烯烃水合反应工艺与催化剂研究进展

综合介绍了多种烯烃水合反应的机理、生产工艺及催化剂的研究成果。分类详细归纳了环己烯、丙烯、高碳烯烃等通过水合反应生产相应产物醇的生产工艺和催化剂的最新研究进展，并分析了烯烃水合技术的未来发展趋势。分析发现：烯烃水合反应的路径主要分为直接路径和间接路径；其反应机理主要有马氏规则的亲电加成机理、反马氏规则的亲电加成机理、自由基反应机理等；烯烃水合反应用催化剂从液体酸、碱，过渡金属盐或氧盐，不断向分子筛、固体酸、合成树脂、光催化剂、酶催化剂方向发展。未来，光催化和生物酶催化是烯烃水合科技研究的重点方向；而反应设备参数优化、提升催化剂性能、强化物料混合效果、改善传质过程等，则是烯烃水合生产工艺优化的发展趋势。     

非均相催化法生产生物柴油的研究进展

综述了国内外非均相催化法生产生物柴油的现状,介绍了非均相固体酸催化剂、固体碱催化剂和固定化生物酶的最新研究进展,展望了未来生物柴油生产技术的发展趋势。     

酮与伯醇的α-烷基化反应研究进展

以伯醇为烷基化试剂对酮的α-烷基化反应是有机合成中的基本反应,是构建C—C键的重要方法。廉价易得的环境友好型原料醇类化合物作为亲电试剂,通过氢转移对酮进行α-烷基化反应,副产物只有水。综述了该反应的过渡金属催化剂、双金属催化剂和固体酸催化剂,其中,过渡金属催化剂尤其受重视。     

三种反应条件下合成C22-三酸三酯 的结构分析(论文集论文)

以生物柴油中的亚油酸甲酯与马来酸二丁酯(DBM)为原料,分别以碘、固体碱为催化剂或在仅加热的条件下合成了C22-三酸三酯。采用傅里叶变换红外光谱(FTIR)、核磁共振(NMR)和质谱(MS)对产物结构进行表征。结果表明,以碘作为催化剂时,生成具有环己烯结构的C22-三酸三酯,反应为Diels-Alder环加成反应;以固体碱KOH/活性白土作催化剂时,生成主链具有共轭结构的悬挂型C22-三酸三酯,反应可能按照碳负离子历程进行;在不用催化剂、仅加热的条件下,也生成主链具有共轭结构的悬挂型C22-三酸三酯,反应可能按照自由基反应机理进行。     

Ca-Al-LDHs固体碱催化羟甲基化反应制备2-硝基-2-甲基-1-丙醇的研究

采用共沉淀法制备了一系列Ca-Al-LDHs固体碱催化剂用于非均相催化合成2-硝基-2-甲基-1-丙醇。利用XRD、SEM、XPS、CO₂-TPD、FT-IR、BET等分析手段对Ca-Al-LDHs的结构特性、金属价态、碱性强度与催化性能构效关系进行表征,通过2-硝基丙烷与甲醛羟甲基化反应评价了Ca-Al-LDHs固体碱催化剂的催化性能,并对2-硝基-2-甲基-1-丙醇的制备工艺进行了优化。结果表明,所制备的固体碱催化剂表面存在大量强碱性活性位点,并且存在一种新的晶格结构(Ca₁₂Al₁₄O₃₃),该结构的存在提高了该催化剂对羟甲基化反应的催化性能;在温度为70℃、反应时间为2 h、n(甲醛)∶n(2-硝基丙烷)=2∶1、m(催化剂)∶m(甲醛)=3∶10的反应条件下,2-硝基丙烷的转化率为96.2%,2-硝基-2-甲基-1-丙醇选择性为99%。催化剂重复使用20次后,产品收率仍能达到60%以上。     

