Methylation of Volatile Fatty Acids with Ordered Mesoporous Carbon and Carbon Nanotube for Renewable Energy Application

This study introduces a new way to convert volatile fatty acids (VFAs) into fatty acid methyl esters (FAMEs) at ambient initial pressure with ordered mesoporous carbons (OMCs) and multiwalled carbon nanotube (MCNT). Activity for the methylation is contingent on the structure and geometry of the carbon materials. CMK-5 having an interconnected rod structure with hollow rod-type carbon framework exhibited the highest activity for the methylation of VFAs among the OMCs tested in this study. Reaction temperature (360 °C) and a VFA/methanol volumetric ratio (0.5) for the methylation with the CMK-5 were optimized. At the optimized conditions, the FAME yields were reached up to ∼98%. A recycling study reveals that the CMK-5 was stable after six cycles with no sign of deactivation. The CMK-5 and MCNT showed a similar FAME yield profile for the methylation of VFAs due to their similar geometry. This study suggests a new use of carbon materials for producing short chain fatty alcohols considered as an alternative g...