共查询到19条相似文献,搜索用时 62 毫秒
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以单体双-(3-甲氧基-4-羟基苄叉)-4,4'-二亚胺基苯与a,ω-二溴烷,采用相转移催化聚醚化法合成7种主链型液晶聚甲亚胺醚,用^1H NMR、IR、UV、元素分析及热台偏光显微镜、DSC和WAXD对聚合物的结构和液晶行为进行了表征。熔点和清亮点随间隔基数(n)改变,并有奇偶效应,呈现锯齿形变化规律。 相似文献
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聚乙二醇相转移催化羧酸酯的合成谢筱娟,杨高升,杨富国,宋雪清(安徽师范大学化学系芜湖241000)关键词聚乙二醇,相转移催化,酰化反应,羧酸酯通常羧酸酯的制备是利用醇与羧酸、酰氯或酸酐反应,但这个方法对有立体位阻的醇不太适宜[1],为此,为寻找好的方... 相似文献
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相转移催化法合成1—甲基—3,5—二苯基吡唑 总被引:1,自引:0,他引:1
1-甲基-3,5-二苯基吡唑是合成防除野燕麦药剂——野燕枯(1,2-二甲基-3,5-二苯基吡唑硫酸甲酯盐)的重要中间体,其合成方法文献 相似文献
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聚氯乙烯多乙烯多胺树脂催化合成硫氰酸苄酯 总被引:3,自引:1,他引:2
在含有聚氯乙烯-多乙烯多胺树脂的乙醇中,氯化苄在78℃与硫氰酸钾反应5小时,得到97.3%收率的硫氰酸苄酯,此法操作简便,催化剂容易分离并能重复使用。 相似文献
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添加剂对非离子十二烷基聚氧乙烯聚氧丙烯醚浊点的影响 总被引:10,自引:2,他引:10
测定了无机盐、单元及多元醇、有机酸及离子型表面活性剂对3种非离子表面活性剂十二烷基聚氧乙烯聚氧丙烯醚C12H25(EO)m(PO)nH(LS36,m=3,n=6;LS45,m=4,n=5;LS54,m=5,n=4)浊点的影响. 相似文献
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聚氧烯醚嵌段聚合物及其硬脂酸酯类表面活性剂作为优良的消泡剂用于抗生素、谷氨酸发酵和其它行业中[1~4]。作者曾研究过一些聚氧烯甘油的消泡效力[5~6]。证明以二硬脂酸酯(GPES-2)的消泡效力最高[7]。本文研究的是GPE和GPES-2分子中亲水基(聚氧乙烯基,EO)的含量及亲水亲油平衡值(HLB)与消泡效力的关系。 相似文献
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12-钨磷酸催化合成甲基叔丁基醚 总被引:3,自引:0,他引:3
甲基叔丁基醚(MTBE)作为汽油抗暴剂已经在全世界范围内普遍使用,它不仅能提高汽油辛烷值,而且还能改善汽车性能,降低排气中CO和有机物含量,同时降低汽油生产成本. 相似文献
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丙二酸甲(乙)烷酯类是一些药物和天然产物合成的中间体,一般由丙二酸二甲(乙)酯经部分水解得到丙二酸单甲(乙)酯钠盐,再通过酸化、酰氯化和酯化反应制得[1],该方法路线较长、酰氯化反应会产生有毒尾气。羧酸(包括烷酸和芳酸)酯可由其盐和卤代烃直接反应制得[2-4],而且可利用无溶剂相转移催化的条件进一步加速反应和提高产率。微波技术用于有机合成[5-7]具有操作简便、产率高和速度快等优点。我们参考文献[2-4]方法,应用微波技术合成了标题化合物。1 实验部分1 1 仪器BrukerDPX 300FT NMR型核磁光谱仪,TMS为内标;IR… 相似文献
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Bhajendra N. Barman Donald H. ChampionStephen L. Sjoberg 《Journal of chromatography. A》2009,1216(40):6816-6823
Quantitative determination of polyethylene glycol (PEG) impurities in two monofunctional polyglycol types, PEG methyl ether (M-PEG) and PEG vinyl ether (V-PEG), has been carried out by reversed-phase liquid chromatography with evaporative light scattering detection (ELSD). In addition to optimizing the resolution between PEG and monofunctional PEG peaks, the major focus has been to determine the molecular weights of PEG impurities in M-PEG and V-PEG of diverse molecular weights. The latter is achieved by examining liquid chromatography–mass spectrometry (LC–MS) mass spectra of both monofunctional PEG and PEG in several cases, and matching peak retention times with those of available PEG standards for all M-PEG and V-PEG sample types. This information is helpful in selecting the appropriate PEG standard to determine PEG content in each sample type. ELSD response factors for various PEG standards have also been compared. It has been found that PEG standards with molecular weights from 1000 Da to 8000 Da show responses that are within 10% of each other. However, a low molecular weight PEG such as PEG 400, provides approximately 30% less response compared to its higher molecular weight counterparts. 相似文献
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N. G. Komissarova N. G. Belenkova O. V. Shitikova L. V. Spirikhin M. S. Yunusov 《Russian Chemical Bulletin》2005,54(11):2659-2663
The addition of dichlorocarbene generated under phase transfer catalysis conditions to the double bond of betulonic acid occurs
stereoselectively and is accompanied by transformation of the carboxy group leading to the dichloromethyl ester and chloride
of 3-oxo-20,29-(dichloromethano)lupan-28-oic acid. Together these products, the chloride of the starting betulonic acid is
formed depending on the reaction conditions. The reaction of dichlorocarbene with methyl betulonate leads to the corresponding
cyclopropane adduct in a quantitative yield.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2574–2578, November, 2005. 相似文献
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The reactions of oximes with benzyl bromide catalyzed by benzyldimethyltetradecylammonium chloride are carried out at room
temperature for 30–60 min in aqueous sodium hydroxide solution under ultrasound irradiation to offer O-benzyl oxime derivatives
in 60–96% yields. In comparison to classical methods, the advantages of the present procedure include short reaction time,
high yields and environmental friendliness.
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Translated from Chinese Journal of Organic Chemistry, 2008, 28(4) (in Chinese) 相似文献