Ordens não inteiras em cinética química Non-integer orders in chemical kinetics

Starting from zero-, first-, and second-order integrated laws for chemical kinetics, some cases are shown which produce fractional orders. Taking the Michaelis-Menten mechanism as a first example, it is shown that substrate order can go from 1 to zero, depending on relative concentration of enzyme a...

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Bibliographic Details
Published in:Química nova 2010-01, Vol.33 (6), p.1412-1415
Main Authors: André P. Oliveira, Roberto B. Faria
Format: Article
Language:English
Subjects:
chemical kinetics
homogeneous catalysis
non-integer orders
Online Access:Get full text
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Summary:Starting from zero-, first-, and second-order integrated laws for chemical kinetics, some cases are shown which produce fractional orders. Taking the Michaelis-Menten mechanism as a first example, it is shown that substrate order can go from 1 to zero, depending on relative concentration of enzyme and substrate. Using other examples which show fractional orders higher than one and even negative (inhibition), it is shown that the presence of an equilibrium before or parallel to the rate determining step can be the reason for fractional orders, which is an indication of a more complex mechanism.
ISSN:0100-4042
1678-7064
DOI:10.1590/S0100-40422010000600035