β沸石催化邻苯二酚-叔丁醇烷基化反应

 考察了Hβ沸石及改性Hβ／Al2O3对邻苯二酚－叔丁醇烷基化反\r\n应的催化性能，并采用XRD和NH3－TPD方法表征了Hβ沸石及改性Hβ／\r\nAl2O3的酸性和结构特性，讨论了其酸性对催化活性及选择性的影响．\r\n结果表明，Hβ沸石和Co改性的Hβ／Al2O3的催化性能都优于目前文献\r\n报道的最好水平，对催化邻苯二酚－叔丁醇烷基化反应具有良好应用开\r\n发前景．     

改性X型沸石催化甲苯、甲醇侧链烷基化反应的研究进展

综述了三十年来国内外有关在改性Ｘ型沸石催化剂上,甲苯、甲醇侧链烷基化制备苯乙烯反应的研究状况。经过性改性的Ｘ型沸石具有合适的孔径和适当强度及数量的表面酸碱中心、表面酸碱中心的协同作用有利于反应活性及选择性的提高。参考文献１２６篇。     

MCM－22沸石的孔结构和酸分布特性对苯与丙烯烷基化反应产物分布的影响

 根据测试结果，得到了MCM－22和具有相同硅铝比的β沸石的酸中心数及其分布，系统地研究了反应条件对苯与丙烯烷基化反应产物分布的影响；结合扩散系数与扩散势能，讨论了产物分布与MCM－22沸石孔道及酸性质的关系，并与β沸石进行了比较．苯烷基化反应发生在MCM－22沸石的外表面上，其空间位阻较小；在相同的反应条件下，与发生在β沸石十二元环孔道内的苯烷基化反应相比，异丙苯的选择性低2％～4％，二异丙苯的选择性高0．5％～5％，三异丙苯的生成量多10余倍．位于MCM－22沸石十元环二维正弦波形孔道的B酸中心，由于空间位阻大，很难发生苯烷基化反应，但可发生丙烯齐聚反应，故MCM－22沸石上有较多的丙烯齐聚物生成．β沸石上生成正丙苯的量是MCM－22沸石上的3～4倍．     

β沸石在丙烯醚化反应中的催化性能

研究了β沸石在不同焙烧温度和加入粘合剂条件下对丙烯与异丙醇合成异丙醚的催化性能。并通过ＸＲＤ、ＸＰＳ、ＮＨ３－ＴＰＤ、ＦＴ－ＩＲ及化学吸附等手段表征了β沸石的物理化学性质。结果表明：焙烧对丙烯醚化反应存在一合适的温度范围；Ａｌ２Ｏ３粘合剂提高了丙烯转化率，降低了异丙醇脱水活性；粘合剂使沸石表面上Ｌ酸中心的比例增加；丙烯醚化反应与Ｌ酸中心存在较好的对应关系，而异丙醇脱水反应与Ｂ酸中心对应；高温焙烧β沸石使骨架铝向表面迁移，粘合剂Ａｌ２Ｏ３能抑制沸石的晶胞收缩。     

Shape-Selective Alkylation of Isopropylnaphthalene over HM Zeolite. A Theoretical Study

A first principle quantum chemical method for determining the shape of molecules has been elaborated and its value in interpreting the experimentally found shape selectivity in isopropylation of isopropylnaphthalene on H-mordenite zeolite is demonstrated. In line with experimental results, it is found that 2,6-diisopropylnaphthalene is the most feasible product since it diffuses through the main channels of mordenite the easiest among the possible isomers.     

改性纳米HZSM-5催化剂上甲苯与甲醇的烷基化反应

以Si,P,Mg复合改性的纳米HZSM-5为催化剂,进行了甲苯与甲醇的烷基化反应;并采用X射线衍射,NH3程序升温脱附,红外和低温N2吸附等方法研究了改性前后催化剂酸性质和孔结构的变化.在小型固定床反应器上,考察了载气量、反应温度和重时空速等反应条件对烷基化反应性能的影响.在2h-1,460℃,甲苯/甲醇比,水/烃比和...     