催化酯交换制备生物柴油的研究进展

催化酯交换是制备生物柴油的一个重要方法。本文综述了均相催化和非均相催化、酸性催化和碱性催化、固体酸和固体碱催化的研究进展,并针对每类催化剂的特性和应用范围进行比较,得出固体酸和固体碱催化符合绿色生产生物柴油的要求,是未来发展的方向。特别是固体酸在催化含有水分和游离酸的油脂酯交换方面具有独特的优势,需要进一步研究和开发。     

微波促进生物柴油制备的研究进展

以微波为促进手段进行生物柴油制备近几年受到广泛关注,本文从均相和非均相催化转酯化反应的角度,综述了微波促进生物柴油制备的国内外研究进展。与非均相催化过程相比,均相催化过程的研究更加广泛。均相催化剂的研究多以碱性催化剂为主,其反应速率快,但是副反应多。非均相催化剂的研究中,均有采用固体酸或者固体碱催化剂的报道,其中以活性炭为载体的固体催化剂具有廉价、高效的特点,但是其催化剂寿命需要进一步提高。     

固体酸催化剂上酯化反应研究进展

评述了国内外对沸石催化剂、固体超强酸、固体杂多酸和强酸性阳离子交换树脂等固体酸催化剂催化酯化反应的研究成果和动态，包括所涉及的反应物系、反应机理、催化性能与催化剂酸性质的关系等。认为用固体酸取代传统催化剂硫酸进行催化酯化的新型工艺开发是大有前途的。     

磁性固体超强酸催化酯化反应的研究进展

磁性固体超强酸是一类具备选择性高、催化活性高、在外磁场存在下易于产物分离,方便回收.可逐渐替代了液体酸的酯化反应,在非均相反应中具有广泛的应用前景的催化剂综述了此类催化剂改性的制备方法和失活再生.县体介绍了金属或金属氧化物、分子筛与载体相结合.将明显提高催化效率和催化剂的重复使用性能。磁性固体超强酸是一类新型环保的绿色催化剂。     

动态动力学拆分制备手性化合物的研究进展

综述了固体酸、固体碱和金属配合物在动态动力学拆分制备光学纯手性化合物进行外消旋化的催化机理,讨论了均相外消旋催化剂和多相外消旋催化剂在动态动力学拆分工艺中的应用,重点介绍了过渡金属配合物催化剂和生物酶配伍进行动态动力学拆分制备手性化合物的研究进展和发展趋势。     

固体强碱绿色催化环氧丙烷水解合成1,2-丙二醇

该文制备了不同碱强度的固体碱催化剂,并应用于环氧丙烷(PO)水解合成1,2-丙二醇的反应。结果表明:随着催化剂碱强度的增加,环氧丙烷的转化率不断升高;说明强碱催化剂有利于环氧丙烷水解反应。在此基础上,作者系统考察了催化剂用量、反应温度、原料摩尔比和反应时间对催化性能的影响。结果表明:当催化剂CaO-ZrO2质量为反应原料质量的1.0%,反应温度为120℃,反应原料配比为:n(H2O)∶n(PO)=5∶1,反应时间2h时,其催化效果较优,环氧丙烷转化率最高为92.3%,1,2-丙二醇选择性可达89.4%。     

绿色化学研究进展

对绿色化学在新型催化剂和反应介质方面的研究进展进行了综述。新型催化剂主要包括固体酸催化剂、固体碱催化剂、金属催化剂等。这些催化剂不仅具有较高的活性和选择性,而且催化剂和反应体系易于分离。新型反应介质主要包括超临界流体和离子液体,它不仅可以替代传统的有毒有害的挥发性有机溶剂,同时可以提高反应的活性和选择性,并且易于回收利用。高效催化剂和绿色反应介质的研究开发是未来绿色化学的重要研究内容。     

Rational approach to polymer-supported catalysts: synergy between catalytic reaction mechanism and polymer design

