scispace - formally typeset
Search or ask a question

Showing papers on "Solvent published in 1969"



Journal ArticleDOI
TL;DR: In this article, the authors extended the theory of gas-chromatographic elution of a highly dilute solute to the second order in gas-phase imperfection terms, yielding a precise expression for the ideal retention volume in terms of the thermodynamic parameters of the system.
Abstract: This paper extends the theory of gas-chromatographic elution of a highly dilute solute to the second order in gas-phase imperfection terms, yielding a precise expression for the ideal retention volume in terms of the thermodynamic parameters of the system. The effect of carrier gas dissolution in the solvent is included explicitly; the cross-term second virial coefficient B12 for the system solute + carrier gas cannot be evaluated unambiguously for an appreciably soluble carrier gas. The use in such cases of polar solvents in which non-polar carrier gases are effectively insoluble is discussed with reference to surface adsorption and chromatographic non-ideality, which are important in polar solvents. Extrapolation of observed retention volume to zero flowrate for each of a series of columns covering a range of solvent loadings should give, corresponding to the limit of infinite loading, unambiguous values of bulk-phase solute-in-solvent activity coefficient and of B12. The theory has been applied to measurements on the systems benzene + nitrogen + glycerol, and benzene + carbon dioxide + glycerol, using four columns loaded at 15.7, 25.3, 33.6 and 23.3 % by weight glycerol on Celite, and the system benzene + hydrogen + glycerol using a column loaded at 44.0 %. The flowrate-dependence of the net retention volume is approximately linear on all columns, the gradient correlating well with empirical plate height and with solvent loading, in accordance with theory and with the known facts about the distribution of a polar solvent on Celite. The zero-flowrate B12 values are effectively the same with all columns. These values of B12 at 50°C are, for benzene + nitrogen, –98 ± 9 cm3 mole–1, and for benzene + carbon dioxide, –250 ± 15 cm3 mole–1, both being in fair agreement with theoretical predictions for systems of non-spherical molecules of different sizes. The activity coefficient for benzene at infinite dilution in glycerol at 50°C is logγ∞13= 2.084 ± 0.005.

170 citations


Journal ArticleDOI
TL;DR: In this paper, the excess Gibbs energy of mixing at 45 °C of 2-methyl-1-propanol, 2-butanol, and 2methyl-2-propane in benzene and n-hexane solutions was investigated.

168 citations



Journal ArticleDOI
TL;DR: The ratios of selectivities among the various cations were discovered to be characteristic of a given antibiotic and to be completely independent of the solvent used, and the equilibrium constant for the extraction of each cation by a given macrotetralide actin antibiotic was found to be measurable with sufficient precision.
Abstract: In order to clarify the mechanism by which neutral molecules such as the macrotetralide actin antibiotics make phospholipid bilayer membranes selectively permeable to cations, we have studied, both theoretically and experimentally, the extraction by these antibiotics of cations from aqueous solutions into organic solvents. The experiments involve merely shaking an organic solvent phase containing the antibiotic with aqueous solutions containing various cationic salts of a lipid-soluble colored anion. The intensity of color of the organic phase is then measured spectrophotometrically to indicate how much salt has been extracted. From such measurements of the equilibrium extraction of picrate and dinitrophenolate salts of Li, Na, K, Rb, Cs, and NH4 into n-hexane, dichloromethane, and hexane-dichloromethane mixtures, we have verified that the chemical reactions are as simple as previously postulated, at least for nonactin, monactin, dinactin, and trinactin. The equilibrium constant for the extraction of each cation by a given macrotetralide actin antibiotic was also found to be measurable with sufficient precision for meaningful differences among the members of this series of antibiotics to be detected. It is noteworthy that the ratios of selectivities among the various cations were discovered to be characteristic of a given antibiotic and to be completely independent of the solvent used. This finding and others reported here indicate that the size and shape of the complex formed between the macrotetralide and a given cation is the same, regardless of the species of cation bound. For such “isosteric” complexes, notable simplifications of the theory become possible which enable us to predict not only the electrical properties of a membrane made of the same solvent and having the thinness of the phospholipid bilayer but also, and more importantly, the electrical properties of the phospholipid bilayer membrane itself. These predictions will be compared with experimental data for phospholipid bilayer membranes in the accompanying paper.

