Derivatives of native lignin from softwood feedstocks
At least one embodiment of the present inventions relates to a method of producing a softwood lignin derivative softwood lignin derivative. The method includes steps of pulping a fibrous biomass, heating the biomass, maintaining the elevated temperature for 1 minute or longer, separating the cellulosic pulp to form a lignin rich material, and recovering derivatives of native lignin wherein the derivatives have an aliphatic hydroxyl content of from about 2.5 mmol/g to about 7 mmol/g. The derivatives can have a phenolic hydroxyl content of from about 2 mmol/g to about 8 mmol/g and a normalized RSI of 10 or greater. The method can be a kraft process or a modification thereof.
1. A method of producing a softwood lignin derivative softwood lignin derivative said method comprising:
a. pulping a fibrous biomass;
b. heating the biomass;
c. maintaining the elevated temperature for 1 minute or longer;
d. separating the cellulosic pulp to form a lignin rich material; and
e. recovering derivatives of native lignin wherein the derivatives have an aliphatic hydroxyl content of from 2.5 mmol/g to about 7 mmol/g, phenolic hydroxyl content of from about 2 mmol/g to about 8 mmol/g, and a normalized RSI of 10 or greater;
wherein the method is a kraft process or a modification thereof.
2. The method according to claim 1 , wherein the derivative has an aliphatic hydroxyl content of from about 2.75 mmol/g to about 5 mmol/g.
3. The method according to claim 1 , wherein the fibrous biomass comprises pine, spruce, or combinations/hybrids thereof.
4. The method according to claim 1 , wherein the fibrous biomass comprises Pinus radiata, Pinus taeda , spruce, or combinations/hybrids thereof.
5. The method according to claim 1 , wherein the lignin derivative has a normalized RSI of about 15 to about 35.
6. The method according to claim 1 , wherein the derivative has an alkoxy content of 1.4 mmol/g or less.
7. The method according to claim 1 , wherein the derivative has an alkoxy content of 0.1 mmol/g or greater.
8. The method according to claim 1 , wherein the derivative has a normalized RSI of 15 or greater.
9. The method according to claim 1 , wherein the derivative has a normalized RSI of 40 or less.