采用浸渍法制备己二腈加氢合成己二胺催化剂Ni-MgO/Al2O3,通过BET,XRD,H2-TPR对不同MgO负载量催化剂进行表征与测试,探讨MgO负载量对催化剂活性的影响.实验结果证明:Ni-MgO/Al2O3催化剂中MgO-NiO固溶体的形成有利于提高催化剂碱性活性位数量,能有效抑制加氢过程脱氨副反应的发生.通过单因素实验考察不同实验条件对己二腈加氢制备己二胺反应收率和选择性的影响,确定最优实验条件为:以乙醇为溶剂,催化剂中MgO负载量(ω)6％、反应温度70℃、氢气分压1.5 MPa、m(乙醇)/m(己二腈)=2.0、搅拌速率1000 r/min、催化剂用量为原料质量的5％.在此条件下,己二腈的转化率达到99.9％,己二胺的选择性达到98.4％以上.%Ni-MgO/Al2O3 catalysts for hydrogenation of adiponitrile to hexamethylenediamine were prepared by impregnation method and the prepared catalysts were characterized by BET, XRD and H2-TPR techniques. The effect of various MgO contents on catalyst activities was studied. Results indicated that the formation of MgONiO solid solution in Ni-MgO/Al2O3 catalysts increased the number of alkaline active sites which could effectively inhibit the side reaction of deamination. The effect of reaction conditions on the yield and selectivity of hexamethylenediamine was investigated base on single factor experiments. The optimal reaction conditions were determined as follows: using catalyst with MgO mass content of 6% and a dosage of 5% (based on total mass of raw materials) , adopting ethanol as solvent, a reaction temperature of 70 ℃ , a hydrogen partial pressure of 1. 5 MPa, ethanol/adiponitrile mass ratio of 2. 0 and with a stirring speed of 1 000 r/min. Under such optimal conditions, the conversion of adiponitrile and the selectivity of hexamethylenediamine reached 99. 9% and over 98. 4%, respectively.
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