water to adjust the concentration, and adding preservatives, it can continue to be used. Generally, it can be used for 3-5 years.   However, it must be filtered multiple times to prevent damage to the motor vehicle.   Many people think that the freezing point of ethylene glycol is very low. The freezing point of antifreeze is a neutral freezing point after mixing ethylene glycol and water in different proportions. In fact, this is not the case. The freezing point will be lower due to the change in the vapor pressure of the cooling water after mixing. significantly reduced.   The degree of decrease decreases with the increase of ethylene glycol content within a certain range, but once it exceeds a certain proportion, the freezing point will increase instead.   Antifreeze liquid mixed with 40% ethylene glycol and 60% soft water has an antifreeze temperature of -25°C; when the antifreeze liquid contains 50% ethylene glycol and 50% water, the antifreeze temperature is -35°C.   Freezing point measurement   Ethylene glycol is the main component of antifreeze, accounting for about 45% of the original antifreeze solution. The original antifreeze solution can be mixed with water in a certain proportion according to the temperature in various places to control the freezing point within an appropriate range. Effective antifreeze agents are various organic alcohols.   freezing point within an appropriate range. Effective antifreeze agents are various organic alcohols. Since the 1950s, almost all countries have used ethylene glycol as antifreeze. Ethylene glycol is a colorless, transparent, slightly sweet and hygroscopic viscous liquid that is misciblewith water in any proportion. When the concentration of ethylene glycol is different. The freezing point is also different. The freezing point of ethylene glycol-water antifreeze is not  linearly related to the mass fraction of ethylene glycol . The freezing point of its aqueous solution does not completely decrease with the increase of concentration. When the concentration exceeds 70%, the freezing point rises instead. During the preparation process , reasonable selection should be made based on reality to meet the requirements of antifreeze and economy . In Jiangnan , China , the ratio of ethylene glycol mass fraction is generally 40%, while in the cold north, the ratio of ethylene glycol mass fraction of about 50% is more suitable.   Packaging, storage and transportation   1. Store in a cool, ventilated warehouse. Keep away from fire and heat sources. They should be stored separately from oxidants and acids, and avoid mixed storage. Equipped with the appropriate variety and quantity of fire equipment. The storage area should be equipped with emergency release equipment and suitable containment materials. Due to its strong hygroscopicity, it should be stored sealed and sealed with nitrogen for long-term storage. Can be stored in iron, mild steel, copper or aluminum containers. However, coated steel, aluminum or stainless steel containers should be used for long-term storage.   2. The word “toxic” should be marked on the ethylene glycol container to prevent accidental ingestion and inhalation of ethylene glycol vapor. Operators should wear protective equipment and undergo regular physical examinations, especially routine urine examinations.   health hazards   Toxicity: Rat oral LD ​​50 =5.8mL/kg, mouse oral LD ​​50 =1.31~13.8mL/kg.   Routes of invasion : inhalation, ingestion, percutaneous absorption .   Health hazards : Inhalation poisoning manifests as recurrent syncope , nystagmus , and lymphocytosis. Acute poisoning after oral administration is divided into three stages: the first stage is mainly characterized by central nervous system symptoms , which in mild cases resemble ethanol poisoning , and in severe cases, rapid coma, convulsions, and death; in the second stage, cardiopulmonary symptoms are obvious, and severe cases may have pulmonary edema. , bronchopneumonia , heart failure ; the third stage mainly manifests as varying degrees of renal failure.   First aid measures Skin contact: Take off contaminated clothing and rinse with plenty of running water. Eye contact: Lift eyelids and rinse with running water or saline . Seek medical attention.   Inhalation: Move quickly to fresh air. Keep your airway open. If breathing is difficult , give oxygen. If breathing stops , perform artificial respiration immediately and seek medical attention.   Ingestion: Drink plenty of warm water and induce vomiting. Gastric lavage, diuresis. Seek medical attention. If breathing stops, perform artificial respiration immediately. Seek medical attention.   Toxicity to pets:   Ethylene glycol can be obtained from motorcycle antifreeze . The ethylene glycol in motorcycle antifreeze is not a threat to humans due to the addition of bittering agents and the small amount. However, if it is accidentally mixed with the food of pets (cats, dogs), Can cause poisoning in pets and cause kidney failure .   toxicological environment   Toxicity : It is of low toxicity.   Acute toxicity : LD 50 : 8.0~15.3g/kg (orally in mice); 5.9~13.4g/kg ( orally in rats );   Subacute and chronic toxicity : After eight days of inhalation of 12 mg/m 3 (several times in a row) in rats, 2/15 animals had corneal opacity and blindness; in humans, 9/28 inhaled a 40% ethylene glycol mixture and experienced temporary fainting ; in humans, inhalation Repeated inhalation of a 40% ethylene glycol mixture heated to 105°C caused nystagmus in 14/38 people and increased lymphocytes in 5/38 people .   Hazardous characteristics : There is a risk of combustion and explosion when exposed to open flame, high heat or contact with oxidants . If exposed to high heat, the internal pressure of the container will increase and there is a risk of cracking and explosion. Combustion (decomposition) products : carbon monoxide , carbon dioxide, water.

cellulose

Cellulose is a macropolysaccharide composed of glucose . Insoluble in water and general organic solvents. It is the main component of plant cell walls . Cellulose is the most widely distributed and abundant polysaccharide in nature, accounting for more than 50% of the carbon content in the plant kingdom. The cellulose content of cotton is close to 100%, making it the purest natural source of cellulose. In general, cellulose accounts for 40-50% of wood, with 10-30% hemicellulose and 20-30% lignin .   Cellulose is the main structural component of plant cell walls and is usually combined with hemicellulose, pectin and lignin. The way and extent of its combination has a great impact on the texture of plant-derived foods. The changes in texture of plants during maturity and post-ripening are caused by changes in pectin substances. Cellulase does not exist in the human digestive tract, and cellulose is an important dietary fiber. It is the most widely distributed and abundant polysaccharide in nature.   nature   solubility   At room temperature, cellulose is neither soluble in water nor general organic solvents, such as alcohol , ether , acetone , benzene , etc. It is also insoluble in dilute alkali solutions and can be dissolved in cuprammonium Cu(NH 3 ) 4 (OH ) 2 solution and copper ethylenediamine [NH 2 CH 2 CH 2 NH 2 ]Cu(OH) 2 solution, etc. Therefore, it is relatively stable at room temperature because of the hydrogen bonds between cellulose molecules .   Cellulose hydrolysis   Under certain conditions, cellulose reacts with water. During the reaction, the oxygen bridge is broken, and water molecules are added at the same time, and the cellulose changes from long chain molecules to short chain molecules until all the oxygen bridges are broken and becomes glucose.   Cellulose oxidation   Cellulose reacts chemically with oxidants to produce a series of substances with different structures from the original cellulose. This reaction process is called cellulose oxidation. The base ring of the cellulose macromolecule is a macromolecular polysaccharide composed of D-glucose with β-1,4 glycosidic bonds . Its chemical composition contains 44.44% carbon, 6.17% hydrogen, and 49.39% oxygen. Due to different sources, the number of glucose residues in cellulose molecules, that is, the degree of polymerization (DP), is in a wide range. It is the main component of the cell walls of vascular plants , lichen plants , and some algae. Cellulose is also found in the capsules of Acetobaeter and the tunicates of urochordates. Cotton is a highly pure (98%) cellulose. The name α-cellulose refers to the part of the original cell wall of the complete cellulose standard sample that cannot be extracted with 17.5% NaOH. β-cellulose (β-cellulose) and γ-cellulose (γ-cellulose) are cellulose corresponding to hemicellulose .   