Catalytic Amination Of N-Octyl Alcohol Based On Modified Ni Catalyst

Amine derivatives are widely used in various fields of life.The process route for preparing organic amines from organic alcohols has become a research hotspot because of its easy availability of raw materials,relatively mild reaction conditions and compliance with the concept of green environmental protection.Ni is often used for the amination reaction of organic alcohols due to its excellent hydrogenolysis ability and low price.The catalytic amination of n-octanol was used as a template reaction to compare the catalytic performance of supported Ni catalysts and it's modified catalysts.The results show that 10%Ni-(?-Al2O3)is the best supported Ni catalyst.Then the catalyst was modified.Compared with 10%Ni-(?-Al2O3),the catalyst after Cr modified reached 70%conversion in the liquid phase reaction was shortened from 3.5 h to 2 h,and the selectivity of target product increased by 16%.Compared with 10%Ni-(?-Al2O3),the catalyst after the Ce2O3 modified reached 80%conversion in the liquid phase reaction was shortened from 4 h to 2 h,and the selectivity of target product was increased by 10%.XRD,H2-TPR and TEM characterization of the above three catalysts showed that the reduction ability and the Ni dispersion were significantly improved in Cr modified catalysts.After Cr modification,the diameter of the Ni particles decreased significantly.It was found by NH3-TPD that the ability of the catalyst modified by Cr to adsorb NH3 was significantly reduced,and the acid strength of the catalyst after Ce2O3 modification was significantly decreased Both of which could increase the number of active sites of the catalyst and promote the conversion of the reaction.Based on the above results,the modified Ni-Cr catalyst was selected for the fixed bed reaction of 1-octanol.The effects of reaction temperature,H2:ROH ratio,NH3:ROH ratio and GHSV on the reaction results were discussed,and suitable conditions were obtained:temperature of 200 ?,the ratio of H2:ROH?5.3,the ratio of NH3:ROH=16,the GHSV of 8000 ml/(h-1·g-1).Under this condition,the conversion of amination reaction was 62.6%,the primary amine selectivity was 72.7%.The three catalysts were continuously reacted for 30 h under the above conditions,and it was found that the amount of carbon deposited and the depth of coking of the modified catalyst were significantly decreased.