Sulfonic acid functionalized poly(ethylene glycol dimethacrylate-1-vinyl-1,2,4-triazole) as a high-performance solid acid catalyst for the esterification of lactic acid with methanol

J Colloid Interface Sci. 2012 Feb 1;367(1):394-7. doi: 10.1016/j.jcis.2011.10.039. Epub 2011 Oct 23.

Abstract

Sulfonic acid functionalized poly(ethylene glycol dimethacrylate-1-vinyl-1,2,4-triazole), poly(EGDMA-VTAZ-SO(3)H), is evaluated in the esterification of lactic acid with methanol. From nitrogen physisorption data, high surface area (220 m(2)/g) and type IV isotherm are obtained. Conversion measurements indicate a stronger interaction of poly(EGDMA-VTAZ-20%SO(3)H) with water molecules than that occurring in poly(EGDMA-VTAZ-10%SO(3)H). Hence, the higher catalytic activity of poly(EGDMA-VTAZ-10%SO(3)H) is related to the more hydrophobic microenvironment of -SO(3)H sites, which reduces the acid site deactivation associated with adsorption of water generated during the reaction. Moreover, apparent activation energy is found to be 48.02 kJ mol(-1), which can be comparable with the literature values.