Polymerization of propylene with Ziegler–Natta catalyst: optimization of operating conditions by response surface methodology (RSM)

Optimization of operational conditions for the polymerization of propylene with Ziegler–Natta catalyst was carried out via RSM. Response surface methodology (RSM) based on a three-level, four-variable Box–Behnken design was used to evaluate the interactive effects of reaction conditions such as reaction temperature (60–80 °C), monomer pressure (5–8 bar), hydrogen volume (130–170 mL), and cocatalyst to catalyst ratio (Al/Ti, 340–500) on the catalyst activity and melt flow rate (MFR). The optimum reaction conditions derived via RSM were: temperature 70 °C, pressure 8 bar, hydrogen volume 151 mL, and cocatalyst to catalyst ratio 390. The experimental catalyst activity and MFR were 8 g polypropylene/mg catalyst and 10.9 g/10 min, respectively, under optimum conditions. Optimum values were determined from process cost point of view and offered better operational conditions.