Thermal decomposition of COCl[sub 2]

Journal Article · Thu Jan 06 04:00:00 EST 1994 · Journal of Physical Chemistry; (United States)

DOI:https://doi.org/10.1021/j100052a035· OSTI ID:5257145

Lim, K P; Michael, J V ^[1]

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1. Argonne National Lab., IL (United States)

The thermal decomposition of COCl[sub 2] has been studied in incident shock waves at three different loading pressures and varying [COCl[sub 2]][sub 0]. The kinetics experiments were performed at temperatures between 1400 and 2000 K by monitoring the product Cl atoms using the atomic resonance absorption spectrometric (ARAS) technique. Two decomposition pathways for COCl[sub 2] are possible: (1) COCl[sub 2] (+M) [yields] COCl + Cl (+M) and (2) COCl[sub 2] (+M) [yields] CO + Cl[sub 2] (+M). The branching ratios were observed to be 90[sub .5]% and 9[sub .5]%, respectively. Second-order analysis for the sum of (1) and (2) gave the rate expression k[sub d]/[Kr] = (8.0 [+-] 3.8) x 10[sup [minus]8] exp(-30549 [+-] 766 K/T) cm[sup 3] molecule[sup [minus]1] s[sup [minus]1], with an error of [+-] 35% at the one standard deviation level. This expression compares favorably to results from the decompositions of CH[sub 3]Cl, CH[sub 2]Cl[sub 2], and CCl[sub 4] and provides evidence to suggest that the [Delta]H[sup [circ]][sub 10] is in the range 70-80 kcal mol[sup [minus]1]. Theoretical analysis has also been applied to reaction 1 using Troe's semiempirical methods. The best overall fit is obtained with [Delta]H[sup [circ]][sub 10] = 74.5 [+-] 1.0 kcal mol[sup [minus]1] and [Delta]E[sub down] = 1714 cm[sup [minus]1]. This [Delta]H[sup [circ]][sub 10] implies [Delta][sub f]H[sup [circ]](0 K) = -6.3 [+-] 1.0 kcal mol[sup -1] for COCl. Similar theoretical analysis for reaction 2 suggests a barrier height of 81.35 kcal mol[sup [minus]]. 31 refs., 4 figs., 3 tabs.

• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 5257145
• Journal Information: Journal of Physical Chemistry; (United States), Journal Name: Journal of Physical Chemistry; (United States) Vol. 98:1; ISSN JPCHAX; ISSN 0022-3654
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
400800 -- Combustion
Pyrolysis
& High-Temperature Chemistry
ABSORPTION
ABSORPTION SPECTRA
ATOMS
CARBONIC ACID DERIVATIVES
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
CHLORINE
DECOMPOSITION
ELEMENTS
HALOGENS
KINETICS
MATHEMATICAL MODELS
NONMETALS
ORGANIC CHLORINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
PHOSGENE
PRESSURE DEPENDENCE
PYROLYSIS
REACTION KINETICS
RESONANCE ABSORPTION
SHOCK WAVES
SORPTION
SPECTRA
TEMPERATURE DEPENDENCE
THERMOCHEMICAL PROCESSES
THERMODYNAMICS