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Analysis of the gas‐phase addition of water to formaldehyde: A semiempirical and ab initio study of bifunctional catalysis by H 2 O
Author(s) -
Ventura Oscar N.,
CoitiñO Elena L.,
Lledós Agustí,
Bertran Juan
Publication year - 1992
Publication title -
journal of computational chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.907
H-Index - 188
eISSN - 1096-987X
pISSN - 0192-8651
DOI - 10.1002/jcc.540130902
Subject(s) - mndo , ab initio , chemistry , bifunctional , computational chemistry , formaldehyde , catalysis , ab initio quantum chemistry methods , molecule , organic chemistry
Semiempirical AM1, MNDO‐PM3, and MNDO/M, as well as ab initio Hartree–Fock and Möller–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 Δ G 0,‡ (from 48 to 33 kcal/mol) when an ancillary water molecule is used as catalyst. AM1 and MNDO‐PM3 predict anticatalysis instead; Δ G 0,‡ for the termolecular addition is larger than the one for the bimolecular reaction. MNDO/M predicts a modest decrease, from 42 to 39 kcal/mol. 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 quatitatively) in disagreement with this conclusion. © 1992 by John Wiley & Sons, Inc.