Although α-cellulose is usually mostly crystalline cellulose, β-cellulose and γ-cellulose chemically contain various polysaccharides in addition to cellulose. The cellulose of the cell wall forms microfibrils. The width is 10-30 nanometers, and the length can reach several micrometers. Apply X-ray diffraction and negative staining methods(Negative staining method), according to electron microscope observation, the crystalline parts of chain-like molecules arranged in parallel form basic microfibers with a width of 3-4 nanometers. It is speculated that these basic microfibers are aggregated to form microfibers. Cellulose can be dissolved in Schwitzer’s reagent or concentrated sulfuric acid. Although it is not easily hydrolyzed by acid, dilute acid or cellulase can produce D-glucose, cellobiose and oligosaccharides from cellulose . Acetic acid bacteria have an enzyme that transfers glycosides from UDP glucose primer to synthesize cellulose.   Standard samples of granular enzymes with the same activity have been obtained in higher plants. This enzyme usually utilizes GDP glucose, and in the case of transfer from UDP glucose, mixing of β-1,3 bonds occurs. Where microfibrils form and the mechanisms that control cellulose alignment are less clear. On the other hand, regarding the decomposition of cellulose, it is estimated that when the primary cell wall stretches and grows, part of the microfibers is decomposed by the action of cellulase and becomes soluble.   Water can cause limited swelling of cellulose, and certain aqueous solutions of acids, alkalis, and salts can penetrate into the crystalline area of ​​the fiber, causing unlimited swelling and dissolving the cellulose. Cellulose does not undergo significant changes when heated to about 150°C. Above this temperature it will gradually coke due to dehydration. Cellulose reacts with concentrated inorganic acids to hydrolyze to produce glucose, reacts with concentrated caustic alkali solutions to produce alkali cellulose, and reacts with strong oxidants to produce oxidized cellulose.   Flexibility   Cellulose has poor flexibility and is rigid because:   (1) Cellulose molecules are polar and the interactions between molecular chains are strong;   (2) The six-membered pyran ring structure in cellulose makes internal rotation difficult;   (3) Hydrogen bonds can be formed both within and between cellulose molecules. In particular, intramolecular hydrogen bonds prevent the glycosidic bonds from rotating, thereby greatly increasing their rigidity.   Preparation method   Production method 1: Cellulose is the most abundant natural polymer compound in the world. The production raw materials come from wood, cotton, cotton linters, wheat straw, rice straw, reed, hemp, mulberry bark, mulberry bark and sugarcane bagasse. Due to insufficient forest resources in our country, 70% of cellulose raw materials come from non-timber resources. The average cellulose content of my country’s softwood and broadleaf wood is about 43-45%; the average cellulose content of grass stems is about 40%. The industrial production method of cellulose is to cook plant raw materials with sulfite solution or alkali solution, mainly to remove lignin, which are called sulfite method and alkali method respectively. The resulting materials are called sulfite pulp and alkali pulp. The residual lignin is then further removed through bleaching, and the resulting bleached pulp can be used for papermaking. After further removing hemicellulose, it can be used as a raw material for cellulose derivatives.   Production method two: Pound fibrous plant raw materials and inorganic acid into a slurry to make α-cellulose, and then process it to partially depolymerize the cellulose, and then remove the non-crystalline part and purify it.   Production method three: decompose the selected industrial wood pulp board, and then send it to a reaction kettle with 1% to 10% hydrochloric acid (the dosage is 5% to 10%) for hydrolysis at a temperature of 90 to 100°C. The reaction time is 0.5 to 2 hours. After the reaction is completed, it is cooled and sent to a neutralization tank. It is adjusted to neutrality with liquid caustic soda. After filtration, the filter cake is dried at 80 to 100°C and finally crushed to obtain the product.   Production method four: cellulose made from wood pulp or cotton pulp. It is refined after bleaching treatment and mechanical dispersion.   effect   Cellulose is the oldest and most abundant natural polymer on earth. It is inexhaustible and the most precious natural renewable resource for mankind. Cellulose chemistry and industry began more than 160 years ago and was the main research object during the birth and development period of polymer chemistry. The research results of cellulose and its derivatives contributed to the creation, development and enrichment of the disciplines of polymer physics and chemistry. Made significant contributions.   Physiological effects   There is no β-glycosidase in the human body and cellulose cannot be decomposed and utilized. However, cellulose can absorb a large amount of water, increase the amount of feces, promote intestinal peristalsis, accelerate the excretion of feces, and shorten the residence time of carcinogens in the intestines. Reduces adverse irritation to the intestines, thereby preventing intestinal cancer.   Dietary fiber   The fiber in human diet is mainly contained in vegetables and roughly processed cereals. Although it cannot be digested and absorbed, it can promote intestinal peristalsis and facilitate fecal discharge. Herbivores rely on symbiotic microorganisms in their digestive tracts to break down cellulose so it can be absorbed and utilized. Food fiber includes crude fiber, semi-crude fiber and lignin. Food fiber is a substance that cannot be digested and absorbed. In the past, it was considered as “waste”. In 2013, it was considered that it plays an important role in protecting human health and prolonging life. Therefore, it is called the seventh nutrient.   Dietary fiber generally uses various types of high-purity dietary fiber extracted from natural foods (konjac, oats, buckwheat, apples, cactus, carrots, etc.). The main functions of dietary fiber are:   (1) Treatment of diabetes Dietary fiber can improve the sensitivity of insulin receptors and improve the utilization rate of insulin ; dietary fiber can wrap the sugar in food so that it is gradually absorbed, balancing postprandial blood sugar, thus regulating the blood sugar level of diabetic patients and treating diabetes. role.   (2) Prevention and treatment of coronary heart disease Elevated serum cholesterol levels can lead to coronary heart disease. The excretion of cholesterol and bile acid is closely related to dietary fiber. Dietary fiber can combine with cholic acid, causing cholic acid to be quickly excreted from the body. At the same time, the combination of dietary fiber and cholic acid will promote the conversion of cholesterol into cholic acid, thereby reducing cholesterol levels.   (3) Antihypertensive effect Dietary fiber can absorb ions and exchange with sodium ions and potassium ions in the intestines, thereby reducing the sodium-potassium ratio in the blood and thus lowering blood pressure.   (4) Anti-cancer effect Since the 1970s, there have been an increasing number of research reports on the role of dietary fiber in anti-cancer, especially the relationship between dietary fiber and digestive tract cancer. Early surveys in India showed that people living in northern India consumed much more dietary fiber than those in the south, and the incidence of colon cancer was also much lower than in the south. Based on this survey result, scientists conducted more in-depth research and found that dietary fiber prevents and treats colon cancer for the following reasons: some saprophytic bacteria in the colon can produce carcinogens, and some beneficial microorganisms in the intestine can use dietary fiber to produce short-chain fatty acids . This type of short-chain fatty acid can inhibit the growth of saprophytic bacteria; cholic acid and ichonecholic acid in bile can be metabolized by bacteria into carcinogens and mutagens of cells. Dietary fiber can bind cholic acid and other substances and excrete them out of the body, preventing The production of these carcinogens; dietary fiber can promote intestinal peristalsis, increase stool volume, shorten emptying time, thereby reducing the chance of contact between carcinogens in food and the colon; beneficial bacteria in the intestines can use dietary fiber to produce butyric acid, butyric acid It can inhibit the growth and proliferation of tumor cells, induce the transformation of tumor cells into normal cells, and control the expression of oncogenes.   (5) Weight loss and treatment of obesity Dietary fiber replaces part of the nutrients in food, reducing the total food intake. Dietary fiber promotes the secretion of saliva and digestive juices, filling the stomach. At the same time, it absorbs water and expands, which can produce a feeling of satiety and inhibit the desire to eat. Dietary fiber combines with some fatty acids. This combination prevents the fatty acids from being absorbed when they pass through the digestive tract, thus reducing the absorption rate of fat.   (6) Treat constipation Dietary fiber has strong water-holding properties, and its water absorption rate is as high as 10 times. After it absorbs water, it increases the volume of intestinal contents, making stool loose and soft, making it smoother and less laborious when passing through the intestines. At the same time, dietary fiber, as a foreign body in the intestine, can stimulate the contraction and peristalsis of the intestine, speed up stool excretion, and cure constipation.   Research results   An international team, including researchers from the University of Göttingen in Germany, were surprised to find that despite the simulated Martian atmosphere disrupting the microbial ecology of the kombucha cultures, they were studying the possibility of kombucha surviving in a Martian-like environment. A cellulose-producing bacterium of the genus Colomata survived. The findings were recently published in the journal Frontiers in Microbiology. The findings suggest that cellulose produced by bacteria may be responsible for their survival in alien conditions. It also provides the first evidence that bacterial cellulose may be a biomarker of alien life, and that cellulose-based membranes may be good materials for protecting life in alien colonies.   In 2014, researchers with the Biology and Mars Experiment (BIOMEX) project, supported by the European Space Agency (ESA), sent kombucha cultures to the International Space Station (ISS) to better understand cellulose as a biomarker the robustness of animals, the genome structure of kombucha, and its alien survival behavior. The samples were reactivated on Earth and cultured a year and a half later for another two and a half years outside the ISS under simulated Martian conditions.   ingest   Vegetables are rich in fiber. Foods that do not contain fiber include: chicken, duck, fish, meat, eggs, etc.; foods that contain a lot of fiber include: whole grains, bran, vegetables, beans, etc., among which cotton has the highest content, reaching 98%. Therefore, it is recommended that diabetic patients eat more fiber-rich foods such as beans and fresh vegetables. At present, domestic plant fiber foods are mostly made from rice bran, bran, wheat grains, beet shavings, pumpkins, corn husks and seaweed plants, etc., which have a certain effect on lowering blood sugar and blood lipids.   Content and determination   Although fiber cannot be absorbed by the human body, it has a good effect on cleaning the intestines and is a healthy food suitable for patients with IBS (irritable bowel syndrome). The fiber content of common foods is as follows:   Wheat bran: 31% Grains: 4-10%, arranged from most to least: wheat grains, barley, corn, buckwheat noodles, barley noodles, sorghum rice, and black rice. Cereal: 8-9%; Oatmeal: 5-6% The cellulose content of potatoes, sweet potatoes and other tubers is about 3%. Beans: 6-15%, from most to least, they are soybeans, green beans, broad beans, kidney beans, peas, black beans, red beans, and mung beans.   Whether cereals, potatoes or beans, generally speaking, the more finely processed they are, the less fiber they contain.   Vegetables: Bamboo shoots have the highest content. The fiber content of dried bamboo shoots reaches 30-40%, and the fiber content of peppers exceeds 40%. Others containing more fiber include: bracken, cauliflower, spinach, pumpkin, cabbage, and rapeseed.   Fungi (dry): The cellulose content is the highest. Among them, the cellulose content of pine mushrooms is close to 50%. The cellulose content of more than 30% is arranged from most to least: shiitake mushrooms, tremella, and fungus. In addition, the fiber content of seaweed is also high, reaching 20%.   Nuts: 3-14%. More than 10% include: black sesame seeds, pine nuts, and almonds; less than 10% include white sesame seeds, walnuts, hazelnuts, walnuts, sunflower seeds, watermelon seeds, and peanut kernels.   Fruits: Dried red fruits contain the most fiber, with a fiber content of nearly 50%, followed by dried mulberries, cherries, wild jujubes, black dates, jujubes, small jujubes, pomegranates, apples, and pears.   All kinds of meat, eggs, dairy products, various oils, seafood, alcoholic beverages, and soft drinks do not contain cellulose; the fiber content of various infant foods is extremely low.   Cellulose is not fiber, they are two different concepts. Cellulose is measured using a cellulose analyzer. Crude fiber is generally measured, and dietary fiber is also measured in foods   Medicinal introduction   Natural dietary fiber tablets   (1) Edible purpose : Moisturizes the intestines and relieves constipation, provides a feeling of satiety and breaks down fat.   (2) Product features : Scientific formula derived from natural ingredients helps normal physiological activities and helps you feel full. Fiber can remove disease-causing toxins from the body through the digestive system. Shorten the time food stays in the intestines and make bowel movements smooth.Made of a unique combination of fibers that break down ingested fat.   (3) Main ingredients : Calcium hydrogen phosphate, cellulose, apple fiber, acacia flower, lecithin, calcium carbonate, citrus fiber, silicon dioxide, oat fiber, magnesium stearate, dextrin, maltodextrin, sodium carboxymethylcellulose, citric acid sodium.   (4) Recommended usage : Take one to two tablets each time for laxative, three times a day, 20 minutes before meals or with boiled water after meals.   Fiber and health   Not all carbohydrates can be digested and converted into glucose. Carbohydrates that are difficult to digest are called fiber. It is an integral part of a healthy diet and is found in higher amounts in fruits, vegetables, lentils, beans and whole grains. Eating foods high in fiber can reduce the likelihood of bowel cancer, diabetes and diverticular disease. It is also less prone to constipation.   People often think of fiber as “forage,” but that’s not the case. Fiber absorbs water. Therefore, it makes food particles expand and loosen, making them easier to pass through the digestive tract. Since the time that food residues stay in the body is shortened, the risk of infection is reduced; moreover, when some foods, especially meat, spoil, they will produce carcinogens and cause cell mutations. The shortening of the time that food residues stay in the body can also reduce the risk of infection. Reduce the likelihood of this happening. Regular meat eaters’ diets are low in fiber, which increases the time food remains in the intestines to 24-72 hours, during which time some food may spoil. So if you like to eat meat, then you have to make sure that you also include plenty of fiber in your diet.   There are many types of fiber, some of which are proteins rather than carbohydrates. Some types of fiber, like the kind found in oats, are called “soluble fiber” and bind to sugar molecules to slow the absorption of carbohydrates. This way they help keep blood sugar levels stable. Some fibers are much more absorbent than others. Wheat fiber can swell to 10 times its original volume in water, while glucomannan fiber in Japanese konjac can swell to 100 times its original volume in water. Because fiber bulks food and slows the release of energy from sugars, highly absorbent fiber can help control appetite and help maintain proper weight.   The ideal fiber intake is no less than 35 grams per day. With proper food selection, this standard can easily be achieved without the need for additional supplementation. It’s still best to get your fiber from a number of different food sources, including oats, lentils, broad beans, seeds, fruits, and raw or lightly cooked vegetables. Most of the fiber in vegetables is destroyed during cooking, so vegetables are best eaten raw.

