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This paper focuses on the world's first nonphosgene process using CO 2 as starting material succeeded in development and industrialization by Asahi Kasei Corp. The Asahi Kasei Process enables high-yield production of high-quality PC having excellent properties and high-purity monoethylene glycol (MEG), starting from ethylene oxide (EO), by-produced CO 2 and bisphenol-A without waste and waste water. The innovative reactive distillation technologies in the monomer production and the innovative gravity-utilized, non-agitation polymerization reactor in the melt polymerization, led the new process to success. The monomer process consists of 3 production steps, ethylene carbonate (EC) from CO 2 and EO, dimethyl carbonate (DMC) and MEG from EC and MeOH, and diphenyl carbonate (DPC) and MeOH from DMC and PhOH. All intermediates are recycled. The new type polymerization reactor perfectly overcomes the difficulty based on the extremely high viscosity in the melt polymerization of DPC with Bis-A. The by-produced PhOH is recycled to the monomer process. The reduction of CO 2 emissions (0.173t/ PC 1t) is also achieved, because CO 2 used as raw material is utilized as the main chain components of the products. Four commercial plants (Taiwan: 150,000 t/y, Korea: 2 plants of 65,000 t/y, Russia: 65,000 t/y) using the Asahi Kasei Process are now successfully operating, and the plant of 260,000 t/y in Saudi Arabia will start in 2010.

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.

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High molecular weight aromatic polyetherketone (PEK) was found to react with 4,4′‐difluorobenzophenone (DFB) in the presence of potassium carbonate in benzophenone or diphenyl sulfone at 300°C, yielding low molecular weight PEK with fluorophenyl end groups, while neither polyetheretherketone (PEEK) nor poly‐thioetheretherketoneketone was found to react under similar conditions. Reaction model experiments showed that 4‐fluoroben‐zophenone reacts with potassium carbonate at 300°C to yield benzoyldiphenyl ether and that benzoyldiphenyl ether undergoes spontaneous trans‐etherification in the presence of potassium carbonate at 300°C. These results indicate that the overall reaction yielding PEK of reduced molecular weight consists essentially of DFB oligomerization followed by trans‐etherification between the DFB oligomer and PEK. © 1993 John Wiley & Sons, Inc.

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