A. Pisareva, R. Pisarev, Y. Dobrovol’skii
Jul 3, 2009
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Influential Citations
7
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Journal
Russian Journal of Electrochemistry
Abstract
Effects of environment conditions (humidity and temperature) on the proton conductivity of aminobenzenesulfonic acids: 2-amino-(orthanilic) acid (I), 3-amino-(metanilic) acid (II), 4-amino-(sulfanilic) acid (III), their general formula NH2C6H4SO3H, and 3-amino-4-hydroxobenzenesulfonic acid (IV) [NH2(OH)C6H3SO3H), as well as (for sake of comparison) inorganic aminosulfonic acid [sulphamic acid (NH2SO3H)] (V) are studied. All above-listed compounds are zwitter-ions: they contain a fragment NH3+SO3−. The presence of this structural fragment affects the thermal stability of the compounds; according to the mass-spectrometry analysis data, the decomposition of the SO3-fragment begins at the following temperatures: (I) −339, (II) −370, (III) −320, (IV) −278, and (V) −220°C. It is shown that the increase of the environment relative humidity up to 95% results in the increase of the aminobenzenesulfonic acids proton conductivity from 10−9–10−8 to 10−5 S cm−1; sulphamic acid, to 10−4 S cm−1. At that, the amount of adsorbed water does not exceed 0.2 moles per 1 sulfo group in all cases. The conductance activation energy equals 0.2 eV at a relative humidity of 95%.