Disclosed is a process for the production of esters. In particular, the process includes contacting an olefin or an ether with carbon monoxide and an acid composition comprising BF₃.2CH₃OH to from a product composition, adding an alcohol to the product composition, and separating the BF₃.2CH₃OH from the ester. The separated BF₃.2CH₃OH may then be recycled to the reaction unit.