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离子液体由于其热稳定性、可设计性、低蒸汽压等优良的物化性质，正广泛应用于化学及化工的各个领域。其中最重要的应用之一就是生物质的预处理。有研究报道离子液体形成氢键的能力直接决定了其在生物质预处理中的效果，因此，寻找能与生物质形成强氢键相互作用的离子液体就成了热门的研究方向。羟乙基类离子液体由于存在单个或多个羟基，为氢键的形成提供了良好的结构基础。其合成步骤简单，无副产物生成，且成本较低，适用于大规模应用，为离子液体预处理生物质提供了可能。本文中，通过质子转移反应合成了15种羟乙基胺磺酸盐离子液体，并用核磁共振技术和红外光谱等手段对其结构和纯度进行了确证。同时，研究了它们的物化性质的变化规律，包括：熔点（Tm）、初始分解温度（Td）、密度（ρ）、粘度（η）和电导率（σ）等。结果表明，离子液体的物性与其结构，特别是阴阳离子的相互作用密切相关。此外，测定了系列离子液体在水溶液中的解离常数（pKa）。结果表明，所有离子液体的pKa均大于7，并且阳离子是决定其解离常数的关键。这些数据对于理解该类型离子液体的物性变化规律和其潜在应用具有重要的指导意义。同时，前期的研究结果表明，N-甲基二乙醇胺甲烷磺酸盐（[MDEA][mesy]）具有良好的木质素溶解能力，在生物质预处理中显示巨大的应用潜力。为了深入地了解其结构-性能关系，促进其在工业上的进一步应用，很有必要获得更多的物理化学性质数据。在本研究中，在298.15至323.15 K的温度下，研究了[MDEA][mesy]+溶剂（水、甲醇、乙醇、正丙醇和异丙醇）混合物在全摩尔组成的密度（ρ）和粘度（η）。用经验多项式方程和Vogel-Fucher-Tammen方程分别拟合了这五种二元混合物的密度和粘度数据。同时，用Redlich-Kister方程计算并关联了五种二元混合物的过量摩尔体积（VE）和粘度偏差（Δη）。此外，计算了[MDEA][mesy]和溶剂的表观摩尔体积（????）、无限稀释溶液中的表观摩尔体积以及偏摩尔体积，并从二元混合物的结构和相互作用的角度讨论了这些变化规律。1-丁基-3-甲基咪唑氯盐（[Bmim]Cl）及其二元或三元体系表现出了良好的生物质溶解效果。并且作为中间化合物，在其它更为复杂的咪唑类离子液体的合成中占有重要地位。然而离子液体标准品的缺失，给实验和定量分析带来了不小的障碍。因此，本文基于前人的研究工作，以[Bmim]Cl为研究对象，通过控制反应条件和提纯方法，最终得到了[Bmim]Cl晶体。通过X射线单晶衍射得到了其三维空间点阵及晶胞参数。通过核磁共振、傅里叶变换红外光谱和高分辨质谱等手段对其结构进行了确证，并分析了反应原料等杂质存在的可能性。利用高效液相色谱和离子滴定对其纯度进行了初步的分析，并与国内外产[Bmim]Cl进行对比，证明其HPLC峰面积比纯度大于99.5 %。该项工作为后续[Bmim]Cl标准品的制备奠定了坚实的基础。;Due to their excellent thermal and chemical properties, such as thermal stability, designability, and low vapor pressure, ionic liquids are widely used in various aspects of chemical or chemical engineering. One of the most important applications is the pretreatment of biomass. Studies have reported that the ability of ionic liquids forming hydrogen bonds directly determines their effect in biomass pretreatment. Therefore, it has became a popular research method to find ionic liquids that can form strong hydrogen bond interactions with biomass. Among them, hydroxyethylamine ionic liquids provide a good structure basis for the formation of hydrogen bonds due to the presence of single or multiple hydroxyl groups. Also, the synthesis step of this type of ionic liquids is simple, and there is no by-product formation. Thus, hydroxyethyl ionic liquids are suitable for large-scale application and show a bright prospect of industrializing biomass pretreatment. In order to get the regularities of physicochemical properties of hydroxyethylamine ionic liquids and broaden their potential application. A series of 2- hydroxyethylammonium sulfonate-based ILs were synthesized through proton transfer reaction and characterized by 1H and 13C-NMR as well as FT-IR. Their phase transfer behavior (Tm), initial decomposition point (Td), density (ρ), viscosity (η) and electrical conductivity (σ) were also characterized. In addition, the dissociation constants (pKa) of synthesized ILs in aqueous solution were obtained by acid-base titration. All these reaults were discussed basing on the structures of ILs. At the same time, N-methyl-diethanaminium methanesulfonate ([MDEA][mesy]) displayed good ability to dissolve ligin in previous work. In order to have a better understanding about the structure-property relationship and facilitate the further potential application in the industry, it is necessary to obtain more data about its physicochemical property. In this work, the densities(ρ) and viscosities(η) of [MDEA][mesy] + solvents (water, methanol, ethanol, n-propanol and isopropanol) mixtures were measured at the temperatures from (298.15 to 323.15) K in the full molar composition. The densities and viscosities data of these five binary mixtures were fitted by an empirical polynomial equation and Vogel-Fucher-Tammann (VFT) equation, respectively. Moreover, the excess molar volumes (VE) and viscosity deviation (Δη) of five binary mixtures were calculated and correlated by Redlich-Kister equation. In addition, apparent molar volumes (????), apparent molar volume in infinite dilute and partial molar volume of [MDEA][mesy] and solvents were also calculated and all these change laws were discussed in terms of the structure and interaction of binary mixtures.What’s more, 1-butyl-3-methylimidazolium chloride ([Bmim]Cl) and its binary or ternary systems also showed good biomass dissolution. As an intermediate compound, it plays an important role in the synthesis of other more complex imidazole ionic liquids. However, the absence of the ionic liquid standard has brought considerable obstacles to experimental and quantitative analysis. Therefore, in this paper, combined with the research work of the predecessors, [Bmim]Cl crystals were obtained by controlling the reaction conditions and purification methods. At the same time, the three-dimensional lattice and cell parameters were obtained by single crystal X - ray diffraction. The structures were confirmed by NMR, FT-IR and HR-MS, and the possibility of impurities in [Bmim]Cl was analyzed. The purity was analyzed by HPLC and ion titration and compared with the [Bmim]Cl produced by domestic and foreign manufacturers. The results indicated that the purity of synthesized [Bmim]Cl with the determination of HPLC peak area was more than 99.5%. This work laid the foundation for the preparation of the [Bmim]Cl standard.
|蔡光明. 生物质预处理用离子液体的制备及物性研究[D]. 中国科学院大学,2019.|
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