糠醛液相催化加氢制糠醇金属催化剂的研究进展

糠醛催化加氢是将糠醛转化为生物燃料、医药农药中间体等精细化学品的最常用的反应之一,如糠醇、2-甲基四氢呋喃、内酯、乙酰丙酸盐、环戊酮等皆由糠醛催化加氢制取.当前糠醛催化加氢的过程主要有液相、气相以及催化转移加氢等.综述了近年来糠醛液相催化加氢制备糠醇的不同金属基催化剂的研究进展.从不同过渡金属和贵金属作为催化活性中心制...     

羧酸／烯烃酯化合成羧酸酯工艺及催化剂研究进展

从工艺及催化剂的开发两个方面介绍了由羧酸与烯烃酯化合成羧酸酯工艺的研究进展。所涉及的催化剂包括矿物酸及磺酸、金属硫酸盐、粘土矿物、氧化物、沸石分子筛、杂多化合物及离子交换树脂。离子交换树脂对于乙酸／丙烯和乙酸／１丁烯的酯化反应具有良好的催化活性及稳定性,杂多化合物则是目前最好的乙酸／乙烯酯化反应的催化剂。     

用路易斯酸作催化剂制取羧酸酯

1 前言羧酸与醇直接酯化时,一般使用浓硫酸作催化剂。浓硫酸具有酸性强、催化效果好、性质稳定等优点;但其具有氧化性,并可导致磺化、碳化及聚合等副反应,且其腐蚀性强,对工艺设备条件要求较高,尤其对碳链较长、分     

草酸酯催化加氢制备乙二醇研究进展

综述了近年来碳一合成路线中草酸酯催化加氢制备乙二醇的研究进展。分别介绍了以Ru等贵金属催化剂为主的液相均相加氢法和以铜基催化剂为主的非均相气相或液相加氢法,详细介绍了各类催化剂在草酸酯催化加氢方面的特点。并且就目前国内外对草酸酯氢化动力学方面的研究予以总结,给出了草酸酯加氢过程典型的动力学过程。最后比较了分别以草酸二甲酯和草酸二乙酯为原料路线的优缺点。     

石油树脂加氢催化剂研究进展

高端氢化石油树脂应用广泛,市场需求逐年增加,如何实现高效生产高品质氢化石油树脂是该领域研究的重点。高品质氢化石油树脂的生产主要是采用催化加氢技术,开发高效稳定的加氢催化剂是关键的技术环节。本文针对催化剂加氢效率低、树脂分子扩散与吸附困难、加氢反应条件苛刻等问题,重点综述了近年来研究者为解决上述难点在催化剂金属活性组分组成、几何与电子结构、载体形貌与孔结构设计等方面的研究成果。提出催化剂中金属活性位点的分散度、位点分布情况、价态调控及复合金属间的协同作用是调控催化剂性能的关键。同时,对目前石油树脂加氢催化剂活性位点设计、反应机理、催化剂失活再生机制等方面进行总结并展望催化剂的未来发展方向。     

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。     

植物油加氢催化剂的研究进展

综述了植物油加氢催化剂的研究现状,介绍了植物油的基本特点以及影响其加氢的因素,表明催化剂是植物油加氢的关键,介绍了不同体系催化剂在植物油加氢中的研究现状,其中重点介绍了Ni基催化剂、Cu基催化剂、Pd基催化剂和Pt基催化剂在植物油加氢行业的研究状况及发展,以及影响催化剂催化活性的因素,催化剂的材料、催化剂载体等。指出植物油加氢催化剂是由贱金属向贵金属、单元体金属向多元体金属以及加强对载体和活性组分负载技术研究的发展趋势。     

SBS新型加氢催化剂

以ＲｖＣｌ２（ＰＰｈ３）３为催化剂,ＰＰｈ３为配体对ＳＢＳ加氢,产物加氢度为９８％,该催化剂既有高活性又有高选择性（苯环未加氢）,产物无凝胶。通过初始分解温度测试表明,加氢产物的耐热性有很大提高。此外Ｒｈ－Ｒｕ双金属催化剂在ＳＢＳ加氢中比Ｒｕ音金属催化剂具有更高的催化活性。     

