A Systematic Investigation into the Mechanism of the Reaction Between CF₃ Radicals and CO/O₂

Abstract

A complete study of the reaction of CF(3) radicals in the presence of CO and O(2) was carried out by using isotopically labeled reagents to form, selectively, all the possible isotopomers of the intermediate trioxide, CF(3)OC(O)OOOC(O)OCF(3), and of the stable peroxide, CF(3)OC(O)OOC(O)OCF(3). Analyses were carried out by means of FTIR spectroscopy in combination with ab initio calculations. At temperatures close to 0 degrees C, the acyloxy radicals formed were shown to exist long enough to yield a statistical mixture of isotopomers. In previous reports their lifetime was considered to be too short.

Electrochemical Trifluoromethoxylation of (Hetero)aromatics with a Trifluoromethyl Source and Oxygen

“…We envisioned that CF 3 radical might be captured by O 2 in the diffuse layer to afford CF 3 OO radical, [30] thus precluding the competitive trifluoromethylation reaction. Subsequently, the cathodic reduction of the reactive CF 3 OO radical would deliver CF 3 O radical [31] . Finally, the newly generated CF 3 O radical could diffuse into the bulk solution to react with aromatics for the formation of the desired trifluoromethoxylated product.…”

“…The radical anion int‐2 collapses to release CF 3 radical and sulfinate ion [35] . Subsequently, CF 3 radical combines with O 2 to afford CF 3 OO radical, [30] which could be reduced at cathode for the formation of the key CF 3 O radical intermediate [31] . Addition of CF 3 O radical to (hetero)aromatics gives the dearomatized intermediate int‐3 .…”

Thermal decomposition of trifluoromethoxycarbonyl peroxy nitrate, CF3OC(O)O2NO2

“…The reaction leading to the unimolecular decarboxylation of CF 3 OCOO: has been analyzed as part of a thorough study of the catalytic oxidation of CO to CO 2 mediated by CF 3 O radicals at 298 K 15. Measurements of the rate constant at different temperatures have not been reported.…”

Bis(trifluoromethyl)dicarbonate, CF3OC(O)OC(O)OCF3

“…However, it was in the late nineties when the next related compound, bis(perfluoromethyl)peroxydicarbonate, CF 3 OC(O)OOC(O)OCF 3 [4] was described. This thermally stable peroxide was synthesized in preparative scale and characterized some years later [7][8][9]. One of the by-products in its synthesis, bis(perfluoromethyl)trioxydicarbonate, CF 3 OC(O)OOOC(O)OCF 3 , the first open chain carbonyl containing trioxide has been isolated recently [7,10].…”

“…Though at lower temperatures the lifetime is strongly increased [9], the temperature chosen in our experiments still allows an efficient formation of CF 3 O radicals and due to the large excess of CO in the gas mixture (approximately 1:60 with respect to the trioxide) reaction (6):…”