Extraction of microamounts of caesium into different organic solvents in the presence of sodium dipicrylaminate

A study has been made of the extraction of microamounts of caesium from the aqueous phase into 28 organic solvents in the presence of sodium dipicrylaminate and nitrate, and the extraction of macroamounts of ceasium and rubidium dipicrylaminates from nitrobenzene and nitromethane into some other organic solvents. The equilibrium constants of the reaction Cs _a ⁺ +Na _O ⁺ =Cs _O ⁺ +Na _a ⁺ were determined and a correlation with the water content of the organic phase has been discussed.     

Fluorine‐containing vinyl ether polymers: Living cationic polymerization in fluorinated solvents as new media and unique solubility characteristics in organic solvents

Living cationic polymerization of fluorine‐containing vinyl ethers [CH₂?CH? O? C₂H₄? O? C₃H₆? C_nF_2n+1: 5FVE (n = 2), 13FVE (n = 6)] was investigated in various solvents with a CH₃CH(OiBu)OCOCH₃/Et_1.5AlCl_1.5 initiating system in the presence of an added base. 5FVE was polymerized quantitatively in toluene at 0 °C, and the obtained polymers had predetermined molecular weights with narrow molecular weight distributions (M_w/M_n < 1.1). On the other hand, for the polymerization of 13FVE, the product polymers precipitated due to their extremely poor solubility in nonfluorinated organic solvents. Therefore, fluorinated solvents such as hydrochlorofluorocarbons, hydrofluorocarbons, hydrofluoroethers, or α,α,α‐trifluorotoluene, as‐yet uninvestigated for cationic polymerization, were employed. In these solvents, living polymerization was achieved even with 13FVE, yielding well‐defined polymers (M_w/M_n < 1.1, by size exclusion chromatography using a fluorinated solvent as an eluent). The solvents were also shown to be good for living polymerization of isobutyl vinyl ether. The obtained fluorine‐containing polymers underwent temperature‐responsive solubility transitions in organic solvents. Poly(5FVE) showed sensitive upper critical solution temperature (UCST)‐type phase separation behavior in toluene. Copolymers of 13FVE and isobutyl vinyl ether showed UCST‐type phase separation in common organic solvents with different polarities depending on their composition, while a homopolymer of 13FVE was insoluble in all nonfluorinated organic solvents. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Reverse Vesicles of Ferrum Laurate Metallosurfactant in Non‐Aqueous Solution Dried to Produce Solid Shells

Ferrum laurate [Fe(OOCC₁₁H₂₃)₃] metallosurfactant can successfully self‐assemble into reversed vesicles in organic media such as pure CHCl₃ and a mixed solvent of CHCl₃ and CH₃OH. Deformed solid vesicles, including collapsed erythrocyte‐like and broken hollow shells, were obtained directly by slectively drying the organic solvents. The morphology of the reversed vesicles of metallosurfactant in the organic media to hardly solid shells is maintained and it is ascribed to the evaporation rate of the solvents and the interactions between ferrum laurate and solvents.     

Effects of organic solvents on the structure stability of TS-1 for the ammoximation of cyclohexanone

The effects of organic solvents on the ammoximation of cyclohexanone to cyclohexanone oxime with H₂O₂and NH₃ over TS-1 were studied. To investigate the effects of ammonia and organic solvents on the structure stability of the catalyst, TS-1 samples were pretreated under severe conditions in ammonia solution or ammonia solution plus methanol, toluene or t-butanol, respectively, and then characterized bySEM, XRD, FTIR, etc. The results revealed that t-butanol is the best solvent for the ammoximation reaction; ammonia tends to destroy the active sites, -Ti-O-Si- structure in TS-1, but the presence of organic solvents remarkably limits this damaging effect of ammonia.     

Biochemical Properties and Potential Applications of a Solvent-Stable Protease from the High-Yield Protease Producer <Emphasis Type="Italic">Pseudomonas aeruginosa</Emphasis> PT121

