Method for partially oxidizing sodium alginate

[0024] Example one

[0025] Weigh 1 g of sodium alginate and add it to 100 ml of deionized water, and magnetically stir until the sodium alginate is completely dissolved to obtain a 1% (w/v) sodium alginate solution. Weigh 1.5878g of potassium permanganate in 100ml of distilled water, stir and boil. After the potassium permanganate is fully dissolved, let it stand in the dark for 6 days, and finally take the upper clear solution for calibration. The concentration of the potassium permanganate solution is 0.1227mol /L, keep in brown bottle for later use. Add 0.5 ml (1:5) concentration of sulfuric acid aqueous solution dropwise to the sodium alginate solution, adjust the pH value to 4, and fully stir the solution. Next, accurately measure 1.5ml of the above potassium permanganate solution and add it to the sodium alginate solution, stir the reaction at room temperature and avoid light, and stop the oxidation reaction when the solution becomes colorless. Add 0.30g of sodium chloride to the reacted solution, add 250ml of ethanol to precipitate the precipitate after fully dissolving, and vacuum filtration to obtain the crude product. The crude product is fully dissolved in 50ml of water and then put into a dialysis bag (cut offMw= After dialysis in 10000), the dialysate is placed in a low-temperature refrigerator for pre-freezing for 12 hours after the dialysate is dialyzed, and then freeze-dried to obtain a partially oxidized sodium alginate product. The degree of oxidation of the product was determined to be 11.2%.

[0026] Embodiment two

[0027] Weigh 1 g of sodium alginate and add it to 100 ml of deionized water, and magnetically stir until the sodium alginate is completely dissolved to obtain a 1% (w/v) sodium alginate solution. Weigh 2.3756g of potassium permanganate in 100ml of distilled water, stir and boil. After the potassium permanganate is fully dissolved, let it stand in the dark for 8 days, and finally take the upper clear solution for calibration. The concentration of the potassium permanganate solution is 0.1671mol. /L, keep in brown bottle for later use. Add 0.5 ml (1:5) concentration of sulfuric acid aqueous solution dropwise to the sodium alginate solution, adjust the pH value to 4, and fully stir the solution. Then accurately measure 1.0 ml of the above potassium permanganate solution and add it to the sodium alginate solution, stir and react in the dark at room temperature, and stop the oxidation reaction when the solution becomes colorless. Add 0.30g of sodium chloride to the reacted solution, add 250ml of ethanol to precipitate the precipitate after fully dissolving, and vacuum filtration to obtain the crude product. The crude product is fully dissolved in 50ml of water and then put into a dialysis bag (cut offMw= After dialysis in 10000), the dialysate is placed in a low-temperature refrigerator for pre-freezing for 12 hours after the dialysate is dialyzed, and then freeze-dried to obtain a partially oxidized sodium alginate product. The degree of oxidation of the product was determined to be 6.66%.

[0028] Embodiment three

[0029] Weigh 1 g of sodium alginate and add it to 100 ml of deionized water, and magnetically stir until the sodium alginate is completely dissolved to obtain a 1% (w/v) sodium alginate solution. Weigh 1.2683g of potassium permanganate in 100ml of distilled water, stir and boil. After the potassium permanganate is fully dissolved, let it stand in the dark for 4 days, and finally take the upper clear solution for calibration. The concentration of the potassium permanganate solution is 0.0848mol /L, keep in brown bottle for later use. Add 0.3 ml (1:5) concentration of sulfuric acid aqueous solution dropwise to the sodium alginate solution, adjust the pH value to 3.5, and fully stir the solution. Then accurately measure 0.5ml of the above potassium permanganate solution and add it to the sodium alginate solution, stir and react in the dark at room temperature, and stop the oxidation reaction when the solution becomes colorless. 0.30g of sodium chloride was added to the obtained filtrate, 250ml of ethanol was added to precipitate the precipitate after being fully dissolved, and the crude product was obtained by suction filtration under reduced pressure. The crude product was fully dissolved in 50ml of water and then filled into a dialysis bag (cut offMw=10000 After the dialysate is dialyzed, the dialysate is placed in a low-temperature refrigerator for pre-freezing for 12 hours and freeze-dried to obtain a partially oxidized sodium alginate product. The degree of oxidation of the product was determined to be 9.52%.