HCl yield and chemical kinetics study of the reaction of Cl atoms with CH3I at the 298 K temperature using the infra-red tunable diode laser absorption spectroscopy

• ArF pulsed excimer photolysis laser and IR tunable diode probe laser.
• The modelling of the reactions CH3 + CH3ICl and CH3I + CH3ICl.
• HCl yield is nonlinear decreasing with increasing the [CH3I].
• HCl yield is nonlinear decreasing with increasing the [CH3] radical.

Pulsed ArF excimer laser (193 nm) – CW infrared(IR) tunable diode laser Herriott type absorption spectroscopic technique has been made for the detection of product hydrochloric acid HCl. Absorption spectroscopic technique is used in the reaction chlorine atoms with methyl iodide (Cl + CH3I) to the study of kinetics on reaction Cl + CH3I and the yield of (HCl). The reaction of Cl + CH3I has been studied with the support of the reaction Cl + C4H10 (100% HCl) at temperature 298 K. In the reaction Cl + CH3I, the total pressure of He between 20 and 125 Torr at the constant concentration of [CH3I] 7.0 × 1014 molecule cm−3. In the present work, we estimated adduct formation is very important in the reaction Cl + CH3I and reversible processes as well and CH3I molecule photo-dissociated in the methyl [CH3] radical. The secondary chemistry has been studied as CH3 + CH3ICl = product, and CH3I + CH3ICl = product2. The system has been modeled theoretically for secondary chemistry in the present work. The calculated and experimentally HCl yield nearly 65% at the concentration 1.00 × 1014 molecule cm−3 of [CH3I] and 24% at the concentration 4.0 × 1015 molecule cm−3 of [CH3I], at constant concentration 4.85 × 1012 molecule cm−3 of [CH3], and at 7.3 × 1012 molecule cm−3 of [Cl]. The pressure dependent also studied product of HCl at the constant [CH3], [Cl] and [CH3I]. The experimental results are also very good matching with the modelling work at the reaction CH3 + CH3ICl = product (k = (2.75 ± 0.35) × 10−10 s−1) and CH3I + CH3ICl = product2 (k = 1.90 ± 0.15) × 10−12 s−1. The rate coefficients of the reaction CH3 + CH3ICl and CH3I + CH3ICl has been made in the present work. The experimental results has been studied by two method (1) phase locked and (2) burst mode.

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