Showing papers on "Solvent published in 2003"

Solvent compatibility of poly(dimethylsiloxane)-based microfluidic devices.

Abstract: This paper describes the compatibility of poly(dimethylsiloxane) (PDMS) with organic solvents; this compatibility is important in considering the potential of PDMS-based microfluidic devices in a number of applications, including that of microreactors for organic reactions. We considered three aspects of compatibility: the swelling of PDMS in a solvent, the partitioning of solutes between a solvent and PDMS, and the dissolution of PDMS oligomers in a solvent. Of these three parameters that determine the compatibility of PDMS with a solvent, the swelling of PDMS had the greatest influence. Experimental measurements of swelling were correlated with the solubility parameter, δ (cal1/2 cm-3/2), which is based on the cohesive energy densities, c (cal/cm3), of the materials. Solvents that swelled PDMS the least included water, nitromethane, dimethyl sulfoxide, ethylene glycol, perfluorotributylamine, perfluorodecalin, acetonitrile, and propylene carbonate; solvents that swelled PDMS the most were diisopropylam...

A nanoporous molecular magnet with reversible solvent-induced mechanical and magnetic properties

Abstract: A nanoporous molecular magnet with reversible solvent-induced mechanical and magnetic properties

Solvent properties of the 1-butyl-3-methylimidazolium hexafluorophosphate ionic liquid

Abstract: 1-Butyl-3-methylimidazolium hexafluorophosphate (BMIM-PF6) was synthesized and purified to be used as a ionic liquid solvent. Its physicochemical properties were studied. The ionic liquid/water (P il/water) and ionic liquid/heptane (P il/heptane) distribution coefficients of a set of 40 compounds with various functionalities, including organic acids, organic bases, amino acids, antioxidants, and neutral compounds, were measured using liquid chromatography. For ionizable compounds, the P il/water values measured at pH 2, 5.1, and 10 were very different. These allowed the determination of both the molecular Poil/water values and the ion P−il/water value for each compound. These coefficients were compared to the corresponding P oct/water coefficients. Marked differences in the partitioning behavior of basic, acidic, and neutral compounds were observed. The relationship between P il/water and P oct/water is different from that reported previously. By using the linear free energy solvation approach and the descriptors found for 12 solutes, the BMIM-PF6 solvent parameters were calculated for the ionic liquid/water and ionic liquid/heptane biphasic systems. The regression parameters show a low basicity of the BMIM-PF6 solvent compared to octanol. The high cohesion of the ions in the ionic liquid phase is also indicated by the regression equations obtained. Ionized phenols (phenoxide ions) associate more strongly with BMIM-PF6 than most other ionized molecules. Amino acids were not soluble in ionic liquid; however, it is possible to extract them partially by adding a crown ether to the ionic liquid phase and working at pH 1. The positive form of amino acids is complexed by the crown ether and the complex is extracted in the ionic liquid phase.

Degradation pathways for monoethanolamine in a CO2 capture facility

Abstract: One of the highest priorities in carbon sequestration science is the development of techniques for CO2 separation and capture, because it is expected to account for the majority of the total cost (∼75%). The most common currently used method of CO2 separation is reversible chemical absorption using monoethanolamine (MEA) solvent. In the current study, solvent degradation from this technique was studied using degraded MEA samples from the IMC Chemicals Facility in Trona, California. A major pathway to solvent degradation that had not been previously observed in laboratory experiments has been identified. This pathway, which is initiated by oxidation of the solvent, is a much more significant source of solvent degradation than the previously identified carbamate dimerization mechanism.

Metal-free, noncovalent catalysis of diels-alder reactions by neutral hydrogen bond donors in organic solvents and in water.

