Swelling of compressed cellulose fiber webs in organic liquids

Maximum liquid-holding capacities of various compressed fibers in water and in a series of various organic liquids have been investigated. The maximum liquid-holding capacity versus bulk density relationships gave polynomial curves, generally with a peak. Good relative correlations for cellulose, compressed fiber pellets and wood were found for the series of liquids tested. In general, liquids that swelled wood to a low to medium range (up to 6%) did not swell appreciably -cellulose and sulfite pulp, while good to excellent wood-swelling agents swelled all the fibers very significantly. It was also found that the hydrogen-bonding parameter of the swelling liquid was the most important factor. The swelling rate of various compressed fiber systems in organic liquids was dramatically increased by raising the temperature. Activation energies and molar volume of the swelling liquid were linearly correlated.     

Synthesis and Characterization of Task‐Specific Ionic Liquids Possessing Two Brönsted Acid Sites

Abstract

Task‐specific ionic liquids possessing two Brönsted acid sites with –COOH, HSO^? ₄, or H₂PO^? ₄ groups have been designed, synthesized, and characterized. Under mild conditions and without any additional organic solvent, the esterification of isopropanol by chloroacetic acid could be carried out in these new task‐specific ionic liquids. In comparison with most of acidic ionic liquids in current use, these ionic liquids are halogen free and more environmentally benign as media and catalysts.     

Assay of Sulfur in Organic Liquids Using a Mercury Displacement Method

Abstract

A method for the assay of sulfur in organic liquids is presented. The method utilizes an oxidative combustion process coupled with a piezoelectric crystal detector. The sulfur dioxide evolved upon combustion of the organic liquid is bubbled through a mercurous nitrate solution. The mercury vapor produced is detected by a piezoelectric crystal due to the formation of a mercury amalgam.     

Review article: some transport phenomena in classical liquids and neutron scattering

Abstract

The sound velocity in toluene has been measured up to 2634 bar and at temperatures from 173 to 320 K using the pulse-echo overlap method. The sound velocity in n-heptane has been measured up to 2634 bar and at temperatures from 185 to 310 K by the phase comparison pulse-echo method. The density, the isothermal compressibility, the isobaric thermal expansion and the specific heat at constant pressure of both liquids have been evaluated from the measured sound velocity, following the method of Davis and Gordon. From a comparison of the calculated densities with those obtained previously from direct measurements, it is concluded that the method is very suitable for precise determination of liquid densities under elevated pressures.     

Experimental Equations of State for Some Organic Liquids Between 273 and 333 K and Up to 280 MPa

Abstract

Five non-linear and three polynomial isothermal equations of state for liquids have been tested for their performance in describing the data of the density and the isothermal compressibility of benzene and cyclohexane from 288 to 323 K up to the melting pressures, and of methanol and ethanol between 273 and 333 K up to 280 MPa. It is found that the best representation is given by an expansion in temperature and density and the second best by the Usual Tait equation. The coefficients of these two equations for the four organic liquids are obtained by fitting the experimental data by a least squares analysis.     

Histidine-based salt as an ionic tag for proline: application in enantioselective cross aldol reaction in ionic liquids

Abstract

A new ionic-liquid supported aminocatalyst was synthesized by the peptide coupling of proline on a ring-dialkylated histidine salt serving as ionic support. The catalytic activity and enantioselectivity of the obtained dipeptide catalyst were evaluated in the enantioselective cross aldol reaction of substituted benzaldehyde derivatives with acetone, in organic solvent and in ionic liquids, and both were found to be significantly higher in ionic liquids than in organic solvents. The [bmim][OTf] – catalyst system could be recycled for up to five cycles without any loss in activity.     

Thermodynamic and acoustic properties of binary mixtures of PEGDME 250 with 1-propanol and 1-butanol at 293, 303 and 313°K

ABSTRACT

The work presented in this paper deals with the study of thermodynamic properties of new working fluids for absorption machines, mainly for characterisation of absorbent–refrigerant pairs that could improve the cycle performance. The study of atomic motion in liquids plays an important role in understanding the solid-like behaviour of liquids. The accurate measurement of the energy changes due to scattering can be used to study the dynamical behaviour of liquids. Measurements of the ultrasonic velocity (u), density (ρ) and viscosity (η) for binary mixtures of polyethylene glycol 250 dimethyl ether with 1-propanol and 1-butanol have been made at three temperatures (T = 293, 303 and 313 K) over the entire composition range in order to investigate the nature of intermolecular interactions between the components of these liquid mixtures. Non-linear variation of derived quantities with the mole fraction supports the molecular interaction occurring between component molecules.     

