Phosphonium Type Research Articles

Development of palladium catalysts immobilized on supported phosphonium ionic liquid phases

The application of heterogeneous palladium catalysts supported on phosphonium ion modified silica was investigated in aminocarbonylation reactions of aryl iodides. In contrast to catalysts immobilized on supports decorated with imidazolium ions, the application of phosphonium type supported ionic liquid phases made it possible to carry out double carbonylation with good selectivity in apolar toluene which led to a considerable decrease in the amount of leached palladium. An even better stabilization of the palladium catalyst could be achieved by introducing dicationic organic moieties incorporating both imidazolium and phosphonium ions on the surface of the support. At the same time, the former catalyst, obtained from the supported phosphonium ionic liquid phase was found to be superior in monocarbonylations. The amide products were obtained in good yields by the proper choice of the reaction conditions, such as reaction temperature and pressure and that of the base.

The synergistic extraction by combined ammonium and phosphonium type ionic liquids for rare earth elements separation

A novel synergistic system of combined ammonium and phosphonium type ionic liquids is reported for the first time, which displays pronounced synergistic effect in the extraction of Lu(III). The synergistic enhancement coefficients from different mole fractions of [P66614][EHEHP] and [N1888][BTMPP] were calculated. Extraction mechanism of the combined functionalized ionic liquids for Lu(III) was shown to be ion association. Thermodynamic functions of the synergistic extraction system were obtained. The loaded Lu(III) in the synergistic system could be fully stripped using hydrochloric acid. The novel synergistic extraction provides the possibility of separating heavy lanthanides, which reveals theoretical and practical importance in REEs separation.

Redox Behavior of the Hexacyanoferrate Complex Immobilized into an Ionic Liquid-Modified Electrode By Using Seiras Measurement

Self-assembled monolayer (SAM) is a useful technique to modify a functional compound on a surface. However, the compounds modified on a surface often change their chemical properties. We have recently studied an ionic liquid (IL)-modified surface as a new technique to immobilize a functional compound on a substrate surface and as a material providing a novel reaction field on the surface, instead of the typical SAM method. IL is an ionic compound being in the liquid state at room temperature and a designable compound. Previously, we modified a bulky phosphonium-type IL onto a Au electrode, and succeeded in entrapping three types of metal complexes into the vacant space formed with the IL molecules without any chemical bindings, regardless of the net charges of the complexes.1) The immobilization of the complexes into the surfaces were confirmed with the electrochemical measurements, which indicated that the electrochemical properties of the complexes were similar to those in homogeneous condition. However, we did not have any structural information about the surfaces. In order to investigate the structure of the compounds modified on the surface, the surface enhanced infra-red absorption spectroscopy (SEIRAS) measurement was applied on the IL modified electrode. The SEIRAS provides an enhanced IR absorption intensity by 10-100 times stronger than that of IR-RAS measurement and simultaneous electrochemical information.2) Therefore it is expected that the redox behavior of the compound entrapped on the surface can be observed spectroscopically. In this report, we will discuss the immobilization of a hexacyanoferrate (Fe(CN)6]3−/4−) complex into the IL-modified electrode and the redox behavior by using a SEIRAS measurement. We prepared a chemical deposited Au thin film on a Si prism as a working electrode. According to our previous report,1) the phosphonium type IL with a disulfide group has been modified on the Au electrode (IL/Au). The [Fe(CN)6]3−/4− complex was immobilized into the IL/Au by using CV measurement in the complex solution (Fe@IL/Au). The SEIRAS measurement of the IL/Au has performed during the electrochemical measurement. The IR band intensity assignable to C≡N group in the complex was increased gradually during the immobilization. After the immobilization, the redox potential of the complex immobilized on the surface has been observed at 0.1 V vs. Ag/AgCl. This redox potential is almost equal to that in an aqueous solution. The SEIRAS measurement of Fe@IL/Au was also performed during the electrochemical measurement. These results indicate that the environment of C≡N groups in Fe@IL/Au are different from the homogeneous conditions, suggesting that the coordinated C≡N groups statically interact to the cation parts of IL modified on the surface. 1) T. Kitagawa et al., Chem. Commun., 2013, 49, 10184-10186. 2) M. Osawa, et al., Appl. Spectroscopy., 1993, 47, 1497-1502. This study was supported by the Cooperative Research Program of Catalysis Research Center, Hokkaido University. Figure 1

Immobilization of a Cobalt(III) Complex Possessing Selective Nitric Oxide Capturing Ability onto an Ionic Liquid-modified Au Electrode: Reactivity of the Electrode toward Nitric Oxide

A Co(III) complex possessing selective nitric oxide (NO) capturing ability was immobilized onto a bulky phosphonium type ionic liquid-modified Au electrode, IL/Au, (Co@IL/Au), which was confirmed b...

