常压下由对甲酚催化氢化制备4-甲基环己酮

Preparation of 4-Methylcyclohexanone by Catalytic Hydrogenation of p-Cresol at Normal Pressure

4-甲基环己酮作为一种优良的有机溶剂及有机合成中间体,在微电子工业及医药、香料、精细化工合成中有很重要的用途。文献报道的各种制备方法中,以对甲酚为原料经催化氢化制备4-甲基环己酮有实际意义。但催化氢化大多在加压情况下进行,所用催化剂多为钯,也有用钉、铑或莱尼镍作催化剂的,但加氢产物多为甲基环己醇,且酮的收率很低。本文采用铑催化剂(以氧化铝作载体),实现了对甲酚的常压催化氢化,制得4-甲基环己酮,并对催化条件作了初步摸索和探讨。

4-Methylcyclohexanone was prepared by the catalytic hydrogenation of p-cresol at normal pressure over Rh on 3. 17 mm alumina pellets as the catalyst. The conditions for the catalytic hydrogenation were also studied. The preheated temperature of p-cresol was chosen as 160X^. The rate of flow of hydrogen was selected to be 144 L/h. The mixture ratio of the reacting gas was hydrogen i p-cresol=15 : 1 (molar ratio). When the catalytic temperature was 60,80,100,120,140,160,180, 200, 220℃ , the conversion rate of p-cresol was found in 0. 1, 33. 3, 33. S, 18, 3,12. 7,1. 0, 0. 2, 0. 2,0. 5% , respectively.