酸改性海泡石负载钌-硼合金催化苯选择加氢制环己烯

Ru-B Alloy Supported on Acid Modified Sepiolite Used as Catalyst in Selective Hydrogenation of Benzene to Cyclohexene

以酸改性海泡石负载的钌-硼合金为催化剂,采用苯选择加氢制环己烯为探针反应,考察了反应压力、温度、水与苯体积比、催化剂用量等因素对反应的影响;并与以未经酸改性的海泡石为载体的催化剂进行了对比;采用程序升温脱附(TPD)、H2-TPD、环己烷-TPD、环己烯-TPD、程序升温还原等方法对催化剂进行了表征。实验结果表明,苯选择加氢制环己烯的最佳反应条件为:393 K、3.5 MPa、苯10 mL、水与苯体积比1、催化剂用量0.1 g;以酸改性海泡石为载体的钌-硼合金催化剂的活性和选择性均高于以未经酸改性的海泡石为载体的催化剂,这主要是由于前者具有更大的比表面积和孔径,环己烯更易脱附,从而减小其深度加氢的几率。

Selective hydrogenation of benzene to cyclohexene was chosen as probe reaction to study catalytic performances of Ru - B alloy supported on acid modified sepiolite. Effects of temperature, pressure, water and benzene volume ratio, and catalyst dosage on reaction were studied. The catalytic properties of Ru - B alloy supported on unmodified sepiolite were also studied as comparison. The catalysts were characterized by means of temperature programmed reduction （TPR）, and temperature programmed desorption （TPD） of hydrogen, cyclohexene and cyclohexane. Under optimal reaction conditions ：393 K,3.5 MPa,benzene 10 mL, V（water） ： V（benzene） = 1 and catalyst dosage 0.1 g, the catalyst with acid modified sepiolite as support exhibited higher catalytic activity and selectivity than the unmodified. The positive results were attributed by higher special surface area, higher pore size of the former. Cyclohexene was easier to be desorbed from the former than from the latter. Thus chance of further hydrogenation of cyclohexene decreased.