间三氟甲基硝基苯的超临界催化加氢

Study on Hydrogenation of m-Trifluoromethylnitrobenzene in Supercritical Carbon Dioxide

研究了用超临界二氧化碳作为反应介质来提高间三氟甲基硝基苯的加氢反应速度和选择性。实验考察了二氧化碳压力、加氢反应温度、氢气浓度、反应空速等因素对超临界加氢反应的影响。结果表明,在二氧化碳压力为9.5MPa, 反应温度为45℃,氢气浓度为0.6molL-1,反应空速为1.0min-1的条件下,间三氟甲基硝基苯的转化率为99.5%,选择性为100%。同时,在45℃时超临界催化加氢反应速度是液相加氢时的29倍。

In order to improve the reaction environment, the supercritical carbon dioxide was used as a solvent to enhance the hydrogenation rate and selectivity of m-trifluoromethylnitrobenzene reduction. Under supercritical conditions, the limitations of hydrogen transport are eliminated and the products of m-trifluoromethylaniline are obtained directly without separation. Very high hydrogenation rate of m-trifluoromethylnitrobenzene to m-trifluoromethylaniline occurs when the reaction is conducted in homogeneous supercritical phase, using carbon dioxide as the solvent. The hydrogenation rate of trifluoromethy Initrobenzene is 29 times higher than that in liquid phase hydrogenation. The experiments showed that the hydrogen concentration is an important factors for achieving high hydrogenation rate and selectivity. At the condition of carbon dioxide pressure 9.5 MPa, temperature 45°C, hydrogen concentration 0.6 mol &middotL-1 and space velocity 1.0 min-1, high conversion of 99.5% was obtained and the selectivity of m-trifluoromethylaniline reached to 100%.