METHOD FOR OXYGEN-NATRON DEGRADATION OF CARBOHYDRATE PART OF CELLULOSE FOR PAPER Russian patent published in 2025 - IPC D21C9/00 D21C3/00 

FIELD: chemistry; cellulose production.

SUBSTANCE: invention relates to a method for oxygen-natron degradation of the carbohydrate portion of cellulose for paper. In the disclosed method, the cellulose-containing raw material used is commercial bleached softwood cellulose for production of paper from softwood, which is subjected to two-stage treatment. Treatment includes acid hydrolysis with an aqueous solution of SO₂ or acid chelating treatment with ethylenediaminetetraacetic acid in the presence of sulphuric acid under the following conditions: pH from 2.0 to 4.0, temperature from 35 to 80 °C, duration of 60 minutes at dry substance concentration of 4% and oxygen-natron degradation with sodium hydroxide solution in the presence of hydrogen peroxide and oxygen activators or without them under the following conditions: pH 12.0, temperature from 20 to 115 °C, duration is 90 minutes. Alkaline treatment can be carried out both under pressure and without, and the sequence of treatment steps can be interchanged.

EFFECT: invention increases the fraction of alpha-cellulose in cellulose and enables to obtain high-quality cellulose.

1 cl, 4 ex