Ni/ZrO2催化乙酰丙酸加氢制备γ-戊内酯

摘要

Five kinds of nickel supported zirconia (Ni/ZrO2) catalysts were prepared and characterized by N2 physisorption, X-Ray diffraction and transmission electron microscope(TEM) analysis. The effects of nickel loading and different reaction conditons on the catalytic activity were studied. The results showed that the conversion of levulinic acid increased with the increase of nickel content. It was found that the highest conversion could be achieved over 50 % Ni/ZrO2 and the highest turnover frequency(TOF) was obtained over 30% Ni/ZrO2. The reaction was accelerated with the increase of reaction temperature and much favored in dioxane than in water. The highest conversion of levulinic acid (99.1%) and yield of gamma-valerolactone (91.6%) were achieved after 9 hours under the conditions of 200℃ and hydrogen pressure of 5 MPa in dioxane.%以Ni/ZrO2为催化剂催化乙酰丙酸加氢制备γ-戊内酯,制备了5种不同Ni含量的Ni/ZrO2催化剂,采用氮气物理吸附、X射线衍射和透射电镜等对催化剂进行表征,并考察了催化剂的Ni含量、反应温度、反应时间、氢气压力和反应溶剂等条件对加氢催化活性的影响.结果表明:随着Ni含量的增加,乙酰丙酸的转化率也相应增加,Ni的质量分数为50%的Ni/ZrO2催化剂的乙酰丙酸转化率最高,Ni的质量分数为30%的Ni/ZrO2催化剂中单位Ni的比活性(TOF)最高;提高反应温度可加快反应速率;溶剂二氧六环比水更能促进反应的进行;而Ni含量及不同的反应条件对反应的选择性均没有显著的影响.在二氧六环中,温度200℃,氢压5 MPa下,反应9 h得到最高的乙酰丙酸转化率及γ-戊内酯收率,分别为99.1%和91.6%.