BF3·Methanol

• One of the most convenient reagents for fatty acid derivatization
• Provides a convenient methanol-catalyst system; when used in excess (with heating), quickly and quantitativly converts carboxylic acids to their methyl esters
• Used to prepare methyl esters directly from a variety of esters including glycerides
• Most suitable for derivatizing higher boiling carboxylic acids
• Most protocols require separation of the methyl ester from the reaction mixture by some form of extraction, followed by evaporation of the solvent
• Special techniques are required to obtain reproducible results from fatty acids below C₈
• BF₃ is a relatively strong Lewis acid—compounds that undergo reactions or rearrangements under acidic conditions should be derivatized with caution using this reagent

BF₃-Methanol is one of the most convenient methods for the derivatization of fatty acids. Classical esterification chemistry calls for the reaction of a carboxylic acid with an alcohol in the presence of an acid catalyst. BF₃-Methanol provides a convenient methanol-catalyst system which, when used in excess with heating, quickly and quantitatively converts carboxylic acids to their methyl esters. Similarly, this combination of methanol and strong acid can be used to prepare methyl esters directly from a variety of esters, including glycerides. As most protocols for preparation of methyl esters with BF₃-Methanol require separation of the methyl ester from the reaction mixture by some form of extraction followed by evaporation of the solvent, this reagent is most suitable for derivatizing higher boiling carboxylic acids. Special techniques are required to obtain reproducible results from fatty acids below C₈. BF₃ is a relatively strong Lewis acid; therefore, compounds that undergo reactions or rearrangements under acidic conditions should be derivatized with caution when using this reagent.