A Novel Method for Analysis of Xanthate Group Distribution in Viscoses |
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Authors: | Axel Rußler Thomas Lange Antje Potthast Thomas Rosenau Elena Berger-Nicoletti Herbert Sixta Paul Kosma |
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Institution: | 1. University of Natural Resources and Applied Life Sciences, Christian-Doppler-Laboratory and Department of Chemistry, Muthgasse 18, A – 1190 Vienna, Austria, Fax: (+43) 1 36006 6059;2. Lenzing R & D, A – 4860 Lenzing, Austria |
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Abstract: | Analytical monitoring of xanthation in the viscose process along with xanthate group analysis in the viscose material is a long-debated problem in cellulose chemistry. The task is rendered extremely intricate by the lability of the starting material and the harshness of the reaction medium, which adds to a lack of suitable analytical approaches. In a four-years' endeavor in our lab, a method is being developed which allows to analyze the distribution of xanthate groups in viscoses relative to the anhydroglucose units and along the cellulose chain. In a first step the xanthate groups are stabilized by alkylation, which was optimized towards quantitative conversion. In a second step, the remaining free hydroxyl groups are protected by carbanilation, followed by selective removal of the stabilized xanthate groups. Steps two and three thus generate an inverse image of the initial xanthate pattern. In the forth and fifth step, the liberated hydroxyl groups are methylated, and the carbanilates are removed, so that in the overall process the xanthates were replaced by methyl groups. All reaction steps have been comprehensively tested with regard to completeness of conversion and orthogonality of the protecting groups. |
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Keywords: | methylation analysis substitution pattern viscose xanthates |
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