Physico-chemical Changes in Hemicelluloses of Eucalyptus tereticornis during Sulphite Cooking of Holocellulose

Holocellulose from Eucalyptus Tereticornis were isolated by 5% potassium hydroxide, 16% potassium hydroxide and 24% potassium hydroxide + 4% boric acid in 14.8%, 84% and 5.3%, yield repectively. The main hemicellulose found to be present was xylan. Holocellulose from Eucalyptus Tereticornis was prepared and subjected to bisulphite pulping (pH 4.5-3.5 and pH 6.5-4.5) and neutral sulphite pH(8.5-6.5). Hemicellulose isolated by 5% potassium hydroxide from the residual holocellulose of sulphite cooks. Physico-chemical changes in henicelluloses were studied. It was observed that with the increase in Ph the retention of hemicellulose in residual holocellulose improved. But contrary to this, isolatable amount of hemicellulose decreased, particularly, xylan. Reasons for the same are discussed in the paper.