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Ethanol

2007 Schools Wikipedia Selection. Related subjects: Chemical compounds

                         Ethanol
                     Ethanol Ethanol
                         General
   Systematic name        Ethanol
   Other names            Ethyl alcohol,
                          grain alcohol,
                          hydroxyethane,
                          EtOH
   Molecular formula      C[2]H[6]O
   SMILES                 CCO
   Molar mass             46.06844(232) g/mol
   Appearance             colourless clear liquid
   CAS number             [64-17-5]
                        Properties
   Density and phase      0.789 g/cm³, liquid
   Solubility in water    Fully miscible
   Melting point          −114.3 °C (158.8 K)
   Boiling point          78.4 °C (351.6 K)
   Acidity (pK[a])        15.9 (H^+ from OH group)
   Viscosity              1.200 c P at 20 °C
   Dipole moment          1.69 D (gas)
                         Hazards
   MSDS                   External MSDS
   EU classification      Flammable (F)
   NFPA 704

                          3
                          0
                          0

   R-phrases              R11
   S-phrases              S2, S7, S16
   Flash point            13 °C (55.4 °F)
   RTECS number           KQ6300000
                 Supplementary data page
   Structure & properties n, ε[r], etc.
   Thermodynamic data     Phase behaviour
                          Solid, liquid, gas
   Spectral data          UV, IR, NMR, MS
                    Related compounds
   Related alcohols       Methanol, 1-Propanol
   Other heteroatoms      Ethylamine, Ethyl chloride,
                          Ethyl bromide, Ethanethiol
   Substituted ethanols   Ethylene glycol, Ethanolamine,
                          2-Chloroethanol
   Other compounds        Acetaldehyde, Acetic acid
     Except where noted otherwise, data are given for
   materials in their standard state (at 25°C, 100 kPa)
   Infobox disclaimer and references

   Ethanol, also known as ethyl alcohol or grain alcohol, is a flammable,
   colorless, mildly toxic chemical compound with a distinctive
   perfume-like odour, and is the alcohol found in alcoholic beverages. In
   common usage, it is often referred to simply as alcohol. Its molecular
   formula is variously represented as EtOH, C[2]H[5]OH or as its
   empirical formula C[2]H[6]O.

History

   Ethanol has been used by humans since prehistory as the intoxicating
   ingredient in alcoholic beverages. Dried residues on 9000-year-old
   pottery found in northern mainland China imply the use of alcoholic
   beverages even among Neolithic peoples. Its isolation as a relatively
   pure compound was first achieved by Persian alchemists who developed
   the art of distillation during the Abbasid caliphate, the most notable
   of whom was Al-Razi. The writings attributed to Jabir Ibn Hayyan
   (Geber) (721-815) mention the flammable vapors of boiled wine. Al-Kindī
   (801-873) unambiguously described the distillation of wine.
   Distillation of ethanol from water yields a product that is at most
   95.6% ethanol, because ethanol forms an azeotrope with water. Absolute
   ethanol was first obtained in 1796 by Johann Tobias Lowitz, by
   filtering distilled ethanol through charcoal.

   Antoine Lavoisier described ethanol as a compound of carbon, hydrogen,
   and oxygen, and in 1808, Nicolas-Théodore de Saussure determined
   ethanol's chemical formula, and fifty years later, in 1858, Archibald
   Scott Couper published a structural formula for ethanol: this places
   ethanol among the first chemical compounds to have their chemical
   structures determined.

   Ethanol was first prepared synthetically in 1826, through the
   independent efforts of Henry Hennel in Great Britain and S.G. Sérullas
   in France. Michael Faraday prepared ethanol by the acid-catalysed
   hydration of ethylene in 1828, in a process similar to that used for
   industrial ethanol synthesis today.

   Ethanol served as lamp fuel in pre-Civil War United States and helped
   power early Model T automobiles. But the fuel couldn't compete with the
   low cost and availability of petroleum, and ethanol faded from the
   public eye. The recent rise in oil prices has spurred renewed interest.

Physical properties

   Ethanol's hydroxyl group is able to participate in hydrogen bonding. At
   the molecular level, liquid ethanol consists of hydrogen-bonded pairs
   of ethanol molecules; this phenomenon renders ethanol more viscous and
   less volatile than less polar organic compounds of similar molecular
   weight. In the vapor phase, there is little hydrogen bonding; ethanol
   vapor consists of individual ethanol molecules.