Dependence of Surface Tension of Near-boiling Non-associated Liquids on Their Molar Volume and Some Critical Constants

Abstract

The equation proposed for near-boiling non-associated liquids describes a new functional dependence of their surface tension on such physico-chemical characteristics as: critical volume, critical temperature and molar volume at the temperatures which are near their normal boiling points. It is shown that, in the case of some low-boiling liquids, possessing small molecules, this equation can be used for the adequate calculation of surface tension at different temperatures in the liquid phase.     

Effect of Core-Ion Potentials on Thermodynamic Properties of Liquid Alkali Metals and Alloys

Abstract

A pseudopotential perturbation scheme based on Gibbs-Bogoliubov variational technique is considered to investigate the structure and volume dependent contributions to the internal energies of liquid alkali metals. This has paved the way to analyse the effect of core-ion potentials on Helmholtz free energy, enthalpy, pairwise interactions and on entropy of liquids Na, K, Rb and Cs. Excess entropy of mixing for Na-K. Na-Cs and K-Rb are also calculated and are found very sensitive to the core-ion potentials.     

Recent advances in ionic liquids: green unconventional solvents of this century: part I

Abstract

The present overview describes ionic liquids as alternate, attractive solvents of today and tomorrow in organic synthesis. Since this subject is too wide and developments have been too fast, only a recent account is presented on indispensable carbon-carbon bond forming named reactions such as Knoevenagel, Michael Aldol, Biginelli Reaction, and so on, which has never been done before exclusively.     

Synthesis of a series of novel dihydro-[1,2,4]triazolo [1,5-a]pyrimidine scaffolds: Dual solvent-catalyst activity of a low viscous and acid-functionalized ionic liquid

Abstract

The viscosity of neat ionic liquids is very important for their application in organic synthesis as a solvent because most of the neat ionic liquids are very viscous, which would result in the less efficient mass transfer of reactants. In the present study, a series of novel dihydro-[1,2,4]triazolo[1,5-a]pyrimidines were prepared using a low viscous and acid-functionalized ionic liquid. Our results showed that new ionic liquid can act as a green solvent and acid catalyst due to low viscosity and acid functionality. The products were simply extracted and the ionic liquid was retrieved several times without reducing its catalytic efficiency. The current application of TMDPS in the one-pot multicomponent reactions as dual solvent-catalyst highlights the importance of low viscous acid-functionalized ionic liquids in organic synthesis, and we hope that further research will be conducted in the future to finding other applications of TMDPS with promising results.     

Dispersion Property of CO2 in Oil. Part 3: Aggregation of CO2 Molecule in Organic Liquid at Near Critical and Supercritical Condition of CO2

To study the dispersion property of CO₂ in organic liquids, the solubility of CO₂, the volume of CO₂ + organic liquids under different pressure at 318.15 K were measured and the radial distribution function of CO₂ molecule aggregate in the organic liquids was calculated by molecule dynamic simulation. The results show that the aggregate of CO₂ molecules in the organic liquids is formed obviously; the aggregation and disperse property of CO₂ molecule in the organic liquids is affected by the structure and polarity of the organic molecule at near critical and supercritical condition of CO₂ dominantly.     

Metal Organic Precursors for Yttria

Abstract

Several carboxylic acid derivatives of yttrium that have potential as metal organic deposition (MOD) precursors for yttria were prepared and characterized. These included a traditional MOD precursor bearing 2-ethylhexanoate ligands and a new class of precursors bearing poly-ether carboxylic acid ligands. Notably, the latter complexes are viscous liquids.     

Recent developments of task-specific ionic liquids in organic synthesis

Abstract

Task-specific ionic liquids (TSILs) have received increased attention over the past few years as it is possible to form any specific ionic liquid (IL) composition depending upon user's need of the desired physical, chemical, and biological properties. These fascinating materials have shown promising results in various areas such as organic synthesis, catalysis, and specially recent emerging trend of use as functionalized ILs for chiral and nanoparticle synthesis. Present review gives an update of recent developments in the field of TSILs with emphasis on their applications in organic synthesis.     

Study of Analytical Methods for Iron Determination in Complex Organic Liquids by Atomic Absorption Spectrometry

Abstract

In the determination of iron in complex organic liquids by atomic absorption spectrometry (A. A. S.), methods of sample preparation, such as dilution with an organic solvent and sample pretreatment to destroy organic material, are investigated. Moreover, methods of analysis using calibration curve and standard additions are presented. The possible cause of error associated with iron determination in organic samples by flame (F-A. A. S.) and graphite furnace (GF-A. A. S.) atomic absorption spectrometry are discussed.

