Reaction of aromatic peroxyl radicals with alkynes: A mass spectrometric and computational study using the distonic radical ion approach

Abstract

The reaction of the aromatic distonic peroxyl radical cations N-methyl pyridinium-4-peroxyl (PyrOO.+) and 4-(N,N,N-trimethyl ammonium)-phenyl peroxyl (AnOO.+), with symmetrical dialkyl alkynes 10 a-c was studied in the gas phase by mass spectrometry. PyrOO.+ and AnOO.+ were produced through reaction of the respective distonic aryl radical cations Pyr.+ and An.+ with oxygen, O 2. For the reaction of Pyr.+ with O2 an absolute rate coefficient of k1=7.1×10-12 cm 3 molecule-1 s-1 and a collision efficiency of 1.2 % was determined at 298 K. The strongly electrophilic PyrOO.+ reacts with 3-hexyne and 4-octyne with absolute rate coefficients of k hexyne=1.5×10-10 cm3 molecule -1 s-1 and koctyne=2.8..