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Ethanol (abbr. EtOH; also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an
organic compound In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon chemical bond, bonds. Due to carbon's ability to Catenation, catenate (form chains with other carbon atoms), millions of organic c ...
. It is an alcohol with the chemical formula . Its formula can be also written as or (an
ethyl group
ethyl group
linked to a
hydroxyl group
hydroxyl group
). Ethanol is a volatile, flammable, colorless liquid with a characteristic wine-like odor and pungent taste. It is a psychoactive recreational drug, the active ingredient in alcoholic drinks. Ethanol is naturally produced by the fermentation process of sugars by
yeast
yeast
s or via petrochemical processes such as
ethylene
ethylene
hydration. It has medical applications as an
antiseptic
antiseptic
and disinfectant. It is used as a chemical
solvent A solvent (s) (from the Latin language, Latin ''wikt:solvo#Latin, solvō'', "loosen, untie, solve") is a substance that dissolves a solute, resulting in a Solution (chemistry), solution. A solvent is usually a liquid but can also be a solid, a ...

solvent
and in the synthesis of
organic compound In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon chemical bond, bonds. Due to carbon's ability to Catenation, catenate (form chains with other carbon atoms), millions of organic c ...
s, and as a fuel source. Ethanol also can be dehydrated to make ethylene, an important chemical feedstock. As of 2006, world production of ethanol was , coming mostly from Brazil and the U.S.


Etymology

''Ethanol'' is the systematic name defined by the
International Union of Pure and Applied Chemistry The International Union of Pure and Applied Chemistry (IUPAC ) is an international federation of National Adhering Organizations working for the advancement of the chemical sciences, especially by developing nomenclature and terminology. It is ...
for a compound consisting of an alkyl group with two carbon
atom Every atom is composed of a atomic nucleus, nucleus and one or more electrons bound to the nucleus. The nucleus is made of one or more protons and a number of neutrons. Only the most common variety of hydrogen has no neutrons. Every solid, l ...

atom
s (prefix "eth-"), having a single bond between them (infix "-an-") and an attached functional group −OH group (suffix "-ol"). The "eth-" prefix and the qualifier "ethyl" in "ethyl alcohol" originally come from the name "ethyl" assigned in 1834 to the group − by
Justus Liebig
Justus Liebig
. He coined the word from the
German
German
name ''Aether'' of the compound −O− (commonly called "ether" in
English
English
, more specifically called " diethyl ether"). According to the ''
Oxford English Dictionary The ''Oxford English Dictionary'' (''OED'') is the first and foundational historical dictionary of the English language, published by Oxford University Press (OUP). It traces the historical development of the English language, providing a com ...
'', ''Ethyl'' is a contraction of the Ancient Greek αἰθήρ (', "upper air") and the Greek word ὕλη (', "substance"). The name ''ethanol'' was coined as a result of a resolution on naming alcohols and phenols that was adopted at the International Conference on Chemical Nomenclature that was held in April 1892 in Geneva, Switzerland. The term ''alcohol'' now refers to a wider class of substances in chemistry nomenclature, but in common parlance it remains the name of ethanol. It is a medieval loan from
Arabic
Arabic
'' al-kuḥl'', a powdered ore of antimony used since antiquity as a cosmetic, and retained that meaning in Middle Latin. The use of 'alcohol' for ethanol (in full, "alcohol of wine") is modern and was first recorded in 1753. Before the late 18th century the term "alcohol" generally referred to any sublimated substance.


Uses


Medical


Antiseptic

Ethanol is used in medical wipes and most commonly in antibacterial hand sanitizer gels as an
antiseptic
antiseptic
for its bactericidal and anti-fungal effects. Ethanol kills microorganisms by dissolving their membrane lipid bilayer and denaturing their
protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metabo ...

protein
s, and is effective against most
bacteria
bacteria
,
fungi
fungi
and
virus A virus is a wikt:submicroscopic, submicroscopic infectious agent that replicates only inside the living Cell (biology), cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and ...

virus
es. However, it is ineffective against bacterial spores, but that can be alleviated by using
hydrogen peroxide Hydrogen peroxide is a chemical compound with the formula . In its pure form, it is a very pale blue liquid that is slightly more viscosity, viscous than Properties of water, water. It is used as an oxidizer, bleaching agent, and antiseptic, usua ...

hydrogen peroxide
. A solution of 70% ethanol is more effective than pure ethanol because ethanol relies on water molecules for optimal antimicrobial activity. Absolute ethanol may inactivate microbes without destroying them because the alcohol is unable to fully permeate the microbe's membrane. Ethanol can also be used as a disinfectant and antiseptic because it causes cell dehydration by disrupting the osmotic balance across the cell membrane, so water leaves the cell leading to cell death.


Antidote

Ethanol may be administered as an
antidote
antidote
to ethylene glycol poisoning and methanol poisoning. Ethanol serves this process by acting as a competitive inhibitor against
methanol
methanol
and
ethylene glycol
ethylene glycol
for
alcohol dehydrogenase
alcohol dehydrogenase
. Though it has more side effects, ethanol is less expensive and more readily available than
fomepizole
fomepizole
, which is also used as an antidote for methanol and ethylene glycol poisoning.


Medicinal solvent

Ethanol, often in high concentrations, is used to dissolve many water-insoluble medications and related compounds. Liquid preparations of pain medications, cough and cold medicines, and mouth washes, for example, may contain up to 25% ethanol and may need to be avoided in individuals with adverse reactions to ethanol such as alcohol-induced respiratory reactions. Ethanol is present mainly as an antimicrobial preservative in over 700 liquid preparations of medicine including
acetaminophen
acetaminophen
, iron supplements,
ranitidine
ranitidine
,
furosemide Furosemide is a loop diuretic medication used to treat edema, fluid build-up due to heart failure, hepatic cirrhosis, liver scarring, or kidney disease. It may also be used for the treatment of hypertension, high blood pressure. It can be take ...
, mannitol,
phenobarbital Phenobarbital, also known as phenobarbitone or phenobarb, sold under the brand name Luminal among others, is a medication of the barbiturate type. It is recommended by the World Health Organization (WHO) for the treatment of certain types of ep ...
, trimethoprim/sulfamethoxazole and over-the-counter cough medicine.


