Combined impact of pH, catalyst, and strongly non-ideal solvent mixtures (SNISMs) towards boosting acid-catalyzed reactions

pH、催化剂和强非理想溶剂混合物 (SNISM) 对促进酸催化反应的综合影响

• 批准号: 525252957
• 负责人: Professor Dr.-Ing. Jakob Albert
• 金额: --
• 依托单位: Institut für Technische und Makromolekulare 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/525252957?language=en
• 关键词: Combined; impact; pH; catalyst; strongly

The interplay between reaction medium and catalyst tremendously dictates the efficiency of processes involving chemical syntheses. Homogenous catalysis requires monophasic conditions and thus, a high substrate solubility, fast kinetics, high yield, and outstanding recyclability of solvent and catalyst. Chemical reactions under elimination of water require a reaction medium that keeps thermodynamic water activity as low as possible in order to overcome yield limitations caused by thermodynamic equilibrium, while the thermodynamic reactant activity and thermodynamic catalyst activity (e.g., proton’s activity) must be as high as possible. The use of single solvents usually allows tuning only one of these properties, e.g. decreasing water activity in water-elimination reactions might be possible only at cost of decreased kinetics by negative impact on the activity of reactant or catalyst. Thus, in this project we suggest exploring strongly non-ideal solvent mixtures (SNISMs) that show pronounced negative deviations from Raoult’s law and their usefulness in reactions under elimination of water. SNISMs can be more or less hydrophilic, depending on their constituents. So far, the influence of SNISMs on the phase behavior in reaction mixtures as well as yield and kinetics of the reaction is not well known. The multifacetted influence of SNISMs on phase behaviour and reaction efficiency on top of other parameters (temperature, pressure, pH) cannot be investigated by experiments only. Thus, a predictive tool is required to gain insight into the mechanism of strongly acidic catalysts like heteropolyacids (HPAs) and to predictively tailor HPA-SNISM dream teams. These will allow catalyzing reactions under water elimination at comparably low temperatures and a tuneable separation and recycling of the catalyst. The new idea of this project is to link thermodynamic properties of the HPA-catalyst (physical interactions) and the dissociation equilibria (especially of the catalyst) with the reaction efficiency as function of the reaction media (SNISM constituents and concentrations). The dissociation equilibria and the HPA interactions will be predicted by electrolyte thermodynamic models, validated by IR characterization. We postulate that kinetic curves will fall together if the reaction velocity is related to the thermodynamic activity of the catalyst. To sum up, we aim at tailoring SNISMs for liquid-phase reactions, revealing the influence of water and of HPA-catalyst on the phase behaviour of the SNISMs and the influence of SNISMs and of HPA-catalysts on reaction thermodynamics and kinetics, and to validate predictive electrolyte models using the gathered data to finally develop predictive kinetic models. Further, we aim at establishing recyclability concepts for SNISMs and HPA-catalysts and to improve TONs, TOFs, and spacetime yield. We will validate our findings by applying the gained knowledge to another reaction system under water elimination.

反应介质和催化剂之间的相互作用极大地决定了涉及化学合成的过程的效率。均相催化需要双相条件，因此需要高底物溶解度、快速动力学、高产率以及溶剂和催化剂的突出可回收性。消除水的化学反应需要保持热力学水活性尽可能低的反应介质，以克服由热力学平衡引起的产率限制，而热力学反应物活性和热力学催化剂活性（例如，质子的活性）必须尽可能高。单一溶剂的使用通常允许仅调节这些性质中的一种，例如，在水消除反应中降低水活性可能仅以通过对反应物或催化剂活性的负面影响而降低动力学为代价。因此，在这个项目中，我们建议探索强烈的非理想溶剂混合物（SNISMs），表现出明显的负偏差拉乌尔定律和它们的有用性下消除水的反应。SNISM可以是或多或少亲水的，这取决于它们的成分。到目前为止，SNISM对反应混合物中的相行为以及反应的产率和动力学的影响还不是很清楚。SNISM对相行为和反应效率以及其他参数（温度、压力、pH）的多方面影响不能仅通过实验来研究。因此，需要一种预测工具来深入了解杂多酸（HPAs）等强酸性催化剂的机制，并预测性地定制HPA-SNISM梦之队。这些将允许在相对较低的温度下在脱水下催化反应，并对催化剂进行可调的分离和回收。该项目的新思想是将HPA-催化剂的热力学性质（物理相互作用）和解离平衡（特别是催化剂的）与作为反应介质（SNISM组分和浓度）的函数的反应效率联系起来。解离平衡和HPA相互作用将通过电解质热力学模型预测，通过IR表征验证。我们假定，如果反应速度与催化剂的热力学活性有关，则动力学曲线将落在一起。总之，我们的目标是定制SNISM的液相反应，揭示水和HPA-催化剂的SNISM的相行为的影响和SNISM和HPA-催化剂的反应热力学和动力学的影响，并验证预测的电解质模型使用收集的数据，最终开发预测的动力学模型。此外，我们的目标是建立SNISM和HPA催化剂的可回收性概念，并提高TONs，TOF和时空产率。我们将通过将所获得的知识应用于另一个反应体系下的水消除来验证我们的发现。