борогидриды

A study of the solubility in the ternary systems NaBH₄–NaOH–H₂O, KBH₄–KOH–H₂O, NaOH–NaBO₂–H₂O и KOH–KBO₂–H₂O is of special fundamental and practical interest. The first two systems are used as a fuel and as a hydrogen source in hydrogen power engineering that includes the low-temperature fuel cells; borohydrides are converted into metaborates. Hence, the last two systems represent the discharged by-product.

The paper studies the influence of temperature (50–100°C) and alkalinity (C OH – = 2.33–9.53 M) of aqueous solutions on the hydrolysis (self-destruction) kinetics of borohydride ions BH₄^– Characteristic peculiarities of the kinetic curve have been established and formulae to approximate the temperature-concentration dependence of the hydrolysis rate are proposed. An increase in temperature leads to an increase in the rate constant k of borohydride hydrolysis, and the temperature dependence of k satisfactorily obeys Arrhenius' equation.