提高工艺安全性的FOX-7合成方法?

为了提高合成工艺的安全性,提出了一锅法制备1,1-二氨基-2,2-二硝基乙烯(FOX-7)的方法。控制反应体系温度在15℃左右,采用蠕动泵将浓硫酸连续地加入到2-甲基-4,6-二羟基嘧啶与二氯甲烷的悬浮液中,固体原料溶解后,再将发烟硝酸滴加到反应物料中,进行硝化反应;然后连续滴加水到反应器中,进行水解开环反应;再经过固液分离、洗涤和干燥,得到FOX-7。探讨了硝化剂的加料方式对收率和工艺安全性的影响。结果表明:惰性溶剂的引入,分散了反应物,硝化反应释放的热量可以及时扩散,物料温度控制更平稳,消除了物料团聚现象,而且与硝硫混酸加料相比,采用浓硫酸与发烟硝酸分步加料的方式,升温速率可降低51.0%,FOX-7的收率由63.0%提高到了82.6%,工艺的安全性显著提升。

A Synthesis Method to Improve Process Safety of FOX-7

The aim of this paper is to explore one-pot method for synthesis of 1, 1-diamino-2, 2-nitroethylene (FOX-7) to improve process safety. At 15 ℃, concentrated sulfuric acid was continuously added into the mixture of 2-methyl-4, 6-dihydroxypyrimidine and dichloromethane solvent by peristaltic pump to dissolve the solid material. And then fuming nitric acid was continuously added into the solution to complete the nitration reaction. Finally, water was added into the reaction system to complete the hydrolysis reaction without isolating the intermediate compound. After that, FOX-7 product was obtained through filtering, washing and drying. In addition, influences of nitration agent feed methods on product yield and safety properties were studied. Results show the feature of a better heat release from reaction system, a more consistent reaction temperature and the disappearance of material agglomeration due to the addition of inert solvent into dispersed reactants. Compared to adding mixed acid, the feeding method of using concentrated sulfuric acid to dissolve the raw mate-rial before adding nitric acid can reduce nitrification heating rate by 51. 0%, increase the yield of FOX-7 from 63. 0% to 82. 6%, and improve the process safety.