Ni/ZrO2-SiO2催化剂催化乙酰丙酸加氢合成γ-戊内酯

分别以ZrO₂、SiO₂及ZrO₂-SiO₂复合氧化物为载体，采用等体积浸渍法制备了Ni含量为10%（质量分数）的催化剂，考察了其催化乙酰丙酸液相加氢性能。采用N₂-物理吸附、NH₃-TPD、H₂-TPR、XRD、TEM等表征手段对催化剂进行了表征。研究结果表明，在所制备的催化剂上，乙酰丙酸先经C=O加氢生成4-羟基戊酸，后者快速脱水酯化为γ-戊内酯。Ni/ZrO₂-SiO₂催化剂较Ni/ZrO₂与Ni/SiO₂催化剂具有高的金属分散度和丰富的表面酸性中心，表现出高的C=O加氢活性以及优异的乙酰丙酸加氢合成γ-戊内酯性能。在反应温度为200℃，氢气压力4 MPa的反应条件下，乙酰丙酸的转化率达到100%，γ-戊内酯的选择性大于99.9%。

γ-Valerolactone synthesis from levulinic acid hydrogenation over Ni/ZrO2-SiO2 catalyst

ZrO₂、SiO₂ and ZrO₂-SiO₂ oxide composite supported Ni catalysts with Ni content of 10%(mass) were prepared by incipient impregnation method and characterized by N₂ physical adsorption, NH₃-TPD, H₂-TPR, XRD, TEM. The catalysts were evaluated for liquid phase hydrogenation of levulinic acid. The results showed that levulinic acid was first hydrogenated to 4-hydroxy valeric acid via C=O hydrogenation and γ-valerolactone was then produced by immediate esterification of 4-hydroxy valeric acid. Compared to Ni/ZrO₂ and Ni/SiO₂ catalysts, Ni/ZrO₂-SiO₂ catalyst exhibited highest dispersion of metallic Ni and most surface acid sites. As a result, the Ni/ZrO₂-SiO₂ catalyst demonstrated highest activity for C=O hydrogenation and superior performance for synthesis of γ-valerolactone via levulinic acid hydrogenation. 100% levulinic acid conversion and over 99.9% γ-valerolactone selectivity were achieved under reaction temperature of 200℃ and hydrogen pressure of 4 MPa.