Glucose(organic compounds)

Glucose, organic compound , molecular formula C 6 H 12 O 6. It is the most widely distributed and important monosaccharide in nature . It is a polyhydroxyaldehyde. Pure glucose is a colorless crystal, sweet but not as sweet as sucrose . It is easily soluble in water, slightly soluble in ethanol , and insoluble in ether . The optical rotation of natural glucose aqueous solution is to the right, so it belongs to ” dextrose “.         Glucose plays an important role in the field of biology . It is the energy source and metabolic intermediate product of living cells , that is, the main energy supply substance of organisms. Plants produce glucose through photosynthesis . It is widely used in candy manufacturing and pharmaceutical fields.   A brief history of research   In 1747, the German chemist S. Marggraf was in Berlin Glucose was isolated for the first time and the process was published in “Chemical Experiments on the Extraction of Sucrose from Several Plants Originating in Germany” in 1749In the article, page 90 reads: “Moisten raisins with a small amount of water to soften them, and then squeeze the squeezed juice. After purification and concentration, a sugar is obtained. The sugar discovered by Magraf is glucose.   However, glucose was not named until 1838. Its English name glucose is derived from the French glucose . It was first created by French professor Eugène-Melchior Péligot (1811-1890). From the German word gleukos – unfermented sweet fruit wine , the prefix gluc- comes from the German glykys , which means sweet, and the suffix -ose indicates its chemical classification, indicating that it is a carbohydrate .     In the same year, Louis Jacques Thénard , Joseph Louis Gay-Lussac , Jean – BaptisteBiot and Jean -Jean Baptiste AndreDumas Four French scientists jointly published a review of Mr. Perigo’s collection of academic papers, titled “Research on Nature and the Chemistry of Sugars” Study,” on page 109, reads: “Those derived from grapes, starch, honey, and even substances that cause diabetes have the same composition and properties, naming this single substance glucose.     Due to the important position of glucose in living organisms, understanding its chemical composition and structure became an important topic in organic chemistry in the 19th century. In 1884, Emil Fischer began to study sugars . There were only four types of monosaccharides known at that time : two aldohexoses (glucose, galactose ) and twoketohexoses ( fructose , sorbose ). They have the same molecular formula C 6 H 12 O 6 , Chemistry at the University of Munich H.iKhani preliminarily found that glucose and galactose are linear five-hydroxy aldehydes, and fructose and sorbose are linear five-hydroxy ketones .     Fisher discovered that glucose, fructose, and mannose formed the same vein as benzene, and therefore concluded that these three sugars had the same configuration below the second carbon atom. According to the stereoisomerismtheory of Van’tHoff andeLeBl, Fisher deduced that aldohexose has 16 possible configurations, using methods such as oxidation, reduction, degradation, and addition . , by 1891, he determined the configuration of all members of D-aldohexose. [4]In 1892, the German chemist Fischer determined the chain structure of glucose and its stereoisomers, and won the 1902Nobel Prize in Chemistry for his great achievements in stereochemistry .      In April 2022, Chinese scientists used electrocatalysis combined with biosynthesis to efficiently reduce carbon dioxide to synthesize high-concentration acetic acid, and further use microorganisms to synthesize glucose and oil. This achievement was jointly completed by the University of Electronic Science and Technology of China, the Shenzhen Institute of Advanced Technology of the Chinese Academy of Sciences and the University of Science and Technology of China. It was published as a cover article in the international academic journal “Nature Catalysis” on April 28, 2022.      On August 15, 2023, the famous academic journal ” Science Bulletin ” published the latest research results showing that Chinese scientists achieved precise total synthesis from carbon dioxide to sugar in the laboratory, taking a key step in artificially synthesizing sugar. The research results were completed by the scientific research team of Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences and Dalian Institute of Chemical Physics, which took more than two years to complete. The team mixed high-concentration carbon dioxide and other raw materials in a certain proportion in the reaction solution, and under the action of chemical catalysts and enzyme catalysts, four kinds of hexoses were obtained:     glucose, psicose, tagatose, and mannose. Hexose is the collective name for sugars that are widely distributed in nature and are most closely related to the body’s nutritional metabolism.     Physical and chemical properties   Glucose is colorless crystal or white crystalline or granular powder; odorless, sweet, hygroscopic, and easily soluble in water.     ⒈Optical activity The specific optical rotation value of α-D-glucose at 20°C is +52.2°.     ⒉Solubility _ The maximum concentration of a single glucose solution is 50% at 20°C.     ⒊Sweetness _ The specific sweetness of α-D-glucose is 0.7.     ⒋Viscosity _ The viscosity of glucose increases with increasing temperature.     Density : 1.581g/cm 3     Melting point: 146ºC     Boiling point : 527.1ºC at 760 mmHg     Flash point : 286.7ºC     Refractive index :1.362     Storage conditions: 2-8ºC     chemical properties   It is the most widely distributed monosaccharide in nature. Glucose contains five hydroxyl groups and one aldehyde group , and has the properties of polyol and aldehyde .     It easily decomposes when heated under alkaline conditions. Should be kept airtight. It is rapidly absorbed after oral administration and is utilized by tissues after entering the human body. 1 mol of glucose releases 2870 kJ of energy after complete oxidation reaction in the human body. Part of this energy is converted into 30 or 32 mol of ATP. The rest of the energy is dissipated in the form of heat energy to maintain the body temperature. It can also be converted into glycogen or fat for storage through the liver or muscles. .   (1) The aldehyde group in the molecule has reducing properties and can react with silver ammonia solution and be oxidized into ammonium gluconate .   (2) The aldehyde group can also be reduced to hexanehexanol.     (3) There are multiple hydroxyl groups in the molecule, which can undergo esterification reactions with acids.     (4) Glucose undergoes oxidation reaction in the body and releases heat.   (5) Glucose can be produced by hydrolysis of starch under the catalysis of enzyme or sulfuric acid.     (6) Plant photosynthesis .   (7) Glucose reacts with newly prepared copper hydroxide .   (8) Glucose decomposes into water and carbon dioxide under certain conditions .     (9) Hydrolysis of maltose.   (10) Hydrolysis of starch and cellulose.    Preparation     1. The sugar aqueous solution obtained by partially hydrolyzing edible corn starch with food-grade acids and/or enzymes is purified and concentrated. Due to different degrees of hydrolysis, the amount of D-glucose contained can vary greatly. Those made from corn starch are called “corn syrup”.       2. Glucose can be obtained by hydrolyzing starch with hydrochloric acid or dilute sulfuric acid. It can also be made from starch as raw material under the action of starch glucoamylase.       Physiology and biochemistry   The central nervous systemrelies almost entirely on the supply of blood sugar as energy. Once blood sugar rises to 80 mg%, diabetes may occur.     Industrially, glucose is produced by hydrolysis of starch. In the 1960s, microbial enzymatic methods were used to produce glucose. This is a major innovation and has obvious advantages over acid hydrolysis. In production, the raw materials do not need to be refined, and there is no need for acid-resistant or pressure-resistant equipment. Moreover, the sugar liquid has no bitter taste and has a high sugar production rate.     Glucose is mainly used as an injectable nutritional agent ( glucose injection ) in medicine.     In the food industry, fructose can be produced from glucose after isomerase treatment, especially fructose syrup containing 42% fructose , which has the same sweetness as sucrose and has become an important product in the current sugar industry.     Glucose is an indispensable nutrient for metabolism in living organisms. The heat released by its oxidation reaction is an important source of energy required for human life activities. It can be used directly in the food and pharmaceutical industries. It is used as a reducing agent in the printing, dyeing and tanning industry. Glucose is commonly used asa reducing agent in the mirror-making industry and the silver plating process of thermos bottles . In industry, a large amount of glucose is used as raw material to synthesize vitamin C (ascorbic acid).   metabolic function   Glucose is easily absorbed into the bloodstream, so it is often used by hospital personnel, sports enthusiasts, and everyday people as a powerful, quick energy boost.     Glucose enhances memory, stimulates calcium absorption and increases intercellular communication. But too much can raise insulin concentrations, leading to obesity and diabetes; too little can cause hypoglycemia or worse, insulin shock ( diabetic coma ). Glucose is important for brain function, and glucose metabolism can be disrupted by: depression, bipolar disorder, anorexia, and bulimia. Alzheimer’s disease patients record lower glucose concentrations than other brain abnormalities, leading to strokes or other vascular diseases. Researchers found that supplementing the diet with 75 grams of glucose increased memory test scores.      