Terephthalic acid (TPA) finds extensive use in the manufacture of synthetic fibers (e.g.,...

Terephthalic acid (TPA) finds extensive use in the manufacture of synthetic fibers (e.g., Dacron) and as an intermediate for polyester films (e.g., Mylar).

The formation of potassium terephthalate from potassium benzoate was studied using a tubular reactor [Ind. Eng. Che111. Res., 26, 1691 (1987)].

It was found that the intermediates (primarily K-phthalates) formed from the dissociation of K-benzoate over a CdCI2 catalyst reacted with K-terephthalate in an autocatalytic reaction step.

where A = K-benzoate, R = lumped intermediates (K-phthalates, K-isophthalates, and K-benzenecarboxylates), and S = K-terephthalate. Pure A is charged to the reactor at a pressure of 110 kPa. The specific reaction rates at 410̊ C are k1 = 1.08 x 10-3 s-1 with E1 = 42.6 kcal/mol, k2 = 1.19 x 10-3 s-1 with E2 = 48.6 kcal/mol, k3 = 1.59 x 10-3 dm3/mol • s with E3 = 32 kcal/mol.

(a) Plot the concentrations of A, R, and S as a function of time in a batch reactor at 410̊ C noting when the maximum in R occurs.

(b) Repeat (a) for temperatures of 430̊ Cand 390̊ C.

(c) What would be the exit concentrations from a CSTR operated at 410̊ C and a space time of 1200 s?