苯丙苯基化β沸石催化剂上沉积物的组成和性质

 改性β沸石是高压液相苯－丙烯异丙基化合成异丙苯反应的优良催化剂,具有催化活性高和选择性高及稳定性好等优点,已成功进行了中试．用13CNMR,IR,GC－MS,TG等手段,并结合溶剂萃取法、TPO和结构分析等方法,确定了改性β沸石催化剂上沉积物的主要成分是多异丙基苯和四氢化萘,且主要分布在沸石孔道内;同时,快速升温后恒温烧炭的效果优于慢速升温后恒温烧炭的效果．     

煤焦油萘择形异丙基化产物组成的气相色谱/质谱分析

 采用毛细管气相色谱 /质谱 (CGC/MS)联用技术 ,经计算机质谱库检索并结合人工谱图解析 ,研究了在不同沸石分子筛催化剂上煤焦油萘择形异丙基化产物的组成。研究结果表明 ,煤焦油萘异丙基化产物主要由一取代萘、二取代萘以及少量三取代萘组成 ;除 HZSM-5活性较低以外 ,其它催化剂均有较高的反应活性 ,其中 HY和 Hβ反应活性最高 ,萘转化率分别达 75 .1 5 %和 5 5 .96% ,但β位产物的选择性较差 ;ZM类催化剂既有一定的活性 ,又有较高的β选择性 ,是萘择形异丙基化反应理想的备选催化剂。     

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.     

Isopropylation of benzene with 2-propanol over substituted large pore aluminophosphate-based molecular sieves

Large pore aluminophosphate-based molecular sieves like AlPO₄-5, MAPO-5, MnAPO-5 and ZAPO-5 were synthesised hydrothermally using triethylamine as a structure directing agent. These materials were characterised by X-ray diffraction (XRD),²⁷A1 and³¹P MAS-NMR, ICP-MS,n-butylamine-TPD, BET and SEM. The catalytic performance of these materials was tested for isopropylation of benzene with 2-propanol at 250, 300, 350 and 400°C. The products were cumene,p-DIPB (p-diisopropylbenzene) andm-DIPB (m-diisopropylbenzene). MnAPO-5 was found to be more active than the other catalysts. Maximum conversion (20%) was noted at 350°C over MnAPO-5. The selectivity to DIPB was found to decrease with time on stream but the selectivity to cumene showed an increase after 3 h of time on stream     

Surface chemical modification of zeolites and their catalytic performance for naphthalene alkylation

Acid-catalyzed naphthalene alkylation products, such as 2,6-dialkylnaphthalenes (2,6-DAN), are industrially important compounds used to make monomers for advanced polymer materials [1]. Zeolite molecular sieves can be extensively used in many catalytic applications, specifically in naphthalene alkylations due to their high activity and stability as well as their high selectivity. The initial studies have mainly focused on gas phase alkylation of naphthalene with methanol, and only obtained th…     

Unsteady state behavior of CO oxidation over a supported Pt catalyst in the millibar range

The alkylation of naphthalene with isopropanol was investigated over a HY (Si/Al=4) zeolite under the following conditions: flow reactor, liquid phase with decalin as solvent, 623 K, 40 bar. Despite complete filling of the zeolite pores by coke during the first hour of reaction, the rate of formation of isopropylnaphthalene remained very high. This is due to the development of a new reaction process involving transalkylation between the polyisopropyl naphthalenes entrapped in the pores and naphthalene followed by the realkylation of the former compounds with isopropanol.     

沸石分子筛催化剂上萘的择形异丙基化反应性能

 研究了HY,Hβ,HM和HZSM－5沸石分子筛对萘择形异丙基化反应的催化性能．结果发现,这些沸石分子筛的活性顺序为HY＞Hβ＞HM＞HZSM－5,对2,6－二异丙基萘的选择性顺序为HM＞Hβ＞HY．除沸石分子筛的酸量与酸分布外,其孔道结构与大小是影响萘异丙基化反应的主要因素．脱铝能选择性地降低沸石外表面的酸性,且对沸石的催化性能有较大影响．常压水蒸气脱铝结合强酸再处理有利于催化剂催化性能的提高．提高反应温度有利于萘的转化,但温度过高会引发许多副反应,适宜的反应温度约为523K．反应时间对产物分布的影响不明显．异丙醇／萘摩尔比应小于2．