Na_2CO_3溶液处理对Ni-Mo/HZSM-5分子筛硫醚化催化性能的影响

Effect of Na_2CO_3 solution treatment on the performance of Ni-Mo/ZSM-5 catalyst in thioetherfication

采用Na2CO3溶液对ZSM-5分子筛进行碱处理,考察了处理温度和处理时间对ZSM-5分子筛结构特征和物化性能的影响。利用XRD、N2吸附-脱附、XRF、SEM及NH3-TPD表征对处理前后样品进行分析。以正丁硫醇和异戊二烯组成的模型化合物为原料,对碱处理后含微-介孔HZSM-5分子筛制得的Ni-Mo/HZSM-5催化剂进行硫醚化活性评价。结果表明,Na2CO3溶液处理没有破坏原分子筛晶体形貌,保持微孔结构的同时,适当的提高处理温度和延长处理时间有利于ZSM-5分子筛比表面积、外比表面积、介孔孔容和平均孔径的增大,并调节了酸性质。但过长的处理时间并不利于介孔的生成和酸性的调变。经90℃的Na2CO3溶液处理5 h得到催化剂表现较高硫醚化活性,正丁硫醇和异戊二烯转化率分别可达92.36%和97.33%。由此,Na2CO3溶液处理可提高催化剂硫醚化活性,且改性过程温和可控。

ZSM-5 zeolites were treated by alkali Na2 CO3 solution;the effect of treatment temperature and time on the structural feature and physical and chemical properties of ZSM-5 zeolites were investigated.The ZSM-5 samples before and after alkali treatment were characterized by XRD, N2 sorption, XRF, SEM and NH3-TPD. With n-butyl mercaptan and isoprene as the model compounds for thioetherfication, the acit viyt of Ni-Mo/HZSM-5 prepared from alkali treated HZSM-5 ez olites with micro-and meso-porous strcu ture were evaluated. The results show that the original zeolite frame structure is rees rev da fter Na2C O3 solution treatment; moreover, the performance of the Ni-Mo/HZSM-5 catalyst in thioetherfications is improved and the modification process was gentel and controllable. An appropriate increase of the treatment temperature and treatment time w as beneficial to the incrae se of surface area, meso-pore volume and average pore size,a s well as ht e regulation of the acid properties without affecting the microporous structure.However, excessive long treatment time was disadvantageous to the formation of mesopores and the modulation of acidity.The Ni-Mo/HZSM-5 catalyst from ZSM-5 treated with Na2 CO3 solution at 90℃for 5 h exhibits high thioetherfication performance;the conversions of n-butyl mercaptan and isoprene reach 92 .36%and 97 .33%, respectively.