Abstract: We examined the catalytic activity of substituted thioureas in a series of Diels–Alder reactions and 1,3-dipolar cycloadditions. The kinetic data reveal that the observed accelerations in the relative rates are more dependent on the thiourea substituents than on the reactants or solvent. Although the catalytic effectiveness is the strongest in noncoordinating, nonpolar solvents, such as cyclohexane, it is also present in highly coordinating polar solvents, such as water. In 1,3-dipolar cycloadditions, the thiourea catalysts demonstrate only very moderate selectivity for reactions with inverse electron demand. Our experiments emphasize that both hydrophobic and polar interactions can co-exist, making these catalysts active, even in highly coordinating solvents. This class of catalysts increases the reaction rates and endo-selectivities of Diels–Alder reactions, in a similar manner to weak Lewis acids, without concomitant product inhibition.

Direct synthesis of hydrogen peroxide from H2 and O2 using Pd and Au catalysts

Abstract: The direct synthesis of hydrogen peroxide from H2 and O2 using a range of supported metal catalysts is described and discussed. A detailed study of the factors influencing the formation and decomposition of hydrogen peroxide is presented for a Pd/sulfonated carbon catalyst in a methanol/water solvent. The use of low temperatures (1–2 °C) and short reaction (residence) time are identified as the key factors that favour high selectivity to hydrogen peroxide. Decomposition of hydrogen peroxide, mainly via further hydrogenation, prevents the formation of high concentrations of hydrogen peroxide. Combustion of hydrogen to water is a competing reaction that becomes significant at higher temperatures, but this can be partially inhibited by the addition of HBr. A second set of supported Pd and Au catalysts are evaluated for the direct synthesis of hydrogen peroxide using supercritical CO2 as a solvent. The use of supercritical CO2 is shown to be beneficial when compared with hydrogen peroxide formation at a temperature just below the critical temperature for CO2. However, at the critical temperature of CO2 (31.1 °C), the decomposition of hydrogen peroxide is rapid and only low rates of hydrogen peroxide formation are observed. At low temperature (2 °C) supported Au catalysts are shown to be very selective for the synthesis of hydrogen peroxide. The rate of hydrogen peroxide synthesis is enhanced markedly when Pd is present with Au and a detailed scanning transmission electron microscopy study shows that the 2–9 nm metal nanoparticles present in this supported catalyst are a Au∶Pd alloy.

Solubility enhancement of Cox-2 inhibitors using various solvent systems.

Abstract: This study examined the solubility enhancement of 4 cox-2 inhibitors, celecoxib, rofecoxib, meloxicam, and nimesulide, using a series of pure solvents and solvent mixtures Water, alcohols, glycols, glycerol, and polyethylene glycol 400 (PEG 400) were used as solvents and water-ethanol, glycerol-ethanol, and polyethylene glycol-ethanol were used as mixed-solvent systems A pH-solubility profile of drugs was obtained in the pH range 70 to 109 using 005M glycine-sodium hydroxide buffer solutions Lower alcohols, higher glycols, and PEG 400 were found to be good solvents for these drugs The aqueous solubility of celecoxib, rofecoxib, and nimesulide could be enhanced significantly by using ethanol as the second solvent Among the mixed-solvent systems, PEG 400-ethanol system had highest solubilization potential In the case of meloxicam and nimesulide, solubility increased significantly with increase in pH value Physico-chemical properties of the solvent such as polarity, intermolecular interactions, and the ability of the solvent to form a hydrogen bond with the drug molecules were found to be the major factors involved in the dissolution of drugs by pure solvents The greater the difference in the polarity of the 2 solvents in a given mixed solvent, the greater was the solubilization power However, in a given mixed-solvent system, the solubilization power could not be related to the polarity of the drugs Significance of the solubility data in relation to the development of formulations has also been discussed in this study

Continuous flow hydroformylation of alkenes in supercritical fluid-ionic liquid biphasic systems.

