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Reactions
of Synthetic Rubbers in Supercritical Water
Masaru NAKAHARA
Solution and Interface Chemistry, Institute for Chemical Research, Kyoto
University, Kyoto
Nippon Gomu Kyokaishi,(2004),77(10),365-371 General Review in Japanese
Abstract
This review on supercritical water reactions
of rubbers is composed of the following chapters: 1) Introduction,
2) Synthetic Processes in Hot and Supercritical Water Complementary
to Photosynthesis, 3) What Is Supercritical Water? 4) Rate-Controlling
Factors of Supercritical Water Reactions, 5) Chemical Bonds Composing
Rubbers and Their Reactivity, 6) Reactions of Synthetic Rubbers Studied
in Supercritical Water, and 7) Future Problems. The importance of
the development of science and technology of supercritical water reactions
are emphasized in relation to green chemistry. It is shown that hydrothermal
reactions of used rubbers and other organics is investigated in order
to conserve chemical bonds, such as C-C, C-H etc. contained in rubbers,
instead of their oxidative degradation by burning. Learning from chemical
evolution on the primitive earth, thus we hope that hydrothermal synthesis
can replace photosynthesis as much as possible to avoid the energy
crisis of the 21st century. For recycling styrene-butadiene and ethylene-propylene
rubbers, several works have been carried out in sub- and supercritical
water. Used rubbers can be converted to useful organic compounds.
Ethylene-propylene rubbers are cracked to paraffin oils, while styrene-butadiene
rubbers are transformed into benzene and its derivatives.
Keywords:
Supercritical Water, Rubber, Green Chemistry, Bond Conservation
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