Shopping on line can be easy, simple and save you lots of money. It can also take a lot of your time, frustrate you, and result in unwanted purchases. Now the same can be said for regular high street shopping, but with the vast opportunity presented by the Internet it will pay you to spend a few minutes reading this and understanding how to better optimize your Ethanol shopping experience:

1. Compare - without doubt the biggest advantage that the Ethanol offers shoppers today is the ability to compare thousands of Ethanol at a time. This is a great thing, but not necessarily all the time! Too much can be daunting at times so take advantage of the great comparison sites and where possible let them do the hard work for you.

2. Research - if it has been said it will be on the internet. Ignorance is no longer a justifiable reason for buying the wrong thing. Take the time to research in detail everything that you could possible want to know about

3. Testimonials - don't know anybody that has bought a Ethanol? Wrong! If the Ethanol is good the internet will let you know. Use the Internet as a friend and get testimonials before you buy.

4. Questions - Got a question about Ethanol then search the Forums, FAQ's, Blogs etc. Don't be afraid to ask .....

5. Reputation - Never heard of the company selling Ethanol? Don't worry, no reason why you should know every company in the world, but you know someone that does! Use the internet to find out what people are saying about Ethanol and build up a picture of their reputation for sales, returns, customer service, delivery etc.

6. Returns - still worried that even after all of the above your Ethanol wont be what you want? Check out the returns policy. There is so much competition now that someone, somewhere is bound to offer the terms that you are comfortable with.

7. Feedback - happy with your Ethanol then let people know, after all you are depending on others people input in your buying decision, so why not give a little back.

8. Security - check for the yellow padlock on the Ethanol site before you buy, and the s after http:/ /i.e. https:// = a secure site

9. Contact - got a question about Ethanol, or want to leave a comment then check out the sites contact page. Reputable companies have them and respond.

10. Payment - ready to pay for your Ethanol, then use your credit card or PayPal! Be aware of companies that don't accept them, there may be genuine reasons but given the huge amount of choice you have when buying online there is no reason at all not to buy via credit card or PayPal.

{{Chembox new| ImageFile = Ethanol-2D-skeletal.svg| ImageFile1 = Ethanol-3D-vdW.png| IUPACName = Ethanol| OtherNames = Ethyl alcohol; grain alcohol; hydroxyethane; drinking alcohol| Section1 = {{Chembox Identifiers| SMILES = CCO| CASNo = 64-17-5| RTECS = KQ6300000--> | Section2 = {{Chembox Properties| Formula = C2H5OH| MolarMass = 46.06844(232) g/mol| Appearance = colorless clear liquid| Density = 0.789 g/cm³, liquid| Solubility = Fully miscible) at 20.0 °C| Dipole = 5.64 fC·fm (1.69 [Debye) (gas)--> | Section7 = {{Chembox Hazards| FlashPt = 286.15 K (13 °C or 55.4 °F)| EUClass = Flammable (F)| NFPA-F = 3| RPhrases = | SPhrases = , , --> | Section8 = {{Chembox Related| Function = alcohols -->-->Ethanol, also known as ethyl alcohol, drinking alcohol or grain alcohol, is a flammable, colorless, slightly toxic chemical compound, and is best known as the alcohol found in alcoholic beverages. In common usage, it is often referred to simply as alcohol. Its chemical formula is variously represented as EtOH, CH3CH2OH, C2H5OH or as its empirical formula Carbon2Hydrogen6Oxygen (which it shares with dimethyl ether).

After the use of fire, fermentation of sugar into ethanol is perhaps the earliest organic reaction known to humanity, and the intoxicating effects of ethanol consumption have certainly been known since ancient times. In modern times ethanol intended for industrial use has also been produced from byproducts of petroleum refining.

Because of ethanol's ease of production and its low toxicity, it finds widespread use as a solvent for substances intended for human contact or consumption, including scents, flavorings, colorings, and medicines. In chemistry it is both an essential solvent and a fundamental feedstock for the synthesis of other products. Because it burns cleanly, ethanol has a long history as a fuel, including as a fuel for internal combustion engines.

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 Alchemy (Islam) who developed the art of distillation during the Abbasid caliphate, the most notable of whom were Geber (Geber), Al-Kindi (Alkindus) and al-Razi (Rhazes). The writings attributed to Jabir ibn Hayyan (721-815) mention the flammable vapors of boiled wine. Al-Kindi (801-873) unambiguously described the distillation of wine. Absolute ethanol was first obtained in 1796 by Johann Tobias Lowitz, by filtering distilled ethanol through Activated carbon.

Antoine Lavoisier described ethanol as a compound of carbon, hydrogen, and oxygen, and in 1808, Nicolas-Théodore de Saussure determined ethanol's chemical formula. Fifty years later Archibald Scott Couper published a structural formula for ethanol, which places ethanol among the first of chemical compounds to have its 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 catalysis hydration of ethylene in 1828, in a process similar to that used for industrial ethanol synthesis today.

Ethanol served as lamp fuel in the United States as early as 1840, although taxes levied during the Civil War on industrial alcohol rendered the practice uneconomical. The tax was not repealed until 1906, and by 1908 ethanol was used to power early Model T automobiles. With the advent of Prohibition in 1920 though, sellers of ethanol fuel were accused of being allies of moonshiners, and ethanol fuel once again faded from the public eye. The recent rise in oil prices has spurred renewed interest.

Physical properties

The 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. Ethanol, like most short-chain alcohols, is flammable, colorless, has a strong odor, and is volatile.

Ethanol is slightly more refractive than water with a refractive index of 1.36242 (at λ=589.3 nm and 18.35 °C).

Ethanol is a versatile solvent, miscible in all proportions with water and many organic solvents, including acetic acid, acetone, benzene, carbon tetrachloride, chloroform, diethyl ether, ethylene glycol, glycerol, nitromethane, pyridine, and toluene. It is also miscible with light aliphatic hydrocarbons such as pentane and hexane, as well as aliphatic chlorides such as 1,1,1-Trichloroethane and tetrachloroethylene.Merck Index of Chemicals and Drugs, 9th ed. Ethanol's miscibility with water is in contrast to longer chain alcohols (five or more carbons), whose water solubility decreases rapidly as the number of carbons increases.

