共查询到18条相似文献,搜索用时 109 毫秒
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《制药原料及中间体信息》2007,(4):26-28
合成VD的方法有热化学和光化学方法。热化学反应合成维生素D要经过20余步,光化学方法合成VD则简单得多。20世纪30年代初,科学家们就已经提出了从麦角固醇出发,利用光化学方法合成VD2的路线,麦角固醇光照得到VD2的过程相对简单,但产生多个复杂的副产物,给VD2的分离提纯造成极大困难。另外,VD2以及中间体对光、热、空气都很敏感,因此在合成过程中对控制反应与后处理的条件要求极为苛刻。 相似文献
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维生素A合成工艺评述 总被引:1,自引:0,他引:1
本文首先介绍了维生素A的Roche和BASF两条合成工艺路线,指出了两条工艺路线的不同技术特征和关键技术难点。阐述了BASF技术路线关键合成步骤的技术开发动态。对国内外工业合成维生素A主要采用的Roche合成工艺的关键中间体的合成进行重点阐述,总结了值得深入研究的合成新工艺、新方法和技术研究开发方向。 相似文献
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简介维生素D2的调节钙磷代谢、抑制癌细胞增殖、调节血压和免疫系统等功能,广泛应用于医药、食品、饲料等领域。重点论述国内维生素D2研究与产业化开发现状,详细介绍了维生素D2的光化学法生产工艺,展望了维生素D2广阔的市场前景。 相似文献
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通过对呋喃酚几条合成路线的比较,对目前国内外呋喃酚合成技术及邻苯二酚生产情况进行了分析,并提出呋喃酚合成改进的方向。作者认为我国已具备开发呋喃酚工业化路线的能力。 相似文献
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通过对呋喃酚几条合成路线的比较,对目前国内外呋喃酚合成技术及邻苯二酚生产情况进行了分析,并提出呋喃酚合成改进的方向。作者认为我国已具备开发呋喃酚工业化路线的能力。 相似文献
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光化学转化是有效利用光能实现化学反应的重要途径,微反应技术为提高其过程效率提供了一个强有力的平台。本文首先指出微反应器相比于传统釜式光反应器,在光强分布、过程放大、光能利用效率等诸多方面存在明显的优势,能够实现光化学反应过程的高效强化。简要地介绍了光化学转化及光化学微反应技术的基本特征,然后系统地综述了光化学微反应器的设计构建及其在有机合成、聚合等方面的应用,并详细介绍了自动化控制的光化学微反应系统及应用。重点介绍了微反应技术在紫外光、可见光辐照下的光化学合成进展及其过程放大。最后,对光化学微反应技术的研究进展进行总结,并对其发展趋势进行了展望。 相似文献
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Francesco Minto Mario Gleria Roberta Bertani Vito Di Noto Maurizio Vidali 《Journal of Inorganic and Organometallic Polymers》1998,8(2):67-88
The synthesis of a new, highly photosensitive, phosphazene copolymer containing an almost-equimolecular quantity of benzophenone and methoxyethoxyethoxy substituents is reported in this paper, together with the photochemical behavior of this material when irradiated in film both in oxygen and in an argon atmosphere. It has been detected that the photoreactivity of the phosphazene material strongly depends on the light absorption process by the benzophenone moieties, whose selective excitation predominantly brings about an intramolecular hydrogen abstraction reaction from the ethylene oxide units, thus producing highly reactive phosphazene macroradicals. The coupling reactions of these species results in the complete cross-linking of the polyphosphazene substrate and in its total insolubilization. Moreover, the influence of molecular oxygen on the overall photochemical process of the benzophenone/ethyleneoxide-substituted phosphazene copolymer is investigated. The implications of the light-induced reticulation process in the controlled insolubilization of poly[ bis (methoxyethoxyethoxy)phosphazene] are also discussed. 相似文献
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Francesco Minto Mario Gleria Roberta Bertani Vito Di Noto Maurizio Vidali 《Journal of Inorganic and Organometallic Polymers and Materials》1998,8(2):67-88
The synthesis of a new, highly photosensitive, phosphazene copolymer containing an almost-equimolecular quantity of benzophenone and methoxyethoxyethoxy substituents is reported in this paper, together with the photochemical behavior of this material when irradiated in film both in oxygen and in an argon atmosphere. It has been detected that the photoreactivity of the phosphazene material strongly depends on the light absorption process by the benzophenone moieties, whose selective excitation predominantly brings about an intramolecular hydrogen abstraction reaction from the ethylene oxide units, thus producing highly reactive phosphazene macroradicals. The coupling reactions of these species results in the complete cross-linking of the polyphosphazene substrate and in its total insolubilization. Moreover, the influence of molecular oxygen on the overall photochemical process of the benzophenone/ethyleneoxide-substituted phosphazene copolymer is investigated. The implications of the light-induced reticulation process in the controlled insolubilization of poly[ bis (methoxyethoxyethoxy)phosphazene] are also discussed. 相似文献
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Satoshi Mochizuki 《Chemical engineering science》1977,32(10):1205-1210
An effective process scheme for photochemical PCBs dechlorination reaction in alkaline isopropylalcohol has been studied. Based on the experimental obs 相似文献
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This study presents a novel technique for the controllable preparation of photoluminescent substrates to enhance the photochemical microfluidic synthesis of vitamin D_3.The dip-coating method to prepare the substrates was experimentally optimized,and the corresponding emission behaviors were systematically investigated.The substrates were successfully used to enhance the ultraviolet B(UVB) emission of a low-power light source(e.g.,an 8 W lamp),whose UVB emission intensity was increased by approximately 11 times.By virtue of the novel light source,the productivity of a single set of photochemical microreactor with a 12-meter-long channel(0.6 mm i.d.) was increased to 1.83 kg·a~(-1),which was 42% higher than that of a 100 W lamp,and no cooling devices were used.The method is simple and has great potential to replace traditional medium-pressure mercury lamps for UVB-irradiated photochemical reactions. 相似文献