Propargyl from the reaction of singlet methylene with acetylene

Journal Article · Thu Feb 08 00:00:00 EST 1996 · Journal of Physical Chemistry

DOI:https://doi.org/10.1021/jp952147w· OSTI ID:219687

Adamson, J D; Morter, C L; DeSain, J D; Glass, G P; Curl, R F ^[1]

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1. Rice Univ., Houston, TX (United States)

The technique of infrared kinetic spectroscopy has been used to study the production of propargyl radical from the reaction of singlet methylene with acetylene. The rate constant for this product channel was determined to be (3.5{+-}0.7) x 10{sup -10} cm{sup 3} molecule{sup -1} s{sup -1} at 295 K, measured relative to the known rate for {sup 1}CH{sub 2} with H{sub 2} or CH{sub 4}. Methylene was produced in the singlet state by excimer laser photolysis of ketene at 308 nm in the presence of acetylene and either H{sub 2} or CH{sub 4}. Reaction of {sup 1}CH{sub 2} with acetylene produces propargyl, and reaction of {sup 1}CH{sub 2} with either H{sub 2} or CH{sub 4} produces CH{sub 3}. The intensity of a propargyl infrared absorption line was compared with that of a methyl infrared absorption line, and the rate of formation of propargyl was determined from the ratio of these two intensities and the known rate of reaction of singlet methylene with H{sub 2} (or CH{sub 4}) to produce CH{sub 3}. The relative peak infrared absorption cross sections of methyl and propargyl were calibrated under the conditions of the experiment by photolyzing crotyl bromide at 193 nm to produce methyl and propargyl in equal concentrations. 22 refs., 2 figs., 2 tabs.

• OSTI ID: 219687
• Journal Information: Journal of Physical Chemistry, Journal Name: Journal of Physical Chemistry Journal Issue: 6 Vol. 100; ISSN JPCHAX; ISSN 0022-3654
• Country of Publication: United States
• Language: English

Related Subjects

40 CHEMISTRY
66 PHYSICS
ACETYLENE
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
ENERGY LEVELS
INFRARED SPECTRA
METHYLENE RADICALS
PHOTOCHEMICAL REACTIONS
PROPARGYL RADICALS
SYNTHESIS