Ambient temperature removal rate constants for singlet méthylène with some nitrogen and sulphur compounds

The technique of laser flash photolysis/laser absorption has been used to obtain absolute removal rate constants for singlet méthylène, ¹CH₂ (๠AI), with some nitrogen and sulphur compounds at ambient temperature (298±2 K). A measurement of the removal rate constant for ¹CH₂ with NH₃ yielded a value of (3.33±0.19)×^-10 cm³ molecule^-1 s^-1, in good agreement with the only previously reported measurement. Removal rate constants for the reactants CH₃NO₂, CH₃CH₂NO₂, CH₃CH₂CH₂NO₂, CH₃CN, CH₃CH₂CH₂CN, CH₂=CHCN, H₂S, CH₃CH₂SH, CH₃SCH₃, CH₃SSCH₃, and CH3COSH were measured for the first time and found to be (3.23±0.28), (3.46±0.69), (3.55±1.28), (4.51±0.21), (3.64±0.41), (4.10±0.26), (3.87±0.22), (4.77±0.25), (4.53±0.23), (5.37±0.53), and (4.59±0.32)×10^-10 cm³ molecule^-1 s^-1, respectively. The calculated removal efficiencies (removal rate constant relative to the Lennard-Jones collision rate constant) are indicative of reaction being the dominant process leading to loss of ¹CH₂. Comparisons are drawn between the reactivities of the nitrogen and sulphur functional groups and their hydrocarbon analogues, and between the sulphur compounds and their isoelectronic oxygen analogues.