120 citations



Journal ArticleDOI
TL;DR: In this article, a modified Wilke-Chang type equation was used to predict the diffusion data over the entire solvent mixture concentration range using only diffusion data of the solute in each of the pure solvents and viscosity data of mixtures.

108 citations


Patent
04 Jun 1969
TL;DR: In this paper, the authors propose a method for developing a grid consisting of a HYDROPHOBIC, SHELL-FORMING POLYMER in a low boiling point and a high boiling point.
Abstract: A METHOD FOR PRODUCING MICROCAPSULES INCLUDING DISSOLVING A HYDROPHOBIC, SHELL FORMING POLYMER IN A LOW BOILING POINT SOLVENT, MIXING THE RESULTING SOLUTION IN A WATER-INSOLUBLE HIGH BOILING POINT SOLVENT WHICH IS A POOR SOLVENT FOR THE POLYMER, EMULSIFYING THE MIXTURE IN AN AQUEOUS MEDIUM AT A TEMPERATURE BELOW THE BOILING POINT OF THE LOW BOILING SOLVENT, AND HEATING THE EMULSION TO ABOVE THE BOILING POINT OF THE LOW BOILING SOLVENT, BUT BELOW THE BOILING POINT OF THE HIGH BOILING SOLVENT.

101 citations


Patent
11 Jun 1969
TL;DR: An improved solvent and process for treating and separating acid gas, particularly hydrogen sulfide from gas mixtures containing the same, is described in this paper, which involves the use of a solvent comprising a mixture of dimethyl ethers of polyethylene glycols to absorb the hydrogen sulphide and part of the carbon dioxide under superatmospheric pressure.
Abstract: An improved solvent and process for treating and separating acid gas, particularly hydrogen sulfide from gas mixtures containing the same, such as natural gas mixtures containing hydrogen sulfide, carbon dioxide and methane. The process involves the use of a solvent comprising a mixture of dimethyl ethers of polyethylene glycols to absorb the hydrogen sulfide and part of the carbon dioxide under superatmospheric pressure. The solvent containing dissolved hydrogen sulfide and carbon dioxide is flashed at reduced pressure to remove most of the carbon dioxide and produce a ''''semilean'''' solvent. Part of the semilean solvent is recycled to an intermediate part of the absorber; the remaining semilean solvent containing hydrogen sulfide is subjected to an oxygen containing gas under conditions that result in complete removal of the hydrogen sulfide to produce a ''''lean'''' solvent. The lean solvent is recycled to the top of the absorber. By the use of two solvent feeds to the absorber, the economy of the process is improved.

92 citations


Journal ArticleDOI
J.B Peri1
TL;DR: In this article, the state of solution of Aerosol OT (di-2-ethylhexyl sodium sulfosuccinate) was investigated in various nonaqueous solvents with the use of ultracentrifugation, light scattering, and viscometric techniques.

81 citations


Journal ArticleDOI
TL;DR: A quantitative analysis indicates that the spectral changes are due to replacement by water of one molecule of co-ordinated dimethyl sulphoxide per ferrihaem aggregate, and do not involve a two-molecule replacement as has been suggested for the alkaline pyridine-water system.
Abstract: 1. Conductivity and u.v. and visible spectroscopic techniques were used to investigate the solution structure of the prosthetic group of the ferric haemoproteins (ferrihaem) in dimethyl sulphoxide, NN-dimethylacetamide, NN-dimethylformamide and sulpholane, and certain of their aqueous mixtures. 2. In neutral or acid dimethyl sulphoxide, chlorohaemin is monomeric and completely dissociated into Cl(-)ion and a ferrihaem species with dimethyl sulphoxide molecules in the fifth and sixth co-ordination positions on iron. 3. In neutral NN-dimethylacetamide and NN-dimethylformamide chlorohaemin is monomeric but is largely undissociated, giving different spectra from that of chlorohaemin in dimethyl sulphoxide. On acidification, dissociation occurs and the dimethyl sulphoxide type of spectrum results. 4. Studies in a fourth solvent, sulpholane, indicate that solvent co-ordinating power (ligand strength) rather than bulk dielectric constant is responsible for dissociation of chlorohaemin. 5. In neutral dimethyl sulphoxide-water mixtures chlorohaemin remains monomeric and completely dissociated, and spectra are independent of mixture composition, except at high water concentrations, when precipitation occurs. In alkaline dimethyl sulphoxide-water mixtures, where the complete solvent mixture range is accessible, ferrihaem is polymeric (probably dimeric) and spectra are dependent on solvent composition. A quantitative analysis indicates that the spectral changes are due to replacement by water of one molecule of co-ordinated dimethyl sulphoxide per ferrihaem aggregate, and do not involve a two-molecule replacement as has been suggested for the alkaline pyridine-water system.

