Studies On The Amidocarbonylation Reactions And Condensation Reaction Of Alcohols

There are two different types of catalytic reactions studied in this dissertation. In the part one it was amidocarbonylation catalyzed by palladium compounds, and in the part two, it was condensation reaction of some alcohols catalyzed by solid catalysts in vapor phase.Amidocarbonylation is a new synthetic method of N-acyl- α -amino acids, and it has great potential application in industry. Cobalt or palladium compounds were usually used as the catalysts in this reaction, and particularly palladium was efficiently applied because of its advantages of high catalytic activity, wide range of reactants and mild reaction conditions. In the present work, palladium chloride was utilized as the catalyst instead of expensive the palladium bromine in the amidocarbonylation of isovaleraldehyde and the influence of some important parameters on this reaction were examined. On the optimal reaction conditions, the isolated yield of N-acylleucine was 66.4%. The amidocarbonylation of other aldehydes such as propionaldehyde, butaldehyde, phenyl aldehyde and cyclohexanecarboxadledede were also performed and the isolated yields of products were 30-90%.Palladium catalysts are expensive, however, the homogeneous palladium catalysts are unrecoverable. To solve these problems we have prepared the heterogeneous Pd/HZSM-5 catalyst and compared it with Pd/C catalyst which had been reported in the literature. After the reaction conditions were optimized, we found that the initial catalytic activity of Pd/HZSM-5 catalyst was similar to that over Pd/C catalyst, for example, the isolated yields in the amidocarbonylation of isovaleraldehyde and cyclohexanecarboxaldehyde catalyzed by Pd/HZSM-5 catalyst were 63.1% and 89.7% respectively, in the case of Pd/C catalyst they were 65.3% and 94.3% respectively. In the catalyst recycling test, the catalytic activity of Pd/HZSM-5 kept stable at least four time runs while dramatic decline was observed in the case of Pd/C. The TEM images of these two catalysts revealed that the palladium particles ofPd/HZSM-5 catalyst kept uniform dispersion status, but the palladium particles over Pd/C catalyst agglomerated and formed a network after reaction. This observation may be attributed to palladium particles incorporation into the cages of HZSM-5 zeolite. It was the first time to report that the heterogeneous palladium catalyst was successfully recycled in amidocarbonylation.Racemic N-acyl amino acids were formed via amidocarbonylation while in most applications optically pure amino acids and their derivatives were preferred. In order to obtain optical amino acids and their derivatives, the studies were carried out in two aspects. Firstly, the racemic products obtained from amidocarbonylation were resolved by the acylase-catalyzed hydrolyzation, subsequently, 99% ee (L)- leucine and 89% ee (D)-N- acetylleucine were isolated. On the other hand, some asymmetric ligands were synthesized and then utilized in the asymmetric amidocarbonylation, but optical purities of products were very low. The possible reason was explored from their reaction mechanism. The failure of the asymmetric amidocarbonylation maybe attributed to the intermediates formed in the reaction. The intermediates were not prochiral reactant and hard to form the optical products. The asymmetric ligands were also applied in the hydroesterification of styrene. In this reaction 38.4% ee optical products were gotten under room temperature and atmospheric pressure.In the part two of this dissertation, two condensation reactions of alcohol catalyzed by solid catalysts were studied in vapor phase. These reactions can increase the carbon chains, therefore higher alcohols, aldehydes and ketones can be produced from lower alcohols, which are obtained from syngas or fermentation of agriculture products. As the exhaustion of fossil oil, it may be developed to a new route of getting the basic materials in modern chemical industry.The condensation reactions of alcohol give variety and each of them is fairly complex. In this work two typical reactions were studied, one was the condensation of ethanol and the other was condensation of methanol and butanone.In the condensation reaction of ethanol, Ni/ y -A12C^ Pd/ Y -AI2O3 catalysts were first reported. Compared these with the catalysts reported in literature, Ni/ y -AI2O3and Pd/ Y -AI2O3 catalysts performed high catalytic activities. For example, when the reaction catalyzed by Ni/ y -AI2O3, the conversion of ethanol was about 30% and the selectivity of n-butanol was 64%. Furthermore, the reaction conditions become much mild, for instance the reaction temperature decreasing about 100-200 °C . 2-ethylbutanol and n-hexanol were found in the products, and the selectivity of them reached 26%. They were formed by the condensation of ethanol and n-butanol. The primary study on the mechanism showed that the reaction was accomplished by the dehydration of $ — H.In the condensation reaction of methanol and butanone, Mg/Al mixed oxides were found to be superior catalysts. On the optimal reaction conditions, the conversion of butanone reached 60% when the mixture of methanol and butanone in 1:1 mole ratio were feed. The methanol reactant was almost completely converted because it would continually react with the products MIPK(methyl isopropyl ketone) and DEK(diethyl ketone). The selectivities of MIPK, DEK and EIPK(ethyl isoproyl ketone) were about 90% in the product.