Page 446 - Elements of Chemical Reaction Engineering Ebook

Chap. 7 Questions and Problems 41 7

Rj + 1 kn > Pj (P7- 16.2)
(b) Show that

where
k, = k,+ k,+ k,,
(c) Neglecting solvent transfer, show that

(d) Explain how you can determine rate law parameters from expenmental
data obtained in a CSTR. Use sketches to elucidate your explanation.
(e) Typical activation energies for the initiation, propagation, and termination
steps are: 20 kUmol, 20 kJ/mol, and 9 kT/mol. Discuss the effect of tem-
perature on free-radical polymerization.
W-17B The free-radical polymerization reaction discussed in Section 7.3.3 for a batch
reactor is to be carried out in a CSTR and a PFR.
(a) Plot the effluent initiator and monomer concentrations as a function of
the space-time T.
(b) Compare your results for two equal-sized CSTRs in series with one
CSTR. The total volume is the same in both cases.
(c) Vary the parameter values (Le., b, k,) and discuss your results.

Additional information:
Mo = 3 mol/dm3 I20 = 0.01 mol/dm3
b = s-l kp = 10 dm3/mol-s kf = 5 X IO7 dm3/mol.s
W-lfiA (Anionic polymerization)
(a) Determine the final number-average and weight-average chain lengths
and molecular weights along with the extent of polymerization and poly-
dispersity in an anionic polymerization for an initial monomer concentra-
tion of 2 M and for initiator concentrations of 1, 0.01, and 0.0001 Ai.
(b) Calculate the radical concentration and polymer concentration as a func-
tion of time for j = 3, 7, 10 for the same monomer and initiator concen-
trations. k, = w, k, = 100 dm3/mol.s
(c) Repeat (b) for the case
r, = k, [A-] M
and

with k, = 10 dm3/mol.s and K, = lo-* moi/dm3.
W-19, An anionic polymerization is to be carried out in a CSTR. The reaction steps are
k,
I+M ___) R,
R,+M kp > R,,,