Isothermal pyrolysis of raw and demineralized Sirnak asphaltite (SASP) was investigated to determine product yield and distribution of volatile products at different temperatures. First, asphaltite sample treated with HCl, HNO(3) and HF to remove carbonates, pyrite and silicates from organic structure. Then, raw and these treated asphaltite samples were pyrolyzed in isothermal pyrolysis reactor at 450, 500, 550, 600 and 650 degrees C. Pyrolysis products were analyzed by capillary gas chromatography. Volatile hydrocarbon recovery (VHR) and total hydrocarbon recovery (THR) were calculated. VHR and THR were increased with increasing temperature. In contrast, solid residue decreased. Removal of carbonates and pyrite decreased the volatile product yield. However, for HF treated samples gas product evolution increased. Carbon balance established around the reactor, carbon in solid residue was determined and asphaltene and pre-asphaltene fractions were calculated. In addition, n-paraffins and 1-olefins were grouped according to the carbon number. (C) 2011 Elsevier Ltd. All rights reserved.