The role of ammonia and amines in the isomerization of Criegee intermediates: A theoretical study

[Display omitted] •Two different participation modes are considered in the isomerization of CIs.•Catalyst molecules act as bridges to increase the reactivity of the reactants.•The catalytic effect of amines is related to the number of their substituents. The isomerization of Criegee intermediates (CIs) is investigated using quantum chemistry calculations with the help of ammonia and amines. Two different participation modes (indirect/direct participation) for ammonia and amines are considered in the isomerization of the CIs. The results indicate that CIs whose structures are similar to syn-CH3CHOO are more prone to isomerize in comparison with CIs similar to anti-CH3CHOO. Ammonia and amines as catalysts can promote CI isomerization, especially the effect of amines is more prominent. Moreover, the catalytic effect of amines is consistent with its basic strength, that is, ethylamine