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查尔酮合成方法的研究进展 总被引:4,自引:0,他引:4
查尔酮是一种黄酮类化合物,其常见合成方法是以苯甲醛和苯乙酮为原料,加入碱、酸或金属等物质作为催化剂进行醛酮缩合反应,但产率较低,副产物多。近年来查尔酮化合物的合成采用了新技术,是以苯甲醛和苯乙酮为原料,BF4作为反应溶剂,水滑石为催化剂,在温度为343 K的条件下进行反应,查尔酮产率可以达到98.5%,该法具有反应时间短、操作简便、收率高等优点。分析了近年来查尔酮几种合成方法的优缺点,催化剂的选择及其适用的条件。 相似文献
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查尔酮及其衍生物是芳香醛酮发生交叉羟醛缩合的产物,是合成多种天然化合物重要的有机合成中间体。据报道查尔酮类化合物是一类存在于甘草、红花等药用植物中的天然有机化合物,由于其分子结构具有较大的柔性,能与不同的受体结合,得到的化合物具有广泛的生物活性,如抗肿瘤、抑制和清除氧自由基、抗菌、抗过敏、抗病毒、抗溃疡和解痉等生物活性。 相似文献
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This paper describes experimental work done towards the search for more profitable and sustainable alternatives regarding biodiesel production, using heterogeneous catalysts instead of the conventional homogenous alkaline catalysts, such as NaOH, KOH or sodium methoxide, for the methanolysis reaction. This experimental work is a first stage on the development and optimization of new solid catalysts, able to produce biodiesel from vegetable oils. The heterogeneous catalytic process has many differences from the currently used in industry homogeneous process. The main advantage is that, it requires lower investment costs, since no need for separation steps of methanol/catalyst, biodiesel/catalyst and glycerine/catalyst. This work resulted in the selection of CaO and CaO modified with Li catalysts, which showed very good catalytic performances with high activity and stability. In fact FAME yields higher than 92% were observed in two consecutive reaction batches without expensive intermediate reactivation procedures. Therefore, those catalysts appear to be suitable for biodiesel production. 相似文献
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偶联反应一般是指C-C偶联或C-N等的偶联,像Still反应、Suzuki反应和Buchwald反应等,它们中的反应催化剂一直以来是使用均相钯配体催化剂,对于负载型钯催化剂的使用较少。将载钯催化剂用于偶联反应是有机合成反应中均相反应多相化的典型例子,且在工业化生产中较均相催化剂更具有优势。从负载钯催化剂的制备、介孔碳的制备及反应驱动力三个方面介绍了偶联反应的近期进展,并对未来发展进行了展望。 相似文献
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The Heck reaction finds several applications in industry because it is one of the effective tools for the formation of a new C─C bond. In addition to the catalytic activity and selectivity, catalyst-product separation strategies are very important for the industrial application. There are various methods of interest ranging from conventional heterogeneous catalysts to heterogenization of homogeneous catalysts. The heterogeneous catalysts are classified into supported metal catalysts, zeolite-encapsulated catalysts, colloids-nanoparticles, and intercalated metal compounds. The homogeneous metal complexes catalysts are heterogenized using modified silica catalysts, polymer-supported catalysts, biphasic catalysts, supported liquid-phase catalysts, nonionic liquids solvents, perfluorinated solvents, and reusable homogeneous complexes. In general, heterogeneous catalysts are effective and stable at higher temperatures, which may be important for the activation of less reactive but less expensive chloroaryls substrates. However, the heterogeneous catalysts have a major drawback of poor selectivity toward Heck coupling products. The heterogenized metal complexes catalysts operate under relatively mild conditions as compared with heterogeneous catalysts, and so they can be applied to the production of pharmaceuticals and fine chemicals. Catalysis using supercritical solvents with catalyst separation techniques is promising for the development of green chemistry processes. Although the concepts described in this article have been reviewed mainly for Heck reactions, they should be applicable to a wide range of other chemical transformations (hydrogenation, carbonylation, hydroformylation, and so on) that, currently, are homogeneously catalyzed reactions. 相似文献
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二氧化碳和甲醇直接合成碳酸二甲酯研究进展 总被引:2,自引:1,他引:1
从均相及多相催化剂体系和反应条件等方面,综述了近年来二氧化碳和甲醇直接合成碳酸二甲酯的研究开发最新进展。介绍了均相催化剂体系包括有机金属烷氧基化合物、碱土金属烷氧基化合物、碱性催化剂和乙酸盐催化剂;多相催化剂体系包括负载型金属催化剂、负载型固体碱催化剂和氧化物催化剂。对催化剂及反应体系的设计、光催化剂、杂多酸催化剂、离子液体体系、助催化剂及吸水剂的使用、微波加热、膜反应器以及超临界二氧化碳溶剂体系进行了评述。 相似文献
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非均相催化法生产生物柴油的研究进展 总被引:1,自引:0,他引:1
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。 相似文献
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