Hydrogen bonding causes pure ethanol to be hygroscopic 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 hydroxide and potassium hydroxides, magnesium chloride, calcium chloride, ammonium chloride, ammonium bromide, and sodium bromide. Sodium chloride and potassium chlorides are slightly soluble in ethanol. Because the ethanol molecule also has a nonpolar end, it also dissolves nonpolar substances, including most essential oils,Merck Index of Chemicals and Drugs, 9th ed.; monographs 6575 through 6669 as well as numerous flavoring, coloring, and medicinal agents.

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 (at 15.56 °C).CRC Handbook of Chemistry, 44th ed. 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 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.

Ethanol and mixtures with water greater than about 50% ethanol 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).

Chemistry Ethanol is classified as a primary alcohol, meaning that the carbon to which its hydroxyl group is attached has at least two hydrogen atoms attached to it as well.

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 Alkoxide ion (CH3CH2O−), by reaction with an alkali metal such as sodium:

2CH3CH2OH + 2sodium → 2CH3CH2ONa + hydrogen

Halogenation

Under special conditions, ethanol reacts with hydrogen halides to produce Haloalkane such as ethyl chloride and ethyl bromide:

CH3CH2OH + hydrochloric acid → ethyl chloride + water

HCl reaction requires a catalyst such as zinc chloride.

CH3CH2OH + Hydrobromic acid → Ethyl bromide + water

HBr requires refluxing with a sulfuric acid catalyst.

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

Ester formation

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

carboxylic acid + HOCH2CH3 → ester + water

For this reaction to produce useful yields it is necessary to remove water from the reaction mixture as it is formed.

Ethanol can also form esters with inorganic acids. Diethyl sulfate and triethyl phosphate, prepared by reacting ethanol with sulfuric acid 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 acid desiccants, such as sulfuric acid, cause ethanol's dehydration to form either diethyl ether or ethylene:

2 CH3CH2OH → diethyl ether + water

CH3CH2OH → ethylene + water

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

Oxidation image:Chemistry, Combustion of Ethanol 002.jpgEthanol can be oxidized to acetaldehyde, and further oxidized to acetic acid. In the human body, these oxidation reactions are catalyzed 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 over oxidation to acetic acid, by reacting it with pyridinium chromic chloride.

Chlorination When exposed to chlorine, ethanol is both oxidized and its alpha carbon chlorinated to form the compound, chloral.

4Cl2 + C2H5OH → C2HCl3O + 5HCl

Combustion

Combustion of ethanol forms carbon dioxide and water:

C2H5OH + 3 O2 → 2 CO2 + 3 H2O

Production

Ethanol is produced both as a petrochemical, through the hydration of ethylene, and biologically, by fermentation (biochemistry) sugars with yeast.Mills, G.A.; Ecklund, E.E. " Alcohols as Components of Transportation Fuels." Annual Review of Energy. November 1987. Vol. 12, 47-80. Retrieved on September 2, 2007. Which process is more economical is dependent upon the prevailing prices of petroleum and of grain feed stocks.

Ethylene hydration Ethanol for use as industrial feedstock is most often made from petrochemical feed stocks, typically by the acid-catalysis hydration of ethylene, represented by the chemical equation

ethylene(g) + water(g) → CH3CH2OH(l)

The catalyst is most commonly phosphoric acid, adsorption 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.Lodgsdon, J.E. (1994). "Ethanol." In J.I. Kroschwitz (Ed.) Encyclopedia of Chemical Technology, 4th ed. vol. 9, p. 820. New York: John Wiley & Sons. The reaction is carried out at with an excess of high pressure steam at 300 °C.

In an older process, first practiced on the industrial scale in 1930 by Union Carbide,Lodgsdon, J.E. (1994). p. 817 but now almost entirely obsolete, ethylene was hydrated indirectly by reacting it with concentrated sulfuric acid to produce ethyl sulfate, which was then hydrolysis to yield ethanol and regenerate the sulfuric acid:

ethylene + sulfuric acid → ethyl sulfate

ethyl sulfate + water → CH3CH2OH + sulfuric acid

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, metabolism polysaccharide in the absence of oxygen, they produce ethanol and carbon dioxide. The chemical equation below summarizes the conversion:

glucose → 2 CH3CH2OH + 2 carbon dioxide

The process of culturing yeast under conditions to produce alcohol is called as brewing. Ethanol's toxicity to yeast limits the ethanol concentration obtainable by brewing. The most ethanol-tolerant strains of yeast can survive up to approximately 15% ethanol by volume.Morais, P.B.; Rosa, C.A.; Linardi, V.R.; Carazza, F.; Nonato, E.A. " Production of fuel alcohol by Saccharomyces strains from tropical habitats." Biotechnology Letters. November 1996. Vol. 18, No. 11, 1351-1356. Retrieved on September 2, 2007.

The fermentation process must exclude oxygen. If oxygen is present, yeast undergo aerobic respiration which produces carbon dioxide and water rather than ethanol.

In order to produce ethanol from starchy materials such as cereal grains, the starch must first be converted into sugars. In brewing beer, this has traditionally been accomplished by allowing the grain to germinate, or malt, which produces the enzyme, amylase. When the malted grain is mashing, the amylase converts the remaining starches into sugars. For fuel ethanol, the hydrolysis of starch into glucose can be accomplished more rapidly by treatment with dilute sulfuric acid, fungi produced amylase, or some combination of the two.Badger, P.C. " Ethanol From Cellulose: A General Review." p. 17–21. In: J. Janick and A. Whipkey (eds.), Trends in new crops and new uses. ASHS Press, 2002, Alexandria, VA. Retrieved on September 2, 2007.

Cellulosic ethanol Sugars for ethanol fermentation can be obtained from cellulose. Until recently, however, the cost of the cellulase enzymes capable of hydrolyzing cellulose has been prohibitive. The Canada firm, Iogen, brought the first cellulose-based ethanol plant on-stream in 2004.Ritter, S.K. (May 31 2004). "Biomass or Bust." Chemical & Engineering News 82(22), 31–34. Its primary consumer so far has been the Canadian government, which, along with the United States Department of Energy, has invested heavily in the commercialization of cellulosic ethanol. Deployment of this technology could turn a number of cellulose-containing agricultural byproducts, such as corncobs, straw, and sawdust, into renewable energy resources. Other enzyme companies are developing genetically engineered fungi that produce large volumes of cellulase, xylanase and hemicellulase enzymes. These would convert agricultural residues such as corn stover, wheat straw and sugar cane bagasse and energy crops such as switchgrass into fermentable sugars.

