壳聚糖羧甲基化的过程研究

Study on Carboxymethyl Ation of Chitosan and the Process

作者: 专业:工业催化 导师:冯树波 年度:2011 学位:硕士  院校: 河北科技大学

Keywords

chitosan, carboxymethyl-chitosan, solvent, DS, viscosity

        本论文研究了以有机溶剂为分散相、氢氧化钠为碱化剂、氯乙酸为改性剂、用等电点法精制制备羧甲基壳聚糖。阐述了羧甲基壳聚糖的制备方法和过程机理。较系统的从氢氧化钠用量、氯乙酸用量、醚化温度、醚化时间和有机溶剂选择这五个因素考虑,分别对产品羧甲基壳聚糖的取代度、收率、水溶性和溶解率等进行了定量的研究和分析,找到其因素影响规律。采用异丙醇为有机溶剂,通过正交实验得到羧甲基壳聚糖制备的最优工艺条件:壳聚糖5g,氢氧化钠20g,氯乙酸25g,溶胀温度30℃,溶胀时间1h,碱化温度30℃,碱化时间2h,醚化温度50℃,醚化时间4h,氯乙酸缓慢分批加入,用等电点法精制产品,在这一条件下制备的羧甲基壳聚糖的取代度为1.382,收率达85.1%,水溶性较好,并且对羧甲基壳聚糖产品的取代度、粘度、收率、溶解率和红外光谱等性能指标进行了分析和表征。羧甲基壳聚糖的传统工艺一般在非均相条件下进行,氢氧化钠和氯乙酸使用量都比较大,且原料的利用率低,对环境造成了很大的影响,加大了羧甲基壳聚糖生产成本。溶剂化效应对壳聚糖羧甲基化这一非均相系统有明显的效果,它可以提高产品性能,降低碱和酸的使用量,提高原料利用率、节约成本,在壳聚糖羧甲基化过程中逐渐受到重视,是一个非常具有应用前景的制备技术。
    In this paper, Carboxymethl-chitosan(CMC) is prepared using the organic solvent as disperse phase, the sodium hydroxide as alkalify agent, chioroacetic acid as modifier, the isoelectric for refining. The effects of reaction conditions,such as the dosage of alkali, amount ofchloroacetic acid, etherification tempreture, etherification time and organic solvent influencing degree of substitution, the yield, viscosity and dissolving rate were respectively investigated, and we got the best of conditions of preparing CMC by single factors and tests that were handed in. The optimum reaction condition are asfollows:chitosan 5g; NaOH 20g;chloroacetic acid 25g; swelling temperature 30℃;swelling time 1h;alkalize temperature 30℃;alkalize time 2h; etherification temperature 60℃; etherification time 4h; chloroacetic acid is jioned slowly;isoelectric point refined. The degree of substitution and yield of carboxymethyl chitosan can reach to 1.382 and 85.1%,water-soluble better. The O.N-CMC was analyzed and characterized by degree of substitution, viscosity, yield, dissolving rate and infrared spectrum.The conventional methods of preparing CMC were heterogeneous, more (?) ing amount of sodium hydroxide and chloroacetic acid, raw material utilization is low, to environment caused great influence, the costwas increasing. Carboxmethylation of chitosan is a non homogeneous system, using solvation has obvious effect, it can imporve product performance, reduce the use of acid and alkali, enhance raw utilization and reduce the cost, the chitisan carboxymethyl process receiving attention, which is a meaning matters of preparing.
        

壳聚糖羧甲基化的过程研究

摘要4-5
Abstract5
第1章 绪论8-15
    1.1 前言8-9
    1.2 壳聚糖及羧甲基壳聚糖9-14
        1.2.1 甲壳素来源和分布9-10
        1.2.2 壳聚糖定义及分类10-11
        1.2.3 羧甲基壳聚糖性质11
        1.2.4 羧甲基壳聚糖的应用11-13
        1.2.5 羧甲基壳聚糖的制备工艺13-14
    1.3 有机合成中的溶剂效应14
    1.4 本课题的研究目标和意义14-15
第2章 壳聚糖羧甲基化过程研究15-26
    2.1 引言15
    2.2 各类羧甲基壳聚糖的制备15-17
        2.2.1 O-羧甲基壳聚糖的制备15-16
        2.2.2 N-羧甲基壳聚糖的制备16
        2.2.3 N,O-羧甲基壳聚糖的制备16-17
    2.3 反应过程机理17-19
        2.3.1 亲核取代反应17-18
        2.3.2 壳聚糖羧甲基化机理18
        2.3.3 羧甲基壳聚糖制备各步机理18-19
    2.4 有机溶剂的选择机理19-20
    2.5 产品表征20-25
        2.5.1 脱乙酰度的测定20-21
        2.5.2 取代度的测定21-22
        2.5.3 粘度的测定22-23
        2.5.4 等电点的测定23
        2.5.5 收率的测定23-24
        2.5.6 溶解率的测定24
        2.5.7 水溶性测定24
        2.5.8 水分的测定24-25
        2.5.9 红外光谱25
    2.6 本章小结25-26
第3章 壳聚糖羧甲基化制备工艺研究26-49
    3.1 引言26
    3.2 实验部分26-29
        3.2.1 主要仪器26-27
        3.2.2 主要试剂和规格27-28
        3.2.3 反应流程28-29
    3.3 结果与讨论29-48
        3.3.1 氢氧化钠量对产品性能的影响29-33
        3.3.2 氯乙酸量对产品性能的影响33-37
        3.3.3 醚化温度对产品性能的影响37-41
        3.3.4 醚化时间对产品性能的影响41-45
        3.3.5 其它因素对实验的影响45-46
        3.3.6 正交实验与讨论46-48
    3.4 本章小结48-49
第4章 羧甲基壳聚糖制备中溶剂化效应49-59
    4.1 引言49
    4.2 实验部分49-50
        4.2.1 主要试剂49-50
        4.2.2 试验方法50
    4.3 结果与讨论50-54
        4.3.1 有机溶剂对产品性能的影响50-54
    4.4 产品表征计算54-58
        4.4.1 羧甲基壳聚糖样品取代度的计算54-56
        4.4.2 等电点的测定56
        4.4.3 产品羧甲基壳聚糖的红外图谱分析56-58
    4.5 本章小结58-59
结论59-60
参考文献60-64
硕士期间撰写和发表的文章64-65
致谢65
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