Exploratory study of coal conversion chemistry. Quarterly report No. 10, August 19-November 18, 1983

Work has continued to focus this quarter on Subtask A.3, Derivation of an Improved Correlation Between Coal-Conversion Effectiveness and Donor-Solvent Structure. We are taking two new approaches to test the hypothesis that the critical class of reactions, which distinguishes between good donor and poor donor solvents, is bimolecular transfer of hydrogen atoms from solvent radicals to the ipso positions of substituted aromatics Ar-X, resulting in solvent-mediated hydrogenolysis. In the first approach, experiments in which real coal liquefaction mixtures were doped with specific model compounds showed that hydrogen-transfer reactions promoted by the coal do engender bond scission in the dinaphthylmethane to an extent that the half-life for cleavage at 400/sup 0/C in tetralin is decreased from 200 hours to about 4 hours. This result greatly strengthens our suggestion that the cleavage of phenyl-alkyl bonds, formerly considered to be very refractory under liquefaction conditions, may play an important role in coal liquefaction. In the second approach to testing our liquefaction mechanism hypothesis, we have constructed a simplified numerical model for liquefaction of some coal-like structures, incorporating some of the rate constants for bond cleavage measured in this work to determine whether the calculated relative bond cleavage rate with various hydroaromatic contents successfully mimics the relative model compound and coal conversion rates measured in the laboratory. Our efforts in Task B were concentrated on Subtask B.1 Development and Evaluation of CO/H/sub 2/O Catalyst Systems. The study of conversion behavior of an Illinois No. 6 coal was extended to different reaction times and lower pH's. The results reveal that the primary reaction parameter that controls coal conversion at 400/sup 0/C is the amount of CO that is allowed to enter the reaction pathway. 24 references, 8 tables