Cellulose-bearing materials typically also contain other polysaccharides, including hemicellulose. When hydrolysis, hemicellulose decomposes 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 ferment xylose and other pentoses into ethanol.

Prospective technologies The anaerobic bacteria 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.

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.Rapier, R. (June 26 2006) "E3 Biofuels: Responsible Ethanol" R-Squared Energy Blog

Though in an early stage of research, there is some development of alternative production methods that use feed stocks such as municipal waste or recycled products, rice hulls, sugarcane bagasse, small diameter trees, wood chips, and switchgrass.

Testing of liquid ethanol.Breweries and biofuel plants employ two methods for measuring ethanol concentration. Infrared ethanol sensors measure the vibrational frequency of dissolved ethanol using the CH band at 2900 cm−1. This method uses a relatively inexpensive solid state sensor that compares the CH 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 Ethylene hydration or brewing produces an ethanol-water mixture. For most industrial and fuel uses, the ethanol must be purified. Fractional distillation can concentrate ethanol to 95.6% by weight (89.5 mole%). This mixture is an azeotrope with a boiling point of 78.1 °C, and cannot be further purified by distillation.

In one common industrial method to obtain absolute alcohol, a small quantity of benzene is added to rectified spirit and the mixture is then distilled. Absolute alcohol is obtained in the third fraction, which distills over at 78.3 degree Celsius (351.4 kelvin). 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.

Other methods for obtaining absolute ethanol include desiccation using adsorbents such as starch or zeolites, which adsorb water preferentially, as well as azeotropic distillation and extractive distillation.


Types of ethanol Alcoholic beverages Distilled alcoholic beverages are usually distilled to a high purity and then diluted. However, in some countries such as Poland, rectified spirit (95-96%) is sold directly to the consumer, for human consumption. Also, vodka is rectified spirit diluted to 37.5-60% alcohol by volume.

Denatured alcohol Pure ethanol and alcoholic beverages are heavily taxed. Ethanol has many applications that do not involve human consumption. To relieve the tax burden on these application, most jurisdictions waive the tax when agents have been added to the ethanol to render it unfit for human consumption. These include bittering agents such as denatonium benzoate, as well as toxins such as methanol, naphtha, and pyridine.Great Britain (2005). The Denatured Alcohol Regulations 2005. Statutory Instrument 2005 No. 1524.

Absolute ethanol Absolute or anhydrous alcohol generally refers to purified ethanol, containing no more than one percent water. Absolute alcohol not intended for human consumption often contains trace amounts of toxic benzene.

Pure ethanol is classed as 200 Proof (alcohol) in the USA, equivalent to 175 degrees proof in the (now rarely used) UK system.

Neutralized ethanol Ethanol for analytic purposes is said to be neutralized when potassium hydroxide or sodium hydroxide is added to ethanol containing a pH indicator, such phenolphthalein, until its color begins to turn. The solution can then be used in a titration to determine the pH of a test solution.

Use As a fuel {| class="wikitable" align="right"! align = "left"|Fuel type! align ="right"|     MJ/l! align ="right"|     MJ/kg! align ="right"|octane rating|-|ethanol fuel| align ="right"|23.5| align ="right"|31.1Calculated from heats of formation. Does not correspond exactly to the figure for MJ/l divided by density.| align ="right"|129|-| Methanol| align ="right"|Min 91|-| Premium Gasoline| align ="right"|| align ="right"|| align ="right"|Min 95|-| [Aviation gasoline
(high octane gasoline, not Jet fuel)]
(10% ethanol + 90% gasoline)| align ="right"|33.7| align ="right"|| align ="right"|93/94|-| Autogas (Liquified petroleum gas)
(60% Propane + 40% Butane)]| align ="right"|25.3| align ="right"|~55| align ="right"||-| Diesel of some fuels compared with ethanol: Appendix B, Transportation Energy Data Book from the [Center for Transportation Analysis of the Oak Ridge National Laboratory
] and fuel additive. The largest national fuel ethanol industries exist in Brazil (gasoline sold in Brazil contains at least 20% ethanol and hydrous ethanol is also used as fuel).Reel, M. (August 19 2006) "Brazil's Road to Energy Independence" The Washington Post.

Today, almost half of Brazilian cars are able to use 100% ethanol as fuel, which includes ethanol-only engines and Flexible-fuel vehicle engines. Flex-fuel engines are able to work with all ethanol, all gasoline, or any mixture of both. Brazil supports this population of ethanol-burning automobiles with large national infrastructure that produces ethanol from domestically grown sugar cane. Sugar cane 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 wasted, but is utilized in power plants as a surprisingly efficient fuel to produce electricity.

World production of ethanol in 2006 was 51 billion liters, (13.5 billion gallons), with 69% of the world supply coming from Brazil and the United States.

The United States fuel ethanol industry is based largely on maize. 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 per year. 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 believed that a material portion of the ~150 billion gallon per year market for gasoline will begin to be replaced with fuel ethanol.

The Energy Policy Act of 2005 requires that 4 billion gallons of "renewable fuel" be used in 2006 and this requirement will grow to a yearly production of 7.5 billion gallons by 2012.

"fueled by clean burning ethanol" owned by New York City.In the United States, ethanol is most commonly blended with gasoline as a 10% ethanol blend nicknamed "gasohol". This blend is widely sold throughout the U.S. Midwest, and in cities required by the 1990 Clean Air Act to oxygenate their gasoline during the winter.

Controversy As reported in "The Energy Balance of Corn Ethanol: an Update," the energy returned on energy invested EROEI for ethanol made from corn in the U.S. is 1.34 (it yields 34% more energy than it takes to produce it). Input energy includes natural gas based fertilizers, farm equipment, transformation from corn or other materials, and transportation. However, other researchers report that the production of ethanol consumes more energy than it yields.

