One-pot homogeneous preparation of chitin and chitosan derivatives with different degrees of deacetylation from chitin
A technology of chitosan derivatives and degree of deacetylation, applied in the field of polymers, can solve problems such as low degree of deacetylation, and achieve the effects of controllable reaction and easy operation
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Embodiment 1
[0025] Add chitin raw material (degree of deacetylation is about 3%) into 40wt% KOH solution and heat at 40°C for 2 minutes to obtain a mixed solution of chitin and alkali with a degree of deacetylation of 5%, cool down to below 30°C, and add a certain amount of The water and urea make the mass fraction of KOH in the solution be 10-25wt%, and the mass fraction of urea be 0-10wt%, stir and dissolve rapidly at a temperature above the freezing point, and obtain a chitin solution with a concentration of 1.0wt% after centrifugal defoaming . According to the material ratio of sodium chloroacetate and chitin monomer unit is 0.5:1, add to the chitin solution obtained above, stir at 0°C for 20h, adjust the pH value of the solution to about 7, purify by dialysis and freeze-dry Carboxymethyl chitin was obtained with a degree of substitution of 0.18.
Embodiment 2
[0027] Add chitin raw material (degree of deacetylation is about 3%) into 40wt% KOH solution and heat at 80°C for 1 hour to obtain a mixed solution of chitin and alkali with a degree of deacetylation of about 10%, cool down to below 30°C, add certain A large amount of water and urea make the mass fraction of KOH in the solution be 10-25wt%, and the mass fraction of urea be 0-10wt%, stir and dissolve quickly at a temperature above freezing point, and obtain chitin with a concentration of 0.5wt% after centrifugal defoaming solution. According to the material ratio of sodium chloroacetate and chitin monomer unit is 0.1:1, add to the chitin solution obtained above, stir at -15°C for 24 hours, adjust the pH value of the solution to about 7, dialysis purification and freezing Dried to obtain carboxymethyl chitin with a degree of substitution of 0.08.
Embodiment 3
[0029] Chitin raw material (deacetylation degree is about 3%) is added to 60wt% KOH solution and heated at 80°C for 30min to obtain a mixed solution of chitosan and alkali with a deacetylation degree of about 60%, cooled to below 30°C, and added A certain amount of water and urea make the mass fraction of KOH in the solution 10-25wt%, and the mass fraction of urea 0-10wt%, stir and dissolve quickly at a temperature above the freezing point, and obtain chitin with a concentration of 1wt% after centrifugal defoaming solution. According to the substance ratio of sodium chloroacetate and chitin monomer unit is 40:1, add to the chitin solution obtained above, stir at 0°C for 24 hours, adjust the pH value of the solution to about 7, purify by dialysis and freeze-dry Carboxymethyl chitosan was obtained with a degree of substitution of 2.12.
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