Abstract: A process for the hydroformylation of relatively low volatility alkenes (demonstrated for 1-dodecene) in a continuous flow system is described The catalyst is dissolved in an ionic liquid while the substrate and gaseous reagents are transported into the reactor dissolved in supercritical CO2, which simultaneously acts as a transport vector for aldehyde products Decompression of the fluid mixture downstream yields products which are free of both reaction solvent and catalyst The use of rhodium complexes of triaryl phosphites leads to ligand degradation through reaction of the ionic liquid with water and subsequent attack of the released HF on the phosphite Sodium salts of sulfonated phosphines are insufficiently soluble in the ionic liquids to obtain acceptable rates, but replacing the sodium by a cation similar to that derived from the ionic liquid, allows good solubility and activity to be obtained The nature of the ionic liquid is very important in achieving high rates, with 1-alkyl-3-methylimidazo

Elimination of oxidative degradation during the per-O-methylation of carbohydrates.

Abstract: The possible oxidative degradation mechanism occurring during the per-O-methylation of carbohydrates in dimethyl sulfoxide with methyl iodide in the presence of base is described. Evidence is presented that this process occurs only under anhydrous conditions when there is a long reaction time between the carbohydrate dissolved in dimethyl sulfoxide and methyl iodide, followed by reaction with the base. Under these specific conditions, the oxidative degradation of alditols, and cyclic carbohydrates, with and without a free hemiacetal group, is observed. The reaction between carbohydrate and methyl iodide in dimethyl sulfoxide can result in a complete oxidative degradation depending on the type of carbohydrate and the time of reaction. The oxidative degradation can be accelerated by replacing methyl iodide with dimethyl sulfate. Mass spectrometric identification of the degradation products of d-glucitol indicates simultaneous oxidation processes at all the hydroxyl groups, with site dependent rates of their reactivity. This oxidative process is not a characteristic of the methylation of carbohydrates in dimethyl sulfoxide with methyl iodide in the presence of solid sodium hydroxide and can be totally avoided by treating the carbohydrate with powdered sodium hydroxide before introduction of methyl iodide under nonanhydrous conditions, or by adding a trace of water in dimethyl sulfoxide before methyl iodide, or by using N,N-dimethylacetamide as the solvent. The degradation of the per-O-methylated carbohydrates in the liquid-liquid extraction process is also taken into account, and it is found that the degradation process can be avoid by neutralization of the base before extraction, by using benzene or tetrachloromethane as extraction solvent, and by drying the final organic extract.

Ionic liquids as a novel solvent for lanthanide extraction

Abstract: Octyl(phenyl)-N,N-diisobutylcarbamoylmethyl phosphine oxide (CMPO) dissolved in an ionic liquids, 1-butyl-3-methylimidazolium hexafluorophosphate, greatly enhances extractability and selectivity of lanthanide cations compared to that dissolved in conventional organic solvents; further, the recovery of lanthanides extracted into ionic liquids can be accomplished using several stripping solutions containing complexing agents The possibility of utilizing ionic liquids as novel separation media in an industrial liquid-liquid extraction process was demonstrated

Reactivities of Some Electrogenerated Organic Cation Radicals in Room-Temperature Ionic Liquids: Toward an Alternative to Volatile Organic Solvents?

Abstract: Four different ionic liquids, based on 1-alkyl-3-methylimidazolium or quaternary ammonium cations, were used as reaction media for several typical electrochemical reactions with a strict control of the residual water concentration. The oxidation of organic molecules (anthracene, naphthalene, durene, 1,4-dithiafulvene, and veratrole) for which the cation radicals undergo first and second-order kinetics reactions were investigated in ionic liquids and compared with their behavior in acetonitrile. From the analysis of the voltammetric current responses, the reaction mechanism was established and the thermodynamic and kinetics parameters were extracted. The most interesting result is that the nature of investigated mechanisms is almost unchanged in ionic liquids as compared with conventional organic media. A decrease of the electron-transfer kinetics from the aromatic molecules to the electrode (around 1 order of magnitude) is observed for all of the studied molecules, indicating an higher solvent reorganizat...

