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Environmentally Friendly, Not Just Hot Air

February 10, 2014 | A version of this story appeared in Volume 92, Issue 6

Nov. 18, 2013, page 30: A review of the book “The Enlightenment” incorrectly stated that the intellectual movement occurred from the last decade of the 16th century through the first decade of the 18th century. The period was from the last decade of the 17th century through the first decade of the 19th century.

Using carbon dioxide as a feedstock is an interesting concept. In “More Than Hot Air,” Alex Scott explains how German firms will use CO2 as a feedstock for useful chemicals. Chemical processes using CO2 at more than several 10,000 tons per year had not been revealed for many years after urea manufacturing (C&EN, Nov. 4, 2013, page 20).

I would like to introduce an environmentally friendly process using more than 100,000 tons per year of CO2 as a feedstock. The world’s first process, developed by Asahi Kasei (Japan), has already been successfully commercialized.

An aromatic polycarbonate (PC) having demand of 3.2 million tons per year for engineering plastics is widely used in our daily lives—for CDs, DVDs, headlamps, mobile phones, cameras, and more. All PC had been produced from CO as a feedstock until 2002; more than 90% had been made by the so-called phosgene process. The phosgene process must use not only highly toxic and corrosive phosgene made from CO and Cl2 but also large quantities of solvents, CH2Cl2—likely to be carcinogenic—and water.

Only the Asahi Kasei nonphosgene PC process uses CO2 instead of CO. In the solvent-free Asahi Kasei process, the outputs are just two products: high-quality PC and high-purity monoethylene glycol (MEG). The PC and MEG are produced via ethylene carbonate, dimethyl carbonate, and diphenyl carbonate.

All CO2 used is fixed into the products. The CO part makes the carbonate group of PC, and the residual O part makes one of the OH groups of MEG. The Asahi Kasei process favorably uses the CO2 by-product, which is usually emitted into the atmosphere.

Chimei-Asahi (Taiwan) successfully manufactured the world’s first PC from CO2 in 2002 under the license of Asahi Kasei. Successful commercialization has followed with four licensees: Samsung Cheil (South Korea), Lotte Chemical (South Korea), Kazanorgsintez (Russia), and Saudi Kayan (Saudi Arabia).

A total of 755,000 tons per year of high-quality PC from CO2 has been well accepted in the market, and about 130,000 tons per year of CO2 has been used as feedstock. The share of nonphosgene PC from CO2 is 16% of the world’s nominal capacity of PC and follows the big two, Bayer (26%) and SABIC (Lexan: 21%).

Details are described in “Non-Phosgene Polycarbonate from CO2: Industrialization of Green Chemical Process” (Shinsuke Fukuoka, New York: Nova Science Publishers, 2012).

Shinsuke Fukuoka
Kurashiki, Okayama, Japan



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