Heterogeneous Catalytic Hydrogenation Of Amino Acid Methyl Esters To Amino Alcohols Over Mg-modified Cu/ZnO/Al₂O₃ Catalyst

Chiral compounds are widely used in fine chemical industries, medicine, etc. Since amino alcohol molecule has good coordination ability of N and O atoms which can form complex with a variety of- elements, it is an important chiral ligands and widely used in the chiral catalysts, and chiral resolution of racemic mixture and many kinds of organic synthesis reaction, etc. Therefore, the green synthesis of chiral amino alcohols high ee value has the extremely important significance for the academic and practical works.In this thesis, the CuZn0.3Mg0.1AlOx, catalyst for the preparation of chiral amino alcohols were prepared in larger scale, and 8 kinds of amino acid methyl esters were used to prepare corresponding chiral amino alcohols by heterogeneous catalytic hydrogenation. The preparation of R-phenylglycinol was used as a model reaction, the reaction conditions (the temperature, pressure, catalyst amount, reaction time, etc.) were investigated, and the stability of prepared catalyst was tested also. The main results are obtained as follows.The CuZn0.3Mg0.1AlOx, catalyst for the synthesis of chiral amino alcohols was prepared by the fractional co-precipitation method in the 50?100g scale, which is larger 10 times than that reported. The preparation conditions (the rate of coprecipitation, pH in the synthesis solution,stirring speed. etc) on the catalytic performance were studied. The optimal preparation conditions were determined by the help of the characterization of the catalyst, such as, the speed of coprecipitation of 0.2 mL/s. the pH of 7.5 in the synthesis solution, the stirring speed of 900 r/min, and the precipitation temperature of 30?. The stability of catalyst was also tested. After repeated usage 16 times, its catalytic activity was hardly varied and the yields of R-phenylglycinol were kept in 85.6% ?87.7% with ?100 % ee value, which show that this catalysts have good stability. And the reaction activation energy (Ea) was tested to be 36.7 kJ/mol.For the hydrogenation of R-phenylglycine methyl ester to R-phenylglycinol, the effect of the reduction gas on the catalytic activity, and the effects of the reaction conditions(R-p-m/Cat, temperature, reaction time. H2 pressure and solvent) on the catalytic hydrogenation of R-phenylglycine methyl ester (marked as R-p-m) were investigated. The results shows that the catalyst reduced by pure hydrogen exhibited the best catalytic activity,and the most appropriate reaction condition is. ethanol as solvent, the reaction temperature of 80?, the ratio of catalyst/raw material of 1/1.5, the reaction time of 10 h and the hydrogen pressure of 5 MPa.To expand the use range of this catalyst, other 7 kinds of amino acid methyl ester were used as the reaction substrates,and 7 kinds of corresponding amino alcohols with ?100% ee value were obtained. It shows that the yields of L-phenylalaninol and R-phenylglycinol are relatively high, but the yield of L-tyrosinol is relatively low, which is possibly that the chloride in tyrosine methyl ester hydrochloride adsorbed on the catalyst, resulting in a deactivation of the catalyst in the hydrogenation process.