Ester

In organic chemistry and biochemistry, esters are organic compounds where an organic group (symbolised by R' in this article) replaces a hydrogen atom (or more than one) in an oxygen acid. An oxygen acid is an acid whose molecule has an - group from which the hydrogen (H) can dissociate as an H+ ion.

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Esters are named similar to salts; although they don't really have cations and anions, the terminology follows the same pattern: a more electropositive part followed by a more electronegative part.

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The most common esters are the carboxylate esters, where the acid in question is a carboxylic acid. For example, if the acid is acetic acid, the ester is called an acetate.

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Esters may also be formed with inorganic acids; for example, dimethyl sulfate is an ester, and sometimes called "sulfuric acid, dimethyl ester".

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An ester can be thought of as a product of a condensation reaction of an acid (usually an organic acid) and an alcohol (or phenol compound), although there are other ways to form esters. Condensation is a type of chemical reaction in which two molecules with -OH groups are joined with eliminating a water molecule from their -OH groups. A condensation reaction to form an ester is called esterification. Esterification can be catalysed by the presence of H+ ions. Sulfuric acid is often used as a catalyst for this reaction. The name ester is derived from the German Essig-Aether, an old name for acetic acid ethyl ester (ethyl acetate).

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This is the general displayed formula of an ester of a carboxylic acid:

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Organic chemistry: Organic chemistry is the scientific study of the structure, properties, composition, reactions, and synthesis of organic compounds that by definition contain carbon. It is a specific discipline within the subject of chemistry. Organic compounds are molecules composed of carbon and hydrogen, and ma...

Biochemistry: Biochemistry is the chemistry of life, a bridge between biology and chemistry that studies how complex chemical reactions give rise to life. It is a hybrid branch of chemistry which specialises in the chemical processes in living organisms. This article only discusses terrestrial biochemistry (carbo...

Organic compound: An organic compound is any member of a large class of chemical compounds whose molecules contain carbon, with exception of carbides, carbonates, carbon oxides and gases containing carbon. The study of organic compounds is termed organic chemistry. Many of these compounds, such as proteins, fats, and...