Lignin-based surfactants
View Patent ↗Methods for converting waste streams from the wood pulping industry to high-value surfactants are described. For example, isolated lignin and lignosulfonate or waste streams containing lignin and lignosulfonate can be directly converted to surfactants, or they can be first converted to methylol derivatives and treated with further reagents to produce surfactants.
1. A method of preparing a surfactant, the method comprising contacting a lignin-based material containing one or more methylol groups with an amino acid in a ratio of about 1:1 to about 1:1.3 based on moles of the one or more methylol groups in the lignin-based material to moles of the amino acid in presence of a solvent selected from triethylamine, or a mixture of triethylamine with n-butanol, to produce the surfactant.
2. The method of claim 1 , wherein contacting the lignin-based material with the amino acid comprises contacting the lignin-based material selected from lignin methylol, lignosulphonate methylol, and any combination thereof, with the amino acid in the solvent to produce the surfactant.
3. The method of claim 1 , wherein contacting the lignin-based material with the amino acid comprises contacting the lignin-based material with the amino acid selected from sodium salt of arginine, leucine, lysine, glycine, glutamic acid, aspartic acid, contrition sulfate, and any combination thereof, in the solvent to produce the surfactant.
4. The method of claim 1 , wherein contacting the lignin-based material with the amino acid occurs at a temperature of about 50° C. to about 70° C. for about 3 hours to about 4 hours with efficient mixing.
5. A method of preparing a Gemini surfactant, the method comprising contacting a lignin-based material containing one or more methylol groups with an amino acid in a ratio of about 1:1 to about 1:1.3 based on moles of the one or more methylol groups in the lignin-based material to moles of the amino acid in presence of a solvent selected from triethylamine or a mixture of triethylamine with n-butanol, to produce the Gemini surfactant, wherein number of reacted methylol groups with the amino acid is two or more per lignin molecule.
6. The method of claim 5 , wherein contacting the lignin-based material with the amino acid comprises contacting the lignin-based material selected from lignin methylol, lignosulphonate methylol, and any combination thereof, with the amino acid in the solvent.
7. The method of claim 5 , wherein contacting the lignin-based material with the amino acid comprises contacting the lignin-based material with the amino acid selected from sodium salt of arginine, leucine, lysine, glycine, glutamic acid, aspartic acid, contrition sulfate, and any combination thereof, in the solvent.
8. The method of claim 5 , wherein contacting the lignin-based material with the amino acid occurs at a temperature of about 50° C. to about 70° C. for about 3 hours to about 4 hours.