NIST Chemical Kinetics Database

Author(s):   Aranda, A.; Diaz de Mera, Y.; Rodriguez, D.; Rodriguez, A.; Cabanas, B.; Martinez, E.
Title:   Gas-phase reaction of chlorine atoms with acrylonitrile. Temperature and pressure dependence
Journal:   Chem. Phys. Lett.
Volume:   377
Page(s):   571 - 576
Year:   2003
Reference type:   Journal article
Squib:   2003ARA/DIA571-576

Reaction:   CH₂CHCN + Cl → ClCH₂CH(·)CN
Reaction order:   2
Temperature:   298 K
Pressure:  3.33E-3 bar
Rate expression:   8.8x10^-12 [±9.0x10^-13 cm³/molecule s]
Bath gas:   He
Category: Experiment
Data type:   Absolute value measured directly
Pressure dependence:   Rate constant is pressure dependent
Experimental procedure:   Flow tube - Data taken vs distance
Excitation technique:   Discharge
Time resolution:   In real time
Analytical technique:   Mass spectrometry
Comments:   The authors studied the kinetics and mechanism of the reaction of chlorine atoms with acrylonitrile (CH2CHCN) using the mass spectrometric discharge-flow method in the temperature range (260?33) K and at total pressures between 0.5 and 3 Torr of helium. Atomic chlorine was scavenged by Br2 via the reaction Cl +Br2 = BrCl + Br. Amounts of BrCl were detected in the presence and absence of acrylonitrile and used to back out the Cl decays and determine the rate constants. The pressure dependence of the reaction was determined between 0.5 and 3.0 torr of helium at 298 K.

In additional experiments in the absence of Br2 the authors were able to observe peaks attributable to the product ClCH2CH(·)CN. This evidence, together with the relatively low value of the pre-exponential factor, the negative temperature dependence observed, and the increase of k with pressure led the authors to suggest the reaction procedes via an association complex.

Listed uncertainties are 2 standard deviations plus an estimated 10% systematic uncertainty.

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