Thermodynamic data of known volatile organic compounds (VOCs) in Rosmarinus officinalis: Implications for forest fire modeling

Abstract

Various volatile organic compounds (VOCs) are known to form in forest fires. They may also be formed in oxidation and pyrolysis of biomass. Prior to the building of detailed chemical kinetic models for biomass combustion, thermodynamic data of species are needed. Structures for α-pinene, limonene, camphene, filifolone, β-pinene, myrcene, p-cymene, thuja-2,4-(10)-diene, verbenone, terpinolene, sabinene, α-terpinene, γ-terpinene and camphor were computed at the B3LYP/6-31G(d,p) level of theory. Thermochemical properties, ΔfH°(298), S(T) and Cp(T) of target molecules were calculated using density functional theory. Enthalpies of formation were determined at the B3LYP/6-31G(d,p) level using two semiempirical atomization methods. Because these methods failed to agree with known values for limonene and camphene, higher level composite methods [G4 and the correlation consistent composite approach (ccCA)] were considered.