Reaction kinetics of hydrogen addition reactions to methyl butenoate

Abstract

We study the chemical kinetics of hydrogen addition reactions of unsaturated methyl esters, methyl 2-butenoate and methyl 3-butenoate, and compare the rate constants with those of hydrogen abstraction reactions by H atom.

Multistructural Variational Reaction Kinetics of the Simplest Unsaturated Methyl Ester: H-Abstraction from Methyl Acrylate by H, OH, CH3, and HO2 Radicals

“…In addition, they treated the torsion with one-dimensional hindered rotor approximation and neglected the coupling of torsions. Recent studies have demonstrated that the multistructural torsion method is a better choice to treat the torsion for hydrogen abstraction reactions. ,,, Hence, the MS-CVT/SCT method used in this work is an improvement to the calculation and the result is more reliable. Bennadji et al experimentally measured ignition delay times, and the results for reaction R3a inferred from the kinetic model are 2 times larger than our calculations.…”

“…They are chosen due to its good performance on the barrier height and transition-state geometries for hydrogen transfer reactions, and its early success in calculating the bond dissociation enthalpies of C–H and C–C bonds for large esters, especially the B3LYP method . MN15 is a local density functional, which has good accuracy for both valence and Rydberg electronic excitations, and is a more popular method in kinetic calculations recently. ,, Six basis sets were tested. The MG3S basis set is identical to the 6-311+G­(2df,2p) for H, C, and O atoms, which is often combined with the M08HX functional to determine the initial structure of molecules. ,, The choice of the cc-pVTZ basis set is based on the consideration of computational cost and calculation accuracy and is recommended in the literature. ,, Additionally, it is necessary to add suitable diffuse functions to the cc-pVTZ basis set because the weak interactions are involved in this reaction system.…”

“…For the smaller unsaturated FAMEs, only a few theoretical studies on methyl butenoate (MBe, CH 2 CHCH 2 C­(O)­OCH 3 ) , and methyl crotonate (MC, CH 3 CHCHC­(O)­OCH 3 ) were performed. Li et al and Gao et al investigated the H-abstraction and H-addition reaction kinetics of MBe with the H atom using the multistructural canonical variational transition-state theory (TST) with small-curvature tunneling (MS-CVT/SCT) based on the M062X/ma-TZVP-optimized geometries, respectively.…”

“…For the smaller unsaturated FAMEs, only a few theoretical studies on methyl butenoate (MBe, CH 2 CHCH 2 C­(O)­OCH 3 ) , and methyl crotonate (MC, CH 3 CHCHC­(O)­OCH 3 ) were performed. Li et al and Gao et al investigated the H-abstraction and H-addition reaction kinetics of MBe with the H atom using the multistructural canonical variational transition-state theory (TST) with small-curvature tunneling (MS-CVT/SCT) based on the M062X/ma-TZVP-optimized geometries, respectively. Zhou et al explored the H-abstraction and OH-addition reaction kinetics of MC, a key intermediate which can be directly produced from the saturated and unsaturated methyl ester decompositions.…”

Tracking the deprotonation site of dehydroandrographolide with electrospray ionization mass spectrometry by deuteration

“…The ma‐TZVP basis set is a minimally augmented Karlsruhe def2‐TZVP basis set obtained by adding a minimal set of diffuse functions 25 . Additionally, the M06‐2X/ma‐TZVP method has shown good performance in recent studies 26–28 …”