Rapid and amenable suzuki coupling reaction in water using microwave and conventional heating.

Abstract: It is possible to prepare biaryls in good yield very rapidy (5-10 min) on small (1 mmol) and larger (10-20 mmol) scales from aryl halides and phenylboronic acid using water as a solvent and palladium acetate as catalyst. The reaction can be performed equally well using microwave and conventional heating, showing that using these conditions probably no nonthermal microwave effects are associated with the impressive speed of the reaction.

Microstructuring by printing and laser curing of nanoparticle solutions

Abstract: In this letter, the process of printing and laser curing of nanoparticle solutions is presented A liquid solvent is employed as the carrier of gold nanoparticles (the material of interest in this study) possessing a low melting temperature compared to that of bulk gold Using a specifically designed printing system, the gold nanoparticle solution is deposited on a substrate and cured with laser radiation In this manner, the potential of writing gold structures on temperature sensitive substrates is demonstrated The interaction between the laser radiation and nanoparticles drives the solvent evaporation and controls the quality of the microstructures printing process The latter is also affected by thermocapillary flow at the free surface, developing during the curing process An optical method for estimating the curing times is also developed and discussed

Formation and properties of anchored polymers with a gradual variation of grafting densities on flat substrates

Abstract: We show that assemblies comprising anchored polymers with a gradual variation of grafting densities on solid substrates can be generated by first covering the substrate with a molecular gradient of the polymerization initiator, followed by polymerization from the substrate-bound initiator centers (“grafting from”). We apply this technique to prepare grafting density gradients of poly(acrylamide) (PAAm) on flat silica substrates. We demonstrate that using the grafting density gradient geometry, the mushroom-to-brush transition can be accessed on a single sample. This transition is detected by monitoring the dependence of the thickness of the grafted PAAm in a good solvent using variable angle spectroscopic ellipsometry. Wettability experiments performed on the gradient PAAm substrate provide complementary information about the nature of the mushroom-to-brush transition.

Supercritical Fluid Extraction of a Nonionic Surfactant Template from SBA-15 Materials and Consequences on the Porous Structure

Abstract: SBA-15 mesoporous materials were synthesized using the method reported by Zhao et al. Surfactant was removed from as-made materials by means of different techniques: thermal treatment under air atmosphere, solvent washing at different temperatures, and supercritical CO2 extraction in the presence and absence of cosolvents. The structure of resulting materials was characterized using conventional techniques: nitrogen and argon adsorption measurements, powder X-ray diffraction (XRD), thermogravimetric analysis (TGA), infrared spectroscopy (FT-IR), and 29Si MAS NMR. The efficiency of surfactant removal using CO2 under supercritical conditions is similar to that obtained by means of solvent washing under reflux but shows some improvements in the presence of cosolvents. Mesoscopic properties of mild-temperature solvent extracted SBA-15 materials depend on the efficiency of the surfactant removal and the use of supercritical CO2 as solvent. Likewise, the size and volume of the complementary microporosity dete...

Fluorous catalysis under homogeneous conditions without fluorous solvents: a "greener" catalyst recycling protocol based upon temperature-dependent solubilities and liquid/solid phase separation.

Abstract: The thermomorphic fluorous phosphines P((CH2)m(CF2)7CF3)3 (m = 2, 1a; m = 3, 1b) exhibit ca. 600-fold solubility increases in n-octane between −20 (1a = 0.104 mM) and 80 °C (63.4 mM) and 1500-fold solubility increases between −20 and 100 °C (151 mM). They catalyze conjugate additions of alcohols to methyl propiolate under homogeneous conditions in n-octane at 65 °C and can be recovered by simple cooling and precipitation and used again. This avoids the use of fluorous solvents during the reaction or workup, which are expensive and can leach in small amounts. Teflon shavings can be used to mechanically facilitate recycling, and 31P NMR analyses indicate >97% phosphorus recovery (85.2% 1a, 12.2% other). 19F NMR analyses show that 2.3% of the (CF2)7CF3 moieties of 1a leach, in some form, into the n-octane (value normalized to phosphorus). 1a similarly catalyzes additions in the absence of solvent. Yield data match or exceed those of reactions conducted under fluorous/organic liquid/liquid biphase conditions....

