Industrialization and Expansion of Green Sustainable Chemical Process: A Review of Non-phosgene Polycarbonate from CO₂

Abstract

The world's first non-phosgene polycarbonate process from CO 2 has been developed and industrialized by Asahi Kasei Corporation (Japan). Hitherto, all polycarbonates (PCs) have been produced using CO as a raw material. Among them, most PCs have been produced by so-called the "phosgene process" using highly toxic phosgene (COCl 2 ) and large amounts of solvents (probable human carcinogen CH 2 Cl 2 and water). The phosgene process has many environmental and safety problems. However, technological barriers have hindered realizing the non-phosgene PC process. The Asahi Kasei Process has not only solved the problems of the phosgene process but also contributed to sustainability (reduction of CO 2 emission, materials saving, and energy saving). High-quality PC and high-purity monoethylene glycol (MEG) are produced in high yields, respectively, without waste and wastewater, starting from CO 2 , ethylene oxide (EO), and bisphenol A (BPA). In the monomer (diphenyl carbonate: DPC) production process, innovative reactive distillation process, and in the melt polymerization process, a gravityutilized non-agitation reactor had been developed, respectively. The Asahi Kasei Process has been expanding worldwide, and 1.07 million tons of PC will be produced in 2019. The Green Sustainable Chemical Process has been changing the PC production world. In this review, the Asahi Kasei Process and perspective of the present PC production processes together with discriminating and detailed comparisons are described.

Carbon dioxide copolymers: Emerging sustainable materials for versatile applications

“…159 Aromatic polycarbonates, poly(urea)s, polyesters with novel structure can also be prepared via CO 2 -sourced intermediate such as carbonates and lactones. [160][161][162] A commercialized example is the phosgene-free bis-phenol A polycarbonate production developed by Asahi Kasei. 163 The process involves several steps sequenced by, (i) cycloaddition of CO 2 and ethylene oxide to form ethylene carbonate, (ii) formation of dimethyl carbonate from ethylene carbonate and methanol, (iii) transcarbonation by phenol to afford diphenyl carbonate, and (iv) final reaction with bisphenol A to afford the final polycarbonate.…”

Direct dimethyl carbonate synthesis from CO2 and methanol catalyzed by CeO2 and assisted by 2-cyanopyridine: a cradle-to-gate greenhouse gas emission study

“…The use of DMC as a carbonyl source substitutes the use of toxic phosgene in PC production. 12 In addition to carbonates, carbamate and urea synthesis from CO 2 with the same catalytic system has also been established. 32,[48][49][50] Such CO 2 conversions to chemicals for durable material production can be regarded by society as CO 2 sequestration.…”

“…11 DMC is an alternative carbonyl source to phosgene for producing diphenyl carbonate which is a precursor of mass-consumed polycarbonates. 12 Historically, DMC itself has been produced from phosgene although the replacement of this route has been proceeding. 6,11,13 Accordingly, many DMC synthesis routes have been investigated so far 13 including CO 2 -utilizing routes which satisfy multiple principles of green chemistry.…”

Regioselective synthesis, isomerisation, in vitro oestrogenic activity, and copolymerisation of bisguaiacol F (BGF) isomers

“…Asahi Kasei Process) still the vast majority of current PC production is phosgene-based (∼83% in 2016). 42,43 Moreover, Schotten-Baumann conditions in concert with highly reactive (tri)phosgene facilitate to study possible differences in monomer reactivity, without resorting to high temperature and deep vacuum to favour the reversible transesterification equilibrium (cf. melt polymerisation with diphenyl carbonate).…”