Reactions of sulfur atoms. XV. Absolute rate parameters for the S(/sup 3/P/sub 2/ /sub 1/ /sub 0/) + alkyne reactions
Using flash photolysis with vacuum uv kinetic absorption spectroscopy, absolute rate constants and Arrhenius parameters have been measured for the addition of ground state S(/sup 3/P/sub 2/,/sub 1/,/sub 0/) atoms to alkynes. The decay of sulfur atoms in COS, alkyne, and CO/sub 2/-diluent mixtures is first order in sulfur atom concentration and the first-order decay rate constants are proportional to the alkyne concentration. The following rate constants were determined at room temperature: k(C/sub 2/H/sub 2/) = k(C/sub 2/D/sub 2/) + (2.3 +- 0.4) x 10/sup 8/; k(CHCCH/sub 3/) = (4.8 +- 0.2) x 10/sup 9/; k(CHCC/sub 2/H/sub 5/) = (3.3 +- 0.2) x 10/sup 9/; k(CH/sub 3/CCCH/sub 3/) = 1.6 +- 0.2) x 10/sup 10/; k(CH/sub 3/CCC/sub 2/C/sub 5/) = 1.8 +- 0.3) x 10/sup 10/; and k(CF/sub 3/CCCF/sub 3/) = (2.1 +- 0.4) x 10/sup 8/ L mol/sup -1/ s/sup -1/. The Arrhenius parameters determined are k(C/sub 2/H/sub 2/) = (3.4 +- 1.9) x 10/sup 10/ exp((-3000 +- 400)/RT) L mol/sup -1/ s/sup -1/ and k(CHCCH/sub 3/) = (2.0 +- 1.2) x 10/sup 10/ exp((-900 +- 200)/RT) L mol/sup -1/s/sup -1/ where error limits represent standard deviations. The rate parameters are compared to those obtained for the addition of other electrophilic reagents to alkynes and the results discussed in terms of structural and kinetic factors. Theoretical treatment of the secondary H/D isotope effect in the acetylene reaction satisfactorily reproduces the experimental value. 5 tables, 4 figures, 59 references.
- Research Organization:
- Univ. of Alberta, Can.
- OSTI ID:
- 6660932
- Journal Information:
- J. Am. Chem. Soc.; (United States), Vol. 100:13
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ACETYLENE
CHEMICAL REACTIONS
ALKYNES
DEUTERIUM
ISOTOPE EFFECTS
ORGANIC FLUORINE COMPOUNDS
PROPYNE
SULFUR
ARRHENIUS EQUATION
ATOMS
CARBON DIOXIDE
CARBON OXYSULFIDE
CHEMICAL REACTION KINETICS
DEUTERIUM COMPOUNDS
PHOTOLYSIS
CARBON COMPOUNDS
CARBON OXIDES
CHALCOGENIDES
DECOMPOSITION
ELEMENTS
HYDROCARBONS
HYDROGEN COMPOUNDS
HYDROGEN ISOTOPES
ISOTOPES
KINETICS
LIGHT NUCLEI
NONMETALS
NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
REACTION KINETICS
STABLE ISOTOPES
SULFUR COMPOUNDS
400302* - Organic Chemistry- Isotope Effects- (-1987)