乙酰甲胺磷的工艺优化和乙酰精胺的利用

发布时间：2018-04-12 09:58

  本文选题：乙酰甲胺磷 + 乙酰精胺　； 参考：《湘潭大学》2017年硕士论文

【摘要】：乙酰甲胺磷,CAS登记名称为O,S-二甲基-N-乙酰基硫代磷酰胺,是一种新型的乙酰化有机磷杀虫剂,具有广谱高效、低毒低残留、持效期长、抗药性好等优点,相信在未来的农药市场上一定会取代甲胺磷成为大吨位品种而大放异彩。但是目前乙酰甲胺磷的生产,还是存在着反应收率低,后处理分离不彻底,会产生大量难以处理的有机磷废水,以及操作过程复杂,生产成本高等缺点。因此,对乙酰甲胺磷的合成工艺进行优化改进并对其酰化反应液中副产物的分离及回收利用,不仅具有重要的经济价值,更具有节约自然资源,减少环境污染,利于使用推广等社会价值。本论文针对乙酰甲胺磷生产工艺上的缺点,进行了详细的优化和改进。首先,在甲胺磷的异构化阶段,提出利用结晶和萃取来分离溶液中剩余10%左右未反应完全的原料精胺,以提高溶液中甲胺磷纯度和下一步酰化反应选择性。其次,在乙酰甲胺磷反应液的后处理分离步骤,针对具有腐蚀性的乙酸,采取减压蒸馏的方法,在压力-0.08MPa,温度55℃的条件下减压蒸馏1小时可以分离回收58%的乙酸,剩余的乙酰甲胺磷过饱和溶液则在适宜条件下继续结晶可以得到总收率65.83%,质量分数98.53%的乙酰甲胺磷晶体。再次,对乙酰甲胺磷反应液进行了萃取分离实验,通过有机溶剂萃取来分离酰化反应液中乙酰精胺和乙酸。实验筛选甲苯作为萃取剂,在萃取溶剂与反应液质量配比1.25:1,萃取温度45℃,萃取时间60min、静止时间90min的最优化条件下,乙酰精胺和乙酸与乙酰甲胺磷的分离系数大于1,能够被有效地萃取分离。同时为了增强萃取传质分离效果,开展了多级逆流萃取实验,实验结果表明当萃取级数为5时,乙酰精胺和乙酸分别能达到97.63%和98.77%的萃取率,分液后的萃取相和萃余相经过继续结晶,可以分别得到高纯度的乙酰精胺晶体和乙酰甲胺磷晶体。最后,对不同原料来源的乙酰精胺异构化反应进行了研究,以硫酸二甲酯为催化剂,加入原液质量分数10%~12%或18%不等的催化剂,反应3~4小时,得到的乙酰甲胺磷反应液最大收率为55%,选择性可以大于100%,为分离回收的乙酰精胺合理利用提供了依据。
[Abstract]:Cas is a new type of acetylated organophosphorus insecticide, which has the advantages of broad spectrum efficiency, low toxicity and low residue, long duration of efficacy and good resistance to insecticides, and is a new type of acetylated organophosphorus insecticide.It is believed that methamidophos will be replaced by methamidophos as a large tonnage variety in the future pesticide market.However, at present, the production of acephate still has some shortcomings, such as low yield of reaction, incomplete separation after treatment, large amount of organic phosphorus wastewater which is difficult to treat, complex operation process, high production cost and so on.Therefore, the optimization and improvement of the synthetic process of acetamidophos and the separation and recovery of by-products from acylation reaction solution not only have important economic value, but also save natural resources and reduce environmental pollution.It is beneficial to use and popularize social value.In this paper, the shortcomings of acephate production process were optimized and improved in detail.Firstly, in the isomerization stage of methamidophos, it is proposed that the remaining 10% or so unreacted spermine can be separated by crystallization and extraction in order to improve the purity of methamidophos in the solution and the selectivity of acylation reaction in the next step.Secondly, in the post-treatment and separation step of acephate reaction liquid, for the corrosive acetic acid, the method of vacuum distillation was adopted. Under the pressure of -0.08 MPA, the temperature of 55 鈩，

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