【作者】 马娜；

【导师】 方云；

【作者基本信息】 江南大学 ， 应用化学， 2008， 硕士

【摘要】 两性表面活性剂是一类具有极高安全性,对婴儿皮肤和眼睛无刺激,生物降解性好,Krafft点低,耐硬水及高浓度电解质,无公害无污染的绿色表面活性剂。但生产过程中副产的盐分使得产品粘度过高、pH值不稳定或化学稳定性下降并影响其应用性能。目前,两性表面活性剂的纯化问题成为限制该类表面活性剂研究与应用的重要因素,所以对两性表面活性剂分离纯化的研究将为两性表面活性剂的发展起到重要推动作用。本文尝试对α–长链癸基甜菜碱(α–CB)表面活性剂进行分离纯化,重点对α–CB的电渗析脱盐进行研究,并对α–CB的表面化学性质及应用性能进行研究,主要得出以下结论:采用萃取结晶、离子交换树脂和抽提等传统方法分别对α–CB进行分离纯化。与离子交换树脂和抽提分离方法相比,萃取结晶法可以有效地去除α–CB产品中的残留脂肪酸及无机盐,并得到质量分数>98%的α–CB产品。运用红外、核磁、质谱、元素分析、熔点、测定表面张力曲线等手段对提纯后的产品进行结构鉴定和纯度检验,确定提纯后的产物为高纯度的α–癸基甜菜碱。对α–CB的电渗析脱盐进行研究,考察了操作电压、淡室流量、溶液pH值等操作条件对电渗析脱盐效果的影响,并通过比较脱盐速率、α-CB回收率和耗电量等性能指标,优化操作条件。实验证明,电渗析法可以有效脱除α–CB中的无机盐,在α–CB的等电点pH 7.50,操作电压10 V,淡室流量20 L/h的条件下,脱盐率可达到99%以上,回收率为82.7%。为进一步提高α–CB的回收率,采用恒定电流法对α–CB进行电渗析脱盐,恒定电流0.5 A,淡室流量20 L/h,溶液pH 7.50,脱盐率99%时,α–CB的回收率可以达到89.4%。对α–CB的表面化学性质和应用性能的研究表明,α–CB具有优良的表面活性和泡沫性能,其cmc值和最低表面张力(25℃)分别为9.3×10-3 mol/L和38.2 mN/m,泡沫高度可以达到175 mm;α–CB在钙皂分散和抗硬水性能方面都优于SDS,表现出了两性表面活性剂的突出优势;此外,对含有α–烷基甜菜碱的肥皂应用性能的研究表明,加入α–烷基甜菜碱后肥皂的润湿性能和抗硬水性能都有大幅提高,表现出了较强的润湿及抗硬水性能的增效作用。更多还原

【Abstract】 Zwitteronic surfactant has many excellent properties such as the low toxicity and stimulating to the skin and the eyes, good biologic degradation, low Krafft point, in addition it is able to bear the hard water and the high concentration electrolyte, basically no social effects of pollution. However, the inorganic salt producing in the zwitteronic surfactant synthesis process increases its viscosity, makes its pH not stable, decreases its stability, and effects its application performances. The difficulty purity of this surfactant limits its research and application. The separation techniques used in purification of this surfactant will promote the development of zwitteronic surfactant. In this paper, traditional purification methods were attempted to purify theα-capric betaine(α-CB). The electrodialysis desalination ofα-CB and the surface chemical properties and application performances ofα-CB were investigated. The main points were as follows:Recrystallization, ion exchange resin and extraction were applied to purify theα-CB. It was found that the fatty acid and the inorganic salt could be removed effectively by the method of recrystallization, which could be obtainedα-CB with mass fraction of 98%. Products identify and purity test were confirmed by IR, H-NMR, Ms, elemental analysis, melt point and surface tension curve.The electrodialysis desalination ofα-CB was investigated. The effects of the operation voltage, flow rate and pH of the solution on the electrodialysis desalination ofα-CB were investigated and the optimum operating condition was chosen through comparing desalination rate, the recovery ofα-CB and electricity consumption. The results showed that the inorganic salt existing in zwitterionic surfactant solution could be removed effectively. It was found that under an optimum operating condition, pH value 7.50 (at the isoelectric point ofα-CB), operation voltage 10 V, and flow rate 20 L/h, the desalination efficiency was 99% and the recovery ofα-CB was 82.7%. The electrodialysis desalination ofα-CB with constant current was investigated which made the recovery ofα-CB significantly increased. It was found that current 0.5 A, flow rate 20 L/h, pH value 7.50, the desalination efficiency was more than 99% and the recovery ofα-CB was 89.4%.The surface chemical properties and application performances ofα-CB were investigated.α-CB had good surface activity and foaming performance, the critical micelle concentration, minimum surface tension and foam height ofα-CB were tested to be 9.3×10-3 mol/L, 38.2 mN/m and 175 mm, respectively. The lime soap dispersing ability and hard water-resistance ofα-CB were superior to SDS, which exhibited excellent performance. Moreover, the application performance of soap addingα-alkyl betaine was investigated. The results showed thatα-alkyl betaine had synergism on wetting and hard water-resistance.更多还原