Supercritical carbon dioxide extraction of Estonian oil shale

Results on the application of supercritical carbon dioxide extraction (SFE) at different temperatures are presented, and comparison with classical Sox hlet chloroform extracts is made. Pure carbon dioxide extracted preferably n-alkanes, whereas modifying of the fluid with methanol intensified the ext raction of more polar compounds and increased as a result total yield of ex tract. Increasing of SFE temperature had the same influence on the yield of extract, however, already at 200 degrees C partial heterolytic cracking of the kerogen of kukersite started. The similarity of composition and relati ve distribution of n-alkanes, n-alkanones-2, n-alkylbenzenes and n-alkylcyc lohexanes in both SFE and Soxhlet extracts of kukersite was observed.