Ethyltriphenylphosphonium Bromide Research Articles

The protocatechuic acid-based deep eutectic solvent-mediated green synthesis of 1,2,4,5-tetrasubstituted imidazoles.

A novel protocatechuic acid-based deep eutectic solvent (ETPPBr/PCA-DES) was prepared by mixing ethyltriphenylphosphonium bromide (ETPPBr) and protocatechuic acid (PCA = 3,4-dihydroxybenzoic acid), and its structure was fully investigated by using the FT-IR, TGA/DTA, densitometer, eutectic point and 1H NMR techniques. Different molar ratios of ETPPBr to PCA were examined and the eutectic point phase diagram showed that the best ratio for the synthesis of the new DES is the one-to-one ratio of the two starting materials (ETPPBr and PCA). Then, the novel DES was used as a new and capable catalyst for the green synthesis of diverse 1,2,4,5-tetrasubstituted imidazoles a1-a12 from the four-component condensation reaction of phenanthrene-9,10-dione, aromatic amine, aromatic aldehyde, and ammonium acetate with high yields and very short reaction times. High yields and very short reaction times are two advantages of our proposed method compared with the previous reported methods.

The gentisic acid-based deep eutectic solvent mediated green synthesis of acridines

A novel gentisic acid-based deep eutectic solvent (ETPPBr/GA-DES) was prepared by mixing of ethyltriphenylphosphonium bromide (ETPPBr) and gentisic acid (GA = 2,5-dihydroxy-benzoic acid), and its structure fully investigated by using the FT-IR, TGA/DTA, densitometer and 1HNMR techniques. Different mole ration of ETPPBr to GA were examined and the eutectic point phase diagram showed that the best ratio for the synthesis of a novel gentisic acid-based DES is the one-to-one mole ratio of the two starting materials (ETPPBr and GA).Then, ETPPBr/GA-DES was used as a novel and capable catalyst for the green synthesis of diverse N-substituted decahydroacridine-1,8-diones a(1−12) from the three-component condensation reaction of aromatic aldehyde, aromatic amine and dimedone in solvent-free conditions at 80 °C.

Application of a novel deep eutectic solvent as a capable and new catalyst for the synthesis of tetrahydropyridines and 1,3-thiazolidin-4-ones

A novel deep eutectic solvent (ETPP-Br/THF-TCA-DES) was prepared by a mixture of ethyl triphenylphosphonium bromide (ETPP-Br) and tetrahydrofuran-2,3,4,5-tetra-carboxylic acid (THF-TCA, mole ratio 7:3), characterized by FT-IR, TGA/DTA, densitometer, eutectic point, and 1H NMR techniques and used as a capable and new catalyst for the synthesis of two sets of compounds: (1) the four new [a(1–4)] and the eleven [a(5–15)] known alkyl 1,2,6-trisubstituted-4-[(hetero)arylamino]-1,2,5,6-tetrahydropyridine-3-carboxylates and (2) the two new [b(1–2)] and the eight [b(3–10)] known 1,3-thiazolidin-4-ones in DES with short reaction time, high yields, and easy recycling and separation of the DES catalyst. There is a nice consistency between the proposed structure of the DES compound, the integration values of the 1H NMR peaks and the ratio of ETPP-Br to THF-TCA obtained from the eutectic point phase diagram. Also, the decrease in splitting patterns of the peaks in DES, compared to the two starting materials can be the good evidence of the hydrogen bond formation between the two components.

Experimental and theoretical investigations of Ethyltriphenylphosphonium bromide dihydrate crystal for optical applications

The organic Ethyltriphenylphosphonium bromide dihydrate (ETPBD) single crystal is grown by slow evaporation method at room temperature. The unit cell parameters and crystal system were obtained by the single crystal X-ray diffraction technique. The optical parameters and absorption wavelength assessment are made by UV–Visible spectroscopic technique. The second harmonic generated efficiency is evaluated by using the Kurtz-Perry technique. The polarizability value, charge distribution, HOMO-LUMO energy, natural bond orbital and thermodynamical properties of the ETPBD crystal are estimated from the quantum chemical calculation with the help of DFT. The intermolecular interaction of ETPBD crystal is also analyzed by Hirshfeld surface analysis. The various functional groups were analyzed by spectroscopic studies of FTIR and FTRAMAN by experimentally identified functional groups that were compared with theoretically computed values.

