管道化合成间溴苯酚新工艺

New technology for synthesis of m-bromophenol with tubular reactor

为了解决间溴苯酚在传统釜式生产过程中的返混而造成的偶合副反应问题,采用管道化方式进行间溴苯酚的合成.以间溴苯胺、硫酸和亚硝酸钠为原料,通过重氮化和水解反应合成间溴苯酚.采用管式反应器替代釜式反应器克服了由于产物与重氮盐返混而造成的偶合副反应,从而提高了水解反应的选择性.水解产物经甲苯萃取再经减压精馏进行精制,所得产品的纯度及化学结构由气相色谱和红外光谱分析与鉴定.产品收率为91%,纯度达到99%以上.主要考察了管式反应器中滴加速度对该反应的影响,结果表明,当滴加速度为8 mL/min时得到最高的反应收率,反应中水解反应液可以套用7次.

The tubular reactor was adopted in the synthesis of m-bromophenol to solve the feed-back problem and depress the side reactions in the traditional batch reactor, m-bromophenol was prepared by diazotization with m-bromoaniline, sulfuric acid and sodium nitrite as raw materials and hydrolysis. With the replacement of the traditional batch reactor by the tubular one, the side reactions of the conjunction of the target product with the unconverted intermediate diazotium are depressed effectively. Thus, the selectivity of the hydrolysis is enhanced. The hydrolysis product was extracted with toluene and then distilled under vacuum. The purity and chemical structure of the result product were identified by gas chromatography and IR, respectively. The yield of the product reached 91% while more than 99% of the purity. The effect of the dropping pace in the tubular reactor on the yield was mainly studied, and the result suggested that the yield reached a highest point at a dropping pace of 8 mL/min and the hydrolysis solution could be reused for 7 times.