Carbon acidity. 58. Hydrogen isotope exchange kinetics of propylene with lithium cyclohexylamide

Journal Article · Wed Oct 21 04:00:00 EDT 1981 · J. Am. Chem. Soc.; (United States)

DOI:https://doi.org/10.1021/ja00411a031· OSTI ID:5887306

Boerth, D W; Streitwieser, A Jr

Rates for hydrogen isotope exchange with lithium cyclohexylamide (LiCHA) in cyclohexylamine-N,N-d/sub 2/ (CHA-d/sub 2/) and cyclohexylamine (CHA) are compared for propene and toluene. Benzyl hydrogens in toluene were found to be 6.2 times more reactive than allyl hydrogens in propene. Experimental primary isotope effects are also reported for propene: k/sup D/-(exptl)/k/sup T/(exptl) = 2.9, k/sup H/(exptl)/k/sup T/(exptl) = 30, and k/sup H/(exptl)/k/sup D/(exptl) = 10.2. Derived internal return values show comparable values for propene and toluene. Analysis of polydeuteration rates shows that exchange is accompanied by complete equilibration of allyl positions. The high isotope effects and comparable acidities and internal return imply a transition state for propene which resembles that of toluene. An equilibrium pK/sub a/ on the CsCHA scale of approx. 43 is deduced for propene.

• Research Organization: Univ. of California, Berkeley
• OSTI ID: 5887306
• Journal Information: J. Am. Chem. Soc.; (United States), Journal Name: J. Am. Chem. Soc.; (United States) Vol. 103:21; ISSN JACSA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400203* -- Isotope Exchange & Isotope Separation-- (-1987)
400303 -- Organic Chemistry-- Isotope Exchange & Isotope Separation-- (-1987)
ALKENES
AMIDES
AROMATICS
CHEMICAL REACTIONS
COMPLEXES
DATA
DEUTERIUM
ELEMENTS
EXPERIMENTAL DATA
HYDROCARBONS
HYDROGEN
HYDROGEN ISOTOPES
INFORMATION
ISOTOPES
ISOTOPIC EXCHANGE
KINETICS
LIGHT NUCLEI
LITHIUM COMPLEXES
NONMETALS
NUCLEI
NUMERICAL DATA
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PROPYLENE
REACTION KINETICS
STABLE ISOTOPES
TOLUENE