Coal; Carbon; Alkanols; Immersion calorimetry; Micropores accessibility;

Two natural coals and a sample of activated carbon were studied with respect to micropores accessibility for C1-C4 alkanols using immersion calorimetry. From the immersion enthalpies, micropores volumes were calculated according to the Stoeckli-Kraehenbuehl (SK) equation, and obtained values were compared with the surface characteristics of gas adsorption measurements. Validity of the SK equation was found to be problematic for natural coals giving micropores volumes up to 3 times exceeding those of the CO2 adsorption measurements. The possible reason for such discrepancy is discussed. A drop in immersion heats with branched butanols was generally observed, enabling at least semi-quantitative evaluation of the abundance of micropores with diameters below ca. 0.7 nm that are inaccessible for tert-butanol.