【作者】 贾玮玮；

【导师】 刘靖；

【作者基本信息】 大连理工大学 ， 工业催化， 2008， 硕士

【摘要】 间二异丙苯是一种很重要的化工原料,主要用于氧化生产间苯二酚。近年来,随着间苯二酚在许多行业中应用的增长,对间二异丙苯的需求也日益增加。目前,在苯酚-丙酮生产工艺中苯-丙烯烷基化反应单元会生成一定量的副产品二异丙苯,由于二异丙苯三种异构体沸点极为接近,用常规的蒸馏方法很难将间二异丙苯分离出来。本文利用分子筛催化剂的择形作用对混合二异丙苯进行选择裂化,使分子构型较小的对二异丙苯进入分子筛孔道于酸中心反应裂化成苯和异丙苯,而分子构型较大的间二异丙苯留在分子筛孔道外,不发生裂化,这样所得产物由于沸点差异较大（苯80.1℃、异丙苯152.5℃）,经过精馏过程即可得到纯度为99%的间二异丙苯。本文首先对4种不同类型的沸石分子筛HZSM-5、HZSM-22、Hβ和HY的选择裂化性能进行了评价,发现HZSM-5型沸石分子筛对混合二异丙苯择形催化裂化反应有良好的选择裂化性能;不同晶粒大小的HZSM-5分子筛的反应结果表明,纳米HZSM-5分子筛的选择裂化性能最好。以纳米HZSM-5分子筛为催化剂,考察了载气、反应温度和空速对择形催化裂化反应的影响,结果表明,在氮气为载气,压力为0.1MPa,温度为380℃,质量空速为6h^-1的反应条件下,纳米HZSM-5分子筛上对二异丙苯的裂化率为93%,产物二异丙苯中间二异丙苯的含量为94%,间二异丙苯收率为75.7%。在此基础上,我们分别采用负载镁和镧的氧化物和水热处理对纳米级HZSM-5分子筛进行了改性。镁和镧的氧化物改性结果表明,催化剂在40h内反应仍能表现出较高的活性,稳定性提高,同时间二异丙苯的收率提高。其中以硝酸镁为前身物制备的催化剂比以醋酸镁为前身物制备的催化剂的裂化活性高,稳定性好;比较了不同含量镧离子对反应的影响,当La离子含量为0.1wt%时,对二异丙苯的裂化率可达92%,产物二异丙苯中间二异丙苯的含量为93%,间二异丙苯的收率提高至85%以上。对比160℃时条件下不同水热处理时间改性的纳米ZSM-5催化剂,结果表明,水热处理2h后的催化剂在50h内保持较高的活性,其稳定性最好。此外,我们还考察了水热处理和镧复合改性对催化剂稳定性的影响,结果表明,镧改性后再水热处理的催化剂比先水热处理再镧改性的催化剂稳定性好,60h内对二异丙苯的裂化率保持在85%以上,产物二异丙苯中间二异丙苯的含量保持在90%以上。更多还原

【Abstract】 Diisopropylbenzenes（DIPBs）will be formed as byproduct during manufacturing cumene by alkylation of benzene with propylene to in phenol-acetone plants,and meta-DIPB is an important raw material,which mainly can be oxidized to resorcinol. Recently with the need of resorcinol increasing in many industries,the need of m-DIPB is also increasing.However,the boiling points of the three isomers of DIPB are very close: ortho-DIPB 205℃,meta-DIPB 203℃,para-DIPB 203.5℃,so it is difficult to separate meta-DIPB from the other isomers using normal distillation.In this paper,the certain zeolites which have the shape-selective function will be used as catalysts to crack DIPBs selectively. They have the appropriate pore diameter in order to let para-DIPB go into the pores of molecular sieves and will be cracking to benzene and cumene with the acid centers inside,but meta-DIPB（larger diameter than para-）can not go inside and does not react.So 99% meta-DIPB can be producted though distillation using the obvious differences of boiling points of products,（benzene 80.1℃,eumene 152.5℃）.Shape-selective cracking of DIPB was investigated over zeolite catalysts,i.e.HZSM-5, HZSM-22、Hβand HY.The results showed that HZSM-5 zeolite appeared to be the most efficient catalysts for the reaction.Meanwhile,nano-HZSM-5 is the high-active catalyst for the reaction compared the different grain sizes of HZSM-5.The reaction conditions over nano-HZSM-5 were investigated,the cracking rate of para-DIPB can reach 93%,Content of m-DIPB in product DIPB 94%and the yield of meta-DIPB 75.7%at the optimum conditions: pressure 0.1MPa,reaction temperature 380℃,and weight hourly space velocity（WHSV）6h^-1 with N₂.Nano-HZSM-5 was modified with oxides of magnesium and lanthanum,the results show that the modified zeolites have the high activity during 40h,the stability is increasing,and the yielding of meta-DIPB is also increasing.The catalysts prepared with Mg（NO₃）₂ as the precursor of MgO have the higher cracking activity and stability than the catalysts prepared with Mg（CH₃COO）₂ as the precursor.Compared with the effects of different contents of lanthanum iron,the results indicate that 0.1%content the stability of catalysts increased obviously,and the cracking rate of para-DIPB can reach 92%,Content of m-DIPB in product DIPB 93%,the yield of meta-DIPB over 85%.Compared with modification by hydrothermal treatment in different time under the temperature of 160℃,the results indicate the catalysts modified by hydrothermal treatment in 2h hold high activity during 50h,and have the best stability.The stability of nano-HZSM-5 modified by hydrothermal treatment followed by lanthanum is better than modified by lanthanum followed by water,the cracking rate of para-DIPB can holding over 85%during 60h,Content of m-DIPB in product DIPB over 90%,the yield ofmeta-DIPB over 90%.更多还原