A process for making monomenthyl esters of dicarboxylic acids is
disclosed. Menthol reacts with a saturated, cyclic anhydride in the
presence of a base catalyst under conditions effective to produce a
mixture of mono- and bis-menthyl esters in which the molar ratio of mono-
to bis-menthyl esters is enhanced compared with the ratio of esters
produced in a similar uncatalyzed process.