Lately criticism and controversy has been growing over the massive subsidies that some companies have been receiving for ethanol production, including "the bulk of the more than $10 billion in subsidies to Archer-Daniels-Midland since 1980," according to the CATO institute. Recent articles have also blamed subsidized ethanol production for the nearly 200% increase in milk prices since 2004, although that is disputed by some.

Oil has historically had a much higher EROEI than agriculturally produced ethanol, especially from petroleum deposits accessible by land, but also from those that only offshore drilling rigs can reach. Apart from this, the amount of ethanol needed to run the United States, for example, is greater than its own farmland could produce, even if fields now used for food were converted for production of non-food-grade corn. It has been estimated that "if every bushel of U.S. corn, wheat, rice and soybean were used to produce ethanol, it would only cover about 4% of Energy_policy_of_the_United_States on a net basis."

In the United States, preferential regulatory and tax treatment of ethanol automotive fuels introduces complexities beyond its energy economics alone. North American automakers have in 2006 and 2007 promoted a blend of 85% ethanol and 15% gasoline, marketed as E85, and their Flexible-fuel vehicle, e.g. General Motors " Live Green, Go Yellow" campaign. The apparent motivation is the nature of U.S. CAFE standards, which give an effective 54% fuel efficiency bonus to vehicles capable of running on 85% alcohol blends over vehicles not adapted to run on 85% alcohol blends. In addition to this auto manufacturer-driven impetus for 85% alcohol blends, the United States Environmental Protection Agency had authority to mandate that minimum proportions of oxygenates be added to automotive gasoline on regional and seasonal bases from 1992 until 2006 in an attempt to reduce air pollution, in particular ground-level ozone and smog. As a consequence, much gasoline sold in the United States is blended with up to 10% of an unspecified oxygenating agent. In United States, incidents of methyl tert(iary)-butyl ether (MTBE) groundwater contamination in the majority of the 50 states, and the State of California's ban on the use of MTBE as a gasoline additive has allowed ethanol to displace it as the most common fuel oxygenate.

Rocket fuel Ethanol was commonly used as fuel in early bipropellant rocket vehicles, in conjunction with an oxidizer such as liquid oxygen. The German V-2 rocket of World War II, credited with beginning the space age, used ethanol, mixed with water to reduce the combustion chamber temperature.Braeunig, Robert A. "Rocket Propellants." (Website). Rocket & Space Technology, 2006. Retrieved on 2007-08-23. The V-2's design team helped develop U.S. rockets following World War II, including the ethanol-fueled Redstone (rocket), which launched the first U.S. satellite. "A Brief History of Rocketry." NASA Historical Archive, via science.ksc.nasa.gov. Alcohols fell into general disuse as more efficient rocket fuels were developed.

Alcoholic beverages Ethanol is the principal psychoactive constituent in alcoholic beverages, with depressant effects to the central nervous system. It has a complex mode of action and affects multiple systems in the brain. Similar psychoactives include those which also interact with GABA receptors, such as gamma-hydroxybutyric acid.

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.

Distilled beverages are made by distilling fermented beverages. Broad categories of distilled beverages include whiskeys, distilled from fermented cereal grains; brandy, 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 are 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 flavors from fruits, herbs, and spices into distilled spirits. A traditional example is gin, which is created by infusing juniper berries into a neutral grain alcohol.

In a few beverages, ethanol is concentrated by means other than distillation. Applejack (beverage) is traditionally made by freeze distillation, by which water is frozen out of fermented apple cider, leaving a more ethanol-rich liquid behind. Eisbier (more commonly, eisbock) is also freeze-distilled, with beer as the base beverage. 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 are often sweeter than other wines.

Alcoholic beverages are sometimes used in cooking, not only for their inherent flavors, but also because the alcohol dissolves hydrophobic flavor compounds which water cannot.

Feedstock Ethanol is an important industrial ingredient and has widespread use as a base chemical for other organic compounds. These include ethyl halides, ethyl esters, diethyl ether, acetic acid, butadiene, and ethyl amines.

Antiseptic use 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. Ethanol kills organisms by denaturing their proteins and dissolving their lipids and is effective against most bacterium and fungus, and many viruses, but is ineffective against bacterial spores.

Antidote Although ethanol is a poison, it is sometimes used as an antidote for poisoning by other, more toxic alcohols, in particular methanol and ethylene glycol. Ethanol competitive inhibition with other alcohols for the alcohol dehydrogenase enzyme, preventing metabolism into toxic aldehyde and carboxylic acid derivatives.

Other uses

Metabolism and toxicology {| align="right" width="250 px" class="wikitable"! BAC (mg/dL) !! SymptomsPohorecky, L.A., and J. Brick. (1988). "Pharmacology of ethanol." Pharmacology & Therapeutics 36(3), 335-427.|-| 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 || Expiration|}

Pure ethanol is a tasteless liquid with a strong and distinctive odor that produces a characteristic heat-like sensation when brought into contact with the tongue or mucous membranes. Ethanol adds a distinctive taste to drinks. 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.

Ethanol is a central nervous system depressant and has significant psychoactive effects in sublethal doses; for specifics, see Effects of alcohol on the body#Effects by dose. Based on its abilities to change the human consciousness, ethanol is considered a drug. "Alcohol Use" MedlinePlus Medical Encyclopedia, U.S. National Library of Medicine and National Institutes of Health. Retrieved on 2007-09-27 Death from ethyl alcohol consumption is possible when blood alcohol level reaches 0.4%. A blood level of 0.5% or more is commonly fatal. Levels of even less than 0.1% can cause intoxication, with unconsciousness often occurring at 0.3-0.4%.

In America, about half of the deaths in car accidents occur in alcohol-related crashes. There is no completely safe level of alcohol for driving, since the risk of a fatal car accident rises exponentially with the level of alcohol in the driver's blood. However, most drunk driving laws governing the acceptable levels in the blood while driving or operating heavy machinery set typical upper limits of between 0.05% or 0.08%.

