The Photolysis of Trifluoroacetic Acid Vapor

Abstract

The photolysis of CF3COOH vapor has been studied a t temperatures between about 90 and 190" C, using light of wavelengths between 2000 and 2200 -4. The major products were C 0 2 and C2F6, with smaller amounts of CO, Hz, and CFaH. A marked reduction in the yields of C o n , CO, and H z with increasing pressure of added isobutane or 1-butene has been interpreted to imply the presence of free COOH radicals in the system, which is supported by the tentative identification of formic and oxalic acids as products of the photolysis. It is thought that the reaction CFaCOOH + hv + CF3 + COOH represents the main primary photolytic process, with the minor processes CF3COOH + hv + CF3 + COz + H and CF3COOH + hv --t CF3 + CO + OH accounting for no more than 27 and 7% respectively of the total a t 165' C.Some tentative conclusions have been drawn about the reactions of COOH radicals. In the present system, the disproportionation reaction, 2COOH -+ COz + HCOOH, appears to predominate, with the decon~position reaction, COOH + COz 4-H, apparently of minor importance a t 165' C.

Overtone-Induced Chemistry of Trifluoroacetic Acid: An Experimental and Theoretical Study

“…Many experimental studies have been made of the dissociation of trifluoroacetic acid. In particular, the dissociation has been effected by UV light, ,− multiple IR photons, heat, − intermolecular energy transfer from SF 6 , and gamma radiation. , Products that have been identified include CO 2 , C 2 F 2 , CO, CF 3 H, H 2 , CF 2 , COF 2 , CF 3 COF, C 2 F 4 , SiF 4 , CF 3 CO 2 CF 2 H, and HF. In addition, some products have been inferred but not observed directly: CF 3 , COOH, and F 2 CCO 2 .…”

Reaction between hydroxyl (deuteroxyl) radicals and carbon monoxide at temperatures down to 80 K: experiment and theory

“…Back,17•18 the HOCO radical was proposed as an intermediate in both the thermolysis of phenylacetic acid16 and the photolysis of trifluoroacetic acid. 17 In 1964, Ung and R. A. Back proposed HOCO as an addition product of the reaction of OH and CO.18 Although there have not been any direct, spectroscopic observations of HOCO formed as an addition product of reaction between OH and CO, three papers have recently reported the high-resolution microwave19 and infrared20 spectra of the HOCO and DOCO radicals.…”

Photoreductive defluorination of trifluoroacetic acid (TFA) in the aqueous phase by hydrated electrons

“…Studies have shown that TFA cannot be decomposed effectively by methods such as anaerobic or aerobic biodegradation [22], conventional advanced oxidation (e.g., ozone oxidation or •OH oxidation) [23], or high-temperature pyrolysis (e.g., 165°C) [24]. Some researchers have demonstrated that TFA can be decomposed by photocatalytic oxidation.…”