Pharmacology

In mammals, ethanol is primarily metabolized in the liver and stomach by
alcohol dehydrogenase
alcohol dehydrogenase
(ADH) enzymes. These enzymes catalyze the
oxidation Redox (reduction–oxidation, , ) is a type of chemical reaction in which the oxidation states of substrate (chemistry), substrate change. Oxidation is the loss of Electron, electrons or an increase in the oxidation state, while reduction ...
of ethanol into
acetaldehyde Acetaldehyde (IUPAC systematic name ethanal) is an organic chemical compound with the formula In science, a formula is a concise way of expressing information symbolically, as in a mathematical formula or a ''chemical formula''. The informa ...
(ethanal): :CH3CH2OH + NAD+ → CH3CHO + NADH + H+ When present in significant concentrations, this metabolism of ethanol is additionally aided by the
cytochrome P450 Cytochromes P450 (CYPs) are a Protein superfamily, superfamily of enzymes containing heme as a cofactor (biochemistry), cofactor that functions as monooxygenases. In mammals, these proteins oxidize steroids, fatty acids, and xenobiotics, and are ...
enzyme CYP2E1 in humans, while trace amounts are also metabolized by catalase. The resulting intermediate, acetaldehyde, is a known carcinogen, and poses significantly greater toxicity in humans than ethanol itself. Many of the symptoms typically associated with alcohol intoxication—as well as many of the health hazards typically associated with the long-term consumption of ethanol—can be attributed to acetaldehyde toxicity in humans. The subsequent oxidation of acetaldehyde into acetate is performed by aldehyde dehydrogenase (ALDH) enzymes. A mutation in the ALDH2 gene that encodes for an inactive or dysfunctional form of this enzyme affects roughly 50% of east Asian populations, contributing to the characteristic alcohol flush reaction that can cause temporary reddening of the skin as well as a number of related, and often unpleasant, symptoms of acetaldehyde toxicity. This mutation is typically accompanied by another mutation in the
alcohol dehydrogenase
alcohol dehydrogenase
enzyme ADH1B in roughly 80% of east Asians, which improves the catalytic efficiency of converting ethanol into acetaldehyde.


Recreational

As a
central nervous system The central nervous system (CNS) is the part of the nervous system consisting primarily of the brain and spinal cord. The CNS is so named because the brain integrates the received information and coordinates and influences the activity of all par ...
depressant, ethanol is one of the most commonly consumed psychoactive drugs. Despite alcohol's psychoactive and carcinogenic properties, it is readily available and legal for sale in most countries. However, there are laws regulating the sale, exportation/importation, taxation, manufacturing, consumption, and possession of alcoholic beverages. The most common regulation is prohibition for minors.


Fuel


Engine fuel

The largest single use of ethanol is as an engine
fuel A fuel is any material that can be made to react with other substances so that it releases energy as thermal energy or to be used for work (physics), work. The concept was originally applied solely to those materials capable of releasing chem ...
and fuel additive.
Brazil Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, ...
in particular relies heavily upon the use of ethanol as an engine fuel, due in part to its role as one of the world's leading producers of ethanol.
Gasoline Gasoline (; ) or petrol (; ) (see ) is a transparent, petroleum-derived flammable liquid that is used primarily as a fuel in most Spark-ignition engine, spark-ignited internal combustion engines (also known as petrol engines). It consists ...
sold in Brazil contains at least 25%
anhydrous A substance is anhydrous if it contains no water. Many processes in chemistry can be impeded by the presence of water; therefore, it is important that water-free reagents and techniques are used. In practice, however, it is very difficult to achie ...
ethanol. Hydrous ethanol (about 95% ethanol and 5% water) can be used as fuel in more than 90% of new gasoline-fueled cars sold in the country. The US and many other countries primarily use E10 (10% ethanol, sometimes known as gasohol) and E85 (85% ethanol) ethanol/gasoline mixtures. Over time, it is believed that a material portion of the ≈ per year market for gasoline will begin to be replaced with fuel ethanol. Australian law limits the use of pure ethanol from sugarcane waste to 10% in automobiles. Older cars (and vintage cars designed to use a slower burning fuel) should have the engine valves upgraded or replaced. According to an industry advocacy group, ethanol as a fuel reduces harmful tailpipe emissions of carbon monoxide, particulate matter, oxides of nitrogen, and other ozone-forming pollutants. Argonne National Laboratory analyzed greenhouse gas emissions of many different engine and fuel combinations, and found that biodiesel/petrodiesel blend ( B20) showed a reduction of 8%, conventional E85 ethanol blend a reduction of 17% and cellulosic ethanol 64%, compared with pure gasoline. Ethanol has a much greater research octane number (RON) than gasoline, meaning it is less prone to pre-ignition, allowing for better ignition advance which means more torque, and efficiency in addition to the lower carbon emissions. Ethanol
combustion Combustion, or burning, is a high-temperature exothermic redox chemical reaction between a fuel (the reductant) and an oxidant, usually atmospheric oxygen, that produces oxidized, often gaseous products, in a mixture termed as smoke. Combusti ...
in an
internal combustion engine An internal combustion engine (ICE or IC engine) is a heat engine in which the combustion of a fuel occurs with an oxidizer (usually air) in a combustion chamber that is an integral part of the working fluid flow circuit. In an internal combust ...
yields many of the products of incomplete combustion produced by gasoline and significantly larger amounts of
formaldehyde Formaldehyde ( , ) (Preferred IUPAC name, systematic name methanal) is a naturally occurring organic compound with the chemical formula, formula and structure . The pure compound is a pungent, colourless gas that Polymerization, polymerises s ...
and related species such as acetaldehyde. This leads to a significantly larger photochemical reactivity and more ground level ozone. This data has been assembled into The Clean Fuels Report comparison of fuel emissions and show that ethanol exhaust generates 2.14 times as much ozone as gasoline exhaust. When this is added into the custom ''Localized Pollution Index (LPI)'' of The Clean Fuels Report, the local pollution of ethanol (pollution that contributes to smog) is rated 1.7, where gasoline is 1.0 and higher numbers signify greater pollution. The California Air Resources Board formalized this issue in 2008 by recognizing control standards for formaldehydes as an emissions control group, much like the conventional NOx and Reactive Organic Gases (ROGs). More than 20% of Brazilian cars are able to use 100% ethanol as fuel, which includes ethanol-only engines and flex-fuel engines. Flex-fuel engines in Brazil are able to work with all ethanol, all gasoline or any mixture of both. In the U.S. flex-fuel vehicles can run on 0% to 85% ethanol (15% gasoline) since higher ethanol blends are not yet allowed or efficient. Brazil supports this fleet of ethanol-burning automobiles with large national infrastructure that produces ethanol from domestically grown sugarcane. Ethanol's high miscibility with water makes it unsuitable for shipping through modern pipelines like liquid hydrocarbons. Mechanics have seen increased cases of damage to small engines (in particular, the carburetor) and attribute the damage to the increased water retention by ethanol in fuel.


