双环戊二烯加氢NiMo_x/γ-Al₂O₃催化剂耐硫特性的研究

The effect of Mo and its addition amount on the sulfur tolerance of Ni catalyst in the hydrogenation of dicyclopentadiene (DCPD) was studied. A series of γ-Al₂O₃ supported nickel-molybdenum bimetallic catalysts were prepared by the equal volume impregnation method. The performance test of the catalyst was carried out in an autoclave, the feed ratio was the catalyst:DCPD:cyclohexane = 1:10:100. The reaction was carried out at a temperature of 150℃ and a pressure of 3.5 MPa, with a stirring speed 600 r/min. Before the reaction starts, a certain amount of thiophene was added in cyclohexane in order to know the sulfur resistance of the catalyst. When the concentration of thiophene cyclohexane solution is 500 mg/L, the hydrogenation rate of the double bond of 8, 9 position of dicyclopentadiene is significantly reduced under the catalysis of Ni/γ-Al₂O₃, and the hydrogenation activity of double bond of 3, 4 position is completely suppressed; under NiMo_0.2/γ-Al₂O₃ catalysis, however, the hydrogenation reaction is completed within 4 h, the yield of tetrahydrodicyclopentadiene (endo-THDCPD) reaches 98%, and the sulfur resistance of the catalyst is significantly improved. Among the series of catalysts with different nickel-molybdenum ratios, NiMo_0.2/γ-Al₂O₃ exhibited the best hydrogenation activity and sulfur resistance. Catalyst NiMo_0.2/γ-Al₂O₃ was tested for sulfur resistance with a thiophene concentration range of 0~2000 mg/L. When the concentration of thiophene is low, the NiMo_0.2/γ-Al₂O₃ catalyst has high hydrogenation activity and good selectivity for dicyclopentadiene; as the concentration of thiophene increases, the catalytic performance of the catalyst decreases. When the thiophene concentration is increased to 2000 mg/L, the hydrogenation reaction is extended to 6 hours, and the yield of endo-THDCPD is reduced to 95%.