Application of ESR for coal pyrolysis and quench solvent evaluation

Studies of the role played by free radicals in the improvement of product yields and quantity of the coal liquids produced by pyrolysis of coal are reported. ESR technique was used for the detection of phenalenyl-like radicals in the vapors from coal pyrolysis, and computer modelling coupled with the ESR spectral data indicated that the observed spectral from the vapor seemed to be a mixture of alkyl phenalenyl radicals. However, this finding did not rule out the production of shorter lived radicals which might have been produced but not attained enough concentration to be detected by the procedure being studied. An evaluation of quench solvents with emphasis on decay kinetics was carried out for cumene, mesitylene, tetralin, hydrophenanthrene (a mixture of products of hydrogenation of phenanthrene under hydrogen pressure at 1500 to 2800 psi and 370/sup 0/C with Shell No. 454 catalyst), and Indan; and pseudo first order rate constants are compared with the solvent indices. (BLM)