甲基亚磷酸二乙酯合成草铵膦工艺的研究

发布时间：2018-04-03 17:26

本文选题：氢氰酸　切入点：甲基亚磷酸二乙酯　出处：《河北大学》2017年硕士论文

【摘要】：草铵膦是由联邦德国Hoechst化学公司首先开发的一种有机磷除草剂。其除草作用机理是通过作物的叶片吸收后,经过内吸作用,然后再由叶片的基部逐渐向端部进行转移。草铵膦对未出土的幼牙和种子无害,且容易降解,因此成为在国内和国外都非常受欢迎的一种除草剂。目前国内生产草铵膦的主要工艺路线是以亚磷酸三乙酯为原料,与三氯化磷生成一氯亚磷酸二乙酯、再经与格氏试剂反应生成关键的中间体甲基亚磷酸二乙酯。然后甲基亚磷酸二乙酯经过缩醛反应、解缩反应、解缩产物与氰化钠和氯化铵进行strecker反应、氰基水解反应和氨化反应等复杂的反应步骤和产品提纯步骤最终生成草铵膦成品。此工艺虽然成熟,但存在两个问题:第一,缩醛必须经过解缩后才能进行strecker反应,解缩后产物须进行精馏,合成和操作步骤长,操作繁琐,增加了生产成本。第二,strecker反应中氰化钠的使用,导致副产氯化钠和氯化铵混盐,给企业额外增加了环保压力。本文研究的甲基亚磷酸二乙酯为原料制备草铵膦的工艺,是一种生产成本低,对环境友好的路线,因此本课题的开展对草铵膦的合成方法有很强的指导意义。本文研究了甲基亚磷酸二乙酯为原料制备草铵膦的工艺。重点对草铵膦收率起到关键影响的缩酯反应进行了研究,通过大量实验研究最终确定了较优的工艺,减少了解缩反应步骤及膦醛精馏操作,大大缩短了反应时间,提高了生产效率和降低了生产成本;采用氢氰酸为原料替代氰化钠进行strecker反应,避免了副产氯化钠和氯化铵混合盐问题,通过对副产氯化铵进行处理,实现了循环利用,彻底解决了环保副产盐的问题,通过正交试验设计最终确定了氢氰酸为原料进行strecker反应制备氨基腈的工艺条件;对氨基腈制备草铵膦步骤进行了一定的探讨,通过盐酸盐精制和氨化反应终点的严格控制,最终得到了98%以上的高品质的草铵膦,收率为85%左右。
[Abstract]:Ammonium phosphine is an organophosphorus herbicide first developed by Hoechst Chemical Company of Germany.The mechanism of herbicidal action is that it is absorbed through the leaves of the crop, and then transferred gradually from the base of the leaf to the end.Phosphine oxalate is a very popular herbicide at home and abroad because it is harmless to unexcavated young teeth and seeds and easy to degrade.At present, the main process of producing ammonium phosphine in China is to produce diethyl monochlorite from triethyl phosphite and phosphorus trichloride, and then react with Grignard reagent to form the key intermediate methyl diethyl phosphite.Then diethyl methylene phosphite was synthesized by acetal reaction, decompression reaction, strecker reaction with sodium cyanide and ammonium chloride, hydrolysis of cyanide and ammoniation reaction, and purification steps of the product to form the finished product of ammonium oxalate and phosphine.The use of sodium cyanide in the second strecker reaction led to the by-product of sodium chloride and ammonium chloride mixed salt, which increased the pressure of environmental protection.The process of preparing ammonium phosphine from diethyl methyl phosphite in this paper is a low cost and environmentally friendly route. Therefore, the development of this topic has a strong guiding significance for the synthesis of ammonium phosphine.In this paper, the preparation of ammonium phosphate from diethyl methyl phosphite was studied.The esterification reaction which has a key effect on the yield of ammonium phosphine was studied in this paper. Through a large number of experimental studies, the optimum process was determined, and the steps of the shrinkage reaction and the rectification operation of phosphonaldehyde were reduced, and the reaction time was greatly shortened.The production efficiency was improved and the production cost was reduced, the strecker reaction was carried out by using hydrocyanic acid as the raw material instead of sodium cyanide, the problem of mixed salt of by-product sodium chloride and ammonium chloride was avoided, and the by-product ammonium chloride was treated to realize recycling.The problem of producing salt by environmental protection was solved thoroughly, and the process conditions for the preparation of aminonitrile by strecker reaction of hydrocyanic acid as raw material were determined by orthogonal design, and the steps of preparing ammonium phosphine from aminonitrile were discussed.Through the strict control of the end point of the reaction of hydrochloric acid and ammoniation, more than 98% high quality ammonium phosphine was obtained, and the yield was about 85%.
【学位授予单位】：河北大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ457.29

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