Determination of the gas-phase decomposition rate constants of heptyl-1 and heptyl-2 hydroperoxides C7H15OOH

✍ Scribed by K. A. Sahetchian; A. Heiss; R. Rigny; R. I. Ben-aïm

• Publisher: John Wiley and Sons
• Year: 1982
• Tongue: English
• Weight: 557 KB
• Volume: 14
• Category: Article
• ISSN: 0538-8066
• DOI: 10.1002/kin.550141205

✦ Synopsis

The gas-phase decomposition of n-heptyl-1 and n-heptyl-2 hydroperoxides C ~H I ~O O H , which split into two radicals C7H15O and OH, has been investigated in the temperature range of 250-360°C. The decomposition has been carried out in a hydrogen-oxygen mixture (the hydroperoxide represents about 50 ppm) so as to avoid secondary reactions between the formed radicals and the reactants. Although the HrO2 mixture is not spontaneously reactive in our conditions, it operates the transformation, through a fast and well-known process, of the OH radicals into HOz radicals and then into H202. However, C7H150 radicals are also transformed into HO2 radicals and then into H202, but through an unknown process. To avoid heterogeneous reactions, vessel and probe are coated by Bz03 and then treated by the slow combustion of hydrogen at 510OC and 250 torr before the experiments are performed. As the reaction scheme is very simple, due to the use of the Hz-02 mixture, the determination of the evolutions of the HOz concentration (followed by electronic paramagnetic resonance) lead to the determination of the gas-phase decomposition rate constant of hydroperoxides. For the n-heptyl-1 hydroperoxide the rate constant is (1.1 f 0.25) X 10l6 exp -(43,500; 1000) s-l and for the n-heptyl-2 hydroperoxide it is (41,500 f 1000) s-l (7 f 2) x 10'5 exp -RT * Mail should be addressed to A. Heiss and should specify Tour 55, 4A btage at the above University.