Kinetics Database Logo

Kinetics Database Resources

Simple Reaction Search

Search Reaction Database

Search Bibliographic Database

Set Unit Preferences


Rate Our Products and Services


Other Databases

NIST Standard Reference Data Program

NIST Chemistry Web Book

NDRL-NIST Solution Kinetics Database

NIST Computational Chemistry Comparison and Benchmark Database

The NIST Reference on Constants, Units, and Uncertainty


Administrative Links

NIST home page

MML home page

Chemical Sciences Division

  NIST Logo Home
©NIST, 2013
Accessibility information
Author(s):   McKee, K.; Blitz, M.A.; Hughes, K.J.; Pilling, M.J.; Qian, H.-B.; Taylor, A.; Seakins, P.W.
Title:   H Atom Branching Ratios from the Reactions of CH with C2H2, C2H4, C2H6, and neo-C5H12 at Room Temperature and 25 Torr
Journal:   J. Phys. Chem. A
Volume:   107
Page(s):   5710 - 5716
Year:   2003
Reference type:   Journal article
Squib:   2003MCK/BLI5710-5716

Reaction:   C2H2 + ·CH → Products +
Reaction order:   2
Reference reaction:   CH4 + ·CH → Products +
Reference reaction order:   2
Temperature:   295 K
Pressure:  3.33E-2 bar
Rate expression:   1.05±9.0x10-2
Bath gas:   He
Category:  Experiment
Data type:   Relative rate value measured
Pressure dependence:   None reported
Experimental procedure:   Static or low flow - Data taken vs time
Excitation technique:   Flash photolysis (laser or conventional)
Time resolution:   In real time
Analytical technique:   Laser induced fluorescence
Comments:   The authors have measured branching ratios for H atom production from the reaction of ground state CH with C2H2, C2H4, C2H6, and neo-C5H12 relative to that from the CH + CH4 reaction. The latter reaction was assumed to proceed via insertion followed by decomposition of an excited ethyl radical intermediate:
CH + CH4 = C2H5* = C2H4 + H
with 100% yield of H atoms. The reactions were studied at 295 K and pressures of 25 torr He using a slow-flow laser flash photolysis apparatus. H atom products were detected via Lyman R laser-induced fluorescence at 121.56 nm.

Mechanistic discussion is provided for all reactions. The reactions are characterized by fast barrierless CH insertions followed by decomposition of the hot intermediate.

View full bibliographic record.