Novel esterification reaction from biomass product by coupled acetate membrane and catalysts for ethyl lactate separation

Abstract

This study presents the effect of combined membrane separation and heterogeneous catalysts for the production of ethyl lactate solvent. The enhanced process is a flat sheet cellulose acetate membrane and cation-exchange resin catalysts. A methodology based on catalyst and acetate membrane impregnation in the presence of a sweep gas at low pressure with the aim of obtaining a higher yield of the ester product have been developed. The esterification reaction was carried out at the temperature of 60 °C. The ester product gave a percentage yield of up to 75%. The ion chromatogram of the ester product obtained in the catalyst and membrane impregnation was compared with the esterification product of the batch esterification reaction. The gas chromatograph NIST library spectra of the ester product indicated the structure of ethyl lactate (45) on the mass spectra which was in accordance with the commercial ethyl lactate. Products obtained on dowex 50W8x and amberlyst 36 resin catalysts were found to elute faster at 1.503 and 1.527 min respectively in contrast to those using amberlyst 15 and amberlyst 16. In all, the percentage yield of the ethyl lactate can be improved using cellulose acetate membrane. Amberlyst 36 and dowex 50W8x cation-exchange resins were revealed as the most effective catalysts for the esterification process involving lactic and ethanol to produce ethyl lactate in contrast to other cation-exchange resins that were used in the study. The results further confirms effectiveness of cellulose acetate membrane in the selective removal of the water from the esterification product.