   Ethanol has a refractive index of 1.3614.

   Ethanol is a versatile solvent. It is miscible with water and with most
   organic liquids, including nonpolar liquids such as aliphatic
   hydrocarbons. Organic solids of low molecular weight are usually
   soluble in ethanol. Among ionic compounds, many monovalent salts are at
   least somewhat soluble in ethanol, with salts of large, polarizable
   ions being more soluble than salts of smaller ions. Most salts of
   polyvalent ions are practically insoluble in ethanol.

   Furthermore, ethanol is used as a solvent in dissolving medicines, food
   flavourings and colourings that do not dissolve easily in water. Once
   the non-polar material is dissolved in the ethanol, water can be added
   to prepare a solution that is mostly water. The ethanol molecule has a
   water-loving ( hydrophilic) -OH group that helps it dissolve polar
   molecules and ionic substances. The short, water-fearing ( hydrophobic)
   hydrocarbon chain CH[3]CH[2]- can attract non-polar molecules. Thus
   ethanol can dissolve both polar and non-polar substances.

   Several unusual phenomena are associated with mixtures of ethanol and
   water. Ethanol-water mixtures have less volume than their individual
   components: a mixture of equal volumes ethanol and water has only 95.6%
   of the volume of equal parts ethanol and water, unmixed. The addition
   of even a few percent of ethanol to water sharply reduces the surface
   tension of water. This property partially explains the tears of wine
   phenomenon: when wine is swirled inside a glass, ethanol evaporates
   quickly from the thin film of wine on the wall of the glass. As its
   ethanol content decreases, its surface tension increases, and the thin
   film beads up and runs down the glass in channels rather than as a
   smooth sheet.

Chemistry

   Chemical formula of ethanol, (C is carbon, the dash is a single bond, H
   is hydrogen, O is oxygen)
   Enlarge
   Chemical formula of ethanol, (C is carbon, the dash is a single bond, H
   is hydrogen, O is oxygen)

   The chemistry of ethanol is largely that of its hydroxyl group.

   Acid-base chemistry

   Ethanol's hydroxyl proton is very weakly acidic; it is an even weaker
   acid than water. Ethanol can be quantitatively converted to its
   conjugate base, the ethoxide ion (CH[3]CH[2]O^−), by reaction with an
   alkali metal such as sodium. This reaction evolves hydrogen gas:

          2CH[3]CH[2]OH + 2Na → 2CH[3]CH[2]ONa + H[2]

   Nucleophilic substitution

   In aprotic solvents, ethanol reacts with hydrogen halides to produce
   ethyl halides such as ethyl chloride and ethyl bromide via nucleophilic
   substitution:

          CH[3]CH[2]OH + HCl → CH[3]CH[2]Cl + H[2]O

          CH[3]CH[2]OH + HBr → CH[3]CH[2]Br + H[2]O

   Ethyl halides can also be produced by reacting ethanol by more
   specialized halogenating agents, such as thionyl chloride for preparing
   ethyl chloride, or phosphorus tribromide for preparing ethyl bromide.

   Esterification

   Under acid-catalysed conditions, ethanol reacts with carboxylic acids
   to produce ethyl esters and water:

          RCOOH + HOCH[2]CH[3] → RCOOCH[2]CH[3] + H[2]O

   The reverse reaction, hydrolysis of the resulting ester back to ethanol
   and the carboxylic acid, limits the extent of reaction, and high yields
   are unusual unless water can be removed from the reaction mixture as it
   is formed. Esterification can also be carried out using more a reactive
   derivative of the carboxylic acid, such as an acyl chloride or acid
   anhydride.

   Ethanol can also form esters with inorganic acids. Diethyl sulfate and
   triethyl phosphate, prepared by reacting ethanol with sulfuric and
   phosphoric acid, respectively, are both useful ethylating agents in
   organic synthesis. Ethyl nitrite, prepared from the reaction of ethanol
   with sodium nitrite and sulfuric acid, was formerly a widely-used
   diuretic.