Reversed micelle synergistic extraction from phosphonium ionic liquid extractants in diluent for rare earth

The first synergistic extraction between quaternary phosphonium type ionic liquid extractants in toluene for rare earth was reported in this article. There were two different ion‐association mechanisms in the synergistic extraction system. The formed reversed micelles contributed to increase extractability of the synergistic extraction system to a considerable extent. On the one hand, million tons of saponification wastewater from acidic extractants may be avoided by developing the extraction system using bifunctional ionic liquid extractants. On the other hand, the novel synergistic extraction offers an effective strategy to increase the extractabilities of industrial extractants. This article reveals sustainable and efficient potentials for industrial rare earth separation. © 2016 American Institute of Chemical Engineers AIChE J, 62: 2163–2169, 2016

Microwave assisted enzymatic esterification of lactic acid and ethanol in phosphonium type ionic liquids as co-solvents

Microwave heating was found to have a beneficial effect on the enzymatic esterification of lactic acid (LA) with ethanol in Cyphos 202 ionic liquid (IL) medium. Microwave irradiation caused hydrolysis of lactoyllactic acid (the linear dimer of LA) during the reaction, thus, as a result, more lactic acid was available as substrate and a higher ester yield was achieved in the esterification.

Enzymatic Esterification of Lactic Acid under Microwave Conditions in Ionic Liquids

Ethyl lactate is a natural flavouring compound and can be used as an environmentally friendly solvent, as well. Lactic acid production requires costly downstream processes, which increases the price of the products. One of the latest purification methods is the extraction of the lactic acid from the fermentation broth by phosphonium type ionic liquids. This method gives the possibility to synthetise lactates in the extracting agent avoiding an expensive separation process. Microwave heating is widely used in organic chemistry because it usually shortens the reaction time and enhances the reaction rate, but its effect on enzymatic esterification reactions in ionic liquid media was hardly investigated. For comparison of the ethyl lactate synthesis in different media two organic solvents and 20 ionic liquids were tested. Eight suitable media were found: toluene and 7 ionic liquids. The reaction conditions of the enzymatic synthesis were optimised in toluene and in Cyphos 104. Using toluene the highest yield (80%) was achieved in a reaction mixture consisting of 1 mmol lactic acid, 5 mmol ethanol and 4.5 w/w% initial water content diluted by organic solvent to 5 cm3. The enzyme amount needed was 250 mg. In Cyphos 104 medium 0.8 mmol ionic liquid, 2 mmol lactic acid, 7 times ethanol excess, 2 w% initial water content and 25 mg immobilised Candida antarctica lipase B was enough to carry out the reaction up to 95% yield in 24 hour on 40 °C. The obtained yields and reaction parameters were compared using the two previous media and enzyme reusability tests were done. This experiment gave the result that smaller enzyme amount is enough in ionic liquid than in toluene and the enzyme stability is also much better in it. The synthesis was studied under microwave conditions as well, and the following effects were observed: The optimal initial water content was shifted from 3.7 w/w% to 3 w/w% but the same yield was achieved. Microwave heating accelerated the hydrolysis of lactoyllactic acid providing the mixture with fresh lactic acid and enhancing the reaction rate.

