Ozone reactions with aliphatic ethers in CCl₄. Kinetics and mechanism

Abstract

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.

Kinetics and Mechanism of the Ozone Reaction with Alcohols, Ketones, Ethers and Hydroxybenzenes

“…5) is complicated and this implies that ozone reacts with more than one compound [1,26,27]. The two horizontal sections of the curve are the result of the interaction of ozone with two compounds, the rate constants of which differ considerably.…”

“…In fact, the literature values for some of these constants are of this order, but they have been measured by a modified stop-flow technique [32]. The analyses made so far show that the reaction path of the ozone reactions with dihydroxybenzenes depends strongly on their nature and they precede via transition states with activated complex -LC-I or LC-II.…”

“…Moreover, the considered interactions are extremely important from an ecological point of view for the utilization and purification of industrial wastewaters, originating from hydroxybenzene production, through their partial or complete oxidation . The importance of this process for theory and practice gave us an impetus to carry out systematic investigations [25][26][27][28][29][30][31][32][33][34][35]. The aim of the present paper is to determine the ozonolysis rate with the above cited oxygen-containing organic compounds and to clarify the role of oxygen in mechanism and reaction ability.…”

Ozone and its Reactions with Diene Rubbers

“…Because of the high viscosity and high value of rate constants the reaction takes place either in the diffusion or in the mixed region. In order to obtain correct kinetic data we have used the theory of boundary surface [30]: It was found out that the relative viscosity decreases exponentially upon ozonation of SKD solutions (Fig. 1).…”

Facile Ozonation of Light Alkanes to Oxygenates with High Atom Economy in Tunable Condensed Phase at Ambient Temperature

“…Ozone attacks most organic solvents more readily than it activates alkanes, which adversely affects the efficient utilization of ozone. Solvents such as chlorocarbons − and fluorocarbons − display enhanced resistance to ozone. However, these solvents pose environmental concerns. , While acetic acid can serve as a more environmentally benign solvent that is resistant to ozone oxidation, this solvent acts as a radical scavenger and thus does not act as an innocent solvent .…”