Reaction order, rate equation and Arrhenius parameters

2 REACTION ORDER, RATE EQUATION AND ARRHENIUS PARAMETERS 

The thermal decomposition of propionaldehyde is a homogeneous reaction in a seasoned vessel - however, in a clean one, the reaction proceeds more slowly. 

If decomposition goes to completion, the initial pressure approximately doubles. It has been found that the rates determined on the basis of pressure change and by analytical methods were in reasonable agreement - °°. However, recently Mirta et pointed out that, at low initial pressures and at high temperatures, the progress of the reaction cannot be characterized strictly by pressure measurements. 

Boyer and Niclause - reinvestigated the kinetics of the reaction at lower temperatures (421-496 °C). According to their experimental results the initial rate can be given by the following expression 

In the temperature range 515-565 °C and at 100-250 torr pressures, Marta and Szab6 ° ° found a -order rate expression to be valid both for the initial rates as well as for the pressure increases measured during experiments. Their rate coefficient is given by 

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