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苯跟溴取代反应实验的改进 总被引:2,自引:0,他引:2
按照现行高中化学课本第二册(人教版)介绍的方法去做演示实验时,常存在如下问题:(1)实验仪器容积大,药品用量多,反应剧烈难以控制;(2)装置不密闭,不能避免苯、澳和嗅化氢蒸气对空气的污染;(3)锥形瓶上玻璃导管易下垂而插入蒸馏水中,有碍实验正常进行。现将我的改进方法介绍如下。 相似文献
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系统地研究了苯环取代烷基和侧链取代基对自位硝化反应的影响,详细地讨论了脱溴甲基的机理,多取代苯的正常硝代与自位3硝化是一对竞争反应;侧链酯基的存在是自位硝化的必要条件;苯环上取代基的空间效应是自位硝化的充分条件,六元环过滤态很可能为自位硝化反应提供了一个能量有上利的途径。 相似文献
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苯烷基取代的对苯二酚的合成 总被引:3,自引:1,他引:2
以1,4-二甲氧基苯为原料,经傅氏酰基化反应、黄鸣龙改良还原、醚键的断裂三步反应合成了3个苯烷基对苯二酚。产物的结构由元素分析、IR和^1H NMR确认。 相似文献
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人教版《化学2》中苯的溴代反应实验[1],人们已做了不少探究改进,但仍然存在一些不足[2~8]:(1)用磁铁吸引铁粉的改进方法不仅操作不方便,而且难以保证把铁屑全部吸住,稍有不慎操作就会失败;(2)装置中用直玻璃导管不利于苯和Br2蒸气的充分冷凝回流;(3)向反应后的混合物中直接注入NaOH溶液,除去未反应的Br2来观察溴苯的真实 相似文献
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Benzaldehydes bearing an electron-withdrawing group reacted with 2 equiv of benzene in the presence of a superacid, trifluoromethanesulfonic acid, to give substituted triphenylmethane in good yields. On the other hand, benzaldehydes bearing an electron-donating or a neutral group reacted under the similar conditions to give unsubstituted diphenylmethane and triphenylmethanol, together with substituted benzene. We propose a new mechanism of this reaction, which involves transalkylation as the key step. 相似文献
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氧化反应是有机化学中的一种重要反应类型,也是有机化学、化学工程和生物学家们研究的重点之一.但因其机理复杂,至今未见到用热动力学理论探索氧化反应体系的报道. N溴代丁二酰亚胺(NBS)是良好的溴化试剂,在不同反应条件下,它既可和不饱和键发生加成反应,也可在水溶液中作为次溴酸的来源,还可作为有效的氧化剂和脱氢剂.Reich和Reichstein首先报道了用N溴代乙酰亚胺将仲醇缓慢氧化为酮,Fieser等人报道了NBS的氧化作用.本文用RD-1型热导式自动量热计研究了35℃下NBS氧化异丙醇及环己醇2个反应体系,计算了反应速率常数,对反应的动力学及其机理提出了较合理的解释. 相似文献
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A facile and environmental friendly protocol for the synthesis of N-bridged fused bicyclic compounds such as imidazo[1,2-a]pyridines, imidazo[1,2-a]pyrimidines, and imidazo[2,1-b]thiazole, from commercially available starting materials has been developed. The reaction proceeds via NBS mediated in situ formation of α-brominated intermediate of corresponding aromatic ketones, 1,3-diketones, β-keto esters, followed by trapping with suitable nucleophiles to provide these versatile imidazole fused bicyclic heterocycles in good yields under metal-free conditions. 相似文献
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The L-proline-catalyzed oxidation of aliphatic primary alcohols with N-bromosuccimide (NBS) in water at room temperature to afford the corresponding dimeric esters in good to excellent yields was described. This pathway of dimeric esterification was proved to be very simple and environmentally friendly. 相似文献
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The reaction conditions employed directed the site of functionalisation of ketones with NBS: under solvent-free conditions α-bromination was the exclusive process, while in water, ring functionalisation occurred in the case of methoxy substituted aromatic ketones. 相似文献
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We found an ultraviolet (UV)-light induced formation of biphenyl and sodium benzoate from benzene and sodium carbonate. The reaction happens in the interface of benzene and aqueous solution at the room temperature. After 5 h of UV-light exposure, 11.4% of initial amount of 4.4 g (5.0 mL) benzene are converted to biphenyl and sodium benzoate, which are distributed in benzene and aqueous solution, respectively. Using density function theory (DFT) and time dependent DFT, we have investigated the mechanism of this light-induced reaction, and found that the sodium carbonate is not only a reactant for the formation of sodium benzoate, but also a catalyst for the formation of biphenyl. 相似文献
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