凹凸棒土固载N-杂环卡宾催化安息香缩合反应

本文将五种不同的NHCs催化剂前体接枝到凹凸棒土表面，制备了五种负载型NHCs催化剂。通过FT-IR、元素分析、BET和SEM对五种催化剂进行了表征，表征结果表明NHCs催化剂前体成功地固定在凹凸棒土表面。进一步的实验结果表明，这些负载型NHC可以作为安息香反应的有效催化剂。接着探究了这些负载型催化剂催化安息香反应的优化条件。结果发现，当BTBCl@ATP(催化剂B, 1 mmol%咪唑盐)作为催化剂，0.4当量NaOH作为碱，2ml CH3OH作为溶剂，在110℃油浴中，在Ar气氛中反应8小时，收率最高。在此优化条件下，负载型NHCs催化剂可以催化多种芳香醛的安息香反应，产率为61-86%。催化剂的重复使用实验表明，这些负载型催化剂可以简单地从反应体系中分离出来，重复使用四次后，这些负载型催化剂的催化活性没有明显下降。     

丁烯烷基化固体酸催化剂的研究进展

阐述了异丁烷 丁烯烷基化催化剂的发展状况,主要涉及了几种新型固体酸催化剂,包括固体超强酸催化剂、分子筛催化剂和负载型杂多酸催化剂。文章着重对SO2-4 MxOy、MCM-41和负载型杂多酸催化剂的制备,活性和选择性作了探讨。同时指出了这些固体酸催化剂存在的问题,预测了烷基化催化剂研究的发展方向。     

聚酯催化剂的研究进展

详细叙述了锑系、钛系、锗系、锡系、铝系和酶催化剂在聚酯反应中的应用情况,介绍了这些催化剂的分类和它们的优、缺点,指出高效环保型催化剂是聚酯催化剂发展的方向。     

甲醇合成催化剂使用效果的影响因素及对策

介绍了甲醇合成催化剂的制造及使用过程,探讨了催化剂的失活方式及其机理,提出防止或消除这些因素、延长甲醇合成催化剂寿命的方法。     

几种过渡金属催化剂应用于乙烯的聚合

介绍了高分子聚合用的Ziegler-Natta催化剂、Philips催化剂以及茂金属催化剂的结构特点及聚合性能比较,论述了这些催化剂在乙烯聚合中的应用与发展以及所生成的聚乙烯的结构与性能。     

Ni/CeGdO催化甘油水蒸气重整(SRG)制氢

采用浸渍法制备了Ni/Ce_xGd_(1-x)O_y(x=0.1、0.5、0.9)系列催化剂,用N_2物理吸附、X-射线衍射、H_2程序升温还原、H_2脉冲化学吸附和程序升温氧化等技术表征了这些催化剂的结构和性质,并考察了这些催化剂催化甘油水蒸气重整制氢的反应性能。结果表明:这些催化剂均表现了良好的活性,载体中Ce/Gd的不同摩尔比能够影响催化剂活性,当铈钆比达到9∶1,催化剂催化效果达到最佳。通过分析反应温度对催化剂稳定性、产物选择性、甘油转化率产生的影响,发现500℃时,Ni/Ce_(0.9)Gd_(0.1)O_(1.95)催化剂上甘油转化率可达到96.5%,10 h的反应表现了良好的稳定性,产物选择性基本不变。     

一水合硫酸氢钠催化合成柠檬酸三丁酯

传统的柠檬酸三丁酯（TBC）合成工艺是采用浓硫酸、对甲苯磺酸等强酸性催化剂，这些工艺存在着副反应严重、产品质量差、设备腐蚀和环境污染严重的缺点。近几年也曾有一些合成TBC的新型催化剂如固体酸、固体超强酸等的报道，这些催化剂催化活性高，效果好，有效克服了强酸性催化剂的不足。但这些催化剂的制备工艺较复杂，价格昂贵。长江大学化学与环境工艺学院于兵川，吴洪特对以一水合硫酸氢纳为催化剂合成TBC进行了工艺探讨，发现一水合硫酸氢钠是一种性能优良的合成TBC的催化剂，除有效克服了强酸性催化剂的不足外，还具有价格便宜，易得，可重复使用等优点。     

浅析氨合成催化剂还原

泸天化合成二车间2004年技改对合成催化剂进行了更换,催化剂的还原是催化剂更换的一个重要环节,温度、压力、空速都是影响催化剂还原的重要因素,实现还原过程中这些参数的调整都要根据出塔水汽浓度进行。     

苯酚羟基化反应催化剂研究进展

对近年来苯酚双氧水羟基化反应的催化剂进行了综述。目前研制开发的性能优良的催化剂主要有:复合金属氧化物、杂原子取代的分子筛及杂多酸盐等,详细介绍了这些催化剂的性能及特点。     

