Green Process Development for Production of 1,2 Propane-diol from Hydrogenation of Glycerol

Abstract

In current scenario, in general researchers are looking for renewable resources for production of commercially important products. Biodiesel production, from various renewable resources, by conventional esterification /or trans-esterification reaction, produces glycerol as one of the major co-product. Thus glycerol from biodiesel is renewable resource. Due to presence of three –OH groups in glycerol its becomes higly functional molecule and various commercially important products can be produced like 1,2 Propane-diol. Production of 1,2 Propane-diol through glycerol is an attractive route to use renewable resources. This work presents review of various routes for glycerol to 1,2 Propane-diol reaction using heterogeneous catalyst. Based on literature survey, copper alumina phosphate (CAP) shows highest possible conversion with very good selectivity for 1,2 Propane-diol. However such reactions were carried at very high temperature and pressure, i.e. more than 220°C and more than 52 bar(g) pressure. CAP catalyst was synthesized with different synthesis method and different promoters to enhance conversion and selectivity. Liquid phase reactions were carried out in high pressure reactor in presence of synthesized heterogeneous catalysts. Reaction mixture was analyzed using gas chromatography techniques. Objective to carry out this work was to reduce the severity of the operation with good conversion and selectivity. But results are not encouraging. Copper alumina phosphate (with KOH as promoter) shows highest possible conversion, 5.5% at 30 bar(g) pressure, 180°C temperature and 5 hours reaction time. Under similar conditions NaOH promoted CAP shows 4.2% conversion compared to 51% in the literature at higher temperature and pressure conditions. Two major reasons for poor performance can be contributed to improper preparation of catalyst and less severe conditions of operation can be considered.