Scheme 3.

Peroxy radicals produced in the reaction of OH with 2-hexanol produce organonitrates (RONO₂, blue boxes) after reaction with NO, in a branching ratio measured here to be ∼25% at 296 K. Reaction with HO₂ produces hydroperoxides (ROOH). In competition with bimolecular chemistry, the 2,4 RO₂ undergoes a unimolecular H-shift to produce QOOH. By measuring the changing yield of the 2,4 and 2,5 RONO₂ isomers relative to that of the 2,3 RONO₂, an isomer that isomerizes negligibly under the conditions of these experiments, we experimentally constrain the H-shift rate constant. The chemistry of the 2,5 RO₂ radical (not shown) parallels that of the 2,4 isomer.