Effects of addition mode on Zn –Co double metal cyanide catalyst for synthesis of oligo(propylene‐carbonate) diols

Effects of dropping mode on Zn –Co double metal cyanide (DMC) catalyst are investigated using three different dropping methods. The factors that affect crystalline state are summarized and a flower‐like morphology is observed which endows the DMC catalyst with a large surface area. In copolymerization reaction, appropriate O/ Zn value is beneficial to suppress the formation of by‐product. And a catalyst with excellent catalytic performance is prepared by an improved parallel‐flow dropping method. Zn –Co double metal cyanide (DMC) complexes are promising catalytic systems for copolymerization of epoxide and CO2. In the work reported, Zn –Co DMC catalysts were prepared by parallel‐flow dropping, forward dropping and reverse dropping methods, aiming to provide an insight into the effect of addition mode on catalyst structure and catalytic performance. Catalytic properties were evaluated using the copolymerization reaction of prop ylene oxide (PO) and CO2 in the presence of chain transfer agent. The results indicated that the factors that affect crystalline state are different for different modes. And excess zinc chloride is the prerequisite for organic ligands to be retained in the catalyst and affect the structure. In addition, a catalyst with flower ‐like morphology was obtained with the parallel‐flow dropping method which provided larger surface area. An appropriate O/Zn value ensured abundant active PO which would suppress the backbiting process by forming ...

Source: Applied Organometallic Chemistry - October 23, 2018 Category: Chemistry Authors: Na An, Qifeng Li, Ning Yin, Maoqing Kang, Junwei Wang Tags: FULL PAPER Source Type: research