Estimating pure component vapor pressures of complex organic molecules

Modifications of the entropy of boiling term and heat capacity change upon boiling term are made to the Yalkowsky-Mishra vapor pressure equation. These modifications eliminate a systematic error and enable the pure component vapor pressure estimation of complex organic compounds, including those that-are hydrogen bonding. The new vapor pressure equation, which requires only the knowledge of transition temperatures and molecular structure, is shown to be more accurate than the Yalkowky-Mishra equation for a wide variety of compounds over a wide range of temperatures (vapor pressures from 1 atm and below).