Electrosynthesis of tetrabenzylthiuram disulfide via flow reactors

Abstract

• Advanced flow electrosynthesis method of TBzTD is developed. • Main factors influenced the electrosynthesis reaction are carefully discussed. • The scaling-up of flow reactor via increasing electrode area is exhibited. • Circulation of aqueous solution is accomplished for high atomic economy. Tetrabenzylthiuram disulfide (TBzTD) is an environmentally friendly vulcanization accelerator, which has attracted much attention in recent years. In contrast to traditional synthesis technologies, which create stoichiometric sodium sulfate or sodium chloride waste salts, we carefully studied an electrosynthesis method of TBzTD based on flow reactors, which prevented the generation of salt. Two reactors with different electrode areas were used to implement the electrochemical oxidative coupling reaction of sodium dibenzyl dithiocarbamates, and effects of potential, current, electrode material, electrode distance, flow rate, concentration, and temperature on the yield and space time yield of TBzTD were carefully investigated. Almost 100% Faraday efficiency of the reaction was obtained at relatively optimized reaction condition and the highest yield of TBzTD reached 86%. Although the yield of TBzTD did not reach 100% in the electrosynthesis reaction, the circulation of aqueous phase demonstrated by a membrane separator assisted flow reaction system helped to accomplish fully conversion of initial amine and carbon disulfide and atomic economic synthesis of TBzTD.