Thermal Decomposition of Cyclic Organic Peroxides in Pure Solvents and Binary Solvent Mixtures

MARIÁNGELES IGLESIAS; GASTÓN P. BARRETO; GLADYS N. EYLER; ADRIANA I. CAÑIZO

INTERNATIONAL JOURNAL OF CHEMICAL KINETICS

JOHN WILEY & SONS INC

Lugar: Malden-USA; Año: 2010 vol. 42 p. 347 - 353

0538-8066

The thermal decomposition reaction of acetone cyclic triperoxide, acetone cyclicdiperoxide, 4-heptanone cyclic diperoxide, and pinacolone cyclic diperoxide ca. 0.02 M wasstudied in pure solvents (acetone and 1-propanol) and in binary mixtures of acetone/1-propanolat 150◦C. The kinetics of each system was explored by gas chromatography (GC) at differentsolvent compositions. The reactions showed a behavior accordingly with a pseudo-first-orderkinetic law up to at least 90% peroxide decomposition. The main organic products derivedfrom these thermolysis reactions were detected by GC analysis. Among them, the correspondingketones, methane, ethane, and propane were the main identified products. The rates ofdecomposition of pinacolone diperoxide in the pure solvents were practically independent ofthe solvent characteristics, so it was of no interest to analyze its kinetic behavior in binarysolvent mixtures. In acetone/1-propanol mixtures, the solvation effect on the cyclic peroxidesderived from 4-heptanone and acetone molecules was slightly dominated by specific interactionsbetween 1-propanol and a diradical-activated complex initially formed. This specieswas preferentially solvated by 1-propanol instead of acetone. Specific interactions betweenthe O atoms from the peroxidic bond and the H from the OH in 1-propanol can be taken intoaccount.