苯甲醚在复合催化剂上的催化酰化

复合催化剂首次用于催化苯甲醚与酰化剂乙酰氯的酰化反应.发现不同沸石的单独使用仅给出很低产率的对-甲氧基苯乙酮.但是由HY沸石(硅铝比=40)或USY(超稳Y沸石)和SnO组成的复合催化剂的催化活性比单独使用沸石时高得多.增加由USY沸石和不同量的SnO组成的复合催化剂中的SnO的量,导致对-甲氧基苯乙酮产率的提高.由H型沸石(HY和H-ZSM-5沸石)和SnO组成的复合催化剂在苯甲醚与乙酰氯的酰化反应中的催化活性主要取决于所用沸石的硅铝比.     

用高浓度杂多酸溶液催化苯甲醚与乙酸酐的酰化反应

芳香化合物经Friedel-Crafts酰化反应制备药物和香料中间体芳香酮是近年来人们感兴趣的课题^[1-4]。用于该反应的传统催化剂是Lewis酸金属氯化物。由于反应过程中催化剂可与酰化试剂羧基产物形成配合物,因而催化剂用量大,且所形成的配合物水解后产生大量废液。为了减少环境污染,人们已成功地用分子筛催化剂代替传统催化剂催化芳香化合物的酰化反应^[5-7]。其中包括用分子筛催化各种芳香化合物与乙酸酐的酰化反应^[8]。我们已经研究了用杂多酸－乙酸浓溶液催化异丁烷与丁烯的烷基化反应^[9,10],以及烯烃与羧酸的直接酯化反应^[11]。本文将报道杂多酸－乙酸浓溶液对苯甲醚与乙酸酐酰化反应的催化活性。     

Hβ/MCM-41复合分子筛催化剂上苯甲醚与乙酸酐酰化反应研究

以β沸石为硅源,制备了不同硅铝比的Hβ/MCM-41复合分子筛,考察了该复合分子筛对苯甲醚与乙酸酐酰化反应的催化效果,并与介孔MCM-41、微孔Hβ分子筛的催化效果进行了比较,研究了分子筛硅铝比、酸性及孔道结构对酰化反应催化性能的影响。结果表明,对于苯甲醚和乙酸酐酰化反应,Hβ/MCM-41复合分子筛具有较好的催化稳定性,反应过程中的积炭量较少,积炭的碳氢比较低。该复合分子筛不仅具有微孔沸石的强酸性,而且具有较大孔径的介孔,产物分子能及时从孔道中扩散出来,催化活性位不易中毒失活。     

微波辐射改性ZnCl2—HY分子筛催化剂Ⅰ.在苯甲醚乙酰化反应中的催化性能

微波辐射改性ＺｎＣｌ２－ＨＹ分子筛催化剂Ⅰ．在苯甲醚乙酰化反应中的催化性能银董红尹笃林蒋汉瀛（湖南师范大学精细催化合成研究所长沙４１００８１）（中南工业大学冶金物理化学与新材料研究所长沙４１００８３）传统的Ｆｒｉｅｄｅｌ－Ｃｒａｆｔｓ酰化反应采用Ａｌ...     

Nafion功能化介孔催化剂上苯甲醚/苯甲酰氯酰基化反应研究

苯甲醚/苯甲酰氯的酰基化产物4-甲氧基二苯甲酮是多种精细化工产品的重要中间体. 本工作主要介绍了Nafion负载型SBA-15, SBA-16及Me-SBA-15介孔超强酸催化剂的制备及其在苯甲醚/苯甲酰氯酰基化反应中的应用. 实验结果表明, 单位时间单位Nafion活性位上的苯甲酰氯转化数高于传统HBeta沸石和硫酸氧化锆, 且载量的增加能显著提高酰基化催化性能. 甲基修饰的Me-SBA-15介孔材料明显改善了催化剂表面的疏水性能, 有效减缓了多聚芳烃副产物的生成, 反应的转化率得到大幅提高. 相对一维孔道结构的介孔SBA-15而言, 三维笼状结构的SBA-16对反应物及产物分子具有更好的扩散性能, 该结构优势由酰基化反应的高初始活性得以充分体现. 在整个反应过程中, 该类催化剂对4-甲氧基二苯甲酮具有专一的选择性.     

