A comparative study on transetherification of 1,3‐bis(methoxymethyl)imidazolidin‐2‐one derivatives and 1,3‐bis(methoxymethyl)imidazolidine‐2‐thione with the linear cellulose chain under acidic conditions

Abstract The transetherification mechanism of 1,3‐bis(methoxymethyl)imidazolidin‐2‐one ( m ‐DMEU) derivatives and 1,3‐bis(methoxymethyl)imidazolidine‐2‐thione ( m ‐DMTEU) with the hydroxy groups of linear cellulose chain ( n = 1–5) under acidic conditions was executed using the two‐layer ONIOM model and the methods of Møller–Plesset perturbation theory, density functional theory, and semi‐empirical. The stability of intermediate carbocation in water solvent was probed using both the Onsager model and the integral equation formalism version of the polarized continuum model for the purpose of comparison. The computational results confirmed that the transetherification mechanism was belong to the unimolecular nucleophilic substitution (S N 1), it had the triple‐well shape in the gas‐phase on the potential energy surface; the substituent R (R = CH 3 , C 2 H 5 , n ‐C 3 H 7 , C 2 H 5 Cl, C 2 H 5 F) in the derivatives as well as the X‐atoms (X = O, S) impacted significantly on the reactivity. The largest energy barrier was the step that released H + ion. The experimental observation and the experimental data reported in the literature are in good agreement with the computational data.