   Dehydration

   Strong acids, such as sulfuric acid, can catalyse ethanol's dehydration
   to form either diethyl ether or ethylene:

          2 CH[3]CH[2]OH → CH[3]CH[2]OCH[2]CH[3] + H[2]O

          CH[3]CH[2]OH → H[2]C=CH[2] + H[2]O

   Which product, diethyl ether or ethylene, predominates depends on the
   precise reaction conditions.

   Oxidation

   Ethanol can be oxidized to acetaldehyde, and further oxidized to acetic
   acid. In the human body, these oxidation reactions are catalysed by
   enzymes. In the laboratory, aqueous solutions of strong oxidizing
   agents, such as chromic acid or potassium permanganate, oxidize ethanol
   to acetic acid, and it is difficult to stop the reaction at
   acetaldehyde at high yield. Ethanol can be oxidized to acetaldehyde,
   without overoxidation to acetic acid, by reacting it with pyridinium
   chromic chloride.

   Combustion

   Ethanol combusting in the confines of an evaporating dish
   Enlarge
   Ethanol combusting in the confines of an evaporating dish

   Combustion of ethanol forms carbon dioxide and water:

          C[2]H[5]OH + 3 O[2] → 2 CO[2] +3 H[2]O

Production

   94% denatured ethanol sold in a bottle for household use
   Enlarge
   94% denatured ethanol sold in a bottle for household use

   Ethanol is produced both as a petrochemical, through the hydration of
   ethylene, and biologically, by fermenting sugars with yeast.

Ethylene hydration

   Ethanol for use as industrial feedstock is most often made from
   petrochemical feedstocks, typically by the acid- catalyzed hydration of
   ethene, represented by the chemical equation

          C[2]H[4] + H[2]O → CH[3]CH[2]OH

   The catalyst is most commonly phosphoric acid, adsorbed onto a porous
   support such as diatomaceous earth or charcoal; this catalyst was first
   used for large-scale ethanol production by the Shell Oil Company in
   1947. Solid catalysts, mostly various metal oxides, have also been
   mentioned in the chemical literature.

   In an older process, first practiced on the industrial scale in 1930 by
   Union Carbide, but now almost entirely obsolete, ethene was hydrated
   indirectly by reacting it with concentrated sulfuric acid to product
   ethyl sulfate, which was then hydrolysed to yield ethanol and
   regenerate the sulfuric acid:

          C[2]H[4] + H[2]SO[4] → CH[3]CH[2]SO[4]H

          CH[3]CH[2]SO[4]H + H[2]O → CH[3]CH[2]OH + H[2]SO[4]

Fermentation

   Ethanol for use in alcoholic beverages, and the vast majority of
   ethanol for use as fuel, is produced by fermentation: when certain
   species of yeast (most importantly, Saccharomyces cerevisiae)
   metabolize sugar in the absence of oxygen, they produce ethanol and
   carbon dioxide. The overall chemical reaction conducted by the yeast
   may be represented by the chemical equation

          C[6]H[12]O[6] → 2 CH[3]CH[2]OH + 2 CO[2]

   The process of culturing yeast under conditions to produce alcohol is
   referred to as brewing. Brewing can only produce relatively dilute
   concentrations of ethanol in water; concentrated ethanol solutions are
   toxic to yeast. The most ethanol-tolerant strains of yeast can survive
   in up to about 25% ethanol (by volume).

   During the fermentation process, it is important to prevent oxygen
   getting to the ethanol, since otherwise the ethanol would be oxidised
   to acetic acid (vinegar). Also, in the presence of oxygen, the yeast
   would undergo aerobic respiration to produce just carbon dioxide and
   water, without producing ethanol.

   In order to produce ethanol from starchy materials such as cereal
   grains, the starch must first be broken down into sugars. In brewing
   beer, this has traditionally been accomplished allowing the grain to
   germinate, or malt. In the process of germination, the seed produces
   enzymes that can break its starches into sugars. For fuel ethanol, this
   hydrolysis of starch into glucose is accomplished more rapidly by
   treatment with dilute sulfuric acid, fungal amylase enzymes, or some
   combination of the two.