Headspace liquid-phase microextraction of chlorobenzenes in soil with gas chromatography-electron capture detection

Abstract: The organic solvent film formed in a microsyringe barrel was used as an extraction interface in headspace liquid-phase microextraction (HS-LPME) of chlorobenzenes. Some common organic solvents with different vapor pressures (9.33-12 918.9 Pa) were studied as extractants. The results indicated that even the solvent with the highest vapor pressure (cyclohexane) can be used to carry out the extraction successfully. In general, the reasons for successful extraction are the very small space (5 mm3) within the microsyringe barrel and the fast equilibrium between gaseous analytes and organic solvent film. Both of these factors significantly reduced the risk of solvent loss during extraction. Thus, the choice of extraction solvent for the present method was very flexible. From the viewpoint of extraction efficiency, toluene (which has relatively low vapor pressure) was found to provide the best extraction efficiency. The effects of sampling volume, organic solvent volume, syringe withdrawal rate, and number of extraction cycles were also investigated. The procedure with respect to repeatability and limits of detection was evaluated by soil spiked with chlorobenzenes. Repeatabilitywas between 5.7 and 17.7%, and the limits of detection were 6-14 ng/g. HS-LPME was shown to be an inexpensive, fast, and simple sample preparation method for volatile compounds.

Stability of divalent europium in an ionic liquid: Spectroscopic investigations in 1-methyl-3-butylimidazolium hexafluorophosphate

Abstract: In this work, devoted to 1-methyl-3-butylimidazolium hexafluorophosphate ionic liquid (BumimPF 6), the importance of the purity of the solvent for spectroscopic investigations is highlighted. Results from small angle X-ray scattering indicate that the pure solvent exhibits a local organization. Europium(II), which appears to be unusually stable in BumimPF 6 , is characterized by spectroscopic techniques (absorption, luminescence). Solvation of Eu(II) in BumimPF 6 and complexation effects in the presence of the crown ether 15C5 solubilized in the ionic liquid are discussed.

Decomposition of LiPF6and Stability of PF 5 in Li-Ion Battery Electrolytes Density Functional Theory and Molecular Dynamics Studies

Abstract: The decomposition of and the stability of in organic solvents, diethyl carbonate (DEC), dimethyl carbonate (DMC), γ-butyrolactone (GBL), and ethylene carbonate (EC), have been investigated through density functional theory (DFT) calculations, in which solvent was modeled as a dielectric continuum, and also by molecular dynamics (MD) simulations which treated solvents explicitly. Both calculations showed a similar trend in which the decomposition was further promoted in more polar solvents, yet the DFT calculations predicted an endothermic decomposition, while the MD simulations indicated exothermic. This sharp contrast in the results suggests strong solute-solvent interactions, especially for which were not accounted for in the DFT calculations. The specific interaction between and solvent was further investigated by DFT calculations for adduct models and also by the MD simulations for solutions. Both calculations suggest a stable formation of a -solvent adduct in solution and its stability depends on the solvent. It was found that is more stabilized in polar and sterically compact solvents such as EC and GBL than in less polar and bulky, linear carbonates such as DMC and DEC. The reactivity of with organic solvents and the difference in the stability of between organic and aqueous solution are also discussed. © 2003 The Electrochemical Society. All rights reserved.

