| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2000: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 1999: ¥2,400,000 (Direct Cost: ¥2,400,000)
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| Research Abstract |
A.Depolymerization of cellulose during the TEMPO-mediated oxidation must be controlled as possible in order to prepare water-soluble cellouronic acid (β-1, 4-linked polyglucuronic acid) having various molecular weights. Then depolymerization mechanism of cellouronic acid during the oxidation was studied under various conditions by changing combinations of the reagents added. Molecular weights of the products were determined by size exclusion chromatography using aqueous GPC columns and 0.1N NaCl as an eluent. The results showed that some radicals formed in the oxidation medium consisting of TEMPO and NaBrO during the oxidation were likely to bring about remarkable depolymerization. β-Elimination had little influence on the depolymerization.
B.The addition of t-butylphenol as a radical scavenger to the oxidation medium could avoid the depolymerization to some extent, although neither MgCl_2 nor sodium dithonite had the effect.
C.When higher molecular weight regenerated celluloses, such as hollow fibers prepared from linters by cupriammonium solutions, were used as the starting materials for the TEMPO-mediated oxidation, correspondingly higher molecular weight cellouronic acids were prepared.
D.α-Chitin, β-chitin, amylose, amylopectin, curdlan and pullulan were selectively oxidized at their C6 primary hydroxyl groups to give the corresponding water-soluble polyuronic acids quantitatively by the TEMPO-mediated oxidation.
E.Cellouronic acid was hydrolyzed to glucuronic acid by crude cellulase treatments, and thus cellouronic acid had both biodegradability and biometabolizability.
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