Preparations Of New Functional Starch Derivatives And Their Adsorption For Creatinine

Professor Yu Jiugao ЗРЯС-4 Certificate: PassedIn this paper starch 3,5-dinitrobenzoate (DSt) and (amino or ammonium)starch 3,5-dinitrobenzoate were first prepared based on the complexation reaciton theory of 3,5-dinitrobenzoic acid and creatinine. These derivatives were employed as a new adsorbent used for removing creatinine. The procedures and results are shown as the following. The products are characterized by FTIR, elemental analysis, 13CNMR, X-ray diffraction, TG and SEM. Effects of molar ratio of the raw material, reaction temperature, reaction time, and the amount of catalyst on the degree of substitution (DS) of DSt and amino(or ammonium)-DSt were studied. It is shown from the experiment results that in this esterifaction reaction the activity of the hydoroxy in C6 and C2 is higher than in C3. To obtain the product with higher DS, the optimal synthesis condition is that the molar ratio of DNBZ-Cl:AGU:pyridine should be 4:1:53, the reaction temperature should be at 90℃ and the reaction time should be 2h. The preparation of 3-chloro-2-hydroxypropyl starch ether(ESt) with higher DS was the key for preparing amino-DSt. The ESt with higher DS was obtained when molar ratio of AGU: epoxy chloropropane: perchloric acid: H2O was 1:6.26:0.034:0.1008, reaction temperature was 100℃ and reaction time was 3.5h. The adsorption properties of DSt samples for creatinine were examined in the dialysate. The results showed that DSt has good stability, adsorption selectivity and high adsorption capacity(AC). The adsorption equilibrium is reached after 4h. The adsorption capacity of DSt increases with its DS(0~2.09) and creatinine concentration. The equilibrium AC and the saturated AC of DSt(DS=2.09) reached 3.02mg·g-1 and 10mg·g-1 respectively. The AC first increased and then decreases as the pH value increases from 4 to 11, and is highest at pH 8.With the similar value of DS, the equilibrium AC and the saturated AC of amino(or ammonium)-DSt were higher than that of DSt. The pH value has slighteffect on the equilibrium AC of amino(or ammonium)-DSt. The adsorption of diethylamino-DSt(DS1=0.24, DS2=1.84) has the highest speed to equilibrium, highest equilibrium AC ( 4.02mg·g-1 )and saturated AC(12.50mg·g-1 ).The study on the alkali reaction system that consists of creatinine and 3,5-dinitrobenzoic acid (DNBA) By HNMR, 13CNMR and UV-VIS shows that the methylene group of creatinine molecule tends to lost proton easily. The rose-colored reaction product (1:1бcomplex) was formed through the methylene group of creatinine attaches to arometic ring of DNBA.The adsorption of cretinine on the DSt in dialysate could be attributed to the formation of бcomplex between creatinine and aromatic ring of DSt molecule. The amine could produce alkalescence around molecule in the dialysate. Thus, increase the AC of amino-DSt. The adsorption product of C-DSt contained both electrostatic complex and бcomplex...