Characterization of the Properties and Phase Behavior of nonionic Surfactants confined in mesoporous Silica Materials employing Solid State NMR Techniques

采用固态核磁共振技术表征介孔二氧化硅材料中非离子表面活性剂的性能和相行为

• 批准号: 278867442
• 负责人: Professor Dr. Gerd Buntkowsky
• 金额: --
• 依托单位: Fachgebiet Physikalische Chemie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/278867442?language=en
• 关键词: Characterization; Properties; Phase; Behavior; nonionic

Polyethylene glycol (PEG) and related CmEn-type nonionic surfactants contain a variety of favorable properties (low vapor pressure, non-toxicity, biodegradability etc.) that enable them to be used as green solvents for chemical reactions. In addition, they can be applied in supported liquid phase systems, where they are embedded in a mesoporous silica matrix. To fully exploit their potential as solvents, it is necessary to understand their physicochemical properties, their interactions with the support surface, and their phase behavior in the confinement of the pores. Preliminary molecular dynamics (MD) studies of neat PEG as well as experimental solid-state NMR (ssNMR) and thermodynamic studies of PEG under confinement have illustrated the importance of intra- and intermolecular hydrogen bonding interactions in PEG and CmEn-type surfactants for understanding their interactions with pore surfaces. To further discern the details of these intra- and intermolecular interactions, ssNMR, thermodynamic and MD simulation studies will be carried out on model molecules that possess structures derived from 1-octanol (C8E0). With these models, firstly the effect of the placement of an ether functional group in the 1-octanol base structure on the intra- and intermolecular hydrogen bonding behavior will be inspected. Secondly, differences between nonionic surfactants with linear and branched alkyl chains in their behavior under confinement will be studied. The confinement will be mimicked by a systematic set of functionalized porous materials, to elucidate the interactions of the confined molecules with the surface functionalization present in Pd catalysts immobilized onto mesoporous silica through vanillin and aminopropyltriethoxysilane (APTES) surface decorations. The combined results from these studies will provide detailed molecular level insights about the reaction environment in heterogeneous transition metal catalysis using PEG and CmEn-type nonionic surfactants as the reaction medium.

聚乙二醇（PEG）及相关的CmEn型非离子表面活性剂具有低蒸气压、无毒、可生物降解等优点。这使得它们能够用作化学反应的绿色溶剂。此外，它们可以应用于负载液相系统，其中它们嵌入在介孔二氧化硅基质中。为了充分利用它们作为溶剂的潜力，有必要了解它们的物理化学性质，它们与载体表面的相互作用，以及它们在孔限制中的相行为。初步的分子动力学（MD）研究的净PEG以及实验固态NMR（ssNMR）和热力学研究的PEG约束下，说明了分子内和分子间氢键相互作用的重要性，在PEG和CmEn型表面活性剂了解它们与孔表面的相互作用。为了进一步辨别这些内部和分子间相互作用的细节，ssNMR，热力学和MD模拟研究将进行具有衍生自1-辛醇（C8 E0）的结构的模型分子。利用这些模型，首先将考察1-辛醇基结构中醚官能团的位置对分子内和分子间氢键行为的影响。其次，将研究具有直链和支链烷基链的非离子表面活性剂在受限条件下的行为差异。的限制将模仿由一组系统的功能化多孔材料，阐明的相互作用的限制分子与表面功能化存在于Pd催化剂固定到介孔二氧化硅通过香草醛和氨丙基三乙氧基硅烷（APTES）表面装饰。从这些研究的综合结果将提供详细的分子水平的见解，在多相过渡金属催化剂使用PEG和CmEn型非离子表面活性剂作为反应介质的反应环境。