A process the preparation of a dithiocarboxylic esters comprises reacting a carboxylic acid compound of formula R1(COOH)m, a compound of formula R2AH and phosphorus pentasulfide to produce a compound of structure I. An alternate process comprises reacting a compound of formula R3(COAH)m and a compound of structure II in the presence of a clay catalyst; and treating products of the reaction with a thiating agent to produce a compound of structure III, a compound of structure IV, or a combination of compounds of structure III and structure IV.