Synthesis Of Cellulose-supported Triphenylphosphine And Its Application In Organic Reactions

Cellulose is the most abundant biopolymer in nature. It is an environmentalfriendly renewable resource. Cellulose-supported catalysts have been widely used inorganic reactions, such as oxidation, reduction, coupling and one-pot reactions etc.The exploitation of catalysts using cellulose as raw materials entirely meets therequirement of green chemistry and sustainable development strategy due to its cheapmaterial, easy separation from products and recycling.In this thesis, cellulose-supported triphenylphosphine was synthesized throughthe reaction of cellulose tosylate and4-Hydroxyphenyldiphenylphosphine, thencoordinated with palladium acetate to prepare cellulose-Pd complex. Its catalyticactivity on Suzuki coupling reaction was evaluated. During the process, theinfluencing factors of solvent, base, amount of catalyst, molar ratio of reactant wereinvestigated. The optimum conditions were as follows: ethanol as solvent, K2CO3,0.8mol%catalyst at80°C. Under the optimized conditions, various substrates wereexpanded and results indicated that the catalyst had high catalytic activity (yield>85%) except arylboronic acids with strong electron-withdrawing and heterocycleboronic acids. Recycling use of catalyst results indicated that catalyst had goodperformance in the previous2cycles (95%,94%) but the yield significantly decreased(62%) in the3rdreaction.We tried the catalytic performance of cellulose-supported triphenylphosphine forthe Wittig reaction. But the yield is very low (<20%). Subsequently, we studied theinfluential factors of Wittig reaction and carried out the corresponding controlledexperiment. Maybe low triphenylphosphine loading resulted in the low catalyticefficiency.