半乳聚糖的化学合成及表征

Chemical synthesis,structural characterization of galactan

本文研究了氯化亚砜和水作为催化剂催化半乳糖聚合的方法。探讨了水用量、温度和时间对半乳聚糖收率的影响,并通过核磁碳谱和体积排除色谱表征了合成的半乳聚糖糖单元的连接方式和重均分子量。在水与半乳糖的质量比为0.10、氯化亚砜与半乳糖的摩尔比为0.24、反应温度为70℃、时间为50 min的条件下,半乳聚糖的收率最高,达到69%,重均分子量为8700。根据对半乳聚糖的核磁碳谱的分析,半乳聚糖的端基碳原子α构象占58%,β构象占42%。半乳聚糖的糖单元67%为1→6连接,18%为1→4连接,9.4%为1→3连接,5.6%为1→2连接。

In this paper, galactan was successfully prepared with thionyl chloride and water as catalysts. The effects of the dosage of the water,reaction temperature and reaction time on the yield of galactan were investigated. The weight average molecular and struc- ture of galactan were determined by means of SEC and 13 C NMR spectroscopy. Under conditions of the mass ratio of water to galactose was 0. 10,that of thionyl chloride to galactose was 0. 24,70 ℃ and 50 min,the highest yield of galactan was 69% ,the weight average molecular was 8700. The structural characteristics of galactan by NMR spectroscopy was showed the ct anomeric carbon of galatan took 58%, 13 anomeric carbon of galatan was 42% ;the linkage of galactan were composed of 67% 1→6 linked as the main part, 18% 1→3 linked,9. 4% 1→4 linked,5. 3% 1→2 linked.