Making plastics from carbon dioxide: salen metal complexes as catalysts for the production of polycarbonates from epoxides and CO2.

Most synthetic polymers are made from petroleum feedstocks. Given the non-renewable nature of these materials, there is increasing interest in developing routes to polymeric materials from renewable resources. In addition, there is a growing demand for biodegradable polymeric materials. Polycarbonates made from CO(2) and epoxides have the potential to meet these goals. Since the discovery of catalysts for the copolymerization of CO(2) and epoxides in the late 1960's by Inoue, a significant amount of research has been directed toward the development of catalysts of improved activity and selectivity. Reviewed here are well-defined catalysts for epoxide-CO(2) copolymerization and related reactions.

Discrete Metal-Based Catalysts for the Copolymerization of CO2 and Epoxides: Discovery, Reactivity, Optimization, and Mechanism

Carbon dioxide is an important carbon source in the atmosphere and is “problematic” toward the activities of human beings. Although carbon dioxide is a cheap, abundant and relatively nontoxic C1 source, its chemical transformations have not been widely developed so far and are still far from synthetic applications, especially in the construction of the C–C bond. This critical review summarizes the recent advances on transition-metal-catalyzed C–C bond formation through the fixation of carbon dioxide and their synthetic applications (124 references).

Transition-metal-catalyzed C–C bond formation through the fixation of carbon dioxide

https://purehost.bath.ac.uk/ws/files/10904963/Kember_etal_manuscript_rev_5.pdf

Catalysts for CO2/epoxide copolymerisation

https://pubs.rsc.org/en/content/articlepdf/2019/gc/c8gc03086c

CO2-fixation into cyclic and polymeric carbonates: Principles and applications

A homologous series of aliphatic polycar- bonates with different side-chain lengths was synthesized by ring-opening polymerization of terminal epoxides with CO2 using zinc adipionate as catalyst (patented process of Empower Materials (formerly PAC Polymers Inc.)). Addi- tionally, a polycarbonate was made having a cyclohexane unit in its backbone, together with a terpolymer having both cyclohexane and propylene units. After characterization of thermal properties the aliphatic polycarbonates were found to be completely amorphous. Polycarbonates derived from long-chain epoxides showed a glass-transition temperature (Tg) below room temperature, whereas polycarbonates de- rived from cyclohexene oxide showed a Tg of 105°C, the highest yet reported for this class of polymers. The initial decomposition temperature of the polymers in air and ni- trogen atmospheres was found to be less than 300°C. The mechanical properties and the dynamic mechanical relax- ation behavior of the polymers were also reported. The effect of the chemical structure on the physical properties of ali- phatic polycarbonates was discussed. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1163-1176, 2003

Physical properties of aliphatic polycarbonates made from CO2 and epoxides

Aliphatic polycarbonates are a relatively new class of polymer, which are characterized by an instability at the functional group, which makes them easily degraded and capable of biodegradation; as such, they constitute a potentially powerful group of polymers for exploitation in green technology. Rheological properties in shear flow are presented for the seven following different aliphatic polycarbonate samples: polyethylene carbonate, polypropylene carbonate, linear pentene polycarbonate, linear hexene polycarbonate, linear octene polycarbonate, cyclohexene polycarbonate, copolymer of propylene oxide (20%), and cyclohexene oxide (80%), using parallel plate rheometry. No studies of the rheological properties of aliphatic polycarbonates have been reported in the literature to date. The steady-state and the dynamic properties of these new polymers are investigated, and the resulting flow curves and the dynamic relaxation spectra of the aliphatic polycarbonate melts are presented. One of the major problems encountered in trying to characterize the melt rheology and relate behavior to the underlying molecular structure is the instability of the polymers. Because of this, a narrow processing window is present for each polymer, and it makes it impossible to compare all polymers at a constant temperature or range of temperatures in the melt. Nevertheless, some progress can be made. In all cases, the rheological response is discussed in terms of molecular characteristics, in particular, the length of the side chain and the molecular weight distribution. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 534–544, 2004

Andre Gakh

Papers

Physical properties of aliphatic polycarbonates made from CO2 and epoxides

The effects of chemical structure on the shear rheology of aliphatic polycarbonates