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Ru-Zn/[BEIM]Cl催化剂的制备及其性能研究

Studying on Synthesis and the Behaviour of Ru-Zn/[BEIM]Cl

【作者】 刘俊红

【导师】 王艳辉;

【作者基本信息】 北京化工大学 , 化学工程与技术, 2010, 硕士

【摘要】 过渡金属钌催化性能优异,对烃类化合物加氢反应有特殊的活性和选择性。离子液体具有无毒、无蒸汽压等特性,近年来倍受研究者青睐。离子液体催化剂易于与产品分离,属于环保型绿色催化剂。本文以N-乙基咪唑与氯代正丁烷为原料,制备了离子液体[BEIM]Cl,再以离子液体[BEIM]Cl、RuCl2、ZnCl2为组分制备催化剂Ru-Zn/[BEIM]Cl。RuCl2以RuCl3为原料,采用氢气还原法制备。离子液体制备过程中考察了溶剂种类、物料比、溶剂加入量、反应时间、反应温度等对合成过程的影响,优化了合成工艺条件,[BEIM]Cl合成的理想工艺条件是:N-乙基咪唑与氯代正丁烷比例为1:1.2(摩尔比);溶剂二甲苯加入量为每克N-乙基咪唑0.9mL;共沸温度为103℃;反应时间为18h。在最佳工艺条件下反应时,离子液体的收率可达95%。三价钌还原过程中,采用氢气做还原剂,还原工艺条件是:反应压力1Mpa;反应温度30℃;还原时间20min。离子液体催化剂制备过程中考察了催化剂组分RuCl2与ZnCl2的配比、RuCl2与离子液体[BEIM]Cl的配比对催化剂制备过程的影响。对制备的离子液体催化剂Ru-Zn/[BEIM]Cl进行了苯加氢性能研究,研究发现该催化剂对苯加氢有活性,催化剂活性与催化剂加入量、反应温度、反应压力等有关,催化剂活性越高,生成环己烯的选择性越低,生成环己烷的选择性越高。在下列条件下:RuCl2和ZnCl2的摩尔比为1:8;RuCl2与离子液体[BEIM]Cl的摩尔比为1:40;RuCl2与苯的摩尔比为1:900;苯与水的体积比为2:3;反应压力为0.9Mpa;反应温度为50℃;反应4h时,环己烯的选择性达到31.96%。变换催化剂组成及操作条件:RuCl2与ZnCl2的摩尔比为1:3;RuCl2与离子液体[BEIM]Cl的摩尔比为1:10;RuCl2与苯的摩尔比为1:225;苯与水的体积比为1:10;反应压力为0.9Mpa;反应温度为50℃;反应15h时,苯的转化率可达99%以上,环己烷选择性达99%以上。

【Abstract】 Ruthenium is a kind of transition metal, which has especial catalytic activity and selectivity on hydrocarbon hydrogenation. With non-toxic, non-vapor and other characteristics, ionic liquid has become widely accepted. Ionic liquid catalyst is easy to separate from system and friend to envionment, which belongs to green catalyst. In this paper, N-ethyl imidazole and chloro-butane is used to prepare the ionic liquid [BEIM]Cl. We prepare the catalyst with the ionic liquid [BEIM]Cl、RuCl2 and ZnCl2 as the components. RuCl2 is prepared by RUCl3 with hydrogen as reducer.During the preparation of ionic liquid, we study the effect of solvent types, solvent dosage, reaction temperature, reaction time and others on [BEIM]Cl synthesis process and optimize the synthesis conditions. The optimal factors of synthesis are as follows:solvent is xylene; the quantity of xylene is 0.9mL per gram N-ethyl imidazole; N-ethyl imidazole:C4H9Cl=1:1.2(mole ratio) at its azeotropic temperature for 18h, and the yield of product is above 95%.During RuCl3 reduction process, we use hydrogen as reducer, the reduction conditions is as follows:reaction pressure is 1Mpa, reaction temperature is 30℃, reaction time is 20min. We investigated the effect of the ratio of RuCl2 and ZnCl2, the ratio of RuCl2 and ionic liquid [BEIM]Cl on the ionic liquid catalyst preparaction.We do the performance evaluation of Ru-Zn/[BEIM]Cl catalyst using the benzene hydrogenation as probe reaction. We find that the catalyst has the activity on benzene hydrogenation. We disscused the effect of the amount of catalyst reaction time reaction temperature and others on benzene hydrogenation. The higher catalytic activity, the selectivity of cyclohexene is lower and the selectivity of cyclohexane is higher. Under the following conditions:the molar ratio of RuCl2 and ZnCl2 is 1:8; the molar ratio of RuCl2 and [BEIM]Cl is 1:40; the molar ratio of RuCl2 and benzene is 1:900; the volume ratio of benzene and water is 2:3, reaction pressure is 0.9Mpa; reaction temperature is 50℃; reaction time is 4h, the cyclohexene selectivity is 31.96%. Changing catalyst composition and operating conditions:the molar ratio of RuCl2 and ZnCl2 is 1:3; the molar ratio of RuCl2 and [BEIM]Cl is 1:10; the molar ratio of RuCl2 and benzene is 1:225; the volume ratio of benzene and water is 1:10, reaction pressure is 0.9Mpa; reaction temperature is 50℃; reaction time is 15 h, the conversion of benzene is over 99%, cyclohexane selectivity is above 99%.

【关键词】 离子液体催化剂性能
【Key words】 ionic liquidRucatalysisbehaviour
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