Reductive Alkylation of Anthracite: Edge Functionalization

Reduction of anthracite by electron transfer from either lithium or sodium in liquid ammonia yields a salt that can be alkylated by 1-iodododecane to yield nanocoal that is partially soluble in common organic solvents. NMR indicates that the dodecyl groups are attached to the edges of the aromatic ring systems, with many of the dodecyl groups extending into void spaces. Thermal gravimetric analysis shows that sodium gives a slightly higher level of functionalization. Atomic force microscopy (AFM) images of soluble dodecylated anthracite reveal nanoparticles that vary from 3 to 12 nm high. Scanning electron microscopy (SEM) and bright field high-resolution transmission electron microscopy (HRTEM) of the raw anthracite reveal a layered structure with dislocations. Inorganic materials that occur in the raw anthracite were identified by energy dispersive X-ray spectroscopy (EDS). Simple alkenes were found to react with the coal salt to give oligomers of the alkene that are grafted onto the surface of the coal.