   At petroleum prices like those that prevailed through much of the
   1990s, ethylene hydration was a decidedly more economical process than
   fermentation for producing purified ethanol. Recent increases in
   petroleum prices, coupled with perennial uncertainty in agricultural
   prices, make forecasting the relative production costs of fermented
   versus petrochemical ethanol difficult at the present time.

Purification

   Near infrared spectrum of liquid ethanol.
   Enlarge
   Near infrared spectrum of liquid ethanol.

   The product of either ethylene hydration or brewing is an ethanol-water
   mixture. For most industrial and fuel uses, the ethanol must be
   purified. Fractional distillation can concentrate ethanol to 95.6%
   volume; the mixture of 95.6% ethanol and 4.4% water (percentage by
   weight) is an azeotrope with a boiling point of 78.2 °C, and cannot be
   further purified by distillation. Therefore, 95% ethanol in water is a
   fairly common solvent.

   After distillation ethanol can be further purified by "drying" it using
   lime or salt. Lime, ( calcium oxide), when mixed with the water in
   ethanol will form calcium hydroxide, which then can be separated. Dry
   salt will dissolve some of the water content of the ethanol as it
   passes through, leaving a purer alcohol.

   Several approaches are used to produce absolute ethanol. The
   ethanol-water azeotrope can be broken by the addition of a small
   quantity of benzene. Benzene, ethanol, and water form a ternary
   azeotrope with a boiling point of 64.9 °C. Since this azeotrope is more
   volatile than the ethanol-water azeotrope, it can be fractionally
   distilled out of the ethanol-water mixture, extracting essentially all
   of the water in the process. The bottoms from such a distillation is
   anhydrous ethanol, with several parts per million residual benzene.
   Benzene is toxic to humans, and cyclohexane has largely supplanted
   benzene in its role as the entrainer in this process.

   Alternatively, a molecular sieve can be used to selectively absorb the
   water from the 95.6% ethanol solution. Synthetic zeolite in pellet form
   can be used, as well as a variety of plant-derived absorbents,
   including cornmeal, straw, and sawdust. The zeolite bed can be
   regenerated essentially an unlimited number of times by drying it with
   a blast of hot carbon dioxide. Cornmeal and other plant-derived
   absorbents cannot readily be regenerated, but where ethanol is made
   from grain, they are often available at low cost. Absolute ethanol
   produced this way has no residual benzene, and can be used as fuel, or,
   when diluted, can even be used to fortify port and sherry in
   traditional winery operations.

   At pressures less than atmospheric pressure, the composition of the
   ethanol-water azeotrope shifts to more ethanol-rich mixtures, and at
   pressures less than 70 torr (9.333 kPa) , there is no azeotrope, and it
   is possible to distill absolute ethanol from an ethanol-water mixture.
   While vacuum distillation of ethanol is not presently economical,
   pressure-swing distillation is a topic of current research. In this
   technique, a reduced-pressure distillation first yields an
   ethanol-water mixture of more than 95.6% ethanol. Then, fractional
   distillation of this mixture at atmospheric pressure distills off the
   95.6% azeotrope, leaving anhydrous ethanol at the bottoms.

Prospective technologies

   Glucose for fermentation into ethanol can also be obtained from
   cellulose. Until recently, however, the cost of the cellulase enzymes
   that could hydrolyse cellulose has been prohibitive. The Canadian firm
   Iogen brought the first cellulose-based ethanol plant on-stream in
   2004. The primary consumer thus far has been the Canadian government,
   which, along with the United States government (particularly the
   Department of Energy's National Renewable Energy Laboratory), has
   invested millions of dollars into assisting the commercialization of
   cellulosic ethanol. Realization of this technology would turn a number
   of cellulose-containing agricultural byproducts, such as corncobs,
   straw, and sawdust, into renewable energy resources.

   Cellulosic materials typically contain, in addition to cellulose, other
   polysaccharides, including hemicellulose. When hydrolysed,
   hemicellulose breaks down into mostly five-carbon sugars such as
   xylose. S. cerevisiae, the yeast most commonly used for ethanol
   production, cannot metabolize xylose. Other yeasts and bacteria are
   under investigation to metabolize xylose and so improve the ethanol
   yield from cellulosic material.