Supported catalysis is emerging as a cornerstone of transition metal catalysis, as environmental awareness necessitates "green" methodologies and transition metal resources become scarcer and more expensive. Although these supported systems are quite useful, especially in their capacity for transition metal catalyst recycling and recovery, higher activity and selectivity have been elusive compared with nonsupported catalysts. This Account describes recent developments in polymer-supported metal-salen complexes, which often surpass nonsupported analogues in catalytic activity and selectivity, demonstrating the effectiveness of a systematic, logical approach to designing supported catalysts from a detailed understanding of the catalytic reaction mechanism. Over the past few decades, a large number of transition metal complex catalysts have been supported on a variety of materials ranging from polymers to mesoporous silica. In particular, soluble polymer supports are advantageous because of the development of controlled and living polymerization methods that are tolerant to a wide variety of functional groups, including controlled radical polymerizations and ring-opening metathesis polymerization. These methods allow for tuning the density and structure of the catalyst sites along the polymer chain, thereby enabling the development of structure-property relationships between a catalyst and its polymer support. The fine-tuning of the catalyst-support interface, in combination with a detailed understanding of catalytic reaction mechanisms, not only permits the generation of reusable and recyclable polymer-supported catalysts but also facilitates the design and realization of supported catalysts that are significantly more active and selective than their nonsupported counterparts. These superior supported catalysts are accessible through the optimization of four basic variables in their design: (i) polymer backbone rigidity, (ii) the nature of the linker, (iii) catalyst site density, and (iv) the nature of the catalyst attachment. Herein, we describe the design of polymer supports tuned to enhance the catalytic activity or decrease, or even eliminate, decomposition pathways of salen-based transition metal catalysts that follow either a monometallic or a bimetallic reaction mechanism. These findings result in the creation of some of the most active and selective salen catalysts in the literature.     

三齿配体过渡金属烯烃聚合催化剂研究新进展

介绍了三齿配体结构、中心金属原子、助催化剂、负载化等对催化剂性能的影响;综述了三齿配体过渡金属烯烃聚合催化剂在乙烯齐聚、乙烯聚合、丙烯聚合以及极性单体聚合方面的应用以及三齿配体过渡金属烯烃聚合催化剂的催化机理方面的研究进展。     

窄分布醇醚合成用催化剂的筛选与催化作用分析

讨论了酸、碱催化剂对窄分布醇醚合成反应的催化性能。从反应物转化率、醇醚产物选择性和醇醚分子量分布窄度几个方面综合考察了酸、碱类催化剂的优缺点,发现酸性催化剂的催化活性普遍较高,均在９５％以上,产物分子量分布较窄,ｎ＜５的产物占醇醚产物总质量的８５％左右,但生成的非醇醚类产物杂质较多,占反应产物质量的１４％以上;碱性催化剂的催化活性不一,其中活性较高的固体碱类镁铝复合金属氧化物（ＬＤＯ）与酸性催化剂活性相当,达９９．９％,且其产物纯净,非醇醚类产物仅占反应产物质量的１．２％,其醇醚产物分子量分布虽然宽于酸性催化剂,ｎ＜５的醇醚占醇醚产物质量的７７．２％,但明显窄于工业上普遍应用的均相催化剂ＫＯＨ（６６．８％）,是较有发展前景的催化剂。     

Catalytic Dimerization of Alkyl Acrylates

The review deals with the chemistry of dimerization of acrylic esters in the presence of various catalysts. The article covers literature from 1963 through early 1995. The dimerization reactions are divided into three categories depending on the type of catalyst used, namely, phosphine-catalyzed, metal-catalyzed, and miscellaneous catalysts. Phosphine catalyzed dimerization leads to branched or head—tail dimers. Metal catalyzed dimerization deals with the reactions that take place in the coordination sphere of the transition metals (Ni, Pd, Ru, and Rh) complexes and are aimed at linear or tail—tail dimers. The tail—tail dimers, dialkyl hexenedioates, have a commercial potential as precursors of adipic acid, which is a raw material in the manufacture of nylon-6,6. Various strategies involved in designing the transition metal catalysts for tail—tail dimerization are highlighted. A miscellaneous catalyst section deals with systems that are not covered under the above two categories. It describes catalyst systems comprised of organic and/or inorganic compounds leading to head—tail or tail—tail dimers. The hydrodimerization reactions, which directly give dialkyl adipate from acrylic ester, are discussed separately. The mechanisms of the important dimerization reactions are outlined at appropriate places.     

