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6.22: Untitled Page 145

  • Page ID
    18278
  • Chapter 6

    studied experimentally (Sankaranarayanan et al, 2008) in order to determine the factors affecting the selectivity (see Chapter 7) of ethylene and acetic acid. Make use of the pivot theorem to demonstrate that one must measure (as one possibility) the net rates of production for CH COOH , C H , H O and CO in 3

    2

    4

    2

    order to predict the net rates of production for C H , CO and O .

    2

    6

    2

    2

    6‐32. From Figure 6.32 we see that  ‐butylene has a very different structure than isobutylene. Thus we expect that reactions involving these two molecules Figure 6.32. Isomers of butylene

    might be quite different. However, in terms of stoichiometry, these two molecules are indistinguishable, and this means that we need to be careful in constructing the atomic matrix. For the combustion of a mixture of  ‐butylene and isobutylene, we can express the atomic matrix as

    iso

    Molecular Species  C H

    C H

    H O CO

    CO

    4

    8

    4

    8

    2

    2

    carbon

     4

    4

    0

    1

    1 

    hydrogen

    8

    8

    2

    0

    0

    oxygen

     0

    0

    1

    2

    0 

    Take CO and

    iso

    C H

    as the pivot species in order to obtain expressions for 2

    4

    8

    R

    , R

    and R

    in terms of R

    and iso

    R

    .

    C4H8

    CO

    H2O

    CO2

    C4H8

    6‐33. A complex system of optical isomers involves ortho‐cresol (

    OC

    C H O

    ),

    7

    8

    meta‐cresol (

    MC

    C H O

    ), water ( H O ), sulfuric acid ( H O

    S

    ), ortho‐cresol‐

    7

    8

    2

    2

    4

    sulfonic acid ( C H O SOCS ), and meta‐cresol sulfonic acid ( C H O

    MCS

    S

    ). Use

    7

    8

    4

    7

    8

    4

    Axiom II to develop three constraints for the net rates of production associated with these six molecular species.

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