   The anaerobic bacterium Clostridium ljungdahlii, recently discovered in
   commercial chicken wastes, can produce ethanol from single-carbon
   sources including synthesis gas, a mixture of carbon monoxide and
   hydrogen that can be generated from the partial combustion of either
   fossil fuels or biomass. Use of these bacteria to produce ethanol from
   synthesis gas has progressed to the pilot plant stage at the BRI Energy
   facility in Fayetteville, Arkansas; in the BRI process, the heat
   released by gasification can be used to co-produce electricity with
   ethanol.

   Another prospective technology is the closed-loop ethanol plant.
   Ethanol produced from corn has a number of critics who suggest that it
   is primarily just recycled fossil fuels because of the energy required
   to grow the grain and convert it into ethanol. However, the closed-loop
   ethanol plant attempts to address this criticism. In a closed-loop
   plant, the energy for the distillation comes from fermented manure,
   produced from cattle that have been fed the by-products from the
   distillation. The leftover manure is then used to fertilize the soil
   used to grow the grain. Such a process is expected to have a much lower
   fossil fuel requirement.

Ethanol

Denatured alcohol

   In most jurisdictions, the sale of ethanol, as a pure substance, or in
   the form of alcoholic beverages, is heavily taxed. In order to relieve
   non-beverage industries of this tax burden, governments specify
   formulations for denatured alcohol, which consists of ethanol blended
   with various additives to render it unfit for human consumption. These
   additives, called denaturants, are generally either toxic (such as
   methanol) or have unpleasant tastes or odours (such as denatonium
   benzoate).

   Specialty denatured alcohols are denatured alcohol formulations
   intended for a particular industrial use, containing denaturants chosen
   so as not to interfere with that use. While they are not taxed,
   purchasers of specialty denatured alcohols must have a
   government-issued permit for the particular formulation they use and
   must comply with other regulations.

   Completely denatured alcohols are formulations that can be purchased
   for any legal purpose, without permit, bond, or other regulatory
   compliance. It is intended that it be difficult to isolate a product
   fit for human consumption from completely denatured alcohol. For
   example, the completely denatured alcohol formulation used in the
   United Kingdom contains (by volume) 89.66% ethanol, 9.46% methanol,
   0.50% pyridine, 0.38% naphtha, and is dyed purple with methyl violet.

Hydrous and anhydrous ethanol

   Hydrous and anhydrous ethanol are terms used to describe ethanol by the
   type of process used to covert biomass into fuel. There are different
   prices for each anhydrous and hydrous ethanol depending on market
   demands.

   The term hydrous pyrolysis is sometimes used to encompass thermolysis
   in the presence of water, such as steam cracking of oil, or more
   generally hydrous pyrolysis. An example of the latter is thermal
   depolymerization of organic waste into light crude oil.

   Anhydrous (without water) pyrolysis can be used to produce liquid fuel
   similar to diesel from solid biomass. The most common technique uses
   very low residence times (<2 seconds) and high heating rates using a
   temperature between 350-500 °C. It is called either fast or flash
   pyrolysis.'

   Anhydrous Alcohol can also be produced from hydrous(95-96%) alcohol
   using drying agents like molecular sieves, or by azeotropic
   distillation, extractive distillation techniques.

Absolute ethanol

   Absolute or anhydrous alcohol generally refers to purified ethanol,
   containing no more than one percent water.

   It is not possible to obtain absolute alcohol by simple fractional
   distillation, because a mixture containing around 95.6% alcohol and
   4.4% water becomes a constant boiling mixture (an azeotropic mixture).
   In one common industrial method to obtain 100% pure alcohol, a small
   quantity of benzene is added to rectified spirit and the mixture is
   then distilled. Absolute alcohol is obtained in third fraction that
   distills over at 78.2 °C (351.3 K).

   Because a small amount of the benzene used remains in the solution,
   absolute alcohol produced by this method is not suitable for
   consumption as benzene is carcinogenic.

   There is also an absolute alcohol production process by desiccation
   using glycerol. Alcohol produced by this method is known as
   spectroscopic alcohol - so called because the absence of benzene makes
   it suitable as a solvent in spectroscopy.

   Currently, the most popular method of purification past 95.6% purity is
   desiccation using adsorbents such as starch or zeolites. These adsorb
   water preferentially.

