The thermal decomposition of several sulfonamides and potassium salts of sulfonamides was investigated. The analyses were
performed using a derivatograph in an air atmosphere, sample sizes were from 50 to 200 mg and heating rate from 2.5 to 20
K min-1. It has been established, that the thermal destruction of studied compounds occurs via three stages with formation of potassium
carbonate as a final product of the complete combustion of potassium salts of sulfonamides. The temperature ranges, in which
the analyzed compounds undergo thermal transformations were established. For evaluation of the results the principal component
analysis (PCA) was applied. By this method the influence of the specific functional groups on the thermal decomposition of
sulfonamides and potassium salts of sulfonamides was determined. It has also been recognized, that better discrimination among
the analyzed compounds is obtained for the data set of the DTA.