Cesium Salts Research Articles

Lithium-Mediated Ammonia Electro-Synthesis: Effect of CsClO4 on Lithium Plating Efficiency and Ammonia Synthesis

Electro-reduction of nitrogen aided by lithium offers a new route for ammonia synthesis. In this novel approach, the first step of lithium plating plays a determining role in faradaic efficiency (FE) of the electro-synthesis process. It was found that the simple addition of cesium salt in a conventional organic electrolyte enhanced Li plating performance (FE of 82.3% for ammonia synthesis) to a substantial extent. This improvement appeared to have a lot to do with a Cs-caused change in morphology of Li deposit, which brought about the suppression of parasitic side reactions between metallic Li and propylene carbonate. This study proves that FE enhancement can be made possible via a simple change in electrolyte composition, an approach that is collectively called electrolyte engineering, and this approach can serve as effective means for making the best of Li-mediated ammonia synthesis.

Carbonylation of Dimethyl Ether on Ag/ Cs1.5H1.5PW12O40: In-Situ FTIR Spectroscopy Study of the Ag-Carbonyls

AbstractHalide-free carbonylation of dimethyl ether (DME) to methyl acetate over heterogeneous catalysts offers a potentially green route to the production of important industrial chemicals. Previously we have shown that the addition of 1% of silver to Cs1.5H1.5PW12O40led to an increase in activity by a factor of two. Formation of silver carbonyl clusters on the surface of the catalyst was demonstrated by in situ FTIR spectroscopy. The v(CO) of silver carbonyl was observed at 2188 cm-1 and may be explained by the formation of cationic silver carbonyl Ag(CO)+on the surface of the acidic cesium salt of 12-tungstophosphoric acid. In view of the increased efficiency, the novel bifunctional catalyst Ag/ Cs1.5H1.5PW12O40is expected to hold significant promise for practical use in new processes of basic organic chemistry.

Atom economical benzylation of phenol with benzyl alcohol using 20 % (w/w)Cs2.5H0.5PW12O40 supported on mesocellular foam silica (MCF) and its kinetics

Traditionally benzylation of phenol is carried out with benzyl chloride which is corrosive and difficult to handle, and the resultant reaction is not atom economical. Benzyl alcohol is an alternative to benzyl chloride which is safe and easy to handle. Benzyl phenols are industrially important products particularly in plastic, rubber and petroleum industries. In present study, cesium salt of dodecatungstophosphoric acid (Cs2.5H0.5PW12O40, Cs-DTP) supported on mesocellular foam (MCF) silica was used as catalyst among others. The activity of prepared catalyst, 20% (w/w) Cs-DTP/MCF was compared with Amberlyst-15, montmorillonite clay K10, S-ZrO2 and unsupported Cs-DTP catalyst. The supported catalyst showed better performance because of even distribution of acidic sites on MCF. The effect of reaction parameters were studied in detail and it was found that reaction follows second order kinetics. The activation energy was found to be 15.94 kcal/mol. The catalyst was found reusable.

Caesium Salt of Tungstophosphoric Acid Supported on Mesoporous SBA-15 Catalyst for Selective Esterification of Lauric Acid with Glycerol to Monolaurin

$$\hbox {Cs}_{2.5}\hbox {H}_{0.5}\hbox {PW}_{12}\hbox {O}_{40}$$ supported on SBA-15 catalysts were prepared via two-sequential-step post-impregnation method with different ratios of cesium salt. The synthesized catalysts were then characterized using nitrogen adsorption–desorption, FTIR, EDX, SEM, BET and TGA analyses in order to determine the physicochemical properties of the catalysts. The activity of the catalysts in the esterification of glycerol to monolaurin was investigated under various reaction parameters including catalyst loadings, reaction temperatures and glycerol-to-lauric acid molar ratio. The highest lauric acid conversion (71.8%) with 44.9% of monolaurin yield was obtained using 20 wt%Cs-HPW/SBA-15 catalyst in 4 h at 170 $${^{\circ }}\hbox {C}$$ using 4:1 of glycerol-to-lauric acid molar ratio and 2.5 wt% of catalyst loading. This catalyst was stable and reusable for up to three cycles in the esterification reaction without significant loss in catalytic activity.

