Eric Monflier

A further breakthrough in biphasic, rhodium-catalyzed hydroformylation: the use of Per(2,6-di-O-methyl)-β-cyclodextrin as inverse phase transfer catalyst

Abstract Solvent free biphasic hydroformylalion of various water-insoluble terminal olefins can be achieved in high yields and sclcctivitics by using a water-soluble rhodium/triphenylphosphine trisulfonate catalyst and per(2,6-di-o-mclhyl)-β-cyclodcxtrin as inverse phase transfer catalyst. The catalytic activities were up to ten times higher than those observed without pcr(2,6-di-o-methyl)-β-cyclodextrin.

Remediation technologies using cyclodextrins: an overview

Nowadays, the human activity and the modern way of life are responsible for the increase of the environmental pollution. Industrial processes generate a variety of molecules that may pollute air, water, and soils due to negative impacts for ecosystems and humans. The development of innovative remediation technologies has thus emerged as a significant environmental priority. Within this scope, supramolecular chemistry, which is a recent discipline, could provide solutions. In particular, cyclodextrins (CDs) are a family of cyclic oligosaccharides having a low-polarity cavity in which organic compounds of appropriate shape and size can form inclusion complexes. This unique property makes them suitable for application in environmental protection. Here, we review the use of cyclodextrins and cyclodextrin derivatives in remediation technologies. Accordingly, the present review shows the advantages of using CDs in soil, groundwater, wastewater, and atmosphere remediation. Resulting processes are highly versatile, since the complexing ability of CD is applicable to a wide range of pollutants. They may also been referred to green processes, according to the CD innocuity. Moreover, as inclusion phenomena correspond to reversible equilibriums, a major trend in the CD environmental application field is to develop methods, which combine supramolecular chemistry and irreversible processes, as advanced oxidation or biodegradation. Such processes might lead to a complete remediation of pollutants and eventually to the CD recycling.

Supramolecular shuttle and protective agent: a multiple role of methylated cyclodextrins in the chemoselective hydrogenation of benzene derivatives with ruthenium nanoparticles

Efficient chemoselectivities have been obtained in the hydrogenation of benzene derivatives under biphasic liquid-liquid conditions using Ru(0) nanoparticles stabilized and controlled by the relevant choice of cavity and methylation degree of cyclodextrins.

Rhodium catalyzed hydroformylation of water insoluble olefins in the presence of chemically modified β-cyclodextrins: evidence for ligand-cyclodextrin interactions and effect of various parameters on the activity and the aldehydes selectivity

Abstract The biphasic rhodium catalyzed hydroformylation of water insoluble olefins in the presence of chemically modified β-cyclodextrins has been investigated. The influence of various parameters, such as the nature of the β-cyclodextrin, the concentrations of phosphine or cyclodextrin and the temperature is illustrated using 1-decene as a model substrate. The formation of inclusion complexes between the different components of the system is also discussed on the basis of NMR experiments. The results indicate that the chemically modified cyclodextrins (CyDs) must not be considered only as inverse phase transfer catalysts but also as compounds which, by trapping the water soluble ligand, can modify the equilibria between the different catalytic species.

Catalytically active nanoparticles stabilized by host-guest inclusion complexes in water.

Hydrogenation of arene derivatives can be successfully performed in water by using ruthenium(0) nanoparticles stabilized by 1 : 1 inclusion complexes formed between methylated cyclodextrins and an ammonium salt bearing a long alkyl chain.

A new, highly selective, water-soluble rhodium catalyst for methyl acrylate hydroformylation

Abstract Hydroformylation of methylacrylate to α-aldehyde can be achieved in a two-phase system in the presence of two new water-soluble phosphines. High yields and selectivities of α-aldehyde (ca. 80% with a α/β ratio of 1:20) were obtained. Spectroscopic studies have been carried out and some new rhodium complexes formed in situ in catalytic systems have been identified.

Wacker oxidation of various olefins in the presence of per(2,6-di-O-methyl)-β-cyclodextrin: mechanistic investigations of a multistep catalysis in a solvent-free two-phase system

Oxidation of various olefins into methylketones by a catalytic system constituted of palladium, copper, phosphomolybdovanadic acid and per(2,6-di-O-methyl)-β-cyclodextrin is investigated. The role of each redox catalytic system component is discussed from experiments under argon atmosphere and from vanadium NMR spectroscopic studies. The influence of various parameters, such as the per(2,6-di-O-methyl)-β-cyclodextrin concentration and the nature of the phosphomolybdovanadic acid is also reported. Finally, a catalytic cycle is also proposed.

Palladium catalyzed hydroxycarbonylation of olefins in biphasic system: beneficial effect of alkali metal salt and protective-colloid agents on the stability of the catalytic system

Abstract The addition of an alkali metal halide or a protective-colloid agent like polyvinylalcohol to water-soluble hydroxycarbonylation catalyst derived from PdCl 2 and the sulfonated phosphine TPPTS prevents the catalyst decay and allows to maintain high activities. The role of these additives is discussed in relation with the reaction mechanism.

Recent breakthroughs in aqueous cyclodextrin-assisted supramolecular catalysis

During the past twenty years, cyclodextrins (CDs) have proven to be very effective in aqueous biphasic catalysis. They could act as molecular receptors for numerous organic substrates and favour their conversion at the aqueous/organic interface. Recently, new applications have been found for CDs in aqueous catalysis. CDs can now be defined as polyfunctional entities between the substrate-containing phase and the catalyst-containing phase. In this paper, we highlight the latest breakthroughs in the use of CDs in catalysis through several examples from the literature.

Cyclodextrins as inverse phase transfer catalysts for the biphasic catalytic hydrogenation of aldehydes: a green and easy alternative to conventional mass transfer promoters

The ruthenium-catalyzed hydrogenation of water-insoluble aldehydes in an aqueous/organic two phase system has been investigated in the presence of cosolvents or cyclodextrins. At low content, i.e. a content that enables to recover quantitatively the catalytic system without loss of metal with a cosolvent, β-cyclodextrin and its dimethylated form appear to be more efficient than cosolvents for performing the reaction. The formation of inclusion complexes between cyclodextrin and various components of the reaction medium (aldehyde, alcohol, hydrocarbon of the organic phase) is discussed on the basis of mass spectrometry, NMR and catalytic experiments.