油品精制催化剂技术进展

描述了工业油品精制催化剂开发过程中所应考虑的六大要素,讨论了这些要素对催化剂性能提高的影响:包括通过各种技术调节手段,如无机助剂改性、有机助剂改性、超声辅助手段等实现对催化剂的理化性质调控,如改善酸性质、比表面积、孔结构、堆积密度等;通过这些技术手段还可调变金属-载体相互作用、活性金属的分散度和硫化度、MoS₂(WS₂)片晶长度和叠层数等,实现对催化活性中心形貌的控制;通过原材料选取及生产过程优化,降低催化剂成本;通过催化剂形态合理设计,提高催化剂体系的活性及稳定性。介绍了在工业油品精制催化剂技术进步中一些技术调节手段的应用,给出了系列商品催化剂活性进步的历程,并指出了提高催化剂性能的一些新思路,最后介绍了一些新的材料及方法在油品精制上的应用。     

D-葡萄糖五乙酸酯的催化合成研究进展

D-葡萄糖五乙酸酯是非常重要的糖类衍生物,在二氧化碳吸附、医药、精细化工和石油化工等领域用途广泛,关于D-葡萄糖五乙酸酯的合成、产物构型转化与控制是其热点研究方向。本文综述了D-葡萄糖五乙酸酯的催化合成研究进展,主要介绍了均相催化、固体酸催化、酶催化等方法合成D-葡萄糖五乙酸酯的研究情况,重点叙述了吡啶和乙酸钠等碱性催化剂、质子酸和路易斯酸等酸性催化剂、沸石分子筛和杂多酸等固体酸催化剂在D-葡萄糖五乙酸酯合成中的应用情况,指出开发催化活性高、选择性高、构型可调控的催化剂,并将其用于糖类化合物的酯化反应是未来重点研究的方向。     

Supported solid and heteropoly acid catalysts for production of biodiesel

Biodiesel has developed attraction of most researchers recently because of its renewable resources and environmental benefits. Transesterification process in the presence of catalysts is the most common way, which is used for biodiesel production. Heterogeneous acid catalysts are considered more reliable than any other catalysts to carry out most vital reactions related to green chemistry (biodiesel production), because the production of biodiesel from solid acid catalysts is considered economically favorable. Nowadays, biodiesel is preparing from low quality feedstock by using solid acids catalysts in many research laboratory throughout the world. This article discusses how much catalyst shapes affect the efficiency of catalyst during catalysis. Different types of supports (zinc oxide, alumina, zirconia, and silica) are used to increase the efficiency of catalysts. Supported Lewis acid, Brønsted acid, and heteropoly acid catalysts show good efficiency for the catalytic transesterification of oil with alcohol. Heteropoly acid catalysts are tremendous and environment friendly acid catalyst and have ability to tolerate contaminations of oil resources such as water contents and free fatty acids (FFAs) contents. Keggin-type heteropoly acids are easily available and having stable structure while Wells–Dawson-type heteropoly acids are included in super acid class, due to these reasons heteropoly acids are considered as best acidic catalysts for biodiesel production by catalytic transesterification process. Therefore, this review also focused on the deactivation, regeneration and advantages of supported solid acid catalysts used for the catalytic production of biodiesel through transesterification.     

固体酸催化剂的分子设计初探

高效固体酸催化剂无论对现有工业生产还是从环保考虑都是十分需要的。鉴于均相和多相酸催化剂的活性部位有诸多共同特点(化学性质和对反应机理以及控制步骤速度的影响),根据现代均相酸催化理论,以Bronsted酸和Lewis酸为例,广泛讨论了类似活性部位的异同,探讨了活性部位在均相和多相酸催化反应中结构和机理上的类似性以及固体晶格在形成固体酸催化剂活性部位时的特殊作用,并对阳碳机理作了评价,最后对固体酸催化剂的设计提出了建议。     

不同沸石催化剂上苯与1-十二烯烷基化

利用NH3 TPD测定了 4种沸石分子筛的酸性 ,并考察了 4种分子筛在苯与 1-十二烯烷基化反应中的催化性能 ,揭示了沸石分子筛的酸性、孔结构对其催化活性和产物选择性的作用规律 ,发现沸石分子筛经水热处理和酸处理 ,调变了孔结构和酸性 ,进而提高其催化活性     

Hydrotreating catalysts containing zeolites and related materials—mechanistic aspects related to deep desulfurization

The deep hydrodesulfurization (HDS) of diesel fuels requires the decomposition of refractory compounds such as 4,6-dimethyldibenzothiophene (46DMDBT). There is a general agreement on the fact that the low reactivity of these compounds is due to steric hindrance of the transition state leading to C–S bond cleavage, which annihilates the effect of the promoter to a large extent. The consequence is that their so-called “direct desulfurization pathway” is particularly inhibited.