Electrochemical behaviors of multivalent complexes in room temperature ionic liquids based on quaternary phosphonium cations

A new group of room temperature ionic liquids based on triethylalkyl and tri- n-butylalkylphosphonium cations with a bis(trifluoromethylsulfonyl)imide anion as a novel green solvent is presented. The electrochemical behaviors of trivalent, divalent and neutral complexes such as rare earth, noble metal and ferrocene were investigated in phosphonium based ionic liquids in comparison with the corresponding ammonium type of ionic liquids. The diffusion coefficients of these metal complexes were estimated by cyclic voltammetry, chronoamperometry and chronopotentiometry, because it is important for development of the electrochemical devices to understand the available diffusive properties. The redox potentials of these trivalent lanthanide couples suggested that the donor property of phosphonium based ionic liquids was slightly larger than that of nitrogen based ionic liquids. The palladium complexes were more stabilized in phosphonium ionic liquids due to the relatively strong ligand field. The redox reaction of neutral complex, ferrocene, was reversible electrochemically in triethylalkyl and tri- n-butylalkyl phosphonium based ionic liquids. The multivalent and neutral complexes in phosphonium type of ionic liquids were somewhat movable than that in corresponding ammonium ionic liquids because the interaction between the cation and the anion in phosphonium based ionic liquids is weaker.

A Bicyclic P–P‐Bridged 1,3,2,4‐Diphosphadiboretane Cation and an Imino(phosphinidene)borane–AlBr3 Adduct

AbstractDepending on reaction conditions the 1,3,2,4‐diphosphadiboretane 1 reacts with AlBr3 to give the unstable adduct tmp=B=P(tBu)AlBr3, 3, and/or the somewhat more stable salt [(tmpB)2(PtBu)P]+[AlBr4], 2. The X‐ray structure determination of 3 shows an almost linear NBP array with BN and BP double bonds resembling an allene type structure. NBO analysis shows the presence of BN‐ and BP‐π‐bonds. On the other hand, the cation of compound 2 has a bicyclic structure with a long P–P bond [2.349(2) Å]. The B–P bonds to the phosphonium type P2 atom [av. 1.939(5) Å] are longer than those to the tri‐coordinated P1 atom [1.889(6) Å]. NBO analysis of the model compound (H2NB)2(PMe)P+, 9, show that the P–P bond in 2 is formed from p‐orbitals.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)

Studies on response characteristics of drug ion-selective electrodes (II)--sulpha-drug sensitive electrodes using quaternary phosphonium and arsonium compounds.

Ion-pair complexes of sulphonamide derivatives with quaternary phosphonium and quaternary arsonium have been synthesized and their electrode performances studied. It has been found that the electrode functions depend mainly on the site cation rather than on the anionic species and deteriorate in the order of cetyltrioctylammonium greater than cetyltriphenylphosphonium greater than cetyltriphenylarsonium. The electrode selectivity for different sulpha-drugs decreases in the order of sulphathiazole greater than sulphamethoxazole greater than sulphadimethoxine, sulphadoxine greater than sulphacetamide greater than sulphadiazine greater than sulphanilamide. Selectivity coefficients depend not only on the molecular connectivity index chi, but also on the electronic charge at the ionizing amide nitrogen atom sigma and pKa according to the following formula: logKij = a chi + b sigma - CpKa - d. The quaternary phosphonium type electrodes have been suggested for use in the potentiometric determinations of sulpha-drugs.

Utilisation d'ylides du phosphore en chimie des sucres : VIII. Actions comparées de divers types d'ylides sur un hexopyranoside-4-ulose

When methyl 2,3- O-isopropylidene-6- O-methyl-α- D- lyxo-hexopyranosid-4-ulose is treated with various phosphorus ylides of the phosphonium type, branched unsaturated sugars are obtained in yields ranging from 0 to 80%. The reaction takes place with partial inversion of configuration at C-5, the extent of which varies between 2 and 67%. The attribution of the configurations at C-5 and C-4 is discussed, as well as the interest presented by the study of this inversion for the understanding of the mechanism of the Wittig reaction.

SPECTROSCOPIC STUDIES OF ORGANOPHOSPHORUS COMPOUNDS: PART I. THE CONSTITUTION OF ALKYLPHOSPHINE – CARBON DISULFIDE ADDUCTS

The constitution of the alkylphosphine – carbon disulfide adducts has been investigated by the study of their infrared spectra. Certain definite features of the spectra of the adducts are the shift of the P—C asymmetric vibrations to higher frequencies and the large shifts in the fundamentals of the acceptor molecule. These features are attributed to the formation of a quadruply connected phosphorus compound. From a comparison of the spectra of the carbon disulfide adducts with those of the corresponding phosphonium compounds, phosphine oxides and phosphines, evidence is provided for the structure of these compounds which has been suggested to be of the phosphonium type.