Usual impurities of fermentation alcohol are fusel oils (mainly higher alcohols, especially pentanols), aldehydes, esters, ketones and water. With synthetic alcohol, likely impurities are water, aldehydes, aliphatic esters, acetone and diethyl ether. Traces of *benzene are present in ethanol that has been dehydrated by azeotropic distillation with *benzene. Anhydrous ethanol is very hygroscopic. Water (down to 0.05%) can be detected by formation of a voluminous precipitate when aluminium ethoxide in *benzene is added to a test portion, Rectified spirit (95% ethanol) is converted to absolute (99.5%) ethanol by refluxing with freshly ignited CaO (250g/L) for 6hours, standing overnight and distilling with precautions to exclude moisture. Numerous methods are available for further drying of absolute ethanol for making “Super dry ethanol”. Lund and Bjerrum [Chem Ber 64 210 1931] used reaction with magnesium ethoxide, prepared by placing 5g of clean dry magnesium turnings and 0.5g of iodine (or a few drops of CCl4), to activate the Mg, in a 2L flask, followed by 50-75 mL of absolute ethanol, and warming the mixture until a vigorous reaction occurs. When this subsides, heating is continued until all the magnesium is converted to magnesium ethoxide. Up to 1L of ethanol is then added and, after an hour's reflux, it is distilled off. The water content should be below 0.05%. Walden, Ulich and Laun [Z Phys Chem 114 275 1925] used amalgamated aluminium chips, prepared by degreasing aluminium chips (by washing with Et2O and drying in a vacuum to remove grease from machining the Al), treating with alkali until hydrogen evolved vigorously, washing with H2O until the washings were weakly alkaline and then stirring with 1% HgCl2 solution. After 2minutes, the chips were washed quickly with H2O, then alcohol, then ether, and dried with filter paper. (The amalgam became warm.) These chips were added to the ethanol, which was then gently warmed for several hours until evolution of hydrogen ceased. The alcohol was distilled and aspirated for some time with pure dry air. Smith [J Chem Soc 1288 1927] reacted 1L of absolute ethanol in a 2L flask with 7g of clean dry sodium, and added 25g of pure ethyl succinate (27g of pure ethyl phthalate was an alternative), and refluxed the mixture for 2hours in a system protected from moisture, and then distilled the ethanol. A modification used 40g of ethyl formate instead, so that sodium formate separated out and, during reflux, the excess of ethyl formate decomposed to CO and ethanol. Drying agents suitable for use with ethanol include Linde type 4A molecular sieves, calcium metal, and CaH2. The calcium hydride (2g) is crushed to a powder and dissolved in 100mL absolute ethanol by gently boiling. About 70mL of the ethanol are distilled off to remove any dissolved gases before the remainder is poured into 1L of ca 99.9% ethanol in a still, where it is boiled under reflux for 20hours, while a slow stream of pure, dry hydrogen (better use nitrogen or Ar) is passed through. It is then distilled [Rüber Z Elektrochem 29 334 1923]. If calcium is used for drying, about ten times the theoretical amount should be used, and traces of ammonia (from some calcium nitride in the Ca metal) would be removed by passing dry air into the vapour during reflux. Ethanol can be freed from traces of basic materials by distillation from a little 2,4,6-trinitrobenzoic acid or sulfanilic acid. *Benzene can be removed by fractional distillation after adding a little water (the *benzene/water/ethanol azeotrope distils at 64.9o), the alcohol is then re-dried using one of the methods described above. Alternatively, careful fractional distillation can separate *benzene as the *benzene/ethanol azeotrope (b 68.2o). Aldehydes can be removed from ethanol by digesting with 8-10g of dissolved KOH and 5-10g of aluminium or zinc per L, followed by distillation. Another method is to heat under reflux with KOH (20g/L) and AgNO3 (10g/L) or to add 2.5-3g of lead acetate in 5mL of water to 1L of ethanol, followed (slowly and without stirring) by 5g of KOH in 25mL of ethanol: after 1hour the flask is shaken thoroughly, then set aside overnight before filtering and distilling. The residual water can be removed by standing the distillate over activated aluminium amalgam for 1 week, then filtering and distilling. Distillation of ethanol from Raney nickel eliminates catalyst poisons. Other purification procedures include pre-treatment with conc H2SO4 (3mL/L) to eliminate amines, and with KMnO4 to oxidise aldehydes, followed by refluxing with KOH to resinify aldehydes, and distilling to remove traces of H3PO4 and other acidic impurities after passage through silica gel, and drying over CaSO4. Water can be removed by azeotropic distillation with dichloromethane (azeotrope boils at 38.1o and contains 1.8% water) or 2,2,4-trimethylpentane. [Beilstein 1 IV 1289.] Rapid purification: Place degreased Mg turnings (grease from machining the turnings is removed by washing with dry EtOH then Et2O, and drying in a vacuum) (5g) in a dry 2L round bottomed flask fitted with a reflux condenser (protect from air with a drying tube filled with CaCl2 or KOH pellets) and flush with dry N2. Then add iodine crystals (0.5g) and gently warm the flask until iodine vapour is formed and coats the turnings. Cool, then add EtOH (50mL) and carefully heat to reflux until the iodine disappears. Cool again then add more EtOH (to 1L) and reflux under N2 for several hours. Distil and store over 3A molecular sieves (pre-heated at
Ethanol has been known to humans since prehistory as the active ingredient of alcoholic beverages. Its isolation as a relatively pure compound was probably achieved first by Islamic alchemists who developed the art of distillation.
