合成碳酸二甲酯PdCl_2-CuCl_2-KOAc/AC催化剂失活过程分析  

ANALYSIS OF DEACTIVATION OF PdCl_2-CuCl_2-KOAc/AC CATALYST FOR SYNTHESIS OF DIMETHYL CARBONATE

作　　者：王淑芳[1] 崔咏梅[1] 赵新强[1] 王延吉[1] 

机构地区：[1]河北工业大学绿色化工与高效节能河北省重点实验室,天津300130

出　　处：《化工学报》2004年第12期2008-2014,共7页CIESC Journal

基　　金：国家自然科学基金资助项目 (No 2 0 1760 0 8)~~

摘　　要：对气相直接合成碳酸二甲酯PdCl2 CuCl2 KOAc/AC催化剂失活问题进行了研究 .结果表明 :反应过程中氯的流失 ,使催化剂表面Cu2 + /Cu+ 与Pd2 + /Pd0 比例发生变化 ,这是影响催化剂稳定性、造成催化剂可逆失活的一个重要因素 .钯组分的流失、催化剂表面积炭和金属颗粒聚集等因素则直接造成了催化剂的不可逆失活 .考察了不同反应条件对催化剂稳定性的影响 ,发现降低反应温度、提高反应压力和进料中氧气浓度可在一定程度上提高催化剂的稳定性 .原料中配入一定浓度的含氯有机物作为补氯剂 ,可有效延长催化剂的寿命 ,当反应压力为 0 3MPa,补氯剂浓度为 5 % (体积分数 )时 ,反应 15 0h后催化剂活性仍可稳定在 70 0～ 75 0 g·L-1·h-1.The deactivation of PdCl2-CuCl2-KOAc/AC catalyst for gas-phase direct synthesis of dimethyl carbonate and the effects of reaction conditions on the catalyst stability were studied. The possible active centers were Pd2+ and Cu+. Treating the catalyst with chloro-organic compounds could increase the content of Cu2+ and Pd2+ on the surface of the catalyst. Cu2+ is the oxidant of Pd0. The synergistic effect between Pd and Cu could complete the oxidation-reduction cycle between Pd2+/Pd0 and Cu2+/Cu+. With the loss of Cl- anion, the ratios of both Cu2+/Cu+ and Pd2+/Pd0 were changed. This change was one of the main reasons for the reversible deactivation of the catalyst. The loss of Pd component, carbon deposition and aggregation of metal particles were the main reasons for the irreversible deactivation. The stability of the catalyst could be improved by increasing the reaction temperature or by lowering the reaction pressure and the concentration of oxygen in the feed. The chloro-organic compounds added in the feed could increase the service time of the catalyst effectively. The activity could be kept stable for more than 150 h at the STY of 700-750 g &middot L-1 &middot h-1 when the reaction pressure was 0.3 MPa and the concentration of the chloro-organic compound was 5% (vol).

关 键 词：碳酸二甲酯 气相直接合成 催化剂 失活 

分 类 号：TQ203.2[化学工程—有机化工] TQ223.27