Batchwise production of polyethylene terephthalate from terephthalic acid

Analysis of the esterification process for poly(ethylene terephthalate)

“…If it is too small, the liquid phase fraction becomes zero. In the previous section, it was discussed that the solubility data by Yamada et al 5 are relatively small compared to those by Baranova and Kremer, 13 and even to those assumed by Ravindranath and Mashelkar. 1 Thus, with the Yamada et al's solubility data one cannot get a solution that satisfies the material balance equations having non-zero liquid phase fraction.…”

“…The equivalent concentration of TPA, η TPA S is the equivalent of carboxylic end-groups per unit mass of pure TPA. (η TPA = 12.039 ç -COOH equiv/kg TPA) , AV a ú α (when there is no undissolved TPA in the reaction mixture) β = 1 and C 1 = ζ (13) Here, α is given by the equivalent mole of carboxylic endgroup of TPA dissolved per unit mass of the liquid phase of the reaction mixture. In the following Equations, the ratio of the hydroxyl endgroup to the total end-groups, ϕ; the number average molecular weight, M n ; the number average degree of polymerization, P n ; the saponification value, SV; the degree of esterification, E s ; and the percentage of DEG based on bound TPA, d, are expressed in terms of the equivalent of carboxylic endgroups, AV, and the equivalent of hydroxyl end-groups, OHV, in the oligomers.…”