Synthesis Of Ionic Liquids And Their Application In The Preparation Of Nanomaterials

Ionic liquids (ILs) comprised entirely of cations and anions are liquids at room temperature, which also called low-melting salts. They are deserved for research as new types of media or"soft"functional materials, which have shown special physical and chemical properties compared with other solid or liquid materials. Due to their designable, ionic liquids are"task-specific"or"tailor-making"materials by tuning the combination between anions and cations or grafting proper functional groups. They have shown promising applications in separation and purification, reclaiming nuclear scraps, preparing special optics materials. It is one of the researching emphases in synthesis of new types and given functions of ionic liquids through molecular designing according to the special requirements.We have prepared functional ionic liquids by introducing several functional groups including allylic, ethyl-hydroxide, acetic acid, ethyl acetate into the cations of N-methylimidazole, N-methylmorpholine, N-cyanoethylimidazole, N-methyl-2-pyrrolidinonium, respectively. There are seven new types of ionic liquids which haven't been reported before, that is, 1-allyl-3-cyanoethylimidazole, N'-allyl-N-methyl-2-pyrrolidinonium, 1-2-ethylhydroxide-3-cyanoethylimidazole, N'-acetic acid-N-methylmopholine, 1-acetic acid-3-cyanoethylimidazole, N'-ethyl acetate-N-methylmorpholine, 1-ethyl acetate-3-cyanoethylimidazole. We have studied their prepared methods and characterized them by IR, 1H NMR and mass spectra (MS). Furthermore, we have tested their solubility with some solvents.The thermodynamic properties of mixtures for ionic liquid with solvents were indispensable basic data for their industrialization process. In this paper, we have studied densities and viscosities for the binary mixtures of 1-allyl-3-cyanoethylimidazolium chloride ([ACNEIm]Cl) with water from 298.15 K to 323.15 K, including their excess properties.There are many prepared methods for nanomaterials, for example, template, microemulsion, precipitation, hydrothermal or solvent-thermal, and microwave methods et al. However, some of these methods need to use volatile organic solvent or rigorous reaction conditions, which might pollute environment or increase production cost. Ionic liquids as environment-friendly green solvents have many kinds and high thermostability, which can dissolve many inorganics and organics. Therefore, they might be used to prepare nanomaterials as reaction media instead of volatile organic solvents. Searching application of ionic liquids in preparing nanomaterials will favor to develop green preparation methods which have simple technics and friendly to environment.In this work, nanostructured TiO2 particles have been synthesized at low temperature using 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM]PF6), a water immiscible room temperature ionic liquid, as an effective reaction medium by sol-gel method. The as-prepared TiO2 particles present anatase crystal morphology and have favorable photocatalytic performance even without being calcined at high temperature.In general, rutile titania is always prepared by phase transformation of TiO2 from anatase at several hundred high temperatures, which often results in particle agglomeration and grain growth. Therefore, developing a method to prepare nanorutile structure TiO2 at low temperature is of significance. In this work, we have reported a hydrolysis method at low temperature to prepare rutile titania in a carboxyl-containing ionic liquid, 1-methylimidazolium-3-acetate chlorine ([AcMIm]Cl). This method avoided high temperature and high pressure. The as-prepared rutile TiO2 also shows photocatalytic performance in the degradation of methyl orange. The template-directing performance of ionic liquid is due to the bidentate chelating complexation between the carboxylic functional group of ionic liquid and titania.Magnetic nanoparticles as a new type of materials have been extensively studied in many fields. Magnetic attractive forces combined with inherently large surface energies favor nanoparticle aggregation in magnetic dispersions. In this work, we have reported a simple method to prepare stable water-soluble iron oxide dispersions by using an ionic liquid containing acrylic acid anion, viz., N-methylimidazolium acrylic acid (MImAA) as stabilizer. The size of the as-prepared magnetite nanoparticles could be tuned from 12 nm to 20 nm depending on the concentration of MImAA in the medium. The ionic liquid can efficiently prevent interparticle aggregation and tune the particle growth.Following above work, we tried to use the prepared magnetite nanoparticle dispersion without adding other surfactants as core material for coating with silica from the hydrolyzation of tetraethyl orthosilicate (TEOS). The resulting Fe3O4/SiO2 nanocomposite has core-shell structure and the thickness of silica shell could be tuned simply by varying the concentration of TEOS precursor. The Fe3O4/SiO2/TiO2 nanocomposite have been prepared by coating Fe3O4/SiO2 with titania for its easy to magnetic separation in photocatalytic degradation of organic pollution. It has shown that its photocatalytic performance was higher than Fe3O4/TiO2 and still maintained 72 % when it was used repeating for three times.In recent years, it was increasing regards to prepare many novel microemulsions containing ionic liquid instead of water or traditional organic solvent. The influence of ionic liquids to the traditional surfactants was also arousing the chemists'attention. It was found that ionic liquids can tune critical micelle concentration (CMC) of surfactants and the amount of micellar aggregates. The hydrophilic ionic liquids can increase the CMC of surfactant and the hydrophobic ILs can decrease the CMC. Sodium dodecyl sulfate (SDS) as a traditional anionic surfactant is extensively used. It will not only pay attention to the basic chemistry but also bring larger impacts to the industry when SDS is combined with ionic liquids, and finally this will bring potential values in applications.In this work, an ionic liquid microemulsion have been prepared by combining [BMIm]PF6 with SDS, and polystyrene (PS) nanospheres have been prepared by introducing this microemulsion into traditional emulsion polymerization. As a result, we have obtained well dispersing and steady PS nanospheres with size around 70 nm.In summary, we have prepared a series of functional ionic liquids and characterized their structure including their solubility with solvents. Then we have used some ionic liquids in preparing nanomaterials. As a result, nanostructured anatase and rutile titania, stable water-soluble magnetite nanopaticels dispersions, and polystyrene nanosphere were obtained. In addition, the obtained magnetite dispersion as core materials in preparing inorganic nanocomposites also has been studied.