Ethanol is widely used for its solvent and antiseptic
properties. It is rather an irritant and sensitization has
rarely been reported.
Ethanol, also known as ethyl alcohol (or grain spirits, or alcohol), is a clear colorless, volatile, flammable solvent with a characteristic odor. The boiling point of ethanal is 78.5°C. The bio-alcohol is found in alcoholic beverages. Concentrated alcohol has a strong burning taste, but it is somewhat sweet when diluted. It is also increasingly being used as a fuel (usually replacing or complementing gasoline). Its low melting point of -114.5° C allows it to be used in antifreeze products.
Suitable for use in the precipitation of nucleic acids.
A solution of 70-85% of ethanol is commonly used as a disinfectant and it kills organisms by denaturing their proteins and dissolving their lipids. It is effective against most bacteria and fungi, and many viruses, but is ineffective against bacterial spores. This disinfectant property of ethanol is the reason that alcoholic beverages can be stored for a long time. Ethanol also has many medical uses, and can be found in products such as medicines, medical wipes and as an antiseptic in most antibacterial hand sanitizer gels. Ethanal can also be used as antidote. It competitively blocks the formation of toxic metabolites in toxic alcohol ingestions by having a higher affinity for the enzyme Alcohol Dehydrogenase (ADH). Its chief application is in methanol and ethylene glycol ingestions. Ethanol can be administered by the oral, nasogastric or intravenous route to maintain a blood ethanol concentration of 100-150 mg/dl (22-33 mol/L).
Ethanol is flammable and burns more cleanly than many other fuels. Ethanol has been used in cars since Henry Ford designed his 1908 Model T to operate on alcohol. In Brazil and the United States, the use of ethanol from sugar cane and grain as car fuel has been promoted by government programs. The Brazilian ethanol program started as a way to reduce the reliance on oil imports, but it was soon realized that it had important environmental and social benefits. The fully combusted products of ethanol are only carbon dioxide and water. For this reason, it is environmental friendly and has been used to fuel public buses in the US. However, pure ethanol attacks certain rubber and plastic materials and cannot be used in unmodified car engines.
The alcohol-based alternative fuel that is blended with gasoline to produce a fuel with a higher octane rating and fewer harmful emissions than unblended gasoline. A mixture containing gasoline with at least 10% ethanol is known as gasohol. Specifically, gasoline with 10% ethanol content is known as E10. Another common gasohol variant is E15, which contains 15% ethanol and 85% gasoline. E15 is only appropriate for use in Flex Fuel vehicles or a very small percentage of the newest vehicles. In addition, E85 is a term used for a mixture of 15% gasoline and 85% ethanol. E85 keeps the fuel system clean because it burns cleaner than regular gas or diesel and doesn't leave behind gummy deposits. Beginning with the model year 1999, a number of vehicles in the U.S. were manufactured so as to be able to run on E85 fuel without modification. These vehicles are often labeled dual fuel or flexible fuel vehicles, since they can automatically detect the type of fuel and change the engine's behavior to compensate for the different ways that they burn in the engine cylinders.
The use of ethanol-diesel fuel blends is growing around the world, and are designed to provide renewable, cleaner burning fuel alternatives for off-road equipment, buses, semi-trucks and other vehicles that run on diesel fuel. With the addition of ethanol and other fuel additives to diesel, the characteristic black diesel smoke is eliminated and there are significant reductions in particulate matter, carbon monoxide, and nitrogen oxide emissions. It is also possible to use ethanol for cooking as a replacement for wood, charcoal, propane, or as a substitute for lighting fuels, such as kerosene.
Brazil and the United States lead the industrial production of ethanol fuel, accounting together for 89% of the world's production in 2008. In comparison with the USA and Brazil, Europe ethanol for fuel production is still very modest. Brazil is the world's second largest producer of ethanol fuel and the world's largest exporter.