Feedstocks

   Currently the main feedstock in the United States for the production of
   ethanol is corn (see the Renewable Fuels Association's list of U.S.
   ethanol for a complete list and feedstock utilized. Approximately 2.8
   gallons of ethanol are produced from one bushel of corn. While much of
   the corn turns into ethanol, some of the corn also yields by-products
   such as DDGS (distillers dried grains with solubles) that can be used
   to fullfill a portion of the diet of livestock. A bushel of corn
   produces about 18 pounds of DDGS ).

   Trials of a new crop, switchgrass, are showing much greater yields.

   The dominant ethanol feedstock in warmer regions is sugarcane.

   In some parts of Europe, particularly France and Italy, wine is used as
   a feedstock due to massive oversupply.

Use

As a fuel

   The largest single use of ethanol is as a motor fuel and fuel additive.
   The largest national fuel ethanol industries exist in Brazil (all fuel
   sold in Brazil contains at least 20% ethanol). One method of production
   is through fermentation of sugar. Ethanol creates very little pollution
   when being burned.However, the production process is actually more
   detrimental to the environment. Millions more acres of land are needed
   if ethanol is to be used to replace gasoline. Pure ethanol has a lower
   energy content than gasoline (about 30% less energy per unit volume).
   At gas stations, ethanol is contained in a mix of ethanol and gasoline,
   otherwise known as gasohol. In the United States, the color yellow
   (symbolizing the colour of corn) has become associated with the fuel
   and is commonly used on fuel pumps and labels.

   According to the Renewable Fuels Association, as of November 2006; 107
   grain ethanol biorefineries in the United States have the capacity to
   produce 5.1 billion gallons of ethanol. An additional 56 construction
   projects underway (in the U.S.) can add 3.8 billion gallons of new
   capacity in the next 18 months. Over time, it is beleived that a
   material portion of the ~150 billion gallon per year market for
   gasoline will begin to be replaced with fuel ethanol. Growth in fuel
   ethanol in the United States is largely being driven by financial
   incentives that naturally exist when oil prices are over a certain
   level, as ethanol typically costs under $1.50 per gallon to manufacture
   (of course this is sensitive to corn prices) and is exempt from the
   $0.52 per gallon federal gasoline tax. However, the United States RFS
   (renewable fuel standard) requires that 4 billion gallons of "renewable
   fuel" be used in 2006 and this requirement will grow to 7.5 billion
   gallons per annum by 2012. .

Alcoholic beverages

   Alcoholic beverages vary considerably in their ethanol content and in
   the foodstuffs from which they are produced. Most alcoholic beverages
   can be broadly classified as fermented beverages, beverages made by the
   action of yeast on sugary foodstuffs, or as distilled beverages,
   beverages whose preparation involves concentrating the ethanol in
   fermented beverages by distillation. The ethanol content of a beverage
   is usually measured in terms of the volume fraction of ethanol in the
   beverage, expressed either as a percentage or in alcoholic proof units.

   Fermented beverages can be broadly classified by the foodstuff from
   which they are fermented. Beers are made from cereal grains or other
   starchy materials, wines and ciders from fruit juices, and meads from
   honey. Cultures around the world have made fermented beverages from
   numerous other foodstuffs, and local and national names for various
   fermented beverages abound. Fermented beverages may contain up to
   15–20% ethanol by volume, the upper limit being set by the yeast's
   tolerance for ethanol, or by the amount of sugar in the starting
   material.

   Distilled beverages are made by distilling fermented beverages. Broad
   categories of distilled beverages include whiskies, distilled from
   fermented cereal grains; brandies, distilled from fermented fruit
   juices, and rum, distilled from fermented molasses or sugarcane juice.
   Vodka and similar neutral grain spirits can be distilled from any
   fermented material (grain or potatoes is most common); these spirits
   are so thoroughly distilled that no tastes from the particular starting
   material remain. Numerous other spirits and liqueurs are prepared by
   infusing flavours from fruits, herbs, and spices into distilled
   spirits. A traditional example is gin, the infusion of juniper berries
   into neutral grain alcohol.

