A preliminary study on low and medium temperature uncatalyzed and acid catalyzed organosolv pulping of poplar wood (Populus tremula L.) - I. Low temperature pulping

The present study discusses uncatalyzed and acid catalyzed organosolv pulpi ng of popular wood carried out at a temperature of 140 degrees. A mixture o f methanol-water was used as a liquor (52:48 % v/v). For catalysed delignif ications, 0.01 M H2SO4, 0.02 M HNO3 and 0.015 M (COOH)(2) solutions in the same solvent were used. The effect of the corresponding esters did not diff er much from that of the acids. A partial delignification of chips with whi te-rot fungus Coriolum versicolor prior to uncatalyzed, pulping improved th e pulp properties. A 23% loss of cellulose due to chips biodegradation excl uded this pretreatment from further experiments. Similarly, the application of peracetic acid solutions did not improve the pulp properties adequately . A comparison of the pulps properties obtained from catalysed pulpings poi nted out the highest delignification efficiency of 0.02 M solution of HNO3, given by the highest hydroxonium ions concentration in a liquor. The appli cation of 0.01 M sulphuric and 0.015 M oxalic acids solutions yielded pulps with similar parameters, the oxalic acid solution causing only moderate dr op in the DP pulps. The presumed additional effect of the added agents, pos sessing oxidizing or reducing properties, on the delignification and recond ensation of lignin, as well, was neither confirmed nor refuted. Uncatalyzed organosolv pulping conducted in a period of 0-5 hours did not provide pulp s with satisfactory parameters.