Glycerol Derivatives as Motifs for Green and Sustainable Chemistry

Abstract

The thesis entitled Glycerol Derivatives as Motifs for Green and Sustainable Chemistry is a step towards the practice of green and sustainable chemistry approach in producing industrially important chemicals. The choice of glycerol as a feed stock and its conversion via solvent free transformations with the help of suitable catalysts ensured hassle free workup, clean and significant yield of the products and scalability. In the present research work the glycerol was converted to Solketal with solid-acid catalysts, Hand#946;-Zeolite and Sulfated Zirconia at room temperature in yields ranging from 85-98% depending on the ratio of reactants and catalyst amount. This dehydrative ketalization of glycerol was found to be dependent on the affinity of active acid sites of the catalyst towards water and in that context Hand#946;-Zeolite performed better than Sulfated Zirconia. Moreover it showed excellent reusability without any particular post-treatment. It showed significant catalytic activity for solketal formation till 10 cycles in tandem. The mechanism we proposed amplifies the role of released water molecules bound to the Bronsted and Lewis acid sites of the catalysts, where we propose that the Bronsted sites have higher affinity towards H2O and do not release them without washing with solvents and re-activation at elevated temperatures. The produced solketal was converted to an ether with the substitution by n-Butyl bromide resulting in Butyl solketal in presence of KOH in equivalent amounts. This compound was thoroughly characterized using NMR, Mass, and elemental analysis. Ethers of solketal are known to be added in fuels to improve Carbon to Oxygen ratio. We employed this compound as a fuel additive to Motor diesel in various proportions and it showed enhancement in the fuel efficiency of about 14% in the CI engine test rig and about 20% in the conventional mini tractor fitted with 16 HP tractor model with a 709cc engine. This product has excellent commercial potential and eventually was patented during the course of the P