Journal ArticleDOI
01 Jan 1969
TL;DR: In ternary systems of ionic association colloids, two regions of homogeneous isotropic solution occur, namely, a region of ordinary aqueous solution and a region L 2 in which the added amphiphilic substance is the solvent as mentioned in this paper.
Abstract: In ternary systems of ionic association colloids—for instance, an alkali soap, water, and a liquid fatty acid or alcohol—two regions of homogeneous isotropic solution occur, namely, a region L 1 of ordinary aqueous solution and a region L 2 in which the added amphiphilic substance is the solvent. Both have micellar structure: the micelles in L 1 are of the usual type with a hydrocarbon core; those in L 2 are of a “reversed” type with a water core, surrounded by amphiphile molecules, oriented with the hydrophilic groups facing the water and the hydrocarbon chains outwards. The micelles are formed in different ways in L 2 solutions of the fatty acid and alcohol systems. In the former a molecular compound of soap and fatty acid forms even in the water-free state; the acid soap binds water and in hydrated form gives rise to micelles of the “reversed” type, dissolved in fatty acid. In the water-free alcohol-soap system no corresponding molecular compound is formed; the L 2 solutions require a certain minimum amount of water for their existence and aggregates between alcohol and soap form only through the agency of water. They give rise to micelles of the “reversed” type, dissolved in alcohol.

Journal ArticleDOI
TL;DR: In this paper, the S3→S1 internal conversion efficiency of benzene is found to depend critically on the effectiveness of environmental perturbation in mixing the S 3 and S 1 states.
Abstract: The S3 → S1 internal conversion efficiency of benzene is found to depend critically on the effectiveness of environmental perturbation in mixing the S3 and S1 states. Evidence for this derives from the experimental correlation of the conversion efficiency with the intensities of the 0–0 absorptive and emissive transitions in solutions with the solvents benzene, methanol, isopropyl alcohol, tetrahydrofuran, ethyl ether, acetonitrile, hexane, cyclohexane, methylcyclohexane, decalin, isooctane, and perfluorinated hexane. Additionally, the importance of S3 − S1 mixing is shown to explain the marked increase in the efficiency of internal conversion observed upon methyl substitution of benzene.


Journal ArticleDOI
TL;DR: In this paper, the distributions of the zinc chelate with thenoyltrifluoroacetone (TTA) between an aqueous solution and twelve inert organic solvents were investigated; it was found that there is a correlation which can be expressed as logPM=nlogPHA+const.
Abstract: The distributions of the zinc chelate with thenoyltrifluoroacetone (TTA) between an aqueous solution and twelve inert organic solvents were investigated. After it had been confirmed that the distributed species were ZnA2, the distribution coefficients of the chelate (PM) and those of TTA (PHA) were compared; it was found that there is a correlation which can be expressed as logPM=nlogPHA+const. When TTA and TBP are in the extraction system, the adduct formation constants of chelate were obtained. The activities of all the species which take part in the adduct formation were evaluated on the basis of the regular solution theory. It was found that the adduct formation constant in terms of activity (Ks°) is constant in all the organic solvents; namely, logKs° was found to be 4.05. Finally, the role of the solvent in the synergistic extraction system is explained systematically by a combination of the regularity in the distribution and that in the adduct formation.


Patent
Samuel S. Mims1
19 Aug 1969
TL;DR: In this article, a process comprising adding an alcohol to the aqueous solution to esterify the acids present, while preferably simultaneously contacting the alcoholic mixture with a water-immiscible solvent and separating layers into an organic phase, is described.
Abstract: Organic acids contained in aqueous solution are separated and/or recovered by a process comprising adding an alcohol to the aqueous solution to esterify the acids present, while preferably simultaneously contacting the alcoholic mixture with a water-immiscible solvent and separating layers into an aqueous phase and an organic phase, whereby extraction with the water-immiscible solvent shifts the equilibrium toward the formation of more esters. The esters of the acids may than be recovered as by distillation.

