无胺体系高硅ZSM-5分子筛合成工艺的正交试验探索  

Process exploration of amine-free synthesis for high-silica ZSM-5 molecular sieves via orthogonal test

作　　者：柴超静 张瑞珍[1] 王毅林 李闻宇 赵亮富[2] CHAI Chaojing;ZHANG Ruizhen;WANG Yilin;LI Wenyu;ZHAO Liangfu(College of Materials Science and Engineering,Taiyuan University of Technology,Taiyuan 030024,Shanxi,China;Institute of Coal Chemistry,Chinese Academy of Sciences,Taiyuan 030001,Shanxi,China)

机构地区：[1]太原理工大学材料科学与工程学院,山西太原030024 [2]中国科学院山西煤炭化学研究所,山西太原030001

出　　处：《天然气化工—C1化学与化工》2022年第6期46-51,共6页Natural Gas Chemical Industry

基　　金：山西省应用基础研究计划(202103021224092);山西省高等学校教学改革创新项目(RC2200001789)。

摘　　要：在160℃水热条件下,选取硅铝比、碱硅比、水硅比、醇硅比(均为物质的量之比)和晶化时间5个合成参数作变量,通过设计5因素4水平的正交试验L_(16)(4^(5)),采用silicalite-1作为晶种,经无胺法制备了一系列ZSM-5分子筛。通过XRD表征考察了不同合成条件下产物的结构和相对结晶度,并结合产物产率筛选了无胺体系高结晶高硅ZSM-5分子筛的合成相区,最后通过SEM、NH-TPD和Py-IR等对其微观形貌和酸性进行了表征。结果表明,在160℃和较低水硅比(10~30)条件下,当投料硅铝比为50和100时,可在碱硅比0.050~0.125和醇硅比0.5~3.5较宽的合成相区制得高结晶度(>100.0%)、高产率(>74.0%)的纯相ZSM-5分子筛,但投料硅铝比为150和200时,合成相区较窄,不易制得高纯、高结晶ZSM-5分子筛。硅铝比为100的高结晶ZSM-5分子筛呈六棱柱状,具有典型的强酸性和B酸、L酸分布。A series of ZSM-5 molecular sieves were template-free synthesized at 160℃ with silicalite-1 as the seed via orthogonal experiments of five factors and four levels(L_(16)(4^(5))),where five synthetic parameters were taken as variables:silica-to-alumina ratio,alkali-to-silicon ratio,water-to-silica ratio,alcohol-to-silica ratio(all molar ratio)and crystallization time.The structure and relative crystallinity of the product under different synthetic conditions was investigated by XRD characterization,and synthetic phase region of high-silica ZSM-5 molecular sieves with high crystallinity in the amine-free system was screened together with the product yield.Finally,XRD,SEM,NH-TPD and Py-IR were used to characterize the structures and acidities of molecular sieves.The results show that high-silica ZSM-5 molecular sieves(the initial silica-to-alumina ratios are 50.0 and 100)with both high crystallinity(>100.0%)and high yield(>74.0%)can be synthesized within a wide synthetic phase zone(alkali-to-silica ratio of 0.050 to 0.125 and alcohol-tosilica ratio of 0.5 to 3.5)in the condition of 160℃ and low water-to-silica ratio of 10 to 30.However,when the initial silica-to-alumina ratios are 150 and 200,the synthetic phase zone is narrow,and it is difficult to prepare high purity and high crystallization ZSM-5 molecular sieves.The high crystalline ZSM-5 with a silica-to-alumina ratio of 100.0 has hexagonal prismatic configuration with a typical strong acidity and B acid and L acid distribution.

关 键 词：高硅ZSM-5分子筛 无胺合成 合成相区 正交试验 

分 类 号：TQ426.94[化学工程] O643[理学—物理化学]