法呢基丙酮的超临界催化加氢研究

Hydrogenation of Farnesylacetone(FA) in Supercritical Carbon Dioxide

以超临界二氧化碳为介质,3%Pd/C为加氢催化剂,在流动的固定床反应器中对法呢基丙酮进行催化加氢研究.当二氧化碳压力超过临界压力后,加氢转化率急剧上升,表明超临界条件对法呢基丙酮的催化加氢反应具有巨大的促进作用.在温度为42℃、二氧化碳压力为10.5MPa、空速为1.2m·min-1、氢气浓度为1.0mol·L-1的条件下,转化率可达到99.5%,选择性达到98.8%.与液相加氢反应比较,其加氢反应速度提高646倍.法呢基丙酮超临界加氢反应的较佳反应温度区间为35～50℃,在此温度下可以达到较佳的转化率.超临界加氢反应可以提高加氢速率与选择性,具有很大的优越性.

The stirred batch hydrogenation in liquid phase is the traditional method used for the catalytic hydrogenation of farnesylacetone (FA), which has the defects of long reaction time, excessive catalyst used and high by-products. Using 3% Pd/C as catalyst, the hydrogenation of FA in supercritical CO2 was compared with that in liquid phase. During the hydrogenation of FA in supercritical CO2 with the conditions of CO2 pressure 10.5 MPa, reaction temperature 42°C, hydrogen concentration 1.0 mol &middot L-1 and space velocity 1.2 m &middot min-1, the conversion rate 99.5% and selectivity 98.8% can be achieved and for the traditional method of hydrogenation in liquid phase, the conversion rate is only 1.35%. The hydrogenation speed expressed in turnover frequency is 586 min-1 for hydrogenation in supercritical CO2 and is only 0.88 min-1 for traditional in liquid phase. So the hydrogenation rate in supercritical CO2 is 646 times higher than that in liquid phase. It shows that the hydrogenation at the supercritical condition can enhance the reaction rate and selectivity obviously, and the supercritical CO2 is a good environment-friendly solvent for catalytic hydrogenation.