The phosgene-hydrogen halide system

The solubility of phosgene, and of its mixtures with hydrogen chloride, in organic 

Liquid-vapour equilibria in the phosgene-hydrogen chloride system have also been studied in connection with the problems associated with the separation of these two materials during the production of isocyanates. The system has been examined under atmospheric pressure within the range of the boiling points of the materials, ca. 8 to -85 C. The temperature-composition curve is illustrated in Fig. 6.14 [789] it shows large deviations from ideality. 

Vapour pressure-composition isotherms for the COClj-HCl system have been investigated between -75 and 0 C up to a total pressure of about 170 kPa, see Fig. 6.15 [ICI109]. A more detailed study has been published for temperatures of -7.2 (266.2 K) and -79.6 C (193.6 K) [757a] and these are illustrated for both liquid and vapour phases in Table 6.15 and Figs. 6.16(A) and 6.16(B). 

The enthalpies of mixing in the phosgene-hydrogen chloride system have been calculated for the -50 to -75 C temperature region [ICI109]. For Y(HCl) of 0.2, 0.4 and 0.6, the corresponding values of are -100, -218 and 280 J mol , respectively. 

During the production of CFC-11 and CFC-12 from the antimony-catalyzed reaction of CCl with HF, the small amount of moisture in the commercial HF is converted into COClj by reaction with the tetrachloromethane (see Section 5.2.1.2). The accumulation of phosgene 

---