Thermal decomposition of methylxanthines

Abstract

The thermal decomposition of theophylline, theobromine, caffeine, diprophylline and aminophylline were evaluated by calorimetrical, thermoanalytical and computational methods. Calorimetrical studies have been performed with aid of a heat flux Mettler Toledo DSC system. 10 mg samples were encapsulated in a 40 μL flat-bottomed aluminium pans. Measurements in the temperature range form 20 to 400°C were carried out at a heating rate of 10 and 20°C min−1 under an air stream. It has been established that the values of melting points, heat of transitions and enthalpy for methylxanthines under study varied with the increasing of heating rate.