KINETICS OF OXIRANE FORMATION IN THE REACTION OF NITRATE RADICALS WITH TETRAMETHYLETHYLENE

The kinetics of oxirane formation in the reaction of nitrate radicals with tetramethylethylene was investigated in a flow system at room temperature. Total pressure ranged from 5 to 1000 mbar. Using inert gas (He, N2) tetramethyloxirane only was detected as reaction product. In the case of synthetic air acetone also is formed in dependence of the system pressure. With increasing pressure the oxirane yield decreases and the acetone yield increases. Under tropospheric conditions 20% tetramethyloxirane was found. It is concluded that the oxirane observed results from the excited adduct formed in the electrophilic addition of the nitrate radical to the double bond. In the absence of O2 the quenched adduct radical formes oxirane in a thermal reaction also.