An organic solvent-stable protease from Pseudomonas aeruginosa PT121 was purified in a single step with 55% recovery by hydrophobic interaction chromatography on a Phenyl Sepharose High Performance matrix. The purified protease was homogenous on SDS-PAGE and had an estimated molecular mass of 33 kDa. The optimal pH and temperature conditions for enzyme activity were 8.0 and 60°C, respectively. The enzyme was classified as a metalloprotease based on its strong inhibition by EDTA and 1,10-phenanthroline and exhibited good stability across a broad pH range (6.0–11.0). The protease was quite stable in the presence of various water-miscible organic solvents. This is a unique property of the protease which makes it an ideal choice for application in aqueous-organic phase organic synthesis including peptides synthesis. The synthetic activity of the protease was tested using N-carbobenzoxy-l-asparagine (Z-Asp) and l-phenylalaninamide (Phe-NH₂) as substrate in the presence of various water-miscible organic solvents for aspartame precursor synthesis. The highest yield was obtained in the presence of 50% DMSO (91%). The synthesis rate in the presence of DMSO was also much higher than the rates in the other tested organic solvents, and the initial rates of Z-Asp-Phe-NH₂ synthesis in mixtures of various water-miscible organic solvents, with the exception of ethanol, correlated with the yields of Z-Asp-Phe-NH₂. Furthermore, the PT121 protease was able to use various carboxyl components (Z-AA) and Phe-NH₂ as substrates to catalyze the syntheses of the dipeptides, indicating that this protease has a broad specificity for carboxylic acid residue.     

Gelation of a Highly Fluorescent Urea‐Containing Triarylmelamine Derivative: 2,4,6‐Tris(p‐N′‐Octadecylureido‐Anilino)Triazine in Organic Solvents

A new gelator of urea‐containing triazine derivatives was synthesized and tested in order to explore the gelation potential in different organic solvents. This compound has been found to form organogels with a variety of organic solvents such as decalin and other solvents. The resulting thermo‐reversible gel was characterized by using the dropping ball method and a number of other instruments. The melting temperature of the gel increased with the gel concentration. The intermolecular hydrogen bonding of gelation was demonstrated through an FT‐IR spectrometer. UV‐Vis and fluorescence analysis showed that the gel displayed various optical effects in different organic solvents. The blue fluorescence of the gel in decalin and the quenched effect of gel in CHCl³ were displayed, respectively. Morphological features in decalin and CHCl₃ were studied by applying atomic force microscopy (AFM), and the morphological features demonstrated that there were different aggregations in different solvents. In conductivity electrolyte experiments, the organogel electrolytes indicated high conductivity (σ) comparable to the corresponding NaClO₄/THF solution. The conductivity of gel electrolytes was increased with electrolyte salt.     

On Acidic Organodiphosphorus Extractants. Part V. Extraction Dependency of Trivalent Europium on the Dielectric Constant of the Organic Phase

Abstract

The extraction of Eu(III) has been carried out from a 1 M (H,Na)Clo₄ solution into different organic solvents at constant total concentration (6.67 × 10^?3 M) of the extractant, di-n-butyl-ethane-(l,2)-diphosphonic acid (H₂B₂-EDP). The distribution coefficient of Eu(III) is influenced quite appreciably by the nature of the organic solvent. We observe that the distribution coefficient can vary by a factor of 10⁶ for two solvents such as chloroform and ieo-octane. The experimental results are compared with those of Dréze¹, who used di-n-butyl-phosphoric acid (HDBP) for the extraction of Eu(lII) into different organic solvents. If we assume that H₂-B₂-EDP remains monomer for a total concentration of 6.67 × 10^?3 M in the solvents used², then we may conclude that the extraction of Eu(III) by the associated HDBP or the monomer H₂B₂EDP is influenced in the same manner in the solvents used.     

Laser induced photoacoustic spectroscopy in liquid samples: temperature and solvent effects

Summary Laser induced photoacoustic spectroscopy (LIPAS) has been confirmed as an analytical tool, suitable for the determination of inorganic and organic species in aqueous and organic solvents, reaching detection limits two orders of magnitude lower than those obtained with conventional spectrophotometry.A significant influence of the solvent on the enhancement of the magnitude of the LIPAS response waveform of the piezoelectric detector has been found experimentally for inorganic species (neodymium ions) and organic compounds (e.g. -carotene and the cytochrome c), when water was replaced by organic solvents. This is particularly true, when a laser excitation wavelength above 500 nm was used, where the absorption coefficient for H₂O increases drastically.Furthermore, the temperature dependence of the magnitude of the LIPAS signal has been measured, in the range between 20–70°C in samples containing Nd³⁺,-carotene and the macromolecule cytochrome c in various aqueous and organic (polar and non-polar) solvents (H₂O, HClO₄, acetone, ethanol and petrol ether). A very strong enhancement of the LIPAS response was observed with increasing temperature (a factor of two in an interval between 20 and 40°C) for all inorganic and organic substances in aqueous solution. On the other hand, in polar and non-polar organic solvents only a slight decline of the signals of about 20% was found over the same temperature range.     

