Synthesis of biodiesel by carbon nanotubes doped Fe(Ⅱ)-Zn double metal cyanide catalysts

A series of carbon nanotubes (CNTs) doped Fe(Ⅱ)-Zn double metal cyanide (DMC) catalysts was prepared for biodiesel synthesis. The structure and performance of the catalysts were studied by using X-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscope. It was found that the catalyst with 5 wt% of the CNTs showed the optimum transesterification activity. A high yield (95.8 %) of fatty acid methyl esters (FAME) was obtained with methanol/oil molar ratio of 16:1, catalyst amount of 2 wt%, reaction temperature at 160℃ and reaction time 7 h. The analysis results show that carbon nanotubes (CNTs) doped Fe(Ⅱ)-Zn DMC catalysts did not change the composition of Fe(II)-Zn catalysts, while it improves particle dispersion, decreases particle size and increases more pore. This is the main reason that carbon nanotubes doped DMC catalysts have good transesterification activity.