Pressurized liquid extraction of polar and nonpolar lipids in corn and oats with hexane, methylene chloride, isopropanol, and ethanol

Abstract: Samples of freshly ground corn kernels and freshly ground rolled oats were extracted via pressurized liquid extraction (accelerated solvent extraction) using four different organic solvents [hexane, methylene chloride (also known as dichloromethane), isopropanol, and ethanol] at two temperatures (40 and 100°C). Lipid yields varied from 2.9 to 5.9 wt% for ground corn and from 5.5 to 6.7 wt% for ground oats. With ground corn, more lipid was extracted as solvent polarity was increased, and for each individual solvent, more lipid was extracted at 100°C than at 40°C. With ground oats, the same temperature effects was observed, but the solvent polarity effect was more complex. For both corn and oats, methylene chloride extracted the highest levels of each of the nonpolar lipid classes. In general, for both corn and oats, icnreasing solvent polarity resulted in increasing yields of polar lipids, and for each solvent, more of each lipid class was extracted at 100°C, than at 40°C. Among the lipids in corn extracts, the phytosterols may be the most valuable, and total phytosterols ranged from about 0.6 wt% in the hot ethanol extracts to about 2.1 wt% in the hot hexane and methylene chloride extracts. Total phytosterols in all oat extracts were about 0.1 wt%. Digalactosyldiacylglycerol was the most abundant polar lipid in the oat extracts; its levels ranged from 1.6 wt% in the cold hexane extracts to 4.3 wt% in the hot ethanol extracts.

