Cellulose oxidation by nitrogen dioxide in a perfluorinated tertiary amine solvent
US7645874B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 5, 2004 |
| Grant date | Jan 12, 2010 |
| Priority date | — |
| Expiry date | Sep 18, 2026 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61L31/042
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
This invention relates to a process for preparing bioabsorbable oxidized cellulose comprising combining cellulose material, with nitrogen dioxide and a nonaqueous solvent chosen from the class of perfluorinated tertiary amines. This invention also relates to a method of oxidizing cellulose material comprising introducing a solvent into the vessel, circulating the solvent through the cellulose material, adding nitrogen dioxide to said vessel containing the solvent and cellulose in the required amounts, circulating the solution for 7 to 24 hours while controlling the reaction temperature, and isolating the oxidized material. Preferably, isolation of the oxidized product is followed by first washing the oxidized cellulose material with cold water, then washing the oxidized cellulose material with an aqueous alcohol solution several times, then washing the material with 100% alcohol several times, and finally drying the oxidized material.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.