Studies on the Synthesis Characterization and Catalytic Activity of Pd Sn Bimetallic Nanoparticles

Abstract

The thesis entitled Studies on the Synthesis, Characterization and Catalytic Activity newlineof Pd-Sn Bimetallic Nanoparticles is primarily an effort towards the understanding newlineof bimetallic nanoparticles (here after BNPs) as catalysts for oxidation and reduction newlinereactions. Gratifyingly, these BNPs showed specific catalytic behaviour only in water newlineas the media, thereby adding to their relevance in green chemistry. newlineChapter 1 describes a brief introduction and literature survey on the developments of newlineBNPs as catalysts. The focus has been mainly on late transition metal systems; their newlinemethods of synthesis, and catalytic application.Chapter 2 describes the synthesis of Pd-Sn BNPs as well as Pd nanoparticles newline(hereafter NPs) by wet chemical method using polyvinylpyrrolidone (PVP) as newlinestabilizer and NaBH4 as reducing agent. The catalysts were characterized by a battery newlineof techniques that includes UV-Vis, FTIR, FESEM, EDAX, HRTEM, XPS and ICPOES.In chapter 3 we demonstrated Pd-Sn BNPs catalyzed aerobic oxidation of benzyl alcohols (here after BnOH) to the corresponding carbonyl derivatives. The reaction was conducted in water as the solvent and without using base. Initial rate studies revealed the higher efficiency of bimetallic Pd-Sn NPs over Pd-NPs. The ease of preparation of the catalyst, its high self-life, low loading, high TOF values and the ability to withstand multiple cycles are the most noteworthy features. Preliminary kinetic studies are indicative of a and#946;-hydride elimination mechanism.Chapter 4 describes the catalytic efficiency of Pd-Sn nanocatalysts for the oxidative homocoupling of primary amines and tandem coupling between amine and alcohol in water. The catalytic system promotes two different reactions in water, thereby adding to its green relevance. Another novel feature of the catalyst is that in presence of oxygen, both the oxidative coupling and tandem coupling stops at the imine stage. Mechanistic studies showed a positive isotope effect indicating N-H bond dissociation in the rate determining step.