REACTION PATHWAYS FOR GAS-PHASE HYDROLYSIS OF FORMYL COMPOUNDS HXCO (X = H, F, AND CL)

Formation and decomposition of the adduct species CHX(OH)2, where X = H, F, and Cl, have been studied by means of ab initio molecular orbita l theory. Equilibrium geometries and transition structures have been f ully optimized with 6-31G and 6-311G** basis sets at the Hartree-Fock and second-order Moller-Plesset perturbation levels of theory. Heats of reaction and barrier heights have been computed with Moller-Plesset theory up to full fourth order using the 6-311++G* basis. Addition o f H2O to HXCO yields CHX(OH)2 which then decomposes preferentially by 1,2-elimination of HX to give formic acid as a product. Other higher e nergy paths, including 1,2-elimination of H-2 and the involvement of c arbene species, are of negligible significance.