Process for the preparation of acids

摘要

A carboxylic acid of formula RCO2H where R is a C1 to C10 aliphatic hydrocarbyl group is prepared by heating under substantially anhydrous conditions an ester of formic acid of formula HCO2R where R is as defined above in the presence of carbon monoxide and an effective amount of a catalyst system comprising a Group VIII metal, a halide and a compound containing a quaternary Group V atom. The quaternary Group V atom can be formed in situ by adding a compound containing a trivalent nitrogen, phosphorus or arsenic atom quaternizable under the reaction conditions and a quaternizing agent. Acetic acid is prepared by heating methyl formate in the presence of a catalyst system containing a rhodium compound, an iodide and a quaternary nitrogen-containing heterocyclic base.