羧酸酯催化合成的新方法

选用超强酸树脂ＤＯＯ１－ＡｌＣＩ＿３代替强酸性阳离子交换树脂及浓硫酸作催化剂，对乳酸正了酯合成反应进行了探索性研究，讨论了影响产率的多种因素，最佳条件下酯化反应时间缩短，乳酸正丁酯产率可达到９９．５％。对其他酯类物质也进行了合成试验，获得了满意的结果。     

多不饱和脂肪酸及其酯的选择性加氢研究进展

尽管部分加氢是提高多不饱和脂肪酸及其酯性能的一种有效方式,但加氢过程中反式异构体的生成会影响油脂的品质,因此,对油脂加氢反应中如何减少反式异构体生成的研究具有一定的意义。首先,介绍了多不饱和脂肪酸及其酯加氢机理及反式异构体生成的原理。然后,综述了加氢方式、加氢催化剂(包括活性组分、助剂、载体及催化剂制备方法)对反式异构体生成影响的研究新进展。最后,对影响反式异构体生成的规律进行总结,进而提出了多不饱和脂肪酸及其酯加氢过程中以减少反式异构体生成为目的的措施。     

羧酸酯还原制备醇的方法研究进展

羧酸酯还原成醇是有机化学中的一类重要反应,有着广泛的用途。在涉及此类还原反应的已有文献资料中,所使用的还原体系包括硼烷、氢化铝锂、二异丁基氢化铝、红铝、金属硼氢化物等,其中,这些体系的还原能力各不相同。本文简要介绍了以上不同还原体系的研究新进展,综述了不同还原体系用于酯还原反应的反应机理,并通过不同还原体系间的比较与实例列举,为酯的还原研究提供了一些新的思路和方法,如还原体系的投料配比、投料顺序及与不同添加剂的配伍均可影响反应结果,使部分反应的收率高达90%以上,并使酯还原成醇的反应以更温和的方式进行。指出反应选择性更好,适用范围更广,反应条件更温和的新试剂、新方法将不断涌现,这将会给羧酸酯还原的领域带来更新的发展。     

共反应剂法合成金刚烷甲酸纤维素酯

In order to develop a novel bioactive material utilizing cellulose resource, adamantane carboxylic acid esters of cellulose were synthesized through in-situ activation of the adamantane carboxylic acid using N,N-dimethylacetamide/LiCl as solvent, p-toluenesulfonyl chloride as co-reagent.The structure and properties of adamantane carboxylic acid esters of cellulose were characterized by means of IR, ¹H NMR, TG,etc.The esterification conditions were investigated in detail.The results showed that the degree of substitution was influenced by reaction temperature, reaction time and mole ratios of repeat units of cellulose/adamantane carboxylic acid/p-toluenesulfonyl chloride.Under the optimized reaction conditions, the highest degree of substitution (DS) was 1.9.TG analysis revealed that the thermal stability of cellulose esters was improved with the increase of DS due to the incorporation of adamantane carboxylic acid into chains of cellulose.The products are soluble in various organic solvents, depending on the DS.     

芳基撑双吡唑酮羧酸酯的合成及表征

以芳香族二元酸为原料通过3步反应合成了两个芳基撑双吡唑酮羧酸酯,用红外、核磁及质谱对其结构进行了表征。     

Hydrogenation of fatty acid methyl esters to fatty alcohols at supercritical conditions

Extremely rapid hydrogenation of fatty acid methyl esters (FAME) to fatty alcohols (FOH) occurs when the reaction is conducted in a substantially homogeneous supercritical phase, using propane as a solvent, over a solid catalyst. At these conditions, the limitations of hydrogen transport are eliminated. At temperatures above 240°C, complete conversion of the starting material was reached at residence times of 2 to 3 s, which is several orders of magnitude shorter than reported in the literature. Furthermore, formation of by-products, i.e., hydrocarbons, could be prevented by choosing the right process settings. Hydrogen concentration turned out to be the key parameter for achieving the above two goals. As a result of the supercritical conditions, we could control the hydrogen concentration at the catalyst surface independently of the other process parameters. When methylated rapeseed oil was used as a substrate, the hydrogenation catalyst was deactivated rapidly. However, by using methylated sunflower oil, a catalyst life similar to that obtained in industrial processes was achieved. Our results showed that the hydrogenation of FAME to FOH at supercritical conditions is a much more efficient method than any other published process.     

