【作者】 刘启发；

【导师】 陆明；

【作者基本信息】 南京理工大学 ， 应用化学， 2010， 博士

【摘要】 在有机合成中,芳环化合物的氯甲基化和将苄基卤氧化成芳醛或芳酮是一类极其重要的反应。研究和开发出简单、经济、环境友好的新方法无论在实践还是理论方面都具有重要的意义。本课题主要研究了在水介质中实施芳环化合物的氯甲基化和苄基卤的氧化反应,以期开发出对环境友好的氯甲基化和氧化反应的新方法,具体的研究内容包括以下几个方面。在实施2-溴乙基苯氯甲基化反应的胶束体系中加入少量的电解质,研究了电解质对胶束催化反应的影响规律。结果表明,在表面活性剂的胶束溶液中,电解质的加入能引起临界胶束浓度（CMC）的下降和2-溴乙基苯增溶量的增大。在外加电解质的胶束中进行氯甲基化反应能显著提高2-溴乙基苯的转化率和单氯甲基化产物的选择性。通过比较阴、阳离子和非离子表面活性剂对胶束催化反应的效果,研究了胶束催化氯甲基化反应的机理及外加电解质与三种表面活性剂的协同机制。为适应工业化生产的需要,在反应底物远远超过胶束的最大增溶量的两相体系中实施了芳环化合物的氯甲基化反应。考察了阳离子表面活性剂的结构对反应的影响规律。进一步研究了胶束催化氯甲基化反应的机理。实验结果表明,胶束催化是实现芳环化合物氯甲基化的有效方法。氯甲基化反应由亲电取代反应和亲核取代反应组成,亲核取代反应是反应的速率控制步骤,羟甲基碳正离子（⁺CH₂OH）;是真正有效的亲电试剂。阳离子表面活性剂,特别是含有较长疏水链的阳离子表面活性剂是最为有效的催化剂。在两相胶束催化体系中,芳环化合物的单氯甲基化产物的选择性得到显著的改善,反应的区域选择性由表面活性剂的本质决定。在最佳的反应条件下,异丙苯氯甲基化反应的转化率为89.8%,单氯甲基化选择性为97.5%,para/ortho选择性可达到8.28。发明了一种在氢氧化钾（KOH）水溶液中相转移催化苄基卤的硝酸钾（KN03）氧化的新方法。研究了氧化反应机理和考察了各种因素对氧化反应的影响。研究发现,相转移催化剂能够高效的催化苄基卤的KN03氧化,并能高产率的得到氧化产品。氧化反应由亲核取代反应和α-消除反应组成,α-消除反应是反应的速率控制步骤。含有较长疏水碳链的相转移催化剂是较为有效的催化剂。发展了一种TEMPO/KNO₂催化分子氧氧化苄基卤成醛或酮的新方法。考察了各种因素对氧化反应的影响,研究了氧化反应的机理。研究表明TEMPO/KNO₂只能在水介质中高效地催化分子氧将苄基卤氧化成芳醛或芳酮,并高产率的得到氧化产品。氧化反应由苄基卤的水解反应和水解产生的苄基醇的氧化反应组成,苄基卤的水解反应是反应的速率控制步骤。更多还原

【Abstract】 In organic synthesis, chloromethylation of aromatic compounds and oxidation of benzylic halides to aromatic aldehydes or aromatic ketones are extremely important reactions. Therefore, the development of a simple, economic, and eco-friendly method is of great significance in both in practice and in theory.The main objective of this dissertation is to perform the chloromethylation reaction of aromatic compounds and the oxidation reaction of benzylic halides in aqueous media with a view to develop new environment-feiendly methods, and the specific research contents include the following aspects.A small amount of electrolyte was added into the micellar catalysis system in which chloromethylation reaction of 2-bromoethylbenzene （BEB） was carried out, and the effect of electrolyte on the catalytic reaction was investigated. The decrease in critical micelle concentration （CMC） and the increase in solubilization of BEB in the micelles formed by surfactant and electrolyte were observed. The chloromethylation reaction of BEB exhibited higher conversion and higher selectivity in mono-chloromethylation in the surfactant micelles containing electrolyte than in the single surfactant micelle. The catalysis effects of anionic, cataioic and non-ionic surfactants were compared; the mechanism of chloromethylation reaction and the synergistic mechanism between electrolyte and three types of surfactants were discussed.For the purpose of industrutial production, the chloromethylation reaction of aromatic compounds was performed successfully by micellar catalysis in oil/water biphasic system at high reactant loadings that exceeded the maximum solubilization capacity of micellar solutions. The effects of the structures of cationic surfactants on the reaction were compared. The mechanism of chloromethylation reaction and the mechanism of micellar catalysis were further investigated. The results show that the micellar catalysis is an effective way to realize the chloromethylation. The chloromethylation reaction consists of electrophilic substitution reaction and nucleophilic substitution reaction, the nucleophilic substitution is the rate-controlling step and the hydroxymethyl cation （⁺CH20H） is the really effective electrophile. Cationic surfactants, especially those containing longer hydrophobic carbon chain, are more effective. Selectivity for mono-chloromethylation was remarkably improved and regioselectivity was found to be dependent on the nature of the surfactant. Under the optimal reaction conditions, chloromethylation of isopropylbenzene could obtain 97.5% selectivity in mono-chloromethylation and 8.28 para/ortho selectivity ratio at 89.8% conversion.A new procedure of phase transfer catalyzed oxidation of benzylic halides to aldehydes or ketones with potassium nitrate （KNO₃） in aqueous potassium hydroxide （KOH） solution has been developed. The oxidation mechism and the effects of different factors on the oxidation reaction were examined. The results show that the phase transfer catalysis is an effective way to realize the oxidation of benzylic halides to aldehydes or ketones with KNO₃ in high yield. The oxidation reaction consists of nucleophilic substitution reaction and a-elimination reaction which is the rate-determining step. Phase transfer catalyst having longer hydrophobic carbon chain, is more effective catalyst.A new method by which benzylic halides are directly oxidized to aldehydes and ketones with molecularr oxygen （O₂） in the presence of catalytic amounts of TEMPO （2,2,6,6-tetramethylpiperidyl-l-oxy） and potassium nitrite （KNO₂） has been developed. The oxidation mechism and the effects of different factors on the oxidation reaction were investigated. The experimental results show that, only in aqueous media, TEMPO/KNO₂ can catalyze the oxidation of benzylic halides to aldehydes or ketones with O₂ in high yield. The oxidation reaction was composed of hydrolysis reaction of benzylic halides and oxidation reaction of the resulting benzylic alcohols. The hydrolysis of benzylic halides is the rate-determining step.更多还原