EMT与β沸石的异丁烷／丁烯烷基化反应性能比较

异丁烷／丁烯烷基化反应是生产高辛烷值汽油的重要途径［‘j．目前,工业生产烷基化汽油使用HF或H。SO。作为催化剂,存在严重的环保和安全问题．用固体酸催化剂替代液体酸的研究已有30多年历史．90年代初,一种新型六方相八面沸石（现称为EMT）被合成出来［‘j,这种沸石是具有两维交叉直孔道体系的大孔沸石［’‘,且其H型结构具有强酸性“’,因而很快受到人们的重视．St6cker等人‘’‘使用半批量式反应器的研究表明,HEMT是一种优良的异丁烷／丁烯烷基化催化剂．另外,Corma等人＊‘使用固定床反应器的研究表明,HS沸石对该烷基…     

异丁烷-丁烯烷基化反应催化剂的研究

固体强酸;异丁烷-丁烯烷基化反应催化剂的研究     

六方沸石分子筛催化剂用于异丁烷与丁烯的烷基化

异构烷烃与烯烃的烷基化是炼油装置制备高辛烷值汽油添加剂的重要途径.目前传统工艺仍使用矿物酸如硫酸或氢氟酸作催化剂,由于该工艺存在着产物分离困难、设备腐蚀严重及环境污染问题,从60年代起国内外开始致力于新型固体酸催化剂的研究与开发工作,已报道的有离子交换树脂[1]、分子筛催化剂[2]及SO=4/MxOy型催化剂[3]等,在分子筛催化剂中已报道的有立方沸石[4]β-分子筛[5]、ZSM系列[5]、分子筛[5]、蒙脱石[5]及MCM-22[6]等,这些催化剂的共性是催化活性较高,但失活较快.目前对分子筛催化剂的研究主要集中在改进的立方沸石体系,而六方沸石催化剂催化异丁烷与丁烯烷基化反应尚未见报道.     

WO3／ZrO2固体强酸催化剂上异丁烷—丁烯烷基化反应的研究：Ⅲ.超 …

制备了以超细ＺrＯ２为载体的ＷＯ３／ＺrＯ２、ＳＯ４＾２－／ＺrＯ２、ＭoＯ３／Ｚr Ｏ２固体强酸催化剂,并用ＸＲＤ、ＤＴＡ－ＴＧ、Ｈ２－ＴＰＲ、ＮＨ３－ＴＰＤ等方法表征了其晶型结构、表面状态和酸性。结果表明,超细ＺrＯ２中的Ｔ－晶相所占比例虽有所下降,但具有更大的比表面积、酸强度和对金属氧化物的负载能力,且酸强度随焙烧温度升高而增强,表明其表面状态亦有较大变化。研究了以超细ＺrＯ２为载体的固体强酸催化     

固体超强酸在异丁烷/丁烯烷基化反应中的再生研究

催化剂再生对于固体酸异丁烷／丁烯烷基化反应是必需的．虽然Broensted-Lewis共轭固体超强酸在温和条件下即对异丁烷／丁烯烷基化反应有良好的反应活性，但它仍象其它所有固体酸催化剂一样，面临着失活的问题．最主要的失活原因是积炭前身物生成并在催化剂表面的沉积，导致催化剂表面活性中心被覆盖．据此进行的再生方法研究集中在消除这些积炭前身物，本文中选择使用的是洗涤再生法，结果表明该方法对于该固体超强酸的再生在一定程度上是有效的。     

异丁烷-丁烯烷基化反应催化剂的研究

制备了一系列不同焙烧温度的Ｚｒ（ＳＯ４）２及Ｚｒ（ＳＯ４）２负载量不同的Ｚｒ（ＳＯ４）２／Ａｌ２Ｏ３（ＳｉＯ２）固体强酸催化剂,用ＸＲＤ、ＩＲ、ＢＥＴ、ＴＧ－ＤＴＡ、ＮＨ３－ＴＰＤ、Ｈａｍｍｅｔｔ指示剂等方法研究了该催化体系的晶型、结构、比表面、酸量及酸强度随负载量和焙烧温度的变化规律。将Ｚｒ（ＳＯ４）２负载在Ａｌ２Ｏ３和ＳｉＯ２两种载体上呈现不同的特性。在Ａｌ２Ｏ３上明显地延缓了Ｚｒ（ＳＯ４）２     

异丁烷与丁烯烷基化反应的热力学分析

对异丁烷与丁烯烷基化反应进行了较为详尽的热力学分析和计算,得到了不同反应温度下的焓值、吉布斯自由能和反应平衡常数,并且对温度、压力和惰性物质对热力学平衡的影响进行了分析。得到了详细的烷基化反应热力学基础数据,这些数据对研究异丁烷与丁烯的烷基化反应具有重要的参考价值。     

HEMT沸石负载12-钨硅酸对异丁烷与丁烯烷基化反应的催化性能

 在压力为2．0MPa的连续流动液相反应系统中,考察了HEMT负载12－钨硅酸催化剂对异丁烷与丁烯烷基化反应的催化性能,并与HEMT沸石及12－钨硅酸催化剂进行了比较．采用差热分析、比表面积测定、红外光谱及程序升温脱附等方法对催化剂进行了表征．发现HEMT负载12－钨硅酸后,催化剂的稳定性及对烷基化反应的催化活性和选择性有了明显提高,其中高辛烷值的目的产物三甲基戊烷的选择性较HEMT提高了17．6％．讨论了催化剂的酸性与烷基化反应活性的关系．     