Ethanol interacts in harmful ways with a number of other drugs, including barbiturates, benzodiazepines, narcotics, and phenothiazines

Metabolism Ethanol within the human body is converted into acetaldehyde by alcohol dehydrogenase and then into acetic acid by acetaldehyde dehydrogenase. The product of the first step of this breakdown, acetaldehyde, is more toxic than ethanol. Acetaldehyde is linked to most of the clinical effects of alcohol. It has been shown to increase the risk of contracting cirrhosis of the liver, multiple forms of cancer, and alcoholism.

Magnitude of effect 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 drug tolerance have a greater quantity of these enzymes, and metabolize ethanol more rapidly.

The amount of ethanol in the body is typically quantified 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 judgement. At higher dosages (BAC > 100 mg/dl), 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.

Frequent use of alcoholic beverages has also been shown to be a major contributing factor in cases of elevated blood levels of triglycerides.{{cite web|url=http://www.americanheart.org/presenter.jhtml?identifier=4778|title=Triglycerides|accessdate=2007-09-04|publisher=American Heart Association-->

See also

References Further reading

External links

{{Chembox new| ImageFile = Ethanol-2D-skeletal.svg| ImageFile1 = Ethanol-3D-vdW.png| IUPACName = Ethanol| OtherNames = Ethyl alcohol; grain alcohol; hydroxyethane; drinking alcohol| Section1 = {{Chembox Identifiers| SMILES = CCO| CASNo = 64-17-5| RTECS = KQ6300000--> | Section2 = {{Chembox Properties| Formula = C2H5OH| MolarMass = 46.06844(232) g/mol| Appearance = colorless clear liquid| Density = 0.789 g/cm³, liquid| Solubility = Fully miscible) at 20.0 °C| Dipole = 5.64 fC·fm (1.69 [Debye) (gas)--> | Section7 = {{Chembox Hazards| FlashPt = 286.15 K (13 °C or 55.4 °F)| EUClass = Flammable (F)| NFPA-F = 3| RPhrases = | SPhrases = , , --> | Section8 = {{Chembox Related| Function = alcohols -->-->Ethanol, also known as ethyl alcohol, drinking alcohol or grain alcohol, is a flammable, colorless, slightly toxic chemical compound, and is best known as the alcohol found in alcoholic beverages. In common usage, it is often referred to simply as alcohol. Its chemical formula is variously represented as EtOH, CH3CH2OH, C2H5OH or as its empirical formula Carbon2Hydrogen6Oxygen (which it shares with dimethyl ether).

After the use of fire, fermentation of sugar into ethanol is perhaps the earliest organic reaction known to humanity, and the intoxicating effects of ethanol consumption have certainly been known since ancient times. In modern times ethanol intended for industrial use has also been produced from byproducts of petroleum refining.

Because of ethanol's ease of production and its low toxicity, it finds widespread use as a solvent for substances intended for human contact or consumption, including scents, flavorings, colorings, and medicines. In chemistry it is both an essential solvent and a fundamental feedstock for the synthesis of other products. Because it burns cleanly, ethanol has a long history as a fuel, including as a fuel for internal combustion engines.

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 Alchemy (Islam) who developed the art of distillation during the Abbasid caliphate, the most notable of whom were Geber (Geber), Al-Kindi (Alkindus) and al-Razi (Rhazes). The writings attributed to Jabir ibn Hayyan (721-815) mention the flammable vapors of boiled wine. Al-Kindi (801-873) unambiguously described the distillation of wine. Absolute ethanol was first obtained in 1796 by Johann Tobias Lowitz, by filtering distilled ethanol through Activated carbon.

Antoine Lavoisier described ethanol as a compound of carbon, hydrogen, and oxygen, and in 1808, Nicolas-Théodore de Saussure determined ethanol's chemical formula. Fifty years later Archibald Scott Couper published a structural formula for ethanol, which places ethanol among the first of chemical compounds to have its 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 catalysis hydration of ethylene in 1828, in a process similar to that used for industrial ethanol synthesis today.

Ethanol served as lamp fuel in the United States as early as 1840, although taxes levied during the Civil War on industrial alcohol rendered the practice uneconomical. The tax was not repealed until 1906, and by 1908 ethanol was used to power early Model T automobiles. With the advent of Prohibition in 1920 though, sellers of ethanol fuel were accused of being allies of moonshiners, and ethanol fuel once again faded from the public eye. The recent rise in oil prices has spurred renewed interest.

Physical properties

The 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. Ethanol, like most short-chain alcohols, is flammable, colorless, has a strong odor, and is volatile.

Ethanol is slightly more refractive than water with a refractive index of 1.36242 (at λ=589.3 nm and 18.35 °C).

Ethanol is a versatile solvent, miscible in all proportions with water and many organic solvents, including acetic acid, acetone, benzene, carbon tetrachloride, chloroform, diethyl ether, ethylene glycol, glycerol, nitromethane, pyridine, and toluene. It is also miscible with light aliphatic hydrocarbons such as pentane and hexane, as well as aliphatic chlorides such as 1,1,1-Trichloroethane and tetrachloroethylene.Merck Index of Chemicals and Drugs, 9th ed. Ethanol's miscibility with water is in contrast to longer chain alcohols (five or more carbons), whose water solubility decreases rapidly as the number of carbons increases.

Hydrogen bonding causes pure ethanol to be hygroscopic 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 hydroxide and potassium hydroxides, magnesium chloride, calcium chloride, ammonium chloride, ammonium bromide, and sodium bromide. Sodium chloride and potassium chlorides are slightly soluble in ethanol. Because the ethanol molecule also has a nonpolar end, it also dissolves nonpolar substances, including most essential oils,Merck Index of Chemicals and Drugs, 9th ed.; monographs 6575 through 6669 as well as numerous flavoring, coloring, and medicinal agents.

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 (at 15.56 °C).CRC Handbook of Chemistry, 44th ed. 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 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.

Ethanol and mixtures with water greater than about 50% ethanol 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).

Chemistry Ethanol is classified as a primary alcohol, meaning that the carbon to which its hydroxyl group is attached has at least two hydrogen atoms attached to it as well.

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 Alkoxide ion (CH3CH2O−), by reaction with an alkali metal such as sodium:

2CH3CH2OH + 2sodium → 2CH3CH2ONa + hydrogen

Halogenation

Under special conditions, ethanol reacts with hydrogen halides to produce Haloalkane such as ethyl chloride and ethyl bromide:

CH3CH2OH + hydrochloric acid → ethyl chloride + water

HCl reaction requires a catalyst such as zinc chloride.

