Tetrabutylphosphonium Bromide Research Articles

Efficient Ring Opening Reaction of Epoxides with Oxygen Nucleophiles Catalyzed by Quaternary Onium Salt

Ring opening reactions of epoxides with oxygen nucleophiles catalyzed by a variety of quaternary onium salt, such as ammonium or phosphonium salt were explored. The results showed that tetrabutylphosphonium bromide (TBPB) among salts serves as the most efficient catalyst for this process and that expoxide ring opening reactions with a variety of oxygen nucleophiles including carboxyic acid and phenol, promoted using this salt, lead to generate readily purifiable products in excellent yields.

Phase Equilibrium Data of Tetrabutylphosphonium Bromide Plus Carbon Dioxide or Nitrogen Semiclathrate Hydrates

In this paper, phase equilibrium data of tetrabutylphosphonium bromide (TBPB) + CO2, + N2 semiclathrate hydrates were measured by employing an isochoric pressure-search method. The experimental temperature, pressure, and mass fraction of TBPB ranged from (282.2 to 292.0) K, from (1.32 to 16.86) MPa, and from (0.050 to 0.600), respectively. The results demonstrated that at a given pressure, the temperature required to form mixed TBPB + CO2, + N2 hydrates was significantly higher than that required for forming pure CO2 or N2 hydrates. In addition, the application of TBPB at 0.371 mass fraction, corresponding to TBPB·32H2O, showed the strongest stabilization effect.

Accurate DSC measurement of the phase transition temperature in the TBPB–water system

There is some disagreement in the literature on the phase transition temperatures of salt semi-clathrates, which melt incongruently due to the change of salt concentration in the liquid phase. By using differential scanning calorimetry (DSC), the phase transition temperatures of tetrabutylphosphonium bromide (TBPB) hydrates were investigated at 0.10<wTBPB<0.37 and atmospheric pressure. The freezing point of ice with the presence of NaCl was also studied as a reference. In this work, two DSC procedures were employed: dynamic and stepwise schemes, characterized by the maximum peak temperature Tpeak and inflection point temperature Tend, and final step temperature Tstep, respectively. The stepwise DSC scheme was validated by the measurement of the ice freezing point at wNaCl=0.10, 0.15 and 0.18. For the dynamic scheme, we developed and tested a method to estimate the melting temperature of TBPB hydrates. This method, though having a higher uncertainty, was more efficient than the stepwise scheme. The phase transition temperatures of TBPB hydrates are presented with the accuracy of 0.1K and compared with literature data.

Phase equilibrium for ionic semiclathrate hydrate formed with CO2, CH4, or N2 plus tetrabutylphosphonium bromide

The article describes the equilibrium conditions for the semiclathrate hydrates formed in the following three ternary systems, CO2+tetrabutylphosphonium bromide+water system, CH4+tetrabutylphosphonium bromide+water system, and N2+tetrabutylphosphonium bromide+water system. The experiments were performed at temperatures between 282.6 and 291.6K, at pressures between 0.15 and 5.10MPa with tetrabutylphosphonium bromide aqueous solution of wTBPB=0.35, where wTBPB denotes the mass fraction of tetrabutylphosphonium bromide, respectively. The equilibrium pressure at a given temperature was lower in the order of CO2, CH4 and N2 thereby indicating the possibility of capturing CO2 from the CH4+CO2 and N2+CO2 mixtures.

Phase equilibria of toluene/heptane with tetrabutylphosphonium bromide based deep eutectic solvents for the potential use in the separation of aromatics from naphtha

In this work, new solvents are introduced to conduct the task of removing aromatic hydrocarbons from the feed stream to ethylene cracker. Liquid–liquid equilibrium (LLE) data for ternary systems of toluene and heptane with two newly introduced deep eutectic solvents (DESs) were estimated experimentally at 40, 50 and 60°C and atmospheric pressure. The DESs are made from tetrabutylphosphonium bromide as salt and either ethylene glycol or sulfolane as hydrogen bond donor (HBD). The reliability of the LLE data were ascertained by applying the Othmer–Tobias and Hand correlations. The non-random two liquid (NRTL) model was used to correlate the experimental tie-lines and to calculate the phase compositions of the ternary systems. The results showed a very good agreement between calculated and experimental compositions. Further LLE data are presented to estimate the improvement of the separation by changing the salt:HBD molar ratio used to synthesize the DES at 30, 40, 50 and 60°C. This work illustrates the possibility of applying these two DESs as solvents for this extraction task.