Catalytic Dimerization of Alkyl Acrylates∗

The review deals with the chemistry of dimerization of acrylic esters in the presence of various catalysts. The article covers literature from 1963 through early 1995. The dimerization reactions are divided into three categories depending on the type of catalyst used, namely, phosphine-catalyzed, metal-catalyzed, and miscellaneous catalysts. Phosphine catalyzed dimerization leads to branched or head—tail dimers. Metal catalyzed dimerization deals with the reactions that take place in the coordination sphere of the transition metals (Ni, Pd, Ru, and Rh) complexes and are aimed at linear or tail—tail dimers. The tail—tail dimers, dialkyl hexenedioates, have a commercial potential as precursors of adipic acid, which is a raw material in the manufacture of nylon-6,6. Various strategies involved in designing the transition metal catalysts for tail—tail dimerization are highlighted. A miscellaneous catalyst section deals with systems that are not covered under the above two categories. It describes catalyst systems comprised of organic and/or inorganic compounds leading to head—tail or tail—tail dimers. The hydrodimerization reactions, which directly give dialkyl adipate from acrylic ester, are discussed separately. The mechanisms of the important dimerization reactions are outlined at appropriate places.

     

FI Catalysts: A Molecular Zeolite for Olefin Polymerization

A bis(phenoxyimine) group 4 transition metal catalyst (now known as FI catalysts) can discern ethylene from a mixture of ethylene and propylene at more than 99% selectivity. Denisty function theory (DFT) calculations revealed a spatially confined reaction site in the transition states of the migratory insertion which is just the right size for an ethylene molecule but too small for a propylene one. The substituents adjacent to the phenoxy‐oxygens are of crucial importance in developing the size/shape‐selectivity.     

丙烯环氧化合成环氧丙烷新技术的研究进展

评述了以分子氧和双氧水为氧源的丙烯环氧化催化剂体系的最新研究进展。其中包括金属Ag催化剂。金属熔盐混合物，钛硅沸石TS-1和过渡金属络合物催化剂体系，根据氧转移机理。金属Ag催化剂和熔盐体系是以分子氧为直接氧源，而TS-1和最近报道的反应相转移含钨催化剂本质上是以过氧化氢为直接氧源。TS-1和反应相转移含钨催化剂和优点是反应条件较温和，生成环氧丙烷的选择性和产率较高。如一种负载成“蛋壳醇作为溶剂），环氧丙烷选择性和产率（以双氧水计）分别可达92%和90%以上。催化剂运转1000h以上性能稳定，今后的一个重要发展方向是开发以分子氧为起始氧源，简单高效的原位双氧水工艺。     

乙基叔丁基醚合成催化剂的研究进展

综述了国内外合成乙基叔丁基醚(ETBE)的催化剂研究现状,介绍了ETBE在不同催化剂上合成的反应机理。比较了阳离子交换树脂、分子筛、固体超强酸和杂多酸等不同催化剂的催化活性、选择性、稳定性等特点;讨论了采用催化精馏法合成ETBE时催化剂的各种装填技术。指出今后的研究方向是采用引入拉电子基团的方法改善树脂催化剂的热稳定性和选择性,通过离子交换等调节酸性的方法进一步提高分子筛催化剂的催化活性;同时应加强对固体超强酸和杂多酸催化剂的基础研究。