直接环合制备2-氯-5-氯甲基吡啶

2-氯-5-氯甲基吡啶是合成吡虫啉和腚虫脒等杀虫剂的关键中间体。研究了一种直接环合的方法,用2-氯-2氯甲基-4-氰基丁醛与三氯氧磷反应来制备2-氯-5-氯甲基吡啶。通过正交实验优化了反应条件,2-氯-5-氯甲基吡啶的产品纯度可以达到95%以上。     

2-氯-5-氯甲基吡啶的合成工艺路线述评

2-氯-5-氯甲基吡啶是合成吡虫啉、烯啶虫胺等多种农药及医药的关键中间体.对国内外报道的关于2-氯-5-氯甲基吡啶的合成工艺路线进行了系统的总结,并对目前开发比较成熟的工艺路线进行了综合评述,对今后合成2-氯-5-氯甲基吡啶工艺的发展方向给予客观、科学的预测.     

清洁溶剂应用于吡虫啉合成工艺中研究

以2-氯-5-氯甲基吡啶为原料,用清洁溶剂乙醇代替乙腈,采用硝基胍法对吡虫啉的合成进行了工艺改进。考察了溶剂、温度、原料配比、时间等因素对反应的影响。获得以乙醇为溶剂的最佳合成工艺条件:反应温度40℃,原料配比n乙二胺:n2-氯-5-氯甲基吡啶=2:1,反应时间为3 h,得到中间体2-氯-5-甲基吡啶乙二胺的产率为75.5%,纯度为95.30%。     

吗啉法制备2-氯-5-氯甲基吡啶

2-氯-5-氯甲基吡啶是农用杀虫剂吡虫啉、乙虫咪、烯啶虫胺和噻虫啉的重要中间体，采用吗啉法制备2-氯-5-氯甲基吡啶，具有纯度高、原材料成本低、三废少的特点，是一条值得关注的、可行的工业化路线。     

硝基胍法制备吡虫啉工艺

[目的]吡虫啉是重要的烟碱类杀虫剂,对其合成工艺进行优化。[方法]以2-氯-5-氯甲基吡啶为原料,合成出中间体N-(6-氯-3-吡啶甲基)乙撑二胺,采用硝基胍法对吡虫啉的合成工艺进行研究。考察体系pH值、温度、时间、原料配比等因素对反应的影响。[结果]在优化的反应条件下,合成最终产品吡虫啉收率达到78.0%(以硝基胍计),纯度达到98.98%。[结论]该工艺收率高、产品纯度高,适宜工业化生产。     

杀虫剂吡虫啉的合成进展

吡虫啉是一种高效、低毒、低污染、高选择性的烟碱类杀虫剂。在介绍吡虫啉性质的基础上,着重讨论了吡虫啉重要中间体2-氯-5-氯甲基吡啶的制备和吡虫啉的合成路线,同时展望了吡虫啉的市场前景。     

3种重要杀虫剂中间体的开发及产业化

介绍了毒死蜱、噻虫嗪、吡虫啉等3种重要杀虫剂中间体的合成与产业化。毒死蜱的生产工艺有环合法和吡啶法两种路线,吡啶路线是一种比较环保的工艺技术。吡虫啉的生产工艺也有吡啶衍生物路线和环合路线两种,目前我国几乎全部采用环合路线。噻虫嗪的重要中间体2-氯-5-氯甲基噻唑以环合法为主,有多条合成路线。     

3-甲基吡啶法生产2-氯-5-三氟甲基吡啶

叙述了2 -氯 -5 -三氟甲基吡啶的四种合成方法 ,着重介绍了3 -甲基吡啶法生产2 -氯 -5-三氟甲基吡啶的生产工艺及其特点。     

2-氯-5-甲基吡啶的合成研究

2-氯-5-甲基吡啶是生产烯啶虫胺、吡虫啉、啶虫咪等高效、低毒、低残留新农药的关键中间体。本文总结了2-氯-5-甲基吡啶的合成路线，评述了各路线的优缺点。     

2-氯-5-甲基吡啶的合成

2-氯-5-甲基吡啶是生产农药吡虫清、吡虫啉的重要中间体，它能降低农药吡虫啉等的原料成本。讨论了以2-氨基-5-甲基吡啶氯化法，经重氮化上氯而得的合成路线，实验讨论了反应温度、反应时间、反应物摩尔比对产品收率的影响。     

几种卤代吡啶类农药中间体的合成与应用

概述了3，5，6-三氯吡啶-2-醇、2，3-二氯吡啶、2-氯-5-氯甲基吡啶、2，3-二氟-5-氯吡啶和2，3-二氯-5-三氟甲基吡啶5种卤代吡啶类化合物的合成方法，并对其在农药工业中的应用做了简要介绍。     

