Organized molecular assemblies in the gas phase: reverse micelles and microemulsions in supercritical fluids

Gale, Robert W.; Fulton, John L.; Smith, Richard D.

doi:10.1021/ja00237a059

Cited by 109 publications

(64 citation statements)

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“…Stable reverse micelles of AOT large enough to accommodate aqueous solutions of proteins of significant size have been demonstrated to form in a variety of liquid alkanes (26)(27)(28)(29). Dozens of proteins, many exceeding 50 kDa in size, have been successfully solubilized by reverse micelles in organic solvents (20)(21)(22)(23)(24)(25).…”

Section: Resultsmentioning

confidence: 99%

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High-resolution NMR of encapsulated proteins dissolved in low-viscosity fluids

Wand

Ehrhardt

Flynn

1998

Proc. Natl. Acad. Sci. U.S.A.

120

167

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The majority of known proteins are too large to be comprehensively examined by solution NMR methods, primarily because they tumble too slowly in solution. Here we introduce an approach to making the NMR relaxation properties of large proteins amenable to modern solution NMR techniques. The encapsulation of a protein in a reverse micelle dissolved in a low-viscosity fluid allows it to tumble as fast as a much smaller protein. The approach is demonstrated and validated with the protein ubiquitin encapsulated in reverse micelles prepared in a variety of alkane solvents.

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Section: Resultsmentioning

confidence: 99%

“…This deviation presumably reflects differences between the effective microviscosity experienced by the reverse micelle and the viscosity of the bulk solvent as well as changes in the volume of the reverse micelle with solvent (27)(28)(29) . FIG.…”

mentioning

confidence: 99%

High-resolution NMR of encapsulated proteins dissolved in low-viscosity fluids

Wand

Ehrhardt

Flynn

1998

Proc. Natl. Acad. Sci. U.S.A.

120

167

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“…Another measure of efficiency is the minimum pressure that requires keeping the dispersion a stable single The formation of microemulsions in a scf continuous phase was first reported by Smith and co-workers using AOT in sub-and supercritical alkanes. [63] Since then, interest in surfactant/scf has grown steadily and produced a wide variety of research aimed at characterizing and applying these systems. [63][64][65] The most commonly used alkanes to form the scf continuous phase have been ethane and propane.…”

Section: Short Alkyl Chain With T-butyl Tipmentioning

confidence: 99%

“…[63] Since then, interest in surfactant/scf has grown steadily and produced a wide variety of research aimed at characterizing and applying these systems. [63][64][65] The most commonly used alkanes to form the scf continuous phase have been ethane and propane. [64] However, interest in using more environmentally benign solvents in chemical processes has pushed the forefront of surfactant/scf systems and formation of microemulsions to include CO 2 as the continuous phase.…”

