The Effect of the Duration of Alkali Treatment on the Solubility of Polyoses

Authors: MUALLA BALABAN, GÜNEŞ UÇAR

Abstract: Holocelluloses from the wood of pine and oak species growing naturally in Turkey were extracted with 5% KOH solution under specified conditions, and soluble polyoses and lignin were examined. The extractions of both pine and oak wood holocelluloses followed the mechanism of second order reaction. While the glucomannan of pine was poorly dissolvable during the extraction, xylan, the main polyose of hardwoods, was removed very efficiently upto almost 90 %. The solubility of xylane also obeyed the some kinehes. By the equation [ A ] 1- n - [ A 0 ] 1-n = ( n-1) kt, where n=2, for the second order mechanism, kinetic parameters [A O ] and k were calculated to be 29.55%, 0.04417 for pine and 44.675%, 0,03018 for oak. Using these kinetic parameters, the predicted yields were in very close agreement with their counterparts from the experiments. Moreover, the holocelluloses and certain residues obtained after alkali were analyzed with regard to their anhydromonosaccharides. GalactOĞLUcomannan, the main polyose of pine wood, was resistant to alkali, and about half of the more easily soluble arabinoxylane was removable. In contrast to mannane, nearly 90% of the hard wood xylane was dissolved by alkali, and its extraction also followed the second order mechanism. Thereafter, the kinetic parameters related to this extraction were calculated.

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