CH3CH2OH + Hydrobromic acid → Ethyl bromide + water

HBr requires refluxing with a sulfuric acid catalyst.

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

Ester formation

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

carboxylic acid + HOCH2CH3 → ester + water

For this reaction to produce useful yields it is necessary to remove water from the reaction mixture as it is formed.

Ethanol can also form esters with inorganic acids. Diethyl sulfate and triethyl phosphate, prepared by reacting ethanol with sulfuric acid 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 acid desiccants, such as sulfuric acid, cause ethanol's dehydration to form either diethyl ether or ethylene:

2 CH3CH2OH → diethyl ether + water

CH3CH2OH → ethylene + water

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

Oxidation image:Chemistry, Combustion of Ethanol 002.jpgEthanol can be oxidized to acetaldehyde, and further oxidized to acetic acid. In the human body, these oxidation reactions are catalyzed 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 over oxidation to acetic acid, by reacting it with pyridinium chromic chloride.

Chlorination When exposed to chlorine, ethanol is both oxidized and its alpha carbon chlorinated to form the compound, chloral.

4Cl2 + C2H5OH → C2HCl3O + 5HCl

Combustion

Combustion of ethanol forms carbon dioxide and water:

C2H5OH + 3 O2 → 2 CO2 + 3 H2O

Production

Ethanol is produced both as a petrochemical, through the hydration of ethylene, and biologically, by fermentation (biochemistry) sugars with yeast.Mills, G.A.; Ecklund, E.E. " Alcohols as Components of Transportation Fuels." Annual Review of Energy. November 1987. Vol. 12, 47-80. Retrieved on September 2, 2007. Which process is more economical is dependent upon the prevailing prices of petroleum and of grain feed stocks.

Ethylene hydration Ethanol for use as industrial feedstock is most often made from petrochemical feed stocks, typically by the acid-catalysis hydration of ethylene, represented by the chemical equation

ethylene(g) + water(g) → CH3CH2OH(l)

The catalyst is most commonly phosphoric acid, adsorption 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.Lodgsdon, J.E. (1994). "Ethanol." In J.I. Kroschwitz (Ed.) Encyclopedia of Chemical Technology, 4th ed. vol. 9, p. 820. New York: John Wiley & Sons. The reaction is carried out at with an excess of high pressure steam at 300 °C.

In an older process, first practiced on the industrial scale in 1930 by Union Carbide,Lodgsdon, J.E. (1994). p. 817 but now almost entirely obsolete, ethylene was hydrated indirectly by reacting it with concentrated sulfuric acid to produce ethyl sulfate, which was then hydrolysis to yield ethanol and regenerate the sulfuric acid:

ethylene + sulfuric acid → ethyl sulfate

ethyl sulfate + water → CH3CH2OH + sulfuric acid

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, metabolism polysaccharide in the absence of oxygen, they produce ethanol and carbon dioxide. The chemical equation below summarizes the conversion:

glucose → 2 CH3CH2OH + 2 carbon dioxide

The process of culturing yeast under conditions to produce alcohol is called as brewing. Ethanol's toxicity to yeast limits the ethanol concentration obtainable by brewing. The most ethanol-tolerant strains of yeast can survive up to approximately 15% ethanol by volume.Morais, P.B.; Rosa, C.A.; Linardi, V.R.; Carazza, F.; Nonato, E.A. " Production of fuel alcohol by Saccharomyces strains from tropical habitats." Biotechnology Letters. November 1996. Vol. 18, No. 11, 1351-1356. Retrieved on September 2, 2007.

The fermentation process must exclude oxygen. If oxygen is present, yeast undergo aerobic respiration which produces carbon dioxide and water rather than ethanol.

In order to produce ethanol from starchy materials such as cereal grains, the starch must first be converted into sugars. In brewing beer, this has traditionally been accomplished by allowing the grain to germinate, or malt, which produces the enzyme, amylase. When the malted grain is mashing, the amylase converts the remaining starches into sugars. For fuel ethanol, the hydrolysis of starch into glucose can be accomplished more rapidly by treatment with dilute sulfuric acid, fungi produced amylase, or some combination of the two.Badger, P.C. " Ethanol From Cellulose: A General Review." p. 17–21. In: J. Janick and A. Whipkey (eds.), Trends in new crops and new uses. ASHS Press, 2002, Alexandria, VA. Retrieved on September 2, 2007.

Cellulosic ethanol Sugars for ethanol fermentation can be obtained from cellulose. Until recently, however, the cost of the cellulase enzymes capable of hydrolyzing cellulose has been prohibitive. The Canada firm, Iogen, brought the first cellulose-based ethanol plant on-stream in 2004.Ritter, S.K. (May 31 2004). "Biomass or Bust." Chemical & Engineering News 82(22), 31–34. Its primary consumer so far has been the Canadian government, which, along with the United States Department of Energy, has invested heavily in the commercialization of cellulosic ethanol. Deployment of this technology could turn a number of cellulose-containing agricultural byproducts, such as corncobs, straw, and sawdust, into renewable energy resources. Other enzyme companies are developing genetically engineered fungi that produce large volumes of cellulase, xylanase and hemicellulase enzymes. These would convert agricultural residues such as corn stover, wheat straw and sugar cane bagasse and energy crops such as switchgrass into fermentable sugars.

Cellulose-bearing materials typically also contain other polysaccharides, including hemicellulose. When hydrolysis, hemicellulose decomposes 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 ferment xylose and other pentoses into ethanol.

Prospective technologies The anaerobic bacteria 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.

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.Rapier, R. (June 26 2006) "E3 Biofuels: Responsible Ethanol" R-Squared Energy Blog

Though in an early stage of research, there is some development of alternative production methods that use feed stocks such as municipal waste or recycled products, rice hulls, sugarcane bagasse, small diameter trees, wood chips, and switchgrass.