Significant volumes of ethanol are produced for the beverage and industrial markets from agricultural feedstock. Ethanol produced for these industries differs from ethanol for fuel only in its strength, which can vary between 96% and 99.9% and in its purity, depending on the end use. Beverage and drinks industry may be the best-known end-user of ethanol. It is used to make many kinds of spirits, such vodka, gin and anisette. High standards and processes are required for ethanal used in the production of spirit drinks.
The ethanol used as an intermediary product by the chemical, pharmaceutical or cosmetics industry is in many cases of the highest and purest possible quality. These are premium markets due to the additional steps in the alcohol production process that are necessary to achieve the required purity. Same high standards and purity requirements apply in food industry, such as flavors and aromas extraction and concentrations, as well as paints and thermometers. Ethanol can be used in de-icer or anti-freeze to clear the car windscreen. It also is contained in perfumes, deodorants, and other cosmetics.
VAPOR: Irritating to eyes, nose and throat. LIQUID: Not harmful.
Ethanol is produced by fermenting and distilling grains. Actually, ethanol can be made from any plant that contains a large amount of sugar or components that can be converted into sugar, such as starch or cellulose. As their names imply, sugar beets and sugar cane contain natural sugar. Crops such as corn, wheat and barley contain starch that can be easily converted to sugar. Today, ethanol is made primarily from corn.
Another form of ethanol, called bioethanol, can be made from lignocellulosics which are from many types of trees and grasses, although the process is more difficult. Lignocellulose consists of three main components: cellulose, hemicellulose and lignin, the first two being composed of chains of sugar molecules. Those chains can be hydrolyzed to produce monomeric sugars, some of which can be fermented using yeasts to produce ethanol. Ethanol can be produced from lignocellulosic materials in various ways, but all processes comprise the same main components: hydrolysis of the hemicellulose and the cellulose to monomer sugars, fermentation and product recovery and concentration by distillation.
Currently, ethanol production processes using crops are well-established. However, utilization of a cheaper substrate, such as lignocellulose, could make bioethanol more competitive with fossil fuel. Therefore, bacterial and yeast strains have been constructed which are advantageous for ethanol production. The cost of ethanol production from lignocellulosic materials is relatively high based on current technologies, and the main challenges are the low yield and high cost of the hydrolysis process. Considerable research efforts have been made to improve the hydrolysis of lignocellulosic materials. Besides, new enzymes have revolutionized the liquefaction process in starch ethanol and improved ethanol yield and product quality.
ChEBI: A primary alcohol that is ethane in which one of the hydrogens is substituted by a hydroxy group.
Safety and hazards
Even though ethanol is very commonly used, it is a dangerous chemical. As ethanal is highly flammable, it has exact flash points which needs to be noticed. While ethanol is consumed when drinking alcoholic beverages, consuming ethanol alone can cause coma and death. Ethanol may also be a carcinogenic.
Exposure to ethanol can be in vapor form (breathing it in), skin/body contact or ingestion. All are serious and need to be managed appropriately to ensure more damage is not incurred while trying to attend to the exposure.
Common side effects of ethanol include: intoxication, low blood pressure (hypotension) with flushing, agitation, low blood sugar (hypoglycemia), nausea, vomiting and excessive urination.
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 J. Zaldivar, J. Nielsen, L. Olsson, Fuel ethanol production from lignocellulose: a challenge for metabolic engineering and process integration, Applied microbiology and biotechnology, 56(2001) 17-34.
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Most ethyl alcohol is used in alcoholic beverages in suitable dilutions. Other uses are as solvent in laboratory and industry, in the manufacture of denatured alcohol, pharmaceuticals (rubbing Compounds, lotions, tonics, colognes), in perfumery, in organic synthesis. Octane booster in gasoline. Pharmaceutic aid (solvent).
FLAMMABLE. Flashback along vapor trail may occur. Vapor may explode if ignited in an enclosed area.
Ethanol is highly soluble in water and organic solvents, but poorly soluble in fats and oils. Ethanol itself is a good solvent, which is used in cosmetics, paints and tinctures. Density of ethanol at 68 °F (20 °C) is 789 g/l. Pure ethanol is neutral (pH ~7). Most alcoholic beverages are more or less acidic.
Ethanol/ethyl alcohol is highly flammable liquid, hygroscopic, and fully miscible in water. Ethanol is incompatible with a large number of chemicals such as strong oxidising agents, acids, alkali metals, ammonia, hydrazine, peroxides, sodium, acid anhydrides, calcium hypochlorite, chromyl chloride, nitrosyl perchlorate, bromine pentafluoride, perchloric acid, silver nitrate, mercuric nitrate, potassium tert-butoxide, magnesium perchlorate, acid chlorides, platinum, uranium hexafluoride, silver oxide, iodine heptafluoride, acetyl bromide, disulphuryl difluoride, acetyl chloride, permanganic acid, ruthenium (VIII) oxide, uranyl perchlorate, and potassium dioxide.