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Role of group V elements on the hydrogenation activity of Ni/TiO2 catalyst for the vapour phase conversion of levulinic acid to γ-valerolactone
Catalysis Today ( IF 5.3 ) Pub Date : 2018-07-09 , DOI: 10.1016/j.cattod.2018.07.019
Ganga Bhavani Peddakasu , Vijay Kumar Velisoju , Manasa Kandula , Naresh Gutta , Komandur VR Chary , Venugopal Akula

Influence of group V elements such as Ta, Nb and V on the product distribution in the vapour phase hydrogenation of levulinic acid (LA) over Ni/TiO2 catalyst was examined at ambient pressure. The Nb promoted Ni/TiO2 demonstrated a high selectivity towards γ-valerolactone (GVL) compared to other catalysts at 275 °C. The TPR results showed a lower H2 uptake over Ta and V modified Ni/TiO2 which was explained due to a strong interaction between these oxide species with nickel. Presence of a high ratio of ionic nickel (Ni2+) on Ta and V modified catalyst could be a possible reason for the formation of valeric acid (VA) through the ring opening of GVL. The high GVL selectivity over the Ni-Nb/TiO2 catalyst attributed to the presence of a high proportion of Lewis acid sites in conjunction with finely dispersed Ni species on the catalyst surface. This however, is accomplished by the pyridine adsorbed diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and CO-chemisorption results.



中文翻译:

V族元素对Ni / TiO 2催化剂催化乙酰丙酸气相转化为γ-戊内酯的加氢活性的作用

在环境压力下检查了Ni,TiO 2催化剂上的V族元素(如Ta,Nb和V)对乙酰丙酸(LA)气相加氢中产物分布的影响。与其他催化剂相比,在275°C下,Nb促进的Ni / TiO 2对γ-戊内酯(GVL)的选择性高。TPR结果显示,与Ta和V改性的Ni / TiO 2相比,H 2的吸收量更低,这可以解释为由于这些氧化物与镍之间的强相互作用。Ta和V改性催化剂上存在高比例的离子镍(Ni 2+)可能是通过GVL开环形成戊酸(VA)的可能原因。在Ni-Nb / TiO 2上的高GVL选择性催化剂归因于在催化剂表面上存在高比例的路易斯酸位点以及精细分散的镍物质。但是,这是通过吡啶吸附的漫反射红外傅里叶变换光谱(DRIFTS)和CO化学吸附结果来完成的。

更新日期:2018-07-09
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