Synthesis of PEG-monooleate using cesium heteropoly acid as heterogeneous catalyst

Abstract

Esterification of oleic acid with polyethylene glycol 600 (PEG-600) to produce polyethylene glycol monooleate (PEG-monooleate) has been studied in the presence of heterogeneous acid catalysts; cesium heteropoly acid (Cs HPA). The results were compared with current industrially used homogeneous acid catalyst; p-toluene sulphonic acid (p-TSA). The reaction was conducted under flow of nitrogen with vigorous stirring at 130 °C and the reaction was monitored at 1, 3, 7 and 24 hours. The results showed Cs HPAs exhibit 100% selectivity of PEG-monooleate from the first hour until 24 hours of the reaction time. Contrary to p-TSA catalyst, the formation of side product; PEG-dioleate was observed since the beginning of the reaction. Chemical and physical properties of catalysts were characterized using fourier transmittance infra-red (FTIR) and X-ray diffraction (XRD).