Solvent-free direct esterification of acrylic acid with 2-ethylhexyl alcohol using simple Zn(II) catalysts
Massimo Melchiorre, RobertoEsposito, VincenzoRusso, MartinoDi Serio, MariaElena Cucciolito, FrancescoRuffo.
Direct esterification of acrylic acid with 2-ethylhexyl alcohol was investigated using low toxic and cheap Zn(II) salts as catalysts. An initial screening using Zn(ClO4)2, ZnCl2, Zn(OAc)2 and ZnO disclosed that the most effective was the perchlorate, which was used for the subsequent refining of the study. In optimized conditions (0.5 % mol of polymerization inhibitor, 0.1 % mol of catalyst, 170 °C, 4 h) the product was obtained in 99 % yield. A kinetic model was proposed to quantify the contribution of each chemical reaction of the network, allowing a quantitative comparison of the effect of the inhibitors on the acrylic acid esterification side-reactions.