Watson correlation

Estimates of the latent heat of vaporization of a pure Hquid at any temperature from a known value at a single temperature are possible by several methods. The known value may be experimental, or it may be estimated by equation 16. Of the methods proposed, the Watson correlation (1), which is both simple and reHable, has found the greatest acceptance ... 

Methods to Estimate pv from Tb Only The modified Watson correlation [2] applies for liquids and solids in the pv range from 10-7 to 760mmHg. This method is based on the Watson equation (8.5.1) and requires the input of the normal boiling point temperature, Tb, and of AHvb. However, the latter property is itself calculated from Tb and from structural parameters. For compounds with pv between 10 and 760mmHg, a method error of 2.5% has been reported, whereas a considerably higher error has been found for compounds with pv below lOmmHg. The method has been illustrated for benzene and DDT [2]. A large number of other Tb/pv correlations have been discussed by Horvath [17]. 

Latent heat, 114-116, 181 Riedel equation for, 115-116 Watson correlation for, 116... 

Watson correlation for latent heat, 116 Wilson equation, 379-381 Work, 11-14, 23-26, 138 of adiabatic compression, 67-68, 235-238 ideal, 549-554... 

Also estimate the heat of vaporization of water at 300°C (572° F) by applying the Watson correlation ... 

Pitzer correlation discussed in Example 1.12. If a heat-of-vaporization value at any other temperature is available, use the Watson correlation (Example 1.12) to obtain the value at the normal boiling point. 

A number of techniques have been developed to estimate the, latent heat of vaporization and, to a lesser extent, the latent heat of fusion and sublimation. A description of these techniques can be found in Reid et al. (1987). One very useful and commonly used method known as the Watson correlation appears below... 

A prerequisite for applying estimation techniques is the knowledge of the compound s boiling point (r, ) and for solids also of the melting point The methods described by Grain (1990), Lyman (1985) and Altschuh, Briiggemann and Karcher (1993) are of general applicability and they are not restricted to particular chemical classes. In Table 4.4, model 1 is derived from the Antoine equation, which describes the temperature dependence of vapour pressure model 2 is based on the Watson correlation, which describes the temperature dependence of the heat of vaporization model 3 constitutes an extension of 2. These three models additionally use a class-specific constant (Kp) as input, which is assumed to describe the polarity of the compounds (Table 4.5). 

Scalar n watson exponent in Watson correlation /0.38/ Scalars... 

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