View article

To model the emission dynamics and changes in fractional composition of monoterpenoids from plant leaves, temperature dependencies of equilibrium coefficients must be known. Henry’s law constants (H_pc, Pam³mol⁻¹ and octanol/water partition coefficients (K_OW, molmol⁻¹) were determined for 10 important plant monoterpenes at physiological temperature ranges (25–50°C for H_pc and 20–50°C for K_OW). A standard EPICS procedure was established to determine H_pc and a shake flask method was used for the measurements of K_OW. The enthalpy of volatilization (ΔH_vol) varied from 18.0 to 44.3kJmol⁻¹ among the monoterpenes, corresponding to a range of temperature-dependent increase in H_pc between 1.3- and 1.8-fold per 10°C rise in temperature. The enthalpy of water–octanol phase change varied from −11.0 to −23.8kJmol⁻¹, corresponding to a decrease of K_OW between 1.15- and 1.32-fold per 10 …