Glucose is absorbed into liver cells, reducing glycogen secretion, causing muscle and fat cells to increase glucose uptake. Excess blood glucose is converted into fatty acids and triglycerides in the liver and fatty tissue.   Indications    Glucose is widely used clinically to provide water and calories for patients with high fever, dehydration, coma or inability to eat. When a large amount of body fluid is lost in the body, such as vomiting, diarrhea, massive blood loss, etc., 5% to 10% glucose and physiological saline can be infused intravenously to supplement water, salt and sugar, and can be used for patients with hypoglycemia and drug poisoning. Intravenous infusion of 25% to 50% hypertonic solution can cause tissue dehydration and temporary diuresis due to its high osmotic effect. It can be used alternately with mannitol to treat cerebral edema, pulmonary edema and reduce intraocular pressure. Hypoglycemia is treated with intravenous infusion of hypertonic glucose. Combined with insulin, it can promote the transfer of potassium into cells and is also one of the treatment measures for hyperkalemia .   Decomposition pathway    Natural glucose, whether free or combined, belongs to the D configuration. In aqueous solution, it mainly exists in the pyran configuration of oxygen-containing rings, and is an equilibrium mixture of α and β configurations. Under normal temperature conditions, crystals can be precipitated from a supersaturated aqueous solution in the form of α-D-glucose hydrate (containing 1 water molecule), with a melting point of 80°C; while crystals precipitated between 50 and 115°C are free. Water α-D-glucose, melting point 146°C. The stable form precipitated above 115℃ is β-D-glucose , with a melting point of 148~150℃. The furan ring form of glucose only exists in a bound state in a few natural compounds.     D-glucose has the chemical properties of general aldose : under the action of oxidants, it generates gluconic acid, glucaric acid or glucuronic acid ; under the action of reducing agents, it generates sorbitol; under the action of weak bases, glucose can react with the other two Six-carbon sugars with similar structures – fructose and mannose – are converted into each other through the enol form. Glucose can also combine with phenylhydrazine to form glucoside, which is different from other glucosides in terms of crystal shape and melting point and can be used as a means to identify glucose.     Most organisms have enzyme systems that break down D-glucose for energy. In living cells, such as mammalian muscle cells or single-cell yeast cells, glucose successively passes through the aerobic glycolysis pathway, the aerobic tricarboxylic acid cycle, and the biological oxidation process to generate carbon dioxide and water, releasing relatively large amounts of carbon dioxide and water. A large amount of energy is stored in the form of ATP ( adenosine triphosphate ) for growth, movement and other life activities. In the absence of oxygen, glucose is only decomposed into lactic acid or ethanol, releasing much less energy. Brewing is an anaerobic decomposition process. Industrially, glucose obtained by hydrolyzing starch with acid or enzyme can be used as raw material for food, wine, pharmaceutical and other industrial production.     Application areas   (1) Fermentation industry   The growth of microorganisms requires a suitable carbon-to-nitrogen ratio. Glucose, as the carbon source of microorganisms, is the main ingredient of fermentation culture media . Antibiotics, monosodium glutamate, vitamins, amino acids, organic acids, enzyme preparations, etc. all require large amounts of glucose. Glucose can also be used. As a raw material for microbial polysaccharides and organic solvents.   (2) Food industry     At present, crystallized glucose is mainly used in the food industry. With the improvement of living standards and the continuous development of science and technology in the food industry, glucose is increasingly used in the food industry. The food industry will still be the largest market for a long time to come.      (3) Chemical industry      Glucose is also widely used in industry. It is used as a reducing agent in the printing, dyeing and tanning industry. Glucose is also commonly used as a reducing agent in the mirror-making industry, thermos bottle silver plating, glass fiber silver plating and other chemical silver plating industries.     Application of glucose in the manufacture of chrome tanning agents in the tanning industry: Chromium tanning agents are the best tanning agents for manufacturing light leather (shoe upper leather, clothing leather) . Chromium salts have been used to make leather for 100 years. The leather produced has the characteristics of high shrinkage temperature, good elasticity, resistance to flexing, washing resistance, solidity and durability. The chromium tanning agent is mainly basic chromium sulfate (basic chromium chloride can also be used, but its tanning agent effect is worse than chromium sulfate). The manufacturing method is to use glucose or sulfur dioxide as a reducing agent to reduce dichromate into basic chromium sulfate in a sulfuric acid solution to make a chromium tanning liquid. After the tanning liquid is concentrated and dried, a powdery chromium tanning agent can be obtained. .     (4) Synthesis and transformation     Glucose can be synthesized or converted into other products through hydrogenation, oxidation, isomerization, alkaline degradation, esterification, acetalization, etc. Such as hydrogenation to produce sorbitol; oxidation to produce glucuronic acid, diacid, etc., and can be further produced into calcium acid, sodium acid, zinc acid and gluconodelta lactone; isomerization into F42, F55, F90 fructose syrup and crystallization Fructose; it can also be isomerized into mannose (raw material for the production of mannitol), of which sorbitol can further generate vitamin C , which is widely used in clinical treatment, and 15% mannitol is clinically used as a safe and effective way to reduce intracranial pressure medications to treat cerebral edema and glaucoma.   

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Offset printing press(Lithographic printing press)

An offset printing press is a type of lithographic printing press . During printing, the printed images and text are first printed from the printing plate onto the rubber cylinder, and then transferred to the paper by the rubber cylinder.     Offset printing machines can be divided into sheet-fed offset printing machines and web-fed offset printing machines according to different paper feeding methods; according to the number of printing colors completed in one paper pass, they can be divided into single-color, two-color, four-color and multi-color printing machines; according to the printing substrate The maximum paper format can be divided into small offset printing presses , six-open, four-open, half-open and full-sheet printing presses.   In addition, there are double-sided printing presses that can complete two-sided printing at the same time in one paper pass. Sheet-fed offset printing press is a lithographic printing press , used for printing high-grade commercial prints and packaging prints, and is the mainstream of modern paper printing.   development path   birth   In 1904, Mr. Caspar Hermann of Germany was trying to improve lithographic printing technology, trying to find a new production method through countless experiments. The American Mr. Ella Washington Roubaix got involved in this research work by accident. During a printing job, Ira Washington Roubaix noticed that a piece of paper did not travel along the normal path during the printing process. He tried to print patterns on both the front and back of the paper. The image was first transferred from the printing plate to On the blanket of the impression cylinder , and then onto the paper. An unexpected scenario occurred: This indirect imprinting method produced a product with higher printing quality, and the elastic blanket surface transferred the ink to the paper more evenly. The printing method developed simultaneously by Caspar Hermann and Ira Washington Roubaix was born. This is the origin of what we often call offset printing. They separately designed sheet-fed offset printing equipment, but it was not immediately commercialized. It was not until 1912 that the world’s first web offset printing equipment, Universal, was launched, with a speed of 8,000 sheets/hour, and the offset printing machine was truly recognized by the world.   prototype   In 1911, KBA and Manroland , which had decades of experience in the production of letterpress and gravure printing machines , developed their first offset printing machines. From then on, they began to make more attempts in the field of printing.   In the 1920s, companies such as Manroland, KBA, and Komori all launched their own sheet-fed and web-fed offset printing equipment. In cooperation with related companies, we have developed various automated printing equipment with paper delivery units, refrigeration units, folding and drum drying components.   In 1932, KBA (Radebeul Company) launched the world’s first four-color sheet-fed offset printing press, Planeta-Deca, which took offset printing technology a big step forward.   