衍生化气相色谱-质谱法分析羟丙基瓜尔胶的取代分布  

Analysis of substitution distribution of hydroxypropyl Guar gum by derivatization and gas chromatography-mass spectrometry

作　　者：巩沛鑫 叶应庆 陈卫平 彭树华 季美芳 GONG Pei-xin;YE Ying-qing;CHEN Wei-ping;PENG Shu-hua;JI Mei-fang(Kunshan Jingkun Chemistry Company,Kunshan,Kunshan 215300,China)

机构地区：[1]昆山京昆油田化学科技有限公司,江苏昆山215300

出　　处：《化学研究与应用》2022年第10期2449-2454,共6页Chemical Research and Application

摘　　要：羟丙基瓜尔胶是瓜尔胶与环氧丙烷在碱性条件下发生醚化反应得到的一种瓜尔胶衍生物,羟丙基的取代度及取代分布与羟丙基瓜尔胶的性能和应用是密切相关的。本文采用甲基化、水解、还原、乙酰化的衍生化技术,通过气相色谱质谱分析了五种不同取代度的羟丙基瓜尔胶的取代分布。发现随着取代度的增加,未取代单元的比例逐渐减少,双取代比例逐渐增加,单取代单元的比例先增加后减少,最高到46.66%。通过MS/DS可以计算平均链长,发现随着取代度的增大,平均链长略有增加,但DPn值都很小,说明羟丙基上的羟基活性很低,难以再与环氧丙烷反应,形成长链结构。Hydroxypropyl Guar gum(HPG)is a derivative of Guar gum,obtained by etherification with propylene oxide under alkaline conditions.The degree and distribution of hydroxypropyl substitution are closely related to the reactivity of hydroxyl groups,but there are few reports on the reactivity of hydroxyl groups in different positions of Guar gum.In this paper,the substitution distributions of HPG with different degrees of substitution were analyzed by Gas chromatography-mass spectrometry using derivatization technique。With the increase of degree of substitution,the proportion of unsubstituted units decreases gradually,the proportion of double substituted units increases gradually,and the proportion of single substituted units increases first and then decreases,up to 46.66%.The average chain length can be calculated by MS/DS.With the increase of substitution degree,the average chain length increases slightly,but the DPn value is very small,indicating that hydroxyl on hydroxypropyl group has low activity,and it is difficult to react with epoxy propane to form a long chain structure.

关 键 词：羟丙基瓜尔胶 衍生化 气相色谱质谱 取代分布 平均链长 

分 类 号：O636.1[理学—高分子化学]