Effects in the Solid-State Infrared Spectrum of Cyanuric Acid

Aqueous solubility of alkylamino-s-triazine as a function of pH and molecular structure

“…An opposite trend is observed in the 2-hydroxytriazines, as this class is commonly named, where solubilities increase as IV-alkyl complexity increases. Infrared spectra (Padgett et al, 1957) and x-ray diffraction studies (Wiebenga, 1952) have indicated that crystalline trihydroxytriazine (cyanuric acid) molecules have a triketo-triamino configuration, while in aqueous solution there is a tautomeric equilibrium between the above keto form ( -NHCO -) and an enol form (Cignitti andPaoloni, 1964, Hirt andSchmitt, 1958). The low solubility of the hydroxytriazines in Table I as a whole can be reasonably attributed to strong dipole-dipole attractive forces between the amido groups of adjacent molecules in the solid phase.…”

Comment on “Density functional theory studies on molecular structure, vibrational spectra and electronic properties of cyanuric acid”

“…Padgett and co-authors compared three infrared spectra of solid cyanuric acid [25] obtained using the following approaches: (i) thin film sublimed onto rock salt; (ii) compound pressed in a KBr disk, and (iii) the acid pressed in a NaCl disk. It was shown that the experimental spectra differ and depend on the host, on the sampling conditions (temperature, pressure) and presence of impurities (humidity).…”

Quantitative Analysis of Mono- and Polybasic Benzene Carboxylic Acids in Potassium Bromide Disks by Infrared Spectroscopy

“…Some anomalies in the infrared spectra of the benzene carboxylic acids dispersed in potassium bromide disks are discussed in relation to analytical applications. XFRARED spectra of solid substances I are conveniently obtained, without recourse to solvents, by a technique involving preparation of dispersions of the sample in an alkali halide (2, 3,7,[9][10][11]. The low solubility of polar compounds-e.g.…”

“…Some anomalies in the infrared spectra of the benzene carboxylic acids dispersed in potassium bromide disks are discussed in relation to analytical applications. Infrared spectra of solid substances are conveniently obtained, without recourse to solvents, by a technique involving preparation of dispersions of the sample in an alkali halide (2,8,7,(9)(10)(11). The low solubility of polar compounds-e.g., certain benzene mono-and polycarboxylic acids-in liquids which possess high optical transparency in the 10-to 15-micron region of the spectrum led to a reexamination of the alkali halide pellet method for quantitative infrared spectrometry in this laboratory.…”

“…The alkali halide method is not without complications which arise from the fact that true solutions may not be formed, in general, in the preparation of the pellets. The dispersions of solid samples may show spectral features originating from orientation effects (1), polymorphism (5), adsorption (8), isomerization, the Christiansen effect (8), formation of mixed crystals (4), and other less well-defined phenomena (7).…”