HYDROGEN TRANSFER FROM DECALIN TO COAL MACERALS

In order to study the mechanism of the reaction of decalin with a bituminous coal and maceral groups separated from it, the yields of transferred hydrogen, apparent activation energies and H/D kinetic isotope effects (KIE) have been measured. The balance of hydrogen transfer shows that the coal/decalin reaction can be considered as a set of parallel maceral/decalin reactions. The apparent activation energy varies from 87 kJ/mol for hydrogen transfer from decalin to exinite to 136 kJ/mol for hydrogen transfer from decalin to inertinite. The kinetic isotope effects at 400-degrees-C vary from 1.5 +/- 0.2 for inertinite/decalin reaction to 2.5 +/- 0.3 for exinite/decalin reaction. The values of KIE are inconsistent with the view that the rate is determined by homolysis of the coal molecules. The results indicate the differences in reaction mechanisms, and pathways for hydrogen transfer from decalin to maceral groups have been suggested.