Ziwei Guo,Feng Zhou,Hao Wang,Xiaohao Liu,Guangyue Xu,Ying Zhang,Yao Fu
A novel and green catalytic system based on a Pd stabilized CuZnAl catalyst was designed for one-pot conversion of natural oil components to the corresponding alcohols or long-chain linear and branched alkanes with high selectivity and atom economy. When methyl decanoate was used as the model compound, a nearly full yield of n-decanol was obtained at 200 °C and 2 MPa H2 within 8 h. 100% decane was produced when acidic HZSM-5 was introduced under the same reaction conditions, and the selectivity of n-decane and i-decane could be tuned by temperature. Cu species were verified as the active sites for lipid conversion, while a small amount of Pd could stabilize the catalyst to avoid Cu leaching. The reaction pathway involved hydrogenation, where methyl decanoate can be equivalently converted to methanol and decanol or decane, and no extra CO2 or CO from decarboxylation or decarbonylation was detected. This system increases the sustainability and economy of natural oil conversion to valuable liquid fuel and chemicals.
Wenda Jia,Guangyue Xu,Xiaohao Liu,Feng Zhou,Huixia Ma,Ying Zhang,Yao Fu
Inedible natural oils are desired resources for renewable fuel and chemical production. Herein, a nonprecious metal cobalt catalytic system was developed for selectively hydrogenating fatty acids and natural oil into fatty alcohols or long-chain alkanes. The cobalt-based catalysts were prepared by a wet-impregnation method with a series of supports including HZSM-5, CeO2, ZrO2, SiO2, Al2O3, TiO2, and hydroxyapatite (HAP) for hydrogenating stearic acid. Among these catalysts, Co/HAP exhibited the highest activity and 97.1% yield of 1-octadecanol was obtained at 190 °C and 4 MPa H2 in water. Additionally, the Co/HAP was capable of directly hydrogenating the natural oil, Jatropha oil, to fatty alcohols without any preprocessing, and 83.1 wt % yield of alcohols could be achieved at 190 °C and 4 MPa H2 in water. Co/HAP could also catalyze the complete conversion of stearic acid and Jatropha oil to long-chain alkanes when dodecane was used as solvent. X-ray power diffraction, transmission electron microscopy, H2 temperature-programmed reduction, and NH3 temperature-programmed desorption were carried out, and the high catalytic activity of Co/HAP could be due to its desired acidity, cobalt particle dispersion, and stronger metal–support interaction. The Fourier transform infrared results indicated that the high efficiency of Co/HAP could also be due to the absorption of fatty acid on the surface of catalyst which thus promoted the hydrogenation process over Co species. The possible reaction pathway was also proposed according to the conversion process tracking of stearic acid.
The hydrolysis of natural oils (vegetable oils and fats) by lipase has significant applications in food and medicine. However, free lipases are usually sensitive to temperature, pH and chemical reagents in aqueous solutions, which hinders their widespread industrial application. Excitingly, immobilized lipases have been widely reported to overcome these problems. Herein, inspired by lipase interface activation, a hydrophobic Zr-MOF (UiO-66-NH 2 -OA) with oleic acid was synthesized for the first time in an emulsion consisting of oleic acid and water, and the Aspergillus oryzae lipase (AOL) was immobilized onto the UiO-66-NH 2 -OA through hydrophobic interaction and electrostatic interaction to obtain immobilized lipase (AOL/UiO-66-NH 2 -OA). 1 H NMR and FT-IR data indicated that oleic acid was conjugated with the 2-amino-1,4-benzene dicarboxylate (BDC-NH 2 ) by amidation reaction. As a result, the V max and K cat values of AOL/UiO-66-NH 2 -OA were 179.61 μM﹒min −1 and 8.27 s −1 , which were 8.56 and 12.92 times higher than those of the free enzyme, respectively, due to the interfacial activation. After treated at 70 °C for 120 min, the immobilized lipase maintained 52 % of its original activity, but free AOL only retained 15 %. Significantly, the yield of fatty acids by the immobilized lipase reached 98.3 % and still exceeded 82 % after seven times of recycling.