双醛葡甘聚糖的合成及表征

Research on the Synthesis of Dialdehyde Glucomannan and Its Characterization

[目的]优化双醛葡甘聚糖(DAKGM)的合成条件。[方法]室温下以高碘酸钠(NaIO4)作氧化剂氧化葡甘聚糖(KGM),制备DAKGM,探讨反应物料摩尔比、反应时间、体系酸碱度等因素对产物DAKGM中醛基含量的影响,通过红外光谱(FTIR)、核磁共振氢谱(1H NMR)、热重分析(TG)对DAKGM进行结构与性能表征。[结果]酸性体系有利于氧化反应进行,随着酸度的增加,DAKGM醛基含量略有增加;氧化剂用量过多,KGM容易产生降解并导致产物醛基含量降低,热稳定性变差;氧化时间在24 h内,产物中醛基含量随氧化时间的延长近似呈线性增长。[结论]反应温度为室温,反应时间为24 h,NaIO4∶KGM=1.2∶1.0(摩尔比),pH值为7.0时,所得DAKGM的醛基含量为135.32 mmol/mol。

[Objective] The condition of dialdehyde glucomannan（DAKGM） synthesis was optimized through the experiment.[Method] The DAKGM was prepared by means of the method o through the oxidation of glucomannan（KGM） with sodium periodate as oxidants at room temperature.The effect of the molar ratio of reactant and material,the reaction time,the pH value in reaction system and others on the content of aldehyde in the product——DAKGM was analyzed and the structural and functional characterization of DAKGM was explored with the technique of infrared spectroscopy（FTIR）,nuclear magnetic resonance spectroscopy（1H NMR） and thermogravimetric analysis（TG）.[Result] The acid reaction system was conducive to oxidation reaction and with the increment of acidity in the reaction system,the content of aldehyde in DAKGM was slightly increased.The excess addition of the oxidant would resulted in the easy degradation of KGM so that the content of aldehyde was reduced and the thermal stability was weak.Within 24 hours＇ oxidation time,the content of aldehyde in product was linearly increased with the its oxidation time-prolonging.[Conclusion] The content of aldehyde in DAKGM was 135.32 mmol/mol while the reaction temperature was room temperature;the reaction time was 24 hours;the ratio of NaIO4∶KGM was 1.2∶1.0（molar ratio） and the pH value was 7.0.