Reduction of benzaldehyde by methoxide ion in aqueous methanol

Journal Article · Wed Jun 20 04:00:00 EDT 1979 · J. Am. Chem. Soc.; (United States)

DOI:https://doi.org/10.1021/ja00507a024· OSTI ID:6001788

Swain, C G; Powell, A L; Lynch, T J; Alpha, S R; Dunlap, R P

In contrast to previous studies of the Cannizzaro reaction using isotopically labeled reactants, the benzyl alcohol from reaction of 0.60 M benzaldehyde-..cap alpha..-d and 0.25 M NaOH in 74% CH/sub 3/OH to 26% H/sub 2/O solution at 100/sup 0/C includes a substantial percentage of benzyl-..cap alpha..-d/sub 1/ alcohol (21% after half consumption of hydroxide ion) rather than only benzyl-..cap alpha..-d/sub 2/ alcohol. Products from C/sub 6/H/sub 5/CHO in CH/sub 3/OH, CH/sub 3/OH solutions indicate that the side reactions responsible for hydrogen exchanges and adding to the yield of benzyl alcohol are (1) bimolecular hydride transfer to benzaldehyde from methoxide ion, (2) a nearly equal amount of crossed Cannizzaro reaction from the resulting formaldehyde, (3) a smaller amount of hydride transfer to benzaldehyde from the resulting sodium formate leading to sodium carbonate, and (4) a less frequent combination of two benzaldehydes plus methoxide ion leading to benzaldehyde dimethyl acetal. Decreasing the initial concentration of C/sub 6/H/sub 5/CHO to 5 x 10/sup -4/ M decreases the relative contributions of the three termolecular reactions and causes the bimolecular hydride transfer (1) to become the dominant reaction. Its k/sub CH/sub 3/O/sup -///k/sub CD/sub 3/O/sup -// isotope effect is 2.2 +- 0.2. 1 table.

• Research Organization: Massachusetts Inst. of Technology, Cambridge
• OSTI ID: 6001788
• Journal Information: J. Am. Chem. Soc.; (United States), Journal Name: J. Am. Chem. Soc.; (United States) Vol. 101:13; ISSN JACSA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400301* -- Organic Chemistry-- Chemical & Physicochemical Properties-- (-1987)
ALCOHOLS
ALDEHYDES
ALKALI METAL COMPOUNDS
ARYL RADICALS
BENZALDEHYDE
BENZYL RADICALS
CARBON COMPOUNDS
CARBONATES
CHEMICAL REACTIONS
DEUTERIUM
FORMALDEHYDE
HYDRIDES
HYDROGEN COMPOUNDS
HYDROGEN ISOTOPES
HYDROXIDES
HYDROXY COMPOUNDS
ISOTOPE EFFECTS
ISOTOPES
LIGHT NUCLEI
MEDIUM TEMPERATURE
METHANOL
NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
OXYGEN COMPOUNDS
RADICALS
REDUCTION
SODIUM CARBONATES
SODIUM COMPOUNDS
SODIUM HYDROXIDES
STABLE ISOTOPES
WATER