摘要
采用了常规直接酰化、相转移催化酰化（相转移催化剂分别为四丁基溴化铵和18-冠醚-6）和离子交换-酰化法对3种小分子量（-3、-5和-10kDa）κ-卡拉胶进行乙酰化．常规直接酰化法获得产品的酰化度很低；相转移催化酰化法中以18-冠醚-6为催化剂时酰化度较高，适宜制备较低分子量（如-3和-5kDa）且酰化度为中等以下的κ-卡拉胶；离子交换-酰化法所得产品的酰化度最高，但因制备路线长，适合较大分子量（如-10kDa）κ-卡拉胶的酰化．红外光谱和^13C—NMR证实乙酰基优先接入G6位伯羟基上，其次才接入G2和A2位的仲羟基上．
Acetylation of low-molecular-weight κ-carrageenans （about 3, 5 and 10 kDa） was performed using three methods-conventional direct acylation, phase transfer catalysis acylation and ion exchange - acylation, respectively. The experimental results show that conventional direct acylation gave products with very low acylation substitution degree （ASD）. Acetylation using 18 - crown - 6 as phase transfer catalyst can yield much higher ASD products and is suitable for preparing lower - molecular - weight acylated κ-carrageenan with medium or less ASD. Ion exchange - acylation can produce acylated κ-carrageenan with the highest ASD among the throe methods. However, the route for ion exchange - acylation is a little complex and is only recommended for acylation of larger- molecular- weight κ-carrageenan. IR and ^13C - NMR analyses of acylated κ-carrageenan indicate that acetyl has been connected with κ-carrageenan and acetyl is preferentially connected with the primary hydroxyl groups, and then with the secondary hydroxyl groups.
出处
《福州大学学报（自然科学版）》
CAS
CSCD
北大核心
2006年第5期755-759,765,共6页
Journal of Fuzhou University(Natural Science Edition)
基金
福建省自然科学基金资助项目(C0310007)
福建省科技三项基金资助项目(K02014)
关键词
小分子量κ-卡拉胶
乙酰化
相转移催化
离子交换
low-molecular-weight κ-carrageenan
acetylation
phase transfer catalysis
ion exchange
