HOMOGENEOUS CATALYTIC SYNTHESIS OF FORMALDEHYDE USING THE TUNGSTEN CARBONYL COMPLEX [(CO)5WCL]- IN THE PRESENCE OF SODIUM METHOXIDE uri icon

abstract

  • Formaldehyde can be synthesized (Turnover number=10) from sodium methoxide and carbon dioxide using the anionic tungsten carbonyl complex [(CO)5WCl]- as catalyst precursor and a molar ratio NaOMe/W lower than 8 at 125C, 400 psi of CO2 for a 24-h period. The most probable mechanism involves the generation of the [(CO)5WOCH3]- species by the reaction of [(CO)5WCl]- with NaOMe. The methoxide complex can undergo -hydrogen abstraction to yield formaldehyde and the terminal hydride [(CO)5WH]-, which in turn, decomposes under reaction conditions to provide the bridging hydride [(-H)W2(CO)10]-. Carbon dioxide insertion into the complex [(CO)5WH]-, followed by reaction of NaOMe regenerates the alkoxide compound [(CO)5WOCH3]- and sodium formate. A kinetic study of the reaction of [(CO)5WCl]- with NaOMe suggests that the mechanism involves nucleophilic attack of the base on the metal center, and proceeds by two different pathways depending on the molar ratio base/metal. For a ratio NaOMe/W < 8 the -hydrogen reaction takes place with the formation of [(-H)W2(CO)10]- and formaldehyde. For higher base/metal ratio (>8) the formation of metal cluster is observed. 1994.

published proceedings

  • JOURNAL OF MOLECULAR CATALYSIS

author list (cited authors)

  • OVALLES, C., FERNANDEZ, C., & DARENSBOURG, D. J.

citation count

  • 2

complete list of authors

  • Ovalles, Cesar||Fernández, Carolina||Darensbourg, Donald J

publication date

  • October 1994