Hydrocracking of Fischer‐Tropsch Wax with Tungstovanadophosphoric Salts as Catalysts

AbstractThe synthesis of liquid hydrocarbons from CO2 and H2, based on renewable energy and H2O electrolysis, respectively, in a power‐to‐liquid process is a promising concept for the substitution of fossil fuels. Such a process is based on Fischer‐Tropsch synthesis followed by hydrocracking to convert waxy products into transportation fuels such as gasoline and diesel oil. Heteropolyacid cesium salts as catalysts show appropriate activity for hydrocracking, and the selectivity in cracking model hydrocarbons and Fischer‐Tropsch wax can be tuned by the vanadium content of the catalyst. Thermal stability and surface properties were investigated, and the catalysts are compared with a classical H‐Y‐type zeolite used for hydrocracking.

Kinetic and mechanistic study of triose sugar conversion on Lewis and Brønsted acid solids

The effect of catalyst acid site nature on the reaction kinetics of the liquid-phase conversion of dihydroxyacetone with ethanol was investigated using Brønsted and Lewis acid solids. The reaction proceeds through a complex reaction network involving a sequence of consecutive and parallel reaction steps. Main final products were ethyl lactate and pyruvic aldehyde diethyl acetal. Different catalysts such as the cesium salt of tungstophosphoric acid (Cs-HPA), Amberlyst resin and alumina-supported tin and zinc oxides were used. Catalysts were characterized by ICP, X-ray diffraction, N2 physisorption, TPD of NH3 and FTIR of adsorbed pyridine. Cs-HPA contains only Brønsted acid sites and alumina-supported tin and zinc samples show exclusively Lewis acidity. During dihydroxyacetone conversion, the selectivities to the final products strongly depend on the nature of the surface acid sites present on the solids. Brønsted acid solids favor the synthesis of pyruvic aldehyde diethyl acetal with final yields of up to 93%, whereas the ethyl lactate is the main product on Lewis acid solids, reaching final yields of about 51%. A kinetic model based on a pseudohomogeneous mechanism was proposed to interpret the experimental catalytic data. The comparison of the kinetic rate constants obtained on both kinds of acid solids confirms that on Brønsted catalysts the route toward pyruvic aldehyde diethyl acetal is clearly favored. On Lewis solids, the synthesis of ethyl lactate occurs selectively via isomerization of the pyruvic aldehyde hemiacetal intermediate.

Classical problem of determination of limiting conductances of acetate anion revisited

Precise electrical conductivities of dilute aqueous solutions of acetic acid and its lithium, sodium, potassium and cesium salts were determined from 278.15K to 313.15K. Conductivities of alkali metal acetates from the literature and measured here were discussed in the framework of dissociation and hydrolysis model. This was performed by using the Quint-Viallard conductivity equations for 1:1 type electrolytes and the Debye-Hückel expression for activity coefficients. Excellent agreement between experimental and calculated conductances permitted to evaluate over the investigated temperature range, a consistent and reliable set of the limiting conductances of acetate anion, their diffusion coefficients at infinite dilution and the Stokes radius. Without using additional parameters, the classical problem of representation of acetic acid conductivities in dilute solutions was reexamined and solved, indicating internal consistency of applied molecular models.

