Patent EA-000169-B1 (EA)
Title: Process for activating polysacchharides, polysacchharides produced by this process, and use thereof
Inventor: KARSTENS TIES
IPC: C08B1/00
Filed: 1996-03-22
Abstract: 1. A process for activating polysaccharides, wherein the polysaccharide starting material is brought into contact with liquid ammonia at an initial pressure which is higher than atmospheric pressure and at a temperature of at least approximately 25 degree C, the amount of liquid ammonia being sufficient at least for wetting the surface of the polysaccharide starting material which is then expanded wherein the volume available for the polysaccharide/liquid ammonia system is enlarged in the manner of an explosion by lowering the pressure by at least 5 bar. 2. A process according to Claim 1 wherein said volume is enlarged in the manner of an explosion during less than 1 sec. 3. A process according to Claim 1 or 2 wherein starting material is brought into contact with liquid ammonia in a device with a pressure and said polysaccharide/liquid ammonia system is enlarged by transferring into an explosion chamber volume of which is larger than that of said chamber. 4. A process according to any of preceding Claims, wherein said initial pressure is set from about 5 to 46 bar, preferably from 25 to 30 bar. 5. A process according to any of preceding Claims, wherein the temperature in said device prior to explosion-like lowering of said initial pressure is set between 25 to 85 degree C, preferably from 55 to 65 degree C. 6. A process according to any of preceding Claims, wherein said initial pressure is lowered explosion-like by at least 1o bar, preferably by 30 bar. 7. A process according to any of preceding Claims, wherein for 1 part by weight of polysaccharide 1, preferably 5-10 parts by weight of liquid ammonia are used. 8. A process according to any of preceding Claims, wherein evaporated ammonia due to explosion-like volume enlargement is condensed to a liquid state and further recycled. 9. A process according to any of 3-8 preceding Claims, wherein prior to bringing polysaccharide starting material into contact with liquid ammonia, vacuum is maintained in said explosion chamber. 10. A process according to any of preceding Claims, wherein polysaccharide is used having polyhexose skeleton. 11. A process according to Claim 10, wherein cellulose is used as polysaccharide. 12. A process according to Claim 11, wherein compact chemicellulose is used as cellulose having density of about from 0.6 to 0.8 g/cm<3>. 13. A process according to Claim 10, wherein galactomannan is used as polysaccharide. 14. A process according to Claim 13, wherein guar gum is used as galactomannan. 15. A process according to Claim 10, wherein starch is used as polysaccharide. 16. A process according to Claim 10, wherein chitin is used as polysaccharide. 17. A process according to any of preceding Claims, wherein said polysaccharide starting material contains water in an amount less than 12% by weight, preferably less than 9% by weight. 18. A process according to any of preceding Claims, wherein said polysaccharide starting material contains less than 18% of admixtures. 19. A process according to any of preceding Claims, wherein said polysaccharide starting material contains no proteins. 20. A process according to any of preceding Claims, wherein for removal of residual ammonia the final product is vacuumed and/or heated. 21. Polysaccharide in the form of crystal cellulose, wherein said polysaccharide has Roentgen diffraction spectre with peaks having angles of deviation 2θ and following intensities: peak 11.25 +- 1 with relative intensity of about 15-25; peak 17 +- 1 with relative intensity of about 25-40; peak 20.5 +- 1 with relative intensity 100 (relative value). 22. Cellulose according to Claim 21, wherein the value of limited rate of polymerization is about from 50 to 200, preferably, from about 100 to 160. 23. Cellulose according to Claim 21 or 22 wherein said cellulose is in the form of flakes with density less than 0.2 g/cm<3> preferably less than 0.1 g/cm<3>. 24. Cellulose according to Claim 23 wherein said flakes comprise less than 0.5% by weight of ammonia. 25. Use of cellulose according to any of preceding Claims 21-24 to obtain cellulose derivatives in particular by acylation, alkylation, silylation, xanthogenation and carbamoylation. 26. Use of cellulose according to any of preceding Claims 21-24 to obtain a solution for wet spinning.