Phosphine-free synthesis of metal chalcogenide quantum dots by means of in situ-generated hydrogen chalcogenides

We proved that various organic solvents react with elemental chalcogens (sulfur and selenium) by liberating hydrogen chalcogenide (H₂X, X = S, Se) during the phosphine-free hot-matrix synthesis of quantum dots. The in situ-produced H₂X reacts further with the metal salt to form the corresponding nanosized metal chalcogenide CdX. The effect of temperature on the rate of H₂X generation was quantitatively studied in various organic solvents. We found that the organic amines reduce the reaction temperature of the phosphine-free quantum dots synthesis, being more effective in situ generators of H₂S than the other tested organics at relatively low temperatures (140–170 °C).     

Solution polymerization of methyl methacrylate using trioctylmethylammonium persulfate initiator: Kinetics of polymerization and activation parameters for the primary decomposition of the initiator

The kinetics of solution polymerization of methyl methacrylate using trioctylmethylammonium persulfate (aliquat persulfate) at 60°C has been studied in t-butyl alcohol, N,N-dimethyl formamide, acetonitrile, dioxane, acetone, and methyl ethyl ketone. The rate of polymerization depends markedly on the solvent used. The initiator exponent is close to 0.5 in the first three solvents but larger than this value in the other three solvents. The overall activation energy of the polymerization has been determined in all the solvents. The rate constants and activation parameters for the primary decomposition of the initiator have been determined in the first three solvents where ideal polymerization conditions prevail. The activation parameters for the decomposition of AQ₂S₂O₈ in the organic solvents depend on the type of solvent. They are very different from those of the free S₂O^2?₈ ion in water. These differences have been explained taking into consideration the various ionic forms in which the initiator exists in the studied solvents using a previously postulated model of the activated state.     

New gelators of urea-containing triazine derivatives: effects of aggregation and optical features in different organic solvents

New gelators for urea-containing triazine derivatives were synthesised, and their gelation potential was examined using different organic solvents. These compounds were found to form the organogels with a variety of organic solvents, such as hexane and other solvents. The elongated alkyl tails of the gelators displayed an obvious decrease in the critical gelation concentrations of apolar solvents and an increase in the compatibility of gelation in polar solvents. The resulting thermo-reversible gels were characterised by using the dropping ball method and a number of other instruments. The melting temperature (Tm) of the gels in decalin and CCl₄ increased with the gelator concentrations. The intermolecular hydrogen bonding of gelation in different organic solvents was observed using an FT-IR spectrometer. Temperature-dependent UV–vis and fluorescence analysis showed that the organogels displayed diverse aggregations and various fluorescence effects in different organic solvents. Blue fluorescence and J-aggregation in decalin and the quenched effect and π–π stacking in CCl₄ were observed. Further, the morphological self-assembled feature in different organic solvents was studied with a scanning electron microscope, and the morphological features demonstrated that there were different aggregations in different solvents. In conductivity electrolyte experiments, the organogel electrolytes exhibited high conductivity (σ) compared with the corresponding tetrabutylammonium perchlorate (TBAP)/THF solution. The conductivity of the gel electrolytes increased with the concentration of the electrolyte salts and temperature. When the sol–gel temperature was achieved, a high ion conductivity was observed compared with the corresponding TBAP/THF solution. When the ratio of the added electrolyte salts exceeded 5%, gelation was inhibited. Furthermore, the effect of the electrolyte salts on the Tm of the gel was confirmed. The added electrolyte salts affected the gelation ability, but did not affect the sol–gel temperature.     

Oriented free-standing ammonium vanadium oxide nanobelt membranes: highly selective absorbent materials

Highly selective, absorbent, free‐standing, paper‐like membranes made of ammonium vanadium oxide (NH₄V₄O₁₄) nanobelts have been engineered by taking advantage of the nanoscaled self‐assembly of architectures that display a mesh structure with an average periodic pore size of about 5 to 10 nm. The NH₄V₄O₁₄ nanobelts are synthesized by using a simple hydrothermal process, and exhibit the same orientation and assemble into bundles, each about 40 to 80 nm in width, 3 to 5 nm in thickness, and up to several millimeters in length. Importantly, the as‐obtained NH₄V₄O₁₄ nanobelt membranes can highly selectively absorb a variety of organic solvents, covering both polar and non‐polar solvents, for example, the absorbent capacity of glycol is 28 times as high as the initial weight of the membrane, and it can even separate organic solvents with similar polarities and absorb solid contaminants in organic solvents. These highly selective, absorbent membrane materials can be an ideal candidate for the separation and removal of pollution in industrial and environmental applications.     

