Kinetics and the fluidity of the stearic acid esters with different carbon backbones

Abstract

In this work, stearic acid esters were prepared using [HPY][HSO4] ionic liquids as catalysts and different kinds of alcohols and stearic acid as reactants in a self-designed reactor. Catalytic esterification, kinetics analysis and low temperature fluidity of the esters were studied. Through single-factor experiment, the optimal reaction conditions were determined for methyl stearate, ethyl ester, propyl ester, butyl ester, and amyl ester. The conversion rates under the optimized conditions were all above 97%. The kinetics of the reaction process of all five esters was analyzed by the integral method, and the activation energy, pre-exponential factor and kinetic model were obtained for the five esters. Finally, the low temperature fluidity of all esters was tested and the best value was observed for amyl alcohol. Therefore, these esters would be useful additives for reducing the condensation and cold filter plugging points of biodiesel, thus improving the cold flow properties of biodiesel.

Keywords

• catalytic esterification
• single-factor experiment kinetics
• low-temperature fluidity study