Sonntag equation

Ine Sonntag equation strictly only applies to water vapor with no other gases present (i.e., in a partial vacuum). The vapor pressure of a gas mixture, e.g., water vapor in air, is given by multiplying the pure liquid vapor pressure by an enhancement factor/, for which various equations are available (see British Standard BS 1339 Part 1, 2002). However, the correction is typically less than 0.5 percent, except at elevated pressures, and it is therefore usually neglected for engineering calculations. 

From Sonntag equation (12-4),p, = 19,948 Pa difference from Antoine is less than 0.5 percent. Relative humidity = 100 x 3915/19,948= 19.6 percent. From a psychrometric chart, e.g.. Fig. 12-1, a humidity of 0.025 kg/kg at T = 60°C lies very close to the adiabatic saturation line for 35°C. Hence a good first estimate for Tas and T b will be 35°C. Refining the estimate of Twb by using the psychrometer equation and iterating gives... 

A few studies have been carried out on the parent four- and five-membered cyclic sulfones—for thietane 1,1-dioxide (30) by Scala and Colon and for thiolane 1,1-dioxide (sulfolane) (31) by Honda and coworkers and, later, by Schuchmann and von Sonntag . In the former compound, the major photochemical process, in the vacuum UV range, is the initial production of a trimethylene (CjHg) biradical and SO2 (equation 9). In both the solid- (77 K) and gas-phase photolyses, formation of a triplet biradical appears to be favored. As well as the expected cyclopropane and propylene, ethylene is also obtained during these photolyses, presumably by a cycloreversion process (equation 10). 

Von Sonntag and coworkers14 repeated Michael and Hart s study of the reaction of OH radical with 1,3- and 1,4-cyclohexadienes and extended it. They found that in the case of 1,4-cyclohexadiene, 50% of the OH radicals abstract an hydrogen atom, while only about 25% of the OH radicals abstract an hydrogen atom from 1,3-cyclohexadiene. The remaining OH radicals probably add to the double bond. The addition to the double bond was confirmed by final products analysis in the case of the 1,4-isomer. When N20-saturated aqueous solution of 1,4-cyclohexadiene (10-2 M) together with lower (10-4 M) concentration of the thiol (1,4-dithiothreitol) was y-radiolysed, it was found that 4-hydroxycyclohexene was produced with a yield of 0.29 prnol J 1, i.e. a yield of 50% of the OH radicals (equation 9). 

In their excellent review of multicenter photochemical reactions, Warrener and Bremner (1966) classify reactions by the number of participating centers, e.g. nC. When orbital overlap of nonadjacent centers is involved, the label XnC refers to orbital overlap in alternate centers. In equation (48) or (49) (Srinivasan and Sonntag, 1965) there... 

The 1,3-cyclohexadiene could not be prepared with higher purity than 98% and hence the analysis based on the final products is less meaningful. The yield of 3- and 4-hydroxycyclohexenes show that only 31% (0.18 pmolJ /0.58 pmolJ ) of the OH radicals add to the double bonds. There is no information about the missing 44% (100% — 25%—31%). Von Sonntag and coworkers suggested that the yield of hydroxy cyclohexenes is not indicative of the OH addition to the double bonds due to non-quantitative reaction of the ally lie radical 1 (equation 10) with RSH. Since, in the case of 1,4-cyclohexadiene, they found complete material balance, they concluded that the alky lie radical formed in reaction reacts quantitatively with the thiolic compound. Thus, radical 2 formed in reaction (11) will react quantitatively with RSH. The inefficiency of the reduction of the allylic radical by the thiol is probably due to the weak ally lie C—H bond which leads to a six orders of magnitude lower rate constant for the RSH-I- allylic radical reaction compared with the RSH-I- alkyl radical reaction. If all the material imbalance is due to incomplete reduction of the allylic radical, its formation is the main path of reaction of OH with 1,3-cyclohexadiene. 

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