EDTA incorporated Fe-Zn double metal cyanide catalyst for the controlled synthesis of polyoxypropylene glycol

One pot, solvent free ring opening polymerization (ROP) of propylene oxide (PO) was studied by using lab synthesized heterogeneous double metal cyanide (DMC) catalyst. A series of DMC catalysts was prepared by using EDTA as novel complexing agent (CA) and characterized in detail by PXRD, FT-IR, UV–Vis, ¹³C CP-MAS NMR, AAS, SEM, XPS, and CHNS analyzer. The suitable amount of CA favored high Zn/Fe ratio and enhanced catalytic activity for polyoxypropylene glycol (PPG) synthesis. It was observed that the properties of PPG are governed by reaction parameters, including catalyst amount, reaction time, temperature, pressure, feed to initiator ratio, and different initiators. The prepared polymers have M_w (160 to 19,667 g mol⁻¹) and PDI (1.05 to 3.01) during optimization. The structure elucidation of PPG was confirmed by FT-IR, GPC, and ¹H NMR. Dipropylene glycol (DPG) initiator yielded highest 93% PPG with 1.29 PDI, and 4.9 mg-KOH g⁻¹ hydroxyl value. The kinetics study confirms first-order reaction with proposed coordination mechanism.[Figure not available: see fulltext.]