Construction of phase diagrams to estimate phase transitions at high pressures: A critical point at the solid liquid transition for benzene

Ibrahimoglu B., ÜNER D., Veziroglu A., Karakaya F., Ibrahimoglu B.

INTERNATIONAL JOURNAL OF HYDROGEN ENERGY, vol.46, no.29, pp.15168-15180, 2021 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 46 Issue: 29
  • Publication Date: 2021
  • Doi Number: 10.1016/j.ijhydene.2021.02.010
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, PASCAL, Artic & Antarctic Regions, Chemical Abstracts Core, Communication Abstracts, Environment Index, INSPEC
  • Page Numbers: pp.15168-15180
  • Keywords: Phase diagram, Graphical method, Pressure range of liquid phase, Critical pressure, Metastable phase, Plasma, MEMBRANE FUEL-CELL, HYDROGEN, STORAGE, PERFORMANCE, WATER, SYSTEM, GAS
  • Middle East Technical University Affiliated: Yes


Phase diagrams are an integral part of the estimation of material properties in the case of high temperature and pressure. The pressure-temperature (P-T) phase diagram is used to determine the state of aggregation (solid, liquid, gaseous) of a substance under given conditions. This article presents a method to reveal new states in the phase diagram, including the possibility of the plasma state. Using the empirical data of benzene, a critical pressure beyond solid-liquid equilibrium was estimated. It is highly probable that beyond these pressures, benzene may ionize and exhibit plasma behavior. The method proposed in this work for benzene could also be applied to create a comprehensive phase diagram of Hydrogen at certain pressure and temperature. Because the complex behavior of hydrogen, as well as the constant discovery of new varieties and the creation of many different phases of hydrogen makes it very difficult to construct a realistic phase diagram.