Rocket fuel

Ethanol was commonly used as fuel in early bipropellant rocket (liquid-propelled) vehicles, in conjunction with an
oxidizer An oxidizing agent (also known as an oxidant, oxidizer, electron recipient, or electron acceptor) is a substance in a redox chemical reaction that gains or "Electron acceptor, accepts"/"receives" an electron from a (called the , , or ). In ot ...
such as liquid oxygen. The German A-4 ballistic rocket of World War II (better known by its propaganda name ), which is credited as having begun the space age, used ethanol as the main constituent of ''B-Stoff''. Under such nomenclature, the ethanol was mixed with 25% water to reduce the combustion chamber temperature.Braeunig, Robert A
"Rocket Propellants"
''Rocket & Space Technology'', 2006. Retrieved 23 August 2007.
The design team helped develop U.S. rockets following World War II, including the ethanol-fueled Redstone rocket which launched the first U.S. satellite. Alcohols fell into general disuse as more energy-dense rocket fuels were developed, although ethanol is currently used in lightweight rocket-powered racing aircraft.


Fuel cells

Commercial fuel cells operate on reformed natural gas,
hydrogen Hydrogen is the chemical element with the Symbol (chemistry), symbol H and atomic number 1. Hydrogen is the lightest element. At standard temperature and pressure, standard conditions hydrogen is a gas of diatomic molecules having the chemical ...
or methanol. Ethanol is an attractive alternative due to its wide availability, low cost, high purity and low toxicity. There is a wide range of fuel cell concepts that have entered trials including direct-ethanol fuel cells, auto-thermal reforming systems and thermally integrated systems. The majority of work is being conducted at a research level although there are a number of organizations at the beginning of the commercialization of ethanol fuel cells.


Household heating and cooking

Ethanol fireplaces can be used for home heating or for decoration. Ethanol can also be used as stove fuel for cooking.


Feedstock

Ethanol is an important industrial ingredient. It has widespread use as a precursor for other organic compounds such as ethyl halides, ethyl
ester In chemistry, an ester is a chemical compound, compound derived from an oxoacid (organic or inorganic) in which at least one hydroxyl group () is replaced by an alkoxy group (), as in the substitution reaction of a carboxylic acid and an Alcohol ...
s, diethyl ether, acetic acid, and ethyl
amine In chemistry, amines (, ) are chemical compound, compounds and functional groups that contain a base (chemistry), basic nitrogen atom with a lone pair. Amines are formally derivative (chemistry), derivatives of ammonia (), wherein one or mo ...
s.


Solvent

Ethanol is considered a universal
solvent A solvent (s) (from the Latin language, Latin ''wikt:solvo#Latin, solvō'', "loosen, untie, solve") is a substance that dissolves a solute, resulting in a Solution (chemistry), solution. A solvent is usually a liquid but can also be a solid, a ...

solvent
, as its molecular structure allows for the dissolving of both polar,
hydrophilic A hydrophile is a molecule or other molecular entity that is intermolecular force, attracted to water molecules and tends to be dissolution (chemistry), dissolved by water.Liddell, H.G. & Scott, R. (1940). ''A Greek-English Lexicon'' Oxford: Clar ...
and nonpolar, hydrophobic compounds. As ethanol also has a low
boiling point The boiling point of a substance is the temperature at which the vapor pressure of a liquid equals the pressure surrounding the liquid and the liquid changes into a vapor. The boiling point of a liquid varies depending upon the surrounding en ...
, it is easy to remove from a solution that has been used to dissolve other compounds, making it a popular extracting agent for botanical oils. Cannabis oil extraction methods often use ethanol as an extraction solvent, and also as a post-processing solvent to remove oils, waxes, and
chlorophyll Chlorophyll (also chlorophyl) is any of several related green pigments found in cyanobacteria and in the chloroplasts of algae and plants. Its name is derived from the Ancient Greek, Greek words , ("pale green") and , ("leaf"). Chlorophyll al ...
from solution in a process known as winterization. Ethanol is found in paints, tinctures, markers, and personal care products such as mouthwashes, perfumes and deodorants. However, polysaccharides precipitate from aqueous solution in the presence of alcohol, and ethanol precipitation is used for this reason in the purification of DNA and RNA.


Low-temperature liquid

Because of its low freezing point of and low toxicity, ethanol is sometimes used in laboratories (with
dry ice Dry ice is the solid form of carbon dioxide. It is commonly used for temporary refrigeration as CO2 does not have a liquid state at normal atmospheric pressure and Sublimation (phase transition), sublimates directly from the solid state to the ga ...
or other coolants) as a cooling bath to keep vessels at temperatures below the freezing point of water. For the same reason, it is also used as the active fluid in alcohol thermometers.


Chemistry


Chemical formula

Ethanol is a 2-carbon alcohol. Its molecular formula is CH3CH2OH. An alternative notation is CH3−CH2−OH, which indicates that the carbon of a
methyl group In organic chemistry, a methyl group is an alkyl derived from methane, containing one carbon atom chemical bond, bonded to three hydrogen atoms, having chemical formula . In chemical formula, formulas, the group is often skeletal formula#Pseudoe ...
(CH3−) is attached to the carbon of a
methylene group In organic chemistry, a methylene group is any part of a molecule that consists of two hydrogen atoms chemical bond, bound to a carbon atom, which is connected to the remainder of the molecule by two single bond, single bonds. The group may be re ...
(−CH2–), which is attached to the oxygen of a (−OH). It is a constitutional
isomer In chemistry, isomers are molecules or polyatomic ions with identical molecular formulae – that is, same number of atoms of each element (chemistry), element – but distinct arrangements of atoms in space. Isomerism is existence or possibil ...
of dimethyl ether. Ethanol is sometimes abbreviated as EtOH, using the common organic chemistry notation of representing the ethyl group (C2H5−) with Et.


Physical properties

Ethanol is a volatile, colorless liquid that has a slight odor. It burns with a smokeless blue flame that is not always visible in normal light. The physical properties of ethanol stem primarily from the presence of its hydroxyl group and the shortness of its carbon chain. Ethanol's hydroxyl group is able to participate in hydrogen bonding, rendering it more viscous and less volatile than less polar organic compounds of similar molecular weight, such as propane. Ethanol's adiabatic flame temperature for combustion in air is 2082 Celsius or 3779 Fahrenheit. Ethanol is slightly more refractive than water, having a refractive index of 1.36242 (at λ=589.3 nm and ). The triple point for ethanol is at a pressure of .