沸石催化的2,4,4-三甲基-1-戊烯的酰化反应

通过HY沸石与某些传统催化剂的比较，发现HY在2，4，4-三甲基-1-戊烯与乙酸酐的酰化反应中比那些传统催化剂更有效．用HY沸石作催化剂，室温下通过2，4，4-三甲基-1-戊烯与乙酸酐的酰化反应，合成了三种异构体，即4-（2，2-二甲基丙基）-4-戊烯-2-酮、（E）-4，6，6-三甲基-4-庚烯-2-酮和（Z）-4，6，6-三甲基-4-庚烯-2-酮．考察了HY沸石的用量对该酰化反应的影响．当2，4，4-三甲基-1-戊烯／乙酸酐／HY沸石=1mmol／10mmol／0．250g，反应温度25℃、反应时间2h时，生成的三种异构体产率之和为72％，HY沸石对于该反应具有极好的选择性和优良的活性稳定性，不同阳离子交换的Y沸石也用于催化2，4，4-三甲基-1-戊烯的酰化反应。     

2,4-二甲氧基苯甲酰氯的合成

2,4-二羟基苯甲酸与硫酸二甲酯经甲基化反应得到2,4-二甲氧基苯甲酸(3);3与SOCl2发生氯化反应合成了2,4-二甲氧基苯甲酰氯(4)。较佳的氯化反应条件为:325mmol,苯70mL,AlCl3250mg,回流反应1.5h,重结晶溶剂为石油醚(90℃～120℃),总产率达74.1%。2～4的结构经1HNMR和FT-IR表征。     

取代邻羟基二苯甲酮的合成1,3,5-三甲氧基苯与对位取代苯甲酰氯的Friedel-Crafts反应

控制反应物摩尔比、反应温度和反应时间，１，３，５－三甲氧基苯与对位取代苯甲酰氯发生Ｆｒｉｅｄｅｌ－Ｃｒａｆｔｓ反应，选择性地合成了２－羟基－４，６－二甲氧基－４－Ｒ－二苯甲酮和３－（４″－Ｒ－苯甲酰基）－２－羟基－４，６－二甲氧基－４－Ｒ－二苯甲酮。反应条件温和，产率较高。化合物的结构都经元素分析、１ＨＮＭＲ和ＩＲ确定。     

酸性沸石分子筛催化Knoevenagel缩合反应

 在高硅／铝比的酸性沸石分子筛HY上实现了Knoevenagel缩合反应．Bronsted酸和Lewis酸均可催化Knoevenagel缩合反应．考察了羰基化合物和活泼亚甲基化合物的反应活性顺序．结果表明，羰基化合物的羰基极化程度越高，反应越容易进行；不同于碱催化时的Knoevenagel缩合反应，活泼亚甲基化合物的活泼氢的酸性并不是影响其反应活性的重要因素．     

Regioselective Benzoylation of Glycopyranosides by Benzoyl Chloride in the Presence of MoO2(acac)2

Benzoylation of methyl and benzyl glycopyranosides by benzoyl chloride in the presence of MoO₂(acac)₂ as a catalyst resulted in 3-benzoates with good yield and high regioselectivity. Simple synthesis of the monobenzoates of some glycopyranosides is suggested.     

分子筛催化FCC混合C4烯烃液相水合反应

Methyl tert-butyl ether (MTBE) as an octane promoter in automobile fuels has been phased out in some countries due to environmental problems. This motivates substantial interest in finding new ways for upgrading gasoline[1,2]. The use of a replacement for MTBE, such as ethanol, is a feasible method to enhance the oxygenates and increase the octane number of gasoline[3].     

Acylation of Anisole Catalyzed by Hierarchical Porous Hβ Zeolite Modified with Cr

Modified hierarchical porous Hβ zeolite was obtained by metal modification of Hβ zeolite, which was treated with alkaline solution, and the catalysts before and after modification were characterized by means of X-ray diffraction(XRD), nitrogen adsorption-desorption, scanning electron microscopy(SEM), X-ray fluorescence(XRF), NH₃ temperature-programmed desorption and Fourier-transform infrared spectroscopy(FTIR). The activities of acylation of anisole with acetic anhydride were also investigated. The results show that the Hβ zeolite, which was treated with alkaline solution has microporous and mesoporous structures that could improve the diffusion performance of chemical reaction. The amount of acid was modulated with metal modification. The Hβ zeolite modified by 5%(mass fraction) metal chromium had the best catalytic performance. The conversion of acetic anhydride acylation was 93.01% under the optimal conditions, which was higher than that of other catalysts. The catalyst not only showed good activity, but also exhibited a stable performance in regeneration tests.     

