铬形态及使用条件对糠醛催化加氢反应产物分布的影响

Effect of chromium state and reaction conditions on the product distribution of furfural catalytic hydrogenation

采用共沉淀法制备系列Cu-Cr糠醛加氢催化剂,考察不同铬形态对催化剂反应性能的影响。采用管式连续流动固定床积分反应器,研究糠醛在Cu-Cr催化剂上的气-液相加氢反应规律。结果表明,制备催化剂时的铬原料不同,将极大地影响催化剂的加氢活性和产物选择性,以硝酸铬形式加入制备的催化剂对糠醇的生成较为有利,而以醋酸铬形式加入制备的催化剂对甲基呋喃的形成有利;在(70～110)℃,随着温度升高,糠醛转化率和糠醇选择性增加,2-甲基呋喃选择性降低;糠醛流速为(0.01～0.06)mL.min-1时,随着流速的增加,糠醛转化率下降,0.03 mL.min-1时糠醇选择性出现极大值,而副产物2-甲基呋喃和呋喃类则在此处出现极小值。副产物戊二醇和四氢康醇的选择性则随着糠醛流速的增大上升。

A series of Cu-Cr furfural hydrogenation catalysts was prepared by the coprecipitation method, and the effects of Cr state on the catalytic activity of the catalysts were studied. The catalytic activity of the catalysts for furfural gas-liquid phase hydrogenation was investigated using a continuous flow fixed-bed tubular integral reactor. The results showed that the catalyst prepared with chromium nitrate was beneficial to the formation of furfuryl alcohol, whlie the catalyst prepared with chromic acetate was favorable to the formation of methylfuran. At （ 70 - 110 ） ~C, furfural conversion and the selectivity to furfuryl alcohol enhanced, and the selectivity to 2-methylfuran decreased with the increase of the temperature. In the range of flow rate （0.01 -0.06） mL ·min^-1 ,furfural conversion decreased and the selectivity to 1,5-pentanediol enhanced with the increase of flow rate ; when the flow rate was 0.03 mL ·min^-1, the selectivity to furfuryl alcohol reached the maximum and the selectivity to the by-products 2-methylfuran and furan reached the minimum.