3,4-二乙氧基硝基苯精制技术研究

3,4-二乙氧基硝基苯是生产杀菌剂乙霉威的中间体,工业制备方法是将邻苯二乙醚和溶剂加入反应釜中,开搅拌控制一定温度滴加65%硝酸,反应结束降温过滤得粗品,粗品含量低且包酸及有机杂质(氧化产物),文章采用10%碳酸钠水溶液洗涤该粗品,研究了温度、时间、碱液量等因素,实验确立了最佳滴加温度、滴加时间、碱液用量,实验结果表明在最佳条件下得到的3,4-二乙氧基硝基苯(以下称精品)含量达到98%以上,收率97%以上。

3,4-diethoxynitrobenzene is an intermediate for the production of the fungicide ethamecarb. The industrial preparation method is to add o-phenylene diethyl ether and solvent to the reaction kettle, open stirring to control a certain temperature dripping with 65% nitric acid, and the crude product is obtained by cooling and filtering at the end of the reaction. The crude product has low content and contains acid and organic impurities (oxidation product). In this paper, the crude product was washed with 10% sodium carbonate aqueous solution, and the factors such as temperature, time and alkali content were studied. The optimum dripping temperature, dripping time and alkali dosage were determined. The experimental results show that under the optimum conditions, the content of 3,4-diethoxynitrobenzene (hereinafter referred to as fine) is more than 98%, and the yield is more than 97%.