Correlation 39 (Watson, Meyra)

The following table lists the identification numbers of this correlation with respect to some well-known sources of thermodynamic data.

The equation has the following form:

You must use at least three coefficients with this correlation.

You can use up to seven coefficients with this correlation.

To make this correlation equivalent to the simplified form of the Watson equation1, you should use only three coefficients with the following equivalences:

• C1 = DHV(T1)

• C2 = T1

• C3 = 0.38

To make this correlation equivalent to an alternative form of the Watson equation, you should use the following coefficient equivalences:

• C1 = DHV(T1)

• C2 = T1

• C3 = A

• C4 = B

• C5 = C7 = 0

• C6 = Tc

To make this correlation equivalent to the equation from Meyra et al.2, you should use the following coefficient equivalences:

• C1 = DHt

• C2 = C6 = Tt

• C3 = Zc

• C4 = Zc2

• C5 = 0

• C7 = 2Tc – Tt

These equivalences use the following nomenclature:

DHV(T1) is the latent heat of vaporization at the triple point

DHt is the latent heat of vaporization at the triple point

Tc is the critical temperature

T1 is a reference temperature

Tt is the triple point temperature

Zc is the universal critical ratio (0.292 according to Guggenheim3)

Usage

We recommend that you use this correlation to calculate only the following property:

• Latent Heat of Vaporization

References

1. Watson, K. M. Thermodynamics of the Liquid State. Ind. Eng. Chem. 1943, 35 (4), 398-406.

2. Meyra, A. G.; Kuz, V. A.; Zarragoicoechea, G. J. Universal behavior of the enthalpy of vaporization: An empirical equation. Fluid Phase Equilib. 2004, 218 (2), 205-207.

3. Guggenheim, E. A. The Principle of Corresponding States. J. Chem. Phys. 1945, 13 (7), 253–261.