Determination of pK_a values of fluorocompounds in water using ¹⁹F NMR

Abstract

Brønsted acidities of 19 fluorocompounds in the pKa range from 3.5 to 10 have been measured in aqueous solution using an approach involving absolute and relative pKa measurements with 19F NMR. 19F NMR has not been frequently used for determining pKa values, but it has a number of advantages, especially when relative values are considered: accurate concentrations not needed, tolerant to impurities, several compounds can be measured simultaneously, several uncertainty sources cancel out.

Efficient and reversible absorption of low pressure NH3by functional type V deep eutectic solvents based on phenol and hydroxypyridine

“…The acidity of HBDs varies in the order TMP > PhOH > MC (p K a = 10.08 for MC, p K a = 9.98 for PhOH, and p K a = 9.08 for TMP). 49,50 Evidently, the solubility of NH 3 in DESs increased with increasing acidity of HBDs, and 3-HP/TMP demonstrated the largest molar absorption capacity among three DESs. However, the gravimetric absorption capacity can provide practical evaluation of a gas absorbent.…”

Acid‐Base and Anion Binding Properties of Tetrafluorinated 1,3‐Benzodiazole, 1,2,3‐Benzotriazole and 2,1,3‐Benzoselenadiazole

“…The pK aH and pK a values of the studied compounds were evaluated both experimentally with UV-Vis [12] and/or 19 F NMR [13] techniques and computationally with DFT calculations and COSMO-RS approach [14] (Table 1). The experimental determination is based on the measurements of differences in the acidities or basicities of two acids or bases, respectively (ΔpK a or ΔpK aH values, respectively).…”

“…With both UV-Vis [12] and 19 F NMR, [13] the pK aH determinations were based on titrating solutions containing both the investigated compound and a reference compound, in order to obtain the spectra of solutions where both compounds are in partially protonated forms, as well as those of solutions where both compounds are fully neutral or fully protonated.…”

Synthesis of β‐Keto Sulfones by Oxy‐Sulfonylation of Alkynes in HFIP

“…The reaction could not occur employing HFIPÀ Me as solvent. This result may be ascribed to the elimination of the H-bond donor or weaker acidity [14] of HFIPÀ Me after the block of the hydroxy group. Moreover, cyclic voltammetry (CV) analysis of 2 a in different solvent of interest was performed.…”