Thermodynamic properties of ionic semiclathrate hydrate formed with tetrabutylphosphonium bromide

This paper reports an experimental study to measure the thermodynamic properties of ionic semiclathrate hydrate formed with tetrabutylphosphonium bromide. The thermodynamic measurements were performed on the temperature–composition phase diagram of the hydrate in the range of the mass fraction of tetrabutylphosphonium bromide wTBPB from 0.10 to 0.50 and the hydrate dissociation enthalpy, where wTBPB denotes the mass fraction of tetrabutylphosphonium bromide. The highest equilibrium temperature for tetrabutylphosphonium bromide hydrate was 282.4K at 0.33≤wTBPB≤0.35. Dissociation enthalpy was measured to be 214kJ/kg at wTBPB=0.35 with a differential scanning calorimetry. An attempt was made to determine the crystallographic structure of the tetrabutylphosphonium bromide hydrate by single-crystal X-ray diffraction measurements.

Phosphonium-based ionic liquids as modifiers for biomedical grade poly(vinyl chloride)

This work reports and discusses the influence of four phosphonium-based ionic liquids (PhILs), namely trihexyl(tetradecyl) phosphonium dicyanamide, [P6,6,6,14][dca]; trihexyl(tetradecyl) phosphonium bis(trifluoromethylsulfonyl)imide, [P6,6,6,14][Tf2N]; tetrabutyl phosphonium bromide, [P4,4,4,4][Br]; and tetrabutyl phosphonium chloride, [P4,4,4,4][Cl], on some of the chemical, physical and biological properties of a biomedical-grade suspension of poly(vinyl chloride) (PVC). The main goal of this work was to evaluate the capacity of these PhILs to modify some of the properties of neat PVC, in particular those that may allow their use as potential alternatives to traditional phthalate-based plasticizers in PVC biomedical applications. PVC films having different PhIL compositions (0, 5, 10 and 20wt.%) were prepared (by solvent film casting) and characterised by Fourier transform infrared, thermogravimetric analysis, differential scanning calorimetry, dynamical mechanical thermal analysis, scanning electron microscopy/energy-dispersive X-ray/electron probe microanalysis, X-ray diffraction, transmittance, permeability towards oxygen and carbon dioxide, thermal degradation, contact angle measurement, water and vapour uptake, leachability and biocompatibility (haemolytic potential, thrombogenicity and cytotoxicity). A conventional organic plasticizer (di-isononyl phthalate) was used for comparison purposes. The results obtained showed that it was possible to change the neat PVC hydrophobicity, and consequently its water uptake capacity and plasticizer leachability, just by changing the PhIL employed and its composition. It was also possible to significantly change the thermal and mechanical properties of PVC films by choosing appropriate PhIL cation/anion combinations. However, a specific PhIL may not always be capable of simultaneously keeping and/or improving both physical properties. In addition, ionic halide salts were found to promote PVC dehydrochlorination. Finally, none of the prepared materials presented toxicity against Caco-2 cells, though pure [P6,6,6,14][dca] decreased HepG2 cells viability. Moreover, PVC films with [P6,6,6,14][dca] and [P4,4,4,4][Cl] were found to be haemolytic and thus these PhILs must be avoided as PVC modifiers if biomedical applications are envisaged. In conclusion, from all the PhILs tested, [P6,6,6,14][Tf2N] showed the most promising results regarding blood compatibility, leaching and permeability to gases of PVC films. The results presented are a strong indicator that adequate PhILs may be successfully employed as PVC multi-functional plasticizers for a wide range of potential applications, including those in the biomedical field.

ChemInform Abstract: One‐Pot Synthesis of Pyrano‐ and Furanoquinolines Catalyzed by Molten Tetra‐n‐butylphosphonium Bromide under Solvent‐Free Conditions.

