【作者】 徐鹏；

【导师】 程振民；

【作者基本信息】 华东理工大学 ， 化学工程， 2011， 硕士

【摘要】 3,6-二氯-2-甲氧基苯甲酸(麦草畏)是一类低毒环保的除草剂。目前其制造商主要为巴斯夫以及山道士等外国公司,国内生产较少,随着绿磺隆等高毒高污染制剂的禁用和限制使用,麦草畏的市场前景良好。本文通过基团贡献法麦草畏的合成进行了热力学计算与分析,为工业生产提供理论指导；研究了工艺参数和相转移催化剂对反应的影响；研究了自吸式搅拌桨对临界转速和气液混合的影响。具体研究结果如下：(1)采用Benson、Fedors和Rozicka-Domalski基团贡献法对3,6-二氯-2-甲氧基苯甲酸甲酯合成进行热力学计算与分析,得到了反应温度在298.15-383.15K范围内时：该合成反应为吸热反应,反应吉布斯自由能变为负值,反应平衡常数值为1020数量级,从而证实该反应在热力学上是完全可行的。(2)研究O-甲基化反应工艺操作参数,发现O-甲基化最佳工艺条件为温度90℃,压力0.6MPa,搅拌速度400rpm, pH值9-10,3,6-二氯水杨酸质量100g,工艺水质量200g,甲醇质量90g。此试验条件下反应时间为7h,氯甲烷单耗为0.554,麦草畏收率在90%以上。(3)研究相转移催化剂的加入对反应的影响,发现：O-甲基化最佳相转移催化剂是三乙基苄基氯化铵,质量为5克。此试验条件下反应所需时间为4.5h,氯甲烷单耗为0.544,麦草畏收率在90%以上；并且3,6-二氯-2-甲氧基苯甲酯的水解后处理只需2小时即可完成。(4)优化自吸式搅拌桨,出气支管单侧钻孔,孔径为Φ0-Φ5,发现：改进后的自吸式搅拌桨对反应器的临界转速和气含率有显著的影响。临界转速从小到大的排序：Φ3<Φ4<Φ5<Φ2<Φ0；总气含率从大到小的排序：Φ3>Φ4>Φ2>Φ5>Φ0；釜底气含率从大到小的排序：Φ3>Φ2>Φ0>Φ4>Φ5。更多还原

【Abstract】 3,6-dichloro-2-methoxybenzoic acid is a low toxicity and environmentally friendly herbicide. At present the main producers are foreign companies. Domestic producers are very few. In this work, thermodynamic estimation for synthesis mechanism of dicamba was completed by group contribution method. Theoretical guidance was provided for industrial production; process parameters and phase transfer catalyst which had effects on the reaction was investigated; gas-inducing impeller which had effects on critical impeller speed and gas-liquid mixture was investigated. Specific results of this paper are as follows:(1)Thermodynamic estimation for synthesis mechanism of dicamba methyl ester was completed by the method of Benson, Fedors and Rozicka-Domalski group contribution. The results showed that this reaction under 298.15-383.15K is endothermic. The change of Gibbs free energy is negative and the equilibrium constant K is 1020, so the reaction is practicable in thermodynamics.(2) Process parameters of O-methylation were investigated. The study showed the optimum condition:temperature is 90℃, pressure is 0.6MPa, stirring speed is 400rpm, pH is 9-10, quality of 3,6-dichloro-salicylic acid is 100g, quality of Process water is 200g, quality of methanol is 90g. Under this test condition, the reaction time is 7h, consumption of methyl chloride is 0.554, dicamba yield is above 90%.(3)Influence of phase transfer catalyst on the reaction was investigated. The results showed that the best phase transfer catalyst is triethyl benzyl ammonium chloride. The quality is 5g. Under this test condition, the reaction time is 4.5h, methyl chloride consumption is 0.544, the yield dicamba is above 90%; and hydrolysis time of 3,6-dichloro-2-methoxy methyl ester is 2 hours.(4)Gas-inducing impeller and outlet branch were reformed. The results showed that improved self-priming impeller have a significant impact on critical speed of the reactor and gas hold-up. Critical speed in order from large to small:(Φ3＜Φ4＜Φ5＜Φ2＜Φ0; the total gas hold-up in order from large to small:Φ3>Φ4>Φ2>Φ5>Φ0; kettle emboldened rate in order from large to small:Φ3>Φ2>Φ0>Φ4>Φ5.更多还原