GU Xueping, TIAN Lulu, FENG Lianfang, et al. Thermodynamic modeling with new UNIFAC groups for solubility of nylon66-salt in water system[J]. CIESC Journal, 2016, (2): 435-441.
GU Xueping, TIAN Lulu, FENG Lianfang, et al. Thermodynamic modeling with new UNIFAC groups for solubility of nylon66-salt in water system[J]. CIESC Journal, 2016, (2): 435-441.DOI: 10.11949/j.issn.0438-1157.20151235.
Modeling of PA66 polymerization process requires accurate solubility computation of nylon66-salt in water system. The UNIFAC activity coefficient method with new groups was applied to predict the solubility. The new groups were -CH2COO-·+H3NCH2- and -CH2COOH
which characterized the component's special structure. The pure parameters of new UNIFAC groups and interaction parameters between new groups were obtained by regression with melting point and molar fusion enthalpy of PA66-salt as well as the solubility data of PA66-salt in water obtained by experiments. The UNIFAC model with new groups was used to simulate the solubility of PA66-salt in aqueous solution
giving a relative error of 2.1% from the experimental data. The model was further employed to simulate the concentration of PA66-salt under the industrial conditions (120℃) and gave a relative error as low as 5%
compared with 20% from the UNIFAC model with default groups in Aspen.