   In a few beverages, ethanol is concentrated by means other than
   distillation. Applejack is traditionally made by freeze distillation:
   water is frozen out of fermented apple cider, leaving a more
   ethanol-rich liquid behind. Fortified wines are prepared by adding
   brandy or some other distilled spirit to partially-fermented wine. This
   kills the yeast and conserves some of the sugar in grape juice; such
   beverages are not only more ethanol-rich, but also sweeter than other
   wines.

Chemicals derived from ethanol

   Ethyl esters

   In the presence of an acid catalyst (typically sulfuric acid) ethanol
   reacts with carboxylic acids to produce ethyl esters:

          CH[3]CH[2]OH + RCOOH → RCOOCH[2]CH[3] + H[2]O

   The two largest-volume ethyl esters are ethyl acrylate (from ethanol
   and acrylic acid) and ethyl acetate (from ethanol and acetic acid).
   Ethyl acrylate is a monomer used to prepare acrylate polymers for use
   in coatings and adhesives. Ethyl acetate is a common solvent used in
   paints, coatings, and in the pharmaceutical industry; its most familiar
   application in the household is as a solvent for nail polish. A variety
   of other ethyl esters are used in much smaller volumes as artificial
   fruit flavorings.

   Vinegar

   Vinegar is a dilute solution of acetic acid prepared by the action of
   Acetobacter bacteria on ethanol solutions. Although traditionally
   prepared from alcoholic beverages including wine, apple cider, and
   unhopped beer, vinegar can also be made from solutions of industrial
   ethanol. Vinegar made from distilled ethanol is called "distilled
   vinegar", and is commonly used in food pickling and as a condiment.

   Ethylamines

   When heated to 150–220 °C over a silica- or alumina-supported nickel
   catalyst, ethanol and ammonia react to produce ethylamine. Further
   reaction leads to diethylamine and triethylamine:

          CH[3]CH[2]OH + NH[3] → CH[3]CH[2]NH[2] + H[2]O
          CH[3]CH[2]OH + CH[3]CH[2]NH[2] → (CH[3]CH[2])[2]NH + H[2]O
          CH[3]CH[2]OH + (CH[3]CH[2])[2]NH → (CH[3]CH[2])[3]N + H[2]O

   The ethylamines find use in the synthesis of pharmaceuticals,
   agricultural chemicals, and surfactants.

   Other chemicals

   Ethanol in the past has been used commercially to synthesize dozens of
   other high-volume chemical commodities. At the present, it has been
   supplanted in many applications by less costly petrochemical
   feedstocks. However, in markets with abundant agricultural products,
   but a less developed petrochemical infrastructure, such as the People's
   Republic of China, Pakistan, India, and Brazil, ethanol can be used to
   produce chemicals that would be produced from petroleum in the West,
   including ethylene and butadiene.

Other uses

   Ethanol is easily soluble in water in all proportions with a slight
   overall decrease in volume when the two are mixed. Absolute ethanol and
   95% ethanol are themselves good solvents, somewhat less polar than
   water and used in perfumes, paints and tinctures. Other proportions of
   ethanol with water or other solvents can also be used as a solvent.
   Alcoholic drinks have a large variety of tastes because various flavor
   compounds are dissolved during brewing. When ethanol is produced as a
   mixing beverage it is a neutral grain spirit.

   Ethanol is used in medical wipes and in most common antibacterial hand
   sanitizer gels at a concentration of about 62% ( percentage by weight,
   not volume) as an antiseptic. The peak of the disinfecting power occurs
   around 70% ethanol; stronger and weaker solutions of ethanol have a
   lessened ability to disinfect. Solutions of this strength are often
   used in laboratories for disinfecting work surfaces. Ethanol kills
   organisms by denaturing their proteins and dissolving their lipids and
   is effective against most bacteria and fungi, and many viruses, but is
   ineffective against bacterial spores. Alcohol does not act like an
   antibiotic and is not effective against infections by ingestion.
   Ethanol in the low concentrations typically found in most alcoholic
   beverages does not have useful disinfectant or antiseptic properties,
   internally or externally.

   Wine with less than 16% ethanol cannot protect itself against bacteria.
   Because of this, port is often fortified with ethanol to at least 18%
   ethanol by volume to halt fermentation for retaining sweetness and in
   preparation for aging, at which point it becomes possible to prevent
   the invasion of bacteria into the port, and to store the port for long
   periods of time in wooden containers that can 'breathe', thereby
   permitting the port to age safely without spoiling. Because of
   ethanol's disinfectant property, alcoholic beverages of 18% ethanol or
   more by volume can be safely stored for a very long time.