Solvent properties

Ethanol is a versatile solvent, miscible with water and with many organic solvents, including
acetic acid Acetic acid , systematically named ethanoic acid , is an acidic, colourless liquid and organic compound In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon chemical bond, bond ...
,
acetone Acetone (2-propanone or dimethyl ketone), is an organic compound with the chemical formula, formula . It is the simplest and smallest ketone (). It is a colorless, highly Volatile organic compound, volatile and flammable liquid with a character ...
, benzene, carbon tetrachloride, chloroform, diethyl ether, ethylene glycol,
glycerol Glycerol (), also called glycerine in British English and glycerin in American English, is a simple triol compound. It is a colorless, odorless, viscous liquid that is sweet-tasting and non-toxic. The glycerol backbone is found in lipids known ...
, nitromethane,
pyridine Pyridine is a basic (chemistry), basic heterocyclic compound, heterocyclic organic compound with the chemical formula . It is structurally related to benzene, with one methine group replaced by a nitrogen atom. It is a highly flammable, weakl ...
, and toluene. Its main use as a solvent is in making tincture of iodine, cough syrups etc. It is also miscible with light aliphatic hydrocarbons, such as pentane and hexane, and with aliphatic chlorides such as trichloroethane and tetrachloroethylene. Ethanol's miscibility with water contrasts with the immiscibility of longer-chain alcohols (five or more carbon atoms), whose water miscibility decreases sharply as the number of carbons increases. The miscibility of ethanol with alkanes is limited to alkanes up to undecane: mixtures with dodecane and higher alkanes show a miscibility gap below a certain temperature (about 13 °C for dodecane). The miscibility gap tends to get wider with higher alkanes, and the temperature for complete miscibility increases. Ethanol-water mixtures have less volume than the sum of their individual components at the given fractions. Mixing equal volumes of ethanol and water results in only 1.92 volumes of mixture. Mixing ethanol and water is exothermic, with up to 777 J/mol being released at 298 K. Mixtures of ethanol and water form an azeotrope at about 89 mole-% ethanol and 11 mole-% water or a mixture of 95.6 percent ethanol by mass (or about 97%
alcohol by volume Alcohol by volume (abbreviated as ABV, abv, or alc/vol) is a standard measure of how much alcohol (ethanol) is contained in a given volume of an alcoholic beverage (expressed as a volume percent). It is defined as the number of millilitres (mL) o ...
) at normal pressure, which boils at 351K (78 °C). This azeotropic composition is strongly temperature- and pressure-dependent and vanishes at temperatures below 303 K. Hydrogen bonding causes pure ethanol to be
hygroscopic Hygroscopy is the phenomenon of attracting and holding water molecules via either absorption or adsorption from the surrounding environment, which is usually at normal or room temperature. If water molecules become suspended among the substance ...
to the extent that it readily absorbs water from the air. The polar nature of the hydroxyl group causes ethanol to dissolve many ionic compounds, notably
sodium Sodium is a chemical element with the Symbol (chemistry), symbol Na (from Latin ''natrium'') and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is an alkali metal, being in group 1 element, group 1 of the ...
and
potassium hydroxide Potassium hydroxide is an inorganic compound with the formula K OH, and is commonly called caustic potash. Along with sodium hydroxide (NaOH), KOH is a prototypical strong base. It has many industrial and niche applications, most of which exp ...
s,
magnesium chloride Magnesium chloride is the family of inorganic compounds with the chemical formula, formula , where x can range from 0 to 12. These salts are colorless or white solids that are highly soluble in water. These compounds and their solutions, both of w ...
,
calcium chloride Calcium chloride is an inorganic compound, a salt (chemistry), salt with the chemical formula . It is a white crystalline solid at room temperature, and it is highly solubility, soluble in water. It can be created by neutralising hydrochloric aci ...
,
ammonium chloride Ammonium chloride is an inorganic compound with the formula NH4Cl and a white crystalline salt that is highly soluble in water. Solutions of ammonium chloride are mildly acidic. In its naturally occurring mineralogic form, it is known as sa ...
, ammonium bromide, and sodium bromide.
Sodium Sodium is a chemical element with the Symbol (chemistry), symbol Na (from Latin ''natrium'') and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is an alkali metal, being in group 1 element, group 1 of the ...
and potassium chlorides are slightly soluble in ethanol. Because the ethanol molecule also has a nonpolar end, it will also dissolve nonpolar substances, including most
essential oil An essential oil is a concentrated hydrophobic liquid containing Volatility (chemistry), volatile (easily evaporated at normal temperatures) chemical compounds from plants. Essential oils are also known as volatile oils, ethereal oils, aetherol ...
s''Merck Index of Chemicals and Drugs'', 9th ed.; monographs 6575 through 6669 and numerous flavoring, coloring, and medicinal agents. 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 in a glass, ethanol evaporates quickly from the thin film of wine on the wall of the glass. As the wine's 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.


Flammability

An ethanol–water solution will catch fire if heated above a temperature called its flash point and an ignition source is then applied to it. For 20% alcohol by mass (about 25% by volume), this will occur at about . The flash point of pure ethanol is , but may be influenced very slightly by atmospheric composition such as pressure and humidity. Ethanol mixtures can ignite below average room temperature. Ethanol is considered a flammable liquid (Class 3 Hazardous Material) in concentrations above 2.35% by mass (3.0% by volume; 6 proof). Dishes using burning alcohol for culinary effects are called flambé.


Natural occurrence

Ethanol is a byproduct of the metabolic process of yeast. As such, ethanol will be present in any yeast habitat. Ethanol can commonly be found in overripe fruit. Ethanol produced by symbiotic yeast can be found in bertam palm blossoms. Although some animal species, such as the pentailed treeshrew, exhibit ethanol-seeking behaviors, most show no interest or avoidance of food sources containing ethanol. Ethanol is also produced during the germination of many plants as a result of natural anaerobiosis. Ethanol has been detected in
outer space Outer space, commonly shortened to space, is the expanse that exists beyond Earth and Earth atmosphere, its atmosphere and between astronomical object, celestial bodies. Outer space is not completely empty—it is a Ultra-high vacuum, near-per ...
, forming an icy coating around dust grains in interstellar clouds. Minute quantity amounts (average 196 ppb) of endogenous ethanol and acetaldehyde were found in the exhaled breath of healthy volunteers. Auto-brewery syndrome, also known as gut fermentation syndrome, is a rare medical condition in which intoxicating quantities of ethanol are produced through endogenous fermentation within the digestive system.


Production

Ethanol is produced both as a
petrochemical Petrochemicals (sometimes abbreviated as petchems) are the product (chemistry), chemical products obtained from petroleum by refining. Some chemical compounds made from petroleum are also obtained from other fossil fuels, such as coal or natural ...
, through the hydration of and, via biological processes, by fermenting sugars with . Which process is more economical depends on prevailing prices of
petroleum Petroleum, also known as crude oil, or simply oil, is a naturally occurring yellowish-black liquid mixture of mainly hydrocarbons, and is found in geological formations. The name ''petroleum'' covers both naturally occurring unprocessed crude ...
and grain feed stocks.


