Open AccessThe kinetic research of hydrolysis in the systems used in borohydride hydrogen power engineering
Author(s) -
Veronika Olegovna Romanova,
AUTHOR_ID,
Aleksei Vladimirovich Churikov,
К. В. Запсис,
I. M. Gamayunova,
Mikhail Alekseevich Churikov,
Mikhail Yur'evich Vasil'kov,
AUTHOR_ID,
AUTHOR_ID,
AUTHOR_ID,
AUTHOR_ID,
AUTHOR_ID
Publication year - 2013
Publication title -
èlektrohimičeskaâ ènergetika
Language(s) - English
Resource type - Journals
eISSN - 1680-9505
pISSN - 1608-4039
DOI - 10.18500/1608-4039-2013-13-1-3-11
Subject(s) - borohydride , hydrolysis , alkalinity , chemistry , aqueous solution , arrhenius equation , hydrolysis constant , inorganic chemistry , reaction rate constant , catalysis , hydrogen , kinetics , kinetic energy , activation energy , atmospheric temperature range , ion , thermodynamics , organic chemistry , physics , quantum mechanics
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. The influence of solution alkalinity on the borohydride hydrolysis rate was explored. Within the temperature range studied, the k = f(C OH -) curve consists of two fragments, each with the prevalence of one of two different mechanisms (paths) of borohydride hydrolysis. In highly-alkaline aqueous solutions, non-catalytic hydrolysis mainly occurs, whose rate is determined by temperature, being pH-independent. At lower alkalinity, the hydrolysis rate sharply increases due to catalysis by H+ ions. A power dependence of k on the H+ concentration has been found; the point where the mechanisms are switched is determined by temperature.