AbstractMolten tetrabutylphosphonium bromide is found to be a practical catalytic media for diastereoselective one‐pot synthesis of furano‐ and pyranoquinoline derivatives.

Highly efficient chemical fixation of carbon dioxide catalyzed by high-valent tetraphenylporphyrinatotin(IV) triflate

Abstract High-valent tetraphenylporphyrinatotin(IV) triflate, [Sn IV (TPP)(OTf) 2 ], was found as an efficient catalyst for the coupling of several epoxides (linear and cyclic) with carbon dioxide in the presence of tetrabutylphosphonium bromide as co-catalyst at atmospheric pressure. The reaction temperature, kind of solvent, co-catalyst and axial ligand effect were also investigated.

Experimental Data on Phase Behavior of Simple Tetrabutylphosphonium Bromide (TBPB) and Mixed CO2 + TBPB Semiclathrate Hydrates

The phase behavior of simple and mixed semiclathrate hydrates formed from CO2 + tetrabutylphosphonium bromide (TBPB) + water mixtures was investigated by pressure-controlled differential scanning calorimetry (DSC) at TBPB concentrations in the range of 0 to 0.073 mole fraction and at CO2 pressure in the range of (0 to 2.0) MPa. In a previous article we demonstrated that TBPB + CO2 mixed hydrates present high dissociation enthalpies and could be used as phase change material, covering the range of temperature from (284.6 to 289.0) K, for secondary refrigeration applications. The present work investigates a broader domain of compositions, resulting in x–T phase diagrams at atmospheric conditions and at various CO2 pressures. These data are required to model the potential latent heat of hydrate slurries as a function of gas pressure and aqueous phase composition over the whole range of interest for refrigeration purposes. The results presented show that adding TBPB to the water at low concentration (0.0058 m...

Electron-deficient tin(IV)tetraphenylporphyrin perchlorate: A highly efficient catalyst for chemical fixation of carbon dioxide

Electron-deficient tin(IV)tetraphenylporphyrin perchlorate, [Sn IV(TPP)(ClO 4) 2] was used as a highly efficient catalyst for chemical fixation of carbon dioxide. The bifunctional catalytic system [Sn(TPP)(ClO 4) 2]/tetrabutylphosphonium bromide (TBPB) was applied for preparation of cyclic carbonates from epoxides and carbon dioxide. The effect of reaction parameters was also investigated.

Measuring concentration depth profiles at liquid surfaces: Comparing angle resolved X-ray photoelectron spectroscopy and neutral impact collision scattering spectroscopy

Measuring concentration depth profiles is important for analyzing surfaces. The surface excess, the change in concentration from the surface to the bulk and separation of the constituents are some of the features that can be derived from concentration depth profiles and are most important in particular for analyzing liquid surfaces. Angle resolved X-ray photoelectron spectroscopy (ARXPS) and neutral impact collision ion scattering spectroscopy (NICISS) are methods used for determining concentration depth profiles at liquid surfaces. Here we compare concentration depth profiles determined with both methods from the constituents of a solution of the ionic surfactant tetrabutylphosphonium bromide in the polar solvent formamide. ARXPS is performed with a laboratory X-ray source and NICISS with 4.5 keV helium ions. Agreement is found in the surface excess and in the shape of the cation concentration depth profiles. Disagreement was found in the shape of the anion concentration depth profiles. The separation of charges as found with NICISS for projectiles with low kinetic energies could not be reproduced. The advantages of each of the methods and the criteria for selecting the projectile energy in NICISS are discussed.

Apparent molar volumes and compressibilities of tetrabutyl-ammonium bromide in organic solvents

The densities of tetra- n-butylammonium bromide in 1-propanol, 1-butanol, acetone at (288.15, 293.15, 298.15, 303.15, 308.15, 313.15, and 323.15) K and sound velocities at 298.15 K have been measured. From these data apparent molar volumes V Φ at (288.15, 293.15, 298.15, 303.15, 308.15, 313.15, and 323.15) K and the apparent molar isenotropic compressibility K S , Φ , at T = 298.15 K of tetrabutylammonium bromide in nonaqueous solvents have been determined. The apparent molar volumes and the apparent molar isenotropic compressibilities were fitted to the Redlich, Rosenfeld, and Mayer equation as well as to the Pitzer equation yielding infinite dilution data, which were compared to the similar quantities for tetrabutylphosphonium bromide. Moreover, the acoustical parameters such as intermolecular free length ( L f ), relative association ( R A ), Rao’s molar sound function ( R m ), and salvation number ( S n ) were calculated using the experimental data of density and sound velocity at T = 298.15 K for ammonium and phosphonium bromides. The obtained data suggest the penetration of the acetone molecule within the intraionic free space of the tetrabutyl-ammonium and phosphonium cations.

