Selective synthesis of perfumery grade cyclohexyl esters from cyclohexene and carboxylic acids over ion exchange resins: an example of 100% atom economy
Summary Esterification is important in the perfumery and flavour chemical industry, wherein, both homogeneous and heterogeneous cata- lysts have been widely used. The use of solid acid catalysts can be effective from the view of activity, selectivity, reusability and economy in the manufacture of perfumery esters. This paper delineates a 100% atom economical process for the preparation of cyclohexyl esters from carboxylic acids and cyclohexene over ion exchange resin catalysts where all the reactant atoms are utilised without any by-product formation. The preparation of perfumery esters such as cyclohexylphenyl acetate, cyclohexyl acetate, cyclohexyl anthranilate, cyclohexyl benzoate, cyclohexyl butyr- ate, cyclohexyl iso-butyrate, cyclohexyl heptanoate and cyclo- hexyl propionate is covered. A complete theoretical and experi- mental analysis is presented for the model studies with phenylacetic acid and cyclohexene.