Synthesis of diethyl malonate catalyzed by chitosan sulfate

Diethyl malonate was synthesized by esterification with malonic acid and ethanol as reactants and chitosan sulfate as the heterogeneous catalyst.Through orthogonal designed experiments,the optimal reaction conditions were obtained as follows: amount of malonic acid,0.1 mol;mole ratio of ethanol to malonic acid,3.0 to 1.0;dosage of catalyst,2.0% of the total mass of the reactants;benzene used as water-stripping agent at dosage of 15 mL;reaction time under reflux boiling,2.0 h.Under these conditions,yield of diethyl malonate achieves higher than 97%.The results showed that chitosan sulfate has excellently catalytic activity and could be used repeatedly.