Optimization of beech wood pulping in catalyzed acetic acid media

Fagus sylvatica wood samples were treated in HCl-catalyzed, acetic acid sol utions. The effects of selected operational variables (catalyst concentrati on, reaction time and liquor to wood ratio) on pulp yield, composition of p ulps and composition of pulping liquors were assessed using incomplete, sec ond-order, centred, factorial designs. Pulp composition was measured by the contents in cellulose, xylan and lignin. The concentrations of glucose, xy lose and furfural in pulping liquors were also considered as experimental v ariables. Under selected conditions, pulps with 5.8% to 7.5% Klason lignin (kappa numbers in the range 25 to 33), 77.2% to 85.3% cellulose and 3.3% to 6.1% xylan were obtained at 45.8% to 50.0% pulp yield. The selected pulps showed good SCAN viscosity (723 to 814 mL/g) and alkaline resistances which were affected by the acetyl group content of samples (6.6 to 7.6 weight pe rcent).