World War II destroyed many factories, and the development of offset printing technology was also affected, stagnating for more than ten years. In the 1940s, the boom in American newspaper production and mass circulation further promoted the advancement of offset printing technology. After 1945, offset printing made it possible to achieve high quality and high requirements for commercial advertising. In contrast, producing four-color continuous-tone images using letterpress printing techniques became expensive and time-consuming. As the industry’s demand for image and printing quality continues to increase, offset printing technology has made new breakthroughs.   growing up   In the 1950s, printing technology emerged one after another and developed rapidly. The emergence of imagesetters broke the 540-year printing history of movable type typesetting for the first time and led to the emergence of digital image and text typesetting. Especially the emergence of the second generation imagesetters in 1954 made the typesetting technology Go to the next level. In 1956, the emergence of prefabricated photosensitive plates (PS plates) and plate-making equipment made offset printing technology a fish in water. At the same time, the demand for offset printing technology increased significantly. In the 1950s, manroland, KBA, Komori, Akiyama, etc. successively developed their own two-color and four-color offset printing equipment.   In the 1960s, the issue of ink balance during the printing process became the key to the development of offset printing technology. He invented alcohol dampening solution, and since the advent of the Dahlgren continuous dampening system in 1960, offset printing has begun to reach the level of clarity achieved by letterpress printing and compete with mature letterpress printing for the market.   In 1962, Heidelberg launched KOR, an offset printing machine modified from a letterpress printing machine, on drupa, thus entering the offset printing market. The emergence of small offset printing equipment such as KOR, as well as the ABDick350 and 360 series of small offset printing machines, attracted a large number of offset printing machine users. Most of them are small printing companies, which drives the rapid development of offset printing on a global scale. At this stage, various offset press manufacturers continued to launch new offset presses. In 1965, KBA made a huge breakthrough in sheet-fed offset printing technology and produced the world’s first unit-type and double-diameter imprinting and paper transfer machines. Cylinder printing press, this design was adopted and is still the mainstream form of sheet-fed printing press today.   Although the offset printing process had not yet been widely adopted around the world at this time, a considerable number of people had realized that it was a better quality and more accurate printing method.   In the 1970s, commercial printing began to develop vigorously. Printing technology (color printing system) developed towards automatic high-end color separation technology and full-page typesetting design system. It gradually bid farewell to photographic color separation and manual color separation, making color images easier to transmit and Realize “what you see is what you get”. Although the color printing system is expensive and cannot be widely used in printing plants, it has been concluded that it is the future development direction of offset printing technology.   The electrostatic printing introduced by Xerox at that time also pushed offset printing technology to a new level in a sense. The convenience and speed of electrostatic printing are particularly suitable for the needs of short-run printing, forcing printer manufacturers to keep up with market demand and focus on To improve the printing speed and automation of the equipment. Therefore, in the offset printing presses launched during this period, the unit printing press, button control and mechanical automatic ink supply system became standard configurations, and the printing speed was also improved.   At this time, various offset printing rookies continued to appear. In 1971, Akiyama originally designed and developed a 3-diameter impression cylinder and a four-open, four-color machine Hi-Ace426 with a speed of 10,000 sheets per hour; in 1972, Manroland produced the first modular machine Printing press – Rondoset offset press and the first ROLAND 800 sheet-fed offset press with ink compensation control system, its printing speed can reach 10,000 sheets per hour, and the launch of COLORMAN, the largest rotary printing press in Europe at the time; in 1974, Heidelberg Launched the first model of a new generation of printing presses – the Speedmaster 72V four-color offset press ; in 1974, KBA (Planeta) launched the world’s first sheet-fed offset press with eight units.   Rapid development   In the mid-1980s, printing plants began to use computers to control the printing process. Most of the offset presses in this era realized automation of ink transfer, dampening, registration adjustment and plate reading, simplifying operations and improving printing efficiency. The application of computers in offset printing and the advent of film output machines have greatly improved the working efficiency of offset printing machines. Many offset printing machines launched in the 1980s were equipped with ink remote control systems, computer-controlled pre-inking systems, dampening unit control, alcohol-free dampening, color control systems, flipping devices, etc. Representative models include Heidelberg GTO52 and Akiyama HA1P40. , Hi-Ace432 and Bestech32, Komori Riselong L40, etc. as examples. It is worth mentioning that in 1985, KBA produced the Rapida 104, the world’s first split sheet-fed offset press with a printing speed of 15,000 sheets/hour.   In the 1990s, the birth of the direct-to-plate system (CTP) was the most important contribution to offset printing technology, bringing the work efficiency and application of offset printing machines to unprecedented levels. Offset presses are more automated and digital technology is more widely used. The highlight of this period was the GTO-DI, the world’s first on-machine direct-to-plate printing press jointly launched by Presstek and Heidelberg at the Print 91 Chicago Print Show, which represented the future development direction of short-run offset printing. At IPEX 98, the Heidelberg Speedmaster SM 74 DI direct imaging offset press was exhibited for the first time and caused a sensation around the world. Today, these configurations may no longer seem new, but at the time it was comparable to laser printers and met the needs of on-demand color printing. Even on drupa 2000, many printing press manufacturers launched their own DI solutions. In 1997, KBA launched the Compacta 215, the world’s first commercial web offset press that fully adopted shaftless technology, which was also an important breakthrough in the development of web offset presses. Since then, shaftless technology has been widely used in web offset presses. Heidelberg CP Window, the world’s first fully digital printing control system, also met users at drupa1990.   At this stage, the offset printing press products launched by major manufacturers have become more mature and complete, and have begun to develop in the direction of multi-color groups and multi-functions, making multi-color group double-sided printing, connected varnishing and drying no longer just a dream. Manroland launched the Roland 700 and Roland 300, medium-sized machines with a printing speed of 15,000 sheets/hour, and the Roland 900, a large-format sheet-fed offset press with an innovative concept; Komori was the first in the world to develop the Komori fully automatic plate changer (Full-APC) ; The new production line of Heidelberg Speedmaster SM74 offset printing press strives to dominate the four-format (52cm × 74cm) printing market; KBA launches the first ten-color (five-to-five) Rapida printing press; Akiyama designs and develops a unique high-performance roller arrangement , high efficiency, high value-added Jprint type sheet-fed double-sided printing press; Komori developed multi-color double-sided offset printing machine LITHRONE 40SP, etc.   Classification   Offset printing machines can be divided into single-color, two-color, four-color and multi-color printing machines according to the number of printing colors completed in one paper pass. According to the maximum paper format that can be printed, it can be divided into small offset printing presses, six-open, four-open, folio and full-sheet printing presses. In addition, there are also double-sided printing presses that can complete two-sided printing at the same time in one paper pass. According to the dampening system, it can be divided into alcohol machine (that is, the offset printing machine with alcohol dampening version), water truck (that is, the offset printing machine with water dampening version) and waterless offset printing machine.   future   The offset printing technology jointly invented by the German Caspar Hermann and the American Ella Washington Roubaix triggered a complete revolution in offset printing technology. This breakthrough enabled the offset printing technology to develop for a hundred years and occupy the entire The printing industry produces 70% of the market. As a technology that has lasted for a hundred years and is constantly improving, the development of offset printing technology is closely related to the development of the global economy and the progress of mankind. A hundred years of history have made it more mature and exciting.    

