Effect of electrolytic systems on electrochemical hydrogenation of mesophase coal tar pitch

A mid-temperature coal tar pitch (CP) was extracted by pyridine and heat-treated to obtain a mesophase coal tar pitch (MCP). The microstructures of refined coal tar pitch (RCP) and MCP were observed, and the properties of MCP were improved by electrochemical hydrogenation. Electrolytic systems, such as electrolytic cells, electrolytic solvents, supporting electrolytes, and cathode materials, used for electrochemical hydrogenation of MCP are discussed. The results showed that the hydrogen content (H%) and ratio of hydrogen to carbon (H/C) of hydrogenated MCP (HMCP) were increased, and the softening point (SP) was decreased in comparison with untreated MCP. IR and 1H-NMR spectra established that –CH3 and –CH2 had appeared in HMCP, and the ratio of aromatic hydrogen to aliphatic hydrogen of HMCP was decreased.