Development of RSMStatisticalModel for Methanol Carbonylation Rate for Acetic Acid Synthesis byUsing Cativa TM Technology

摘要

In recently developed Cativa~(TM) process, acetic acid is produced by methanol carbonylation reaction in which a complex interaction among all themajor reaction species including iridium, ruthenium,methyl acetate,methyl iodide and water are observed. In this study, a statistical technique of response surface method (RSM) (which is called historical data design algorithm) is applied to investigate the concentration efects of these species on the carbonylation reaction rate. A quartic equation is ftted to the experimental data, and its suitability is exam-ined by several statistical tests. Lack of ft, model F-value, coeficient of determination (R2), adjusted R-squared (Adj.R2) and predicted R-squared (Pre. R2) are respectively equal to 1.65, 182.73, 0.9822, 0.9768 and 0.9263. The validation of the proposed model is investigated by numerical optimization of the design-expert software. The desirability value of the model prediction is 0.94 that indicates the high agreement between the model pre-diction and the experimental results. The individual and binary efects of the considered parameters on the carbonylation rate are also investigated through the developed model. The steep slope/ curvature of Ir, Ru and water concentrations in perturbation plot indicates the high sensitivity of carbonylation rate to these species. The interaction efects of Ru and water on carbonylation rate show that at water concentration of 7w/w%, a steep increase occurs in the reaction rate by increasing Ru promoter. Investigating the simultaneous efects of Ru and Ir concentrations on the carbonylation rate indicates that the increase of Ru to Ir molar ratio promotes the reaction rate by enhancing the lability of [Ir(CO)2I3Me]-complex and preventing the production of inactive species of [Ir(CO)2I4]-in the catalytic cycle.