Abstract A detailed scheme for the mechanism of chain oxidation of hydrocarbons in the liquid phase, completed with additional elementary steps of chain generation, propagation and branching, is given here.
The formation of radicals in the course of the reaction occurs by hydroperoxide decomposition at the 0-0 bond as well as by interaction of hydroperoxide with the initial hydrocarbon and with the oxidation products.
Along with the basic reaction, that between peroxide radicals and the hydrocarbon, at high degrees of conversion of importance become the elementary reactions of R02 with hydroperoxides and alcohols.
The rate constants for these reactions as well as for the chain termination steps have been determined for a number of compounds. Another route of chain propagation namely isomerization and decomposition of the peroxide radical accompanied by cleavage of the C-C bond (same as for gaseous oxidation of hydrocarbons) may occur under the catalytic action of the reactor wall.
The importance of solvation of peroxide radicals in the oxidation of hydrocarbons has been established.
It was found lowering of the dielectric constant of the medium, as well as formation of hydrogen bonds, results in a lower reactivity of the ROz radicals. The fundamental kinetics of oxidation in homogeneous reactors (in open systems) have been revealed.
The mechanisms of liquid phase oxidation of butane and the preparation of propene oxide and other products of conjugated oxidation reactions have been studied and their efficiency has been evaluated. It was found that epoxydation of olefines occurs by interaction between acyl peroxy radicals with a double bond.
The possibilities for carrying out new processes based on utilization of the properties and peculiarities of degenerate branched reactions are discussed.
Résumé Un schéma détaillé d'oxydation en chaîne des hydrocarbures en phase liquide est donné. Le schéma est completé par des stades nouveaux d'initiation, de propagation et de branchement des chaînes. I1 est établi que l'initiation des chaîne suit le méchanisme termoléculaire.
A partir de moment quand les hydroperoxydes sont formés les radicaux libres se forment au cours de decomposition d'hydroperoxyde par rupture de liaison 0-0 (une réaction monomoleculaire aussi que par réaction de I'hydroperoxyde avec l'hydrocarbure où même avec les produits dloxidation.
A coté de la réaction fondamentale de propagation de chaine (interaction entre R02 et l'hydrocarbure) on observe des réactions de R02 avec les hydroperoxyde et les alcohols.
Les constants de vitesse de ces stades élementaires aussi que les constantes de rupture de chaîne ont été determunées pour quelques substances élementaires.
Une route additionelle de propagation de chaînel'isomérisation et la décomposition du peroxy radical accompagnée par rupture de la li