67000-50-4Relevant articles and documents
Reactions of H3O+ and H2O+ with several fully halogenated bromomethanes
Thomas,Kennedy,Mayhew,Watts
, p. 8489 - 8495 (2007/10/03)
The bimolecular rate coefficients and ion products for the reactions of H3O+ and H2O+ with the bromine-containing molecules CF3Br, CF2Br2, CF2BrCl, CFBr3, CFBr2Cl, and CBrCl3 at 300 K are reported. With the exception of the reactions of H3O+ with CF3Br and CF2BrCl, the rate coefficients are near the collisional values (k ≈ 10-9 cm3 molecule-1 s-1). The most efficient exit pathway for the majority of the H3O+ reactions is the formation of a trihalomethyl cation, together with water and a hydrogen halide as the neutral products. In each case, more than one trihalomethyl cation can be formed. The branching ratios are largest for the products resulting from the breaking of a C-F bond. This is attributed to the high bond strength of HF relative to HCl and HBr. Similarly for CBrCl3, the major product cation is CCl2Br+. The H2O+ reactions are found to proceed predominantly via charge transfer. For the reaction of H2O+ with CF3Br there is clear evidence for intimate reaction pathways in which bonds are broken and formed.
Chemistry of CFn(1+) (n = 1-3) Ions with Halocarbons
Morris, Robert A.,Viggiano, A. A.,Doren, Jane M. Van,Paulson, John F.
, p. 2597 - 2603 (2007/10/02)
The gas-phase reactions of CF(1+), CF2(1+), and CF3(1+) with the halocarbons CF3Cl, CF3Br, CF3I, CF4, and C2F6 have been studied using a variable-temperature-selected ion flow tube (VT-SIFT) instrument at 300 and 496 K.The ion CF(1+) reacts rapidly with CF3X (X = Cl, Br, I) producing the ions CF2X(1+).In the reaction of CF(1+) with CF3Cl, CF3(1+) is also produced as a minor product.Curvature was observed in the pseudo-first-order kinetics plots for the reactions of CF(1+) with CF4 and C2F6.In both cases the curvature is attributed to the presence of two or more CF(1+) states (probably vibrational) of differing reactivities toward the perfluorocarbon of interest.This conclusion is supported by our observation of charge transfer from CF(1+) to NO, a reaction which is endothermic by 15 kJ/mol for the ground state of CF(1+).CF(1+) is unreactive with O2, N2, and Xe.The reactions of CF2(1+) with CF3X yield CF3(1+) and CF2X(1+) for X = Cl and Br; for X = I, CF2I(1+) and CF3I(1+) are produced.The overall reactions proceed at approximately the collision rate at 300 and 496 K, and the branching ratios are not strongly dependent on temperature.The reactions of CF2(1+) with CF4 and C2F6 produce CF3(1+) and C2F5(1+), respectively.The rate constants decrease significantly with increasing temperature.CF2(1+) reacts rapidly by charge transfer with NO.The reaction of CF2(1+) with O2, producing CF2O(1+), is inefficient.CF2(1+) is unreactive with N2.CF3(1+) reacts with CF3X (X = Cl, Br, I) at rates below the collision values, producing a single ionic product, CF2X(1+).While the rate constants for the reactions of CF3(1+) with CF3X increase in the series with increasing CF3X mass, the rate constants for reaction with each CF3X decrease sharply with increasing temperature.A mechanism is proposed in which the reaction proceeds on a double-well potential energy surface.No reaction was observed for the CF3(1+)/CF4 system.CF3(1+) appeared to react very slowly with C2F6 and NO, producing C2F5(1+) and NO(1+), respectively, but reactions with impurities in the neutral reagents cannot be ruled out as the source of these ions.CF3(1+) is unreactive with O2 and N2.