Zero‐Dimensional Luminescent Metal Halide Hybrids Enabling Bulk Transparent Medium as Large‐Area X‐Ray Scintillators

AbstractScintillators are critical in medical imaging, non‐destructive security screening, and space exploration applications. However, it still remains a challenge to achieve large‐area and high‐transparency scintillators by a low‐cost and easy‐to‐implement way. Herein, a large transparent medium with a diameter over 10 cm is prepared via a facile melt‐quenching strategy using a stoichiometric mixture of ethyltriphenylphosphonium bromide (ETPBr) and MnBr2 as raw materials. Benefiting from the crystallization behavior of high‐efficiency green‐emitting (ETP)2MnBr4 nanocrystals hybridized with amorphous phase in the transparent wafer, the (ETP)2MnBr4‐based transparent medium as a scintillator evidences a high transparency (over 80%, ranging from 500 to 800 nm), a high light yield of ≈35 000 ± 2000 photon per MeV, a low detection limit of 103 nGy S–1, and a competitive spatial resolution of 13.4 lp mm–1 for X‐ray imaging. This work offers a distinctive simple and fast melt‐quenching methodology to fabricate (ETP)2MnBr4 metal halide X‐ray scintillator wafer with large‐area and shape flexibility, excellent transparency, and high scintillation performance for the medical or industrial X‐ray imaging application.

Highly efficient and reversible low-concentration SO2 absorption in flue gas using novel phosphonium-based deep eutectic solvents with different substituents

Four hydrogen bond acceptors (HBAs) with different carbon chain length substituents, including methyl-triphenyl phosphonium bromide (MTPB), ethyl-triphenyl phosphonium bromide (ETPB), propyl-triphenyl phosphonium bromide (PTPB), and butyl-triphenyl phosphonium bromide (BTPB), combined with ethylene glycol (EG) were developed to synthesize four low-viscosity deep eutectic solvents (DESs). In this study, the effect of different substituents in DESs on low-concentration SO2 absorption was systematically studied at 30–70 °C. Experimental results show that the EG-MTPB DES has a higher SO2 absorption capacity and a lower viscosity than other DESs. The reason for the higher SO2 absorption capacity of EG-MTPB DES was described by viscosity experiments and quantum chemical calculations. It was shown that the strong polarization ability of the CH3 group promotes the absorption of SO2 by DESs. 1H NMR and FTIR results indicated that chemical interactions primarily exist between the S of SO2 and Br, and the O of SO2 and the H atom of EG form hydrogen bonds. The density functional theory (DFT) results also confirm that the charge of the Br atom migrated to the S atom. Also, thermostability and regeneration experiments showed that the EG-MTPB DES exhibits good stability and can thus be used for industrial flue gas desulfurization.

High CO2 absorption in new amine based-transition-temperature mixtures (deep eutectic analogues) and reporting thermal stability, viscosity and surface tension: Response surface methodology (RSM)

To study CO2 capture potential, three types of transition-temperature mixtures (TTMs) were prepared by mixing ethyltriphenylphosphonium bromide (MTPPB) as a hydrogen bond acceptor (HBA) and n-methyl diethanolamine (MDEA) as a hydrogen bond donor (HBD) in different molar ratios (1:7, 1:10 and 1:16). Fourier transform infrared spectroscopy (FT-IR) results showed that TTMs have almost similar spectra to their HBD (MDEA) with different levels of transmittance and exhibit similar behavior. From the experimental results, it was found that the thermal stability, viscosity and surface tension of TTMs decreased as the concentration of MDEA in the mixture increased. According to response surface methodology (RSM) models and analysis of variance (ANOVA), temperature and molar ratio had a great effect on the viscosity and surface tension of TTMs. Finally, it was found that CO2 solubility in TTMs (at 303.15 K at pressure up to 1.35 MPa) was enhanced as the MDEA quantity increased in the mixture up to 1:10 mol ratio. However, by increasing MDEA concentration to 16:1 mol ratio, there was a decreasing trend in the CO2 solubility data. Also, all TTMs, particularly TTM containing 10:1 mol MDEA (MTPPB-MDEA 1:10) exhibited an equilibrium loading capacity approaching 1 mol CO2 per mole solvent at high pressure, revealing their high potential for CO2 capture. A comparison showed that the CO2 solubility in the studied solvents was higher than that of existing deep eutectic solvents (DESs) and other TTMs as well as several ionic liquids (ILs) to date. To the best of our knowledge, this is the first study to report the CO2 solubility in phosphonium-base TTMs containing MDEA.

Synthesis of 3β-tert-Butyldimethylsiloxy-22-phenylthio-23,24-bisnorchola-5,9(11)-diene and Reductive Nucleophilic Attack on a Branched Aliphatic Aldehyde.