Sources

World production of ethanol in 2006 was , with 69% of the world supply coming from Brazil and the U.S. Brazilian ethanol is produced from
sugarcane Sugarcane or sugar cane is a species of (often hybrid) tall, Perennial plant, perennial grass (in the genus ''Saccharum'', tribe Andropogoneae) that is used for sugar Sugar industry, production. The plants are 2–6 m (6–20 ft) tall with ...
, which has relatively high yields (830% more fuel than the fossil fuels used to produce it) compared to some other energy crops. Sugarcane not only has a greater concentration of sucrose than corn (by about 30%), but is also much easier to extract. The bagasse generated by the process is not discarded, but burned by power plants to produce electricity. Bagasse burning accounts for around 9% of the electricity produced in Brazil. In the 1970s most industrial ethanol in the U.S. was made as a petrochemical, but in the 1980s the U.S. introduced subsidies for corn-based ethanol. According to the Renewable Fuels Association, as of 30 October 2007, 131 grain ethanol bio-refineries in the U.S. have the capacity to produce of ethanol per year. An additional 72 construction projects underway (in the U.S.) can add of new capacity in the next 18 months. In India ethanol is made from sugarcane. Sweet sorghum is another potential source of ethanol, and is suitable for growing in dryland conditions. The International Crops Research Institute for the Semi-Arid Tropics is investigating the possibility of growing sorghum as a source of fuel, food, and animal feed in arid parts of
Asia Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa Africa is ...
and
Africa Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...
. Sweet sorghum has one-third the water requirement of sugarcane over the same time period. It also requires about 22% less water than corn. The world's first sweet sorghum ethanol distillery began commercial production in 2007 in
Andhra Pradesh Andhra Pradesh (, abbr. AP) is a States and union territories of India, state in the south-eastern Coastal India, coastal region of India. It is the List of states and union territories of India by area, seventh-largest state by area coverin ...
,
India India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the List of countries and dependencies by area, seventh-largest country by area, the List of countries and dependencies by population, second-most populous ...
.


Hydration

Ethanol can be produced from
petrochemical Petrochemicals (sometimes abbreviated as petchems) are the product (chemistry), chemical products obtained from petroleum by refining. Some chemical compounds made from petroleum are also obtained from other fossil fuels, such as coal or natural ...
feed stocks, primarily by the
acid An acid is a molecule or ion capable of either donating a proton (i.e. hydrogen ion, H+), known as a Brønsted–Lowry acid, or forming a covalent bond with an electron pair, known as a Lewis acid A Lewis acid (named for the American p ...
- catalyzed hydration of ethylene. It is often referred to as synthetic ethanol. The catalyst is most commonly
phosphoric acid Phosphoric acid (orthophosphoric acid, monophosphoric acid or phosphoric(V) acid) is a colorless, odorless phosphorus-containing solid, and inorganic compound with the chemical formula . It is commonly encountered as an 85% aqueous solution, w ...
, adsorbed onto a porous support such as silica gel or diatomaceous earth. This catalyst was first used for large-scale ethanol production by the Shell Oil Company in 1947. The reaction is carried out in the presence of high pressure steam at where a 5:3 ethylene to steam ratio is maintained. This process was used on an industrial scale by Union Carbide Corporation and others. It is no longer practiced in the US as fermentation ethanol produced from corn is more economical. In an older process, first practiced on the industrial scale in 1930 by Union Carbide but now almost entirely obsolete, ethylene was hydrated indirectly by reacting it with concentrated
sulfuric acid Sulfuric acid (American spelling and the preferred IUPAC name) or sulphuric acid (English in the Commonwealth of Nations, Commonwealth spelling), known in antiquity as oil of vitriol, is a mineral acid composed of the elements sulfur, oxygen ...
to produce ethyl sulfate, which was hydrolyzed to yield ethanol and regenerate the sulfuric acid:


From carbon dioxide

Ethanol has been produced in the laboratory by converting
carbon dioxide Carbon dioxide ( chemical formula ) is a chemical compound made up of molecules that each have one carbon Carbon () is a chemical element with the chemical symbol, symbol C and atomic number 6. It is nonmetallic and tetravalence, tetraval ...
via biological and electrochemical reactions.


Fermentation

Ethanol in
alcoholic beverage An alcoholic beverage (also called an alcoholic drink, adult beverage, or a drink) is a drink that contains ethanol Ethanol (abbr. EtOH; also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic co ...
s and fuel is produced by fermentation. Certain species of (e.g., '' Saccharomyces cerevisiae'') metabolize sugar, producing ethanol and carbon dioxide. The chemical equations below summarize the conversion: Fermentation is the process of culturing yeast under favorable thermal conditions to produce alcohol. This process is carried out at around . Toxicity of ethanol to yeast limits the ethanol concentration obtainable by brewing; higher concentrations, therefore, are obtained by fortification or
distillation Distillation, or classical distillation, is the process of separation process, separating the components or substances from a liquid mixture by using selective boiling and condensation, usually inside an apparatus known as a still. Dry distilla ...
. The most ethanol-tolerant yeast strains can survive up to approximately 18% ethanol by volume. To produce ethanol from starchy materials such as
cereal A cereal is any Poaceae, grass cultivated for the edible components of its grain (botanically, a type of fruit called a caryopsis), composed of the endosperm, Cereal germ, germ, and bran. Cereal Grain, grain crops are grown in greater quantit ...
s, the
starch Starch or amylum is a polymeric carbohydrate consisting of numerous glucose units joined by glycosidic bonds. This polysaccharide is produced by most green plants for energy storage. Worldwide, it is the most common carbohydrate in human diets, ...
must first be converted into sugars. In brewing
beer Beer is one of the oldest and the most widely consumed type of alcoholic drink in the world, and the third most popular drink overall after water and tea. It is produced by the brewing and Fermentation (food), fermentation of starches, mainl ...
, this has traditionally been accomplished by allowing the grain to germinate, or malt, which produces the
enzyme Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different molecule ...
amylase. When the malted grain is mashed, the amylase converts the remaining starches into sugars.


Cellulose

Sugars for ethanol fermentation can be obtained from
cellulose Cellulose is an organic compound In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon chemical bond, bonds. Due to carbon's ability to Catenation, catenate (form chains with other ...
. Deployment of this technology could turn a number of cellulose-containing agricultural by-products, such as corncobs,
straw Straw is an agricultural byproduct consisting of the dry wikt:stalk, stalks of cereal plants after the grain and chaff have been removed. It makes up about half of the yield of cereal crops such as barley, oats, rice, rye and wheat. It has ...
, and sawdust, into renewable energy resources. Other agricultural residues such as sugarcane bagasse and energy crops such as switchgrass may also be fermentable sugar sources.


Testing

Breweries and
biofuel Biofuel is a fuel that is produced over a short time span from biomass, rather than by the very slow natural processes involved in the formation of fossil fuels, such as oil. According to the United States Energy Information Administration (EIA ...
plants employ two methods for measuring ethanol concentration. Infrared ethanol sensors measure the vibrational frequency of dissolved ethanol using the C−H band at 2900 cm. This method uses a relatively inexpensive solid-state sensor that compares the C−H band with a reference band to calculate the ethanol content. The calculation makes use of the Beer–Lambert law. Alternatively, by measuring the density of the starting material and the density of the product, using a hydrometer, the change in specific gravity during fermentation indicates the alcohol content. This inexpensive and indirect method has a long history in the beer brewing industry.


