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《精细化工》2016,(9)
以2-溴-4-叔丁基苯酚、甲苯为原料,经叔丁基转移反应合成重要的有机中间体2-溴苯酚。该文考察了催化剂的种类、用量及反应条件对叔丁基转移反应的影响,结果表明:三氯化铝及其与叔胺盐酸盐的复合盐对叔丁基转移反应具有较好的催化活性。27Al NMR的分析表明:催化活性中心可能是三氯化铝与水解产生的氯化氢反应后形成的氯铝酸。进一步研究表明:氯化氢及溴化氢可提高三氯化铝的催化活性,降低三氯化铝的用量。优化后的工艺条件为:在二氯甲烷溶剂中,4-叔丁基苯酚与Br2在0℃反应,选择性形成2-溴-4-叔丁基苯酚,体系中n(2-溴-4-叔丁基苯酚)∶n(催化剂)∶n(甲苯)=1∶0.3∶6,于30℃"一锅法"反应制备了2-溴苯酚,其中,2-溴-4-叔丁基苯酚反应的转化率可达96.5%、2-溴苯酚的选择性达99.6%。 相似文献
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5-溴-2-甲氧基苯酚是一种重要的农药、医药中间体,本文以邻甲氧基苯酚为原料,乙酰化、溴化、脱保护得到5-溴-2-甲氧基苯酚,总收率为64.3%,产物的结构通过1HNMR、13CNMR及元素分析进行验证。 相似文献
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以对甲基苯酚为原料,经过溴化、甲基化反应,得到2-甲氧基-4甲基苯酚.在最优化条件下,得到的产品纯度>98%,产品总收率为86.5%. 相似文献
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O‐Allylations and O‐benzylations of a‐hydroxy esters ( 3a ‐ 3c ) are performed without racemization. The reagents applied, O‐allyl‐ and O‐benzyltrichloroacetimidate ( 5a , 5b ) are prepared and converted in a one‐pot‐procedure. After protection by benzylation (S)‐(‐)‐ethyl lactate ( 3a ) is converted by a sequence of carbonyl reduction, alcohol activation, ether formation, and deprotection to the optically active diglycole derivative 1a 相似文献
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2‐(4‐Nitrophenylsulfonyl)ethoxycarbonyl (Nsc) is a useful substitute for the Fmoc group. It is easily removed not only with secondary amines but with tris(aminoethyl)amine (TAEA) and with resin‐bound TAEA, thus allowing for a simplified work‐up: the side products of the deprotection are removed either by extraction with phosphate buffer or by filtration. 相似文献
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5-氨基-1-(2-羟乙基)吡唑是第4代硫酸头孢噻利的C-3位侧链。用乙氧亚甲基氰乙酸乙酯和羟乙基肼为原料,经环合、水解等一锅反应合成5-氨基-1-(2-羟乙基)-4-甲酸吡唑,然后加热脱羧得到5-氨基-1-(2-羟乙基)吡唑。分析了反应原理,优化了合成条件,提高了收率,减少了副产物的产生。 相似文献
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A. Y. Jogalekar R. G. Jaiswal R. V. Jayaram 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1998,71(3):234-240
The effect of Lewis and Brønsted acid modification on the catalytic behaviour of SnO2 was studied. Modified AlCl3, FeCl3, ZnCl2 and H2SO4 were used for this purpose. Catalytic activity was tested for Friedel–Crafts alkylation, acylation and Pechmann condensation. It was observed that the alkylation activity of SnO2 was improved upon treatment with Lewis acids and Brønsted acids. However the acylation activity was observed only when SnO2 was treated with H2SO4. Moderate improvement in the activity for Pechmann condensation reaction was observed in the case of all the modified catalysts. It was inferred that this method of modification resulted in an increase in acid strength as well as acidity of the parent oxide catalyst. © 1998 SCI 相似文献
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采用浸渍法制得Cu-Co-Ru-Mg-Cr/Al2O3催化剂,用于2-乙氧基乙醇氨化制备2-乙氧基乙胺反应;研究了反应压力、温度、空速、氨气与2-乙氧基乙醇摩尔比等因素对氨化反应的影响;在适宜的操作条件下,2-乙氧基乙醇单程转化率达到93%,2-乙氧基乙胺选择性达到95%。 相似文献