Kinetics of mixed succinic acid/acetic acid esterification with Amberlyst 70 ion exchange resin as catalyst

Liquid phase esterification of succinic acid, acetic acid and succinic/acetic acid mixtures with ethanol was studied using Amberlyst 70 strong cation exchange resin as catalyst. Batch isothermal reactions were performed at different ethanol:acid molar ratios (1:1–27:1), temperatures (343–393 K) and catalyst loadings (1.0–9.3 wt% of solution). Esterification kinetics is described using both pseudo-homogeneous mole fraction and NRTL-based activity based models that take ethanol dehydration to diethyl ether into account. The models accurately predict the esterification of individual acids, and a simple additive combination of independent kinetic models provides a good description of mixed acid esterification. The kinetic models can be used in simulation of reactive distillation processes for mixed acid esterification.

► This paper describes the kinetics of succinic acid and acetic acid esterification with ethanol over Amberlyst 70 ion exchange resin catalyst.
► Esterification rates of the individual acids are presented along with ethanol dehydration to diethyl ether.
► The kinetics of mixed acid esterification can be characterized by a simple additive model of the individual acid esterification rates, signifying that the acids do not compete for active sites and thus do not inhibit each others’ rate.
► Amberlyst 70 is an effective catalyst for the reaction.