GLYCEROL DEGRADATION IN THE ABSENCE OF EXTERNAL HYDROGEN GAS BY USING WASTE EGGSHELL AS HETEROGENEOUS CATALYST

The demand of biodiesel production nowadays is increasing every day. However, the booming of biodiesel demand resulted in the increase of glycerol production as a major by-product. Although glycerol could serve in various industries, the demand and usage are still limited. Therefore, an alternative method was proposed in this research in order to convert glycerol into more value-added chemicals such as methanol (MeOH), propanol (1-PrOH), and 1,2-propanediol (1,2-PDO) through a new low cost and simple approach which is the reflux technique in the absence of external hydrogen gas. Due to the concern of global food waste issues, calcium oxide (CaO) catalyst derived from waste eggshells is utilized as a possible heterogeneous catalyst. This preliminary research studied the influence of reaction temperature and reaction time whereas catalyst weight and glycerol concentration were fixed as independent variables. Overall, the three chemicals were successfully synthesized with different optimum conditions. The formation of 1,2-PDO is more preferred at lower temperature (130 °C and 5 hours) with glycerol conversion and selectivity of 53.70% and 64.76%, respectively. However, the formation of MeOH and 1-PrOH are preferred at higher temperature. The formation of 1-PrOH (170 °C and 5 hours) resulted in glycerol conversion and selectivity of 81.64% and 70.85%, respectively. Meanwhile, the best condition in the formation of MeOH is at 190 °C and 7 hours reaction time with glycerol conversion and selectivity of 65.8 % and 46.44%, respectively.