| 摘要 |
A method for forming II-type cellulose, which comprises introducing together a slurry having water and a I-type cellulose dispersed therein and water in the state of high temperature and high pressure to a tubular reactor (28) contacting the I-type cellulose with a hot water in a supercritical state or subcritical state for a predetermined time in the tubular reactor (28), to thereby cleave a part of the hydrogen bonds in the I-type cellulose and dissolve the I-type cellulose into the water in a supercritical state or subcritical state, cooling a cellulose solution discharged from the tubular reactor (28) in a cooler (30) to room temperature or lower, followed by allowing to stand, to thereby precipitate crystals of II-type cellulose having a molecular weight lower than that of the I-type cellulose, and separating the resultant II-type cellulose from a solvent. The method allows the preparation of pure II-type cellulose by the use of a simple process.
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