Isotope Effects in the Acid-catalyzed Isomerization of Cinnamic Acids

Journal Article · Tue May 01 04:00:00 EDT 1962 · Journal of the American Chemical Society

DOI:https://doi.org/10.1021/ja00868a030· OSTI ID:4834444

Noyce, Donald S.; Avarbock, Harvey S.; Reed, Wilmer L.

The solvent isotope effect upon the rate of isomerization of cis- cinnamic acids is substantial. At 25 deg in 47% sulfuric acid k/sub H/sub 2/O/K/ sub D/sub 2/ O/ is 6 for the isomerization of cis-p-metho xycinnamic acid. The Gross-Butler equation is not followed when the deuterium content of the solvent is varied. A detailed mechanism for the isomerization of cis-cinnamic acids is presented, a mechanism involving direct proton addition to give a solvated carbonium ion. Since the reaction rate parallels H/sub o/ with unit slope, the acidity function is not a useful criterion for rate-determining proton transfers.

• Research Organization: Univ. of California, Berkeley
• Sponsoring Organization: USDOE
• NSA Number: NSA-16-017655
• OSTI ID: 4834444
• Journal Information: Journal of the American Chemical Society, Journal Name: Journal of the American Chemical Society Journal Issue: 9 Vol. 84; ISSN 0002-7863
• Publisher: American Chemical Society (ACS)
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

CATALYSIS
CHEMISTRY
DEUTERIUM
DEUTERIUM COMPOUNDS
ISOTOPE EFFECTS
PROTONS
REACTION KINETICS
SOLVENTS
SULFURIC ACID