Chemistry In Alternative Reaction Media

Abstract: Preface.Abbreviations and Acronyms.1 Chemistry in Alternative Reaction Media.1.1 Economic and Political Considerations.1.2 Why Do Things Dissolve?1.3 Solvent Properties and Solvent Classification.1.3.1 Density.1.3.2 Mass Transport.1.3.3 Boiling Point, Melting Point and Volatility.1.3.4 Solvents as Heat-Transfer Media.1.3.5 Cohesive Pressure, Internal Pressure, and Solubility Parameter.1.4 Solvent Polarity.1.4.1 Dipole Moment and Dispersive Forces.1.4.2 Dielectric Constant.1.4.3 Electron Pair Donor and Acceptor Numbers.1.4.4 Empirical Polarity Scales.1.4.5 ENT and ET(30) Parameters.1.4.6 Kamlet-Taft Parameters.1.4.7 Hydrogen Bond Donor (HBD) and Hydrogen Bond Acceptor (HBA) Solvents.1.5 The Effect of Solvent Polarity on Chemical Systems.1.5.1 The Effect of Solvent Polarity on Chemical Reactions.1.5.2 The Effect of Solvent Polarity on Equilibria.1.6 W hat is Required from Alternative Solvent Strategies?References.2 Multiphasic Solvent Systems.2.1 An Introduction to Multiphasic Chemistry.2.1.1 The Traditional Biphasic Approach.2.1.2 Temperature Dependent Solvent Systems.2.1.3 Single- to Two-Phase Systems.2.1.4 Multiphasic Systems.2.2 Solvent Combinations.2.2.1 Water.2.2.2 Fluorous Solvents.2.2.3 Ionic Liquids.2.2.4 Supercritical Fluids and Other Solvent Combinations.2.3 Benefits and Problems Associated with Multiphasic Systems.2.3.1 Partially Miscible Liquids.2.4 Kinetics of Homogeneous Reactions.2.4.1 Rate is Independent of Stoichiometry.2.4.2 Rate is Determined by the Probability of Reactants Meeting.2.4.3 Rate is Measured by the Concentration of the Reagents.2.4.4 Catalysed Systems.2.5 Kinetics of Biphasic Reactions.2.5.1 The Concentration of Reactants in Each Phase is Affected by Diffusion.2.5.2 The Concentration of the Reactants and Products in the Reacting Phase is Determined by Their Partition Coefficients.2.5.3 The Partition Coefficients of the Reactants and Products May Alter the Position of the Equilibrium.2.5.4 Effect of Diffusion on Rate.2.5.5 Determining the Rate of a Reaction in a Biphasic System.2.6 Conclusions.References.3 Reactions in Fluorous Media.3.1 Introduction.3.2 Properties of Perfluorinated Solvents.3.3 Designing Molecules for Fluorous Compatibility.3.4 Probing the Effect of Perfluoroalkylation on Ligand Properties.3.5 Partition Coefficients.3.6 Liquid-Liquid Extractions.3.7 Solid Separations.3.8 Conclusions.References.4 Ionic Liquids.4.1 Introduction.4.1.1 The Cations and Anions.4.1.2 Synthesis of Ionic Liquids.4.2 Physical Properties of Ionic Liquids.4.3 Benefits and Problems Associated with Using Ionic Liquids in Synthesis.4.4 Catalyst Design.4.5 Conclusions.References.5 Reactions in Water.5.1 The Structure and Properties of Water.5.1.1 The Structure of Water.5.1.2 Near-Critical Water.5.1.3 The Hydrophobic Effect.5.1.4 The Salt Effect.5.2 The Benefits and Problems Associated with Using Water in Chemical Synthesis.5.3 Organometallic Reactions in Water.5.4 Aqueous Biphasic Catalysis.5.4.1 Ligands for Aqueous-Organic Biphasic Catalysis.5.5 Phase Transfer Catalysis.5.5.1 The Transfer of Nucleophiles into Organic Solvents.5.5.2 Mechanisms of Nucleophilic Substitutions Under Phase Transfer Conditions.5.5.3 The Rates of Phase Transfer Reactions.5.5.4 Using Inorganic Reagents in Organic Reactions.5.6 Organometallic Catalysis under Phase Transfer Conditions.5.7 Triphase Catalysis.5.7.1 Mixing Efficiency in Solid-Liquid Reactions.5.8 Conclusions.References.6 Supercritical Fluids.6.1 Introduction.6.2 Physical Properties.6.3 Local Density Augmentation.6.4 Supercritical Fluids as Replacement Solvents.6.5 Reactor Design.6.6 Spectroscopic Analysis of Supercritical Media.6.6.1 Vibrational Spectroscopy.6.6.2 NMR Spectroscopy.6.7 Reactions in Supercritical Media.6.8 Conclusions.References.7 Diels-Alder Reactions in Alternative Media.7.1 Diels-Alder Reactions in Water.7.2 Diels-Alder Reactions in Perfluorinated Solvents.7.3 Diels-Alder Reactions in Ionic Liquids.7.4 Diels-Alder Reactions in Supercritical Carbon Dioxide.7.5 Conclusions.References.8 Hydrogenation and Hydroformylation Reactions in Alternative Solvents.8.1 Introduction.8.2 Hydrogenation of Simple Alkenes and Arenes.8.2.1 Hydrogenation in Water.8.2.2 Hydrogenation in Ionic Liquids.8.2.3 Hydrogenation in Fluorous Solvents.8.2.4 Hydrogenation in Supercritical Fluids.8.3 Hydroformylation Reactions in Alternative Media.8.3.1 Hydroformylation in Water.8.3.2 Hydroformylation in Ionic Liquids.8.3.3 Hydroformylation in Fluorous Solvents.8.3.4 Hydroformylation in Supercritical Fluids.8.4 Conclusions.References.9 FromAlkanestoCO2: Oxidation in Alternative Reaction Media.9.1 Oxidation of Alkanes.9.2 Oxidation of Alkenes.9.3 Oxidation of Alcohols.9.4 Oxidation of Aldehydes and Ketones.9.5 Destructive Oxidation.9.6 Conclusions.References.10 Carbon-Carbon Bond Formation, Metathesis and Polymerization.10.1 Carbon-Carbon Coupling Reactions.10.1.1 Heck Coupling Reactions.10.1.2 Suzuki Coupling Reactions.10.1.3 Reactions Involving the Formation of C=C Double Bonds.10.2 Metathesis Reactions.10.2.1 Ring Opening Metathesis Polymerization.10.2.2 Ring Closing Metathesis.10.3 Polymerization Reactions in Alternative Reaction Media.10.3.1 Polymerization Reactions in Water.10.3.2 Polymerization Reactions in Supercritical Carbon Dioxide.10.3.3 Polymerization in Fluorous Solvents.10.4 Conclusions.References.11 Alternative Reaction Media in Industrial Processes.11.1 Obstacles and Opportunities for Alternative Media.11.2 Reactor Considerations for Alternative Media.11.2.1 Batch Reactors.11.2.2 Flow Reactors.11.2.3 New Technology Suitable for Multiphasic Reactions.11.3 Industrial Applications of Alternative Solvent Systems.11.3.1 The Development of the First Aqueous-Organic Biphasic Hydroformylation Plant.11.3.2 Other Examples of Processes Using Water as a Solvent.11.3.3 Scale-Up of PTC Systems.11.3.4 Thomas Swan Supercritical Fluid Plant.11.3.5 Other Applications of Supercritical Carbon Dioxide.11.4 Outlook for Fluorous Solvents and Ionic Liquids.11.5 Conclusions.References.Index.

