Solubility products of potassium and triisoamyl-n-butylammonium picrates and tetraphenylborates in ethanol-water mixtures at 25.deg.C

Abstract

N. Y. 11210 Solubility (ion-activity) products of potassium picrate (KPi), potassium tetraphenylborate (KBPhi), and triisoamyl-n-butylammonium picrate (TABPi) were determined at 25°C. over the entire range of ethanol-water solvents, and those of triisoamyl-nbutylammonium tetraphenylborate (TAB BPfu), in 40 to 100 weight % ethanol in water. Molar absorptivities of picrate and tetraphenylborate ions were obtained as a function of ethanol-water composition in the visible and ultraviolet regions of the spectrum, respectively. Saturated solutions of the title electrolytes were analyzed quantitatively by spectrophotometry. Mean ionic activity coefficients of the electrolytes in saturated solutions were evaluated from studies of their solubility as a function of ionic strength varied by means of added lithium chloride. At solubilities < 10"3 M, activity coefficients obeyed the limiting Debye-Hückel law.

A Rapid Turbidimetric Potassium Test Modified for Use with the Pressurized Hot‐Water Extraction

“…In adapting the sodium tetraphenylborate procedure for use with PHW extraction, the procedure outlined by Sunderman and Sunderman (1958) was chosen among the many reviewed (Sunderman and Sunderman, 1958;Schall, 1957;Brabson, 1966;Gloss, 1953;Cluley, 1955;Kallman, 1959;Pflaum and Howick, 1956;Motomizu et al, 1992;Dill and Popovych, 1969) primarily because it already involved a water extract and was a turbidimetric procedure read directly on the spectrophotometer. Although the procedure was originally intended to measure blood serum K, the extensively tested protocol had precipitation characteristics similar to recommended soil analysis procedures (Schall, 1957).…”

Potentiometric determination of solubilities of physiologically active amine salts

“…A photometric method for determining the SP values of picrates and tetraphenylborates of physiologically active amines was described in [2].…”

“…However, it is possible to compare the solubilities of these salts, which are related to SP via Eqs. (2) and (8). Judging from the calculated values, the solubility of cetylpyridinium TPB is three times that of chlorhexidine TPB.…”

“…According to the aforementioned photometric method, the SP values are calculated using data on the equilibrium concentrations of anions of the precipitated amine, which are determined from the optical absorption of the aqueous phase occurring in equilibrium with the precipitate [2]. In the proposed potentiometric technique, the main instrument is the ISE, reversible with respect to the cation of the corresponding physiologically active amine.…”

“…In the proposed potentiometric technique, the main instrument is the ISE, reversible with respect to the cation of the corresponding physiologically active amine. On the whole, the photometric methods of analysis of physiologically active amines [2,5], as well as the chemical and microbiological techniques [6 -9], are rather complex and time-consuming. In contrast, the potentiometric measurements offer a convenient and rapid method for the investigation of processes with the participation of physiologically active amines [10 -12].…”