Mixed series/parallel reactions,

Chain-growth polymerization is perhaps the most important and complex example of a mixed series/parallel reaction. For example, polystyrene is formed by adding one styrene molecule at a time to the end of a growing polymer chain. 

For the series-parallel reactions, A 4 B I C and A 3 D, find Part a)1-13 maXimUm yield of B in in plug flow, (b) in mixed flow. 

Tsai, K. and R. O. Fox (1993). PDF modeling of free-radical polymerization in an axisymmetric reactor. EES Report 254, Kansas State University, Manhattan, Kansas. (1994a). Modeling the effect of turbulent mixing on a series-parallel reaction in a tubular reactor. ICRES Report 9403, Kansas State University, Manhattan, Kansas. 

Figure 8.14 Distribution of materials in a mixed flow reactor for the elementary series-parallel reactions...

Li, K. T and Toor, H. L., Turbulent reactive mixing with a series-parallel reaction Effect of mixing on yield. AIChE. J. 32,1312 (1986). 

Li, K.T. and Toor, H.L. (1986), Turbulent reactive mixing with series parallel reaction, effect of mixing on yield,A/C/i 7.,32, 1312. 

When talking about mixed reactions (series-parallel reactions, consecutive-competitive reactions), we refer to interrelated reactions that contain subprocesses that can be regarded... 

Systems of multiple reactions usually fall into one of four categories. These classifications are parallel, independent, series, and mixed series/parallel. Recognizing the structure of a multiple-reaction system frequently helps to identify the best approach to design or analysis. 

The series byproduct reaction requires a plug-flow reactor. Thus, for the mixed parallel and series system above, if... 

Figure 2.3 Choice of reactor type for mixed parallel and series reactions when the parallel reaction has a higher order than the primary reaction.

In practice, it is often possible with stirred-tank reactors to come close to the idealized mixed-flow model, providing the fluid phase is not too viscous. For homogenous reactions, such reactors should be avoided for some types of parallel reaction systems (see Figure 5.6) and for all systems in which byproduct formation is via series reactions. 

In complex cases, series and/or parallel reactions may be going on simultaneously but, in general, the sole source of A and B are the starting materials. Neither is regenerated in the course of the reaction. The kinetics of reaction are, more or less, simply related to the concentrations of A and B. If A and B are mixed under reaction conditions, the reaction will proceed. 

A simplified mathematical description of this three-zone model proved [332], however, that the quantity of material converted in the dispersion zone could be ignored, if the original concentration ratio of A and B was less than 0.1 and the action of micro- and macro-mixing is described by the Damkohler number Da = fczCBo/s and n = 27twD/ qs) (where w is the flow rate D is the dispersion coefficient q is the liquid throughput and s [s ] is the shrinkage rate of the volume element). The model was evaluated with competitive reactions in series and parallel reactions, and was found to be adequately applicable. 

In the previous chapter, we examined series and series-parallel kinetics. The extent of mixing can have an effect on the selectivity to the various products in such reaction networks. The selectivity is the percentage of the products that are any one of the products. To compute the yield we take the product of the conversion and the selectivity. Thus the yield is a fraction of a fraction. 

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