共查询到19条相似文献,搜索用时 359 毫秒
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3,5-二硝基苯甲酸经还原和碘化两步反应得到造影剂泛影酸关键中间体3,5-二氨基-2,4,6-三碘苯甲酸(碘化物),总收率约70.4%。该工艺反应条件温和,易于操作,对环境污染较少,是一条适于工业化生产的合成路线。 相似文献
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以不同碱金属(铵)卤化物为催化剂,考察了其在二氧化碳与甘油合成甘油碳酸酯反应中的活性。采用环氧丙烷为溶剂及耦合剂,极大提高了反应的转化率。实验结果发现碘化物具有较好的催化活性。以碘化铯为催化剂,考察了反应温度、反应时间、反应压力、反应物摩尔比和催化剂用量对反应结果的影响。在最佳反应条件下(环氧丙烷0.3 mol,甘油0.1 mol,反应温度120℃,反应时间1.5 h,反应压力3.0 MPa,催化剂用量0.15 g),甘油的转化率为86.5%,甘油碳酸酯的产率为81.6%。 相似文献
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以邻甲苯胺为起始原料,高碘酸钠为氧化剂,单质碘取代得2-氨基-5-碘甲苯,再经重氮化及Gattermann反应,得2-溴-5-碘甲苯,总收率66.1%(以邻甲苯胺计)。结果表明,较佳的工艺条件为:碘化过程中邻甲苯胺、高碘酸钠和碘的摩尔比为1∶0.6∶0.45,反应温度为25~30℃,反应时间3 h;在重氮化、溴代反应中,以亚硝酸钠为重氮化试剂,2-氨基-5-碘甲苯与亚硝酸钠和浓硫酸的摩尔比为1∶1∶7.5,反应温度为0~5℃,溴代反应时间为0.5 h;经精馏所得产物含量超过98%(GC法)。改进后的工艺原料易得,操作简便,适合工业化生产。 相似文献
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《精细化工原料及中间体》2018,(9)
正本发明公开了一种3,5-二碘-4-氨基吡啶原位生成碘代试剂合成方法,以4-氨基吡啶、碘化盐、碘酸钾、亚氯酸钠为主要反应原料。反应过程中,氧化剂缓慢将碘化盐氧化为反应需要的碘,即原位生成碘的方式反应得到目标产物3,5-二碘-4-氨基吡啶。与现有公开技术相比,该工艺路线具有反应选择 相似文献
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The kinetic study of the iodination of cinnamaldehyde and furfuraldehyde with hydrated monopositive iodine, produced by the interaction of aqueous I2 solution and Ag+ at μ = 0.3 (NaClO4) was followed potentiometrically by using platinum gauge and saturated calomel electrode assembly. The reactions are of the first order with respect to both the substrate concentration (cinnamaldehyde and furfuraldehyde). They are also first order with respect to hydrated monopositive iodine, the iodinating agent. The reactions are independent of [Ag+] and [H+] in the solution in which the reactions have been studied. 相似文献
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Hydrochloric acid activates the oxidative iodination of aromatic compounds with the iodine‐ hydrogen peroxide system through the formation of an iodine(I) compound as the iodinating reagent. Activation with hydrochloric acid is more powerful than that with sulfuric acid. The formation of dichloroiodic(I) acid (HICl2) with various forms of hydrogen peroxide was followed using UV spectroscopy. The HICl2 was used as the iodinating reagent. In the preparative oxidative iodinaton of various aromatic compounds, hydrochloric acid was used in a catalytic amount and the iodine(I) reagent was formed in situ with 0.5 equiv. hydrogen peroxide and 0.5 equiv. molecular iodine. Two types of reactivity were observed in oxidative iodination with iodine(I) species catalyzed by hydrochloric acid: in the iodination of anisole 1a better yields of iodination were observed with a smaller amount of hydrochloric acid, while on the contrary 4‐tert‐butyltoluene 1b gave better yields of iodination upon increasing the amount of hydrochloric acid. Reactivity was further manipulated by the choice of the solvent (MeCN, trifluoroethanol, hexafluoro‐2‐propanol). 相似文献
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以联苯和碘为原料,采用直接碘化法合成了4,4′-二碘联苯。重点考察了物料配比、反应介质中水量、催化剂种类、温度对反应的影响。优化的工艺条件为:n(联苯)∶n(碘)∶n(过硫酸铵)=1∶1.1∶1.1,反应介质为冰乙酸和水,催化剂为浓硫酸,反应温度为85℃,产品收率为86.21%。 相似文献
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