Rate coefficient dioxolane

Special attention must be given to acetals and ketals in which the central carbon and the two oxygens are part of a five- or six-membered ring. A large amount of experimental work in this field has been done recently, mainly by Fife and his associates. Rate coefficients and activation parameters for the hydrolyses of some cyclic acetals and ketals can be found in Tables 12 and 13. For the 1,3-dioxolanes (= ethylene acetals or ketals), the rate coefficient is 1.5 to 4.4 powers of ten lower than for the corresponding diethyl acetals or ketals, respectively. The entropies of... 

Yamashita [128] reports that the kinetics of polymerization of 1,3-dioxolane initiated by BF3. Et2 O are quite complex and that initiation is not a simple reaction. In 1973 Rozenberg et al. [130] reported a kinetic study of such a polymerization in CHjClj solution. They e ain found an induction period, but this time stated that the acceleration is the result of the autocatalytic action of the macromolecules formed. Their conclusions are based (i) on the relationship of the rate coefficients of BF3. Et2 0 reactions with cyclic monomer or with polymer chain and (ii) on the decrease of the induction period on addition of polymer or methylal to a polymerizing mixture. The mechanism of initiation suggested is... 

Table lll-E-l I. Rate coefficients (k = Ax cm molecule s ) for reaction of OH with 1,3-dioxolane... 

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