Theoretical and Kinetic Analysis of the Esterification of Undecylenic Acid with Glycerol

Abstract

The synthesis of undecylenic acid partial esters can be performed at mild temperature with a classical esterification reaction catalyzed by dodecylbenzene sulfonic acid (DBSA). A semi‐empirical molecular modeling on the different reaction intermediates indicates that DBSA can strongly decrease their heats of formation through hydrogen bonding. Diester formation seems to be thermodynamically favored with a selectivity for alpha, alpha, or alpha, beta forms that depend on the geometry of the catalyst‐intermediate configuration. Triesters are not favored but a high selectivity for monoesters requires a kinetic control. Experimental approach, considering different DBSA concentrations and temperature partially confirms the theoretical predictions but surfactant properties of DBSA and monoesters may induce nonpredicted geometries. Global apparent activation energies are calculated, corresponding to the formation and hydrolysis of mono and diesters. If water trapping allows the decrease of hydrolysis reaction constants, the presence of water and subsequent phase separation may explain differences between theoretical and experimental results and could help increasing monoester selectivity.

A fully bio‐based monomer derived from undecylenic acid, glycerol, and CO2 useful for the synthesis of polyhydroxyurethanes

“…The esterification reaction between glycerol and UA can produce mono‐, di‐, and triglycerides 24 . An excess of UA and a high temperature were used to favor the production of triglyceride product 25 . Also, the polymerization or oxidation of the terminal double bonds can occur as secondary reactions 26 .…”

“…24 An excess of UA and a high temperature were used to favor the production of triglyceride product. 25 Also, the polymerization or oxidation of the terminal double bonds can occur as secondary reactions. 26 Therefore, the reaction is carried out in the presence of hydroquinone to inhibit polymerization, and nitrogen atmosphere to avoid the oxidation reaction.…”