In chemistry, the alkoxy group is an alkyl group which is singularly bonded to oxygen; thus R−O. Denoted usually with apostrophe('). The range of alkoxy groups is vast, the simplest being methoxy (CH3O−). An ethoxy group (CH3CH2O−) is found in the organic compound ethyl phenyl ether (C6H5OCH2CH3, also known as ethoxybenzene).
Related to alkoxy groups are aryloxy groups, which have an aryl group singularly bonded to oxygen such as the phenoxy group (C6H5O−).
In organic chemistry, a methoxy group is the functional group consisting of a methyl group bound to oxygen. This alkoxy group has the formula R−O−CH3.
On a benzene ring, the Hammett equation classifies a methoxy substituent at the para position as an electron-donating group, but as an electron-withdrawing group if at the meta position. At the ortho position, steric effects are likely to cause a significant alteration in the Hammett equation prediction, which otherwise follows the same trend as that of the para position.
Transesterification is the process of exchanging the organic functional group R″ of an ester with the organic group R' of an alcohol. These reactions are often catalyzed by the addition of an acid or base catalyst. 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).
If the alcohol produced by the reaction can be separated from the reactants by distillation this will drive the equilibrium toward the products. This means that esters with larger alkoxy groups can be made from methyl or ethyl esters in high purity by heating the mixture of ester, acid/base, and large alcohol.
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