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【答案】应助回帖
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南桥小流: 金币+80, 翻译EPI+1, ★★★很有帮助, 很犀利的翻译，小弟不胜感激， 2012-04-03 17:06:52
Mally89: 金币+2 2012-04-03 21:20:50
化合物专业名称没问题，工艺名称没问题的前提下，试修改如下：
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As a new type of neonicotinoid insecticide, clothianidin has characteristics of high efficiency，low toxicity，environment-friendly and broad insecticidal spectrum．It has been promoted in many countries and regions in recent years. The test application results of it in some areas in China have showed that the effectiveness is significant．There will be a great demands for the product in domestic market for its performance. However, the synthetic technology of the product is not perfect for industrialization in China. In order to reduce the cost of production and to lay a firm foundation for industrialization of the product, we have optimized the process conditions by experiments. The main works of the research are summarized as follows：
1．We use 2,3-dichloropropene，sodium thiocyanate as primary materials to get 5-aminomethyl-2-chlorothiazole by substitute, addition, losed loop, elimination reactions. We have obtained a optimum process conditions for synthesis of 5-aminomethyl-2-chlorothiazole. The procedures are：(1) to get 1-isothiocyanate-2-chloro-2-propylene from 2,3-dichloropropene and sodium thiocyanate (with molar ratio of 1:1) at 80℃ for 8 hours; (2) to get 2-chloro-5-chloromethylthiazole from 1-isothiocyanate-2-chloro-2-propylene and sulphonyl chloride (with molar ratio of 1:1.05) at 45 ℃ for 3 hours; (3) to get 5-aminomethyl-2-chlorothiazole from 2-chloro-5-chloromethylthiazole and ammonia (with molar ratio of 1:5) at 70℃ for 4 hours. The purity of the product is 98% and the yield is 62.6%．The final product is 5-aminomethyl-2-chlorothiazole confirmed by means of 1HNMR，LC-MS and IR spectra.
2．O-methyl-N-–nitroisourea is prepared from urea and dimethyl sulfate by methylation and nitration process. The optimum conditions for the synthesis process are: the molar ratio for urea and dimethyl sulfate is 1.3:1, reaction temperature is 70 ℃, and reaction time is 4 hours. The purity of the product is 99% and the yield is 43%, and the product is also confirmed by means of 1HNMR，LC-MS and IR spectra．
3．O-methyl-N-(2-chloro-5-thiazolylmethyl)-N'-nitroisourea is synthesized with prepared 5-aminomethyl-2-chlorothiazole and O-methyl-N-nitroisourea, then reacts with methylamine to get the objective clothianidin (chemical name is 1-(2-chloro-5-thiazolymethyl)-3-methyl-2-nitroguanidine)．Ratio 1:1.1 for 5-aminomethyl-2-chlorothiazole and O-methyl-N-nitroisourea , room temperature, 8 hours are considered the optimum conditions for the synthesis of O-methyl-N-(2-chloro-5-thiazolylmethyl)-N'-nitroisourea．The purity of the final product reaches 98% and the total yield for the two processes is 65.1%, and the final product is confirmed by means of 1HNMR，LC-MS and IR spectra.
4．Clothianidin can be obtained from 2,3-dichloropropene, urea, methylamine, etc. by several synthesis processes. The total yield can reach 40.7% (calculated from raw materials 2,3-dichloropropene). The optimized process has advantages of mild reaction conditions and lower cost etc., and has a perspective future for industrialization. |
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