Inamul Haque

Partial Molar Volumes and Partial Molar Adiabatic Compressibilities of Fe(III) Tetrafluoroborate Complexes with DMSO, Pyridine, and Pyridine Derivatives

The apparent and limiting apparent molar volumes of dilute aqueous solutions of KBF4, and the complexes [Fe(DMSO)6](BF4)3, [Fe(Py)4(H2O)2](BF4)3, [Fe(4-Mepy)2(H2O)2](BF4)3, and [Fe(4-Etpy)2(H2O)2](BF4)3 were determined from density data measured at 5, 15, and 25°C. The apparent and limiting apparent molar adiabatic compressibilities of these complexes were determined from ultrasonic sound velocities measured at the same temperatures in dilute aqueous solutions. The volume change associated with complex formation is discussed in terms of the nature of the coordinate bond and also the role of the central metal atom and ligands in the solvation behavior of these complexes.

Viscosities and densities of tetraalkylammonium bromides in dimethylformamide-water mixtures at 25 and 35°C

Viscosity and desity data for KCl, KBr, Me4NBr, Et4NBr, Pr4NBr, and Bu4NBr from 0.005 to 3M in aqueous dimethylformamide solutions at 25°C and 35°C are presented. The data for dilute solutions were analyzed by means of the Jones-Dole equation and the ionic B coefficients evaluated. The data for concentrated solutions were analyzed by the Breslau and Miller equation and the effective flow volume, V3 of the electrolytes obtained as a function of concentration. The limiting effective flow volume, Veo was obtained from the Vand equation in the form used by Eagland and Pilling and it is shown that B=2.5 Veo. With increasing DMF concentration Veo increases for Me4NBr but decreases for Pr4NBr and Bu4NBr. The same effect was observed by increasing temperature. This behavior is explained in terms of the structuring effect of the constituent ions and the effect of DMF on the overall structure of the binary solvent.

The extraction of sulfate sulfur from coals by organic acids

Abstract Determination of sulfate sulfur in coal has been done by using organic acids, namely: acetic acid, oxalic acid and tartaric acid. The results have been compared with those of the ASTM HCl method. It is found that 0.5 M tartaric acid is a suitable reagent by which sulfate sulfur can be effectively extracted. Minor increases of sulfate sulfur in the tartaric acid extraction over that of HCl extraction may be correlated with the solubility of sulfate minerals which seem to be unleached with the mineral acid. This has been verified by studying the solubilities of gypsum and pyrite in the tartaric acid solution. Increased solubilities of gypsum and of sulfate obtained from pyrite have been found as the concentration of tartaric acid is increased. The variation of sulfate sulfur content in the extractions of 0.5 M tartaric acid and 4.8 M HCl is not significant. As the mineral acid could degrade the organic sulfur (which can affect its determination, calculated by difference), the use of tartaric acid is strongly recommended for the determination of sulfate sulfur in coal.

Viscosity of Potassium Trioxalato Complexes of Al(III), Fe(III), Co(III), and Cr(III) in Aqueous Solution Between 15° and 35°C

The viscosity of dilute aqueous solutions of K3[AI(ox)3]·3H2O, K3[Fe(ox)3]·3H2O, K3[Co(ox)3]·3H2O, and K3[Cr(ox)3]·3H2O complexes, as well as K2(ox)·H2O, were measured between 15 and 35°C. Those of CoCl2, 6H2O, FeCl3, A12(SO4)3·18H2O, and CrCl3·6H2O were measured at 25°C. These data were analyzed by the Jones–Dole equation. The ionic B coefficients of the above complex anions were discussed in terms of ion–solvent interactions and the overall change in ΔB associated with complex formation.

Partial molar volumes and partial molar adiabatic compressibilities of potassium trioxalato complexes of Al(III), Fe(III), Co(III), and Cr(III) between 15° and 35°C

The apparent and limiting apparent molal volumes of dilute aqueous solutions of K3[Al(ox)3] · 3H2O, K3[Fe(ox)3] · 3H2O, K3[Co(ox)3] · 3H2O, and K3[Cr(ox)3] · 3H2O complexes were determined from density data measured at 15°, 25°, and 35°C. The apparent and limiting apparent molal adiabatic compressibilities of these complexes were determined from measured ultrasonic sound velocities at 15°, 25°, and 35° in dilute aqueous solutions. The volume change associated with complex formation is discussed in terms of the nature of the coordinate bond and the overall hydration behavior of these complexes.