О КОМПЛЕКСООБРАЗОВАНИИ В СИСТЕМЕ «СУЛЬФАТ ХРОМА (III) – СУЛЬФАТ АЛЮМИНИЯ – СУЛЬФАТ ТИТАНИЛА – ВОДА»

Abstract

The application of heteropolynuclear complex compounds for leather tanning process is the alternative of traditional chrome tanning agents and allows solving a number of issues of leather factories: to improve the quality of products, expand its product range, ensure the principle of low-waste production using environmentally sound chemical materials, and decrease the airway cancer rate of the employees. The paper describes the study of complex formation in the “chromic sulfate (III) – aluminum sulfate – titanyl sulfate – water” quadruple system using two methods: Ostromyslenskiy-Zhoba method and the isothermal solubility method. The author used Ostromyslenskiy-Zhoba method to carry out the spectrophotometric study of solutions containing ions of chrome (III), titanyl and aluminum in the simultaneous presence of cations of two and three metals. Absorption spectra were measured in the area of wavelengths of 300–700 nanometers in an hour after preparing a solution. Studying the dependencies of the light absorption coefficients on the aluminum sulfates molar fraction at various wavelengths, the author determined the feasibility of chrome-titan-aluminum complex compounds formation. However, this method did not give a straight answer on the existence of fixed composition and a certain amount of complex particles in solutions. Further research using the isothermal solubility method defined the crystallization region of triple heteropolynuclear complex compounds containing chromium (III), titanium and aluminum. To carry out the experiment, the author added the third salt to saturated euthonic and peritonic solutions of initial triplex systems until the formation of new solid phase. The derived solutions were thermostated at the temperature of 25° С. Using Mertslin’s method of sections, the composition of solutions was defined according to the “composition – refraction index” characteristic curves. The refraction index constancy denoted the establishment of equilibrium between solid and fluid phases. Isothermal solubility method allowed identifying the estimated bulk compositions of chrome-titan-aluminum complexes calculated using the solubility diagram.