COAL-GASIFICATION STUDIES .3. REDUCTION IN THE PRESENCE OF SOME METAL IODIDES AND IRON HALIDES

Coal has been reduced at 600°C with H2 (1700-3000 p.s.i.) in the presence of (1) iodides of the metals Fe, Cr, Mo, Ni, Sn and Zn, and (2) the halides of iron, FeX3 (X = F, Cl, Br and I), as potential catalysts, CH4, C2H4 and C3H8 were the only hydrocarbon reaction products. With the possible exception of ZnI2, for which the results are somewhat equivocal, there is no reason to believe the iodides of these metals have significant catalytic effect on coal reduction. Rather, they act solely as a source of iodine which is the true catalytic agent. FeF3 shows no catalytic activity in the reduction process, whereas the other iron halides apparently do, the order of effectiveness being FeI3 > FeBr3 > FeCl3. Thermodynamic data are used to show that in part, at least, the effectiveness of these compounds as catalysts is probably associated with the equilibrium HX ⇌ H + X (X = I, Br, Cl, and F) which produces a small finite steady state concentration of reactive H atoms in the system. The latter, in the HF system, is too low to have any significant effect on the reduction. The results of experiments on the reduction of some pure saturated aliphatic and aromatic compounds with H2O + Fe + I2 are described. © 1979.