Ethanol

Ethanol is made up of two carbon atoms forming a double bond with each other and four hydrogens attaching to the carbons (2h-C=C-2h). Ethanol is a very flammable, colorless liquid. Ethanol is an alcohol based chemical. Ethanol is the main component of a psychoactive drug and is one of the oldest type of recreational drugs known. Its most common use is in alcohol or 'spirits'. Ethanol is a grain alcohol that is used as fuel, it is made by fermenting crops. Some good examples are corn, wheat, sugar cane, and sugar beets.

To significantly expand its market share on a large scale, ethanol must become cheaper. For that to happen, inexpensive and plentiful feedstocks must be found outside the Midwest corn belt. A significant breakthrough is the conversation of biomass into cellulosic ethanol, which could provide nationwide ethanol production options that today are limited to corn producing states. The U. S. Department of Energy, Secretary Samuel Boden, has this to say about accelerating the research of cellulosic ethanol: > //We need to develop and deploy the next generation of ethanol - ethanol and other products made from biomass products that are outside the food chain. In my view, this means cellulosic fuels made from agricultural waste products and crops like switchgrass, which can be grown and regenerated on less desirable lands.// Cellulosic ethanol is an environmentally friendly and renewable transportation fuel produced from a wide array of feedstocks, including non-food plant materials such as agricultural wastes, dedicated energy crops such as switchgrass, sugarcane bagasse, and wood products. Moreover, unlike corn ethanol, cellulosic biofuel does not require fertilizers, pesticides, energy, and water to grow. Cellulosic ethanol and conventional, grain-based ethanol have identical molecules, but they differ in that conventional fuel ethanol is derived from only a small fraction of biomass feedstock, the edible parts of corn or other feed grains, while cellulose ethanol is made from the non-food portion of renewable feedstocks such as cereal straws and corn stover (leaves and stems) or **__dedicated energy crops__**. While the refining process for cellulosic ethanol is more complex than that of corn-based ethanol, cellulosic ethanol yields a greater net energy benefit and results in much lower greenhouse gas emissions.



Is a central nervous system depressant. It has been shown to increase risks of liver damages as well as certain cancers. 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.

** Chemical formula ** Ethanol is a 2-carbon alcohol with the molecular formula CH 3 CH 2 OH. Its empirical formula is C 2 H 6  O. An alternative notation is CH 3 –CH 2 –OH, which indicates that the carbon of a methyl group (CH 3 - ) is attached to the carbon of a methylene group (–CH 2 - ), which is attached to the oxygen of a hydroxyl group (–OH). It is a constitutional isomer of dimethyl ether. Ethanol is often abbreviated as **EtOH**, using the common organic chemistry notation of representing the ethyl group (C 2 H 5 ) with **Et**.

Reactions Ethanol is classified as a primary alcohol, meaning that the carbon 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 acids to produce ethyl esters and water: RCOOH + HOCH2CH3 → RCOOCH 2 CH 3 + 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 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 a widely used diuretic.

Dehydration
Strong acid desiccants cause the dehydration of ethanol to form diethyl ether and other byproducts. If the dehydration temperature exceeds around 160 °C, ethylene will be the main product. Millions of kilograms of diethyl ether are produced annually using sulfuric acid catalyst: 2 CH3CH2OH → CH3CH2OCH2CH3 + H2O (on 120 °C)

Combustion
Complete combustion of ethanol forms carbon dioxide and water vapor: C2H5OH (l) + 3 O2 (g) → 2 CO2 (g) + 3 H2O (g); (ΔHc = −1371 kJ/mol [|[] ) 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 : 2 CH3CH2OH + 2 Na → 2 CH3CH2ONa + H2 or a very strong base such as sodium hydride : CH3CH2OH + NaH → CH3CH2ONa + H2 The acidity 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 exist in an equilbrium 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 S N 2 reaction : CH3CH2OH + HCl → CH3CH2Cl + H2O These reactions require a catalyst such as zinc chloride. HBr requires refluxing with a sulfuric acid catalyst. Ethyl halides can, in principle, also be produced by treating ethanol with more specialized halogenating agents, such as thionyl chloride 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 called chloral : 4 Cl2 + CH3CH2OH → CCl3CHO + 5 HCl

Oxidation
Ethanol can be oxidized to acetaldehyde and further oxidized to acetic acid, 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 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.