From all of these studies, the use of graphite furnace atomic absorption spectrometry after sample dilution with methyl isobutyl ketone, and the use of the method of standard additions are advised for iron determination.     

Dielectric Studies of Binary Mixtures of some Amines—Aniline and Pyridine—in Nonpolar Solvents—Solute–Solvent Interactions

Abstract

Dielectric constant of binary mixtures of aniline and also pyridine in nonpolar liquids namely benzene, carbon tetrachloride, p-xylene and n-heptane have been measured at 455 kHz for four different temperatures. Eyring's interaction parameter G? based on the significant structure model is calculated in the mixtures using the experimentally determined value of dielectric constant.

The nature of the solvent is found to influence this parameter G? reflecting the non-specific solute-solvent interaction. The calculated value of G? is used for interpreting dipole interaction of solute molecules in the solvent environment.     

Polyvinylacetate Gel Permeation Chromatography of H-Coal Liquids and Model Compounds. Comparison with Rigid Gel,Reversed Phase and Normal Phase Chromatography

Abstract

This paper reports the application of polyvinylacetate gel (Fractogel) for size fractionation of the H-Coal liquids and model aromatic hydrocarbons. The four H-Coal liquids were each divided into three classes according to solubility in hexane, benzene, and pyridine. A model mixture of eight compounds when applied to the Fractogel column yielded four fractions; a similar performance was given by a prepacked, Toyo Soda microparticulate column containing styrene-divinylbenzene copolymer. Regarding the twelve H-Coal solvent fractions, the chromatograms obtained from the Fractogel column were analogous to those from the Toyo Soda column. By making further use of model compounds, the Fractogel results are compared with those obtained from reversed phase chromatography on a Partisil ODS column and those from normal phase chromatography on a LiChrosorb silica column. These comparisons reveal the usefulness in separating certain aromatic hydrocarbons by the Fractogel column. Furthermore, judging from the chromatograms of a hexane-soluble H-Coal fraction obtained by the reversed phase and normal phase methods, the ODS column will complement the Fractogel column in fractionating the H-Coal liquids.     

Electronic and Ionic Ordering in Condensed Matter Plasmas. (Phase Transitions Induced by Coulomb Interactions)

Abstract

Recent progress in treating phase transitions induced by Coulomb interactions is reviewed. This is done by appealing to simple models, and in particular to the one-component plasma, with its quantum-mechanical counterpart jellium. The relevance of the phase transition, to a body-centred-cubic crystal in the classical one-component plasma, to the freezing of liquid metals Na and K is stressed. By generalizing these arguments to a two-component system, regularities in the freezing of the molten alkali halides are understandable. Sublattice disorder in superionics, driven by Coulomb forces, is then discussed. Finally, the ordering of electrons in jellium, in the limit of complete degeneracy, is considered; evidence being presented for the existence of electron liquids in molten Na and K.     

Estimates of Internal Pressure and Molar Refraction of Imidazolium Based Ionic Liquids as a Function of Temperature

Estimates of the internal pressure (∂ U/∂ V) _T of the ionic liquids (ILs) 1-butyl-3-methylimidazolium tetrafluoroborate [BMIM][BF₄], 1-butyl-3-methylimidazolium hexafluorophosphate [BMIM][PF₆], and 1-methyl-3-octylimidazolium tetrafluoroborate [OMIM][BF₄] were made from experimentally determined densities and speeds of sound in the temperature range 283.15 to 343.15 K. Values (∂ U/∂ V) _T for all the ILs studied are higher than those of water and molecular organic liquids. We also measured the refractive indices n _D in the temperature range 288.15 to 343.15 K and estimated the molar refraction R _M. Refractive indices of ILs were also higher than those of normal organic liquids but were comparable to those of long hydrocarbon chain organic solvents.     

Effect of solvents on the cryogenic dynamic mechanical properties of polystyrene

Young's modulus and mechanical damping of 15 organic liquids in polystyrene have been measured from 4°K to 250°K. The concentration was generally in the range from 10 to 15%, but the polystyrene–toluene system was investigated over the range from 0 to 16%. Some liquids cause the 40°K damping peak of polystyrene to disappear, other liquids do not. Seven of the liquids which cause the disappearance of the 40°K peak give rise to new large damping peaks at the temperature expected for the secondary glass transition temperatures of the liquids, that is, at 0.77 T_g of the liquids. Some of the liquids produced large unexplained damping peaks at temperatures above the expected glass transition temperatures T_g of the liquids. It is suggested that the γ peak in polystyrene is caused by styrene monomer.