Mass and microwave spectroscopic studies of pyrolysates and pyrolysis mechanism of 1,1,2-trichloronitrosoethane

The pyrolysates of 1,1,2-trichloronitrosoethane (CH2Cl-CCl2-NO) have been i nvestigated by pyrolysis-mass spectrometry and microwave spectroscopy (Py-M S/MW). The five pyrolysates were identified to be 1,1-dichloroethene 1, nit rosyl chloride 2, chloroacetylene 3, formaldehyde 6 and cyanogen chloride 7 by microwave spectroscopy. The generation of 3 was verified by the direct reaction of 1 with NOX and Cl* radicals inside a Stark cell. Two radicals w ere generated by pyrolysis of 2. The observed ionic peaks m/z at 91 and 93 (C2H2ClNO) having the relative intensity of 3:1 were tentatively assigned t o 1-chloronitrosoethene (4 or 4') produced by elimination of Cl-2 of the pr ecursor. Two pyrolysis mechanisms of 1,1,2-trichloronitrosoethane were eluc idated by judging from these pyrolysates identified. One is that 1 is gener ated by elimination of 2, and 3 is furthermore produced by reaction of 1 wi th NO and Cl radicals. The other is that 4 may be generated by elimination of Cl-2 of the precursor and 6 and 7 may be produced by cleavage of four-me mbered ring molecule 5 produced by intramolecular cyclization of 4. (C) 200 0 Elsevier Science B.V. All rights reserved.