Herein, we prepared a series of H-Zn-mordenite (H-Zn-MOR) catalysts by adding zinc source into the initial sols during the synthesis of mordenite (MOR). The results indicated that isolated Zn ions were highly disperse...Herein, we prepared a series of H-Zn-mordenite (H-Zn-MOR) catalysts by adding zinc source into the initial sols during the synthesis of mordenite (MOR). The results indicated that isolated Zn ions were highly dispersed in the catalysts. The addition of zinc led to the increase of Si/Al in the framework of MOR,the change of the distribution of acid sites and the change of acid strength. We investigated the catalytic performance of the H-Zn-MOR catalysts and the HMOR catalysts for carbonylation of dimethyl ether to methyl acetate. The addition of zinc improved the catalytic performance and made the drop of the conversion over the Zn-0.003 and Zn-0.005 catalysts to be about the half of that over the HMOR catalyst.We attributed it to the change of the acid properties, which further change the rate of coke deposition.展开更多
在水热合成体系中,以三乙胺(TEA)和四乙基氢氧化铵(TEAOH)为混合模板剂,考察了在初始凝胶形成过程中铝源的加入方式对合成SAPO-34分子筛及甲醇制烯烃(MTO)催化性能的影响;通过X射线衍射(XRD)、扫描电子显微镜(SEM)、氮气等温吸附脱附(B...在水热合成体系中,以三乙胺(TEA)和四乙基氢氧化铵(TEAOH)为混合模板剂,考察了在初始凝胶形成过程中铝源的加入方式对合成SAPO-34分子筛及甲醇制烯烃(MTO)催化性能的影响;通过X射线衍射(XRD)、扫描电子显微镜(SEM)、氮气等温吸附脱附(BET)、^(29)Si固体核磁(^(29)Si MAS NMR)、氨气程序升温脱附(NH_3-TPD)等方法对合成产物进行物性表征,并研究了其在甲醇转化制烯烃(MTO)反应中的催化性能。结果表明,随着首先加铝量的增加,粒径有逐渐变小的趋势,且逐渐出现板层状形貌的SAPO-34分子筛;同时,产物分子筛骨架中Si(4Al)配位结构的数量增加,强酸比例在逐渐增大,且酸密度增加;随着强酸比例和酸密度的提高,SAPO-34分子筛在MTO催化反应中的寿命逐渐延长,丙烯选择性逐渐增大而乙烯选择性逐渐减小。展开更多
基金supported by the National Natural Science Foundation of China (Nos. 21476159, 21676182)the 973 Program (No.2014CB932403)authors are also grateful to the Program of Introducing Talents of Disciplines to China Universities(No. B06006)
文摘Herein, we prepared a series of H-Zn-mordenite (H-Zn-MOR) catalysts by adding zinc source into the initial sols during the synthesis of mordenite (MOR). The results indicated that isolated Zn ions were highly dispersed in the catalysts. The addition of zinc led to the increase of Si/Al in the framework of MOR,the change of the distribution of acid sites and the change of acid strength. We investigated the catalytic performance of the H-Zn-MOR catalysts and the HMOR catalysts for carbonylation of dimethyl ether to methyl acetate. The addition of zinc improved the catalytic performance and made the drop of the conversion over the Zn-0.003 and Zn-0.005 catalysts to be about the half of that over the HMOR catalyst.We attributed it to the change of the acid properties, which further change the rate of coke deposition.
文摘在水热合成体系中,以三乙胺(TEA)和四乙基氢氧化铵(TEAOH)为混合模板剂,考察了在初始凝胶形成过程中铝源的加入方式对合成SAPO-34分子筛及甲醇制烯烃(MTO)催化性能的影响;通过X射线衍射(XRD)、扫描电子显微镜(SEM)、氮气等温吸附脱附(BET)、^(29)Si固体核磁(^(29)Si MAS NMR)、氨气程序升温脱附(NH_3-TPD)等方法对合成产物进行物性表征,并研究了其在甲醇转化制烯烃(MTO)反应中的催化性能。结果表明,随着首先加铝量的增加,粒径有逐渐变小的趋势,且逐渐出现板层状形貌的SAPO-34分子筛;同时,产物分子筛骨架中Si(4Al)配位结构的数量增加,强酸比例在逐渐增大,且酸密度增加;随着强酸比例和酸密度的提高,SAPO-34分子筛在MTO催化反应中的寿命逐渐延长,丙烯选择性逐渐增大而乙烯选择性逐渐减小。
