两步法合成2-氨基-5-硝基苯酚

以邻氨基苯酚和尿素为原料,将传统环合-硝化-水解三步法工艺改为环合硝化-水解两步法合成了2-氨基-5-硝基苯酚(ANP);研究了影响环合硝化反应和水解反应的因素;优化了反应条件。环合硝化反应的最优条件为:n(邻氨基苯酚)∶n(尿素)=1.00∶1.20、环合时间6h、硝酸用量40.2g、硫酸用量20g、硝化时间3h、硝化温度70℃,在此条件下中间产物6-硝基苯并噁唑酮的收率为90.2%;水解反应的最优条件为:体积分数95%的乙醇为溶剂、n(6-硝基苯并噁唑酮)∶n(氢氧化钠)=1.0∶3.3、水解温度80℃、水解时间15h,在此条件下ANP收率为81.2%。两步反应ANP的总收率为73.2%。对产品进行了元素分析和红外光谱表征,确认终产物为ANP。该方法成本低,ANP总收率高,溶剂可回收,三废量少。

Synthesis of 2-Amino-5-Nitrophenol by Two Step Process

2-Amino-5-nitrophenol(ANP) was synthesized from o-aminophenol and urea by cyclocondensation-nitration as first step,which was an integration of traditional cyclocondensation and nitration,and following hydrolysis.Factors influencing the cyclocondensation-nitration and hydrolysis were studied.Under optimal cyclocondensation-nitration conditions: n(o-aminophenol)∶n(urea) 1.00 ∶1.20,cyclocondensation time 6 h,nitric acid 40.2 g,sulphuric acid 20 g,nitration time 3 h and nitration temperature 70 ℃,yield of intermediate 6-nitrobenzoxazolone is 90.2%.Under the optimal conditions of following hydrolysis: n(6-nitrobenzoxazolone) ∶n(sodium hydroxide) 1.0 ∶3.3,ethanol(95%) as solvent,hydrolysis temperature 80 ℃ and time 15 h,yield of ANP is 81.2%.Overall yield of ANP from above two step reactions is 73.2%.The product was identified by means of element analysis and IR.The new process leads to lower cost and higher product yield than the traditional.The solvent can be recovered.