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Hydroxyapatite -based efficient multiphase nano gold catalytic materials to build their application in the the green selective oxidation reaction

Author: SunHao
Tutor: CaoYong；FanKangNian
School: Fudan University
Course: Physical and chemical
Keywords: hydroxyapatite gold nanoparticle alcohol oxidations tandem reactions multi-functional
CLC: O643.3
Type: Master's thesis
Year: 2010
Downloads: 103
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Abstract

Since the discovery of gold catalysts can show excellent catalytic behavior for CO oxidation in the low temperature in the late of 1980’s, intensive and extensive research efforts have been devoted to the subject of Au catalysis. One recent focus in this field is the organic reaction and fine chemicals synthesis through efficient methodology of oxidation, reduction and coupling under mild reaction condition.Hydroxyapatite (HAP) is similar in chemical characters and compositions to that of inorganic calcium phosphate of natural bone. It is widely accepted for bone and tissue substitutes with low-bearing due to its excellent biocompatibility and bioactivity. HAP also can be used to treat wastewater with ability in physisorptions and chemisorptions. In decade, according to the unique properties of HAP, such as ion-exchange ability and modification, plenty of new functional materials have been exploited and widely employed in many research fields and practices. Also, HAP-based material acting as a catalyst shows its advantage in heterogeneous catalysis system.In this dissertation, Au/HAP has been designed and employed as a heterogeneous catalyst in liquid-phase organic reaction, including alcohol oxidation and direct tandem synthesis of imines, oximes and amides. It was found that the acid/basic properties of support, support-metal interaction and particle size effect of Au played important roles in the reaction system. It was also demonstrated that HAP with unique characteristics might function as a co-catalysts for particular reactions by not only stabilizing gold nanoparticles but facilitating the process of any steps of these reaction as well.Part 1:A series of Au/HAP with different Ca/P molar ratios have been designed and employed in the aerobic oxidation of 1-phenylethanol. It revealed a definite correlation between the surface basity of the HAP support and alcohol-dehydrogenation capability, indicating that the dehydrogenation capability was the key factor for alcohol oxidation reactions. And Au/HAP (Ca/P=1.67) showed its best reaction performance among these four catalysts.The present HAP-supported gold catalyst system showed a wide applicability for various different structure alcohols oxidation, especially for aliphatic alcohols, such as cyclohexanol,2-octanol. Also, Au/HAP could be recycled without appreciate activity lost.Part 2:Based on the previous work, elements Cl and F have been applied and occurred into the HAP material structure in order to improve the catalytic performance. Au/FAP showed its superior catalytic activity for aerobic oxidation of alcohols, especially in the water-phase reaction system.Part 3:Au/HAP possessing a unique amphoteric character was an efficient multifunctional catalyst for rapid direct synthesis of imines, oximes and amides from amines under mild conditions by a facile tandem oxidation-condensation pathway. A new synthesis method has also been successfully designed for the one-pot three-component syntheses of a-aminophosphonates in solvent-free conditions

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