First Study of the Pyrolysis of a Halogenated Ester: Methyl Chloroacetate

The pyrolysis of a halogenated ester,
methyl chloroacetate (MC),
under dilute atmosphere and quasi-atmospheric pressure was studied
at temperatures from 473 to 1048 K using an alumina tubular reactor.
MC was chosen as a surrogate to model the thermal decomposition of
ethyl bromoacetate, a chemical warfare agent. A maximum MC conversion
of 99.8% was observed at a residence time of 2 s, a temperature of
1048 K, and an inlet mole fraction of 0.01. The following products
were quantified: CO, CO2, HCl, methane, ethylene, ethane,
propene, chloromethane, dichloromethane, vinyl chloride, chloroethane,
and dichloroethane. For the first time, a detailed kinetic model of
MC pyrolysis was developed and gave a good prediction of the global
reactivity and the formation of most of the major products. Flow rate
and sensitivity analyses were made to highlight the different pathways
of decomposition during the MC pyrolysis. In a first attempt to extrapolate
the results obtained with methyl chloroacetate to ethyl bromoacetate,
simulations were run with a modified version of the model developed
in this study taking into account the differences in bond dissociation
energies induced by the change of the chlorine atom by a bromine one.