【作者】 谢方明；

【导师】 罗国华；

【作者基本信息】 北京化工大学 ， 化学工程与技术， 2012， 硕士

【摘要】 目前,有关烷基苯合成方法的研究大多集中在以固体酸为催化剂催化苯与烯烃或相应的一元醇的烷基化反应,而以离子液体催化剂催化氯代烷烃与苯的烷基化反应合成相应的烷基苯的研究鲜有报道。论文以2-氯丙烷和氯代叔丁烷为烷基化剂,以氯铝酸盐离子液体为催化剂,展开了异丙苯及叔丁苯合成的研究,并对离子液体催化氯代烷烃与苯的烷基化反应机理进行了探讨。论文分别采用吡啶和乙腈作为探针分子,采用傅立叶变换红外探针法对所合成的离子液体进行酸性表征,结果表明氯铝酸盐离子液体的酸性主要由阴离子决定。在苯与2-氯丙烷烷基化反应合成异丙苯的过程中,分别考察了不同阳离子的离子液体、不同AlCl3/[Et3NH]Cl摩尔比、苯/2-氯丙烷摩尔比、离子液体催化剂加入量、反应温度等条件对烷基化反应的影响,并对不同类型离子液体催化剂的反应活性及重复使用情况进行了考察。结果表明,离子液体[Et3NH]Cl-2AlCl3具有相对较好的催化活性,异丙苯的选择性随着苯/2-氯丙烷摩尔比、离子液体加入量及反应温度的提高而增大,在适宜的反应条件下,即以离子液体[Et3NH]Cl-2AlCl3为催化剂,苯/2-氯丙烷摩尔比为3.3:1,离子液体加入量为苯质量的10%,反应温度为55℃,苯的转化率为29.3%,2-氯丙烷完全转化、异丙苯选择性为90.1%。离子液体[Et3NH]Cl-2AlCl3具有最好的催化活性和重复使用性,在重复使用5次之后,催化活性未见明显下降,温度对离子液体重复性无明显影响。论文同时对在苯与氯代叔丁烷烷基化反应合成叔丁苯进行了研究,考察了不同阳离子的离子液体、苯／氯代叔丁烷摩尔比以及反应温度等条件对烷基化合成叔丁苯的影响,并且分别以新鲜苯和通过精馏分离回收未反应的苯作为为原料,着重考察了[Et3NH]Cl-2AlCl3离子液体的重复使用性。结果表明,[Et3NH]Cl-2AlCl3离子液体催化剂对催化苯与氯代叔丁烷烷基化反应有很好的效果,提高苯／氯代叔丁烷摩尔比和反应温度,均有利于提高叔丁苯选择性。在应温度为55℃,苯／氯代叔丁烷摩尔比为2.9,[Et3NH]Cl-2AlCl3离子液体加入量为苯质量的10%的反应条件下,苯的转化率可达到32.5%,氯代叔丁烷转化率为100%,叔丁的选择性为91.2%,副产物主要为二叔丁基苯,没有发现三叔丁基苯产物。离子液体可重复使用4次,采用回收苯作为原料并未发现对离子液体重复性有明显的影响,通过对失活的离子液体进行补铝可以实现离子液体的再生,为下一步在山东菏泽2000吨／年叔丁苯中试提供了许多值得参考的数据,并确定了中试工艺流程。氯铝酸盐离子液体催化氯代烷烃与苯的烷基化反应属于典型的Friedel-Craft烷基化反应,属于碳正离子反应机理。碳正离子的稳定性及活泼程度决定了反应进行的难易,通过对比2-氯丙烷与氯代叔丁烷与苯的烷基化反应结果表明,相同反应条件下,苯与氯代叔丁烷烷基化反应相对于与2-氯丙烷的反应更容易进行,这是由于其碳正离子稳定性不同所致。更多还原

【Abstract】 At present, most of researches on preparaing alkylbenzene focus onthe alkylation of benzene with olefin or monohydric alcohol, however, theakylation of benzene with chlorinated paraffins catalyzed by ionic liquidwas rarely reported. In this paper,2-chloropropane and tert-butyl chlorideare used as alkylating reagent to alkylate with benzene to prepare cumeneand tert-butyl benzene, and the mechanism of alkylation reactioncatalyzed by ionic liquid is also discussed.Firstly, we use pyridine and acetone as a probe molecular tocharacterize the acid activity of ionic liquids, the result showed that theacidity of the chloro-aluminated ionic liquids is mainly decided by theanion. In the process of preparing cumene, we investigate the effect ofionic liquids of different cation, mole ratio of AlCl3to [Et3NH]Cl, moleratio of benzene to2-chloropropane, amount of ionic liquid and thereaction temperature on alkylation of benzene with2-chloropropane. Inthe same time, and studied the influence ionic liquids of different cationon the activity and reusability of chloro-aluminate ionic liquids. The result showed that,[Et3NH]Cl-2AlCl3shows the better catalytic effect,and increasing the mole ratio of benzene to2-chloropropane, amount ofionic liquid, and reaction temperature can lead to the promotion of theselectivity of cumene. The ideal reaction condition is that, using[Et3NH]Cl2AlCl3as catalyst, the amount of catalyst was10%wt ofbenzene, mole ratio of benzene to2-chloropropan was3.3and thereaction temperature was55, under the ideal reaction condition, theconversion of benzene was29.3%, and the selectivity of cumene was90.1%.[Et3NH]Cl-2AlCl3can also show the best reusability, after fivetimes of reusing, the catalytic effect did not significantly change.In the process of preparing tert-butyl benzene, we investigate theeffect of ionic liquids with different cation, mole ratio of benzene totert-butyl chloride, and the reaction temperature on alkylation of benzenewith tert-butyl chloride, and also use both fresh benzene and benzene ofrecycling as material to study the reusability of chloro-aluminate ionicliquids. The result showed that,[Et3NH]Cl-2AlCl3shows the bestcatalytic effect, with the increasing of mole ratio of benzene to tert-butylbenzene and the reaction temperature, the selectivity of tert-butyl benzeneshows an upward trend. The ideal reaction condition is that, the amountof catalyst was10%wt of benzene, mole ratio of benzene to tert-butylchloride was2.9and the reaction temperature was55. Under the idealreaction condition, the conversion of benzene was32.5%, and the selectivity of tert-butyl benzene was91.2%. Only di-tert-butyl benzenewas detected in the byproduct. The catalyst of [Et3NH]Cl-2AlCl3can bereused for four times, and it shows no obvious influence on thereusability of ionic liquid with the recovery of benzene as a feedstock, theinactivation of ionic liquid can be regenerated via adding AlCl3. It alsoprovides a lot of reference data for2000t/a pilot in Heze and determinesthe pilot process.Alkylation of benzene with Chlorinated paraffins catalyzed by ionicliquid was the typical Friedel-Craft reaction, it obeys the mechanism ofcarbocations, the reaction activity mainly depends on the stability andactivity of carbocations, by comparing the process of synthesis of cumeneand tert-butyl benzene, we can see that, under the same reaction condition,the alkylation of benzene and chloro-tert-butane alkylation can be easierthan the reaction with2-chloropropane, this is due to the difference ofstability of carbocations.更多还原