Density functional theory calculation on the C-H bond insertion reaction of dibromocarbene with acetaldehyde

Abstract

The insertion reaction mechanism of CBr 2 with CH 3 CHO has been studied by using the B3LYP/6-31G(d) method. The geometries of reactions, transition state and products were completely optimized. All the energy of the species was obtained at the CCSD(T)/6-31G(d) level. All the transition state is verified by the vibrational analysis and the internal reaction coordinate (IRC) calculations. The results show that the propionaldehyde ( H P1) is the main product of CH 2 insertion with CH 3 CHO. The calculated results indicated that all the major pathways of the reaction were obtained on the singlet potential energy surface. The singlet CBr 2 not only can insert the C α -H [reaction I(1)]) but also can react with C β -H [reaction II(1)]. The statistical thermodynamics and Eyring transition state theory with Wigner correction are used to study the thermodynamic and kinetic characters of I(1) and II(1) in temperature range from 100 to 2200 K. The results show that the appropriate reaction temperature rang is 250 to 1750 K and 250 to 1600 K at 1.0 atm for I(1) and II(1) respectively. The rate constant and equilibrium constant are distinct in the range from 250 to 1000 K so that I(1) more easily occurs, while the reactions are not selected in the temperature range of 1000-1600 K.

Quantum chemical study on insertion and abstraction reaction of dichlorocarbene with methyl alcohol and methyl mercaptan

“…ReactionⅠ(3) is a strong exothermal reaction with H5 and H6 being both abstracted, resulting in product P4(CH 2 O+CH 2 Cl 2 ). respectively, which indicates that the insertion reaction of CCl 2 with O-H and C-H in CH 3 OH possesses the electophilic and neucleophilic characters, and these results are consistent with not only the characters of insertion reaction carbene with hydrocarbon and aether [8,21] , but also the characters of CBr 2 insertion with the C α -H in CH 3 CHO [10] , except that reactionⅠ (3) Figure 1.…”

“…In the past several years, the AIM theory has been widely applied to the study of the electron structures of molecule, chemistry bonds and chemical reactions [16−18] . The insertion reactions of CX 2 (X=Cl, Br) with C-H in formaldehyde and acetaldehyde have also been studied systemically and some interesting results have been obtained [3,9,10] . In order to explore the rules of insertion and abstraction reaction between carbene and the alcohol and further understand their mechanisms, in this paper, the reaction pathways and the mechanisms of singlet and triplet CCl 2 abstracting H reaction and the insertion reaction with the C-H and M-H (M=O, S) in methyl alcohol and methyl mercaptan are studied by using B3LYP/6-311G (d, p).…”

Chemically assembled monolayers of fluorophores as chemical sensing materials

“…When a much longer spacer was employed in the functional film as in the case of Film P-5 containing triethylenetetramine group in its spacer, its sensing behavior was mainly correlated with the saturated vapor pressure of NACs. 45 The sensitivity of this film toward different NAC vapors went as follows: NB (nitrobenzene) > NT (nitrotoluene) > DNT (2,4-dinitrotoluene) > TNT (2,4,6trinitrotoluene) > PA (picric acid, 2,4,6-trinitrophenol), which is in agreement with the order of saturated vapor pressures of each NAC (2.70 Â 10 À1 , 1.64 Â 10 À1 , 1.74 Â 10 À4 , 8.02 Â 10 À6 and 5.8 Â 10 À9 mmHg for NB, NT, DNT, TNT, and PA at room temperature, respectively). Although it exhibited slower response to the presence of NAC vapors compared to those with shorter spacers, it featured an approved selectivity towards nitrobenzene.…”

Theoretical Study of the Mechanism of the ¹CBr₂ + ³O₂ Reaction

“…Skell and Garner reported the reactivity in olefin-dibromocarbene reactions experimentally [8]. Theoretically, the reaction mechanisms of 1 CBr 2 with HCHO, CH 3 CHO, p-CH 3 PhCOCH 3 and CH 3 OH were studied recently [9][10][11][12][13].…”