Double metal cyanide complexes synthesized by solvent‐free grinding method for copolymerization of CO₂ and propylene oxide

Abstract

Two active double metal cyanide (DMC) complexes were successfully synthesized by solvent-free grinding method. Their structures were characterized by FTIR spectrometer and X-ray diffractometer. The results showed that Complex 1 (double metal cyanide complex with K 3 Fe(CN) 6 and ZnCl 2 ) and Complex 2 (double metal cyanide complex with K 3 Fe(CN) 6 and Zn(CH 3 COO) 2 ) had the same structures, crystal forms, and lower crystallinity as both of them synthesized by conventional solvent-based methods, respectively. Investigations on grinding conditions indicated that Complex 1 ground 14 min at a high grinding strength could achieve low crystallinity and showed substantially amorphous structures. Two speculated structures of DMC were given. The alternating copolymerization of CO 2 and propylene oxide with Complex 1 as catalyst obtained anticipated poly(propylene carbonate) (PPC) with very high catalytic activity. The PPC produced by optimized Complex 1 has molecular weight (M n ) up to 98,000 and narrow polydispersity of 1.93 with more than 90% carbonate linkages. Compared with Complex 1, Complex 2 displayed low catalytic activity but high selectivity mainly due to the electron atmosphere and strong steric hindrance. V C 2011Wiley Periodicals, Inc. J Appl Polym Sci 123: [977][978][979][980][981][982][983][984][985] 2012

Layered Zn2[Co(CN)6](CH3COO) double metal cyanide: a two-dimensional DMC phase with excellent catalytic performance

“…It should be noted that the powder pattern reported by Zhang et al 53 of a DMC obtained by ball milling K 3 [Fe(CN) 6 ] and zinc acetate (complex 2 in ref. 53) is qualitatively similar to the diffraction pattern of L-DMC. We therefore suggest that the structure they observed during ball milling is an Fe(CN) 6 analogue of our layered phase.…”

Double metal cyanide catalyst prepared using H3Co(CN)6for high carbonate fraction and molecular weight control in carbon dioxide/propylene oxide copolymerization

“…We demonstrated that the carbonate fraction could be increased up to 64% by employing a dual catalytic system composed of a DMC and a Salen‐cobalt(III) complex . In this work, we report the simple preparation of a new type of DMC catalyst, which exhibits a high CO 2 incorporation (up to 67 mol %) and thus provides a successful derivatization of the conventional DMC catalyst …”

Synthesis of Zn–Fe double metal cyanide complexes with imidazolium-based ionic liquid cocatalysts via ball milling for copolymerization of CO2 and propylene oxide

“…In this regard, the simple and efficient process of mechanochemistry has proven to be effective in activating the copolymerization of CO 2 and epoxides. [28][29][30][31] Catalysts can be synthesized for polycarbonates using a metal complex. They can also be used together with a cocatalyst to enhance their performance in a binary catalyst system.…”