The influence of pressure (within a range of 5-100 MPa) on the rate of hydrogen transfer from tetralin to various coal macerals has been studied. Ten maceral concentrates (five vitrinites, three inertinites, and two liptinites) were used. The reactions were conducted at a temperature of 310 or 320 degrees C, depending on sample reactivity. The progress of reaction was followed by measuring tetralin dehydrogenation with gas chromatography. Vitrinite concentrates with high oxygen content are the most reactive, and the rate of their reaction with tetralin is accelerated by pressure. Pressure effects suggest a bimolecular transition state for most vitrinite/tetralin reactions. The reaction rate of inertinite concentrates is unchanged or even slowed by the change in pressure. These results suggest the increased contribution of the radical capping mechanism or the reaction path, in which tetralin reacts with low-energy coal radicals. As the pressure increases, the reaction rate of one liptinite sample is accelerated while the reaction of the other liptinite is retarded.