Activity and stability of α-chymotrypsin in biocompatible ionic liquids: enzyme refolding by triethyl ammonium acetate

In view the of wide scope of structural information of biomolecules in biocompatible ionic liquids (ILs) in various applications including chemical and biochemical, it is essential to study the productive preferential interactions between biological macromolecules and biocompatible ILs. We have therefore explored the stability and activity of α-chymotrypsin (CT) in the presence of five ILs from different families, such as triethyl ammonium acetate (TEAA), triethyl ammonium phosphate (TEAP) from ammonium salts, 1-benzyl-3-methylimidazolium chloride ([Bzmim][Cl]), 1-benzyl-3-methylimidazolium tetrafluoroborate ([Bzmim][BF(4)]) from imidazolium salts and tetra-butyl phosphonium bromide (TBPBr) from phosphonium families. Circular dichroism (CD) and UV-vis spectrophotometer experiments were used to study CT stabilization by ILs, related to the associated structural changes and enzyme activity studies, respectively. We observed that all ILs have a dominant contribution to the stabilization of CT. The stability and activity of CT depends on the structural arrangement of the ions of ILs. Our experimental results explicitly elucidate that more hydrophobic imidazolium and phosphonium cations carrying longer alkyl chains of ILs ([Bzmim][Cl], [Bzmim][BF(4)] and TBPBr) were weak stabilizers for CT, while small alkyl chain molecules of triethyl ammonium salts (TEAA and TEAP) are strong stabilizers and therefore more biocompatible for CT stability. Our CD and NMR measurements reveal that TEAA is a refolding additive for CT from a quenched thermal unfolded enzyme structure.

A quantitative structure-activity relationship study of tetrabutylphosphonium bromide analogs as muscarinic acetylcholine receptors

Quantitative structure-activity relationship (QSAR) of tetrabutylphosphonium bromide (TBPB) analogs as muscarinic acetylcholine receptors (mAChRs) was studied. A suitable set of molecular descriptors was calculated and stepwise multiple linear regression (SW-MLR) was employed to select those descriptors that resulted in the best fitted models. A MLR model with three selected descriptors was obtained. Furthermore, the MLR model was validated using the leave-one-out (LOO) and leave-group-out (LGO) crossvalidation, and the Y-randomization test. This model, with high statistical significance (R2 train = 0.982, F = 388.715, Q2 LOO = 0.973, Q2 LGO = 0.977 and R2 test = 0.986) could predict the activity of the molecules with a percentage prediction error lower than 5 %.

Green benzylation of sodium salicylate by phase-transfer catalysis with third-liquid phase in a continuous two-phase-flow reactor

The synthesis of benzyl salicylate frequently used in cosmetics was investigated by third-liquid phase-transfer catalysis (TLPTC) in a continuous two-phase-flow reactor. This reactor was designed in a way to keep the third-liquid phase residing in the middle part with the aqueous and organic phases flowing through it countercurrently. To prevent the entrainment of the catalyst into outlet streams, two membranes were installed in the reactor with a lipophilic type in the upside and a hydrophilic one in the downside of the reaction zone. With 0.025 mol of tetrabutylphosphonium bromide, 0.125 mol of NaBr and 0.67 M of sodium salicylate in the aqueous phase to form the third-liquid phase, the yield of benzyl salicylate in the organic outlet was 82% at steady-state for the conditions of 0.33 M of benzyl bromide in n-heptane, space time at 290 min, stirring speed at 300 rpm and temperature at 70 °C. The effects of various operating parameters were explored and the distributions of the catalyst between phases after reaction were analyzed. A kinetic model concerning the two-phase flow was proposed to describe the overall reaction. The results show that the green benzylation of sodium salicylate by TLPTC in a continuous two-phase-flow reactor was developed.

