Browsing by Author "Lilov M.E."

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    Conversion of ammonium cyanate solution at 293.15 K
    (2018-01-01) Lilov M.E.; Kirilov P.P.
    Conversion of 0.064 mol L-1 ammonium cyanate solution has been studied at 298.15 K over a time period of 90 days. The data is obtained by periodic measurement of the electric conductivity, pH and concentration of the main species of the solution such as cyanate, urea, ammonim carbonate and ammonium hydrogencarbonate. The distribution of the species in the solution during this period is presented in graphic mode. The pH value increases gradually due to the formation of NH4HCO3 and (NH4)2CO3. The spontaneous conversion of the ammonium cyanate ions to a neutral substance, urea, is accompanied by a sharp conductance decrease. Ammonium cyanate hydrolysis to NH4HCO3 and (NH4)2CO3 proceeds to a much smaller extent than that of urea conversion. During 90 days storage of the solution at 298.15 K the degree of overall transformation of ammonium cyanate is found equal to 96.3 %.
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    STABILITY OF UREA SOLUTIONS IN PRESENCE OF BUFFERING ADDITIVES
    (2021-01-01) Lilov M.E.
    The stability of urea water solutions, containing 20 % nitrogen in presence of phosphates: [(NH4H2PO4+ (NH4)2HPO4], [KH2PO4+K2HPO4] and citric buffering additives: potassium citrate, citric acid and glycine has been studied. The study was carried out at temperature 298.15 K for a period of 150 days by periodic measurement of the electrical conductivity and pH of solutions. It was found that the most suitable composition for liquid fertilizer among the urea water solutions with additives of citrate buffers is the urea solution with additive of citric acid as well as mixture of citric acid and glycine. A possibility was shown to study the behavior of urea solutions through periodical measurement of two very easy to register and very precise parameters - pH and conductivity during the prolonged storage and the possibility for stabilizing of these solutions.