METHOD OF PRODUCING CARBOXYMETHYLATED LIGNOCARBOHYDRATE MATERIAL Russian patent published in 2009 - IPC C08B11/12 C08H5/04 

FIELD: chemistry.

SUBSTANCE: invention relates to chemical modification of lignocarbohydrate materials, which are used as sorbents. The method involves preliminary treatment of lignocarbohydrate material with formaldehyde in a propanol-2 medium in molar ratio formaldehyde: OH-group of the lignocarbohydrate material equal to (1-5):(1-90) in the presence of an acid catalyst and holding for 180 minutes at 40°C. Alkaline pre-treatment is carried out in molar ratio OH-group of the lignocarbohydrate material: NaOH equal to 1:1 at temperature 60°C for 120 minutes. Further, sodium monochloroacetate is added in molar ratio OH-group of the lignocarbohydrate material: ClCH₂COONa equal to 1:0.5, and is kept for 60 minutes at 60°C. The obtained product is washed with acidified mineral acid of ethanol and dried in air.

EFFECT: obtained product is characterised by high content of carboxylic groups, increased exchange capacity and is resistant to aqueous and non-aqueous media.

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