3β-tert-Butyldimethylsiloxy-22-phenylthio-23,24-bisnorchola-5,9(11)-diene, which has a double bond between C-9 and C-11 and a phenylsulfenyl group on the terminus of the side chain, is a potential synthetic intermediate for steroids with 9,11-unsaturation or 9,11-seco skeletons. We describe here the synthesis of the title compound from 17-ethylenedioxy-3-acetoxyandrosta-3,5-dien-11-one. The introduction of an ethylene unit to 3β-tert-butyldimethylsiloxyandrosta-5,9(11)-dien-17-one by the action of ethyltriphenylphosphonium bromide under basic conditions resulted in an inseparable mixture of two stereoisomeric products (5 : 1). However, in the subsequent step, only the (Z)-isomer was susceptible to the Lewis acid-catalyzed ene reaction with formaldehyde, giving a stereochemically pure product with the desired configuration. Within three steps, the ene-product was derivatized to the title compound, with a total yield of 53% over seven steps. Reductive terminal anion formation by treatment with lithium di-tert-butylbiphenyl (LiDBB) and subsequent nucleophilic attack on a branched aliphatic aldehyde was demonstrated, with an eye toward the introduction of side chains, especially for steroids with oxygen functionality at C-23.

Reactive plasticization of poly(lactide) with epoxy functionalized cardanol

New biobased plasticizers made of di‐functional glycidyl ether epoxy cardanol (ECard) were investigated to improve the ductility of renewable poly(lactide) (PLA). Compatibility between PLA and ECard was achieved out through in situ reactive grafting strategy catalyzed with Ethyltriphenyl phosphonium bromide (ETPB) using twin‐screw extruder. In absence of catalyst, ECard forms domain ill‐dispersed in the PLA matrix due to the high incompatibility between both phases. When ETPB is added as catalyst domain size distribution of the plasticizer decreased, indicating an enhanced compatibility due to the reactive grafting of a fraction of ECard plasticizer onto PLA backbone. Although all plasticized PLA specimens exhibit lower glass transition temperature, lower elastic/tensile modulus, lower yield stress, and higher strain at break, the reactive blend containing the lowest amount of catalyst, that is, 0.02 phr, exhibited the highest ductility behavior. POLYM. ENG. SCI., 58:E64–E72, 2018. © 2017 Society of Plastics Engineers

Optimization of Ultrasound-Assisted Oxidation of Thiophene Using Phase Transfer Catalyst

Thiophene oxidation with hydrogen peroxide was studied with tetrabutylammonium bromide, phenyltrimethylammonium tribromide, ethyltriphenylphosphonium bromide, benzyltrimethylammonium tribromide, tetrapropylammonium bromide, tetrabutylammonium hydrogensulphate, and 18-crown-6-ether as phase transfer catalysts (PTC) under ultrasound. Highest conversion (82.59%) was achieved with benzyltrimethylammonium tribromide at 1,200 rpm and 30 kHz frequency. The effect of parameters such as oxidant-to-sulphur mole ratio, intensity of ultrasound, stirrer speed, catalyst amount, and operating temperature on oxidation was explored by using benzyltrimethylammonium tribromide. Central composite design was chosen for optimization of conversion using temperature, catalyst loading, and molar ratio. The pseudo first-order kinetics with apparent activation energy of 79.55 kJ/mol was established.

Solubility of sodium chloride in phosphonium-based deep eutectic solvents

The solubility of sodium chloride (NaCl) in several phosphonium-based deep eutectic solvents (DESs) is studied in this work. Seven combinations of DESs were investigated. The solubility of NaCl increased with temperature in all DESs at all combinations. The type of salt and hydrogen bond donor (HBD) and the salt:HBD mole ratio of the DES affected the solubility of NaCl. The solubility of NaCl in DESs that use ethylene glycol or glycerol (neutral molecules) as HBDs is very low in comparison to DESs that use zinc (II) chloride (ZnCl2) or ferric (III) chloride (FeCl3) which are metal halides as complexing agents. DESs containing ZnCl2 produced the highest solubility. Ethyltriphenylphosphonium bromide:ZnCl2 DES possessed a NaCl solubility of 88.500wt.% at 111°C, and tetrabutylphosphonium bromide:ZnCl2 DES possessed NaCl solubilities of 70.120wt.% and 75.000wt.% at 100°C and 160°C, respectively. The thermodynamic activity coefficient non-random two-liquid (NRTL) model was used to correlate the solubility of NaCl in the studied DESs. The calculated values in some DESs showed satisfactory agreement with the experimental values.

