Effect of temperature on the soda and kraft cooking of corn stalks

Abstract

SynopsisThis study included soda and kraft process of corn stalks at constant active alkali, the kraft liquor having 25% sulfidity. Five cookings were made at different temperatures, 80,120,140, 160, and 180"C, each for 1 h. Under the condition of the study the following temperature effects were noted: (1) Delignification could be approximated by a first-order reaction. (2) The kraft process exhibited twice the rate of lignin removal as the soda of the same digestion temperature. (3) The rate of removal of carbohydrates in the kraft process is faster than soda process due to presence of sulfide ion. (4) The carbon content of thiolignin increased hydrogen and oxygen content decreased while in soda lignin the opposite occurs. (5) The amount of phenolic OH increased with increasing the cooking temperature and was more noticeable in thiolignins than in soda lignins. (6) Demethoxylation occurs in kraft cooking at elevated temperature rather than soda cooking.

Lignin-First Integrated Steam Explosion Process for Green Wood Adhesive Application

“…The oven-dried SE treated biomass (25 g) were treated with a solution of NaOH (1% by w) for 2 h at 80 °C with the liquid/solid ratio of 10/1 (by vol) to obtain the AL fractions without any dramatic chemical modification on their structures under mild conditions. , The lignin samples were labeled as w1-AL, w2-AL, a1-AL, and a2-AL, respectively, to previous SE treatments. After alkaline pulping treatment, the pulp was separated by filtration.…”

“…to obtain AL fractions without any dramatic chemical modification on their structures under mild condition. 26,27 The lignin samples were labeled as w1-AL, w2-AL, a1-AL and a2-AL respectively to previous SE treatments. After alkaline pulping treatment, the pulp was separated by filtration.…”