Critical temperature phosgene

I he critical properties of phosgene have been determined expert menially. , x M The method of Vow les has been used to esilmatr the other critical temperatures with a probable ei for of less than 5 C. and live critical densities within 0.01 gramcmilliliter The critical pressures w-erc estimated by the method ol Lvdeison. C [Pg.26]

The density of phosgene has been measured up to its critical point.1 The room temperature densities of ihc other three vempvundu urv rcpvrUad in thv hwrutur. 11 The methud of Ly-dersuti, Grecnkom. and Hougcn has been used to estimate the densities up to the critical temperature 1 The error ia normally 1 3< ... 

Between 0 "C and the critical temperature, the vapour pressure data of phosgene have been summarized by Equation (6.6) (T in K) [744] and, for data above atmospheric pressure, by Equation (6.7) [1843] ... 

Only a few of the physical properties of COBrF have been measured. Carbonyl bromide fluoride (relative molecular mass 126.91) is a colourless gas, with an odour similar to, but distinguishable from, phosgene [1195]. The melting point at atmospheric pressure of COBrF has been reported as -120 2 C [1196a], and the boiling point as -20.6 "C [1196a]. Its critical temperature occurs at +124 C, and its critical pressure is ca. 6.18 MPa [656a,1751]. 

Thionyl fluoride, a colorless gas with an odor like phosgene, fumes mildly when exposed to moist air and is hydrolyzed very slowly by water. It is soluble in ether and benzene, melts at —129.5°, boils at —43.8°, and reaches the critical point at 89.0° and 55.3 atm.7 In the absence of moisture, pure thionyl fluoride does not attack silicon, magnesium, nickel, copper, zinc, or mercury up to 125°.7 It is reported to attack glass at 400°, but has no effect on iron at this temperature.2... 

The critical properties of phosgene have been reviewed elsewhere [1136,1347a,1613, 1614]. The temperature of disappearance of the meniscus was determined to be 181.8 C the temperature of reappearance, 181.6 "C [744]. Although the value was rounded off to 182 C, it is reasonable to assign the value 181.7 "C. The value of 183 C reported by earlier researchers [860] is considered [1613,1614] to have been derived using a method of inferior accuracy on a sample whose purity was not established. 

The process is a fixed bed gas phase system. The reaction is carried out at temperatures up to 400°C. The reaction is exotherm, so cooling is important. To prevent emission, waste steams of phosgene originating in the production plant are lead over an activated carbon to decompose [30,31]. For both reactions (production and decompostion) a relatively low steam activated, unwashed carbon is used, in spite of the fact that for the production a higher activated carbon gives a better performance. However the type of activated carbon in this application is not very critical. An important characteristics of the activated carbon is the water content, which must be very low. 

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