Thermolysis of sulfate turpentine was studied in the pressure range of 40-280 atm. The conversion kinetics of main turpentine components (alpha-pinene, 3-carene) and their isomerization products (limonene, alloocimenes, pyronenes) was investigated and compared with the conversion kinetics of these compounds in supercritical ethanol. Thermodynamic parameters Delta(H) over bar#, Delta(S) over bar# and Delta(G) over bar# of the reversible reaction "alpha-pinene-[TS]" were estimated, the observed discrepancies being interpreted in the context of transition state theory. The thermolysis rate of alpha-pinene as a turpentine component was compared to that in a supercritical diluted solution of ethanol versus pressure. The rate of alpha-pinene conversion was shown to depend on the density of working medium. (C) 2008 Elsevier B.V. All rights reserved.