Kinetics and thermochemistry of C sub 2 H sub 3 and CH sub 2 CCl radicals: Study of the C sub 2 H sub 3 + HCl = C sub 2 H sub 4 + Cl and CH sub 2 CCl + HCl = C sub 2 H sub 3 Cl + Cl reactions

Journal Article · Thu Jun 29 00:00:00 EDT 1989 · Journal of Physical Chemistry; (USA)

DOI:https://doi.org/10.1021/j100350a032· OSTI ID:7197264

Russell, J J; Senkan, S M ^[1]; Seetula, J A; Gutman, D ^[2]

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1. Illinois Institute of Technology, Chicago (USA)
2. Catholic Univ. of America, Washington, DC (USA)

The kinetics of the reactions of C{sub 2}H{sub 3} and CH{sub 2}CCl radicals with HCl have been studied in a tubular flow reactor coupled to a photoionization mass spectrometer in the temperature range 298-495 K. Each radical was produced by the pulsed homogeneous photolysis of a suitable precursor using an excimer laser. Radical decay and product growth profiles were monitored in time-resolved experiments. The Arrhenius rate expression obtained from the measured C{sub 2}H{sub 3} + HCl rate constants is 6.6 ({plus minus}1.0) {times} 10{sup {minus}13} exp(670 ({plus minus}230) cal mol{sup {minus}1}/RT) cm{sup 3} molecule{sup {minus}1} s{sup {minus}1}. The heat of formation (67.1 ({plus minus}0.6) kcal mol{sup {minus}1}) and entropy (55.9 ({plus minus}2.6) cal mol{sup {minus}1} K{sup {minus}1}) of C{sub 2}H{sub 3} were determined from this kinetic information on the C{sub 2}H{sub 3} + HCl reaction together with recently measured rate constants for the Cl + C{sub 2}H{sub 4} reaction. A Third Law treatment of the same data using a calculated entropy yields essentially the same heat of formation (66.9 ({plus minus} 0.3) kcal mol{sup {minus}1}) but with reduced uncertainty limits. The rate constant for the CH{sub 2}CCl + HCl reaction was found to be temperature independent, having an average value over the temperature range covered of 2.2 ({plus minus}0.3) {times} 10{sup {minus}13} cm{sup 3} molecule {sup {minus}1} s{sup {minus}1}/. This result was used to obtain a lower limit for the CH{sub 2}CCl heat of formation of 60 ({plus minus}0.3) kcal mol{sup {minus}1}. The reduced reactivity caused by chlorine substitution at the radical site is briefly discussed.

• OSTI ID: 7197264
• Journal Information: Journal of Physical Chemistry; (USA), Journal Name: Journal of Physical Chemistry; (USA) Vol. 93:13; ISSN 0022-3654; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400000* -- Chemistry
400201 -- Chemical & Physicochemical Properties
400800 -- Combustion
Pyrolysis
& High-Temperature Chemistry
ALKANES
ALKYL RADICALS
CHEMICAL REACTION KINETICS
CHLORINE
DATA
ELEMENTS
ETHANE
EXPERIMENTAL DATA
HALOGENS
HYDROCARBONS
INFORMATION
KINETICS
MASS SPECTROSCOPY
MEASURING INSTRUMENTS
MEASURING METHODS
MEDIUM TEMPERATURE
NONMETALS
NUMERICAL DATA
ORGANIC COMPOUNDS
RADICALS
REACTION KINETICS
SPECTROSCOPY
THERMOCHEMICAL PROCESSES
VINYL RADICALS