Der Mechanismus der Anionkatalyse des Nitramidzerfalls in wäßriger Lösung von neuen Gesichtspunkten der Säure-Basen-Katalyse aus und die kinetische Bestimmung der Entropie der Wasserstoffbrückenbindung des Wassers

Eyring equations for the coefficient of the water catalysisk _w and for the coefficient of the catalysis of a series of anions with the same activation enthalpy as waterk _A ^? give for the difference of the activation entropies $$\Delta S_{A^ - }^* - \Delta S_w^* = \Delta S = R ln\frac{{k_{A^ - } }}{{k_w }}.$$ While at the general acid-base catalysis of the mutarotation of α-glucose ΔS is the entropy change in the reaction of the hydrated oxonium ion with the hydrated anion to the hydrated acid, ΔS for the decomposition of nitramide is the entropy change in the reaction of the hydrated oxonium ion with the hydrated anion to the unhydrated acid. The mechanism of reaction leads over the proton transfer from the tautomer of nitramide to the anion by the water molecule of the hydrated anion forming the unhydrated acid. As the conjugated acid for the hydroxide ion catalysis of the mutarotation of α-glucose and for the decomposition of nitramide is water, the entropy change of the breaking of the hydrogen bonds of water H₂O...H?O?H...OH₂ can be calculated. This entropy value agrees with that found byWalrafen from the Raman-spectrum of water. “Brönsted catalysis law” is replaced-according to the author — by the linear relation of ΔS to the logarithm of the base constantK _B , or to the change of the free enthalpy of the acid ionization, resp. For the general base catalysis of the α-glucose mutarotation $$\Delta S = \beta R \ln K_B ,$$ for the general base catalysis of the decomposition of nitramide, for which no general acid catalysis exists, $$\begin{gathered} \Delta S = R \ln K_B , \hfill \\ therefore \beta = 1. \hfill \\\end{gathered}$$ The deviations from this relation were cleared up by thermodynamic calculations. The coefficient of the general base catalysis of the mutarotation of α-glucose β is due to the hydrogen bond of water.