Relationship Between Conversion, Selectivity, and Yield

A relationship between the yield, seleetivity and eonversion ean be obtained on the eomponents as follows. The eonversion of eom-ponent A is 

354 Modeling of Chemioal Kinetios and Reaotor Design The yield of eomponent B is C  

For a well-stirred tank reaetor involving a seeond order irreversible reaetion of the form aA -i- bB — rR -i- sS, the yield of R is 

For a plug flow or bateh reaetor, the yield of eomponent R is defined as 

For a cascade of well-stirred reactors, the yield of component R is defined as 

The following details mathematical expressions for instantaneous (point or local) or overall (integral) selectivity in series and parallel reactions at constant density and isothermal conditions. An instantaneous selectivity is defined as the ratio of the rate of formation of one product relative to the rate of formation of another product at any point in the system. The overall selectivity is the ratio of the amount of one product formed to the amount of some other product formed in the same period of time. 

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Sometimes, these definitions are mixed up in the literature. Eq. (8) describes the relationship between conversion, selectivity and yield ... 

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