Growth, photoluminescence, thermal and mechanical behaviour of Ethyltriphenylphosphonium bromide dihydrate crystal

Single crystal of Ethyltriphenylphosphonium bromide dihydrate (ETPB) was grown by slow evaporation solution growth technique. The grown crystal was confirmed by single crystal X-ray diffraction. The functional groups and vibrational frequencies were identified using FT-IR and FT-Raman spectral analyses. Optical properties were studied by UV–Visible and photoluminescence spectroscopic techniques to explore its efficacy towards device fabrication. Thermal characteristics of ETPB were studied using the TGA/DTA and DSC response curves. The mechanical behaviour of the grown crystal was studied using Vicker’s microhardness tester and the work hardening coefficient was evaluated. The second harmonic generation of the title compound was tested by Kurtz–Perry powder technique.

Application of Tetraphenyl- and Ethyltriphenylphosphonium Salts for Separation of Reactive Dyes from Aqueous Solution

The decolorization efficiency of four anionic dyes dissolved in aqueous solution using two quaternary phosphonium salts, ethyltriphenylphosphonium bromide, and tetraphenylphosphonium bromide, has been investigated by spectroscopic measurements in neutral, acidic and basic media. The NMR studies suggest possible formation of ion pairs of tetrasubstituted phosphonium salts with the reactive dyes. According to the results, the tetraphenylphosphonium bromide, which contains a more hydrophobic and bulky cation, exhibited a stronger tendency to associate with the dyes.

Ethyltriphenylphosphonium bromide dihydrate

In the crystal structure of the title hydrated bromide salt, C20H20P+·Br−·2H2O, O—H⋯Br and O—H⋯O hydrogen bonds as well as C—H⋯Br contacts connect the different components into a three-dimensional network. In the cation, the aromatic rings make dihedral angles of 55.24 (5), 76.16 (4) and 85.68 (4)°.

Improvement in toughness of poly( l-lactide) (PLLA) through reactive blending with acrylonitrile–butadiene–styrene copolymer (ABS): Morphology and properties

Poly( l-lactide) (PLLA) was melt-blended with acrylonitrile–butadiene–styrene copolymer (ABS) with the aim of enhancing impact strength and elongation at break of PLLA, but not sacrificing its modulus and stiffness significantly. However, PLLA and ABS were found to be thermodynamically immiscible by simply melt blending and the formed blends show deteriorated mechanical properties. The reactive styrene/acrylonitrile/glycidyl methacrylate copolymer (SAN-GMA) by incorporating with ethyltriphenyl phosphonium bromide (ETPB) as the catalyst was used as the in situ compatibilizer for PLLA/ABS blends to improve the compatibility between PLLA and ABS. The reactive process during melt blending was investigated by Fourier transformed infra-red (FTIR). It showed that the epoxide group of SAN-GMA reacted with PLLA end groups under the mixing conditions and that the addition of ETPB accelerated the reaction. Phase structure and physical properties of the compatibilized blends were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), dynamic mechanical analysis (DMA), tensile tests and impact property measurements. It was found that the size of ABS domains in PLLA matrix is significantly decreased by addition of the reactive compatibilizer. The dynamic mechanical analysis revealed markedly shifted glass transition temperatures for both PLLA and ABS, indicating the improved compatibility between PLLA and ABS. The mechanical tests showed the compatibilized PLLA/ABS blends had a very nice stiffness-toughness balance, i.e., the improved impact strength and the elongation at break with a slightly loss in the modulus.

Direct Syntheses of Bis(tetraphenylphosphonium) and Bis(ethyltriphenylphosphonium) Hexabromo‐diselenates(II), [PPh4]2[Se2Br6] and [PEtPh3]2[Se2Br6]. The Crystal Structure of [PEtPh3]2[Se2Br6

AbstractBrown crystals of [PPh4]2[Se2Br6] (1) and [PEtPh3]2[Se2Br6] (2) were obtained when selenium and bromine reacted in acetonitrile solution in the presence of tetraphenylphosphonium bromide and ethyltriphenylphosphonium bromide, respectively. The crystal structure of 2 has been determined by X‐ray methods and refined to R = 0.0420 for 4161 reflections. The crystals are monoclinic, space group P21/n with Z = 2 and a = 13.055(3) Å, b = 12.628(3) Å, c = 13.530(3) Å, β = 92.40(3)° (293(2) K). In the solid state structure of 2 the dinuclear hexabromo‐diselenate(II) anion is centrosymmetric and consists of two distorted almost square‐planar SeBr4 units sharing a common edge through two bridging Br atoms. The terminal SeII–Br bond distances are found to be 2.419(1) and 2.445(1) Å, the bridging μBr–SeII bond distances 2.901(1) and 2.802(1) Å.