Liquid - Phase Benzoylation of o -Xylene to 3,4-Dimethylbenzophenone Using Rare Earth Oxide Catalysts

The liquid phase benzoylation of o-xylene with benzoyl chloride over rare earth oxide catalysts like CeO₂ and Pr₂O₃ is studied in a batch reactor at atmospheric pressure and 411 K. Surface area, pore volume, acid strength distribution on the catalyst surface and optimum temperature of the catalyst are reported. This revised version was published online in June 2006 with corrections to the Cover Date.     

Brine-Mediated Efficient Benzoylation of Primary Amines and Amino Acids

Benzoylation of primary amines and amino acids is efficiently carried out in a brine solution using a stoichiometric amount of benzoyl chloride followed by trituration with aqueous saturated bicarbonate solution.     

Diffusion Mechanisms of Zeolite Catalysts

The diffusion mechanisms within zeolite catalysts, such as resistance to diffusion at pore mouths, configurational diffusion, adsorption-controlled diffusion, influence of co-existing molecules and pore blocking, were overviewed. Two kinds of diffusivities, the intracrystalline diffusivity and the effective diffusivity, were discussed separately to clarify the diffusion mechanism.     

Isomerization of n-Hexane Over Platinum Ion-Exchanged Zeolite Beta

Zeolite Beta was synthesized from appropriate gels and crystallized under the controlled temperature and pressurized conditions. For isomerization of n-hexane, platinum ion-exchanged zeolite Beta exhibited high activity and selectivity for 2,2-dimethylbutane (2,2-DMB), 2,3-dimethylbutane (2,3-DMB), 2-methylpentane (2-MP) and 3-methylpentane (3-MP). As high as 72% of n-hexane conversion and 98% of product selectivity were obtained at 250°C, 1600 h^–1 for 20 min on stream. The influences of reaction temperature and space velocity were also studied. Pt/H-Beta zeolite was recommended as one of the promising catalyst for n-hexane isomerization due to its high activity and stability. The combined effect of the stronger acidity possessed by H-Beta and the dehydrogenation role played by Pt was believed to be responsible for the good catalytic performance of Pt/H-Beta.     

用正电子湮没谱学研究氯化稀土在NaY沸石上的分散

用正电子湮没谱学研究氯化富铈稀土与NaY沸石机械混合形成的稀土NaY沸石(RE-NaY)中,氯化稀土在NaY中的分散．分别测量不同质量比的RE-NaY(1％-20％)经500℃烘烤1h,RE-NaY(5％)经过不同温度烘烤1h,以及RE-NaY(5％)经500℃烘烤不同时间后的正电子寿命谱．所有寿命谱都出现了5个寿命分量,其中第3,4,5寿命分别与β笼、超笼及沸石微粒界面空洞的大小和数量相关．实验表明了正电子湮没谱学能敏感地表征氯化稀土在NaY中的分散．     

分子筛催化剂上正十六烷的临氢异构化反应

 对分子筛催化剂上正十六烷的临氢异构化反应进行了研究，考察了不同分子筛催化剂的活性和选择性，并对临氢异构化反应的产物分布进行了分析．在此基础上，对正十六烷的临氢异构化反应机理进行了初步探讨．结果表明，正十六烷在中孔分子筛催化剂上的临氢异构化反应主要在分子筛外表面和孔口进行，分子筛的择形作用对异构选择性的影响有限．这与一般情况下低分子量正构烷烃在择形分子筛上的临氢异构化反应有所不同．临氢异构化反应的异构选择性主要取决于催化剂酸性组分的酸性质，弱酸和中等强度的酸对异构化反应有利，而催化剂的活性则由酸性组分中B酸中心的数量和加氢组分的活性共同决定．