The structure and composition of alkali lignin, CEL, and MWL from valonea of Quercus variabilis Blume were compared by Yang et al.
 compared four lignins produced from valonea of Quercus variabilis, namely, ethanol lignin, alkali lignin, MWL, and enzyme hydrolysis lignin (EHL).
A standard curve was generated with alkali lignin
Because the alkali lignin macromolecules are curled and the reactive groups can hardly be effectively used, they need to be modified before reacting.
After Mannich reaction, the alkali lignin has more active groups that are conducive to the followed reactions.
Put the alkali lignin (We call this kind of unmodified lignin OL.) and diethanolamine into a 250 mL four-neck round-bottom flask equipped with a thermometer and mechanical stirrer.
A model solution of lignin was prepared using alkali lignin
For the present research, a model solution of lignin was prepared using alkali lignin. The alkali lignin (Aldrich Co.) was dissolved in 300 mL of distilled water.
Figure 6 depicts the behaviour of the alkali lignin concentration and COD removal during the WO experiments at different oxygen partial pressures.
A portion of the difference for acetyl bromide lignin concentrations between the two studies may have resulted from the use of an isolated maize lignin as the calibration standard in the current study and use of a commercial alkali lignin by the preceding study (see discussion below).
Saxena and Stotzky (2001) used a commercial alkali lignin as their standard (G.