Study On Synthesis And Properties Of The Derivatives Of Cellulose-Based Picric Acid

Chronic renal failure(CRF)is severe disease which is characterized by clinical symptom of poisoning,depositing large numbers of toxins in organism is the main cause of CRF,therefore Removal of the excess toxins is the key problem for the treatment of CRF.Urea and creatinine are two of the major toxins to the patient who suffered from chronic renal failure.In this study,according to the properties of urea and creatinine,two new oral adsorbent named ether of microcrystalline cellulose-based picric acid(MCC-PA) and ester of dialdehyde cellulose-based picric acid(DAC-PA)were prepared and their adsorption for creatinine and urea were studied.The new ether of microcrystalline cellulose-based picric acid(MCC-PA)was prepared from microcrystalline cellulose by the reaction of epoxidation and etherification.The structure of MCC-PA was analyzed by FTIR,element analyzer,XRD,etc.Influences of reaction conditions such as the ratio of epoxy cellulose and picric acid(PA),volume of NaOH(36%,by weight),reaction time and reaction temperature were investigated with nitrogen content as optimization index.The results showed that the synthetical conditions was that the ratio of epoxy cellulose and Picric acid was 5 to 1 by weight,the volume of NaoH(36%,by weight) was 30 mL,reaction temperature was 45℃and reaction time was 3 hours with the nitrogen content of 2.22%by single-factor experiment.The FTIR showed that MCC-PA have been synthesized,and the XRD showed that the degree of crystallinity of MCC-PA is 75.7%.The adsorption property of MCC-PA for creatinine were studied under simulated biological conditions and The kinetic curve was drawn.The results showed that adsorption equilibrium reached after 18 hours and the maximal adsorption capacity for creatinine was 2.49mg/g.The multi-effect oral adsorbent DAC-PA was prepared by esterification of DAC and picric acid with oxalyl chloride as substance for crosslinking reaction and pyridine as solvent and catalyst.The product was characterized by FTIR,XRD,SEM.investigated The effects of molar ratio of the materials,reaction temperature in the first step(T1),reaction time in the first step(H1),amount of dialdehyde cellulose,reaction temperature in the second step(T2) and reaction time in the second step(H2)were investigated with adsorbtion capacity of DAC-PA for creatinie as optimization index.The results showed that a high adsorption capacity for creatinine of 3.5mg/g was obtained when the molar ratio of oxalyl chloride to picric acid was 1.1 to 1,T1 was 3 hours,H1 was 40℃,the amount of dialdehyde cellulose was 1g,T2 was 75℃,H2 was 4h.The FTIR showed that MCC-PA have been synthesized,XRD and SEM showed that both crystal structure and surface structure of DAC-PA had been changed.The adsorption property of MCC-PA for creatinine and urea were studied under simulated biological conditions and the kinetic curve was drawn.The results showed that adsorption equilibrium for creatinine reached after 10 hours and the maximal adsorption capacity for creatinine was 3.5mg/g while the adsorption equilibrium for urea reached after 10 hours and the maximal adsorption capacity for urea was 23.7mg/g.Equilibrium data of creatinine fitted well with Freundich equation within temperature range from 20℃to 50℃and investigative concentration range.The adsorption of creatinine on MCC-PA was a chemically endothermic process.Dialdehyde cellulose 3,5-dinitrobenzoate which contained ester bond and had good adsorption for urea and creatinine was selected for study of Stability,Because 3,5-Dinitrobenzoic acid which is the hydrolysate of DCNB is an acidic substance,and dissociative 3,5-Dinitrobenzoic acid might stimulates gastrointestinal mucous membrane,adsorption capacity of DCNB for urea and creatinine might change when it is exposured in the air for a period of time,moreover hydrolysis product of DCNB is single and convenient to detect.The stability properties of DCNB were studied under simulated body conditions in the paper.The influence of pH,hydrolysis time and time exposured in the air to stability of DCNB was studied.The results showed that between 4 to 6 hours,the hydrolysis rate of DCNB is 0.06% 0.11%,0.01%～0.03%and 3.01%～3.50%in the buffer solution of pH=1,pH=2 and pH=8 respectively.When the DCNB was exposured in the air for six month,The Saturated adsorption capacity of DCNB for urea and creatinine didn't change obviously compared with new-made DCNB.In conclusion,the DCNB had a good stability property.