Purification


Distillation

Ethylene hydration or brewing produces an ethanol–water mixture. For most industrial and fuel uses, the ethanol must be purified.
Fractional distillation Fractional distillation is the separation process, separation of a mixture into its component parts, or fraction (chemistry), fractions. Chemical compounds are separated by heating them to a temperature at which one or more fractions of the mixtur ...
at atmospheric pressure can concentrate ethanol to 95.6% by weight (89.5 mole%). This mixture is an azeotrope with a boiling point of , and ''cannot'' be further purified by distillation. Addition of an entraining agent, such as benzene, cyclohexane, or heptane, allows a new ternary azeotrope comprising the ethanol, water, and the entraining agent to be formed. This lower-boiling ternary azeotrope is removed preferentially, leading to water-free ethanol.


Molecular sieves and desiccants

Apart from distillation, ethanol may be dried by addition of a desiccant, such as molecular sieves,
cellulose Cellulose is an organic compound In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon chemical bond, bonds. Due to carbon's ability to Catenation, catenate (form chains with other ...
, or
cornmeal Cornmeal is a meal (coarse flour) or a cell membrane ground from dried maize, corn. It is a common staple food, and is Mill (grinding), ground to coarse, medium, and fine consistencies, but not as fine as wheat flour can be.Herbst, Sharon, ''Fo ...
. The desiccants can be dried and reused. Molecular sieves can be used to selectively absorb the water from the 95.6% ethanol solution. Molecular sieves of pore-size 3  Ångstrom, a type of zeolite, effectively sequester water molecules while excluding ethanol molecules. Heating the wet sieves drives out the water, allowing regeneration of their dessicant capability.


Membranes and reverse osmosis

Membranes can also be used to separate ethanol and water. Membrane-based separations are not subject to the limitations of the water-ethanol azeotrope because the separations are not based on vapor-liquid equilibria. Membranes are often used in the so-called hybrid membrane distillation process. This process uses a pre-concentration distillation column as the first separating step. The further separation is then accomplished with a membrane operated either in vapor permeation or pervaporation mode. Vapor permeation uses a vapor membrane feed and pervaporation uses a liquid membrane feed.


Other techniques

A variety of other techniques have been discussed, including the following: * Salting using potassium carbonate to exploit its insolubility will cause a phase separation with ethanol and water. This offers a very small potassium carbonate impurity to the alcohol that can be removed by distillation. This method is very useful in purification of ethanol by distillation, as ethanol forms an azeotrope with water. * Direct electrochemical reduction of carbon dioxide to ethanol under ambient conditions using copper nanoparticles on a carbon nanospike film as the catalyst; * Extraction of ethanol from grain mash by supercritical carbon dioxide; * Pervaporation; * Fractional freezing is also used to concentrate fermented alcoholic solutions, such as traditionally made Applejack (beverage); * Pressure swing adsorption.


Grades of ethanol


Denatured alcohol

Pure ethanol and alcoholic beverages are heavily taxed as psychoactive drugs, but ethanol has many uses that do not involve its consumption. To relieve the tax burden on these uses, most jurisdictions waive the tax when an agent has been added to the ethanol to render it unfit to drink. These include bittering agents such as denatonium benzoate and toxins such as methanol, naphtha, and
pyridine Pyridine is a basic (chemistry), basic heterocyclic compound, heterocyclic organic compound with the chemical formula . It is structurally related to benzene, with one methine group replaced by a nitrogen atom. It is a highly flammable, weakl ...
. Products of this kind are called ''denatured alcohol.''


Absolute alcohol

Absolute or anhydrous alcohol refers to ethanol with a low water content. There are various grades with maximum water contents ranging from 1% to a few parts per million (ppm). If azeotropic distillation is used to remove water, it will contain trace amounts of the material separation agent (e.g. benzene). Absolute alcohol is not intended for human consumption. Absolute ethanol is used as a solvent for laboratory and industrial applications, where water will react with other chemicals, and as fuel alcohol. Spectroscopic ethanol is an absolute ethanol with a low absorbance in ultraviolet and visible light, fit for use as a solvent in ultraviolet-visible spectroscopy. Pure ethanol is classed as 200 proof in the US, equivalent to 175 degrees proof in the UK system.


Rectified spirits

Rectified spirit, an azeotropic composition of 96% ethanol containing 4% water, is used instead of anhydrous ethanol for various purposes. Spirits of wine are about 94% ethanol (188 proof). The impurities are different from those in 95% (190 proof) laboratory ethanol.


Reactions

Ethanol is classified as a primary alcohol, meaning that the carbon that its hydroxyl group attaches to has at least two hydrogen atoms attached to it as well. Many ethanol reactions occur at its hydroxyl group.


Ester formation

In the presence of acid catalysts, ethanol reacts with
carboxylic acid In organic chemistry, a carboxylic acid is an organic acid that contains a carboxyl group () attached to an R-group. The general formula of a carboxylic acid is or , with substituent, R referring to the alkyl, alkenyl, aryl, or other group. ...
s to produce ethyl
ester In chemistry, an ester is a chemical compound, compound derived from an oxoacid (organic or inorganic) in which at least one hydroxyl group () is replaced by an alkoxy group (), as in the substitution reaction of a carboxylic acid and an Alcohol ...
s and water: : RCOOH + HOCH2CH3RCOOCH2CH3 + H2O This reaction, which is conducted on large scale industrially, requires the removal of the water from the reaction mixture as it is formed. Esters react in the presence of an acid or base to give back the alcohol and a salt. This reaction is known as saponification because it is used in the preparation of soap. Ethanol can also form esters with inorganic acids. Diethyl sulfate and triethyl phosphate are prepared by treating ethanol with sulfur trioxide and
phosphorus pentoxide Phosphorus pentoxide is a chemical compound with molecular formula Phosphorus, P4Oxygen, O10 (with its common name derived from its empirical formula, P2O5). This white crystalline solid is the anhydride of phosphoric acid. It is a powerful desic ...
respectively. Diethyl sulfate is a useful ethylating agent in organic synthesis. Ethyl nitrite, prepared from the reaction of ethanol with sodium nitrite and sulfuric acid, was formerly used as a
diuretic A diuretic () is any substance that promotes diuresis, the increased production of urine. This includes forced diuresis. A diuretic tablet is sometimes colloquially called a water tablet. There are several categories of diuretics. All diuretics in ...
.