STRUCTURE OF NEAREST ENVIRONMENT OF IONS IN AQUEOUS CESIUM IODIDE SOLUTIONS FROM X-RAY DIFFRACTION DATA

Comparatively large amount of works has been devoted to the investigation of the nearest environment of cesium ions in aqueous solutions. But up to date there are no precise quantitative parameters of it. Information about influence of concentration on cesium salts solutions structure is also absent. In order to get the coordination number of Cs+ ion and its dependence on the amount of dissolved salt the set of aqueous solutions of cesium iodide have been studied by X-ray diffraction method in wide concentration range under ambient conditions. Radial distribution functions (RDFs) of the solutions investigated have been calculated from experimental intensity curves of X-ray scattering. Interpretation of experimental peaks on RDFs has been made. On the basis of experimental results and literature information some physically reasonable models of solution have been constructed. Theoretical RDFs have been calculated for every model. Then an optimization procedure has also been made. On the ground of the best fitness between experimental and theoretical RDFs the optimal models for every solution have been found. All quantitative parameters have been tabulated and analyzed. Hydration numbers of Cs+ and I- increase with dilution, reaching in the solution of molar ratio 1:80 values 6.3 and 4.1, respectively. Interparticle distances of Cs+–ОН2 and I- –ОН2 are equal approximately to 0.312 and 0.359 nm. The ions do not form the second coordination shells. It has been determined that contact ion pairs Cs+–I- exist in whole concentration range investigated.Forcitation:Smirnov P.R., Grechin O.V., Voevodina E.A. Structure of nearest environment of ions in aqueous cesium iodide solutions from X-ray diffraction data. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2017. V. 60. N 7. P. 21-26.

Recognition and Extraction of Cesium Hydroxide and Carbonate by Using a Neutral Multitopic Ion-Pair Receptor.

Current approaches to lowering the pH of basic media rely on the addition of a proton source. An alternative approach is described herein that involves the liquid-liquid extraction-based removal of cesium salts, specifically CsOH and Cs2 CO3 , from highly basic media. A multitopic ion-pair receptor (2) is used that can recognize and extract the hydroxide and carbonate anions as their cesium salts, as confirmed by 1 H NMR spectroscopic titrations, ICP-MS, single-crystal structural analyses, and theoretical calculations. A sharp increase in the pH and cesium concentrations in the receiving phase is observed when receptor 2 is employed as a carrier in U-tube experiments involving the transport of CsOH through an intervening chloroform layer. The pH of the source phase likewise decreases.

Recognition and Extraction of Cesium Hydroxide and Carbonate by Using a Neutral Multitopic Ion‐Pair Receptor

AbstractCurrent approaches to lowering the pH of basic media rely on the addition of a proton source. An alternative approach is described herein that involves the liquid–liquid extraction‐based removal of cesium salts, specifically CsOH and Cs2CO3, from highly basic media. A multitopic ion‐pair receptor (2) is used that can recognize and extract the hydroxide and carbonate anions as their cesium salts, as confirmed by 1H NMR spectroscopic titrations, ICP‐MS, single‐crystal structural analyses, and theoretical calculations. A sharp increase in the pH and cesium concentrations in the receiving phase is observed when receptor 2 is employed as a carrier in U‐tube experiments involving the transport of CsOH through an intervening chloroform layer. The pH of the source phase likewise decreases.

An Anionic Surfactant on an Anionic Substrate: Monovalent Cation Binding.

Neutron reflectometry has been used to study the adsorption of the anionic surfactant bis(2-ethylhexyl) sulfosuccinate cesium salt on the anionic surface of mica. Evidence of significant adsorption is reported. The adsorption is reversible and changes little with pH. This unexpected adsorption behavior of an anionic molecule on an anionic surface is discussed in terms of recent models for surfactant adsorption such as cation bridging, where adsorption has been reported with the divalent ion calcium but not previously observed with monovalent ions.

