Infrared Spectrum of Trifluoroacetic Acid Vapor

Abstract

The infrared absorption of trifluoroacetic acid vapor in the region between 2 and 24 μ has been studied as a function of temperature. At room temperature both monomer and dimer molecules are present, while at 100°C the vapor is predominantly monomeric. On the basis of the resulting intensity changes it has been possible to conclusively identify the bands due to the two species. A partial assignment of the fundamental modes of vibration has been made using these data and the previously published spectrum of the deuterated acid. The heat of dissociation (ΔH) for the dimer-monomer reaction has been determined from the temperature dependence of the OH stretching bands and found to be 13.7±0.4 kcal/mole.

Effect of neutralization and cross-linking on the thermal degradation of chitosan electrospun membranes

“…Compounds like pyrazine are the most important products among the volatiles that were identified. A strong absorption band was observed at 1150 cm -1 for the electrospun samples heated until 300 ºC (figure 6), corresponding to the C -F stretching band due to the -NH3 + CF3COO -salts previously formed during polymer dissolution in a TFA/DCM mixture, and proves the existence of such residues, probably located in the side groups of the electrospun polymeric chains [26,27]. The absorption band at 1150 cm -1 was also observed for the chitosan samples submitted to ethanol neutralization and cross-linking with GA (data not shown).…”

Infrared matrix-isolation spectroscopy of trifluoroacetic acid hydrates

“…Following the infrared observation in gas phase [14,15], Redington and Lin reported infrared studies of TFA and TFA dimer in rare gas matrices [16,17]. The vibrational assignment of TFA monomer was complemented by similar experiments with isotopomers [18].…”

Novel chromium trinuclear trifluoroacetate complexes Cr3(μ3-O)(CF3COO)6(CH3COOH)2(CF3COO) and Cr3(μ3-O)(CF3COO)6(CH3COOH)2(THF): Synthesis and crystal structure

“…The bond lengths of the terminal CH 3 COOH molecules differ substantially: for C-O(H) and C-O(Cr), this difference is 0.07 Å on average. Although not all H atoms of OH groups in carboxyl fragments of structure I are localized, the characteristic elongation of the C(13)-O (15) and C(15)-O(17) bonds suggests that compounds I and II contain particularly molecules, rather than anions of acetic acid. It is interesting that structure II has intermolecular hydrogen bond O-H···O formed by the H atom of OH group of one acetic acid molecule and carboxyl O atom of another molecule.…”

“…Obviously, this can be explained by different potentials of transformations M 2+ M 3+ (E 0 being 0.771, 1.92, and -0.424 V for iron, cobalt, and chromium, respectively [13]). This fact is of a particular interest because of a large number of trinuclear oxocarboxylate Fe and Co complexes reported in the literature [14,15]. For instance, the dissolution of metallic iron in an aqueous solution of trifluoroacetic acid gives heterovalent complex…”