Kinetics Of Secondary Reactions Research Articles

High-Temperature Fluorocarbon Chemistry Revisited.

The thermal dissociation reactions of C2F4 and C2F6 were studied in shock waves over the temperature range 1000-4000 K using UV absorption spectroscopy. Absorption cross sections of C2F4, CF2, CF, and C2 were derived and related to quantum-chemically modeled oscillator strengths. After confirming earlier results for the dissociation rates of C2F4, CF3, and CF2, the kinetics of secondary reactions were investigated. For example, the reaction CF2 + CF2 → CF + CF3 was identified. Its rate constant of 1010 cm3 mol-1 s-1 near 2400 K is markedly larger than the limiting high-pressure rate constant of the dimerization CF2 + CF2 → C2F4, suggesting that the reaction follows a different path. When the measurements of the thermal dissociation CF2 (+Ar) → CF + F (+Ar) are extended to temperatures above 2500 K, the formation of C2 radicals was shown to involve the reaction CF + CF → C2F + F (modeled rate constant 8.0 × 1012 (T/3500 K)1.0 exp(-4400 K/T) cm3 mol-1 s-1) and the subsequent dissociation C2F (+Ar) → C2 + F + (Ar) (modeled limiting low-pressure rate constant 3.0 × 1016 (T/3500 K)-4.0 exp(-56880 K/T) cm3 mol-1 s-1). This mechanism was validated by monitoring the dissociation of C2 at temperatures close to 4000 K. Temperature- and pressure-dependences of rate constants of reactions involved in the system were modeled by quantum-chemistry based rate theory.

The kinetics of secondary reactions in the iodination of monogermane. The effect of iodine substitution on the GeH bond dissociation energy

AbstractA study has been made both of secondary reactions occurring during the reaction of I2 with GeH4, and of the direct reaction between I2 and GeH3I. Both these studies show that the abstraction reaction occurs about 30 times faster than the reaction in the temperature range of 425–446 K. This information is used to show that iodine substitution weakens Ge–H bonds by 14.4 ± 2.5 kJ/mol and that D(H2IGeH) = 332 ± 10 kJ/mol (79.3 kcal/mol). Possible reasons for the effects of halogen substituents on GeH and SiH bond strengths are discussed.

The Kinetics of Secondary Reactions in the Catalytic Cracking of Paraffins

The Kinetics of Secondary Reactions in the Catalytic Cracking of Paraffins

Reactions of α-oxides: Kinetics of secondary reactions in ethylene oxide-acetic acid interaction

Reactions of α-oxides: Kinetics of secondary reactions in ethylene oxide-acetic acid interaction