Catalysis of Trans-esterification Reactions in Model Ester Mixtures

<p>Model trans-esterification reaction of n-butylbenzoate with phenyl-p-chlorobenzoate in the molar ratio of 20:1 has been studied. In order to evaluate catalysts based on lanthanide system the activity of nyodymium compounds – neodymium acetate, neodymium acetylacetonate and nitrate complex with benzo-12-crown-4 (neodymium nitrate coronate) – has been studied in the model trans-esterification reaction of n-butylbenzoate with phenyl-pchlorobenzoate. The effect of the electronic structure of the metal on the catalytic activity of the coronates of lanthanum, cerium, praseodymium, neodymium, samarium, terbium and erbium nitrates has been studied. In order to estimate the optimum concentration of the catalysts, a study of the dependence of the transesterification reaction on concentration of neodymium nitrate coronate was carried out. An asymptotic nature of the concentration dependence on the catalytic activity of lanthanide compounds has been observed. In order to look for new classes of inhibitors of trans-esterefication reaction, the model trans-esterificatiom reaction of n-butylbenzoate with phenyl-p-chlorbenzoate has been studied in the presence of some carborane derivatives: cesium salts of bis-1,2-(dicarbollyl) complexes of iron, cobalt and nickel(3+) and bis-1,2(dicarbollyl) nickel(4+) [(C<sub>2</sub>B<sub>9</sub>H<sub>11</sub>)2Me]. Some of these compounds were found to be effective inhibitors. The dependence of the constant rate of the model trans-esterification reaction of n-butylbenzoate with phenyl-p-chlorobenzoate on the concentration of cerium salt of bis-1,2-(dicarbollyl) complex of nickel has been studied to determine the optimum concentration of inhibitors. The influence of the ester chemical structure on the activity of ester groups in the trans-esterification activity has been determined in the reaction of di-n-butylterephthalate with different p-substituted derivatives of phenylbenzoate (phenyl-p-methoxybenzoate, phenyl-p-methylbenzoate, phenylbenzoate, phenyl-pchlorobenzoate, phenyl-p-nitrobenzoate, p-methoxyphenylbenzoate, p-methylphenylbenzoate, p-chlorophenylbenzoate, p-nitrophenylbenzoate, n-butylbenzoate, di-n-butylterephthalate) in presence of the samarium nitrate coronate.</p>

(N,Se) and (Se,N,Se) Ligands Based on Carborane and Pyridine Fragments – Reactivity of 2,6‐[(1′‐Me‐1′,2′‐closo‐C2B10H10)SeCH2]2C5H3N towards Copper and Silver

Two new closo‐carborane selenolated ligands, 2‐[(1′‐Me‐1′,2′‐closo‐C2B10H10)SeCH2]C5H4N (L1) and 2,6‐[(1′‐Me‐1′,2′‐closo‐C2B10H10)SeCH2]2C5H3N (L2), were prepared by the C–H activation of 1‐Me‐1,2‐C2B10H11 with nBuLi, followed by the insertion of elemental selenium into the C–Li bond and reaction with 2‐(BrCH2)C5H4N or 2,6‐(BrCH2)2C5H3N, respectively. The closo species L1 and L2 were deboronated with CsF to give the nido‐carborane cesium salts Cs[2‐{(1′‐Me‐1′,2′‐nido‐C2B9H9)SeCH2}C5H4N] (1) and Cs2[2,6‐{(1′‐Me‐1′,2′‐nido‐C2B9H9)SeCH2}2C5H3N] (2). The isolation of the complexes [Ag(OTf)(L2)] (3, OTf = triflate), [Ag(PPh3)(L2)][OTf] (4), [Cu(L2)(MeCN)][PF6] (5), and [Cu(L2)2][PF6] (6) indicates the coordination ability of L2 towards these metals. The molecular structures of L1 and L2 were established by single‐crystal X‐ray diffraction. Quantum‐chemical calculations confirmed the molecular geometries and also the presence of C–H···Se intramolecular interactions as well as C–H···H–B and B–H···π intermolecular interactions.

Nano-12-Tungstophosporic Acid Cesium Salt Synthesized by Ultrasound as Catalyst for Alkylation of Benzene with dec-1-ene

Abstract Nano 12-tungtophosphoric acid cesium salt (Cs-TPA) was synthesized under ultrasonic irradiation in nanoscale. The obtained catalyst was characterized by various methods. These analyzes indicate that the chemical structure and crystallinity of nano Cs-TPA remained unchanged while its morphology was found to be different from traditional Cs-TPA which is in irregular shape, becoming spherical with an average particle size of about 50 nm. Nano Cs-TPA was examined in the alkylation of benzene with dec-1-ene, its catalytic activity was remarkably enhanced compared to its original state. The catalyst reusability experiment also showed that the activity of nano Cs-TPA does not decrease even after five reused cycles.

