2,5-二氯苯酚的合成新工艺研究 精细化工专业

- -I摘 要麦草畏，商品名百草敌或百草畏，化学名为 3,6-二氯-2-甲氧基苯甲酸，纯品为白色晶体，是一种高效内吸传导型的除草剂，主要用于旱地农作物除草。主要几种不同的制备方法，工业生产中应用最广泛的为 3,6-二氯水杨酸醚化制备麦草畏的方法。2,5-二氯苯酚是 3,6-二氯水杨酸制备中重要的原料。通常由 2,5-二氯苯胺重氮化后酸性条件下水解制得，也可由 1,4-二氯苯催化氧化制得，此外还有 1,2,4-三氯苯碱性醇解等方法。2,5-二氯苯酚在精细化工生产中有重要应用，除用作除草剂麦草畏的中间体，还应用于医药、染料等其他领域，在氮肥增效、皮革防腐方面有着重要的应用。本文以 2,5-二氯苯胺重氮化水解制备 2,5-二氯苯酚为基础，改进合成工艺，以盐酸代替传统硫酸制备重氮盐，对硫酸与原料配比、反应温度、亚硝酸钠的用量等反应条件进行优化，并尝试催化氧化方法合成 2,5-二氯苯酚。当 2,5-二氯苯胺与硫酸摩尔比达到 5：2，反应温度为 145℃，亚硝酸钠与原料摩尔比为 1.6-1.8 之间，常规蒸馏可得到 92.4％的收率，高效液相色谱分析纯度为 97.5％。关键词：麦草畏；2,5-二氯苯胺；2,5-二氯苯酚；2,5-二氯苯甲醚 - II -2,5-二氯苯酚的合成新工艺研究The Study on Synthesis of 2,5-Dichlorophenol Abstract Dicamba, which trade name is Banvel and chemical name is 3,6-dichloro-2-methoxy- benzoic acid. Dicamba is a kind of high efficiency in the absorption of the type of herbicide, and it is mainly used for drill and crop weeding. There are several major methods of preparation. In industrial production, the most widely used methods is etherifying 3,6-dichlorosilicylic acid to produce Dicamba.2,5-dichlorophenol is an important starting material to prepare 3,6-dichlorosalicylic acid. Generally use the methods of diazotizing and hydrolyzing 2,5-dichloroaniline to produce Dicamba. 1,4-Dichlorobenzene can be also oxidized to 2,5-dichlorophenol. In addition to that, the method of using 1,2,4-trichlorobenzene to occurs alcoholysis reaction in alkaline environment is also used.2,5-dichlorophenol in fine chemical production has import...