An Experimental and Kinetic
Modeling Study of the Reaction of
CHF<sub>3</sub> with Methane
Hai Yu
Eric M. Kennedy
John C. Mackie
Bogdan Z. Dlugogorski
10.1021/es0604212.s001
https://acs.figshare.com/articles/journal_contribution/An_Experimental_and_Kinetic_Modeling_Study_of_the_Reaction_of_CHF_sub_3_sub_with_Methane/3059062
The gas-phase reaction of CHF<sub>3</sub> with CH<sub>4</sub> has been
studied experimentally and computationally. The motivation
behind the study is that reaction of CHF<sub>3</sub> with CH<sub>4</sub>
provides a possible route for synthesis of CH<sub>2</sub>CF<sub>2</sub> (C<sub>2</sub>H<sub>2</sub>F<sub>2</sub>).
Experiments are carried out in a plug flow, isothermal
α-alumina reactor at atmospheric pressure over the
temperature range of 973−1173 K. To assist in understanding
the reaction mechanism and the role of the reactor
material involved in the reaction of CHF<sub>3</sub> with CH<sub>4</sub>, the
reaction of CHF<sub>3</sub> with CH<sub>4</sub>, pyrolysis of CH<sub>4</sub>, and pyrolysis
of CHClF<sub>2</sub> have been studied in the presence of α-alumina
or α-AlF<sub>3</sub> particles under various conditions. Under all
conditions studied for the reaction of CHF<sub>3</sub> and CH<sub>4</sub>, the
major products are C<sub>2</sub>F<sub>4</sub>, C<sub>2</sub>H<sub>2</sub>F<sub>2</sub>, and HF. Minor products
include C<sub>2</sub>H<sub>2</sub>, C<sub>2</sub>H<sub>4</sub>, C<sub>2</sub>H<sub>3</sub>F, C<sub>2</sub>HF<sub>3</sub>, C<sub>3</sub>F<sub>6</sub>, CO<sub>2</sub>, and H<sub>2</sub>. C<sub>2</sub>H<sub>6</sub>,
CH<sub>2</sub>F<sub>2</sub>, and CHF<sub>2</sub>CHF<sub>2</sub> are detected in trace amounts.
The initial step is the gas-phase unimolecular decomposition
of CHF<sub>3</sub>, producing CF<sub>2</sub> and HF. It is proposed that CF<sub>2</sub>
decomposes on the surface of α-alumina, producing F
radicals that are responsible for the activation of CH<sub>4</sub>. A
reaction scheme developed on the basis of the existing NIST
HFC and GRI-Mech 3.0 mechanisms is used to model the
reaction of CHF<sub>3</sub> with CH<sub>4</sub>. Generally satisfactory agreement
between experimental and modeling results is obtained
on the conversion levels of CHF<sub>3</sub> and CH<sub>4</sub> and rates of formation
of major products. Using the software package AURORA,
the reaction pathways leading to the formation of major
products are elucidated.
2006-09-15 00:00:00
H 2. C 2H CH 2F
CHF 3
3F
software package AURORA
CH 4.
2HF
C 2F C 2H
CH 4
HFC
Kinetic Modeling Study
CO
C 2H Experiments
2CHF
NIST
CF 2