Deep Oxidative Desulfurization of Refractory Sulfur Compounds with Cesium Salts of Mono-Substituted Phosphomolybdate as Efficient Catalyst

Catalytic oxidation desulfurization (ODS) of model oil containing refractory sulfur compounds, dibenzothiophene (DBT), benzothiophene (BT), and 4,6-dimethyldibenzothiophene (4,6-DMDBT), have been investigated with a series of cesium salts of the transition metal mono-substituted phosphomolybdates [PMo11M(H2O)O39]5− (M = Co2+, Ni2+, Zn2+, and Mn2+) as heterogeneous catalysts using H2O2 as the oxidant and acetonitrile as the extractant. The catalysts were characterized by Fourier transform infrared, DRS, scanning electron microscopy and X-ray diffraction. The main factors affecting the desulfurizing efficiency including catalyst dosage, and O/S (H2O2/DBT) molar ratio, temperature and reaction time were explored in detail. The results show that these catalysts are high efficient for sulfur removal of model oil under mild conditions, and CsPMo11Co is the most efficient with the sulfur-removal of 99.8, 92.9 and 85.3% for DBT, 4,6-DMDBT and BT, respectively at 60 °C for 100 min. Two probable reaction mechanisms was proposed for the oxidative desulfurization. Moreover, the catalysts could be recycled and maintained stability and high catalytic activity for consecutive desulfurization.

Thermochemical properties of U(VI) hybrid materials containing uranyl tetrachloride anions

The enthalpies of formation from simpler components of four hybrid materials bearing the [UO2Cl4]2− anion have been measured and compared to that of Cs2[(UO2)Cl4]. The hybrids contain protonated amines as charge balancing cations that form bifurcated H-bonding interactions with the chloro ligands of the anions. The structure of each material contains similar motifs and the driving force for the formation of the hybrids appears to be the enthalpy of organic cation formation (protonation). The hybrids are energetically much more stable than the corresponding cesium salt without a protonated organic cation.

π-electron S = ½ quantum spin-liquid state in an ionic polyaromatic hydrocarbon.

Molecular solids with cooperative electronic properties based purely on π electrons from carbon atoms offer a fertile ground in the search for exotic states of matter, including unconventional superconductivity and quantum magnetism. The field was ignited by reports of high-temperature superconductivity in materials obtained by the reaction of alkali metals with polyaromatic hydrocarbons, such as phenanthrene and picene, but the composition and structure of any compound in this family remained unknown. Here we isolate the binary caesium salts of phenanthrene, Cs(C14H10) and Cs2(C14H10), to show that they are multiorbital strongly correlated Mott insulators. Whereas Cs2(C14H10) is diamagnetic because of orbital polarization, Cs(C14H10) is a Heisenberg antiferromagnet with a gapped spin-liquid state that emerges from the coupled highly frustrated Δ-chain magnetic topology of the alternating-exchange spiral tubes of S = ½ (C14H10)•- radical anions. The absence of long-range magnetic order down to 1.8 K (T/J ≈ 0.02; J is the dominant exchange constant) renders the compound an excellent candidate for a spin-½ quantum-spin liquid (QSL) that arises purely from carbon π electrons.

Preparation of mesoporous Cs-POM@MOF-199@MCM-41 under two different synthetic methods for a highly oxidesulfurization of dibenzothiophene

Two different synthetic methods, the direct method and the substitution method, were used to synthesize the Cs-POM@MOF-199@MCM-41 (Cs-PMM), in which the modified heteropolyacid with cesium salt has been encapsulated into the pores with the mixture of MOF and MCM-41. The structural properties of the as-prepared catalysts were characterized using various analytical techniques: powder X-ray diffraction, FT-IR, SEM, TEM, XPS and BET, confirming that the Cs-POM active species retained its Keggin structure after immobilization. The substitution method of Cs-PMM exhibited more excellent catalytic performance for oxidative desulfurization of dibenzothiophene in the presence of oxygen. Under optimal conditions, the DBT conversion rate reached up to 99.6% and could be recycled 10 times without significant loss of catalytic activity, which is mainly attributed to the slow leaching of the active heteropolyacid species from the strong fixed effect of the mixture porous materials.

