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Kinetics of the reaction of niobium pentachloride with water vapor
Author(s) -
Ingraham T. R.,
Whalley B. J. P.
Publication year - 1963
Publication title -
the canadian journal of chemical engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.404
H-Index - 67
eISSN - 1939-019X
pISSN - 0008-4034
DOI - 10.1002/cjce.5450410608
Subject(s) - niobium , niobium pentoxide , phosphorus pentachloride , diffusion , inorganic chemistry , chemistry , reaction rate constant , reaction rate , hydrogen chloride , chloride , hydrogen , chemical kinetics , kinetics , materials science , thermodynamics , organic chemistry , catalysis , physics , quantum mechanics
When niobium pentachloride is exposed to moist air, hydrogen chloride is liberated and hydrated niobium pentoxide or niobic acid remains. It is believed that the rate of the reaction is controlled by the rate of diffusion of water across a layer of unidentified intermediate product of constant thickness (about 0.2 mm.). The constant thickness of the layer is maintained by the spalling and cracking of the product after it exceeds a critical thickness. Since the reaction takes place at an interface between the niobium pentachloride and the layer of intermediate, it is necessary to normalize the results for the decrease in interfacial area as the reaction proceeds. When this is done, the rate of the reaction, expressed in terms of grams of niobium pentachloride reacting per square centimetre of interface per hour, is:\documentclass{article}\pagestyle{empty}\begin{document}$$ {\rm Rate} = \left({7.7 \pm 0.4} \right) \times 10^4 \left({p_s /p} \right)\exp | - \left({8.1 \pm 0.6} \right) \times 10^3 |/RT $$\end{document}