| Research Abstract |
Derivatives of cellulose and starch substituted with long chains having a carboxyl group at their ends have not been prepared. Such derivatives were thought by us to produce gel by entrapping water through the formation of hydrogen bonds and/or the formation of salts between carboxyl groups with multivalent metal ions. With the aim of preparing one of these derivatives, methylcellulose was subjected to hydroxyethyllation with ethylene oxide followed by carboxymethylation. Although these reactions were proved to occur, degradation also was found to occur severely and no gelation expected by the addition of ions of metals such as calcium, magnesium and barium could not be observed. Secondary, hydroxyethylcellulose of MS 2.27 and its further hydroxyethylated one were subjected to TEMPO oxidation, which oxidizes a primary alcohol group to a carboxyl group selectively. As expected, products rich in carboxyl groups were obtained, but they did not produce gel except aluminium ion, which gave suspended matter. In the preceding two experiments no information was obtained as to the length of substituents. Then next, the introduction of a substituent which consists of nine carbon and has a carboxyl group, was attempted by successive treatment of methylcellulose and hydroxyethylcellulose with oleyl chloride and with a mixture of potassium permanganate and sodium periodate. Oleylation occurred successfully, but cleavage of double bonds was accompanied by removal of oleyl ester groups. even under neutral oxidation conditions Thus, no aimed products were obtained. Finally, gel containing carboxyl groups was prepared from hydroxyethylcellulose and methylcellulose by grafting acrylamide followed by alkali hydrolysis or Hoffman degradation.
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