polykin.properties.vaporization

DHVL_Watson

DHVL_Watson(
    hvap1: float, T1: float, T2: float, Tc: float
) -> float

Calculate the variation of the vaporization enthalpy of a pure compound with temperature using the Watson method.

\[ \Delta H_{v,2} = \Delta H_{v,1} \left(\frac{1-T_{r,2}}{1-T_{r,1}}\right)^{0.38} \]

where \(T_{r,i}=T_i/T_c\).

References

• RC Reid, JM Prausniz, and BE Poling. The properties of gases & liquids 4th edition, 1986, p. 228.

PARAMETER	DESCRIPTION
hvap1	Vaporization enthalpy at T1 [Any]. TYPE: float
T1	Temperature corresponding to hvap1 [K]. TYPE: float
T2	Temperature at which the vaporization enthalpy is to be computed [K]. TYPE: float
Tc	Critical temperature [K]. TYPE: float

RETURNS	DESCRIPTION
float	Vaporization temperature at T2 [hvap1].

Examples:

Estimate the vaporization enthalpy of vinyl chloride at 50°C from the known value at the normal boiling temperature.

>>> from polykin.properties.vaporization import DHVL_Watson
>>> DHVL = DHVL_Watson(hvap1=22.9, T1=258.0, T2=273.15+50, Tc=425.0)
>>> print(f"{DHVL:.1f} kJ/mol")
19.0 kJ/mol

Source code in src/polykin/properties/vaporization/dhvl.py

def DHVL_Watson(
    hvap1: float,
    T1: float,
    T2: float,
    Tc: float,
) -> float:
    r"""Calculate the variation of the vaporization enthalpy of a pure compound
    with temperature using the Watson method.

    $$ \Delta H_{v,2} = \Delta H_{v,1}
       \left(\frac{1-T_{r,2}}{1-T_{r,1}}\right)^{0.38} $$

    where $T_{r,i}=T_i/T_c$.

    **References**

    *   RC Reid, JM Prausniz, and BE Poling. The properties of gases & liquids
        4th edition, 1986, p. 228.

    Parameters
    ----------
    hvap1 : float
        Vaporization enthalpy at `T1` [Any].
    T1 : float
        Temperature corresponding to `hvap1` [K].
    T2 : float
        Temperature at which the vaporization enthalpy is to be computed [K].
    Tc : float
        Critical temperature [K].

    Returns
    -------
    float
        Vaporization temperature at `T2` [hvap1].

    Examples
    --------
    Estimate the vaporization enthalpy of vinyl chloride at 50°C from the known
    value at the normal boiling temperature.
    >>> from polykin.properties.vaporization import DHVL_Watson
    >>> DHVL = DHVL_Watson(hvap1=22.9, T1=258.0, T2=273.15+50, Tc=425.0)
    >>> print(f"{DHVL:.1f} kJ/mol")
    19.0 kJ/mol
    """
    return hvap1 * ((1 - T2 / Tc) / (1 - T1 / Tc)) ** 0.38