Section: Short Alkyl Chain With T-butyl Tipmentioning

confidence: 99%

Synthesis and Evaluation of CO2 Thickeners Designed with Molecular Modeling

Enick¹,

Beckman²,

Johnson³

2009

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The objective of this research was to use molecular modeling techniques, coupled with our prior experimental results, to design, synthesize and evaluate inexpensive, non-fluorous carbon dioxide thickening agents.The first type of thickener that was considered was associating polymers. Typically, these thickeners are copolymers that contain a highly CO 2 -philic monomer, and a small concentration of a CO 2 -phobic associating monomer.Yale University was solely responsible for the synthesis of a second type of thickener; small, hydrogen bonding compounds. These molecules have a core that contains one or more hydrogen-bonding groups, such as urea or amide groups. Non-fluorous, CO 2 -philic functional groups were attached to the hydrogen bonding core of the compound to impart CO 2 stability and macromolecular stability to the linear "stack" of these compounds.The third type of compound initially considered for this investigation was CO 2 -soluble surfactants. These surfactants contain conventional ionic head groups and composed of CO 2 -philic oligomers (short polymers) or small compounds (sugar acetates) previously identified by our research team. Mobility reduction could occur as these surfactant solutions contacted reservoir brine and formed mobility control foams in-situ.The vast majority of the work conducted in this study was devoted to the copolymeric thickeners and the small hydrogen-bonding thickeners; these thickeners were intended to dissolve completely in CO 2 and increase the fluid viscosity. A small but important amount of work was done establishing the groundwork for CO 2 -soluble surfactants that reduced mobility by generating foams in-situ as the CO 2 +surfactant solution mixed with in-situ brine. PolymersIn this final report, we review our entire co-polymeric thickener effort and detail, for the first time, the phase behavior and viscosity results of the first non-fluorous, oxygenated hydrocarbon-based, associating polymer CO 2 thickener, poly(vinyl acetate -co -benzoyl 5% ). The CO 2 -philic monomer was vinyl acetate, and the associative thickener monomer was vinyl benzoate. Poly(vinyl acetate -co -benzoyl 5% ), Mw ~ 12000, is capable of increasing the viscosity of CO 2 by 70% at a concentration of 2wt%, a shear rate of ~5000s -1 , 298K and 9500 psia. Unfortunately, poly(vinyl acetate -co -benzoyl 5% ) is not capable of dissolving in CO 2 at pressures close to the MMP, roughly 1200 psia at 298 K. In fact, we are now convinced that a non-fluorous, hydrocarbon-based copolymeric thickener cannot be designed that will dissolve in CO 2 at typical reservoir conditions. Why? Every polymer that we designed using molecular modeling tools was indeed CO 2 soluble, a somewhat remarkable achievement given the small number of CO 2 soluble surfactants that have ever been identified, but each one was less soluble in CO 2 than poly(vinyl acetate). Therefore co-polymeric thickeners based on any CO 2 soluble polymer will undoubtedly be less soluble in CO 2 (i.e. require even greater pressures than 9500 psia)...

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“…A Tabela 1 mostra os pontos críticos para algumas substâncias com potencial aplicação como solventes supercríticos ou similares. Normalmente o ponto crítico de uma substância (temperatura e pressão críticos) aumenta com o aumento de sua polaridade (Bartscherer;Minier;Renon, 1995;Gale;Fulton;Smith, 1987), o que torna o uso de solventes supercríticos polares, como a água e a amônia, impraticável para a maioria das aplicações. Em contrapartida, o uso de fluidos apolares limita-se a algumas aplicações, devido à baixa solubilidade de compostos polares nestes fluidos, tornando necessário o uso de co-solventes ou tensoativos para auxiliar na solubilização destes compostos (Sun, 2002).…”

Section: Figura 1 -Diagrama De Fase (Plano P-t) Para O Dióxido De Carunclassified

Novos tensoativos não-iônicos para CO2-supercrítico: síntese e estudo de algumas propriedades

Cordeiro¹

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AGRADECIMENTOSEm primeiro lugar agradeço a Deus, por todas as oportunidades e conquistas proporcionadas em minha vida. Por elas sou eternamente grato.Agradeço ao Prof. Reinaldo Camino Bazito, pela orientação e convivência durante estes anos.Ao CNPq, pelo apoio financeiro, que permitiu com que me dedicasse exclusivamente ao meu projeto.Aos amigos de GPQVA e demais laboratórios, pela troca de conhecimento e experiência únicos, além de muitos momentos alegres pelos quais passamos juntos.Aos funcionários do IQ-USP pelo auxílio, direto e indireto, para que o meu projeto fosse concluído.Por último um agradecimento bastante especial aos meus pais, por todas as oportunidades que me proporcionaram e pelo seu amor, imensurável. The solubility and phase behavior of these new surfactants in sc-CO 2 were investigated, and they showed to be very soluble presenting low cloud pressures comparable to fluorinated surfactants (that are more aggressive from an environmental perspective). The polarity that these new surfactants brought to the medium was verified through the solvatochromic analysis, using the Reichardt's dye (Betaine-30) and pyrene fluorescence, which showed promising results, with polarities similar to medium chain alcohols or chlorinated solvents.

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Organized molecular assemblies in the gas phase: reverse micelles and microemulsions in supercritical fluids

Cited by 109 publications

References 0 publications

High-resolution NMR of encapsulated proteins dissolved in low-viscosity fluids

High-resolution NMR of encapsulated proteins dissolved in low-viscosity fluids

Synthesis and Evaluation of CO2 Thickeners Designed with Molecular Modeling

Novos tensoativos não-iônicos para CO2-supercrítico: síntese e estudo de algumas propriedades

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