Alcohol k (2S°C)log A E R e f .k c a l / m a 1 M-ls-l AbstractKinetic parameters of the reaction of ozone with aliphatic alcohols of different structures are obtained. The ratio between the relative reactivities of the primary: secondary: tertiary alcohols was found to be l : 15: 138. The bond energy changes in the same sense as the activation energy. The rate-controlling step of ozone reaction with alcohols is the abstraction of a hydrogen atom being in a-position with respect to the OH group. The pre-exponential factors (A) are calculated by the collision and activated complex methods and compared with the experimentally obtained values. The results from the calculations represent convincing evidence that the mechanism of the rate-controlling step of the reaction is associated with the formation of an activiated complex which has a linear shape ensuring free rotation of its fragments.

The kinetics and mechanism of ozone reactions with aliphatic ethers in CCl4 solution have been investigated with a set of six symmetrical ethers: ethyl, chloroethyl, iso-propyl, n-butyl, iso-amyl, and n-amyl. The corresponding kinetic constants at ambient temperature are 3.1, 0.035, 5.4, 6.3, 6.8, and 7.8 l/(mol s). Upon ozonation of n-butylether the main products are butylalcohol, butylaldehyde (butyric acid), and butylbutyrate. A common precursor of these products is the a -hydrotrioxybutylether. Experimental values of the preexponential factors are compared with those calculated according to the activation complex theory with linear or cyclic form of the activated complex. The cyclic form of the activated complexes is unfavorable because of the kinetic factor. Abstraction of hydrogen atom or the far less probable hydride ion abstraction from a-position in the ether molecules is the rate-determining step of ozonation. The ratedetermining factors are the electron density and geometry of the reaction center and the energy of the a-C-H bonds. 0 1995 John Wiley & Sons, Inc.

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The ratio between the relative reactivities of the prim.:sec.:tert. alcohols are found to be 1:15:138.