吡虫啉合成的工艺优化和工业放大

In order to reduce the production cost of imidacloprid, the preparation technology for the direct combination of 2-chloro-5-chloromethylpyridine and 2-nitryliminoglyoxaline has been optimized in a 10L stirred tank reactor with a new solvent, butanone, and a new catalyst, benzyl triethyl-ammonium chloride (BTEAC), which was proved to be more profitable for the production of imidacloprid. Three main affecting factors (the reaction temperature, the molar ratio of BTEAC to 2-nitryliminoglyoxaline and the concentration of 2-nitryliminoglyoxaline) for the production of imidacloprid were investigated and the optimum operating conditions were found. Based on the above technological optimization, an industrial process for imidacloprid with a production capacity of 50 tons per year was put in operation using a 2500 L stirred tank reactor under the same operating conditions. Good yield and purity of imidacloprid was also obtained ia the industrial production.     

The Preparation of Imidacloprid in a Jet Loop Reactor

A new process for the direct combination of 2-chloro-5-chloromethylpyridine and 2-nitroiminoimidazolidine under benzyltriethylammonium chloride (BTEAC) as the catalyst and butanone as the solvent to yield imidacloprid in an 11.5 L jet loop reactor was developed. Five main reaction conditions including reaction temperature, molar ratio of BTEAC to 2-nitroiminoimidazolidine, concentration of 2-nitroiminoimidazolidine, jet liquid flow rate, and the ratio of the inside diameter of the draft tube to that of the reactor were investigated and optimized. The average molar yield and purity of imidacloprid increased to approximately 80% and 92% under the optimum operating conditions, respectively. Finally, a comparison of the efficiency for the preparation of imidacloprid between the jet loop reactor and the stirred tank reactor under the same operating conditions was conducted.     

The Preparation of Imidacloprid in a Jet Loop Reactor

A new process for the direct combination of 2-chloro-5-chloromethylpyridine and 2-nitroiminoimidazolidine under benzyltriethylammonium chloride (BTEAC) as the catalyst and butanone as the solvent to yield imidacloprid in an 11.5 L jet loop reactor was developed. Five main reaction conditions including reaction temperature, molar ratio of BTEAC to 2-nitroiminoimidazolidine, concentration of 2-nitroiminoimidazolidine, jet liquid flow rate, and the ratio of the inside diameter of the draft tube to that of the reactor were investigated and optimized. The average molar yield and purity of imidacloprid increased to approximately 80% and 92% under the optimum operating conditions, respectively. Finally, a comparison of the efficiency for the preparation of imidacloprid between the jet loop reactor and the stirred tank reactor under the same operating conditions was conducted.     

A circular microreaction method to the safe and efficient synthesis of 3-methylpyridine-N-oxide

3-Methylpyridine-N-oxide is an essential intermediate in the preparation of 2-chloro-5-methylpyridine, which can be used to synthesize nicotine insecticides such as imidacloprid and acetamiprid. The traditional method of production of 3-methylpyridine-N-oxide is catalytic oxidation of 3-methylpyridine in semi-batch reactors.Due to strong exothermic reaction and explosive property of 3-methylpyridine, the reaction efficiency and safety is low using batch technology. Therefore, the development of a safer and efficient 3-methylpyridine-N-oxide production process is very necessary in industrial production. In this paper, microreaction systems were introduced into the preparation of 3-methylpyridine-N-oxide. The comparison of three different methods(traditional semibatch method, co-current microreaction method, and circular microreaction method) showed that the circular microreaction method was the most applicable, with relative higher product yield(～ 90%), less side reaction and better reaction control.     

吡虫清的合成

吡虫清是一种氯代烟碱类优良杀虫剂。它比吡虫啉杀虫谱更广,效果更好。吡虫清的合成有四种方法。本文用２－氯－５－氯甲基吡啶经氨基化,和Ｎ－氰基乙亚胺酸乙酯反应,最后甲基化得到吡虫清。总收率为５７％（以２－氯－５－氯甲基吡啶计）,含量〉８５％。     

2-氯-5-氯甲基吡啶在气升环流反应器中的合成研究

A new process for the direct chlorination of 2-chloro-5-methylpyridine to yield 2-chloro-5-chloro-methylpyridine in an airlift loop reactor (ALR) has been studied.Five main reaction conditions including TR,na/ns,cp,Qg and dD/dR were optimized.The average molar yield and purity of 2-chloro-5-chloromethylpyridine obtained were 79% and 98.5% respectively under the optimum operating conditions.Finally,the efficiency for the preparation of 2-chloro-50chloromethylpyridine with ALR and stirred tank reactor(STR) respectively was compared.