Autoxidation of cyclic olefins in perfluorinated organic solvents

It is well known that several perfluorinated organic compounds (particularly alcanes and cyclic ethers perfluor$\text{i}$nated) have specific properties like solvents of biatomic gas and oxygen.Since these perfluorinated compounds have also suff$\text{i}$cient capabilities as solvents of several alifatic hydr$\text{o}$carbons and pratically none as solvents of their oxidation products (alcohols, ketones; peroxides, acids, water, etc.), these solvents seem ideal for the studying of oxidation reactions in liquid phase.The kinetics of autoxidation, with O₂ for temperatures between 15°C and 60°C, of cyclohexene and methyl cyclohexenes, have been studied in fluorinated solvents (various mixtures of 3,n-perfluoro-propyl-perfluoro-tetrahydrofuran, and 3,n-perfluoro-buthyl-perfluoro-tetrahydropyran) with formula C₈F₁₆O. This study includes the determination of the kinetic parameters both during the induction phase and during the stationary phase.The above mentioned oxidations we have studied in anal$\text{o}$gous conditions in other solvents (carbon tetrachloride, benzene chloride, etc.). The highest rates observed and the larger selectivity of the fluorinated solvents have been pointed out.     

Ring-opening metathesis polymerization (ROMP) of fullerene-containing monomers in the presence of a first-generation Grubbs catalyst

New norbornene-type monomers containing covalently bound C60 fullerene have been obtained. In the presence of the 1st generation Grubbs catalyst [(PCy₃)₂Cl₂RuCHPh] (Cy is cyclohexyl), these monomers smoothly undergo homopolymerization and copolymerization with parent fullerene-free monomers. The homopolymers are insoluble in common organic solvents, while the copolymers obtained at different molar ratios to their fullerene-free analogues are very soluble in organic solvents and can be suitable for the preparation of thin films.     

CO2-expanded bio-based liquids as novel solvents for enantioselective biocatalysis

For the first time, CO₂-expanded bio-based liquids were reported as novel and sustainable solvents for biocatalysis. Herein, it was found that by expansion with CO₂, 2-methyltetrahydrofuran (MeTHF), and other bio-based liquids, which were not favorable solvents for immobilized Candida antarctica lipase B (Novozym 435) catalyzed transesterification, were tuned into excellent reaction media. Especially, for the kinetic resolution of challenging bulky secondary substrates such as rac-1-adamantylethanol, the lipase displayed very high activity with excellent enantioselectivity (E value > 200) in CO₂-expanded MeTHF (MeTHF concentration 10% v/v, 6 MPa), whereas there was almost no activity observed in conventional organic solvents.     

Covalent modification of mushroom tyrosinase with different amphiphic polymers for pharmaceutical and biocatalysis applications

Two different poly(ethylene glycol) derivatives (linear, mol wt 5000 and a branched form, mol wt 10000) and a new polymer (poly [acryloylmorfoline], mol wt 5500) were covalently bound to the enzyme tyrosinase. The polymer-protein conjugates were studied with a view to their potential pharmaceutical application and to their use for the bioconversion of phenolic substrates in organic solvents.V _max andK _m for the dopa-dopaquinone conversion, thermostability, stability toward inactivation by dopa oxidation products, half-life in blood circulation, and behavior in organic solvents for the different adducts were investi gated. Arrhenius plots for the dopa-dopaquinone conversion were also obtained in order to study the effects of temperature on the different enzyme forms. Covalent attachment of the polymers increased enzyme stability in aqueous solution and the solubility in organic solvents. However, organic solvent solubilization brought about loss of enzyme conformation as assessed by CD measurements, which is accompanied by a nonreversible loss of catalytic activity.     

Interaction Between Surface Active Solutes and Surfaces of Metal Oxides in Polar Organic Solvents

Ionic surfactants are efficient as charge-controlling agents in very polar and in completely non-polar solvents. On the other hand in polar organic solvents of dielectric constants of about 25, the effect of ionic surfactants on the ζ potential is often insignificant. Weak acids can be used to control the ζ potential of TiO₂ in solvents, in which ionic surfactants are not efficient. Phosphoric acid alone and combined with bases is useful as charge-controlling agent in aliphatic alcohols and in DMSO.     

