GROUP CONTRIBUTION METHOD TO PREDICT CRITICAL TEMPERATURE AND PRESSURE OF HYDROCARBONS.

A group contribution model was developed to predict critical pressures and critical temperatures of hydrocarbons using second-order, Benson-type groups. The critical temperature model utilizes the normal boiling point and the groups present in the molecule as parameters. When compared to established methods published by Lydersen and Ambrose, the model produces more accurate results for all families of hydrocarbons except alkanes. The critical pressure model uses the normal boiling point, the critical temperature, and the groups present in the molecule as parameters. The results again are more accurate than the Ambrose or Lydersen models using either an experimental critical temperature or a critical temperature estimated by using the model developed in this study.