How can I calculate the boiling temperature of a pure substance as a function of pressure? I want to make an algorithm that will give me the boiling temperature of a substance as a function of pressure, the critical temperature of a substance, and the critical pressure of a substance. I believe this can be done using a combination of the Peng-Robinson Equation of state and the Clayperon or Clausius-Clayperon equation of state. The issue is that I believe this requires additional input criteria, specifically the latent heat but this function is supposed to be more general. Is there any way to work this method without the latent heat, or to calculate the latent heat from the other known values?
If you know the latent heat of vaporization at one temperature, you should be able to determine the latent heat of vaporization at any other temperature from Hess' law and knowledge of the heat capacities of the liquid and vapor as a function of temperature.  You may also have to include a pressure contribution as the critical point is approached.