Dehydration

In the presence of acid catalysts, alcohols can be converted to alkenes such as ethanol to ethylene. Typically solid acids such as alumina are used. :   CH3CH2OH → H2C=CH2 + H2O Since water is removed from the same molecule, the reaction is known as intramolecular dehydration. Intramolecular dehydration of an alcohol requires a high temperature and the presence of an acid catalyst such as sulphuric acid. Ethylene produced from sugar-derived ethanol (primarily in Brazil) competes with ethylene produced from petrochemical feedstocks such as naphtha and ethane. At a lower temperature than that of intramolecular dehydration, intermolecular alcohol dehydration may occur producing a symmetrical ether. This is a condensation reaction. In the following example, diethyl ether is produced from ethanol: :2 CH3CH2OH → CH3CH2OCH2CH3 + H2O


Combustion

Complete combustion of ethanol forms carbon dioxide and water: :C2H5OH (l) + 3 O2 (g) → 2 CO2 (g) + 3 H2O (l); −ΔHc = 1371 kJ/mol = 29.8 kJ/g = 327 kcal/mol = 7.1 kcal/g :C2H5OH (l) + 3 O2 (g) → 2 CO2 (g) + 3 H2O (g); −ΔHc = 1236 kJ/mol = 26.8 kJ/g = 295.4 kcal/mol = 6.41 kcal/g Specific heat = 2.44 kJ/(kg·K)


Acid-base chemistry

Ethanol is a neutral molecule and the pH of a solution of ethanol in water is nearly 7.00. Ethanol can be quantitatively converted to its conjugate base, the ethoxide ion (CH3CH2O), by reaction with an alkali metal such as
sodium Sodium is a chemical element with the Symbol (chemistry), symbol Na (from Latin ''natrium'') and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is an alkali metal, being in group 1 element, group 1 of the ...
: :2 CH3CH2OH + 2 Na → 2 CH3CH2ONa + H2 or a very strong base such as
sodium hydride Sodium hydride is the chemical compound with the empirical formula NaH. This alkali metal hydride is primarily used as a strong yet combustible base (chemistry), base in organic synthesis. NaH is a saline (salt-like) hydride, composed of Na+ and ...
: :CH3CH2OH + NaH → CH3CH2ONa + H2 The acidities of water and ethanol are nearly the same, as indicated by their pKa of 15.7 and 16 respectively. Thus, sodium ethoxide and
sodium hydroxide Sodium hydroxide, also known as lye and caustic soda, is an inorganic compound with the formula NaOH. It is a white solid ionic compound consisting of sodium cations and hydroxide anions . Sodium hydroxide is a highly corrosive, caustic base (c ...
exist in an equilibrium that is closely balanced: :CH3CH2OH + NaOH CH3CH2ONa + H2O


Halogenation

Ethanol is not used industrially as a precursor to ethyl halides, but the reactions are illustrative. Ethanol reacts with hydrogen halides to produce ethyl halides such as ethyl chloride and ethyl bromide via an SN2 reaction: :CH3CH2OH + HCl → CH3CH2Cl + H2O These reactions require a catalyst such as
zinc chloride Zinc chloride is the name of Inorganic chemistry, inorganic chemical compounds with the chemical formula, formula ZnCl2 and its water of hydration, hydrates. Zinc chlorides, of which nine crystalline forms are known, are colorless or white, and ar ...
. HBr requires refluxing with a
sulfuric acid Sulfuric acid (American spelling and the preferred IUPAC name) or sulphuric acid (English in the Commonwealth of Nations, Commonwealth spelling), known in antiquity as oil of vitriol, is a mineral acid composed of the elements sulfur, oxygen ...
catalyst. Ethyl halides can, in principle, also be produced by treating ethanol with more specialized halogenating agents, such as
thionyl chloride Thionyl chloride is an inorganic compound with the chemical formula . It is a moderately Volatility (chemistry), volatile, colourless liquid with an unpleasant acrid odour. Thionyl chloride is primarily used as a Halogenation, chlorinating reagen ...
or phosphorus tribromide. :CH3CH2OH + SOCl2 → CH3CH2Cl + SO2 + HCl Upon treatment with halogens in the presence of base, ethanol gives the corresponding haloform (CHX3, where X = Cl, Br, I). This conversion is called the haloform reaction. An intermediate in the reaction with chlorine is the
aldehyde In organic chemistry, an aldehyde () is an organic compound containing a functional group with the structure . The functional group itself (without the "R" side chain) can be referred to as an aldehyde but can also be classified as a formyl group ...
called chloral, which forms chloral hydrate upon reaction with water: :4 Cl2 + CH3CH2OH → CCl3CHO + 5 HCl :CCl3CHO + H2O → CCl3C(OH)2H


Oxidation

Ethanol can be oxidized to
acetaldehyde Acetaldehyde (IUPAC systematic name ethanal) is an organic chemical compound with the formula In science, a formula is a concise way of expressing information symbolically, as in a mathematical formula or a ''chemical formula''. The informa ...
and further oxidized to
acetic acid Acetic acid , systematically named ethanoic acid , is an acidic, colourless liquid and organic compound In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon chemical bond, bond ...
, depending on the reagents and conditions. This oxidation is of no importance industrially, but in the human body, these oxidation reactions are catalyzed by the
enzyme Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different molecule ...
liver alcohol dehydrogenase. The oxidation product of ethanol, acetic acid, is a nutrient for humans, being a precursor to acetyl CoA, where the acetyl group can be spent as energy or used for biosynthesis.


Metabolism

Ethanol is similar to macronutrients such as proteins, fats, and carbohydrates in that it provides calories. When consumed and metabolized, it contributes 7 calories per gram via ethanol metabolism.


Safety

Pure ethanol will irritate the skin and eyes. Nausea,
vomiting Vomiting (also known as emesis and throwing up) is the involuntary, forceful expulsion of the contents of one's stomach through the mouth and sometimes the Human nose, nose. Vomiting can be the result of ailments like Food-poisoning, foo ...
, and intoxication are symptoms of ingestion. Long-term use by ingestion can result in serious liver damage. Atmospheric concentrations above one part per thousand are above the European Union occupational exposure limits.