SiO_2改性MCM-22分子筛上联苯与环己醇的择形烷基化反应

以正硅酸四乙酯(TEOS)为修饰剂,采用化学液相沉积法(CLD)对MCM-22分子筛进行改性,制备了一系列SiO_2改性的MCM-22催化剂。采用X射线衍射(XRD)、N_2物理吸附-脱附、氨程序升温脱附(NH_3-TPD)、吡啶吸附红外光谱(Py-IR)对催化剂性质进行了表征。结果表明SiO_2主要沉积在MCM-22分子筛的外表面,外表面上的Br?nsted酸位量明显减少,但对分子筛的总酸量影响不大。考察了改性催化剂用于联苯与环己醇的择形烷基化反应制备线性4-环己基联苯(4-CBP)及4,4′-环己基联苯(4,4′-DCBP)的催化性能。在常压条件下,温度为190°C时反应200 min,4-CBP与4,4′-DCBP的选择性分别为80.4%与63.7%。结合表征数据,发现SiO_2沉积对发生在催化剂外表面Br?nsted酸位上的异构化反应有明显的抑制作用。此外,重复使用5次后的改性分子筛经过焙烧复原,活性与选择性基本恢复。     

Comparative Evaluation of Zeolite Catalysts of Benzene Alkylation

Using the benzene alkylation reaction with propylene, the catalytic properties of heterogeneous catalysts are compared under conditions of simultaneous action of permanent deactivating factors (atmospheric pressure, increased volume feed rate) on the samples under study. For a comparative evaluation of the tested catalysts, a mathematical analysis of the experimental data on the concentration of the desired alkylation product vs. the time of the catalyst operation was carried out, and a corresponding empirical formula was derived. To compare the activity of catalysts, the power coefficient of the function was proposed as a catalyst activity factor f. A relationship between the value of this factor and the rate of deactivation of the catalyst under the conditions of the experiments was derived.     

USY分子筛催化FCC汽油的烷基化脱硫反应研究

以USY分子筛催化FCC汽油中噻吩类硫化物与烯烃的烷基化反应,采用DL-2B-EE微库仑仪测定反应前后硫分布的变化,考察了USY分子筛的制备条件和烷基化反应温度对其催化性能的影响.实验结果表明,水蒸汽处理温度350℃、水蒸汽处理时间5h,反应温度120℃时,USY分子筛催化剂的比表面积为613m2/g,催化活性最佳,使得FCC汽油中<100℃馏分的硫含量减少至16.92mg/L.水蒸汽流速对USY分子筛催化烷基化反应影响不大.不同处理方法所得USY分子筛的吡啶吸附红外光谱结果表明,具有较多的酸中心的USY分子筛更有利于催化FCC汽油的烷基化脱硫反应.     

改性的纳米HZSM-5沸石作为对位选择性烷基化反应催化剂

Zeolites with grain size less than 100 nm, which bear both the unique physical properties of nano grains and the unique micropore character of zeo lites, are big potentials in replacing the existing zeo lite catalysts and in developing novel environmental ly-benign catalytic processes. We observed[1] in the alkylation of ethylbenzene with ethylene that the at tenuation of the HZSM-5 crystallites into nano-size significantly increases the catalyst activity and dura bility. Yet studies on the modification of nano-zeo lites in order to improve their low shape-selectivity remain unreported.     

Mechanism of the Alkylation of Isobutane by Butenes on Zeolite Catalysts

A key role has been proposed for primary carbocations in the initial and final steps of the alkylation of isobutane by butenes on zeolites. Secondary and tertiary carbocations play a role predominantly in steps involving intramolecular transformations.     

MCM-49分子筛的合成及其对烷基化反应的催化性能

The MCM 49 zeolite was successfully synthesized using an organic mixture solution (OMS) yielded from hydrogenation of caprolactam as the template instead of the pure hexamethyleneimine (HMI). The OMS contains HMI (76 0%～84 0%), caprolactam (1 0%～10 0%), water, and a few by products. So the synthesis cost of the MCM 49 zeolite decreases obviously. The MCM 49 zeolite synthesized using OMS as the template shows similar crystallinity and purity to that synthesized using pure HMI in conventional process. From the results of NH 3 TPD, N 2 adsorption isotherm, and DTA, it is evident that the MCM 49 zeolite possesses three kinds of acidic centers with different strength, and has a high specific surface area and good thermostability. Furthermore, the MCM 49 zeolite shows good catalytic behavior for the alkylation of benzene with dilute ethylene to ethylbenzene.