Preparation And Catalytic Properties Of Carbon Nanotubes Supported Platinum And Ruthenium Catalysts In The Hydrogenation Of Carbonyl Compounds

Alcohols are very important intermediate for the synthesis of many organic products or pharmaceuticals. Many of the alcohols derived from the hydrogenation of the carbonyl-containing compounds. In recent years, homogeneous catalytic hydrogenation of carbonyl compounds has been developing rapidly, whereas, heterogeneous hydrogenation development is slow. In relation to the homogenous hydrogenantion, heterogenous hydrogenantion bears many of the advantages such as easier preparation steps of the catalyst, moderater reaction conditions, fewer separation opration of the catalyst, simpler reaction procedures, etc. In this thesis, the carbon nanotubes supported transition metal catalysts were synthesized and been used as efficient catalysts for the hydrogenation reaction of carbonyl compounds.The thesis consists of three chapters as follows:Chapter 1. ReviewsThe following three points were reviewed including(1) Green chemistry. The history, the definition, the principles, the research methods, especially the contents of green chemistry were introduced.(2) Carbon nanotubes(CNTs). The property, the production, the development, as well as the application of carbon nanotubes were reviewed. The research status of carbon nanotubes in catalysis was mainly introduced.(3) Hydrogenation of carbonyl compounds. The catalytic hydrogenation of aldehyde and ketone was concluded. The research on the catalytic hydrogenation of ketone was well introduced.Chapter 2. Catalytic hydrogenantion of aldehydes with the catalysis of carbon nanotubes supported Pt catalyst(Rt/CNTs)Pt/CNTs was prepared through impregnating and characterized by XPS, XRD, BET, TEM and FTIR methods. The result showed that all the Pt nanoparticles(NPs) are dispersed uniformly on the carbon nanotubes. The tubular structure was well retained during the pretreatment and the loading of Pt NPs on CNTs. The catalytic property of the Pt/CNTs was tested in the hydrogenation of p-methoxybenzaldehyde with water as the reaction medium. The influence of the amounts of Pt/CNTs, the pressures, the solvent, the reaction time as well as the temperature was optimized. The scopes of the substrates were also screened. It was found that the catalyst can be successfully applied to many hydrogenation systems to convert several carbonyl compounds to the corresponding alcohols. The catalyst can be reused at least four times in the hydrogenation of p-methoxybenzaldehyde without obviously loss of activity.Chapter 3. Catalytic hydrogenation of acetophenone with the catalysis of carbon nanotubes supported Ru catalyst(Ru/CNTs)CNTs was simplely treated, and the carbon nanotubes supported Ru catalyst of Ru/CNTs was prepared through impregnating method and characterized by XPS, XRD, BET, TEM and FTIR methods. The result showed that the catalyst has stable structure and the active Ru NPs dispersed uniformly on the CNTs. The application of(1S, 2S)-DPEN and L-proline as modifier for hydrogenation of ketone in water medium has been researched, respectively. The influence of the temperature, the pressure, the solvent, the kind and the concentration of the base as well as the the amounts of modifier was optimized. It was found that the catalysts can be successfully applied to many hydrogenation systems. High substrate conversions as well as product selectivities were obtained in these reactions. The catalyst can be reused four times in the hydrogenation of acetophenone without palpable loss of activity.