Molecular formula : C2H6O
MW : No. 46.07
CAS production specimen-17-5
nature : a transparent colorless, flammable volatile liquid. Wine is irritating and pungent odor and taste. Dissolved in water, methanol, ether and chloroform. Many can be dissolved organic compounds and some inorganic compounds. With hygroscopicity. With the formation of water azeotropic mixture. Steam and air to form explosive mixtures explosion limit 4.3% -19.0% (volume). Ethanol relative density of 0.7893 (20 / 4 ° C) -117.3 ° C melting point, boiling point of 78.32 ° C, 1.3614 refractive index, the flash point (closed cup) 14 ° C Industrial ethanol (containing 95% ethanol) 1.3651 refractive index, surface tension (20 ° C) 22.8mN / m, viscosity (20 ° C) 1.41mPa s, vapor pressure (20 ° C) 5.732kPa, heat capacity (23 ° C ) 2.58J / (g ° C), a flash point of 12.8 ° C and relative density of 0.816, 78.15 ° C boiling point, freezing point -114 ° C, 793 ° C spontaneous combustion point.
Preparation : 20 1930s before fermentation ethanol is the only industrial production methods. With the petrochemical and rapid development of the synthesis of ethanol production is increasing. But ethanol synthesis heterogeneous mixture of high-carbon alcohol, to the senior role in the nerve center of paralysis, not suitable for beverages, food, medicine and spices. Therefore, even in petrochemical developed countries, ethanol fermentation still occupy a certain percentage. 1. Fermentation of starch-rich agricultural products such as grains, potatoes or wild plants such as fruit washed, crushed, pressure cooking, starch paste, then adds the right amount of water, cooling to 60 ° C by adding about amylase, followed by hydrolysis of starch to glucose and maltose. The mother then joined the enzyme fermentation bacteria obtained ethanol. 2. Legitimate water to water and ethylene as raw materials, through the addition reaction from the system. Water legitimate divided into indirect and direct water legitimate two legitimate water. Indirect water legitimate also called sulfate, two-step reaction. The first 95-98% 50-60% sulfuric acid and ethylene by 2:1 (weight ratio) in the absorption tower reactor response 60-73-80 ° C ,0.78 - 1.96 MPa conditions generated sulfate. The second step is to hydrolysis sulfate in the tower at 80-100 ° C ,0.2 - 0.29 MPa pressure hydrolysis derived ethanol, ethyl ether byproduct formation. En directly with the reactions of ethanol. Water that is a direct one-step legal. Ethylene and water from the phosphate catalyst at high temperature under pressure hydration obtained. This law is simple, corrosive requirement is small, special steel, vice - ether small, but high purity ethylene demand, consumption big. Both the fermentation of water or ethylene legal system of ethanol are usually ethanol and water azeotrope that the concentration of 95% of the ethanol industry. In order to obtain anhydrous ethanol, the following method can be used to further dehydration. (1) to use quicklime industrial ethanol, and water into calcium hydroxide, and then steamed ethanol, reusable metal sodium drying; This is the oldest method. (2) dehydration azeotropic distillation is commonly used industrial methods. (3) ion exchange agent or molecular sieve dehydration, then distillation.
purposes : Ethanol is an important organic solvents widely used in medicine, paint, health supplies, cosmetics, oils and other methods, the total alcohol consumption accounted for 50%. Ethanol is an important basic chemical raw materials, used in the manufacture of acetaldehyde, B diene, triethylamine, ethyl acetate, acetic acid, ethylene oxide, etc., and the derived medicine, dyes, paints, spices, synthetic rubber, detergents, pesticides and other intermediate products of many, as many as 300 types of products above, but ethanol as a chemical intermediate product uses is gradually declining, many products such as acetaldehyde, acetic acid, ethyl alcohol are no longer used for ethanol and other raw materials instead of raw materials. 75% ethanol solution with strong bactericidal and is commonly used disinfectants. After refining the specialized ethanol can be used in the manufacture of beverages. Similar with methanol, ethanol for energy use. Some countries have begun to separate ethanol as vehicle fuel or gasoline-doped (10%) used to conserve gasoline.
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