Simultaneous Electrochemical Exfoliation and Functionalization of Graphene By Diazonium Compounds

Covalent functionalisation of graphene is considered as one method for enhancing the processability of graphene for various applications. The majority of the study to-date has focused on the functionalization of pre-made graphene.1-3 In this contribution, we describe single stage simultaneous electrochemical exfoliation and functionalisation of graphene using diazonium compounds. Caesium salt (dissolved in dimethyl sulfoxide) as intercalating ions in combination with diazonium salt (either 4-nitrobenzenediazoniumtetrafluoroborate, 4-bromobenzenediazonium tetrafluoroborate or anthraquinone-1-diazonium chloride) as functionalisation moieties were used. Simultaneous exfoliation and functionalisation is beneficial for a number of reasons. First, the presence of diazonium salt in the exfoliation solution not only plays a role in functionalisation but also facilitate the exfoliation process through the generation of N2 gas which assists the separation of the functionalised graphene layers. Second, this process is selective for edge functionalisation and finally as both functionalisation and exfoliation occurs at the same time, monolayer or few layer graphene can be functionalised in situ before they aggregate. Significantly, functionalisation enhanced the dispersibility of graphene in aqueous solution and its solubility was two orders of magnitude larger than the non-functionalised electrochemically exfoliated graphene. As also shown in Figure 1, the functionalisation introduced surface active redox reactions when used as a supercapacitor electrode. The redox reactions enhanced the charge storage capacity of graphene and the specific capacitance found to be highly dependent on the degree of graphene functionalization. 1. J. R. Lomeda, C. D. Doyle, D. V. Kosynkin, W.-F. Hwang and J. M. Tour, J. Am. Chem. Soc., 2008, 130, 16201-16206. 2. E. Bekyarova, M. E. Itkis, P. Ramesh, C. Berger, M. Sprinkle, W. A. de Heer and R. C. Haddon, J. Am. Chem. Soc., 2009, 131, 1336-+. 3. J. Greenwood, T. H. Phan, Y. Fujita, Z. Li, O. Lvasenko, W. Vanderlinden, H. Van Gorp, W. Frederickx, G. Lu, K. Tahara, Y. Tobe, H. Uji-i, S. F. L. Mertens and S. De Feyter, ACS Nano, 2015, 9, 5520-5535. Figure 1. Cyclic voltammograms recorded at 100 mV s-1 in 6.0 M KOH (aq) using symmetrical coin cells constructed from electrochemical exfoliated restacked graphene and graphene functionalised insitu with 4-nitrobenzenediazoniumtetrafluoroborate (G-NBD). The voltage was swept between 0.0 V to 1.0 V Figure 1

Preparation of pyridine-stretched 2'-deoxyhypoxanthosine phosphoramidite

Pyridine-stretched 2!-deoxyhypoxanthosine (strH) phosphoramidite was prepared in eight steps from Hoffer’s sugar (2!-deoxy-3,5-di-O-(p-toluoyl)-α-D-erythro-pentofuranosyl chloride). Improved synthesis of the Hoffer sugar was achieved without need for distillation or chromatographic separation of intermediates, or use of gaseous HCl. Conditions were optimised to provide a key nitrile intermediate for the preparation of strH whereby the cesium salt of 4(5)-nitroimidazole was glycosylated using Hoffer’s sugar. The nitrile intermediate was also used to prepare pyridine-stretched 2!-deoxyadenosine (strA) and pyridine-stretched 2!-deoxy-diaminopurine (strD). Preliminary studies indicate that strH forms a stronger, size-expanded base pair with adenine compared with the Watson-Crick thymine-adenine base pair.