Use this URL to cite or link to this record in EThOS: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.735236
Title: Investigations on esparto cellulose
Author: Duff, Winifred
Awarding Body: University of Edinburgh
Current Institution: University of Edinburgh
Date of Award: 1948
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Abstract:
1. The fluidity of the pulp was only increased unduly if an excess of strong (greater than 12%) sodium hydroxide was used in the isolation from the grass. 2. Bleaching does not affect the fluidity if the strength of the solution does not exceed 1%, and the volume 255 c.c./lOO g. grass and the temperature is kept below 45?C. 3. Complete removal of pentosan from the cellulose was effected after a minimum of 9 hours at 401bs/sq.inch pressure with 12% sodium hydroxide solution (100 c.c./lO g. grass). 4. Xylan was isolated together with a considerable amount of ash and other impurities - the purest product was obtained after treating the grass according to L.E. Wise - dewaxing, defatting, bleaching and delignifying followeu by extraction in the cold with 5% sodium hydroxide solution. I. Similarities between esparto and Cotton Celluloses. 1) Hydrolysis to glucose in almost quantitative yield. 2) Acetolysis to cellobiose octa-acetate in comparable yields, providing evidence as to glucose units linked 1:4 as in callobiose in esparto cellulose. 3) Methylation in nitrogen gave rise to no tetramethyl glucose expected from end-groups and only 2:3:6-trmethyl glucose, evidence of the lack of branching and cross-linkages in esparto cellulose. 4) Comparable ?-cellulose contents . 5) Similar chain-lengths - average value of 1000 units. II. Differences between Esparto and Cotton Celluloses. 1) Substitution with p-toluene sulphonyl chloride reveals that the primary hydroxyls are more reactive in esparto cellulose than in cotton cellulose. 2) Oxidation with from 0.20M to 0.26M sodium periodate indicates the secondary hydroxyls on C(2) and C(3) are less reactive in esparto cellulose than in cotton cellulose. In both these latter cases the xylan is found to hinder the substitution when associated with the cellulose.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.735236  DOI: Not available
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