Continuous production of biodiesel from waste cooking oil in a reactive distillation column catalyzed by solid heteropolyacid: Optimization using response surface methodology (RSM)

► RD can has several advantages over conventional production of biodiesel. ► H3PW12O40·6H2O as a catalyst alleviates the neutralization problem. ► This process is environmentally friendly. ► RSM based on CCD was used to design the experiment and analyzed operating parameters.