METHOD FOR PRODUCING FIBROUS CELLULOSE FROM HEMP Russian patent published in 2024 - IPC D21C5/00 D21C9/16 

FIELD: chemical industry.

SUBSTANCE: production of fibrous cellulose for the synthesis of cellulose derivatives. The method for producing fibrous cellulose from hemp includes acid, alkaline, alkaline-oxidative, acid treatment, washing, squeezing, loosening, drying, while the cellulose-containing fibrous mass is treated in an aqueous solution of nitric acid with a concentration of 0.5-5 g/l at a temperature of 75-90°C for 30-90 minutes. Then in an aqueous solution containing sodium hydroxide with a concentration of 10-25 g/l and a chemical cottonization intensifier based on organic nitrogen compounds and inorganic salt with a concentration of 1-5 wt.%, at a temperature of 85-95°C for 60-120 minutes, carry out alkaline-oxidative treatment in an aqueous solution containing sodium hydroxide with a concentration of 5-10 g/l, hydrogen peroxide with a concentration of 2.8-4.0 g/l in terms of active oxygen, a hydrogen peroxide stabilizer based on organic chelating compound with a concentration of 0.1-1.5 g/l, at a temperature of 80-85°C for 30-90 minutes, treated in an aqueous solution of nitric acid with a concentration of 0.5-3.0 g/l at a temperature of 50-65°C for 20-40 minutes, then washed with water at a temperature of 18-25°C for 20-30 minutes, squeeze out, loosen and dry.

EFFECT: high quality of cellulose in terms of: mass fraction of α-cellulose, mass fraction of lignin, mass fraction of residue insoluble in sulfuric acid, wettability, mass fraction of fibrous dust, mass fraction of ash, dynamic viscosity and high product yield, increasing the efficiency, production and environmental safety of the process, expanding the possibility of recycling short hemp fiber as a cellulose-containing annually renewable raw material, which is important for solving the problems of replacing wood and imported cotton raw materials.

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