Coke precursor as an intermediate during the alkylation of isobutane/butene over a solid superacid

Alkylation of isobutane/butene was conducted on a Brønsted-Lewis conjugated solid superacid. It is found that some hydrocarbons accumulated on the catalyst surface. These hydrocarbons, as called coke precursor, played an intermediate role at the initial stage of the alkylation before they lead the catalyst to lose its activity. The presence of the intermediate is beneficial to the alkylation between isobutane and butene, while increase the TMP content and TMP/DMH ratio in the products     

Development of mesoporous ZSM-12 zeolite and its application in alkylation of 2-methylnaphthalene

Desilicated MTW zeolite was evaluated in methylation of 2-methylnaphthalene (2-MN) in a fixed-bed flow reactor at 450 °C. Mesoporous MTW was fabricated via a microwave-assisted desilication process using a harsh alkaline solution to improve the pore volume and the surface area. H-ZSM-12 zeolite was treated with 0.3 M of NaOH solution with different treatment times. Due to the harsh alkaline treatment, micropores were blocked by the deposition of the removed atoms. Due to the importance of methylnaphthalenes intermediates, modified MTW zeolites were evaluated in methylation of 2-MN. Methanol (MeOH), 2-MN and 1,3,5-trimethylbenzene (TMB) were fed to the reactor with a molar ratio of 15:15:70. Higher selectivity to 1-methylnaphthalene (1-MN) was observed rather than dimethylnaphthalene and trimethylnaphthalene with a yield of 13.6, 8 and 2.5 mol%, respectively. Moderate conversion up to 24.1 mol% was reached for 30 min reaction.     

Hydrothermal synthesis of Al- and Ga-substituted Omega zeolite

The synthesis and characterisation of zeolite Al- and Ga-Omega has been studied in the temperature range 383–413 K using tetramethyl ammonium hydroxide as a template. The evidence for framework gallium substitution was obtained from chemical analysis, X-ray diffraction, IR, solid state MAS NMR, thermoanalytical studies and ion exchange. Crystal morphology varied with the degree of isomorphous substitution of both Al and Ga and the synthesis temperature.     

高浓度杂多酸溶液催化性能的研究1: 一种新型异丁烷/丁烯烷 基化催化剂

在异丁烷、丁烯烷基化反应中研究了一种由杂多酸和醋酸组成的新型液体催化剂的催化性能,醋酸作为溶剂对杂多酸具有共协效应,系统研究了形成活性相的条件,杂多酸结晶水含量对活性相的形成和催化活性均有显著影响,这一催化体系具有与硫酸可比的催化活性。     

高浓度杂多酸溶液催化性能的研究1: 一种新型异丁烷/丁烯烷 基化催化剂

在异丁烷、丁烯烷基化反应中研究了一种由杂多酸和醋酸组成的新型液体催化剂的催化性能,醋酸作为溶剂对杂多酸具有共协效应,系统研究了形成活性相的条件,杂多酸结晶水含量对活性相的形成和催化活性均有显著影响,这一催化体系具有与硫酸可比的催化活性。     

Adsorption of isobutane on H-TsVM zeolite

A procedure was developed for evaluating the adsorption of hydrocarbons on solids by monitoring the temperature of the gas over the sample layer and inside it, the heat conductivity of the gas at the inlet and outlet of the flow reactor, and the composition of the gas after the sample. The adsorption-desorption of isobutane accompanied by heat liberation or absorption (recorded as a temperature change in the zeolite layer) was studied using the H-TsVM zeolite as an example. The temperature effects during isobutane adsorption and desorption were compared. It was concluded that below ～90°C, some part of isobutane is significantly chemisorbed on H-TsVM. The highly adsorbed isobutane can be removed by keeping the sample in a nitrogen flow for a long time or by heating it above 90°C. Time dependence of isobutane desorption at constant temperature can be described by first order kinetic equation, making possible to estimate the activation energy of desorption of highly chemisorbed isobutane using the data on thermodesorption at linear temperature increase.     

Distribution of the products from the alkylation of isobutane with butenes at a zeolite catalyst and the reaction mechanism

The mechanisms of formation are proposed on the basis of the distribution of the intermediate and final products of zeolite alkylation of isobutane with butenes. The mechanisms are based on activation of the isobutane molecule at the methyl groups, simultaneous intermolecular and intramolecular hydride transfer, and β dissociation during skeletal isomerization of the carbonium ions.     

tert-Butanesulfinylthioether ligands: synthesis and application in palladium-catalyzed asymmetric allylic alkylation

A class of novel chiral SO-S-type bidentate ligands based on the tert-butylsulfinyl moiety as the sole chiral source were designed and synthesized through a simple and efficient pathway. These ligands are effective catalyst precursors for the palladium-catalyzed allylic alkylation of 1,3-diphenyl-2-propenyl acetate and moderate to good stereoselectivities (up to 84% ee) were obtained.