Eight Canadian coal samples were subjected to supercritical toluene extraction at 653°K and 20 MPa. The relationship between the chemical composition and the reactivity of coal, in terms of conversion to tars and gases were studied using a multivariate analysis method in order to establish the relative importance of the chemical constituents. An empirical model which predicts the conversion of coal with good accuracy was developed. The variation of coal conversion with chemical composition was investigated using a three dimensional response surface methodology. The results show that the hydrogen and sulfur content of coal have the most significant influence on conversion. Increasing amounts of these two chemical constituents in coal leads to an almost linear increase in conversion, whereas higher contents of oxygen, fixed carbon and ash were found to be deleterious to coal conversion.