Hydrogen Storage in Semiclathrate Hydrates of Tetrabutyl Ammonium Chloride and Tetrabutyl Phosphonium Bromide

Original calorimetric and phase equilibrium properties for hydrogen + tetrabutylammonium bromide (TBAB), tetrabutylammonium chloride (TBACl), or tetrabutylphosphonium bromide (TBPB) semiclathrate hydrates were measured using differential scanning calorimetry under pressure. The dissociation temperatures of H2 + TBACl and H2 + TBPB semiclathrate hydrates are very close to the ambient temperature at low pressures around 15.0 MPa. H2 + TBACl and H2 + TBPB systems therefore exhibit better and comparable stability than the H2 + TBAB system at equivalent pressure, respectively. The amount of hydrogen stored in H2 + TBACl and H2 + TBPB semiclathrate hydrates was estimated in terms of the H2-to-water mole ratio (nH2/nH2O) calculated from disssociation enthalpies and (p, T) equilibrium data. In terms of mass fraction deduced from the ratio (nH2/nH2O), H2 + TBACl and H2 + TBPB semiclathrate hydrates can store 0.12 % and 0.14 % of hydrogen, respectively. Moreover, the quantity of hydrogen stored in these two semiclathrate hydrates is significantly higher than that stored in the H2 + TBAB system.

Thermal cured epoxy resins using certain calixarenes and their esterified derivatives as curing agents

The acetyl esterified calixarene (CA) derivatives were prepared from calix[4]resorcinarene (CRA), and p-tert-butylcalixarene (BCA[n], n = 4, 6, 8), respectively. Using these CA derivatives as curing agents, the thermal curing reactions of two multifunctional epoxy resins (jER 828, 186 g/equiv., and ESCN, 193.7 g/equiv.) were investigated. The temperatures of glass transition (Tg) and decomposition (T) were measured by DSC and TGA, respectively. Based on the yields, Tgs, and Tds of the thermal cured jER 828 epoxy resin with CRA-E100, the curing conditions were optimized to be tetrabutylphosphonium bromide (TBPB) as catalyst in NMP at 160 °C for 15 h. Under this curing condition, the cured materials of jER 828 or ESCN using various CA derivatives as curing agents were prepared. Except for BCA4 derivatives, the yields of thermal curing reaction were higher than 90%. Tgs and Ts of the resultant cured materials were in the range of 113–248 °C and 363–404 °C, respectively. These results mean that the cured epoxy resins with excellent Tgs were successfully formed by using CA derivatives as curing agents. It was also found that the Tgs of cured epoxy resins were strongly affected by the degree of esterification of CA derivatives. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1931–1942, 2010

Apparent Molar Volume and Compressibility of Tetrabutylphosphonium Bromide in Various Solvents

The densities of tetra-n-butylphosphonium bromide in ethanol, 1-propanol, 1-butanol, acetone, and acetonitrile at (288.15, 293.15, 298.15, 303.15, 308.15, 313.15, and 323.15) K and sound velocities at 298.15 K have been measured. From these data, apparent molar volumes VΦ at (288.15, 293.15, 298.15, 303.15, 308.15, 313.15, and 323.15) K and the apparent molar isentropic compressibility KS,Φ at 298.15 K of tetrabutylphosphonium bromide in nonaqueous solvents have been determined.

Kinetics of the oxidation of 1-phenyl ethanols with phase-transferred monochromate in organic solvents

Kinetic studies on the oxidation of 1-phenyl ethanol and its para-methyl, para-methoxy and para chloro derivatives have been carried out using phase transferred chromate as oxidant in pure organic solvents. The inorganic oxidant was transferred to the non polar media using the phase transfer catalyst, tetrabutyl phosphonium bromide (TB PB). The electronic effects of the substituents, effect of varying the temperature on the rate, as well as the effect of varying the dielectric constant of the medium on the rate have been investigated. The rate data fitted well with the Hammett equation.