Mechanism of the Cannizzaro reaction
Journal Article
·
· J. Am. Chem. Soc.; (United States)
An ultimate technique for disqualifying compounds suspected of being intermediates is illustrated by the use of isotope dilution to prove that benzyl benzoate is not an intermediate in the Cannizzaro reaction of 0.5 M benzaldehyde-p-t (tritium labeled) with 0.25 M sodium hydroxide in 74% methanol to 26% water at 100/sup 0/C. The adduct from hydroxide ion and two molecules of benzaldehyde that was thought to rearrange to benzyl benzoate could alternatively rearrange directly to the products, benzoate ion and benzyl alcohol. However, this mechanism also is disproved because methoxide ion acting instead of hydroxide ion should lead to zenzyl methyl ether, but less than 1% is found. Two other mechanisms involving a proton transfer concerted with the hydride transfer are disproved by the k/sub D/sub 2/O//k/sub H/sub 2/O/ isotope effect of 1.9. The rate-determining steps can be represented by two hydride transfer reactions to C/sub 6/H/sub 5/CHO, from the adduct from HO/sup -/ + C/sub 6/H/sub 5/CHO and from the adduct from CH/sub 3/O/sup -/ + C/sub 6/H/sub 5/CHO, or, equivalently, by two termolecular reactions, HO/sup -/ + 2C/sub 6/H/sub 5/CHO and CH/sub 3/O/sup -/ + 2C/sub 6/H/sub 5/CHO. 8 tables.
- Research Organization:
- Massachusetts Inst. of Technology, Cambridge
- OSTI ID:
- 6195518
- 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
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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
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CHEMICAL REACTION KINETICS
ETHERS
HYDRIDES
HYDROGEN COMPOUNDS
HYDROGEN ISOTOPES
HYDROXIDES
HYDROXY COMPOUNDS
ISOTOPE APPLICATIONS
ISOTOPE DILUTION
ISOTOPES
KINETICS
LIGHT NUCLEI
METHANOL
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
OXYGEN COMPOUNDS
RADICALS
RADIOISOTOPES
REACTION KINETICS
SODIUM COMPOUNDS
SODIUM HYDROXIDES
SYNTHESIS
TRACER TECHNIQUES
TRITIUM
WATER
YEARS LIVING RADIOISOTOPES
400301* -- Organic Chemistry-- Chemical & Physicochemical Properties-- (-1987)
ALCOHOLS
ALDEHYDES
ALKALI METAL COMPOUNDS
ARYL RADICALS
BENZALDEHYDE
BENZYL RADICALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CHEMICAL REACTION KINETICS
ETHERS
HYDRIDES
HYDROGEN COMPOUNDS
HYDROGEN ISOTOPES
HYDROXIDES
HYDROXY COMPOUNDS
ISOTOPE APPLICATIONS
ISOTOPE DILUTION
ISOTOPES
KINETICS
LIGHT NUCLEI
METHANOL
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
OXYGEN COMPOUNDS
RADICALS
RADIOISOTOPES
REACTION KINETICS
SODIUM COMPOUNDS
SODIUM HYDROXIDES
SYNTHESIS
TRACER TECHNIQUES
TRITIUM
WATER
YEARS LIVING RADIOISOTOPES