Electrochemical intercalation of lithium ion within graphite from propylene carbonate solutions

Abstract: Electrochemical lithium intercalation within graphite was investigated in propylene carbonate (PC) containing different concentrations, 0.82 and 2.72 mol dm - 3 , of bis(perfluoroethylsulfonyl)imide, LiN(SO 2 C 2 F 5 ) 2 . Lithium ion was reversibly intercalated into and deintercalated from graphite in the latter concentrated solution in spite of the use of pure PC as a solvent, whereas ceaseless solvent decomposition and intensive exfoliation of graphene layers occurred in the former solution. X-ray diffraction analysis revealed that a stage I graphite intercalation compound was formed alter being fully charged in the 2.72 mol dm - 3 solution. The results of Raman analysis indicated that no free PC molecules are present in the concentrated solution, which suggested that the ion/solvent interactions would be an important factor that determines the ability of stable surface film formation in PC-based solutions.

Probing solute and solvent interactions within binary ionic liquid mixtures

Abstract: In this communication, we explore solute–solvent and ion–ion interactions within binary ionic liquid mixtures. From the perspective of several solvatochromic reporter probes capable of a range of interactions, we have investigated the influence of mixture composition on the polarity, dielectric, hydrogen bonding interactions, and microfluidity within mixtures afforded by the ionic liquids 1-butyl-3-methylimidazolium bis(triflyl)imide, 1-ethyl-3-methylimidazolium bis(triflyl)imide, and 1-butyl-3-methylimidazolium hexafluorophosphate. Our results underscore the prevalence of hydrogen bond donor and competitive anion coordination effects, suggesting the possible use of such mixtures in the design and optimization of advanced media for separations or chemical processing.

Effect of Solvents and Concentration on the Formation of a Self-Assembled Monolayer of Octadecylsiloxane on Silicon (001)

Abstract: We have explored the effects of solvent, adsorber concentration, and environment on the formation of high-coverage monolayers of alkylsiloxanes on silicon oxide surfaces from alkylsiloxane solutions. Specifically, we have varied the solvent polarity and the concentration of octadecyltrichlorosilane (OTS) used for the deposition process. We found that for a wide range of concentrations (25 μM to 2.5 mM) and normal laboratory air humidity (RH 45−85%) OTS dissolved in heptane causes the formation of a full-coverage self-assembled monolayer on hydrophilic silicon oxide. The resulting self-assembled layers were studied by atomic force microscopy, ellipsometry, and X-ray reflectometry. Deposition of OTS from dodecane solutions resulted in multilayered films. In contrast, the use of heptane as solvent (in which the solubility of water is at intermediate level between toluene and dodecane) caused the formation of high-quality monolayers. We found consistent and reproducible results for the effect of solvents (dod...