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分别以活性炭(AC)、γ-Al2O3、MgO、TiO2为载体,氯铂酸为活性金属前驱体,采用等体积浸渍法制得不同载体负载的Pt催化剂,考察了它们对环己烯基环己酮(dimer)脱氢制备邻苯基苯酚(OPP)的催化活性和选择性。并用X射线衍射(XRD)、X射线光电子能谱(XPS)、H2程序升温脱附(H2-TPD)、CO2程序升温脱附(CO2-TPD)等对催化剂进行表征。结果表明,载体对所制备的催化剂表面Pt含量、酸碱性和对氢吸附能力等微观性能有影响,以γ-Al2O3为载体制备的Pt-K/γ-Al2O3催化剂,由于催化剂表面Pt质量分数高达0.41%,碱性强和碱中心多,利于氢和中间产物在催化剂表面的吸附,从而提高环己烯基环己酮的转化率和OPP选择性。Pt/γ-Al2O3催化剂在LHSV 0.12 h-1、H2空速33 mL/(g.h)、反应温度380℃的条件下,在200 t/a的工业化装置运转8 000h后,环己酮二聚物转化率仍能达99%以上,OPP选择性达90%以上。
Pt catalysts supported on different supports were prepared by the same volume impregnation method using activated carbon (AC), γ-Al2O3, MgO, TiO2 as carrier and chloroplatinic acid as active metal precursor, respectively. Their catalytic activities on cyclohexenylcyclohexanone (dimer) dehydrogenation of o-phenylphenol (OPP) catalytic activity and selectivity. The catalysts were characterized by XRD, XPS, H2-TPD and CO2-TPD. The results showed that the supported Pt-K / γ-Al2O3 catalyst prepared on γ-Al2O3 as a catalyst had a significant effect on the Pt content, acid-base and hydrogen adsorption capacity. The Pt content on the catalyst surface Up to 0.41%, strong alkalinity and more base, which favors the adsorption of hydrogen and intermediates on the catalyst surface, thus improving the conversion of cyclohexenylcyclohexanone and OPP selectivity. Pt / γ-Al2O3 catalyst in the LHSV 0.12 h-1, H2 airspeed 33 mL / (gh), the reaction temperature of 380 ° C under the conditions of 200 t / a industrial device operation 8 000h, cyclohexanone dimer Conversion rate can still reach more than 99%, OPP selectivity of more than 90%.