【作者】 陈燕琼；

【导师】 张子勇；

【作者基本信息】 暨南大学 ， 食品科学， 2003， 硕士

【摘要】 在热色液晶中，胆甾型液晶因原料易得，价格便宜，且颜色变化鲜艳而被广泛使用。合成胆甾醇酯常用的酰氯化法存在毒性大，产率低的缺陷。 本文合成了高效酰化催化剂4-二甲基氨基吡啶(4-Dimethylamino pyridine，DMAP)，采用酰氯化法和高效酰化催化剂法分别合成了对烷氧基苯甲酸胆甾醇酯、对称脂族二羧酸胆甾醇酯、烯酸胆甾醇酯及燕尾型胆甾醇酯四类胆甾醇酯衍生物，并进行了化学结构和液晶性能的表征。然后将合成的胆甾型液晶与几种商品化的胆甾型液晶，进行混合液晶的调配与显色示温试验。考察了混合液晶组成中液晶组分对显色效果及显色温度的影响。最后，采用以明胶—阿拉伯树胶为囊壁材料的复凝聚法对配制的显色示温混合液晶进行了微胶囊化处理，并着重讨论了阿拉伯树胶的浓度及用量对液晶微胶囊粒度及显色效果的影响。 研究结果表明，高效酰化催化剂法是十分有效的酰化方法，在合成胆甾醇酯液晶中可较大幅度地提高产品的产率与纯度、简化操作、降低反应毒性。合成的10个胆甾醇酯样品中，6个具有液晶性，4个不具有液晶性。化学结构对液晶性的影响表现为：分子中引入苯环刚性结构可以提高液晶的相变温度和稳定性；脂族二羧酸胆甾醇酯中脂肪链的长度增加会降低液晶的稳定性；而末端含有燕尾结构则对液晶态的形成产生不利影响。合成的几种胆甾型液晶样品均为显色示温混合液晶组成的有益成分，分别由其配制的混合液晶颜色鲜艳，并带有珍珠般的光泽。更多还原

【Abstract】 Among general thermochromatic liquid crystals, cholesteryl ester liquid crystals have been used in showing color and displaying temperature due to their easy obtaining, low price and reversible fresh color change. There are usually some disadvantages such as more toxicity and low yield in the acetylating reaction which was used to synthesize cholesteryl ester liquid crystals.A super acylation catalyst, 4-Dimethylamino pyridine (DMAP), was prepared and used to synthesize cholesteryl ester compounds. Four kinds of cholesteryl ester compounds such as cholesteryl p-alkoxyl benzoate, cholesteryl dicarboxylate, cholesteryl lumequeic ester and coattail-like cholesteryl ester were synthesized by acylation method and super acylation catalyst method. Chemical structures and liquid crystal behaviors of the synthesized samples have been characterized by using Element Analysis, FTIR, DSC and polarized microscopy with a hot stage. The synthesized liquid crystal samples as a component were mixed with commercial cholesteryl liquid crystals to prepare thermochromatic liquid crystal mixture, respectively. Effects of different component proportions on showing color and displaying temperature of the liquid crystal mixture were studied. The cholesteryl liquid crystal mixture was microcapsulized by complex coacervation method using gelatin and acacia as membrane materials. The effects of the concentration and quantity of arabic gum on the microcapsule particle size and color showing were also studied.The research results showed that the DMAP is an effective catalyst to synthesize cholesteryl ester compounds. In the reactions, improving yield and purity, reducing toxicity as well as simplifying operation process can be carried out. For ten samples synthesized, six ones exhibit cholesteryl liquid crystal behaviors and four ones are not. Phenyl group introducing to cholesteryl ester molecules can enhance the phase transition temperatures of the liquid crystals and their stability. An increase in the chain length for cholesteryl dicarboxylate samples reduced stability of liquid crystal phases. While coattail-like structures on the ester group of the molecules have an adverse effect to form cholesteryl liquid crystal phase. Several cholesteryl liquid crystal samples synthesized are an excellent component for thermochromatic liquid crystal mixtures.更多还原