Cu-Mo/C催化油酸甲酯选择性加氢脱氧制备生物柴油

Preparation of Biodiesel by Selective Hydrodeoxygenation Methyl Oleate over Cu-Mo/C Catalyst

使用四水合钼酸铵和三水合硝酸铜制备了Cu-Mo/C,并将其用作油酸甲酯选择性加氢脱氧反应的催化剂。利用X射线衍射(XRD)、X射线光电子能谱(XPS)和电子顺磁共振波谱(EPR)对催化剂进行表征,并探讨了Cu-Mo/C催化油酸甲酯制备生物柴油的较佳工艺和Cu-Mo/C的催化性能。研究结果显示:Cu的加入促进了Mo/C催化剂的形成,催化剂中的Mo_(2) C组分和MoO_(2)组分共同作用,MoO_(2)组分中的氧空位可以优先吸附底物中的C=O键,随后Mo_(2) C组分对其进行加氢脱氧,避免了C=C键发生加氢反应,实现了高催化活性和不饱和烃选择性加氢脱氧的优异性能。在反应温度280℃,氢气压力2.5 MPa,反应时间3 h的条件下油酸甲酯转化率达到98.8%,不饱和烃选择性为40.2%。Cu-Mo_(10)/C催化活性与贵金属Pd和商业催化剂Mo/C相当,但不饱和烃选择性更高,且具有良好的稳定性。

The Cu-Mo/C catalyst was prepared with ammonium molybdate tetrahydrate and copper nitrate trihydrate,and used for the selective hydrodeoxygenation reaction of methyl oleate.The catalysts were characterized by X-ray diffraction,X-ray diffraction photoelectron spectroscopy and electron paramagnetic resonance spectroscopy.The optimal process for the preparation of biodiesel from methyl oleate catalyzed by Cu-Mo/C and the catalytic performance of Cu-Mo/C were investigated.The results of the study showed that the addition of Cu promoted the formation of Mo/C catalyst and the Mo_(2) C and MoO_(2) component in the catalyst worked together.The oxygen vacancies on the MoO_(2) component could preferentially adsorb the C=O bond in the substrate and then Mo_(2) C component hydrodeoxygenated it,avoiding the hydrogenation of C=C bond.The excellent performance of catalyst and the selectivity of unsaturated hydrocarbons were achieved.The conversion rate of methyl oleate reached 98.8%,and the selectivity of unsaturated hydrocarbons was 40.2%at reaction temperature of 280℃,hydrogen pressure of 2.5 MPa and reaction time of 3 h.The catalytic activity of Cu-Mo_(10)/C was comparable to the noble metal Pd and commercial Mo/C catalysts,while the unsaturated hydrocarbon selectivity was higher as well as the good stability.