The kinetic behaviour of 22 brown coals was investigated in direct hydroliquefaction. Yield data of the pseudocomponent formation were obtained from 0.11 microautoclave experiments carried out at 450 °C and reaction times from 0 to 60 min in the presence of tetralin as vehicle and iron sulphate as catalyst under a hydrogen blanket. The computer simulation of the hydrogenation kinetics was used to calculate rate constants, which were used as time independent characteristics of hydroliquefaction reactivity. Data on hydrogen distribution of the oils formed during hydrogenation were obtained by 1H n.m.r. spectroscopy of oils from ‘dry’ hydrogenation. Structural parameters calculated from n.m.r. measurements were used as independent variables for the development of statistical models. Using a stepwise variable selection procedure for the development of multiple regression models of the rate constants, the influences of sulphur and the aromaticity of coal oils were found. These and other minor influencing factors of reactivity such as ash content were discussed in terms of their effect on mechanism.