Various issues were considered to circumvent the difficulty to eliminate the HDS-resistant molecules and therefore to reach deep desulfurization. Two of them at least consist in designing new hydrotreating catalysts (in addition to the improvement of the alumina-supported conventional catalysts): (i) catalysts with improved hydrogenation properties; (ii) bifunctional catalysts containing an acid component. The main findings obtained with the first class of catalysts are summarized. On these catalysts HDS was found very sensitive to the inhibition by aromatics. The studies regarding the second category of catalysts are analyzed in more detail. Several techniques were used to introduce acid components, including mesoporous materials, in hydrotreating catalysts: physical mixing, binding, deposition of sulfide precursors on an acid–alumina support, deposition of sulfide precursors on an acidic support. Most of these catalysts were found more active than conventional catalysts in the HDS of compounds such as 46DMDBT. The various interpretations of the effect of the acid component are reported and discussed. It is however generally accepted that the improvement of the reactivity, on this category of catalysts, of the HDS-resistant compounds is due to their acid-catalyzed isomerization and disproportionation into more reactive derivatives. When acidic materials were used directly as supports it was difficult to obtain a good association of, for instance, molybdenum, with promoters. Nevertheless, in certain cases catalysts were obtained which were more active than conventional catalysts in the HDS of compounds such as 46DMDBT or of gas oils containing such impurities. However although the catalysts containing acid components proved efficient in hydrotreating various kinds of oils, they suffer several drawbacks such as deactivation by coke deposition and inhibition of HDS by aromatics. Moreover nitrogen impurities which inhibit HDS even with conventional catalysts may also impede seriously their use in practice.     

羧酸酯合成新型催化剂的研究

研究了对甲苯磺酸、硫酸铁、硫酸铈作为催化剂在羧酸酯（丁酸乙酯）合成中的应用。实验表明，这些催化剂具有较好的催化活性，可使酯化反应大大缩短，收率明显提高。     

The study of methanol aromatization on transition metal modified ZSM-5 catalyst

In this article, transition metals of Cu, La and Zn were used as adjuvant to prepare modified HZSM-5 by impregnation method. The catalysts were characterized by XRD, BET, NH₃-TPD and Py-IR to reveal the microstructure and acid property. The catalysis performances of methanol aromatization of catalysts were investigated in a fixed-bed reactor. The results show that the strength and distribution of acid center of these catalysts are significantly influenced by the species of transition metal. There are more mediate strong Lewis acid center in Zn modified HZSM-5 catalyst and therefore exhibits higher selectivity to aromatic, benzene, toluene and xylenes in the MTA reaction..     

乙烯路线制备甲基丙烯酸甲酯研究进展

甲基丙烯酸甲酯（MMA）是一种重要的基础有机化工原料，主要用于生产有机玻璃、塑料改性剂及表面涂料等诸多行业，具有非常广阔的发展前景，MMA 合成路线众多。本文综述了以乙烯为起始原料，经过羰基化反应制备丙醛、丙酸和丙酸甲酯等中间产物，然后经羟醛缩合反应制备MMA的研究进展。概述了乙烯制备MMA的3条工艺路线及其发展趋势，指出中间产物与甲醛的缩合反应是乙烯路线的关键步骤，重点介绍了羟醛缩合反应及其催化剂的研究现状。目前用于气相催化羟醛缩合反应的催化剂主要有V、Si、P酸性催化剂和K、Cs碱性催化剂，其中以Cs为主活性组分的碱性催化剂研究最为广泛，载体种类、助剂、制备方法、反应条件等对催化剂的活性、选择性和寿命等具有较大影响。为进一步改善催化剂的性能，需加强对羟醛缩合反应催化机理的研究，具有酸碱两性的复合催化剂是今后重点研究方向。     

Synthesis and Characterization of Lewis Acid Doped Polyaniline and Its Application as Catalysts for Acetalization of Carbonyl Compounds

Lewis acid doped polyanilines are prepared by doping of polyaniline base with Lewis acids. Polyaniline base and Lewis acid doped polyanilines are characterized by physical and spectral methods. They are used as catalysts for the first time for acetalization of carbonyl compounds. The catalyzed acetalization of benzaldehyde with propane-1,2-diol is conducted in excellent yields with simple and more environmentally benign procedure. The use of these doped lewis acid catalysts is feasible because of being ecofriendly, their easy preparation, easy recovery, reusability, and good activity.     

Efficient hydroalkoxylation of alkenes to generate octane-boosting ethers using recyclable metal triflates and highly active metal triflate/Brønsted acid-assisted catalysts

gem-Disubstituted alkenes are directly and readily etherified with alcohols using Al(OTf)₃ and Zr(OTf)₄ as recyclable Lewis acid catalysts. In contrast, primary or secondary alkene analogues were inert under these conditions, enabling excellent chemoselectivity. Lanthanide triflates are inactive as catalysts for such reactions, as is phosphoric acid. But a combination of these two otherwise inactive entities led to an ‘assisted acidity’ scenario that saw significant unmatched catalyst activity. All catalysts of this study are recyclable a number of times without loss of activity.