A snapshot of the formation of hydrogen bond between water molecules and the hydroxyl groups of the graphene oxide. Red, blue, and green colors correspond to oxygen, hydrogen, and carbon atoms, respectively. Dashed line show the hydrogen bond.

The multichannel thermal decomposition of acetone is studied theoretically. The isomerization of acetone molecule to its enol form, 1-propene-2-ol, is of especial interest in this research. Steady-state approximation is applied to the thermally activated species CHCOCH* and CHC(CH)OH*, and by performing some statistical mechanical manipulations, integral expressions for the rate constants for the formation of different products are derived. The geometries of the reactant, intermediates, transition states, and products of the reaction are optimized at the MP2(full)/6-311++G(2d,2p) level of theory. More accurate energies are evaluated by single-point energy calculations at the CBS-Q, G4, and CCSD(T,full)/augh-cc-pVTZ+2df levels of theory. In order to account correctly for vibrational anharmonicities and tunneling effects, microcanonical rate constants for various channels are computed by using semiclassical transition state theory. It is found that the isomerization of CHCOCH to the enol form CHC(CH)OH plays an important role in the unimolecular decomposition reaction of CHCOCH. The possible products originating from unimolecular decomposition of CHCOCH and CHC(CH)OH are investigated. It is revealed from present computed rate coefficients that the dominant product channel is the formation of CHC(CH)OH at low temperatures and high pressures due to the low barrier height for the isomerization process CHCOCH → CHC(CH)OH. However, at high temperatures and low pressures, the product channel CH + CHCO becomes dominant. Also, the roaming product channels CHCO + CH and CH + CO could be important at high temperatures.

In this work, the liquid–solid phase transition temperature of water confined between two graphene oxide (GO) sheets is investigated using molecular dynamics simulations.

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The potential energy profile of the reaction between methyl radicals with acetaldehyde is theoretically investigated at different levels of theory prior to calculating the bimolecular rate constants of this reaction by semiclassical transition state theory (SCTST) and one‐dimensional master equation (1DME) modeling. The stationary points on the potential energy surface of the reaction CH3 + CH3CHO are characterized at the levels MP2/6‐311 + g(2d,2p) and CCD/6‐311 + g(2d,2p). To obtain more satisfying energies, single‐point calculations are performed at CCSD(T)/augh‐cc‐pVTZ+2df. It is shown that the title reaction proceeds via either hydrogen abstraction channels or the addition of methyl radical to acetaldehyde, forming an isopropoxy radical. Then, SCTST and 1DME modeling are used to compare the rate constants of distinct reaction channels. The aldehyde hydrogen atom abstraction by methyl radical producing CH4 + CH3CO is dominant both thermodynamically and kinetically. The calculated SCTST rate constants can be expressed as a function of temperature with cm3molecule−1s−1 (200‐3000 K). Hydrogen/deuterium (H/D) isotopic effects on the kinetics are computed for some specific abstraction channels, showing that tunneling indeed plays a vital role in the hydrogen abstraction process. Pressure dependencies of the addition reaction are followed using master equation calculations, illustrating that the stabilization of the isopropoxy radical is dominant at higher pressures and lower temperatures. In contrast, as pressure decreases and temperature increases, the energized radical prefers decomposing to new bimolecular sets.