Mechanistic aspects, phase-transfer catalysis

Reactions performed under two-phase conditions are further complicated by the partitioning of the reactants and catalyst over the two phases. In the case of quaternary ammonium phase-transfer catalysis, the mechanistic aspects have received a great deal of attention (Brandstrom, 1977 Makosza, 1975 Starks and Owens, 1973). In contrast, the mechanism of crown ether-type phase-transfer catalysis has hardly been investigated at all, despite its... 

The Basic Principle of Phase-Transfer Catalysis and Some Mechanistic Aspects... 

Despite the development of phase-transfer catalysis in organic synthesis, the mechanistic aspects of phase-transfer catalysis remain obscure, due mainly to the... 

The main objective of this chapter is to illustrate how fundamental aspects behind catalytic two-phase processes can be studied at polarizable interfaces between two immiscible electrolyte solutions (ITIES). The impact of electrochemistry at the ITIES is twofold first, electrochemical control over the Galvani potential difference allows fine-tuning of the organization and reactivity of catalysts and substrates at the liquid liquid junction. Second, electrochemical, spectroscopic, and photoelectrochemical techniques provide fundamental insights into the mechanistic aspects of catalytic and photocatalytic processes in liquid liquid systems. We shall describe some fundamental concepts in connection with charge transfer at polarizable ITIES and their relevance to two-phase catalysis. In subsequent sections, we shall review catalytic processes involving phase transfer catalysts, redox mediators, redox-active dyes, and nanoparticles from the optic provided by electrochemical and spectroscopic techniques. This chapter also features a brief overview of the properties of nanoparticles and microheterogeneous systems and their impact in the fields of catalysis and photocatalysis. 

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