METHOD FOR SYNTHESIS OF CROSS-LINKED CARBOXYMETHYLATED LIGNIN-CARBON MATERIAL Russian patent published in 2010 - IPC C08B11/12 

FIELD: chemistry.

SUBSTANCE: invention relates to chemical modification of lignin-carbon materials (LCM) and is meant for synthesis of carboxymethyl esters of lignin-carbon materials. Lignin-carbon material is first treated with formaldehyde in a medium of propanol-2 in molar ratio formaldehyde:OH-groups of the LCM equal to (1-5):(1-30), in the presence of an alkaline catalyst at 40°C and the kept for 120 minutes. Alkaline pre-treatment is then carried out in molar ratio OH-groups of the LCM: NaOH equal to 1:1 at 60°C for 120 minutes. Sodium monochloro acetate is then added in molar ratio OH-groups of the LCM: ClCH₂COONa equal to 1:0.5, the mixture is held for 60 minutes at 60°C. The product is washed with ethanol acidified with inorganic acid and dried in air. Carboxymethyl esters of lignin-carbon materials can be used as sorbents.

EFFECT: product is characterised by high content of carboxyl groups and high exchange capacity, is resistant to aqueous and anhydrous media.

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