Bis(trifluoroacetyl) Peroxide, CF₃C(O)OOC(O)CF₃

Abstract

Pure, highly explosive CF(3)C(O)OOC(O)CF(3) is prepared for the first time by low-temperature reaction between CF(3)C(O)Cl and Na(2)O(2). At room temperature CF(3)C(O)OOC(O)CF(3) is stable for days in the liquid or gaseous state. The melting point is -37.5 degrees C, and the boiling point is extrapolated to 44 degrees C from the vapor pressure curve log p = -1875/T + 8.92 (p/mbar, T/K). Above room temperature the first-order unimolecular decay into C(2)F(6) + CO(2) occurs with an activation energy of 129 kJ mol(-1). CF(3)C(O)OOC(O)CF(3) is a clean source for CF(3) radicals as demonstrated by matrix-isolation experiments. The pure compound is characterized by NMR, vibrational, and UV spectroscopy. The geometric structure is determined by gas electron diffraction and quantum chemical calculations (HF, B3PW91, B3LYP, and MP2 with 6-31G basis sets). The molecule possesses syn-syn conformation (both C=O bonds synperiplanar to the O-O bond) with O-O = 1.426(10) A and dihedral angle phi(C-O-O-C) = 86.5(32) degrees. The density functional calculations reproduce the experimental structure very well.

Fluorocarbon oxy and peroxy radicals

“…Quantum chemical calculations predict a strongly exothermic dissociation of CF 3 CO 2 into CF 3 and CO 2 (DH ¼ À136 kJ mol À1 ) and a very small activation barrier of 20.5 kJ mol À1 for this reaction [99]. This is in agreement with experimental observations, where any formation of CF 3 CO 2 by thermolysis or photolysis of CF 3 C(O)OOC(O)CF 3 failed and only products of the further decay of CF 3 CO 2 were found in the matrix isolated reaction products [61]: …”

Formation and dissociation kinetics of the FC(O)OOO(O)CF, FS(O2)OOO(O2)SF and FC(O)OOO(O2)SF trioxides: A theoretical study

“…In particular, for the fluorosulfate FS(O 2 )O radical, several experimental and theoretical kinetic investigations have been reported [13][14][15][16][17][18][19][20][21][22]. Interesting compounds could be generated by association reactions between these radicals [23][24][25]. In fact, the FC(O)OOO(O)CF is formed as a byproduct in the thermal reaction between F 2 and CO in the presence of O 2 [26,27].…”

The Trifluoromethoxycarbonyl Radical CF3OCO

“…The observed CF 3 /CO 2 band absorbance ratio is identical to the same band absorption ratio in a low-pressure flash pyrolysis study of CF 3 C(O)OOC(O)CF 3 with subsequent quenching of the products in a Ne matrix, in which the molar ratio CF 3 :CO 2 is found to be 1:1. [18] Therefore, the thermal reaction of CF 3 O with CO proceeds according to Equation (4) (see above).…”

“…Several experimental [20,21] and theoretical [22,23] studies have examined the reaction [Eq. (18)]. CF 3 CO 3 CF 3 CO (18) In this reaction, the reaction enthalpy (for the gas phase) D R(18) H o 298 was calculated to be À 24 kJ mol À1 .…”

“…(18)]. CF 3 CO 3 CF 3 CO (18) In this reaction, the reaction enthalpy (for the gas phase) D R(18) H o 298 was calculated to be À 24 kJ mol À1 . [22,23] Theoretical methods: All calculations were performed with the Gaussian 98 software package [24] using the density functional theory (DFT) calculations.…”