Theoretical reinvestigation of the ozonolysis mechanism of allyl alcohol

Abstract

AbstractAllyl alcohol (AA) is the simplest unsaturated alcohol. Ozonolysis is one of the key removal processes for AA in the atmosphere. However, a recent theoretical study suggests that the ozonolysis of AA cannot feasibly occur in atmospheric conditions because of the high barrier (~96 kcal/mol) involved in the primary ozonide (POZ) decomposition. In this work, the ozonolysis mechanism of AA was reinvestigated theoretically. The computed barrier for POZ decomposition is only ~20 kcal/mol. Therefore, the AA ozonolysis can take place in the atmosphere, consistent with the experimental conclusions. Moreover, two new Criegee intermediates (syn‐ and anti‐AA‐CI) were found to be produced in this reaction. The wave function analyses indicate that there exists an intermolecular hydrogen bond in syn‐AA‐CI, which significantly affects its unimolecular decomposition and reactions with H2O. Compared with the normal reactions of anti‐CI‐AA, the stabilized syn‐AA‐CI has two distinct isomerization channels: (i) addition of OH group to the reactive sites of CI forming an ethylene oxide (HOOCH2OCH2) and (ii) double H‐transfer producing HOOCH2CHO. Meanwhile, the addition of H2O in syn‐AA‐CI also exhibits two different pathways. One is the unique addition‐coupled double H‐transfer, and the other is the addition‐coupled single H‐transfer, both leading to the formation of CH2(OH)CH(OH)OOH.