pH-metric method determining the solubility and solubility products of slightly soluble salts of arbitrary composition

The developed method of determining KS from pH metric data has a number of advantages compared to those used traditionally. First, in place of the residual concentrations of the salt components, only the pH value of the saturated solution is used in the derived expressions. Thus, the number of independent variables, which need to be measured experimentally, is reduced. Furthermore, the potentiometric method, used to determine the pH, is sufficiently accurate, simple and universal and does not necessitate the use of ion-selective electrodes. At the same time, the residual concentrations are usually measured by chemical methods, which are inferior in most cases, for several reasons, compared to the potentiometric method. Second, the KS value calculated by the developed method has a thermodynamic character. The organization of the experiment must be appropriate to the applied equations. Therefore, it is necessary to draw attention to the need for high accuracy in the process of preparing the initial solutions, because the initial concentrations of the precipitate components are included in the calculation formulas. The developed method for determining Ks can be applied for systems of any degree of complexity, which contain additional complexing agents.

Determination of lipoids in the grains of leukocytes, According to Savinі (Wien. Sh. Woch., 1921. No. 46)

Determination of lipoids in the grains of leukocytes, According to Savinі (Wien. Sh. Woch., 1921. No. 46) for this purpose, glasses with lubricants are placed in a 5% solution of two chromium copper, washed and stained with a saturated solution of charlah in ethyl alcohol, followed by: washing, light coloring of the nuclei with a contrasting paint, again washing, drying and imprisoning in neutral glycerin or a thick solution of levulose.

OBTAINING HIGH QUALITY LITHIUM CARBONATE FROM NATURAL LITHIUM-CONTAINING BRINES

The aim of this work is to develop a new effective technology for producing high-quality lithium carbonate from natural lithium-containing brines. Freshly deposited aluminum hydroxide was used to separate lithium from the trace amounts of sodium and calcium. It was found that the completeness of lithium extraction from brines purified from magnesium depends on the sorbent dosage, phase contact time, mineralization, pH, and brine temperature. To extract lithium from brines with a mineralization of less than 100 g/dm3, it is necessary to introduce 4 mol of aluminum hydroxide per 1 mol of lithium in the brine. For brines with a mineralization greater than 200 g/dm3, the consumption of the sorbent providing the extraction of lithium more than 96% is 2.5 mol of aluminum hydroxide. Desorption of lithium chloride from lithium-aluminum concentrate is carried out by processing 4-5 canopies of concentrate in a Soxlet type apparatus with the same volume of distilled water. The resulting concentrated solution of lithium chloride is purified from calcium impurities in contact with a saturated solution of lithium carbonate. From a heated aqueous solution of lithium chloride purified from calcium impurities, lithium carbonate is precipitated by dosing a stoichiometric amount of a saturated solution of sodium carbonate into it. The precipitate of lithium carbonate is separated from the mother solution, washed with three portions of a saturated solution of lithium carbonate at a ratio of solid to liquid by weight equal to one to five, in order of decreasing the concentration of sodium in each portion of the wash water. The dried product contains at least 99.6% Li2CO3.

Solubility of folic acid and protonation of folate in NaCl at different concentrations, even in physiological solution

The solubility of folic acid was determined at 25 °C in 1.00 mol dm−3 and in 0.15 mol dm−3 NaCl (physiological solution) spectrophotometrically by measuring the absorbance of saturated solution at different hydrogen ion concentrations.