Testing of liquid ethanol.Breweries and biofuel plants employ two methods for measuring ethanol concentration. Infrared ethanol sensors measure the vibrational frequency of dissolved ethanol using the CH band at 2900 cm−1. This method uses a relatively inexpensive solid state sensor that compares the CH 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 Ethylene hydration or brewing produces an ethanol-water mixture. For most industrial and fuel uses, the ethanol must be purified. Fractional distillation can concentrate ethanol to 95.6% by weight (89.5 mole%). This mixture is an azeotrope with a boiling point of 78.1 °C, and cannot be further purified by distillation.

In one common industrial method to obtain absolute alcohol, a small quantity of benzene is added to rectified spirit and the mixture is then distilled. Absolute alcohol is obtained in the third fraction, which distills over at 78.3 degree Celsius (351.4 kelvin). 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.

Other methods for obtaining absolute ethanol include desiccation using adsorbents such as starch or zeolites, which adsorb water preferentially, as well as azeotropic distillation and extractive distillation.


Types of ethanol Alcoholic beverages Distilled alcoholic beverages are usually distilled to a high purity and then diluted. However, in some countries such as Poland, rectified spirit (95-96%) is sold directly to the consumer, for human consumption. Also, vodka is rectified spirit diluted to 37.5-60% alcohol by volume.

Denatured alcohol Pure ethanol and alcoholic beverages are heavily taxed. Ethanol has many applications that do not involve human consumption. To relieve the tax burden on these application, most jurisdictions waive the tax when agents have been added to the ethanol to render it unfit for human consumption. These include bittering agents such as denatonium benzoate, as well as toxins such as methanol, naphtha, and pyridine.Great Britain (2005). The Denatured Alcohol Regulations 2005. Statutory Instrument 2005 No. 1524.

Absolute ethanol Absolute or anhydrous alcohol generally refers to purified ethanol, containing no more than one percent water. Absolute alcohol not intended for human consumption often contains trace amounts of toxic benzene.

Pure ethanol is classed as 200 Proof (alcohol) in the USA, equivalent to 175 degrees proof in the (now rarely used) UK system.

Neutralized ethanol Ethanol for analytic purposes is said to be neutralized when potassium hydroxide or sodium hydroxide is added to ethanol containing a pH indicator, such phenolphthalein, until its color begins to turn. The solution can then be used in a titration to determine the pH of a test solution.

Use As a fuel {| class="wikitable" align="right"! align = "left"|Fuel type! align ="right"|     MJ/l! align ="right"|     MJ/kg! align ="right"|octane rating|-|ethanol fuel| align ="right"|23.5| align ="right"|31.1Calculated from heats of formation. Does not correspond exactly to the figure for MJ/l divided by density.| align ="right"|129|-| Methanol| align ="right"|Min 91|-| Premium Gasoline| align ="right"|| align ="right"|| align ="right"|Min 95|-| [Aviation gasoline
(high octane gasoline, not Jet fuel)]
(10% ethanol + 90% gasoline)| align ="right"|33.7| align ="right"|| align ="right"|93/94|-| Autogas (Liquified petroleum gas)
(60% Propane + 40% Butane)]| align ="right"|25.3| align ="right"|~55| align ="right"||-| Diesel of some fuels compared with ethanol: Appendix B, Transportation Energy Data Book from the [Center for Transportation Analysis of the Oak Ridge National Laboratory
] and fuel additive. The largest national fuel ethanol industries exist in Brazil (gasoline sold in Brazil contains at least 20% ethanol and hydrous ethanol is also used as fuel).Reel, M. (August 19 2006) "Brazil's Road to Energy Independence" The Washington Post.

Today, almost half of Brazilian cars are able to use 100% ethanol as fuel, which includes ethanol-only engines and Flexible-fuel vehicle engines. Flex-fuel engines are able to work with all ethanol, all gasoline, or any mixture of both. Brazil supports this population of ethanol-burning automobiles with large national infrastructure that produces ethanol from domestically grown sugar cane. Sugar cane 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 wasted, but is utilized in power plants as a surprisingly efficient fuel to produce electricity.

World production of ethanol in 2006 was 51 billion liters, (13.5 billion gallons), with 69% of the world supply coming from Brazil and the United States.

The United States fuel ethanol industry is based largely on maize. 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 per year. 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 believed that a material portion of the ~150 billion gallon per year market for gasoline will begin to be replaced with fuel ethanol.

The Energy Policy Act of 2005 requires that 4 billion gallons of "renewable fuel" be used in 2006 and this requirement will grow to a yearly production of 7.5 billion gallons by 2012.

"fueled by clean burning ethanol" owned by New York City.In the United States, ethanol is most commonly blended with gasoline as a 10% ethanol blend nicknamed "gasohol". This blend is widely sold throughout the U.S. Midwest, and in cities required by the 1990 Clean Air Act to oxygenate their gasoline during the winter.

Controversy As reported in "The Energy Balance of Corn Ethanol: an Update," the energy returned on energy invested EROEI for ethanol made from corn in the U.S. is 1.34 (it yields 34% more energy than it takes to produce it). Input energy includes natural gas based fertilizers, farm equipment, transformation from corn or other materials, and transportation. However, other researchers report that the production of ethanol consumes more energy than it yields.

Lately criticism and controversy has been growing over the massive subsidies that some companies have been receiving for ethanol production, including "the bulk of the more than $10 billion in subsidies to Archer-Daniels-Midland since 1980," according to the CATO institute. Recent articles have also blamed subsidized ethanol production for the nearly 200% increase in milk prices since 2004, although that is disputed by some.

Oil has historically had a much higher EROEI than agriculturally produced ethanol, especially from petroleum deposits accessible by land, but also from those that only offshore drilling rigs can reach. Apart from this, the amount of ethanol needed to run the United States, for example, is greater than its own farmland could produce, even if fields now used for food were converted for production of non-food-grade corn. It has been estimated that "if every bushel of U.S. corn, wheat, rice and soybean were used to produce ethanol, it would only cover about 4% of Energy_policy_of_the_United_States on a net basis."

