Thermal cracking of regular and irregular Isoprenanes C<sub>20</sub>-C<sub>40</sub>
Thermal cracking of regular and irregular isoprenanes С20-С40 was carried out, followed by the research of the distribution patterns of regular, irregular and pseudoregular isoprenanes C10-C20. It was found that no rupture of terminal methyl, ethyl and isopropyl groups occurs as a result of thermal cracking of phytane, krotsetane, squalane and likopane. The simultaneous rupture of C-C bonds at tertiary carbon atoms in the molecule isoprenanes doesn’t occur either. It was shown that the value of the ratio of genetic pristane/phytane indicator, which is used in the petroleum geochemistry for correlations of oil-oil and oil-extracted organic matter systems should be treated with caution.