Preparation And Recycling Of Rh/C For Aromatic Hydrogenation

Aromatic compounds are widely existed in the petroleum fractions, high aromatic content in diesel fuel has been recognized to lower the fuel quality. Aromatic hydrogenation is one of the most useful ways to lower the aromatic content, most hydrogenation product of aromatic compounds are important chemical intermediates widely used in the chemical and pharmaceutical industries. At present, the most widely used catalysts for aromatic hydrogenation are ruthenium-based catalysts, Ru/Cå'ŒRU/Al2O3 stand for the heterogeneous catalysts of ruthenium-based catalysts. Compared to the relatively critical reaction conditions of ruthenium series catalysts and the difficulties of the recycling, rhodium-based heterogeneous catalysts gain increasing emphasis.In this paper, the acitivity and selectivity of Rh/C were evaluated by the hydrogenation of 3-ethyl 2-methyl 6-hydroxy-3,4-dihydroisoquinoline-2,3(1#)-dicarboxylate. The influnences of the activated carbon type, Rh precursor, the loading amount of Rh, the immersion time, the transition pH value and reducing conditions were investigated then. Results showed the catalyst prepared by the impregnation liquid phase reduction method made reaction conversion rate reached 100%, selectivity over 96%.(Carrier:wood activated carbon actived by phosphoric acid; precursor:RhCl3·3H2O; transformation pH: 11.5; reducing agent:H2 and HCOONa; loaded content:3%)This paper then investigated the performance of the catalyst on the hydrogenation of phenol and anthracene, it was found that the limitations of Rh/C was relatively large. Finally, the paper investigated the reusing frequency of the catalyst and did some research on recycling of spent catalyst using anion exchange resin, with the purpose of cutting the industrial cost and providing some reference for the future improvement of the catalyst performance and reaction conditions.