DMAP/Cr(III) Catalyst Ratio: The Decisive Factor for Poly(propylene carbonate) Formation in the Coupling of CO₂ and Propylene Oxide

Abstract

Highly efficient formation of poly(propylene carbonate) can be achieved in the coupling of CO2 and propylene oxide assisted by 4‐(N,N‐dimethylamino)pyridine (DMAP) and catalyzed with salen chromium(III) chloride by using DMAP/Cr ratios of less than 2. Under these conditions a possible backbiting mechanism is suppressed, leading to only minor amounts of cyclic carbonate as a side product. magnified image

Alternating Copolymerization of Carbon Dioxide and Cyclohexene Oxide and Their Terpolymerization with Lactide Catalyzed by Zinc Complexes of N,N Ligands

“…[5] Over the last decade the use of homogeneous catalysts has lead to a drastic increase in catalytic activities. [6][7][8] For the copolymerization of CO 2 and propylene oxide, salen complexes, especially of chromium [9,10] and cobalt [11][12][13] have come into focus. Yet, the highest activities for the alternating copolymerization of CO 2 and cyclohexene oxide so far have been reached by Coates' bdiketiminato (BDI) zinc complexes (see below).…”

Synthesis and Electrochemistry of Schiff Base Cobalt(III) Complexes and Their Catalytic Activity for Copolymerization of Epoxide and Carbon Dioxide

“…[21] Especially, binary catalytic system of many forms of the (salen)Co(III)/ Lewis base as catalysts is widely used in the fixation of CO 2 with epoxide to form polycarbonates. [22][23][24][25][26] Recent studies have focused on how to improve the efficiency of the copolymerization and to enhance the catalytic activity of these complexes. [22,24,25,[27][28][29][30] In this paper, we describe the electrochemical properties of several structurally related cobalt complexes and the X-ray crystal structure, which provided an important insight into the copolymerization mechanism of CO 2 and propylene oxide catalyzed by these complexes.…”

Alternating copolymerization of CO2 with propylene oxide and terpolymerization with aliphatic epoxides by bifunctional cobalt Salen complex

“…After the pioneering work by Inoue and co-workers 5,6 in the late 1960s, a wide variety of metal catalysts were developed for this transformation. [7][8][9][10][11][12][13][14][15][16][17][18] Among the metal complex catalysts, Co Schiff base complexes are effective catalysts for CO 2 / epoxides coupling reactions, 11,13,[15][16][17] because these complexes can control the molecular weights and distribution of the polycarbonates produced and regulate the selective formation of alternating copolymers. However, Co Schiff base complexes are not highly active at a high monomer/catalyst mole ratio in conjunction with a Lewis base or organic salt, which prevents them from becoming commercially viable.…”