In the United States, preferential regulatory and tax treatment of ethanol automotive fuels introduces complexities beyond its energy economics alone. North American automakers have in 2006 and 2007 promoted a blend of 85% ethanol and 15% gasoline, marketed as E85, and their Flexible-fuel vehicle, e.g. General Motors " Live Green, Go Yellow" campaign. The apparent motivation is the nature of U.S. CAFE standards, which give an effective 54% fuel efficiency bonus to vehicles capable of running on 85% alcohol blends over vehicles not adapted to run on 85% alcohol blends. In addition to this auto manufacturer-driven impetus for 85% alcohol blends, the United States Environmental Protection Agency had authority to mandate that minimum proportions of oxygenates be added to automotive gasoline on regional and seasonal bases from 1992 until 2006 in an attempt to reduce air pollution, in particular ground-level ozone and smog. As a consequence, much gasoline sold in the United States is blended with up to 10% of an unspecified oxygenating agent. In United States, incidents of methyl tert(iary)-butyl ether (MTBE) groundwater contamination in the majority of the 50 states, and the State of California's ban on the use of MTBE as a gasoline additive has allowed ethanol to displace it as the most common fuel oxygenate.

Rocket fuel Ethanol was commonly used as fuel in early bipropellant rocket vehicles, in conjunction with an oxidizer such as liquid oxygen. The German V-2 rocket of World War II, credited with beginning the space age, used ethanol, mixed with water to reduce the combustion chamber temperature.Braeunig, Robert A. "Rocket Propellants." (Website). Rocket & Space Technology, 2006. Retrieved on 2007-08-23. The V-2's design team helped develop U.S. rockets following World War II, including the ethanol-fueled Redstone (rocket), which launched the first U.S. satellite. "A Brief History of Rocketry." NASA Historical Archive, via science.ksc.nasa.gov. Alcohols fell into general disuse as more efficient rocket fuels were developed.

Alcoholic beverages Ethanol is the principal psychoactive constituent in alcoholic beverages, with depressant effects to the central nervous system. It has a complex mode of action and affects multiple systems in the brain. Similar psychoactives include those which also interact with GABA receptors, such as gamma-hydroxybutyric acid.

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.

Distilled beverages are made by distilling fermented beverages. Broad categories of distilled beverages include whiskeys, distilled from fermented cereal grains; brandy, 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 are 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 flavors from fruits, herbs, and spices into distilled spirits. A traditional example is gin, which is created by infusing juniper berries into a neutral grain alcohol.

In a few beverages, ethanol is concentrated by means other than distillation. Applejack (beverage) is traditionally made by freeze distillation, by which water is frozen out of fermented apple cider, leaving a more ethanol-rich liquid behind. Eisbier (more commonly, eisbock) is also freeze-distilled, with beer as the base beverage. 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 are often sweeter than other wines.

Alcoholic beverages are sometimes used in cooking, not only for their inherent flavors, but also because the alcohol dissolves hydrophobic flavor compounds which water cannot.

Feedstock Ethanol is an important industrial ingredient and has widespread use as a base chemical for other organic compounds. These include ethyl halides, ethyl esters, diethyl ether, acetic acid, butadiene, and ethyl amines.

Antiseptic use 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. Ethanol kills organisms by denaturing their proteins and dissolving their lipids and is effective against most bacterium and fungus, and many viruses, but is ineffective against bacterial spores.

Antidote Although ethanol is a poison, it is sometimes used as an antidote for poisoning by other, more toxic alcohols, in particular methanol and ethylene glycol. Ethanol competitive inhibition with other alcohols for the alcohol dehydrogenase enzyme, preventing metabolism into toxic aldehyde and carboxylic acid derivatives.

Other uses

Metabolism and toxicology {| align="right" width="250 px" class="wikitable"! BAC (mg/dL) !! SymptomsPohorecky, L.A., and J. Brick. (1988). "Pharmacology of ethanol." Pharmacology & Therapeutics 36(3), 335-427.|-| 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 || Expiration|}

Pure ethanol is a tasteless liquid with a strong and distinctive odor that produces a characteristic heat-like sensation when brought into contact with the tongue or mucous membranes. Ethanol adds a distinctive taste to drinks. 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.

Ethanol is a central nervous system depressant and has significant psychoactive effects in sublethal doses; for specifics, see Effects of alcohol on the body#Effects by dose. Based on its abilities to change the human consciousness, ethanol is considered a drug. "Alcohol Use" MedlinePlus Medical Encyclopedia, U.S. National Library of Medicine and National Institutes of Health. Retrieved on 2007-09-27 Death from ethyl alcohol consumption is possible when blood alcohol level reaches 0.4%. A blood level of 0.5% or more is commonly fatal. Levels of even less than 0.1% can cause intoxication, with unconsciousness often occurring at 0.3-0.4%.

In America, about half of the deaths in car accidents occur in alcohol-related crashes. There is no completely safe level of alcohol for driving, since the risk of a fatal car accident rises exponentially with the level of alcohol in the driver's blood. However, most drunk driving laws governing the acceptable levels in the blood while driving or operating heavy machinery set typical upper limits of between 0.05% or 0.08%.

Ethanol interacts in harmful ways with a number of other drugs, including barbiturates, benzodiazepines, narcotics, and phenothiazines

Metabolism Ethanol within the human body is converted into acetaldehyde by alcohol dehydrogenase and then into acetic acid by acetaldehyde dehydrogenase. The product of the first step of this breakdown, acetaldehyde, is more toxic than ethanol. Acetaldehyde is linked to most of the clinical effects of alcohol. It has been shown to increase the risk of contracting cirrhosis of the liver, multiple forms of cancer, and alcoholism.

Magnitude of effect 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 drug tolerance have a greater quantity of these enzymes, and metabolize ethanol more rapidly.

The amount of ethanol in the body is typically quantified 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 judgement. At higher dosages (BAC > 100 mg/dl), 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.

Frequent use of alcoholic beverages has also been shown to be a major contributing factor in cases of elevated blood levels of triglycerides.{{cite web|url=http://www.americanheart.org/presenter.jhtml?identifier=4778|title=Triglycerides|accessdate=2007-09-04|publisher=American Heart Association-->

See also

References Further reading

External links



 

Ethanol



 
Copyright © 2008 Hintcenter.com - All rights reserved.
Home | Terms of Use | Privacy Policy
All Trademarks belong to their repective owners. Many aspects of this page are used under
commercial commons license from Yahoo!