共查询到19条相似文献,搜索用时 156 毫秒
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综述了干法合成三氢化铝的方法.通过干法合成可以制备稳定形态的三氢化铝.和湿法合成相比,三氢化铝干法合成具有低成本、低污染和容易放大等优点. 相似文献
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以D-果糖为原料,经过内酯化反应、酰化、羰基还原、再次酰化4步反应合成2-C-甲基-α-D-呋喃核糖四苯甲酸酯(化合物 d),总收率为10.60%。采用1H-NMR、13C-NMR和MS等方法对中间产物和目标产物进行了结构表征。在2-C-甲基-D-核糖酸-1,4-内酯(a)的合成中,结合反应条件确定了最佳原料为D-果糖和氧化钙;通过对还原剂剂硼氢化钠﹑四氢化铝锂和红铝的比较,得出红铝为中间体2,3,5-三苯甲酰氧基-2-C-甲基-βD-呋喃核糖(c)合成的较优还原剂,还原收率可达96.20%;通过单因素考察确定三乙胺作为酰化反应的缚酸剂,酰化收率可达75.84%。 相似文献
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《精细与专用化学品》1995,(4)
三乙基铝具有极活泼的化学性质,与烯烃反应可得烯烃二聚体及各种α-烯烃、高碳醇和其它化学中间体;与某些过渡金属化合物构成烯烃聚合催化剂;此外可作为烷基化剂、还原剂及汽油添加剂等。 工艺技术特点:在三乙基铝存在下,铝粉直接与氢气、乙烯反应制取三乙基铝。反应分二步,第一步为氢化反应,第二步为乙基化反应。 相似文献
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合成氢化松香乙酯的新工艺研究 总被引:12,自引:0,他引:12
以DRC为催化剂,在无溶剂条件下,通过氢化松香与乙醇的直接酯化反应合成氢化松香乙酯。探索了反应温度、催化剂用量、反应时间、物料配比等因素对反应酯化率的影响,确定最佳反应条件为:反应温度180℃,催化剂用量为原料氢化松香质量的6%,反应时间6h,醇与酸的摩尔比为3:1。在最佳条件下酯化率达92.2%。还探讨了用阴离子交换树脂柱层析分离纯化氢化松香乙酯粗产物的方法。此外,利用红外光谱对氢化松香乙酯精制产物进行了表征;用GC—MS分别对氢化松香乙酯粗产物及其精制产物进行了定性和定量分析,比较了柱层析前后化学组成的变化。 相似文献
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《精细化工》2013,(11)
以D-果糖为原料,经过内酯化反应、酰化、羰基还原、再次酰化4步反应合成1,2,3,5-四-O-苯甲酰基-2-C-甲基-β-D-呋喃核糖(化合物d),总收率为10.60%。采用1HNMR、13CNMR和MS对中间产物和目标产物进行了结构表征。在2-C-甲基-D-核糖酸-1,4-内酯(a)的合成中,结合反应条件确定了最佳原料为D-果糖和氧化钙;通过对还原剂硼氢化钠、四氢化铝锂和红铝的比较,得出红铝为中间体2,3,5-三苯甲酰氧基-2-C-甲基-β-D-呋喃核糖(c)合成的较优还原剂,还原收率可达96.20%;通过单因素考察确定三乙胺作为酰化反应的缚酸剂,酰化收率可达75.84%。 相似文献
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Kinetic aspects of self-discharge of nickel-hydrogen batteries and methods for its prevention 总被引:1,自引:0,他引:1
A. Visintin A. Ananit S. Srinivasan A. J. Appleby H. S. Lim 《Journal of Applied Electrochemistry》1995,25(9):833-840
Results of microcalorimetric experiments, in relation to self-discharge in Ni/H2 batteries are reviewed; the mechanism of self-discharge, as well as possible methods for its inhibition, are discussed. These studies indicate that: (i) the self-discharge is due to a direct reaction of hydrogen with the charged active material (nickel oxide); (ii) the presence of metallic nickel sinter particles does not affect the reaction rate; (iii) the reaction rate depends linearly on hydrogen pressure indicating that the reaction is first order with respect to hydrogen; (iv) the reaction rate is higher under starved-electrolyte rather than flooded electrolyte conditions, indicating that the rate is affected by a diffusion process of dissolved hydrogen; and (v) the microcalorimetric heat evolution rate correlates with that of a decrease in electrode capacity due to the self-discharge reaction. The effects of additives to the active material of the nickel electrode were tested as an approach to reduction of the intrinsic rate of self-discharge. An alternate method for minimizing this rate is by storing the hydrogen as a hydride and thereby lowering the cell operating pressure. Some alloys were thus examined for their hydriding/dehydriding characteristics. 相似文献
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A. M. Dubinin V. G. Tuponogov I. S. Ikonnikov 《Theoretical Foundations of Chemical Engineering》2013,47(6):697-701
Using the chemical reactions that accompany the production of syngas via the steam reforming of methane as a basis, the differential material balance equations were derived and solved for all conversion products on an aluminum/nickel catalyst. For the following stage of hydrogen synthesis on an iron/chromium catalyst, the system of two differential equations of the material balance of the direct and reverse reactions of steam carbon monoxide conversion was obtained and solved. The analytical solutions were compared with the experiment. 相似文献
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氢能作为一种环保可再生的新型能源,生产技术逐渐走向成熟,成本大幅度下降,将迎来快速发展的机遇期。氢能被广泛利用的关键在于是否能够实现高效储存。本文重点讨论了四类新型储氢材料,即金属络合氢化物储氢材料、碳纳米管储氢材料、沸石以及新型沸石类材料、有机液态储氢材料。文章指出:金属络合氢化物储氢材料储存压力低但循环稳定性差;碳纳米管储氢材料已经有很长的发展历史,安全性高且易脱氢,然而目前对其储氢机理认识不够成熟;沸石以及新型沸石类材料价格低廉,但是对反应条件的要求高;有机液态储氢材料被认为是大规模储存和运输的可行选择,然而昂贵的成本和苛刻的反应条件限制了其发展。文章指出后续需要改进并开发具有较高存储容量和具有经济价值的储氢材料。 相似文献
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A procedure for direct conversion of long chain triglycerides to their corresponding ether derivatives has been accomplished using a combination of lithium aluminum hydride and boron trifluoride etherate. Reaction products obtained from reduction of tristearin or trimyristin were isolated by thin layer and column chromatography and identified using infrared spectroscopy. Glyceryl triethers, glyceryl monoethers, and aliphatic alcohols were the major reaction products, making up 2–3%, 9–19%, and 43–75%, respectively, of the theoretical molar yields. Yields of both ether derivatives were increased when a lithium aluminum hydride solution was added to a mixture of triglyceride and boron trifluoride etherate rather than adding a mixture of triglyceride and boron trifluoride etherate to lithium aluminum hydride. Increasing the quantities of lithium aluminum hydride increased glyceryl triether yield, but decreased glyceryl monoether yield. 相似文献
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Kohji Nagashima Heidy Visbal Kazuyuki Hirao Hitoshi Ishizaka Akira Kamisawa 《International Journal of Applied Ceramic Technology》2016,13(2):265-268
The on‐site type hydrogen generator was developed. Among the various hydride materials, calcium hydride (CaH2) was selected as hydrogen source because of less reactivity with moisture compared to other alkaline hydride compounds. By mixing CaH2 with the thermosetting resin, inorganic–organic hybrid material was prepared. Pure CaH2 reacts vigorously with water to form hydrogen gas and Ca(OH)2, while this hybrid material moderately produces hydrogen by reacting with water keeping high reaction rate. 相似文献