Single Pulse Shock Tube Studies on the Decomposition of CH₃Cl in the Presence of H₂

The mixtures of CH₃Cl and H₂ diluted in argon are shocked in a single pulse shock tube and the kinetics of the decomposition of CH₃Cl is studied at the temperature range 1050K＜ T＜ 1170 K,pressure range 0.5 MPa ＜P＜1 MPa.To interpret the experimental results,a chain reaction scheme is proposed and the following conclusions are leaded.The branching ratio of the reactions \mathrmH \cdot+\mathrmCH_3 \mathrmCl \xrightarrowk_3 \mathrmHCl+\mathrmCH_3 \cdot and \mathrmH \cdot+\mathrmCH_3 \mathrmCl \xrightarrowk_3^\prime \mathrmH_2+\mathrmCH_2 \mathrmCl \cdot is determined as k₃/k_3’=2.8,With the rate constant.k₃=9.7×10¹²exp（-4860/T）cm³mol^-1s^-1.The initiation reaction \mathrmCH_3 \mathrmCl \xrightarrowk_1 \mathrmCH_3 \cdot+\mathrmCl \cdot.is in the fall off region,near the high pressure limit,and k₁=1.0 × 10¹⁵exp （-41100/T）s^-1,P=1 MPa and k₁=6.6 × 10¹⁴exp （-40700/T）s^-1,P=0.5 MPa are determined.The mechanism of the production of C₂H₄ is revealed as reaction of CH₂Cl·+\mathrmH \cdot \xrightarrowk_5 \mathrmCH_2:+\mathrmHCl followed by \mathrmCH_2:+\mathrmCH_3 \mathrmCl \xrightarrow\text Fast \mathrmC_2 \mathrmH_4+\mathrmHCl,with the rate constant k₅=8.2×10¹⁵ T^0.63exp （-254/T）cm³mol^-1s^-1.