Theoretical study of reactions between AlH(1?) and HF molecule

Abstract

ABSTRACT:Reaction mechanisms between AlH ⌺ and HF molecule are theoretically investigated. Ab initio calculations demonstrate that there are two parallel reaction channels: one is an addition reaction to give H AlF via the three-membered ring 2 Ž . transition state TS and the other is a dehydrogenation reaction to give AlF q H via the 2 four-membered ring TS. The addition reaction is thermodynamically favorable and the dehydrogenation reaction is kinetically favorable. Thermodynamics and Eyring transition Ž . state theory TST with the Wigner correction are also used to compute the thermodynamic functions, the equilibrium constants, A factors, and the rate constants of these reaction channels at 200᎐1000 K. From the thermodynamics and TST calculations, it is valuable to point out that consideration on the entropy and thermal enthalpy is quite important in the study of chemical reactions on the basis of ab initio method.

Theoretical study of reactions between MH (M=B, Al) and the H2S molecule

“…Recently, Davidson 18 and Ju 19 pointed out that it is unsuitable to judge the reactivity only by a quantum chemistry method. Our studies 16, 17 also pointed out that it is more important to investigate the effects of increased temperatures on a family of related parallel reactions. Therefore, further calculations of thermodynamic and kinetic properties with different experimental temperatures have been performed.…”

“…In order to investigate the effect of temperature on the reaction paths which exist possibly in the systems of MH (M=B, Al) and H 2 S, general statistical thermodynamics (GST) 27 was used to evaluate the thermodynamic functions and equilibrium constants, and the Eyring transition state theory (TST) 28 with the Wigner correction is also used to calculate the rate constants ( k ( T )) which is described in Ref. 17.…”

“…Such well‐known examples as CH, BH, SiH, and AlH have been the subject of active investigation both experimentally and theoretically 1–17. Among these monovalent hydrides, BH and AlH, as two homologous compounds, are particularly interesting because their singlet states have one σ‐electron pair and two empty p‐orbitals, respectively, so they are both nuclephile in the direction of the σ‐orbital and electrophile in the direction of the empty p‐orbital, which result in their complex reactivities in interaction with small polar molecules such as HCl, HF, H 2 O 7, 15–17. These reactions have common characters—there are two parallel reaction channels: one is an addition reaction via the three‐membered ring transition state and the other is a dehydrogenation reaction via the four‐membered ring transition state.…”

“…These reactions have common characters—there are two parallel reaction channels: one is an addition reaction via the three‐membered ring transition state and the other is a dehydrogenation reaction via the four‐membered ring transition state. Reaction mechanisms of AlH( 1 Σ) with X–H (X=F, Cl, OH) have been studied in detail 16, 17, whereas there has not been a complete study of the reaction mechanism of BH( 1 Σ), and little is also known about the differences of the nuclephilic and electrophilic abilities between BH( 1 Σ) and AlH( 1 Σ).…”

Studies on the thermodynamic and kinetic properties of the insertion reactions for 1 XAl (X = H, Na, F, Cl, SH) with polar molecule hydrogen chloride at 200–1000 K

“…Particular attention has been focused on the aluminum species due to their importance in the area of chemical catalysis and elementary chemistry. A number of experimental and theoretical studies on the spectroscopy, kinetic and energetic of aluminum-containing radicals have been reported [6][7][8][9][10]. For the kinetic point of view, the reactions of aluminum species play a central role in many high-temperature environments and combustion chemistry [11].…”