Processes for recovery of derivatives of native lignin
The present disclosure relates to processes for recovery of derivatives of native lignin from lignocellulosic feedstocks wherein the derivatives have a certain aliphatic hydroxyl content. Surprisingly, it has been found that stable and predictable antioxidant activity is provided by selecting for derivatives of native lignin having a certain aliphatic hydroxyl content.
1. A process for recovering a lignin derivative from a hardwood feedstock, the lignin derivative having an aliphatic hydroxyl content of 2.35 mmol/g or less, the process comprising:
pulping the feedstock with a selected organic solvent (ETHANOL) supplemented with a selected acid catalyst (pH) for a selected period of time (TIME) at a selected temperature (TEMPERATURE) to produce a cellulosic solids fraction and an extractives liquid fraction;
separating the cellulosic solids fraction from the extractives liquid fraction; and
recovering the lignin derivative from an extractives liquid fraction, wherein the hardwood feedstock is an Acacia spp. and the parameters ETHANOL, pH, TIME, and TEMPERATURE are selected to satisfy the equation:
44.4758−17.3944*pH−0.342106*Temperature+0.373582*Ethanol−0.0133583*pH*Time+0.124198*pH*Temperature+0.000205204*Time*Time−0.00333743*Ethanol*Ethanol≦2.35.
2. A process according to claim 1 , wherein the Acacia spp. is an A. albida, A. cavenia, A. dealbata, A. decurrens, A. framesiana, A. meamsii, A. Melanoxylon, A. nilotica, A. penninervis, A. pycnatha, A. saligna , and combinations thereof.
3. A process according to claim 2 , wherein the recovered lignin derivative falls within the graphical representation of FIG. 2 .
4. A process for recovering a lignin derivative from a hardwood feedstock, the lignin derivative having an aliphatic hydroxyl content of 2.35 mmol/g or less, the process comprising:
pulping the feedstock with a selected organic solvent (ETHANOL) supplemented with a selected acid catalyst (pH) for a selected period of time (TIME) at a selected temperature (TEMPERATURE) to produce a cellulosic solids fraction and an extractives liquid fraction;
separating the cellulosic solids fraction from the extractives liquid fraction; and
recovering the lignin derivative from an extractives liquid fraction, wherein the hardwood feedstock is an Eucalyptus spp. and the parameters ETHANOL, pH, TIME, and TEMPERATURE are selected to satisfy the equation:
42.1508+4.21822*pH−0.5579848Temperature+0.352034*Ethanol−0.0197431*pH*Time+0.000758397*Time*Ethanol+0.00148659*Temperature*Temperature−0.000837671*Temperature*Ethanol−0.00251297*Ethanol*Ethanol≦2.35.
5. A process according to claim 4 , wherein the Eucalyptus spp. is an E. astrigens, e. clivicola, E. dielsii, E. forrestiana, E. gardneri, E. globulus, E. nitans, E. occidentalis, E. ornata, E. salubris, E. spathulata , and combinations thereof.
6. A process according to claim 5 , wherein the recovered lignin derivative falls within the graphical representation of FIG. 3 .