复合雷尼铜催化剂在乙酸酯加氢中的应用

Application of Raney Cu composite catalysts in the hydrogenation of ethyl acetate

在催化反应中,雷尼合金催化剂通常以粉末状出现,其易燃、操作不便,多用于精细化工领域中小规模的加氢反应中,而无法用于一般固定床反应。为了扩大雷尼合金催化剂的应用领域,采取一定方法将其成型成为近年来较为关注的研究方向。传统的将催化剂成型、焙烧的方法容易导致催化剂颗粒烧结,使得金属利用率低,导致活性下降。本文介绍了一种碳载体雷尼催化剂的制备方法,该方法可将催化剂的制备、成型一步完成,该方法不仅是一种催化剂的成型方法,更是一种新型催化剂的制备方法。对碳载体合金催化剂进行了一系列的物化表征发现,催化剂为疏松状结构,具有丰富的孔道及次级孔道,且高温并未导致活性金属粒子的烧结,活化后的活性金属粒径大约在50nm,均匀分散于复合载体中。在乙酸酯加氢反应中,在相同的反应条件下(反应温度为250℃,反应压力为3.0MPa,氢酯摩尔比为37,乙酸酯的液体空速为0.25h 1),该碳载体合金催化剂具有很高的加氢活性,单位质量铜表面的乙酸酯加氢转化率是传统雷尼合金催化剂的两倍。

Raney alloy catalysts typically appear as powder in catalytic reactions,which cannot be used in fixed-bed reactor due to the shortcomings of flammability and inconvenient to operation.In order to expand the applications of the Raney alloy catalysts,molding becomes the focus of recent research of these catalysts.Conventional molding and calcining of the catalysts easily lead to considerable sintering of the catalyst particles,low metal utilization and decreased activity.This article introduces a method for preparing a new alloy composite catalyst,which can accomplish the preparation and molding of the catalyst in one step.A series of physical and chemical characterizations were carried out for the new Raney alloy catalyst and it was found that the catalyst has a loose structure,with extensive channels with secondary ones.The high temperature didn't cause the metal particles to sinter and the size of the active metal particle was about 50nm,uniformly dispersed in the catalyst.The catalyst performance in the hydrogenation reaction was evaluated.Under the optimal reaction conditions of temperature 250℃,pressure 3.0MPa,n(H2):n(ethyl acetate)37 and LHSV 0.25h-1,the new complex catalyst has a high activity two times as the conventional one.