Diethyl ketone triperoxide: thermal decomposition reaction in chlorobenzene solution and its application as initiator of polymerization

Abstract

The kinetics of the thermal decomposition reaction of diethyl ketone triperoxide (3,3,6,6,9,9‐hexaethyl‐1,2,4,5,7,8‐hexaoxacyclononane, DEKT) in chlorobenzene solution were studied in the temperature range 99.0–148.0°C and at initial concentrations of (1.65–4.97) × 10−2 M. The thermolysis of DEKT follows a first‐order kinetic law up to at least ca 80% triperoxide conversion. The activation parameter values for the initial O—O bond rupture in chlorobenzene (ΔH‡=134.6±1.7 kJ mol−1; ΔS‡ = 4.2 ± 3.8 J mol−1 K−1) and the reaction products observed support a stepwise reaction mechanism which includes as a first step the unimolecular homolytic cleavage of one peroxidic bond of the DEKT molecule giving rise to a biradical as intermediate. Additionally, the results obtained were compared with those obtained in toluene, toluene–styrene (50%, v/v) and chlorobenzene–styrene (50%, v/v) solution, showing that the decomposition reaction is strongly solvent dependant. Further, the biradical intermediate obtained in all cases was used to initiate styrene polymerization. It was demonstrated that DEKT can effectively act as initiator in styrene polymerization and its performance is similar to that presented by a multifunctional initiator giving rise to high molecular weight polystyrene at a high reaction rate. Copyright © 2004 John Wiley & Sons, Ltd.

Thermal decomposition of diethyl ketone triperoxide in methyl methacrylate: Theoretical and experimental study of the initial solvation state and its influence on the polymerization process

“…In this regard, Cañizo et al . reported the thermal decomposition of DEKTP at 130°C in styrene (St), toluene‐St and chlorobenzene‐St (both mixtures at a volume ratio of 50:50), and the k d values reported were 1.53 × 10 −3 , 5.65 × 10 −4 and 4.68 × 10 −4 s −1 , respectively . Meanwhile, Barreto et al .…”

“…The multi‐functional cyclic peroxides can be obtained through the reaction of hydrogen peroxide with ketone compounds at low temperatures (−10, −15°C), using an inorganic acid, such as sulfuric acid, as a catalyst. Regarding the thermal decomposition kinetics of some cyclic organic peroxides, it has been extensively reported . For instance, the thermolysis of pinacolone diperoxide [PDP, 3,6‐ditertbutyl‐3,6‐dimethyl‐1,2,4,5‐tetraoxacyclohexane, [Figure (a)], acetone cyclic triperoxide [ACTP, 3,3,6,6,9,9‐hexamethyl‐1,2,4,5,7,8‐hexaoxacyclononane, [Figure (b); R= CH 3 )] and diethyl ketone triperoxide [DEKTP, 3,3,6,6,9,9‐hexaethyl‐1,2,4,5,7,8‐hexaoxacyclononane [Figure (b); R = CH 2 CH 3 )] has been reported in different organic solvents (or mixtures of them), including acetone, toluene, ethylbenzene, chlorobenzene, acetonitrile, ethanol, among others.…”

“…All the early works have mainly focused on the decomposition behavior of these initiators in organic solvents with different physico‐chemical characteristics (protic or aprotic; polar or non‐polar), and it has been demonstrated that the decomposition reaction is strongly solvent‐dependent, due to variations in the molecular interactions that modify their solvation capabilities . Therefore, the decomposition rate constant ( k d ) of DEKTP at 150°C in toluene (1.6 × 10 −4 s −1 ) is approximately three times lower than that in acetonitrile (4.79 × 10 −4 s −1 ) at the same temperature .…”

Cyclic organic peroxides thermal decomposition in the presence of CuFe2O4 magnetic nanoparticles

“…In previous works, it was demonstrated that different peroxides have application as polyfunctional initiators in styrene and methylmethacrylate polymerization [8][9][10]. For example, the use of diethylketone triperoxide allowed obtaining high monomer conversions in short times (100% for methylmethacrylate [10] and 30% for styrene [8] in 50 min at 130 • C) with an increase in final polymeric product molecular weights, compared with typical monofunctional initiators.…”

Thermal decomposition reaction in ethanol solution of deuterated acetone cyclic diperoxide and acetone diperoxide. Secondary inverse isotopic effect

“…This behavior allows to obtain polymers with high molecular weights, in a lower polymerization time and with improved mechanical properties than those obtained with mono-or bifunctional classic initiators. 2,7 In previous works, it was demonstrated that an important substituent effect is operative on kinetic and activation parameters of the thermal decomposition reaction of substituted tetraoxacyclohexanes derived from acetone, pinacolone, 4-heptanone, benzophenone, dibenzylketone, cyclohexanone or acetophenone in different organic solvents. 3,[8][9][10][11] It has been widely published that the rate-determining step of the thermal decomposition reaction of the cyclic peroxides is the biradical intermediate formation (Eq.…”