Examples of rate equations for industrially important reactions

Examples of Rate Equations for Industrially Important Reactions 

For most gas-solid catalytic reactions, usually a rate equation corresponding to one form or another of the Hougen and Watson type described above can be found to fit the experimental data by a suitable choice of the constants that appear in the adsorption and driving force terms. The following examples have been chosen to illustrate this type of rate equation. However, there are some industrially important reactions for which rate equations of other forms have been found to be more appropriate, of particular importance being ammonia synthesis and sulphur dioxide oxidation 42 . 

They concluded that the applicable rate equation was  

Equation 3.84 was consistent with a mechanism whereby the reaction between ethylene and water adsorbed on the surface was rate-controlling but without strong adsorption of the product ethanol. Commercially at the present time, phosphoric acid on kieselguhr is the preferred catalyst. 

This equation can be interpreted as indicating a surface reaction being rate-controlling (although the controlling step could be adsorption), but all the species involved being only weakly adsorbed i.e. the adsorption terms KeP , KSPS, K PH, which would otherwise appear in the denominator, are all much less than unity. 

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