Crystalline sulphated cellulose II and its production from sulphuric acid hydrolysis of cellulose
US8309708B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 5, 2010 |
| Grant date | Nov 13, 2012 |
| Priority date | — |
| Expiry date | Sep 9, 2030 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08B15/08
- WIPO fieldPharmaceuticals
- WIPO sectorChemistry
Abstract
A method for producing crystalline sulphated cellulose II materials with relatively low degree of polymerization from spent liquors of sulphuric acid (H2SO4) hydrolysis of cellulose has been discovered. The method involves: 1) separating the spent liquors from the hydrolysed, acid-insoluble, cellulose I materials by dilution from, for example, a 64% H2SO4 hydrolysis medium to a residual sulphuric acid concentration of 10-50% with 0-40% H2SO4, followed by settling (or centrifuging) and decanting; 2) adding the diluted spent liquors to water or heating the diluted spent liquors at 30-80° C. for ≦48 h; and 3) recovering the recrystallized sulphated cellulose II materials with relatively low degree of polymerization either by filtration and washing or by washing and freeze drying. The method can be used to concurrently produce both crystalline, sulphated cellulose I and the crystalline, sulphated cellulose II materials.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.