负载型Rh催化剂上对氨基苯甲酸加氢反应研究

Study on the Hydrogenation of 4-Aminobenzoic Acid over Supported Rh Metal Catalysts

针对对氨基苯甲酸加氢合成对氨基环己烷甲酸反应,制备出了高效负载型Rh催化剂.考察了载体对催化剂反应性能的影响,发现γ-Al2O3是较好的载体.在80℃、8.0MPa反应条件下,对氨基环己烷甲酸收率为84.6%.Rh/γ-Al2O3催化剂在反应后活性逐渐降低,这是由于γ-Al2O3载体与溶剂水作用转变为AlO(OH),改变了Rh与载体间的相互作用所致;此外,由于催化剂在反应过程中发生积炭,同样会导致催化剂活性降低.

The supported Rh metal catalysts used for the synthesis of 4-aminocyclohexanecarboxylic acid （4-ACCA） by the hydrogenation of 4-aminobenzoic acid were prepared, γ-Al2O3 was found to be the best support. Under the reaction conditions described as follows： reaction temperature of 80 ℃, catalyst amount of 1 g/5g 4-aminobenzoic acid and reaction time of 4h, the yield of 4-ACCA reached 84.6%. After the reaction, the catalytic activity of Rh/γ-Al2O3 would decrease gradually because γ-Al2O3 would be changed into AlO（OH） for the interaction between γ-Al2O3 and water during the reaction, which would influence the interaction between support and Rh consequently. In addition, the formation of coke deposition would also result in the deactivation of the catalyst.