Method for methylolation of lignin materials
US4764597A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 15, 1987 |
| Grant date | Aug 16, 1988 |
| Priority date | — |
| Expiry date | Jun 15, 2007 |
Classification
- Technology area (CPC D)Textiles; Paper
- CPC primaryD21C11/04
- WIPO fieldTextile and paper machines
- WIPO sectorMechanical engineering
Abstract
An improved method of producing methylolated lignins from the black liquor residue of a kraft wood-pulping process, which methylolated lignins may be further employed in other chemical reactions, such as in the production of sulfomethylated lignin salts suited for use as dyestuff dispersants, comprising the steps of oxidizing the black liquor residue of a kraft wood-pulping process containing lignin, organic, and inorganic salts, treating the black liquor residue with an aldehyde to methylolate the lignin therein, lowering the pH of the black liquor residue to precipitate the lignin therefrom, and isolating and recovering the methylolated lignin for subsequent chemical reactions. The black liquor residue of the kraft pulping process is oxidized, before methylolation of the lignin therein, to reduce the presence of sodium sufide in the black liquor residue to about 1 percent or less.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.