ORGANIC-COMPOUNDS FROM INSOLUBLE ORGANIC-MATTER ISOLATED FROM THE MURCHISON CARBONACEOUS CHONDRITE BY HEATING EXPERIMENTS

Insoluble organic matter isolated by an HF/HCl treatment of the Murchi son carbonaceous chondrite was heated from room temperature to 800 deg rees C at a rate of 10 degrees C min(-1) under a helium atmosphere. Ov er 130 organic compounds were identified in its pyrolyzates, which mai nly comprised the following two groups: (1) benzene and naphthalene, a nd their alkyl derivatives; and (2) sulfur-containing heterocycles and their alkyl derivatives. The relative amounts of compounds released w ith increasing temperature: during the heating process were monitored by a mass spectrometer. Those hydrocarbons were observed mainly over a temperature range of 300-600 degrees C. These results are generally s imilar to those of Yamato-791198, an Antarctic carbonaceous chondrite which we had previously analyzed. The results indicate that aliphatic and aromatic hydrocarbons, as well as S-containing heterocycles, are t he major constituents of the insoluble organic matter of Murchison. Fu rthermore, the results suggest that the thermal history of Murchison o n its parent body was similar to that of Yamato-791198.