𝔖 Bobbio Scriptorium
✦   LIBER   ✦

Analysis of the gas-phase addition of water to formaldehyde: A semiempirical and ab initio study of bifunctional catalysis by H2O

✍ Scribed by Oscar N. Ventura; Elena L. CoitiñO; Agustí Lledós; Juan Bertran

Publisher
John Wiley and Sons
Year
1992
Tongue
English
Weight
849 KB
Volume
13
Category
Article
ISSN
0192-8651

No coin nor oath required. For personal study only.

✦ Synopsis

Semiempirical AM1, MNDO-PM3, and MNDO/M, as well as ab initio Hartree-Fock and Moller-Plesset calculations using the 4-31G, 6-31G(d,p), and 6-31 +G(d,p) basis sets have been done on the water-assisted addition of water to formaldehyde. Ab initio methods predict a reduction of 30% of the bimolecular AGO,* (from 48 to 33 kcalimol) when an ancillary water molecule is used as catalyst. AM1 and MNDO-PM3 predict anticatalysis instead; AGO,* for the termolecular addition is larger than the one for the bimolecular reaction. MNDOiM predicts a modest decrease, from 42 to 39 kcalimol. We conclude that, as predicted by the ab initio calculations, there is a bifunctional catalysis caused by the ancillary water. Two of the semiempirical methods are qualitatively (and all of them quantitatively) in disagreement with this conclusion.

📜 SIMILAR VOLUMES

Ab initio study of the gas-phase equilib
Ab initio study of the gas-phase equilibrium between (H2O)4 and (H2O)8
✍ A.M. Ferrari; E. Garrone; P. Ugliengo 📂 Article 📅 1993 🏛 Elsevier Science 🌐 English ⚖ 372 KB

Ab initio techniques inclusive of electron correlation (MP2) are used to study the gas-phase dimerization of water tetramers (T) into octamers (0), which is relevant to a model for the specific heat of liquid water. The T species has one basic structure, whereas three different conformations for the

An ab initio study of water clusters in
An ab initio study of water clusters in gas phase and bulk aqueous media: (H2O)n, n=1–12
✍ D. M. Upadhyay; M. K. Shukla; P. C. Mishra 📂 Article 📅 2000 🏛 John Wiley and Sons 🌐 English ⚖ 263 KB 👁 2 views

Geometries of several clusters of water molecules including single minimum energy structures of n-mers (n = 1-5), several hexamers and two structures of each of heptamer to decamer derived from hexamer cage and hexamer prism were optimized. One structural form of each of 11-mer and 12-mer were also

Gas-phase characterization of the neutra
Gas-phase characterization of the neutral and cationic Si2O2 molecules. A combined experimental and ab initio study
✍ Norman Goldberg; Muhammad Iraqi; Wolfram Koch; Helmut Schwarz 📂 Article 📅 1994 🏛 Elsevier Science 🌐 English ⚖ 508 KB

## AbSbCt Collision experiments are reported for the generation and characterization of the neutral and cationic SisO, molecule. In addition to the experimental character&ion of Si202, high-level ab initio calculations ( CCSD (T ) /PVTZ//MP2/6-3 11 G (df ) ) have been performed in order to support

Theoretical study of the gas-phase addit
Theoretical study of the gas-phase addition of HF and HCl to ethylene: Analysis of the catalytic action of dimeric halides
✍ M. I. Menéndez; D. Suárez; J. A. Sordo; T. L. Sordo 📂 Article 📅 1995 🏛 John Wiley and Sons 🌐 English ⚖ 648 KB

Ab initio MP2/6-31G\*\* calculations render the same mechanism for the gasphase addition of HF and HC1 to ethylene in contrast with previous HF/3-21G calculations. The leading interaction is in both cases the electrophilic attachment of the hydrogen atom in the hydrogen halide to a carbon atom in et