Organic reactions in micro-organized media: Why and how?

Ruasse, Marie‐Françoise; Blagoeva, Iva B.; Ciri, Renata; García‐Río, Luis; Leis, Jaan; Marques, António J.; Mejuto, J. C.; Monnier, Eric

doi:10.1351/pac199769091923

Cited by 42 publications

(39 citation statements)

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“…Microemulsions, which are thermodynamically stable mixtures of oil,water and surfactant, 3 are today relatively established as medium for reactions that suffer from a reactant incompatibility problem. 4 Figure 2. Profiles for the reaction between 4-tert-butylbenzyl bromide and potassium iodide performed in a two-phase system, a microemulsion, a slurry of mesoporous silica, and a hexagonal liquid crystalline phase.…”

Section: Resultsmentioning

confidence: 99%

Use of ordered mesoporous materials as tools for organic and bioorganic synthesis

Handa¹,

Witula²,

Reis³

et al. 2008

Arkivoc

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Ordered mesoporous materials are materials with well defined pore sizes in the range of 2 to 50 nm. This paper shows that suspensions of particles of mesoporous materials can be useful tools for organic and bioorganic synthesis. They can be used to overcome reactant incompatibility, as is demonstrated for a reaction between 4-tert-butylbenzyl bromide and KI. The pores are impregnated with an aqueous solution of KI and the lipophilic reactant is present in the continuous apolar phase. The reaction occurs at the pore openings. The pores of the mesoporous material can also be used as host for a homogeneous catalyst. The catalyst-loaded particles are kept as a suspension in a medium that contains the reactants. This principle is demonstrated for a Heck-type reaction with a watersoluble rhodium catalyst inserted into the pores of mesoporous silica. It is also shown to work well for a 1,4-conjugate addition between two water-soluble reactants, 4-carboxyphenylboronic acid and methyl acrylate, in which case a toluene-soluble rhodium catalyst was entrapped in the pores of hydrophobized mesoporous silica. The same principle was also used for biocatalysis. Lipase was inserted into either hydrophilic or hydrophobic pores and used for both ester synthesis and ester hydrolysis. Finally, palladium nanoparticles were deposited inside the pores of mesoporous carbon and used as catalyst for a Sonogashira reaction.

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Section: Resultsmentioning

confidence: 99%

Use of ordered mesoporous materials as tools for organic and bioorganic synthesis

Handa¹,

Witula²,

Reis³

et al. 2008

Arkivoc

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“…In earlier work on micellar effects, various scales of CTA + affinity of inorganic anions have been proposed. 22,23 These scales present simple rules based on ion exchanges at micellar interfaces. From the inspection of one of these scales, which was obtained from reactivity data 22 , the counter chloride ion appears to be less strongly bound to the surfactant head group than the carbonate ion.…”

Section: Effect Of Carbonate Concentrationmentioning

confidence: 99%

“…1 and 2 exchange equilibria at the reversed micellar interface. Since this interface is of great significant in reactivity 22,24 and is the most probable site for the luminol CL reaction 2,3 and since the micellar surface cannot be oversaturated by anions, it is postulated that the surfactant counter chloride ion is somewhat transferred from the interface to the aqueous core and thus the hydroxide ion can exist to a certain extent in the interface. When the carbonate salt is added, the counter chloride ion is to a considerable extent exchanged by the carbonate ion which is strongly CTA + -bound, so that few hydroxide ions are included in the interface.…”

Section: Effect Of Carbonate Concentrationmentioning

confidence: 99%

Reversed Micellar-Mediated Luminol Chemiluminescence Reaction with Bis(acetylacetonato)oxovanadium(IV)

et al. 1999

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“…The shape and size of the reverse micelle or the reversed micellar water pool play a significant role in the properties of reversed micellar solutions. The surfactant-water pool nanointerface provides a unique and versatile reaction field and the reversed micelles are referred to as microreactors, 16,17 which can be exploited for kinetic studies as well as analytical purposes. For example, the use of reversed micellar media in chemiluminescence (CL) analysis has been reported.…”

Section: Introductionmentioning

confidence: 99%

Adsorption Behavior of the Cetyltrimethylammonium Chloride Reverse Micelles on Porous Silica Gels

et al. 2009

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The adsorption behavior of reverse micelles of cetyltrimethylammonium chloride (CTAC) onto porous silica gels of various pore sizes has been investigated. A decrease in the amount of CTAC in the reversed micellar bulk solution in chloroform/water added to the silica gel in a column was observed, indicating the CTAC adsorption onto the silica surface. The adsorption profile obtained showed a maximum of the adsorbed surfactant amount, where the point of surface saturation may be reached, beyond which the adsorption amount remained unchanged. The adsorption of CTAC was also dependent on the specific surface area of the silica gel used. These results suggest that a CTAC monolayer may be formed and completed on the silica surface. The adsorbed CTAC amount slightly decreased with increasing the water to surfactant molar ratio, R, in the reversed micellar bulk solution, although at R < 2 the CTAC adsorption remained constant with silica gels having larger pore diameters. Even in the presence of traces of water moisture in the bulk solution used for the CTAC adsorption, the adsorption of water on silica gel was also observed and the molar ratios, RG, of the water to surfactant adsorbed on different silica gels were almost unity, implying that the silica gel may tend to hold some of water molecules originally adsorbed on its surface. The adsorption of CTAC molecules appears to occur through the adsorbed water molecules, probably polarized at the silica surface, and a CTAC-water-silica nanointerface seems to be formed. The adsorbed water amount or RG also increased with an increase in R and on silica gels with larger pore diameters and a plateau was observed in the R range of 3 -4, beyond which an increase in RG occurred again. The water molecules present in the vicinity of the adsorbed CTAC and the silica surface may possess different properties at different R and RG values.

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Organic reactions in micro-organized media: Why and how?

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Cited by 42 publications

References 0 publications

Use of ordered mesoporous materials as tools for organic and bioorganic synthesis

Use of ordered mesoporous materials as tools for organic and bioorganic synthesis

Reversed Micellar-Mediated Luminol Chemiluminescence Reaction with Bis(acetylacetonato)oxovanadium(IV)

Adsorption Behavior of the Cetyltrimethylammonium Chloride Reverse Micelles on Porous Silica Gels

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