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. It was found that the intermediates (primarily K-phthalates) formed from the dissociation of K-benzoate over a CdCl₂ catalyst reacted with K-terephthalate in an
autocatalytic reaction step A→k1R→K2SSeriesR + S→k32SAutocatalytic 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 410°C are k₁ = 1.08 × 10^–3 s^–1 with E₁ = 42.6 kcal/mol, k₂ = 1.19 × 10^–3 s^–1 with E₂ = 48.6 kcal/mol, and k₃ = 1.59 × 10^–3 dm³/mol · s with E₃ = 32 kcal/mol.
a. Plot and analyze the concentrations of A, R, and S as a function of time in a batch reactor at 410°C, noting when the maximum in R occurs.
b. Repeat (a) for temperatures of 430°C and 390°C.
c. What would be the exit concentrations from a CSTR operated at 410°C and a space time of 1200 s?