2,4,6-三硝基-1,3,5-三羟基苯的新制备方法

A New Preparation Method of 2,4,6-Trinitro-1,3,5-trihydroxybenzene

为降低2,4,6-三硝基-1,3,5-三羟基苯(TNPG)在生产过程中对环境造成的危害并探究其高效且低污染的规模化生产工艺,本文以3,5-二甲氧基氟苯为原料,通过硝酸钾-浓硫酸组成的硝化体系进行硝化。在冰水淬灭硝化反应时氟原子被水解,得到中间体3,5-二甲氧基-2,4,6-三硝基苯酚(2),用冰乙酸溶解中间体2,再用氢溴酸脱甲基得到目标化合物TNPG,总收率96.13%。对该反应进行公斤级规模放大,发现重现性较好。采用核磁共振(NMR)、X-射线单晶衍射分析(XRD)和元素分析(EA)等方法对TNPG进行结构表征,利用差示扫描量热(DSC)和热重(TG)方法研究TNPG的热分解过程,结果表明:TNPG在157.11℃出现吸热峰,在171.60℃和191.63℃处出现放热峰。该合成方法简洁且收率较高,在温度为-173.15℃时,6TNPG·4H_(2)O单晶密度为1.9389 g/cm^(3),属trigonal晶系,P-3c1空间群。

In order to reduce the harm to the environment caused by 2,4,6-trinitro-1,3,5-trihydroxybenzene(TNPG)in the production process and explore its large-scale production process with high efficiency and low pollution,3,5-dimethoxyfluorobenzene as the starting material is nitrated in a nitration system composed of potassium nitrate and concentrated sulfuric acid.While quenching the reaction with ice water,the fluorine atom is hydrolyzed to obtain the intermediate 3,5-dimethoxy-2,4,6-trinitrophenol(2).After demethylation of intermediate 2 with hydrobromic acid,TNPG is obtained with an overall yield of 96.13%.At the same time,the reaction was scaled up in kilogram scale with good reproducibility.The structure of TNPG is characterized by nuclear magnetic resonance(NMR),X-ray single crystal diffraction(XRD)and elemental analysis(EA).The thermal decomposition process of TNPG is studied by differential scanning calorimetry(DSC)and thermogravimetry(TG).TNPG has an endothermic peak at 157.11℃,and two exothermic peaks at 171.60℃and 191.63℃.The results show that the synthesis method is very simple and the yield is high.If the mixture of acetic acid and hydrobromic acid is recovered,the concentration of TNPG in the waste liquid will be reduced to zero.The crystal of 6TNPG·4H_(2)O is directly obtained by this method.Its single crystal density is 1.9389 g·cm^(-3)at-173.15℃,which belongs to trigonal crystal system and P-3c1 space group.