Executive Summary : | Interface formed between two immiscible liquids was found to be an efficient reaction system for catalysis owing to its potential to control the selectivity of chemical reactions. This can be ascribed to the unique structural, chemical, and electronic properties of the interface as compared to the bulk. In spite of numerous experimental and computational studies over the years, our understanding of the interfacial structure and properties of various biphasic systems is still elusive. In this regard, we will be studying the properties of some of the interesting biphasic liquid mediums, focusing on their interfacial structure and their role in determining the kinetics and selectivity of chemical reactions that have application in biofuel production from cellulose. In spite of its great potential to be used as a renewable energy source, cellulose-based biofuel production is severely hampered by its poor yield, especially in the aqueous medium. Earlier studies indicated that employing a biphasic medium comprising of an aqueous and non-aqueous medium could improve the yield and selectivity (for biofuel precursor molecules) of this reaction substantially. However, the mechanism, kinetics, and for selectivity in the conversion of cellulose to biofuel precursor molecules such as HMF in biphasic mediums are not well explored. In this project, we will be scrutinizing these aspects in different biphasic mediums such as aqueous-organic and aqueous-super critical CO₂ by employing classical and ab initio molecular dynamics simulations in conjunction with enhanced sampling approaches. The effect of aqueous and non-aqueous components of the biphasic systems and their interfacial structure on the mechanism, kinetics, and the experimentally observed selectivity will be analyzed here. Microkinetic studies to identify the maximally contributing reaction pathways from various possible reaction routes that result in biofuels from cellulose in different biphasic systems will also be carried out. Moreover, a comparison of the results obtained for the biphasic medium with that of the aqueous medium will be performed. The results of this study will help us to devise a strategy to modulate the interfacial properties by introducing suitable additives to improve the yield and selectivity of the cellulose to biofuel conversion reactions. This in turn will help us to design a suitable solvent medium that can work in less severe reaction conditions. The feasibility of a “green reaction medium” such as the aqueous-supercritical CO₂ biphasic medium, that can reduce the cost of cellulose to HMF conversion as well as reduce greenhouse gas like CO₂ will also be explored. Moreover, this work will also give a fundamental understanding of the effect of solvents, interface, and reaction conditions on various chemical reactions in carbohydrate chemistry. The outcome of this work is expected to have a good impact on the ongoing efforts in fuel production from biomass. |