2,6-二乙基甲叉苯胺的合成

2,6 二乙基甲叉苯胺是酰胺类除草剂的重要中间体,其质量的好坏影响最终产品的纯度和收率。在碱催化下,多聚甲醛与乙醇形成醛醇络合物,再与2,6 二乙基苯胺反应。采用管式反应器进行合成,在反应体系中加入二甲苯作溶剂,通过共沸减压蒸馏蒸出乙醇和反应生成的水,体系中水的含量小于0 005mol/L时,反应可以结束。收集104～105℃/7277Pa馏分,通过气相色谱分析测定产品纯度w(2,6 二乙基甲叉苯胺)>98%。

Synthesis of 2,6-Diethylphenylazomethin

2,6-Diethylphenylazomethin(Ⅰ) is the important intermediate of N-alphahaloalkylanilide herbicide.Its quality is key to the purity and yield of the end-product.High-grade Ⅰ can be made by reaction of 2,6-diethylaniline in a tubular reactor with a formaldehyde alcohol complex,gotten by contacting parafomaldehyde with alcohol in the presence of catalytic amount of a base.The reaction is carried out in xylene solvent,which forms an azeotrope with alcohol and the water of reaction during vacuum distillation.The reaction is completed when the moisture content of the distillate is less than 0.005 mol/L.Ⅰ was collected under a pressure of 7277 Pa at 104～105 ℃.The purity can reach 98% by gas-chromatographic analysis.