Schmidt Marcel, Urban Carolina, Schmidt Svenja, Schomäcker Reinhard
Department of Chemistry, Technische Universität Berlin, Str. des 17. Juni 124, Sekr. TC-8, D-10623 Berlin, Germany.
ACS Omega. 2018 Oct 17;3(10):13355-13364. doi: 10.1021/acsomega.8b01708. eCollection 2018 Oct 31.
Catalysis, particularly metal-catalyzed reactions in microemulsion systems, offers a sustainable approach for organic reactions in water. However, it is still a challenging task because of the complex role of the nonionic surfactant in such a system and the interaction of the phase behavior and reaction performance. To get a profound knowledge of this role and interaction, a systematic study of the palladium-catalyzed hydroxycarbonylation of 1-dodecene in a microemulsion system is reported. The influence of the temperature, additives such as cosolvents, the catalyst concentration, and the hydrophilicity of the surfactant and its concentration has been investigated with regard to both the phase behavior and reaction performance. Interestingly, the investigations reveal that not the phase behavior of the microemulsion system but mainly the dimension of the oil-water interface and the local concentrations of the substrates at this interface, which is provided by the amount and hydrophilicity of the surfactant, control the reaction performance of hydroxycarbonylation in these systems. Moreover, it was found that the local concentration of the active catalyst complex at the interface is essential for the reaction performance. Dependent on the surface active properties of the catalyst complex, its bulk concentration, and the nature and amount of additives, the local concentration of the active catalyst complex at the interface is strongly influenced, which has a huge impact on the reaction performance.
催化作用，尤其是微乳液体系中的金属催化反应，为水中的有机反应提供了一种可持续的方法。然而，由于非离子表面活性剂在该体系中的复杂作用以及相行为与反应性能之间的相互作用，这仍然是一项具有挑战性的任务。为了深入了解这种作用和相互作用，本文报道了在微乳液体系中对钯催化1-十二烯羟基羰基化反应的系统研究。研究了温度、助溶剂等添加剂、催化剂浓度以及表面活性剂的亲水性及其浓度对相行为和反应性能的影响。有趣的是，研究表明，控制这些体系中羟基羰基化反应性能的不是微乳液体系的相行为，而是油水界面的尺寸以及该界面处底物的局部浓度，而这是由表面活性剂的用量和亲水性决定的。此外，发现界面处活性催化剂络合物的局部浓度对反应性能至关重要。取决于催化剂络合物的表面活性性质、其本体浓度以及添加剂的性质和用量，界面处活性催化剂络合物的局部浓度会受到强烈影响，这对反应性能有巨大影响。
