OXIDATION OF SATURATED-HYDROCARBONS IN THE CR(VI)-CL--H-H2O SYSTEM WITH TRANSFER OF THE REACTION IN LIGHT FROM SOLUTION INTO THE GAS-PHASE()

The kinetics and substrate selectivity of the first stage of the oxida tion of saturated hydrocarbons (RH) in aqueous solutions Cr(VI)-Cl--H2 SO4 are investigated at 25 degrees C. In the absence of the Cl- ions a t [H2SO4] less than or equal to 38 wt%, the reaction proceeds in solut ion via the ''ore-attack'' mechanism. The Cl- ions retard the reaction . In the system containing [Cr(VI)] = 0.2 - 0.5 mol/kg, [H2SO4] = 8.5 - 16 wt%, [Cl-] = 0.3 - 3.0 mol/kg, and the gas phase (g) over the sol ution (s), the oxidation of RH in the light at 90 degrees C proceeds v ia another mechanism: [GRAPHICS] In solution under the action of Cr(VI ) and sunlight, chlorine is formed that passes into the gas phase and, on photodissociation, gives the Cl atoms, which interact with RH. Thi s scheme is confirmed by the following facts: (1) both Cl-2 formation and RH oxidation proceed only in the light; (2) RH oxidation begins up on Cl-2 accumulation in the gas phase and continues upon interruption of reactor shaking; and (3) the substrate selectivity of the process i s close to the selectivity of the gas-phase RH + Cl-. reaction.