The Extraction of Ferric Chloride by Isopropyl Ether. I. The Significance of Water in the Extracted Iron Complex

Proton Transfer, Acid‐Base Catalysis, and Enzymatic Hydrolysis. Part I: ELEMENTARY PROCESSES

“…If the recombination of H+ and HO-is sufficiently fast, then 1 7 1 2 Q 1 TI)' L , T23 where & = k31cX and = k 2 3 C~~. In this case, there is a pH value (close to the pK value) at which 7 1 3 and 723 become equal k31 Ex = k23& (24) This means that 4 P = S2, and the square-root term in Equation (16) disappears. Only one time constant is then obtained:…”

“…The rate constants k31 and k23 are both of the same (maximum) order of magnitude (see Table 4g). Condition (24) is fulfilled at pH 7.2 (7 m lO-lO/Co sec, where CO = total molar concentration of imidazole). Attainment of the overall equilibrium, which is characterized by a single relaxation time, is fastest at this pH.…”

Solvent Extraction of Inorganic Species.

“…Solvation by dibutyl ether was shown (114) to involve three molecules of ether, by studying the change of the distribution coefficient with the concentration of ether in carbon tetrachloride or benzene. The primary species may be [0(H0(C4H9)2)3] + FeCl4, further solvated by water and ether (111), but species where the proton is primarily solvated by water only (225) have also been proposed. In low dielectric constant solvents, the primary species may aggregate by dipole interactions of the ion pairs, and may associate with ion paired hydrochloric acid.…”

Solvation of Extracted Complex Metal Acids. III. The HFeCl4-Diethyl Ether System

“…Figure 2 shows plots of log E vs. log mole fraction of (C2H5) 20 for trace iron extraction from acidified LiCl solution by (C2H5)20-CeH6 mixtures. The slopes of the straight (solid) line portions, obtained by a leastsquares analysis of the data giving each point equal weight, are 4.26, 4.27, 4.31, 4.36, and 3.90 for curves 1-5 in that order.…”