Bawn equation

Analogously, intramolecular hydrosilation reactions have been carried out with alkenes cyclization of alkenyloxy-silanes catalyzed by thiols <1998J(P1)467> and by Pt <1996TL827> has been described. In addition, intramolecular temporary silicon-tethered rhodium-catalyzed [4- -2- -2]-cycloisomerization reactions have been carried out by Evans and Bawn (Equation 50) <2004JA11150>. 

C. Reaction Forming a Liquid Product-the Bawn Equation. A rate equation proposed by Bawn is applicable to reactions of solids forming gaseous and liquid products. In the latter case, the reaction rate is described by summing the reaction rates in the solid state and those in the solution formed by the liquid product ... 

Figure 25. Decarboxylation of 5-(tetradecyloxy)-2-furoic acid plotted according to the Bawn equation (90°C). A = (Ski - Sks - k,) / k,. (Reproduced from Ref. 282 with permission.)...

Figure 26. Decarboxylation of octyloxy furanoic acid plotted according to the Bawn equation.

Bawn [101] has proposed a kinetic equation for reactions of solids involving melting. He considered the situation where reactant A is soluble in product B with solubility, s. When the extent of decomposition is a, the fraction of A in the liquid phase is as, and in the solid phase is (1 - ar - a ). If the rate coefficients for reactions in the solid and in the liquid phases are k, and A , respectively, then ... 

Bawn and Williamson [9] examined the catalyzed oxidation of acetaldehyde in solution in acetic acid at 25°C. Whereas uncatalyzed oxidation has mediocre reproducibility, catalyzed oxidations are reproducible within 2%. The catalyst was cobalt acetate in solution in the cobaltous form. The partial oxygen pressure varied from 550 to 950 torr. Under such conditions, as in the case of photochemical oxidations, the stoichiometry of the reaction follows the overall equation... 

Figure 35.6 Dependence of p /p° on volume fraction of polymer. Curves a, b, and c are Raoult s law, Eq. (35.11), for p = 1, 100, and 1000, respectively. Curve d is Flory s equation, Eq. (35.9). Curvee is Eq. (35.14) with w/kT = 0.38. The experimental points are for the system poly-styrene/toluene O, 25°C A, 60°C , 80°C. (Adapted from E. A. Guggenheim, Mixtures. London Oxford University Press, 1952. Data from Bawn, Freeman, and Kamaliddin, Trans. Faraday Soc. 46 677, 1950.)...

The oxidation of benzaldehyde in the presence of cobaltous acetate has been studied in detail by Marta, Boga and co-workers [226-230]. A radical chain mechanism was involved and inhibition of this reaction both by jS-naphthol and by cobaltous ion at high concentration, have been observed. The initiation step was found to involve the decomposition of a Co CPhCOaH) complex to give Co species which were the reactive intermediates. The rate constant and heat of formation of the Co (PhC03H) complex were determined. Bawn and Jolley [225] have shown that at low Co concentration, the oxidation of benzaldehyde follows rate law, equation (177). 

---