Process for manufacturing cellulose acetate
The invention provides a process for manufacturing at low cost cellulose acetate, which is useful as a biodegradable plastic, using corncob meal which has hitherto been thrown away as a raw material. More specifically, the invention provides a process for manufacturing cellulose acetate, which comprises the steps of: steaming corncob meal at a temperature of 150 to 250° C. and a pressure of 20 to 29 MPa; filtering the steamed corncob meal to obtain a solid product; and dehydrating and acetylating by adding acetic anhydride and sulfuric acid to the solid product. The steaming is preferably carried out by using a pressure vessel and the filtering is preferably carried out by using a filtering device.
1. A process for manufacturing cellulose acetate, comprising the steps of:
steaming a corncob meal in a sub-critical state at a temperature of 150 to 250° C. and a pressure of 20 to 29 MPa for 10 to 30 minutes to obtain a mixture of a solid product and a solution product, said solid product comprised of cellulose, said solution product comprised of soluble hemicelluloses and polyphenol converted from lignin separated from lignocelluloses in the corncob, said sub-critical state being such that the solid product and the solution product are obtained from the corncob meal solely due to the temperature and pressure conditions of the state;
filtering the mixture to separate the solid product;
dehydrating the solid product; and
acetylating the dehydrated solid product in the presence of acetic anhydride and sulfuric acid to obtain cellulose acetate from the solid product.
2. The process according to claim 1 , wherein the steaming is carried out in a pressure vessel and the filtering is carried out by a filtering device.
3. The process according to claim 1 , wherein the steaming is carried out at a temperature of 180 to 200° C. and a pressure of 25 to 28 MPa.
4. The process according to claim 1 , wherein, in the steaming step, 10 to 1000 parts by weight of water is added relative to 100 parts by weight of corncob meal.
5. The process according to claim 1 , wherein, in the steaming step, a sulfurous acid compound is added to the corncob meal.
6. The process according to claim 5 , wherein the sulfurous acid compound is added in the amount of 1 to 10 parts by weight for 100 parts by weight of the corncob meal.
7. The process according to claim 5 , wherein, in the dehydrating and acetylating step, the sulfuric acid is added in the amount of 1 to 10 parts by weight, and the acetic anhydride is added in the amount of 1 to 20 parts by weight, relative to 100 parts by weight of dry cellulose.
8. The process according to claim 1 , wherein the dehydrating and acetylating is carried out under conditions of a pressure of 5 to 15 MPa, a temperature of 60 to 100° C., a stirring speed of 30 to 100 rpm and a treatment time of 15 to 30 hours.
9. A process for manufacturing cellulose acetate, comprising the steps of:
steaming a corncob meal at a temperature of 150 to 250° C. and a pressure of 20 to 29 MPa;
filtering the mixture to separate the solid product;
dehydrating the solid product; and
acetylating the dehydrated solid product in the presence of acetic anhydride and sulfuric acid at a temperature of 60 to 100° C. and a pressure of 5 to 15 MPa for 15 to 30 hours as a single process to obtain cellulose acetate from the solid product.
10. A process for manufacturing xyloligosaccharides, comprising:
steaming a corncob meal under conditions of a temperature of 150 to 250° C. and a pressure of 20 to 29 MPa;
filtering the steamed corncob meal to obtain a filtrate from which solid has been removed;
performing an enzyme treatment by reacting xylanase with soluble xylan in the filtrate to hydrolyze the soluble xylan;
removing any suspended matter from a reaction product obtained during the enzyme treatment; and
drying the reaction product.
11. The process according to claim 10 , wherein the steaming is carried out in a pressure vessel and the filtering is carried out by a filtering device.
12. The process according to claim 10 , wherein the steaming is carried out under conditions of a temperature of 180 to 200° C. and a pressure of 25 to 28 MPa.
13. The process according to claim 10 , wherein, in the steaming, 10 to 1000 parts by weight of water is added relative to 100 parts by weight of corncob meal.
14. The process according to claim 10 , wherein the steaming is carried out for 10 to 30 minutes.
15. The process according to claim 10 , wherein, in the steaming, a sulfurous acid compound is added to the corncob meal.
16. The process according to claim 15 , wherein the sulfurous acid compound is added in the amount of 1 to 10 parts by weight for 100 parts by weight of the corncob meal.
17. The process according to claim 10 , wherein the xylanase is added in the amount of 0.1 to 5 parts by weight relative to 100 parts by weight of the filtrate.
18. The process according to claim 10 , wherein the enzyme treatment is carried out under conditions of a pH of 3 to 8, a temperature of 30 to 50° C., a stirring speed of 60 to 200 rpm and a treatment time of 15 to 30 hours.
19. The process according to claim 10 , wherein the steaming is performed by two or more sequentially connected extruders having pressure-sealed cylinders; the levels of temperature and pressure set rise gradually, beginning with the first connected extruder until the last connected extruder; and the steaming conditions for the last connected extruder satisfy the conditions of a temperature of 150 to 250° C. and a pressure of 20 to 29 MPa.