Theoretical studies of isomerization barriers of 2-pentoxy radical and its products

This article deals with the calculation of isomerization reaction of 2-pentoxy radical via its possible processes to form the stable products by density functional theory. We studied the intramolecular hydrogen transfers from the five carbon positions to the oxygen atom of 2-pentoxy and then followed by successive transfers from the unstable hydroxy radical to the final stable one. There are five paths of hydrogen transfer discussed, which include the transition structures of pseudo three-, four-, five-, and six-membered rings. The results indicated that the rate constant of the process via six-membered ring transition state calculated at the B3LYP/6-311++G** level was close to the experimental value and it had the lowest calculated energy barrier among all, 8.63 kcal/mol. We also studied the isomerization barriers of the first-stage product to form the most stable conformation via possible paths. The calculated lowest barrier was 18.41 kcal/mol via a five-membered ring process.