【作者】 侯仲轲；

【导师】 陈立功；

【作者基本信息】 天津大学 ， 应用化学， 2005， 博士

【摘要】 本文合成了一系列多元醇缩醛类化合物,探讨了其结构与凝胶性能的关系,开拓了其在制备纳米材料的实际应用。通过取代苯甲醛和山梨醇、甘露醇和木糖醇等多元醇进行缩合反应,再进一步酯化和酰化,合成了36个化合物,其中26个化合物为首次合成。化合物结构经核磁共振(NMR)和液-质联机(LC-MS)进行确认。研究发现:苯环上有吸电子基团时对缩合反应有利;多元醇缩醛衍生物6-羟基除与酰氯反应外,也能和卤代酸酯、溴代烯反应,但不与卤代烷反应;首次发现D-甘露醇与醛反应主要得到三缩合物;首次合成了含有8个羟基的对苯二甲醛和山梨醇的缩合物。大部分多元醇缩醛衍生物对含氧原子溶剂(如醇、酮、醛、醚等)可以形成稳定可逆的凝胶,最低凝胶浓度低于1w%,但对含氮原子溶剂(如胺)却不易形成凝胶;它们对脂肪醇和苯甲醚的凝胶性能显著优于环状醇、芳香醇和酮等;溶剂中少量水的加入,凝胶性能锐减;首次发现苯环上有氨基存在时,失去凝胶性能,氨基氢被芳酰基取代后又出现一定的凝胶性。应用透射电子显微镜(TEM)对有机凝胶的形态学分析表明,有机凝胶具有缠结纤维状结构,纤维直径为50-100nm,这些纤维进一步拓展为三维空间网状结构,进而形成有机凝胶;脂肪醇中形成的凝胶纤维网络最好。化合物3在丙三醇中形成的凝胶的凝胶-溶胶相转变热焓(25℃)为ΔH=55.4kJ.mol—1。应用FT-IR和X-射线衍射技术分析,发现多元醇缩醛衍生物凝胶因子是通过氢键等次价键互相作用而聚集、自我组装形成凝胶的。凝胶态呈现整体无序微区有序状态;干凝胶可以基本保持凝胶态的纤维网络结构。首次以多元醇缩醛衍生物凝胶为模板制备了纳米级二氧化硅、二氧化钛及其复合粒子。二氧化钛粒子为锐钛矿晶型,直径10-20nm,但二氧化硅粒子不呈晶态;制备的二氧化钛纳米粒子具有很好的光催化活性,对亚甲基蓝光催化降解符合一级反应动力学方程规律。更多还原

【Abstract】 In this work, a series of poly alcohol acetal derivatives as gelators weresynthesized. The relation between structure and gelation ability were studied, and theapplication of nano-material were achieved.36 compounds of were prepared by condensation between aromatic aldehyde andploy alcohol such as sorbitol,mannitol,xylitol, then esterification and acylation. Thestructure of the products have been confirmed by NMR and LC-MS. This paperindicated that it was good for condensation reaction when benzene-ring bearingelectron-attaching groups. It also showed that and the 6-hydroxyl group could bereacted with acyl halide, haloid ether and halo alkene, but not with halo alkane. It wasnot only the first time to find that the reaction product of D-mannitol and aromaticaldehyde is tri-condensation derivatives, but also the first time to obtain thep-phthaldehyde-sorbitol derivatives containing eight hydroxyl groups.The gelation ability of the poly alcohol acetal derivatives was evaluated. Itshowed that most compounds possessed the gelation abilities and formed transparentthermo-reversible gels with minimum gelation concertration of < 1w% in a widerange of organic solvents containing oxygen atom such as alcohols, ketones andethers etc. It was noted that alkyl alcohol and anisole had greater gelation ability thanaryl alcohol, cyclic alcohol and ketone. Surprisingly, the gelation ability will begreatly dropped when a little water was added in the solvent. It was found firstly thatthe compounds when benzene-ring bearing amino group would lose their gelationability.The transmission electron microscope revealed that the gels formed had afibrillar structure from about 50 to 100 nm in diameter. The fibres further formed anentangled network that was responsible for the entrapment of solvent moleculesduring gelation. The enthalpy of gel-sol phase transition by hydrogen bonding was55.4 KJ.mol-1 for compound 3 in glycerol(25℃).FT-IR studies revealed that the aggregates and self-assembly of the gelatorsoccurred as a result of cooperating non-covalent interactions such as intermolecularhydrogen-bonding. X-ray diffraction analysis illustrated that dry-gel state could keepthe fibrillar network structure of the gel state.Using organogel fibers formed by the poly alcohol acetel derivaties gelators as atemplate, the SiO2 and TiO2 nanoparticles were prepared the first time. The TiO2particles are anatase crystal form with 10-20 nm in diameter, and the SiO2 particlesare uncrystallized. The TiO2 nanoparticles have good photocatalysis degradationproperties, and the kinetics is the first-order to methylene blue.更多还原