Synthetic approach to preparation of indole derivatives fused with a bicyclo[3.3.1]nonane framework

Starting with Δ15-17-ketosteroids, applying Normant reaction with allylmagnesium bromide and anionic Cope rearrangement of the formed allyl alcohol, 15α-derivatives of androstane series were prepared. The latter were brought into Wittig reaction with an ylide generated from ethyltriphenylphosphonium bromide, and the product was subjected to ene reaction to provide 15α-substituted pregnanes.

Rate intensive and selective etherification of vanillin with benzyl chloride under solid–liquid phase transfer catalysis by aqueous omega phase

The alkylation of vanillin, containing three reactive groups, with benzyl chloride is challenging and can lead to both C- and O-alkylated products, particularly when liquid–liquid (L–L) phase transfer catalysis (PTC) is used. In the current studies, solid–liquid (S–L) PTC has been employed in the reaction of solid sodium salt of vanillin and benzyl chloride in toluene at 90 °C to make 4-benzyloxy vanillin, an ether, which is used as a perfume and also as a starting material for the synthesis of thalifoline, ephedradine as alkaloids and in synthesis of flavonoid compounds. The selectivity towards the desired product under S–L PTC is 100%. The rates of reaction are enhanced greatly by using trace quantities of water (the so-called omega phase (ω)) with 100% selectivity to the ether. Efficacy of various phase transfer agents such as TBAB (tetra- n-butyl ammonium bromide), TBAHS (tetra- n-butyl ammonium hydrogen sulfate), TPAB (tetra- n-propyl ammonium bromide), TEAB (tetraethyl ammonium bromide) and ETPB (ethyl triphenyl phosphonium bromide) was evaluated under otherwise similar conditions at 90 °C and explained. The order of activity was as follows: TBAB (maximum) > TBHS > TPAB > TEAB > ETPB (minimum). A theoretical model is developed to account for the enhancements in rates of reaction and selectivity to the ether. The kinetic constants have been evaluated and the apparent activation energy is determined as 9.64 kcal/mol. The results are novel.

Commensurate and incommensurate structures of the hexabromotellurate(IV) bis[dibromodiselenate(I)] ion - [(C2H5)n(C6H5)4-nP]2[TeBr6(Se2Br2)2], n = 0,1.

Structure analysis of [(C(2)H(5))(n)(C(6)H(5))(4-n)P](2)[TeBr(6)(Se(2)Br(2))(2)] is presented for n = 1 and 0 [hereafter (I) and (II)]. Crystal (I) has been synthesized from elemental selenium, tellurium tetrabromide, ethyltriphenylphosphonium bromide and bromine. It has a standard monoclinic structure, space group P2(1)/c, and has been solved and refined to R = 0.0357 for 4803 observed X-ray reflections by traditional techniques. Crystal (II), which has been prepared from elemental selenium, tellurium tetrabromide, tetraphenylphosphonium bromide and bromine, is an incommensurately one-dimensionally modulated structure with planar monoclinic superspace group. (II) has been refined to R = 0.0501 for 4247 observed reflections. The modulation of the atoms that belong to the anion switches between two different basic positions, which are described by the crenel function algorithm. The modulation of the phenyl groups is much weaker and it could be refined within the rigid-body approximation. The TeBr(6) octahedron is nearly regular in both structures. The two Br atoms of the octahedron have a bond to one of the Se atoms in an Se(2)Br(2) molecule. For (I) both bonded Br atoms are trans positioned, while for (II) they can be either trans or cis positioned. The alternations of those arrangements are caused by modulation. The point group of the anion is -1 for crystal (I) and 2/m for the average structure of crystal (II).

In situ compatibilized SAN/LCP blends through reactive copolymers

AbstractStyrene–acrylonitrile–glycidyl methacrylate (SAG) copolymers with various contents of glycidyl methacrylate (GMA) were used to compatibilize the incompatible blends of styrene–acrylonitrile (SAN) and a liquid crystalline polymer (LCP). These SAG copolymers contain reactive glycidyl groups that are able to react with the carboxylic acid and/or hydroxyl end groups of the LCP to form the SAG‐g‐LCP copolymers during melt processing. The in situ–formed graft copolymers tend to reside along the interface to reduce the interfacial tension and to increase the interface adhesion. The morphologies of the SAN/LCP blends were examined by using scanning electron microscopy (SEM), where the compatibilized SAN/LCP blends were observed with greater numbers and finer fibrils than those of the corresponding uncompatibilized blends. The mechanical properties of the blends increased after compatibilization. The presence of a small amount (200 ppm) of ethyl triphenylphosphonium bromide (ETPB) catalyst further promotes the graft reaction and improves the compatibilization. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3321–3332, 2001