Bi_2O_3/C催化水合肼还原间硝基三氟甲苯制备间三氟甲基苯胺

Reduction of 1-Nitro-3-( trifluoromethyl)-benzene Compounds with Hydrazine Hydrate to 3-Trifluoromethylaniline Catalyzed by Bi_2O_3/C

以硝酸铋和氢氧化钠为原料、活性炭作载体,采用水热法合成了Bi2O3/C催化剂,并利用X-射线衍射(XRD)对其结构进行表征。XRD图谱分析表明,Bi2O3在催化剂中以δ形态存在。同时,利用该催化剂还原间硝基三氟甲苯制备间三氟甲基苯胺,考察不同负载量的催化剂、催化剂用量、投料比和温度等因素对还原间硝基三氟甲苯制备间三氟甲基苯胺反应产率的影响。实验结果表明,0.002 mol/4 g Bi2O3/C具有良好的催化活性。最佳反应条件为:25 m L乙醇回流,0.002 mol/4 g Bi2O3/C催化剂用量为0.3 g,80%的水合肼和间硝基三氟甲苯的物质的量比为2∶1。催化剂重复使用9次仍保持较高的催化活性,收率可达98%。XPS图谱表明,使用前后催化剂中的铋未流失,且铋的价态不发生改变。

Bi2O3/ C catalysts were prepared via hydrothermal method with Bi（ NO3）3and Na OH as raw materials and activated carbon as carrier. X-Ray diffraction（ XRD） was used to measure the structure of prepared Bi2O3/ C catalysts and indicated that bismuth oxide existed as δ-form in Bi2O3/ C catalyst. In addition,Bi2O3/ C was used to deoxidize 1-nitro-3-（ trifluoromethyl）-benzene compounds to 3-trifluoromethylaniline,and the effects of various reaction parameters such as the category of catalysts,the amount of catalysts,material ratio and reaction temperature were investigated in detail. The results indicated that 0. 002 mol /4 g Bi2O3/ C showed well catalytic activity. The optimal reaction conditions were confirmed as follows： 25 m L ethanol was used as solvent under reflux,the amount of 0. 002 mol /4 g Bi2O3/ C catalyst was 0. 3 g,and the molar ratio of hydrazine hydrate and 1-nitro-3-（ trifluoromethyl） benzene was 2∶ 1. The catalytic remained high catalytic activity after 9 runs,and had a yield of 98%. The XPS spectra showed that both the valence and amount of the bismuth are the same after Bi2O3/ C was used.