Exploring the Catalytic Potential of Metal Nanoparticles Stabilized in Alternative Solvents for Transfer Hydrogenation Reactions
Date
2024-02-28
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
ORCID
Type
Thesis
Degree Level
Masters
Abstract
Ionic liquids and deep eutectic solvents have emerged as promising alternatives to conventional solvents in catalytic processes as they possess low vapour pressure, high thermal stability, wide liquid temperature ranges, and tunable physicochemical properties. Moreover, palladium nanoparticles have garnered significant attention as versatile catalysts in hydrogenation reactions due to their unique properties and high catalytic activity. The utilization of nanoparticles in conjunction with ionic liquids and deep eutectic solvents has emerged as a promising strategy for enhancing hydrogenation processes. These composite systems offer unique advantages, including increased catalytic activity, improved stability in elevated temperature conditions, efficient mass transfer, and recyclability. Conventional direct hydrogenations in nanoparticle-ionic liquid composites often suffer from limitations such as low selectivity, mass transfer issues, tri-phasic catalysis, and the need for hazardous pressurized hydrogen gas. Room temperature transfer hydrogenation is a vital alternative catalytic sustainable process to direct hydrogenation for numerous organic transformations. This thesis explores the potential of using different alcohols, and ammonia borane as hydrogen donors for transfer hydrogenations using Pd nanoparticle catalysts in tetraalkylphosphonium halide ionic liquids, and urea-based deep eutectic solvents. The products of the catalytic reactions are analysed using 1H nuclear magnetic resonance. The characterization of the Pd nanoparticle catalysts in ionic liquids and deep eutectic solvents is performed using various techniques including transmission electron microscopy and X-ray absorption spectroscopy. The obtained results unequivocally showcase the remarkable catalytic activity and recyclability exhibited by the composite catalytic systems. Notably, these findings extend to diverse transfer hydrogenation reactions conducted at room temperature and reveal that the selection of hydrogen donor profoundly influences the reaction outcome, particularly in terms of product selectivity.
Description
Keywords
Ionic Liquids, Deep Eutectic Solvents, Transfer Hydrogenations, Alcohols, Ammonia Borane, Palladium nanoparticles
Citation
Degree
Master of Science (M.Sc.)
Department
Chemistry
Program
Chemistry