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Strong acids catalyze the reaction by donating a proton to the carbonyl group, thus making it a more potent electrophile. Bases catalyze the reaction by removing a proton from the alcohol, thus making it more nucleophilic. The reaction can also be accomplished with the help of enzymes, particularly lipases (one example is the lipase E.C.3.1.1.3 ...
Esterification is the general name for a chemical reaction in which two reactants (typically an alcohol and an acid) form an ester as the reaction product. Esters are common in organic chemistry and biological materials, and often have a pleasant characteristic, fruity odor. This leads to their extensive use in the fragrance and flavor industry.
An example of an ester formation is the substitution reaction between a carboxylic acid (R−C(=O)−OH) and an alcohol (R'OH), forming an ester (R−C(=O)−O−R'), where R and R′ are organyl groups, or H in the case of esters of formic acid.
The most commonly used alcohol is methanol, producing fatty acid methyl esters (FAME). When ethanol is used fatty acid ethyl esters (FAEE) are created. Other alcohols used for the production of biodiesel include butanol and isopropanol. Fatty acid ethyl esters are biomarkers for the consumption of ethanol (alcoholic beverages). [1] [2] [3]
The reaction usually requires a catalyst, such as concentrated sulfuric acid: R−OH + R'−CO 2 H → R'−CO 2 R + H 2 O. Other types of ester are prepared in a similar manner−for example, tosyl (tosylate) esters are made by reaction of the alcohol with 4-toluenesulfonyl chloride in pyridine.
Most fatty alcohols in nature are found as waxes, which are esters of fatty acids and fatty alcohols. [1] They are produced by bacteria, plants and animals for purposes of buoyancy, as source of metabolic water and energy, biosonar lenses (marine mammals) and for thermal insulation in the form of waxes (in plants and insects). [3]
Alcohol oxidation is a collection of oxidation reactions in organic chemistry that convert alcohols to aldehydes, ketones, carboxylic acids, and esters. The reaction mainly applies to primary and secondary alcohols. Secondary alcohols form ketones, while primary alcohols form aldehydes or carboxylic acids. [1] A variety of oxidants can be used.
[4] [6] Alcohol dehydrogenase and aldehyde dehydrogenase are present at their highest concentrations (in liver mitochondria). [98] [107] But these enzymes are widely expressed throughout the body, such as in the stomach and small intestine. [2] Some alcohol undergoes a first pass of metabolism in these areas, before it ever enters the ...