Journal ArticleDOI
01 Feb 1969-Talanta
TL;DR: Solvent-uptake properties for several synthetic resins and common adsorbents were determined by the centrifugation method and the swelling properties of these non-polar resins are compared with each other and with the polar cation resins.

Journal ArticleDOI
TL;DR: In this article, the solubility and polarographic behavior of dissolved oxygen have been investigated in air-saturated DMSO-water mixtures at 25°C and 45°C.
Abstract: The solubility and polarographic behavior of dissolved oxygen have been investigated in air-saturated DMSO-water mixtures at 25°C and 45°C. The first oxygen wave, which corresponds to one-electron reduction to superoxide ions in water-poor DMSO solutions of 0.1 M Et4NClO4, changes to a two-electron process in the range of water content between 10 and 30% because of the protonation reaction due to water. The rate of protonation is potential-dependent. The rate also depends on the species and the concentrations of the supporting electrolytes. The temperature effect is small. Using the solubility and polarographic data obtained, the polarographic diffusion coefficients of oxygen in the mixed solvent have been calculated.


Patent
12 Nov 1969
TL;DR: In this paper, the authors describe a solvable Ion exchange reaction in which HYDROGEN IONS in the AQUEOUS LIQUOR are exchanged for METAL CATIONS in an Ion extract.
Abstract: SOLVENT ION EXCHANGE REACTION IN WHICH THE PH OF THE METAL-BEARING LIQUOR IS REGULATED BY AN ION EXCHANGE REACTION WHERE HYDROGEN IONS IN THE AQUEOUS LIQUOR ARE EXCHANGED FOR METAL CATIONS IN AN ION EXTRACT. PROCESS ENABLES LOADING AN ION EXTRACTANT WITH METALS IN THE METAL-BEARING LIQUOR WITHOUT INTERSTAGE PH ADJUSTMENT. THE LOADED ION EXTRACTANT IS TREATED WITH A LIGAND TO STRIP THE EXTRACT AND RENDER IT CAPABLE OF REUSE.

Journal ArticleDOI
TL;DR: A survey on gradient elution TLC is given in this paper, where four processes are known to effect gradients in the mobile phase (elution gradients): frontal analysis of a multicomponent solvent (polyzonal TLC), mechanical alteration of solvent composition in the solvent reservoir (solvent gradient), preimpregnation of the adsorbent by vapors of polar or nonpolar substances (vapor, impregnation gradient), and partial removal of mobile phase during chromatography (flux gradient).
Abstract: A survey on gradient elution TLC is given. At present four processes are known to effect gradients in the mobile phase (“elution gradients”): frontal analysis of a multicomponent solvent (polyzonal TLC), mechanical alteration of solvent composition in the solvent reservoir (solvent gradient), preimpregnation of the adsorbent by vapors of polar or nonpolar substances (vapor, impregnation gradient), and partial removal of mobile phase during chromatography (flux gradient).

Patent
Michael G Romanelli1
19 Mar 1969
TL;DR: In this article, the unsaturated alcohols and ethers are prepared through the reaction of C4 to C6 aliphatic conjugated diolefins with water, a lower alkanol or mixtures thereof in the presence of a zero valent palladium based catalyst system.
Abstract: Unsaturated alcohols and ethers are prepared through the reaction of C4 to C6 aliphatic conjugated diolefins with water, a lower alkanol or mixtures thereof in the presence of a zero valent palladium based catalyst system. The preferred catalyst is tetrakis(triphenyl-phosphine)palladium alone or in combination with a basic material such as a quaternary ammonium hydroxide. Where one of the coreactants is water, the reaction is conducted in the presence of a solvent. The unsaturated alcohol and ether products can be catalytically hydrogenated to plasticizer alcohols and ether solvent media.