Pigments(Colorant)

Pigments are substances that give colors to objects. Pigments are divided into soluble and insoluble, inorganic and organic. Inorganic pigments are generally mineral substances. Humans have long known the use of inorganic pigments, using colored earth and ores, to paint on rock walls and smear their bodies. Organic pigments are generally derived from plants and marine animals, such as mozambique, garcinia and purple extracted from shellfish in ancient Rome.   Introduction Pigment is a powdery substance used for coloring. It is insoluble in water, grease, resin, organic solvents and other media, but can be evenly dispersed in these media and can color the media, and has a certain hiding power. The basic requirements for pigments used in art are that the finer the particles, the better, the brighter the color, the better, and the longer it lasts without discoloration, the better (the stability is better). Watercolor paints Watercolor paints, except white, are almost all transparent. Only in this way can the needs of watercolor cover dyeing be met. Gouache paint was originally invented by adding white powder to watercolor paint to make the color opaque. Because watercolor paint is transparent, it is difficult to correct if you make a mistake. Gouache paint can be easily modified because it is opaque. Later, raw materials such as gum arabic were added to the gouache pigment to further improve its performance. Gum arabic can make the surface of gouache paint have a layer of luster after it dries. However, in special occasions where flat coating is required (such as rendering renderings and coloring animations), the glue will form irregular spots on the surface of the color, or make the color dull. It is uneven, so there are special degumming pigments. Oil paint is paint diluted with oil. Chinese painting pigments are very rich and come in various types, ranging from mineral powder to plant extraction to animal extraction, and the types are complex. Theoretically, as long as there are three primary colors of red, blue and yellow, all other colors can be mixed, but the purity of the mixed colors is always not high enough. Therefore, modern art paint manufacturers produce high-purity pigments for various hues and brightness colors. to meet various needs. From the most basic 12 colors to the usual 24 colors or even 48 colors to more than 60 colors. Special metallic colors are not included. use It is an indispensable raw material for the manufacture of paints, inks, oil painting pastes, cosmetic paints, colored papers, etc. It is also used for filling and coloring plastics, rubber products, and synthetic fiber solutions. Performance characteristics Pigments usually have the following properties: color. Color pigments are pigments that selectively absorb and scatter visible light energy and can present colors such as yellow, red, blue, and green under natural light conditions. Tinting power. The ability of a coloring pigment to absorb incident light. It can be expressed as a relative percentage equivalent to the tinting power of a standard pigment sample. Covering power. The ability of a film-forming substance to cover the surface color of a substrate. It is often expressed in grams of pigment contained in paint covering an area of ​​1 square meter. Lightfastness. The ability of pigments to maintain their original color under certain lighting conditions. Generally, an eight-level system is used, with level eight being the best. Weather resistance. The ability of pigments to maintain their original properties under certain natural or artificial climatic conditions. Generally, a five-level system is used, with level five being the best. Volatile. Mainly refers to moisture, which is generally not more than 1%. Oil absorption. Refers to the number of grams of refined linseed oil required to form a uniform mass of 100 grams of pigment. The one with the smallest oil absorption capacity is better. The oil absorption capacity is related to the specific surface area and structure of the pigment particles. water soluble matter. The water-soluble substances contained in the pigment are expressed as a mass percentage of the pigment. The water-soluble content of pigments used in paint making is often controlled below 1%. concept Pigment is a colored fine-grained powdery substance that is generally insoluble in water and can be dispersed in various media such as oils, solvents, and resins. It has hiding power, tinting power, and is relatively stable to light. It is often used in the preparation of coatings, inks, and colored plastics and rubber, so it can also be called a colorant. Pigments differ from dyes in that dyes are generally soluble in water (an old distinction), while pigments are generally insoluble in water. Dyes are mainly used for dyeing textiles and other materials. However, this distinction is not very clear, because some dyes may also be insoluble in water, and pigments are also used in pigment printing and pulp coloring of textiles. The chemical structure of organic pigments is similar to that of organic dyes, so they are usually regarded as a branch of dyes. Performance characteristics Pigments usually have the following properties: color . Color pigments are pigments that selectively absorb and scatter visible light energy and can present colors such as yellow, red, blue, and green under natural light conditions. Tinting power . The ability of a coloring pigment to absorb incident light. It can be expressed as a relative percentage equivalent to the tinting power of a standard pigment sample. Covering power . The ability of a film-forming substance to cover the surface color of a substrate. It is often expressed in grams of pigment contained in paint covering an area of ​​1 square meter. Lightfastness . The ability of pigments to maintain their original color under certain lighting conditions. Generally, an eight-level system is used, with level eight being the best. Weather resistance . The ability of pigments to maintain their original properties under certain natural or artificial climatic conditions. Generally, a five-level system is used, with level five being the best. Volatile . Mainly refers to moisture, which is generally not more than 1%. Oil absorption . Refers to the number of grams of refined linseed oil required to form a uniform mass of 100 grams of pigment. The one with the smallest oil absorption capacity is better. The oil absorption capacity is related to the specific surface area and structure of the pigment particles. water soluble matter . The water-soluble substances contained in the pigment are expressed as a mass percentage of the pigment. The water-soluble content of pigments used in paint making is often controlled below 1%. Basic classification Pigments can be divided into two categories based on their chemical composition: inorganic pigments and organic pigments. Based on their sources, they can be further divided into natural pigments and synthetic pigments. Natural pigments are derived from minerals, such as cinnabar, laterite, realgar, malachite green and heavy calcium carbonate, wollastonite, barite powder, talc powder, mica powder, kaolin, etc. Those from biological sources, such as those from animals: cochineal red, natural fish scale powder, etc.; those from plants include: garcinia, alizarin red, indigo, etc. Synthetic pigments are artificially synthesized, such as inorganic pigments such as titanium white, zinc barium white, lead chromium yellow, and iron blue, as well as organic pigments such as red pink, even light yellow, phthalocyanine blue, and quinacridone. Pigments are classified according to their function, such as anti-rust pigments, magnetic pigments, luminescent pigments, pearlescent pigments, conductive pigments, etc. Classification by color is a convenient and easy-to-use method. Thus pigments can be classified as white, yellow, red, blue, green, brown, purple, black, regardless of their origin or chemical composition. The famous “Dye Index” (ColorIndex) uses a color classification method: for example, pigments are divided into pigment yellow (PY), pigment orange (PO), pigment red (PR), pigment violet (PV), and pigment blue (PB). , Pigment green (PG), Pigment brown (PBr), Pigment black (PBk), Pigment white (PW), Metallic pigment (PM) and other ten categories. Pigments of the same color are arranged according to the sequence number. For example, titanium white is PW- 6. Zinc-barium white PW-5, lead chromium yellow PY-34, quinacridone PR-207, iron oxide red PR-101, phthalocyanine blue PB-15, etc. In order to find the chemical composition, there are other structural numbers, such as titanium white PW-6C.I.77891 and phthalocyanine blue PB-15C.I.74160, which allow manufacturers and users of pigments to identify the listed pigments. The composition and chemical structure of. Therefore, it has been widely used in the international pigment import and export trade industry, and some domestic pigment manufacturers also use this international classification standard for pigments. China’s national standard for pigments, GB/T3182-1995, also uses color classification. Each pigment color has a symbol, such as white for BA, red for HO, yellow for HU… Then combined with the code and serial number of the chemical structure, the pigment model is formed, such as rutile titanium white BA-01-03, medium chrome yellow HU-02-02, iron oxide red HO-01-01, zinc barium white BA-11-01, toluidine red HO-02-01, BGS phthalocyanine blue LA-61-02, etc. Pigments can be classified according to the types of compounds they contain: Inorganic pigments can be subdivided into