Studies on the Hydrotropie Cooking

Abstract

I prepared hydrotropic pulps (HP) and neutral semichemical pulps (NSCP) from Japanese red pine (Pinus densiflora) and Japanese oak (Quercus serrata).
The results are as follows.
1. There are no difference in four excellent hydrotropic reagents for cooking (H). So, xylensulfonic soda shall be used as it is the most inexpensive.
2. As the concentrations are 25% or less, cooking abilities of H are markedly dropped. They are fairly increased as the concentrations of H are increased from 35% to 45%. But, as the parts of 45% reagents are deposited at room temperature, 35% reagents shall be generally used.
3. The chips of 1mm x 3mm x 3mm are superoir than the wood powders for the cooking samples.
4. Japaneses red pine cannot be cooked by H. Lignins of the cooked materials by H are much than those of original samples inspite of using of any kinds and any concentrations of H. Longer the cooking times are, higher the lignins of cooked materials and less holocelluloses of them will be.
5. Japanese oak can be cooked by H, but the cooked materials having less than 5 to 10% lignin will not be able to obtain. Longer the cooking times over this lignin content are, reversely lignin of cooked materials increase rapidly and holocellulose of them decrease distinctly.
6. The same yields of cooked materials will be obtained at the temperature of 150 to 180°C in the same lignin, content.
7. Using Japanese oak, the yields of NSCP are 71% and those of HP are 55% in the same lignin content of 10%.
8. Therefore, hemicelluloses of much quantities shall be dissolved into the liquor of H, and the wased liquor of H cannot be reconverted to original liquor by such dilutions, filtrations and concentrations as Mckee's theses.
9. Two step cooking process including prehydrolysis of H cannot be completely considered economically.