Patent
22 Dec 1969
TL;DR: In this article, a water-soluble deterministic deterministic solver is used to deter the use of deterministic water solvers in the water-maintaining membrane.
Abstract: MEMBRANES SPECIALLY ADAPTED TO PREFERENTIALLY PERMIT THE PASSAGE OF RELATIVELY PURE WATER THROUGH THEM, WHILE RESISTING THE PASSAGE OF DISSOLVED SALTS MUST CONVENTIONALLY BE KEPT WATER-WET IN ORDER TO RETIAN THIS ABILITY TO EXCLUDE SALTS. DRY, REWETTABLE, STABILIZED MEMBRANES IN WHICH THIS DESIRABLE PROPERTY IS PRESERVED, CAN BE MADE BY TREATING THE WET MEMBRANE FIRST WITH A WATER-MISCIBLE SOLVENT, THEN WITH A NON-POLAR ORGANIC SOLVENT AND FINALLY DRYING THE MEMBRANE. THE PRESENCE OF A WATER-SOLUBLE POLYOL IN THE DRY MEMBRANE RESULTS IN STILL BETTER PROPERTIES.

Journal ArticleDOI
TL;DR: In this paper, an enrichment in the polar solvent in the shell of polar solutes is described quantitatively by the balance between dipole-dielectric stabilization and the change in entropy.

Journal ArticleDOI
TL;DR: Phenyl-substituted polyquinoxalines of unusually high oxidative-thermal stability were prepared by one-step solution condensations of aromatic tetraamines as discussed by the authors.
Abstract: Phenyl-substituted polyquinoxalines of unusually high oxidative-thermal stability were prepared by one-step solution condensations of aromatic tetraamines with 1,4-bis-(phenylglyoxaloyl)benzene and 1,3-bis(phenylglyoxaloyl)benzene. The final polymers thus obtained show exceptionally good solubility in a variety of common organic solvents, such as chloroform, tetrachloroethane, dichlorobenzenes, and certain phenols. Polymerizations in these solvents lead to polyquinoxalines of high molecular weight at reaction rates which depend upon the solvent used. The phenylated polyquinoxalines exhibited glass transition temperatures between 253 and 317°C and polymer decomposition temperatures between 515 and 540°C, depending upon structure. Isothermal decomposition at 400°C in air showed a strong dependency of weight loss on structure. Tough, flexible films were cast from solutions.

Journal ArticleDOI
TL;DR: In this article, a solution containing polar solvent such as pyridine, quinoline, dioxane, dimethylformamide, and dimethylsulfoxide derivatives was converted to an equimolar amount of inorganic sulfate and corresponding amine.
Abstract: In a solution containing the polar solvent such as pyridine, quinoline, dioxane, dimethylformamide, and dimethylsulfoxide, sulfamic acid and its N-substituted derivatives were converted to an equimolar amount of inorganic sulfate and corresponding amine. The factors and the reaction mechanisms concerning this degradation process were discussed on the basis of the experimental results, and the following scheme of the reaction was proposed : [chemical formula] It was also proved that this reaction and the determination procedures is possible to apply as the general analytical method for sulfamic acid derivatives.

Journal ArticleDOI
TL;DR: The iodination of insulin was studied under various experimental conditions in aqueous media and in some organic solvents, by measuring separately the uptake of iodine by the four tyrosyl groups and the relative amounts of monoiodotyrosine and di-iodotYrosine that are formed.
Abstract: 1. The iodination of insulin was studied under various experimental conditions in aqueous media and in some organic solvents, by measuring separately the uptake of iodine by the four tyrosyl groups and the relative amounts of monoiodotyrosine and di-iodotyrosine that are formed. In aqueous media from pH1 to pH9 the iodination occurs predominantly on the tyrosyl groups of the A chain. Some organic solvents increase the iodine uptake of the B-chain tyrosyl groups. Their efficacy in promoting iodination of Tyr-B-16 and Tyr-B-26 is in the order: ethylene glycol and propylene glycol approximately methanol and ethanol>dioxan>8m-urea. 2. It is suggested that each of the four tyrosyl groups in insulin has a different environment: Tyr-A-14 is fully exposed to the solvent; Tyr-A-19 is sterically influenced by the environmental structure, possibly by the vicinity of a disulphide interchain bond; Tyr-B-16 is embedded into a non-polar area whose stability is virtually independent of the molecular conformation; Tyr-B-26 is probably in a situation similar to Tyr-B-16 with the difference that its non-polar environment depends on the preservation of the native structure.


Journal ArticleDOI
TL;DR: In this article, an equation relating the R M value of a proton donor solute with the composition of a binary developing solvent system of the type electron donor solvent + neutral diluting solvent was derived.