Pyrolysis of Manvers coal in an atmosphere of deuterium

Abstract

Manvers coal was pyrolysed to 500 °C in an atmosphere of deuterium using an autoclave described previously 1. The final pressure was 2.64 MPa. Deuterium-hydrogen ratios were found to be 0.4 in the resulting semicokes (by diffuse reflectance infrared spectrometry), 1–2 in selected tar compounds (by g.c.-m.s.), 1.1 in the liquor (from refractive indices) and 0.16 in the hydrocarbon gases (by high-resolution m.s.). These ratios were unaffected by the addition to the coal of 5% of either tetralin or pyrite. The relative proportions of deuterated methanes, dibenzofurans and C 3 phenols were consistent with the random scrambling of deuterium and hydrogen atoms. The distributions of other deuterated hydrocarbon gases and tar compounds showed deviations from the predictions of random scrambling. The ineffectiveness of deuterium in capping radicals is emphasised and the results are explained in terms of the inhibition of the diffusion of deuterium and hydrogen by the development of plasticity during pyrolysis.