A tetranuclear ferric Keggin sandwich-type heteropolyanion has been synthesized by the reaction of lacunary species Delta-Na(8)H[PW(9)O(34)] with FeCl(2) followed O(2) oxidation in nonaqueous media. The structure [(n-C(4)H(9))(4)N](6)[Fe(III)(4)(H(2)O)(2)(PW(9)O(34))(2)].4CH(3)CN.2CH(2)Cl(2).2H(2)O (TBA-1) was determined single-crystal X-ray diffraction (orthorhombic, Pbca; R = 0.0693 for 14 963 reflections F(o) > 4sigma(F(o))). compound further characterized infrared and UV-visible...

The reaction of [P2W15O56]12- and aqueous Fe3+ forms two ferric polytungstophosphate derivatives that have been isolated, purified, characterized by X-ray crystallography several physical methods. At pH ∼3 [Na+] = 2 M, needles Na12[FeIII4(H2O)2(P2W15O56)2]·58H2O, Na-1, form, in which the conventional ion packing arrangement solid heteropoly acids is observed: each polyanion, [FeIII4(H2O)2(P2W15O56)2]12- (1), well separated cations (Na+). ∼1 1 however, elongated prisms...

The degradation of 4-chlorophenol with near-UV light by silica-immobilized polyoxometalate (POM-in-SiO2) catalysts has been studied. Na6W7O24 (SW7), H4W10O32 (SW10), H3PW12O40 (SPW12), and H6P2W18O62 (SP2W18) were prepared means the sol−gel hydrothermal technique through hydrolysis tetraethoxysilane in aqueous solution corresponding polyoxometalate, respectively. was monitored measuring Cl- CO2 concentrations analyzing reaction intermediates GC/MS analysis. During irradiation, first...

Reaction of α-P2W15O5612- and Fe(III) in a saturated NaCl solution produces trisubstituted Wells−Dawson structure with three low-valent metals, α-(FeIIICl)2(FeIIIOH2)P2W15O5911- (1). Dissolution this species into 1 M NaBr (Br- is noncoordinating) gives the triaquated α-(FeIIIOH2)3P2W15O599- (2). Ionic strength values or greater are necessary to avoid decomposition 2 conventional sandwich-type complex, αββα-(FeIIIOH2)2FeIII2(P2W15O56)212- (3). If pH than 5, new triferric sandwich,...

In spool valves, there is a fit gap between and sleeve, the valve internal leakage inevitable. For problem of excessive after assembly qualified parts, taking certain type jet pipe servo as an example, probability density curve through mathematical derivation by establishing dimension chain about combining with distribution part dimensions reached. Simulation different gaps using ansys fluent, combined laws component rings in chain, plot image its are derived.

The structural and chemical stabilities of immobilized polyoxometalate (POM)-containing catalysts are crucial factors for their industrial application. An alumina supported POM catalyst is prepared by using a facile condensation reaction between the trilacunary Na12 [α-P2 W15 O56 ]⋅24 H2 O (P2 ) hydroxy groups on surface γ-Al2 O3 spheres under acidic conditions. heterogeneous P2 -Al2 characterized wide variety techniques shows excellent stability highly efficient reactivity selectivity...

The Co-substituted heteropolyanions [Co4P2W18O68]10- and [CoPW11O39]5- catalyze the highly selective epoxidation of disubstituted alkenes stilbenes by p-cyano-N,N-dimethylaniline N-oxide (CDMANO). Terminal are not readily epoxidized. following d-electron transition metal-substituted (TMSP) complexes less two orders magnitude reactive than Co complexes: [MnIIIPW11O39]4-, [MnIIPW11O39]5-, [FeIIIPW11O39]4-, [NiIIPW11O39]5-. system (TBA)8H2[Co4P2W18O68] (TBA = n-Bu4N+) (TBA1)/CDMANO/alkene/CH3CN...

The simple and cost-efficient preparation of high-performance nitrogen-doped carbon aerogel (N-CA) for supercapacitors other applications is still a big challenge. In this work, we have presented facile strategy to synthesize hierarchically porous N-CA, which based on solvothermal polymerization phenol formaldehyde under hypersaline condition with ethylenediamine (EDA) functioning as both catalyst nitrogen precursor. Benefited from the catalytic effect EDA polymerization, obtained N-CA has...

Dry gas seals with extremely low leakage are the preferred sealing technology in supercritical carbon dioxide (SCO2) Brayton cycle. However, dry subject to a significant risk of CO2 phase transitions on seal face, which has yet be numerically investigated. A comparison study SCO2 two typical inlet temperatures is presented this article. The clearance, rate, and mass fraction under different pressures analyzed, along further insights into expansion process. Some operating design...

Purpose The purpose of this paper is to enhance sealing and rotordynamic performance hole-pattern damping seal (HPDS) labyrinth (LS) by structural innovation geometrical optimization special-shaped hole or annular-groove cavity. Design/methodology/approach unsteady flow was transformed into steady one using moving reference frame method. full period numerical models LS HPDS were established. influence cavity at axial inclined angle on leakage rate coefficient these two seals different whirl...

Eupholathone, a minor diterpenoid with an unusual tetracyclic skeleton, was obtained from the seeds of Euphorbia lathyris, along two known lathyrane diterpenoids, euphorbia factors L 2 and 3 . The structure eupholathone elucidated by detailed interpretation its spectroscopic data, especially two-dimensional nuclear magnetic resonance spectroscopy high-resolution electrospray ionization mass spectrometry.

Abstract Reasonable design of the cavity shape damping hole effectively reduces leakage rate hole-pattern seal (HPDS). A novel HPDS with dovetail-like diversion grooves was proposed, and geometry outline groove described by using hyperelliptic curve. Computational fluid dynamics commercial software used to simulate three-dimensional flow field (D-HPDS). The characteristics seals a typical circular hole, leaf-like were compared numerically experimentally. three-velocity zone model proposed...

Lithium silicate is an important sorbent to capture CO2. Herein, hollow microellipsoids of lithium with mesoporosity were prepared by a hydrothermal method using Na-montmorillonite and hydrate as raw materials. X-ray diffraction, scanning electron microscope transmission analysis show that the crystal phase products composed particle morphology sample microellipsoid at around 600 nm. Furthermore, wall constituted mesopores nanoparticles size range within 20 40 The specific area aperture...

Lithium silicate is an important sorbent to capture CO2. Herein, hollow microellipsoids of lithium with mesoporosity were prepared by a hydrothermal method using Na-montmorillonite and hydrate as raw materials. X-ray diffraction, scanning electron microscope transmission analysis show that the crystal phase products composed particle morphology sample microellipsoid at around 600 nm. Furthermore, wall constituted mesopores nanoparticles size range within 20 40 The specific area aperture...