Synthesis And Optimization Of The Reaction Conditions Of Starch Sulfates

To study on the synthesis and optimization of the reaction conditions of starch sulfate, in this paper, we synthesized the starch sulfate with potato starch by three different methods respectively and investigated the factors that could affect the degree of substitution (DS) in the process of reactions systematically. Then, the optimal conditions of these three methods were obtained separately. The main results are summarized as follows:1. Starch sulfate was synthesized by chemical modification of potato starch with sulfuric acid in ethanol. The reaction conditions including the ratio of starch mass to sulfuric acid volume, the concentration of ethanol, the volume ratio of ethanol to sulfuric acid, the reaction temperature and reaction time of sulfation were studied. By the relationship between these conditions and DS, the optimal conditions of this method were obtained. FTIR spectrum showed the characteristic absorptions of starch sulfate. And the DS values of starch sulfate were determined by barium sulfate-glutin nephelometery method.2. Starch sulfate was obtained by the reaction between potato starch and chlorosulfonic acid in pyridine. The factors that could affect the DS in the process of preparing sulfating agent were investigated in detail, which included the volume ratio of pyridine to chlorosulfonic acid and the reaction temperature and time in this process. And the ratio of chlorosulfonic acid volume to starch mass, the reaction temperature and time of synthesizing starch sulfate were studied in the process of sulfation of potato starch to obtain the relationship between these conditions and the value of DS. Because of the results of these studies, the optimal conditions of this method were obtained. The characteristic absorptions of starch sulfate were showed by FTIR spectrum. And all DS of the starch sulfate samples were determined by barium sulfate-glutin nephelometery method.3. To synthesize starch sulfate in aqueous solution, the reactions between sodium bisulfite, sodium nitrite and potato starch were carried. The reaction conditions in the preparing sulfating agent process and the sulfation process were studied in systematically, which included the molar ratio of sodium bisulfite to sodium nitrite, the reaction temperature and time of preparing sulfating agent, and the pH of sulfation, the dosage of sulfating agent and potato starch, the ratio of liquid volume to starch mass, and the reaction temperature and time of synthesizing starch sulfate. Finally, the optimal conditions were obtained by the results of these studies. The structure of starch sulfate was verified by FTIR spectrum. And the values of DS were determined by barium sulfate-glutin nephelometery method and elemental analysis method respectively.