辛烯基琥珀酸菊粉酯的制备及其结构分析

Preparation and Structural Characterization of Octenyl Succinic Anhydride Modified Inulin

以取代度（Ds）为指标，利用单因素试验研究了菊粉浓度、反应温度、pH值、OSA添加量等因素对制备辛烯基琥珀酸菊粉酯的影响，通过正交试验确定了适宜制备工艺条件为：菊粉浓度为25％，OSA／AFU摩尔比为0．35，pH8．5～9．0，反应温度30℃，在该工艺条件下所得产品取代度为0．0342。对制备产品的结构采用扫描电镜（SEM）、红外光谱仪（FT-IR）、核磁共振光谱做（^13CNMR和^1HNMR）等进行表征分析，结果表明：菊粉经过辛烯基琥珀酸酐（OSA）修饰后，其颗粒表面受到侵蚀，出现凹槽、破损孔纹。红外光谱图显示菊粉酯化后在1733．72cm^-1、1569．80cm^-1处分别出现酯键中羰基（C=O）振动和OSA上的烯基（C=C）伸缩振动的特征吸收峰。^13CNMR谱图中在化学位移175．6ppm和176．5ppm处出现羰基碳和羧基碳的特征峰；1HNMR谱图中在化学位移1-2ppm、0．8ppm附近出现OSA分子亚甲基和甲基质子峰。这均证实了OSA基团以酯键形式连接到菊粉分子上。

The preparation of octenyl succinic anhydrid （OSA） modified inulin in aqueous medium was studied. The effects of the inulin concentration, reaction temperature, pH value, the additive amount of OSA were investigated by single factor experiments with the degree of substitution （DS） as measurement index. The synthetic conditions of OSA modified inulin which were optimized by orthogonal analysis were as follows： OSA/AFU molar ratio of 0.35, temperature 30℃, pH 8.5～9.0, 25% （m/m） concentration of inulin. The structures of the product were determined by means of scanning electron microscopy（SEM）,fourier transform infrared spectroscopy（FT-IR）, carbon-13 and proton nuclear magnetic resonance spectroscopy （13C NMR and 1H NMR）. The results showed that the surface structure of OSA modified inulin particles were damaged and lost their original smooth surface structure. Infrared datas showed that carbonyl absorption peak of ester bond appeared at 1733.72 cm^-1 and alkenyl absorption peak of octenyl succinic anhydride appeared at 1569.80 cm^-1. Characteristic absorption peaks of the carbonyl carbon and carboxyl carbon were appeared at 175.6 ppm and 176.5 ppm in the 13C NMR diagram. The absorption peaks of methylene protons and methyl protons in the chain of OSA molecule were discovered about 1.2ppm, 0.8ppm chemical shift in the 1H NMR diagram. These results demonstrated that the OSA group had been linked with inulin molecules by the ester bond.