Metabolism and toxicology

   Pure ethanol is a tasteless liquid with a strong and distinctive odour
   that produces a characteristic heat-like sensation when brought into
   contact with the tongue or mucous membranes. When applied to open
   wounds (as for disinfection) it produces a strong stinging sensation.
   Pure or highly concentrated ethanol may permanently damage living
   tissue on contact. Ethanol applied to unbroken skin cools the skin
   rapidly through evaporation.

   In the human body, ethanol is first oxidized to acetaldehyde, and then
   to acetic acid. The first step is catalysed by the enzyme alcohol
   dehydrogenase, and the second by acetaldehyde dehydrogenase. Some
   individuals have less effective forms of one or both of these enzymes,
   and can experience more severe symptoms from ethanol consumption than
   others. Conversely, those who have acquired ethanol tolerance have a
   greater quantity of these enzymes, and metabolize ethanol more rapidly.

   BAC (mg/dL)                                                      Symptoms
            50                           Euphoria, talkativeness, relaxation
           100 Central nervous system depression, impaired motor and sensory
                                                function, impaired cognition
          >140                                 Decreased blood flow to brain
           300                        Stupefaction, possible unconsciousness
           400                                                Possible death
          >550                                           Death highly likely

   The amount of ethanol in the body is typically quanitified by blood
   alcohol content (BAC), the milligrams of ethanol per 100 milliliters of
   blood. The table at right summarizes the symptoms of ethanol
   consumption. Small doses of ethanol generally produce euphoria and
   relaxation; people experiencing these symptoms tend to become talkative
   and less inhibited, and may exhibit poor judgment. At higher dosages
   (BAC > 0.10), ethanol acts as a central nervous system depressant,
   producing at progressively higher dosages, impaired sensory and motor
   function, slowed cognition, stupefaction, unconsciousness, and possible
   death.

   The initial product of ethanol metabolism, acetaldehyde, is more toxic
   than ethanol itself. The body can quickly detoxify some acetaldehyde by
   reaction with glutathione and similar thiol-containing biomolecules.
   When acetaldehyde is produced beyond the capacity of the body's
   glutathione supply to detoxify it, it accumulates in the bloodstream
   until further oxidized to acetic acid. The headache, nausea, and
   malaise associated with an alcohol hangover stem from a combination of
   dehydration and acetaldehyde poisoning; many health conditions
   associated with chronic ethanol abuse, including liver cirrhosis,
   alcoholism, and some forms of cancer, have been linked to acetaldehyde.
   The judicial system in the United States, in a number of jurisdictions,
   promoted the use of disulfiram, known as Antabuse, for persons
   convicted of driving while (alcohol) intoxicated. Disulfuram interferes
   with hepatic acetaldehyde metabolism, exacerbating the discomforts
   noted above. Numerous deaths, said to be related to disulfuram use, led
   to the elimination of these court-based programs. Some medications,
   including paracetamol ( acetaminophen), as well as exposure to
   organochlorides, can deplete the body's glutathione supply, enhancing
   both the acute and long-term risks of even moderate ethanol
   consumption. Frequent use of alcoholic beverages has also been shown to
   be a major contributing factor in cases of elevated blood levels of
   triglycerides.

   Ethanol has been shown to increase the growth of Acinetobacter
   baumannii, a bacterium responsible for pneumonia, meningitis and
   urinary tract infections. This finding may contradict the common
   misconception that drinking alcohol could kill off a budding infection.
   (Smith and Snyder, 2005)

Hazards

     * Ethanol-water solutions greater than about 50% ethanol by volume
       are flammable and easily ignited. Ethanol-water solutions below 50%
       ethanol by volume may also be flammable if the solution is
       vaporized by heating (as in some cooking methods that call for wine
       to be added to a hot pan, causing it to flash boil into a vapor,
       which is then ignited to "burn off" excessive alcohol).

   Retrieved from " http://en.wikipedia.org/wiki/Ethanol"
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   with only minor checks and changes (see www.wikipedia.org for details
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