[Chem] Problem finding a source for reaction rate constant

In summary: I found this article that cites some values for the conversion and it looks like the values that you found were more reasonable. In summary, the reaction was catalyzed by a palladium catalyst and the rate constant was found to be k=5.8 x 10^{-5} M^{-1}s^{-1} which was significantly higher than the value that you found from the old sources. In summary, the reaction was catalyzed by a palladium catalyst and the rate constant was found to be k=5.8 x 10^{-5} M^{-1}s^{-1} which was significantly higher than the value that you found from the old sources.
  • #1
AntorPritcher
2
0

Homework Statement



I had an assignment where I needed to calculate reaction rate constants at different temperatures. I was supposed to use ab initio method (meaning I should use Spartan software), molecular partition functions and Eyring equation. The reaction was:

[itex]H+HD \stackrel{}{\leftrightarrow} HHD \stackrel{}{\leftrightarrow} H_{2} + D [/itex]

Where H is hydrogen and D deuterium and HHD transition state. It worked very well I've calculated rate constants and answered all questions but one. The last thing asked to do was to compare results with literature values. I remember my instructor said some people actually did measure rate constant for this reaction experimentally, so I figured there will be a publication about this. The problem is that I can't find it, I don't know if this reaction has some specific name so that I can use it in my search queries. I've tried searching with whole reaction equation as a query but I've got nothing with Google Scholar and ISI Web of Knowledge. I'll be grateful if somebody can point me in the right direction.
 
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  • #2
You know more than me - I could not do that calculation, but I would call that a hydrogen-exchange reaction and I see that googling that name leads to relevant-seeming articles.
 
  • #3
epenguin said:
You know more than me - I could not do that calculation, but I would call that a hydrogen-exchange reaction and I see that googling that name leads to relevant-seeming articles.
Thanks! The deadline for returning was yesterday mindnight and I've managed to find some sources in NIST Kinetics Database few ours before deadline. They were very old and the values were very odd, so I looked up publications that cited sources mentioned in NIST and found some acceptable values in more recent publications.
Your guess is close, this reaction has several names in literature, hydrogen-deuterium conversion, isotope exchange reaction.
 

1. What is a reaction rate constant?

A reaction rate constant is a measure of the speed at which a chemical reaction occurs. It is a proportionality constant that relates the concentrations of reactants to the rate at which products are formed. It is denoted by the symbol k and is specific to a particular reaction at a given temperature.

2. How is the reaction rate constant determined?

The reaction rate constant can be determined experimentally by measuring the initial rate of the reaction at different concentrations of reactants. This data is then used to calculate the rate constant using mathematical equations, such as the rate law. The rate constant can also be estimated using theoretical methods, such as transition state theory.

3. What factors can affect the reaction rate constant?

The reaction rate constant can be affected by several factors, including temperature, concentration of reactants, presence of catalysts, and the nature of the chemical bonds involved in the reaction. Changes in any of these factors can lead to changes in the rate constant and ultimately affect the speed of the reaction.

4. How does the reaction rate constant relate to the overall rate of a reaction?

The reaction rate constant is directly proportional to the overall rate of a reaction. This means that a higher rate constant will result in a faster overall reaction rate, while a lower rate constant will result in a slower overall reaction rate. The relationship between the rate constant and the overall rate of a reaction is described by the rate law equation.

5. Can the reaction rate constant change over time?

The reaction rate constant is typically considered to be constant for a given reaction at a specific temperature and pressure. However, it is possible for the rate constant to change over time due to factors such as changes in temperature or the presence of impurities in the reaction mixture. In these cases, the rate constant may be affected and the overall rate of the reaction may change as well.

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