Rate constants for reaction of 1,2‐dimethylimidazole with benzyl bromide in ionic liquids and organic solvents

The rate constant for the Menschutkin reaction of 1,2‐dimethylimidazole with benzyl bromide to produce 3‐benzyl‐1,2‐dimethylimidazolium bromide was determined in a number of ionic liquids and molecular organic solvents. The rate constants in 12 ionic liquids are in the range of (1.0–3.2) × 10^?3 L mol^?1 s^?1 and vary with the solvent anion in the order (CF₃SO₂)₂ N^? < PF₆^? < BF₄^?. Variations with the solvent cation (butylmethylimidazolium, octylmethylimidazolium, butyldimethylimidazolium, octyldimethylimidazolium, butylmethylpyrrolidinium, and hexyltributylammonium) are minimal. The rate constants in the ionic liquids are comparable to those in polar aprotic molecular solvents (acetonitrile, propylene carbonate) but much higher than those in weakly polar organic solvents and in alcohols. Correlation of the rate constants with the solvatochromic parameter E _T(30) is reasonable within each group of similar solvents but very poor when all the solvents are correlated together. Better correlation is obtained for the organic solvents by using a combination of two parameters, π* (dipolarity/polarizibility) and α (hydrogen bond acidity), while additional parameters such as δ (cohesive energy density) do not provide any further improvement. © 2004 Wiley Periodicals, Inc. *

1 This article is a US Government work and, as such, is in the public domain of the United States of America.

Int J Chem Kinet 36: 253–258, 2004     

Amorphous celluloses stable in aqueous media: Regeneration from SO2–amine solvent systems

Amorphous celluloses were prepared by regeneration of cellulose from its solutions in the SO₂–diethylamine–dimethylsulfoxide (SO₂–DEA–DMSO) solvent system, and other selected SO₂–amine–organic solvents. The celluloses were amorphous whether regenerated in water or in alcohols or other organic solvents; in this respect the observations differ from all prior experience in the regeneration of cellulose. These celluloses retain their amorphous character even after extended soaking in water at room temperature. Viscosity measurements have shown that little or no depolymerization occurs during the dissolution, regeneration, and drying processes. Thus the procedures allow the preparation of amorphous celluloses of a wide range of molecular weights for use to model the behavior of amorphous domains in fibrous celluloses. The unusual stability of the amorphous cellulose structures prepared by these procedures is attributed to very rapid decomposition of the SO₂–amine complex with the cellulosic hydroxyl groups which is believed to occur in the solvated state. The rate of decomposition of this complex appears to be sufficiently high so that the cellulose chains aggregate in an amorphous state before they have any opportunity to realign into crystalline domains.     

Fluorinated vinyl ether homopolymers and copolymers: Living cationic polymerization and temperature‐induced solubility transitions in various organic solvents including perfluoro solvents

Partially fluorinated poly(vinyl ether)s with C₄F₉ and C₆F₁₂H groups in the side chain were synthesized via living cationic polymerization in the presence of an added base in a fluorine‐containing solvent, dichloropentafluoropropanes. For comparison, the polymerization of vinyl ether monomers with C₂F₅ and C₆F₁₃ groups and nonfluorinated monomers were also carried out. The characterization of the product polymers using size exclusion chromatography with a fluorinated solvent as an eluent indicated that all polymers had narrow molecular weight distributions (M_w/M_n ～ 1.1). Interestingly, the moderately fluorinated polymers with C₄F₉ exhibited upper critical solution temperature‐type phase separation in various organic solvents with wide‐ranging polarities, whereas highly fluorinated polymers with C₆F₁₃ are insoluble in nonfluorinated solvents. Polymers with C₄F₉ groups exhibited temperature dependent solubility transitions not only in common organic solvents (e.g., toluene, chloroform, tetrahydrofuran, and acetone) but also in perfluoro solvents [e.g., perfluoro(methylcyclohexane) and perfluorodecalin]. On the other hand, the solubility of polymers with C₆F₁₂H showed completely different from that of polymers with C₆F₁₃, despite their similar fluorine content. In addition, various types of fluorinated block copolymers were prepared in a living manner. The block copolymers with a thermosensitive fluorinated segment underwent temperature‐induced micellization and sol–gel transition in various organic solvents. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011