Palladium-Catalyzed Hydroxycarbonylation of 1-Dodecene in Microemulsion Systems: Does Reaction Performance Care about Phase Behavior?

Abstract

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.

Rh-Catalyzed Reductive Amination of Undecanal in an Aqueous Microemulsion System Using a Non-Ionic Surfactant

“…Undeniably, the separation of the dissolved catalyst from the products is the biggest challenge for homogeneous catalysis. There are several approaches available for the separation and reuse of the homogeneous catalyst, e.g., a simple biphasic system [8] or so-called switchable solvent systems, like switchable-hydrophilicity solvents (SHS [9,10]), thermomorphic systems (TMS [11,12]), and microemulsion systems (MES [13,14]). The homogeneously catalyzed reductive amination of aldehydes using aqueous media has also been described in the literature [15][16][17].…”

Ionic Liquids as Surfactants in Aqueous Multiphase Systems for the Pd‐Catalyzed Hydrocarboxylation

“…The determined CMC values confirm the assumed surface activity of the examined ionic liquids and so the ionic liquids may behave like a surfactant. As known from the literature, the surfactant concentration is crucial for the phase behavior and so for the local concentrations at the interfacial area 11. The influence of different ionic liquids and their concentrations on the hydrocarboxylation of 1‐dodecene and the subsequent phase separation of the reaction mixture is shown in Fig.…”

“…phase behavior and so for the local concentrations at the interfacial area [11]. The influence of different ionic liquids and their concentrations on the hydrocarboxylation of 1-dodecene and the subsequent phase separation of the reaction mixture is shown in Fig.…”

“…Numerous examples of multiphasic recyclable carbonylation reactions are given in the literature. The hydroformylation of 1-dodecene can be promoted using the ionic surfactant cetyltrimethylammonium bromide (CTAB) [9] whereas nonionic surfactants (e.g., alkyl polyethylene glycol ethers) are successfully used for the hydroformylation and hydrocarboxylation of 1-dodecene [10,11]. Porada et al described the amphiphilic character of ionic liquids like alkylmethylimidazolium salts and their ability to form the described microemulsions [12].…”

Palladium-Catalyzed Selective Amino- and Alkoxycarbonylation of Iodoarenes with Aliphatic Aminoalcohols as Heterobifunctional O,N-Nucleophiles

“…Among the broad scope of nucleophiles such as alcohols and phenols, , amines, thiols, or even water and selenols, O- and N-nucleophiles have been the most extensively studied for the manufacturing of the corresponding esters and amides that are significantly important in fine chemical and pharmaceutical industries . While several studies have been reported for the utilization of simple amines and alcohols as model substrates, only a few works focused on the investigation of carbonylation reactions in the presence of homobifunctional and even heterobifunctional nucleophiles.…”