| Autor: |
Wade, Ricardo H., Welch, Clark M. |
| Zdroj: |
Textile Research Journal; Oct1965, Vol. 35 Issue 10, p930-934, 5p |
| Abstrakt: |
The preparation of fibrous benzyl cellulose having a D.S. of 0.5-1.7 has been studied. Cotton yarn was reacted with benzyl chloride in the presence of alkali metal hydroxides under various conditions. A process was developed in which yarn could be benzylated to a D.S. of 0.6 within 30 min, while retaining 100% to 120% of the breaking strength and 315% to 345% of the elongation of untreated yarn.The order of effectiveness of alkali metal hydroxides in activating cotton for benzyla tion was found to be CsOH > RbOH > KOH > NaOH > LiOH, contrary to earlier reports. The rate of benzylation was increased by a factor of 2-4 in going from lithium or sodium hydroxides to potassium, rubidium or cesium hydroxides. This order is the same as the known order of effectiveness of the alkali hydroxides in converting cellulose to cellulosate ions, but is opposite to the relative degree of swelling they produce. It is concluded that benzylation of cotton proceeds by an SN2 type displacement of chloride by cellulosate ions. The primary function of the alkali is to convert cellulose to cellulosate ions, and swelling of the cellulose is of secondary importance. [ABSTRACT FROM PUBLISHER] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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