Study on Carboxymethyl Ation of Chitosan and the Process
|School||Hebei University of Science and Technology|
|Keywords||Chitosan Carboxymethyl chitosan Solvation effect Degree of substitution Viscosity|
This thesis for the dispersed phase to organic solvents , sodium hydroxide as an alkalizing agent , chloroacetic acid as a modifier , isoelectric point method refined preparation of carboxymethyl chitosan . Expounded the the carboxymethyl chitosan preparation method and process mechanism . More systematic dosage of sodium hydroxide , chloroacetic amount of etherification temperature , etherification , and organic solvents select five factors to consider , product substitution of carboxymethyl chitosan yield , water-soluble and dissolved rate , quantitative research and analysis to find the factors the law . Using isopropanol as the organic solvent , obtained by orthogonal experiment carboxymethyl chitosan optimum conditions : chitosan 5g, sodium hydroxide 20g , the chloroacetic 25g , swelling temperature 30 ℃ , swelling 1h, alkali transition temperature of 30 ° C , the alkalization time 2h ??, etherification temperature of 50 ° C , etherification time 4h, chloroacetic slow in batches to join with isoelectric point refined products , carboxymethyl chitosan prepared under this condition the degree of substitution of 1.382 , the closing rate of 85.1% , better water-solubility , viscosity, yield , dissolution rate and infrared spectroscopy performance indicators for the analysis and characterization and on the degree of substitution of carboxymethyl chitosan products . Traditional craft of carboxymethyl chitosan is generally carried out in heterogeneous conditions , larger than the amount of sodium hydroxide and chloroacetic use , and the low utilization rate of raw materials , had a great impact on the environment , increase the carboxylation chitosan production costs . Solvation effect of chitosan carboxymethylation heterogeneous system had a significant effect , it can improve product performance , reduce the amount of alkali and acid , and to improve the utilization of raw materials , cost savings , chitosan carboxymethyl base the process of gradually attention , is a very application preparation techniques prospects .