History

The fermentation of sugar into ethanol is one of the earliest biotechnologies employed by humans. Ethanol has historically been identified variously as spirit of wine or ardent spirits, and as aqua vitae or aqua vita. The intoxicating effects of its consumption have been known since ancient times. Ethanol has been used by humans since prehistory as the intoxicating ingredient of
alcoholic beverage An alcoholic beverage (also called an alcoholic drink, adult beverage, or a drink) is a drink that contains ethanol Ethanol (abbr. EtOH; also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic co ...
s. Dried residue on 9,000-year-old pottery found in China suggests that
Neolithic The Neolithic period, or New Stone Age, is an Old World archaeological period and the final division of the Stone Age. It saw the Neolithic Revolution, a wide-ranging set of developments that appear to have arisen independently in several pa ...
people consumed alcoholic beverages. The inflammable nature of the exhalations of wine was already known to ancient natural philosophers such as
Aristotle Aristotle (; grc-gre, Ἀριστοτέλης ''Aristotélēs'', ; 384–322 BC) was a Greek philosopher and polymath during the Classical Greece, Classical period in Ancient Greece. Taught by Plato, he was the founder of the Peripatet ...
(384–322 BCE), Theophrastus (–287 BCE), and
Pliny the Elder Gaius Plinius Secundus (AD 23/2479), called Pliny the Elder (), was a Roman Empire, Roman author, Natural history, naturalist and Natural philosophy, natural philosopher, and naval and army commander of the early Roman Empire, and a friend of t ...
(23/24–79 CE). However, this did not immediately lead to the isolation of ethanol, even despite the development of more advanced distillation techniques in second- and third-century
Roman Egypt , conventional_long_name = Roman Egypt , common_name = Egypt , subdivision = Roman province, Province , nation = the Roman Empire , era = Late antiquity , capital = Alexandria , title_leader = Praefectus Augustalis , image_ ...
. An important recognition, first found in one of the writings attributed to Jābir ibn Ḥayyān (ninth century CE), was that by adding salt to boiling wine, which increases the wine's
relative volatility Relative volatility is a measure comparing the vapor pressures of the components in a liquid mixture of chemicals. This quantity is widely used in designing large industrial distillation processes. In effect, it indicates the ease or difficulty of u ...
, the flammability of the resulting vapors may be enhanced. The distillation of wine is attested in Arabic works attributed to al-Kindī (–873 CE) and to al-Fārābī (–950), and in the 28th book of al-Zahrāwī's (Latin: Abulcasis, 936–1013) ''Kitāb al-Taṣrīf'' (later translated into Latin as ''Liber servatoris''). In the twelfth century, recipes for the production of ''aqua ardens'' ("burning water", i.e., ethanol) by distilling wine with salt started to appear in a number of Latin works, and by the end of the thirteenth century it had become a widely known substance among Western European chemists. The works of Taddeo Alderotti (1223–1296) describe a method for concentrating ethanol involving repeated
fractional distillation Fractional distillation is the separation process, separation of a mixture into its component parts, or fraction (chemistry), fractions. Chemical compounds are separated by heating them to a temperature at which one or more fractions of the mixtur ...
through a water-cooled
still A still is an apparatus used to distillation, distill liquid mixtures by heating to selectively Boiling, boil and then cooling to Condensation, condense the vapor. A still uses the same concepts as a basic distillation apparatus, but on a much ...
, by which an ethanol purity of 90% could be obtained. The medicinal properties of ethanol were studied by Arnald of Villanova (1240–1311 CE) and John of Rupescissa (–1366), the latter of whom regarded it as a life-preserving substance able to prevent all diseases (the '' aqua vitae'' or "water of life", also called by John the '' quintessence'' of wine). In
China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's List of countries and dependencies by population, most populous country, with a Population of China, population exceeding 1.4 billion, slig ...
, archaeological evidence indicates that the true distillation of alcohol began during the Jin (1115–1234) or Southern Song (1127–1279) dynasties. A still has been found at an archaeological site in Qinglong,
Hebei Hebei or , (; Postal romanization, alternately Hopeh) is a North China, northern Provinces of China, province of China. Hebei is China's List of Chinese administrative divisions by population, sixth most populous province, with over 75 mi ...
, dating to the 12th century. In India, the true distillation of alcohol was introduced from the Middle East, and was in wide use in the
Delhi Sultanate The Delhi Sultanate was an Islamic empire based in Delhi that stretched over large parts of the Indian subcontinent for 320 years (1206–1526).
by the 14th century. In 1796, German-Russian chemist Johann Tobias Lowitz obtained pure ethanol by mixing partially purified ethanol (the alcohol-water azeotrope) with an excess of anhydrous alkali and then distilling the mixture over low heat. French chemist Antoine Lavoisier described ethanol as a compound of carbon, hydrogen, and oxygen, and in 1807 Nicolas-Théodore de Saussure determined ethanol's chemical formula. Fifty years later, Archibald Scott Couper published the structural formula of ethanol. It was one of the first structural formulas determined. Ethanol was first prepared synthetically in 1825 by
Michael Faraday Michael Faraday (; 22 September 1791 – 25 August 1867) was an English scientist who contributed to the study of electromagnetism and electrochemistry. His main discoveries include the principles underlying electromagnetic induction, ...
. He found that sulfuric acid could absorb large volumes of coal gas. He gave the resulting solution to Henry Hennell, a British chemist, who found in 1826 that it contained "sulphovinic acid" ( ethyl hydrogen sulfate). In 1828, Hennell and the French chemist Georges-Simon Serullas independently discovered that sulphovinic acid could be decomposed into ethanol. On page 368, Hennell produces ethanol from "sulfovinic acid" ( ethyl hydrogen sulfate). Thus, in 1825 Faraday had unwittingly discovered that ethanol could be produced from ethylene (a component of coal gas) by acid-catalyzed hydration, a process similar to current industrial ethanol synthesis.In 1855, the French chemist Marcellin Berthelot confirmed Faraday's discovery by preparing ethanol from pure ethylene. (Note: The chemical formulas in Berthelot's paper are wrong because chemists at that time used the wrong atomic masses for the elements; e.g., carbon (6 instead of 12), oxygen (8 instead of 16), etc.) Ethanol was used as lamp fuel in the U.S. as early as 1840, but a tax levied on industrial alcohol during the
Civil War A civil war or intrastate war is a war between organized groups within the same Sovereign state, state (or country). The aim of one side may be to take control of the country or a region, to achieve independence for a region, or to change go ...
made this use uneconomical. The tax was repealed in 1906. Use as an automotive fuel dates back to 1908, with the
Ford Model T The Ford Model T is an automobile that was produced by Ford Motor Company from October 1, 1908, to May 26, 1927. It is generally regarded as the first affordable automobile, which made car travel available to middle-class Americans. The relati ...
able to run on petrol (gasoline) or ethanol. It fuels some spirit lamps. Ethanol intended for industrial use is often produced from ethylene. Ethanol has widespread use as a solvent of substances intended for human contact or consumption, including scents, flavorings, colorings, and medicines. In chemistry, it is both a solvent and a feedstock for the synthesis of other products. It has a long history as a fuel for heat and light, and more recently as a fuel for internal combustion engines.


See also

* 1-Propanol * Butanol fuel * Ethanol-induced non-lamellar phases in phospholipids * Isopropyl alcohol * Rubbing alcohol * tert-Butyl alcohol * Timeline of alcohol fuel


References


Further reading

* . * * *


External links


Alcohol (Ethanol)
at '' The Periodic Table of Videos'' (University of Nottingham)
International Labour Organization
ethanol safety information



* ttp://webbook.nist.gov/cgi/cbook.cgi?Name=ethanol&Units=SI National Institute of Standards and Technologychemical data on ethanol
Chicago Board of Trade
news and market data on ethanol futures * Calculation o
vapor pressureliquid densitydynamic liquid viscositysurface tension
of ethanol
Ethanol History
A look into the history of ethanol


Industrial ethanol production process flow diagram using ethylene and sulphuric acid
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