The wood chips were pulped with a kraft cooking process
under the following reaction conditions: active alkali
charge 21.3 % (as NaOH); sulfidity index 30 %; liquor/
wood ratio 4/1; time to temperature 90 min; time at temperature
(160 C) 90 min. Experiments were carried out
with 25 g (oven dry) of wood, using 200 mL rotary
digesters immersed into a thermostatic polyethyleneglycol
bath.