Study on conversion of glycerol into value added products

Abstract

The limited nature of fossil fuel reserves, detrimental environmental issues and climate change caused by their usage ascended the need for renewable energy-based fuel in recent years. Developing an alternative renewable resource-based fuel not only meets the needs of future fuels but also improves the ecological system of the earth. These fuels are named as biofuels and the most common one is biodiesel. It is a prominent fuel and a good replacement for petroleum diesel, mainly due to its renewable, non-toxic, biodegradable and environment friendly nature. Biodiesel, a diesel fuel substitute, consists of long-chain fatty acids esters that can be derived via reaction between triglyceride (plants and animal s oils/fats, tallow and waste cooking oil) with an alcohol to form esters and glycerol in the presence of a suitable catalyst. This process is commonly termed as transesterification process and the chief by-product of this process is glycerol. newlineGlycerol or glycerine or propane-1,2,3-triol, is a polyol compound. It is a trihydroxy sugar alcohol with three carbon atoms and three hydroxyl groups. These hydroxyl groups make glycerol versatile and responsible for its hygroscopic nature. It is a colourless, odourless, viscous, sweet-tasting liquid and non-toxic. About 1 kg of crude glycerol is generated with every 10 kg of biodiesel produced during biodiesel production. Thus, a substantial increase in the production of biodiesel consequently leads to the excess generation of glycerol. Every year, a billion litres of glycerol is produced and is only treated as a waste stream that raises environmental problems. Hence, the transformation of glycerol into valuable chemical intermediates is necessary due to the availability of glycerol as a glut. Also, the utilisation of wastes or by-products enhances their sustainability. newlineTherefore, a lot of research has been done for the conversion of glycerol. It has wide range of applications such as in co