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The Study Of Selective Catalystic Hydrogenation Of Aromatic Ketone For Aromatic Alcohol

Posted on:2013-11-07Degree:MasterType:Thesis
Country:ChinaCandidate:D S MengFull Text:PDF
GTID:2181330467483990Subject:Chemical Engineering and Technology
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Aromatic alcohols are the vital chemical products which are widely used in theproduction of spices, medicine and other fine chemical products. In this paper, thearomatic alcohols we prepared contain a chiral carbon atom and are the efficient rawmaterials in the preparation process of chiral aromatic alcohols. In the numerous synthesismethods of aromatic alcohols, much more attention on the catalytic hydrogenation ofaromatic ketones has been attracted due to the atomic economy.In this paper, we prepared aromatic alcohols through the heterogeneous catalytichydrogenation of aromatic ketones, with the Raney Ni as catalyst, hydrogen as thehydrogen source.In the catalytic hydrogenation of acetophenone to1-phenylethanol experiments, theeffects of reaction conditions, such as the reaction temperature, reaction pressure, alkali,solvent and different Raney Ni, had been explored. The experiment results indicated thatthe selectivity of1-phenylethanol reached99.47%under optimal catalytic hydrogenationconditions with T=50℃, P=3.0MPa, water as the solvent, triethylamine as the alkali andthe Raney Ni Ⅲ as the catalyst.According the results of catalytic hydrogenation of acetophenone, the Raney Nicatalysts prepared in different ways have a great influence on the selectivity of1-phenyethanol. The selectivity of Raney Ni Ⅰon1-phenyethanol reached95.19%,Raney Ni Ⅱreached98.23%and Raney Ni Ⅲ reached99.47%, and the yield of1-phenyethanol reached92.5%,95.21%and97.43%, respectively. The structure of1-phenyethanol was confirmed by the method of gas chromatography.The catalytic hydrogenation exeperiments of aromatic ketones were carried out,including1-(4-methylphenyl)-ethanone,1-(4-ethylphenyl)-ethanone, propiophenone,1-(4-methylphenyl)-1-propanone and1-(4-ethylphenyl)-1-propanone, the reactionconditions were chosen according to the optimal conditions of acetophenonehydrogenation, that were P=3.0MPa, triethylamine as the alkali and water as the solvent.The results of aromatic ketones hydrogenation experiments showed that the selectivity ofcorresponding aromatic alcohols was all more than98%and the yield was above91%.This indicated that the selectivity of Raney Ni Ⅲ on producing aromatic alcohols wasalso better in the process of these aromatic ketones hydrogenation. A series of characterization methods, including XRF, XRD, N2physical adsorption,XPS, SEM, HRTEM and H2-TPD, were adopt for the three kinds of Raney Ni catalysts.For the Raney Ni Ⅲ catalyst with the highest selectivity, the bulk composition wasNi98.9Al1.1, and contained a small amount of3Ni(OH)2·2H2O in addition to Ni which wasthe only component in the other two Raney Ni catalysts. And the crystalline size, porevolume, pore diameter and BET surface areas increased with the contents of the oxidationstate of nickel on the Raney Ni surface was twice as great as the other two Raney Nicatalysts. The surface of Raney Ni Ⅲ was more smooth, and the grain dispersed well.The curve of H2-TPD showed that there were two TPD peaks with356K and554K, andthe content of hydrogen corresponding to the554K peak was higher. The structure ofRaney Ni Ⅲ is beneficial to the adsorption of carbonyl, which leads to the higherselectivity.In this paper, aromatic alcohol were obtained by catalytic hydrogenation of aromaticketone with the Raney Ni as catalyst, water as solvent, and the selectivity was higher than98%, the yiled was above91%. Besides, water was adopted as the hydrogenation reactionsolvent instead of the organics, which agreed with the chemical concepts of green,environmental protection, and sustainable development those were advocated currently. Asto the preparation method of Raney Ni, the method in this paper is a new breakthrough.
Keywords/Search Tags:Hydrogenation of aromatic ketone, Aromatic alcohol, Raney Ni catalyst, Heterogeneous catalytic hydrogenation, Water
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