While studying the effect of residence time on reactants conversion to product, it was noticed that after some time the conversion is no longer increasing, but remain almost stable. Generally, it is known that reaction rate decrease with time, but this may not be a sufficient reason for the observed trend. Kinetically/mass transfer limited phenomenon may not also apply here considering that the reaction is kinetically limited in the initial stage, so in theory it can not change to mass transfer later on. A possible reason but not sure about is that the reaction order or mechanism could change after sometime.
Could you provide more details?
You may consider product inhibition with Languir-Hinshelwood model to describe the phenomenon.
What reaction - single?, reversible?, one reaction or more?, in the presence of catalyst? ............ The result indicates the achievement of chemical equilibrium. So probably a reversible reaction. Regards,
Hi,
The change of rate of chemical reaction is explained by action rate constant.
In the case of a homogeneous réacton:
the variation of the reaction rate can not be explained by the change in the order of the reaction or reaction mechanism. It can be explained by the following factors:
variation of the initial operating conditions: examples; levels of the concentrations of the reactants, level of the initial pressure, use of catalyst, activation of the reaction either by thermal method, by light method or by electrical method.
In the case of many reactions carried out in the same chemical reactor, then the reaction mechanisms can be influenced by other reactions such as the consumption of intermediates or free radicals.
I proposed this answer according to what we understood. But if you describe the actual situation of your question (ie the type of reaction, the operating conditions, the types and flows of reagents and products, then I can propose a more specific answer).
I hope this answer will help solve the problem you are dealing with.
Best regards.
Dr. Adel OUESLATI
Where it is not known what the reaction is, under what conditions it occures, no relible answer is possible. The rate of chemical reaction can decrease with time, it can also increase and then decrease (autocatalitic reaction). There is also no the relationship between the order of chemical reaction and the behavior observed - no conversion changes. And I will repeat, I do not know. which once - the term "reaction order" refers to a single chemical reaction.
Or maybe the answer is the most trivial, that is, total consumption of the substrate. Regards,
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