| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a practical process for producing polyguluronic acid. SOLUTION: At first, alginic acid is dissolved in water by neutralization with lithium hydroxide to prepare a solution containing >=5 wt.% of alginic acid. Second, the alginic acid is oxidized by adding an amount lower than a stoichiometrical amount of periodic acid or periodate. Third, the oxidation reaction is finished so as the free iodine to be separated from the reaction mixture. Forth, the free iodine is separated. Fifth, the reaction mixture is acidified and heated to obtain a component containing polyguluronic acid having smaller molecular weight. Sixth, pH of the reaction mixture is adjusted so as polyguluronic acid to be selectively precipitated. Finally, polyguluronic acid is separated by a usual method. The resultant polyguluronic acid has <20 polymerization degree and contains <8 wt.% of mannuronic acid recognized by NMR.</p> |
