Methylester

A methylester, commonly called a methyl ester, is an organic compound in which a carboxylic acid has formed an ester with methanol, giving the general structure R-COO-CH3. It is the methyl ester of the corresponding carboxylic acid and represents the subset of esters where the alkyl group is a methyl group.

Methyl esters are typically prepared by Fischer esterification, combining a carboxylic acid with methanol in the presence of an acid catalyst and removing water to drive the equilibrium. They can also be prepared or interconverted by transesterification from other esters using methanol. In naming, the parent acid determines the name of the ester, e.g., methyl formate (HCOOCH3) from formic acid, and methyl acetate (CH3COOCH3) from acetic acid.

Common and notable examples include fatty acid methyl esters (FAMEs), such as methyl palmitate and methyl oleate, which are widely used in biodiesel and lipid analysis. Methyl esters also occur naturally in flavors and fragrances and serve as solvents or plasticizers in various industries. In analytical chemistry, methyl esters are frequently generated from fatty acids to form fatty acid methyl esters for gas chromatography analysis of lipid composition.

Properties and reactivity: methyl esters are typically polar, with solubility in organic solvents and varying volatility depending on chain length. They are relatively resistant to hydrolysis under neutral conditions but can be hydrolyzed back to the parent acid and methanol under acidic or basic conditions. Methanol, the alkyl donor, is toxic and handling requires appropriate safety measures.

In summary, methyl esters are esters with a methyl group from methanol, widely used in industry, analysis, and biology.