Study On Catalitic Performances Of Supported Metal Catalysts For Slective Hydrogenation Of Tetrahydro-farnesylaceton

Hexahydrofarnesylacetone is one of important basic chemical raw materials and an important intermediate for the synthesis of vitamin E.In industry,hexahydrofarnesylacetone is prepared from farnesylacetone through liquid phase hydrogenation in batch reactor.There exits many disadvantages for above intermittent reaction mode,such as low degree of automation,operational problems,hydrogen wasting,loss of the catalyst,and so on.The continuous hydrogenation process carried out in fixed bed reactor is green and with low power consumption,effectively solving the above problems.So,it is of great value both in the theory and industries to thoroughly investigate the continuous hydrogenation catalyst and reaction process.Palladium supported catalysts are often used as the selective hydrogenation catalysts for olefins,due to their high selectivity for partially hydrogenation.There are many advantages such as high palladium dispersion,big active surface,easy reactant diffusion through the pores,long life,easy separation and recovery,etc.,when palladium is loaded on the big carrier particles,such as granular activated carbon,silica and alumina.In this paper,a series of palladium supported catalysts were prepared using different methods and then used for selective catalytic hydrogenation of tetrahydro-farnesylacetone to hexahydrofarnesyl-acetone.Influences of the catalyst preparation methods,pretreatments of the carries,reaction conditions on the catalytic performance of these supported palladium catalysts were systematically investigated in this study.On the other hand,kinetics of the reaction was studied and the dynamic model was proposed.Finally the industrial larger scale reactor was preliminary designed according to the results of kinetics research.The exeprimantal results indicated 0.25wt%Pd/C prepared with especial pretreatment possessed the highest catalytic activity and selectivity.The conversion of tetrahydro-farnesylacetone is up to 99%and the selectivity towards hexahydro-farnesylacetone is more than 98%under the optimal conditions.Method of activated carbon pretreatment was as follows:firstly,the activated carbon was pretreated by water bath at 363 K for one hour with 30%of HCOOH aqueous solution,then followed by air drying for one hour.