手性修饰催化剂在多相不对称氢化中的研究进展

手性修饰金属催化剂是最具发展潜力的多相不对称催化剂之一。本文综述了近年来三个具有代表性的多相不对称氢化反应体系的研究进展,即酒石酸修饰镍催化剂催化β-酮酯不对称加氢体系、金鸡纳生物碱修饰铂催化剂催化α-酮酯不对称加氢体系以及金鸡纳生物碱修饰钯催化剂催化C=C和C=N双键不对称加氢体系。概述了催化体系的影响因素,探讨了酒石酸及金鸡纳生物碱修饰型催化剂的手性识别机理模型。指出开发高效催化剂,修正或提出手性识别机理模型仍是今后多相不对称催化氢化反应研究的方向。     

Enhanced synergy between Cu0 and Cu+ on nickel doped copper catalyst for gaseous acetic acid hydrogenation

As the substitution of common noble catalysts in the hydrogenation of carboxylic acid, a highly effective Cu-Ni/SiO₂ catalyst was prepared by a novel stepwise ammonia evaporation method. Its performance in the gas-phase hydrogenation of acetic acid was further examined. With the introduction of Ni dopant, more stable Cu^δ+ sites, which can adsorb more acetic acid, were formed due to the electron transfer from Cu to Ni. This makes more Cu⁰ sites available for hydrogen adsorption, which was suggested as the rate-determining step in acetic acid hydrogenation. A conversion of 99.6% was successfully achieved on this new Cu/SiO₂-0.5Ni catalyst, accompanied by the ethanol selectivity of 90%. The incorporation of nickel between copper nanoparticles enhances the synergistic effect between Cu⁰ and Cu⁺. It also helps mitigate the aggregation of copper nanoparticles due to the Ostwald ripening effect induced by acetic acid and enhance the stability of copper catalyst in the conversion of carboxylic acid.     

Synthesis of glycidyl esters

A novel method of synthesis of glycidyl carboxylates (2,3‐epoxypropyl carboxylates, RCOOCH₂CH‐CH₂O) has been developed by carrying out the reaction of epichlorhydrin with a carboxylic acid in the presence of chromium acetate catalyst and subsequent dehydrochlorination of the resulting mixture of chlorohydrin esters followed by their separation. © 1999 Society of Chemical Industry     

催化加氢法合成芳磺酸氨基化合物

阐述了W-2型兰尼镍催化剂在芳磺酸硝基化合物催化加氢还原制备芳磺酸氨基化合物中的应用。以间硝基苯磺酸的催化加氢反应为例进行试验,结果表明,在反应温度80～100℃、反应压力1MPa、反应时间3h的条件下,间氨基苯磺酸产品的含量为99%,收率可达99%以上,催化剂可以连续循环使用20次。     

Unprecedented Reductive Esterification of Carboxylic Acids under Hydrogen by Reusable Heterogeneous Platinum Catalysts

Supported metal catalysts have been tested for an unprecedented reductive dimerization of carboxylic acids to esters under 8 bar hydrogen in solvent‐free conditions. Among various metal‐loaded tin oxide catalysts, platinum‐loaded tin dioxide (Pt/SnO₂) shows the highest ester yield for the reaction of dodecanoic acid. Among Pt catalysts on various supports, Lewis acidic oxides, especially SnO₂, show high activity. The most active catalyst, 5 wt% Pt/SnO₂ reduced at 100 °C, is effective for the reductive esterification of various carboxylic acids, and the catalyst is reusable for nine cycles, demonstrating the first successful example for the title reaction. Infrared (IR) studies of a model compound (formic acid) on some metal oxides indicate a strong Lewis acid‐base interaction between SnO₂ and the carbonyl oxygen. For Pt/SnO₂ catalysts with different Pt particle sizes, the activity increases with decreasing size of Pt metal. A cooperative catalysis of the Pt metal nanoparticles and the Sn⁴⁺ Lewis acid sites is proposed.