oxides, chromates, sulfates, silicates, borates, molybdates, phosphates, vanadates, ferricyanates , hydroxides, sulfides, metals, etc.; organic pigments can be divided into azo pigments, phthalocyanine pigments, anthraquinones, indigo, quinacridone, dioxazine and other polycyclic pigments, arylmethane according to the chemical structure of the compound Department of pigments, etc. From the perspective of production and manufacturing, they can be classified into titanium pigments, iron pigments, chromium pigments, lead pigments, zinc pigments, metallic pigments, and organic synthetic pigments. This classification method has practical significance, and often one system can Represents a professional pigment production industry. From the perspective of application, it can be divided into paint pigments, ink pigments, plastic pigments, rubber pigments, ceramic and enamel pigments, pharmaceutical and cosmetic pigments, art pigments, etc. Various specialty pigments have some unique properties to match the requirements of the application. Pigment manufacturers can also recommend a series of pigment products to professional users in a targeted manner. acrylic paint Acrylic paint is a synthetic polymer pigment invented in the 1950s. It is made of pigment powder mixed with acrylic latex. Acrylic latex is also called acrylic resin polymerized latex. There are many kinds of acrylic resins, such as methacrylic resins, etc. Therefore, there are also many kinds of acrylic paints. Foreign pigment manufacturers have produced a series of acrylic products, such as matte acrylic pigments, semi-matte acrylic pigments, glossy acrylic pigments, acrylic matte oils, glazing oils, plastic ointments, etc. Acrylic paints are very popular among painters. Compared with oil paints, it has the following characteristics: 1. It can be released with water to facilitate cleaning. 2. Quick drying. The paint dries within minutes after being put down, unlike oil paintings that have to wait several months to be polished. Painters who prefer slow-drying paints can use retarder to delay the drying time of the paint. 3. The coloring layer quickly loses solubility as it dries, forming a tough, elastic, water-impermeable film. This membrane is similar to rubber. 4. The color is full, thick, and fresh, and it never feels “dirty” or “grey” no matter how you blend it. The colored layer will never absorb oil and cause stains. 5. The longevity of the piece is longer. The oil film in oil paintings is prone to oxidation over time, turning yellow and hardening, which can easily lead to cracks in the painting. Theoretically speaking, acrylic film will never become brittle or yellow. 6. The biggest difference between acrylic paint and oil painting in the way it is used is that it has the operating characteristics of general water-based paints and can be used as both watercolor and gouache. 7. Acrylic modeling ointment contains granular types, and there are coarse particles and fine particles, which provides convenience for making textures. 8. Acrylic paint is not very harmful to the human body. Just be careful not to accidentally eat it. 9. Acrylic paint can be used to design your own cultural shirts, which can highlight your personal personality. But it’s best to use cotton clothes and be white. It should be noted that acrylic painting should be painted on a base made of acrylic primer (GESSO), not an oil base. Material experts also do not advocate the mixing of acrylic and oil paints, especially not to paint oil paintings on an acrylic base. This is mainly for the permanent preservation of the work. There is no adverse reaction between acrylic and oil paints. When used alternately, their adhesion needs to be tested over time. water based pigments Water-based pigment is a new type of environmentally friendly pigment. Compared with traditional pigments, it has the advantages of non-toxic and odorless. Compared with traditional pigments, it is more in line with the concept of health and environmental protection, and has become a trend in pigments. Oil paints Oil paint is a special paint for oil paintings, which is made by mixing and grinding pigment powder with oil and glue. Most of them are sold in the market in tubes, but you can also make your own. Oil paint is a material entity formed by mixing and grinding mineral, plant, animal, chemically synthesized toner and the blending agent linseed oil or walnut oil. Its characteristic is that it can be dyed to other materials or attached to certain materials to form a certain pigment layer. This pigment layer has a certain degree of plasticity. It can form various shapes and marks that the painter wants to achieve according to the use of tools. texture. The various hues of oil paints are determined by the hue of the toner. Oil can make the hue of the toner slightly darker and more saturated. Chinese painting pigments Chinese painting pigments, also called Chinese painting pigments, are special pigments used to paint Chinese paintings. They are generally sold in tubes and paint blocks, but also in pigment powder. Classification of Chinese Painting Pigments Traditional Chinese painting pigments are generally divided into two categories: mineral pigments and plant pigments. Historically speaking, minerals should be used first, followed by plants, just like when using ink, pine smoke comes first and oil smoke comes later. The bright colors left on the ancient rock paintings were found to be made from mineral pigments (such as cinnabar). The remarkable characteristics of mineral pigments are that they are not easy to fade and are brightly colored. Most people who have seen Zhang Daqian’s splash-color paintings in his later years have this impression. , large areas of azurite, azurite, and cinnabar can refresh people’s spirits! Plant pigments are mainly extracted from trees and flowers. gouache paint Gouache is the abbreviation of gouache pigment. It has many names in China, such as advertising color, promotional color, etc. It is a kind of watercolor, that is, opaque watercolor paint. Because it is cheap, easy to learn and use, it is often used as an introductory painting material for beginners to learn color painting, and its usage simulates oil painting techniques. Performance of gouache Limitations of Purity and Brightness of Gouache Color When gouache paint is wet, its color saturation is as high as that of oil paint. But after it dries, due to the effect of the powder and the color losing its luster, the saturation is greatly reduced. This is its color. Limitations of Purity. The brightness of gouache is improved by diluting, adding powder, or using lighter colors with more powdery pigments. Its dry and wet changes are very large. Often some colors only add a small amount of powder. When wet and dry, the brightness will show a darker or lighter difference. This is the dry-wet reaction of gouache paint. Because the color of gouache generally becomes lighter after it dries, using the gouache well is the most difficult problem to solve technically in gouache painting. The pink color just makes the color of the picture full of the unique “pink” quality of gouache painting, and appears particularly rich in the middle color, but the color fineness of gouache painting is still far lower than that of oil painting. Due to the limitations of gouache paint, few large-scale works with higher specifications are created with gouache paint. Personality differences of gouache pigments Most colors of gouache pigments are relatively stable, such as earthy yellow, earthy red, ocher, orange, medium yellow, light yellow, olive green, pink green, ultramarine, cobalt blue, lake blue, etc. However, colors such as deep red, rose red, green lotus, and violet in gouache paint are extremely unstable, prone to color flipping, and difficult to cover. There are few types of transparent gouache colors, only a few colors such as lemon yellow, rose red, and green lotus. To draw a good gouache painting, you must fully grasp the personality of each gouache pigment and understand its color-receiving ability and covering ability. size, color and price. These issues require continuous practice so that practice makes perfect. Limitations of gouache There will be no unevenness when painting a large area. toxicology Regarding the toxicology of organic pigments it can be summarized that the pigments themselves are considered almost physiologically inert (safe), the health effects arise mainly from their dusty state (granular matter), due to their poor solubility. Organic pigments are actually not biodegradable. However, dispersants, binders, solvents, etc. may be used in the intermediate or final products of pigments. Under certain conditions, the toxicological effects of these substances should be considered. Toxicity sometimes results from degradation products. This degradation product of the pigment occurs when it is irradiated with laser light. For example, CI Pigment Red 22, 2-methyl-5-nitroaniline is produced by cleavage of the pigment by laser irradiation and the toxic krebseregende. Naming method Pigments are usually associated with a common name, a trade name or a color index of name (CI Common Name Nomenclature), as systematic nomenclature according to IUPAC (International Union of Pure and Applied Chemistry) or CAS (Chemical Abstracts Society) can result in unwieldy names. example: Common name: tender yellow Product name: Aureolin benzimidazolone yellow Protected Trade Name: Hostaperm Yellow H4G(TM) CI common name: CI Pigment Yellow 151 CAS Index: Benzoic acid, 2-[[1-[[(2,3-dihydro-2-oxo-1H-benzimidazol-5-yl)amino]carbonyl]-2-oxopropyl] Azo]

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