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Chitosan is a polysaccharide nature, so far only found in trona , its structure contains glucosamine unit and acetyl glucosamine unit , for some metal ions , particularly transition metal ions have a good chelating action , and its wide range of sources , with a very good biodegradability . Nature chitosan , lysozyme and microbial completely biodegradable and is a renewable resource and environmentally friendly materials . The catalytic hydrogenation has wide application in organic synthesis , especially in the synthesis of chemical products occupy an important position . At present, the polymer-metal complexes as a catalyst for the catalytic hydrogenation reaction due to the mild reaction conditions , do not pollute the environment and other advantages has become a focus for researchers . Crown ether compounds has a unique molecular structure and selective coordination ability , host - guest complex with many metal ions to form selective use of the synergies of chitosan crown ethers were prepared modified chitosan crown ethers . This article provides an overview of the structure and physical and chemical properties of chitosan , chitosan metal complex catalyst research progress ; briefly the crown ether polymer metal complexes of crown ethers in catalysis ; overview of palladium Research Progress based catalysts in catalytic hydrogenation . In this thesis focuses on the preparation and characterization of the three modified chitosan load palladium chloride catalyst , and also discusses the three catalyst on the catalytic properties of p-nitroaniline . Main contents are as follows: preparation of chitosan graft benzo 18 - crown-6 , crosslinked chitosan microspheres , dibenzo- 18 - crown-6 crosslinked chitosan and load palladium chloride system became palladium heterogeneous catalyst, and respectively on the three catalyst with X-ray photoelectron spectroscopy (XPS) Characterization final respectively three catalysts , catalytic p-nitroaniline generated phenylenediamine by gas chromatograph quantitative analysis of the product . The results show that : at room temperature and under atmospheric pressure , the three catalyst showed good catalytic activity , the higher the yield of p-phenylene diamine , the catalyst is easily separated from the reaction system , while the reaction time and the catalyst palladium content , temperature , substrate concentration , and other factors , the impact of the catalytic hydrogenation of p-nitroaniline , examine the stability of the catalyst .
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