New process for producing polycarbonate

New Process for Producing Polycarbonate Without Phosgene and Methylene Chloride... 

K. Komiya, S. Kukuoka, M. Aminaka, K. Hasegawa, H. Hachiya, H. Okamoto, T. Watanabe, H. Yoneda, I. Fukawa and T. Dozone, New process for producing polycarbonate without phosphene and methylene chloride . In Green Chemistry Designing Chemistry for the environment, P.T. Anastas and T.C. Williamson, eds., American Chemical Society Symposium Series, No. 626 (ed. ), American Chemical Society, 1996, pp. 1-17. 

Asahi Chemical Industry Co., Ltd. has succeeded in developing alternative and innovative non-phosgene processes for producing isocyanates and polycaihonates in the pilot scales which are commercially viable. In the production of isocyanates, processes for both aromatic isocyanates, such as methylene diphenyl diisocyanate (MDI), and aliphatic isocyanates, such as hexamethylene diisocyanate (HDI) or isophoione diisocyanate (IPDI), have already been developed successfully. A part of those processes has already been reported (i), and the others will be reported in the near future. In this paper, the new iimovative process for producing polycarbonates is reported. 

Polycarbonates were earlier prepared by the polymerisation of phenols (e.g., bisphenol-A) using phosgene and methylene chloride. A new process has been developed by Asahi Chemical Industries using solid state polymerisation for producing polycarbonate without phosgene and methylene chloride. ... 

Among these processes, only the Hock process and the toluene oxidation are important industrially. The other processes were discarded for economic reasons. In the Hock process acetone is formed as a by-product. This has not, however, hindered the expansion of this process, because there is a market for acetone. New plants predominantly use the cumene process. More than 95% of the 4,691,000 my (m = metric tonnes) consumed is produced by the cumene peroxidation process. Phenol s consumption growth rate of 3% is primarily based on its use in engineering plastics such as polycarbonates, polyetherimide and poly(phenylene oxide), and epoxy resins for the electronic industry. The Mitsui Company is, for instance, the world s second largest producer of phenol. Japan s production... 

Microcellular polymers are closed cell thermoplastics produced by gas nucleation. They have a high number of very small cells with a diameter of 10 pm, and bubble densities in excess of 100 million per cm. First produced in the early 1980s with the objective of reducing the amount of polymer used in mass produced items, these novel materials have the potential to revolutionise the way thermoplastic polymers are used today. PVC, PS, polycarbonate (PC), polyethylene terephthalate (PET) and not only these polymers can be applied for such kinds of products. As no harmful chemicals are used in the microcellular technology, it is likely that these new products will replace many types of foam now produced by processes that damage the environment [59]. 

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