Polarography of tin(IV) in presence of chloranilic acid

Abstract

Parker et al. ( 9) have also determined the pKa of BCG in DMF, and report a value that is approximately 1.2 units lower than obtained in the present studies. These workers (9) give pKa values for acetic acid, benzoic acid (Table I), and p-nitrophenol (Table II) that are 1 to 2 units below the values obtained by other workers. However, Parker ( 14) has recently revised the value for p-nitrophenol in DMF to ca. 12.2, and has indicated that this revision will change the pKa values reported by Parker et al. ( 9) for other compounds.Salicylic Acid. Absorption measurements of BCG were made in salicylic acid-sodium salicylate buffers. The isosbestic point remained at 504 nm. Results are listed in Table VI. The linear plot of pcH against log [(A-Aa)/(Ab-A)] has least-squares slope and pcH intercept of 1.1 and 8.86, respectively.Juillard and Mallet (13) give 8.23 as the value of the pKa for salicylic acid in DMF. These workers used measurements based on picric acid, for which widely-differing pKa values have been reported (Table II). The concentration of picric acid in the salicylate buffers is not stated. Petrov and Umanskii (11) have shown that the pKa of picric acid in DMF is extremely concentration dependent.

Selectivity studies on anion-selective membrane electrodes

“…The solvents were CDC1S and DMSO-de. 2-Chloroallylphthalimide 2; 4.53 (m, 2H, -NOV), 5.44 (m, 2H, =CH2), and 7.9 (m, 8H, arom.). 1,4-Diphthalimidobutane 6; 1.7 (t, 4H, insulated methylene), 3.6 (t, 2H, -NCH2CH20-), and 7.8 (m, 8H, arom.).…”