Microporous Copper Research Articles

Synthesis and characterization of a microporous copper triazolate as a water vapor adsorbent

To better understand the water vapor adsorption behavior of metal organic frameworks, a microporous copper triazolate was synthesized and used as a substrate to evaluate water vapor adsorption isotherms at four different temperatures (293, 303, 323 and 343 K). Samples of [ Cu 3 II (triazolate) 3(OH) 3(H 2O) 4]·4.5H 2O were obtained as powders by partially modifying a procedure reported in the literature and characterized by means of X-ray diffraction, scanning electron microscopy, particle size distribution, thermogravimetry and microporosimetric analysis. The experimental data for the water vapor adsorption were submitted to non-linear regression using the semiempirical Sips equation, which led to a good correlation between model curves and experimental points. Moreover, the dependence of the isosteric heat on the fractional coverage of the adsorbent was successfully calculated by the van’t Hoff equation and Sips theoretical isotherms.

Enhancement of Saturation Boiling of PF-5060 on Microporous Copper Dendrite Surfaces

Experiments are performed to investigate saturation boiling of degassed PF-5060 dielectric liquid on microporous copper dendrite surface layers deposited on 10×10 mm2 Cu substrates. The electrochemically deposited surface layers are of different thicknesses (145.6 μm, 46.3 μm, and 33.1 μm). The thickest layer gives the best results: the saturation CHF of 25.27 W/cm2 occurs at a surface superheat of only 2.9 K and the maximum nucleate boiling heat transfer coefficient, hMNB, near the end of the fully developed nucleate boiling region, is 8.76 W/cm2 K. In addition, nucleate boiling ensues at a surface temperature slightly above saturation (<0.5 K), with no temperature excursion. The temperature excursions before initiating boiling on the 46.3 μm and 33.1 μm thick Cu nanodendrite surface layers are small (3.7 K and 6 K), corresponding to surface temperatures of ∼55.1°C and 57.4°C, respectively. These temperatures are much lower than recommended (85°C) for reliable operation of most silicon electronics and central processor units.

The Use of a Nano- and Microporous Surface Layer to Enhance Boiling in a Plate Heat Exchanger

Presented research is an experimental study of the performance of a standard plate heat exchanger evaporator, both with and without a novel nano- and microporous copper structure, used to enhance the boiling heat transfer mechanism in the refrigerant channel. Various distance frames in the refrigerant channel were also employed to study the influence of the refrigerant mass flux on two-phase flow heat transfer. The tests were conducted at heat fluxes ranging between 4.5 kW/m2 and 17 kW/m2 with 134a as refrigerant. Pool boiling tests of the enhancement structure, under similar conditions and at various surface inclination angles, were also performed for reasons of comparison. The plate heat exchanger with the enhancement structure displayed up to ten times enhanced heat transfer coefficient in the refrigerant channel, resulting in an improvement in the overall heat transfer coefficient with over 100%. This significant boiling enhancement is in agreement with previous pool boiling experiments and confirms that the enhancement structure may be used to enhance the performance of plate heat exchangers. A simple superposition model was used to evaluate the results, and it was found that, primarily, the convective boiling mechanism was affected by the distance frames in the standard heat exchanger. On the other hand, with the enhanced boiling structure, variations in hydraulic diameter in the refrigerant channel caused a significant change in the nucleate boiling mechanism, which accounted for the largest effect on the heat transfer performance.

Preparation of Microporous Copper Foam with 3-Dimensionally Interconnected Pores by Electrodeposition

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New microporous copper(II) coordination polymers based upon bifunctional 1,2,4-triazole/tetrazolate bridges

A series of Cu(II) coordination polymers, [Cu(μ2-L1)3]PO3F (1), [Cu2(μ2-L1)4(μ4-L1)](NO3)4·2H2O (2), [Cu(μ2-L1)2(μ2-X)]X·12H2O (X = Cl, 3; Br, 4), [Cu4(μ2-OH)2(μ4-L1)3(μ2-L1)2(H2O)2](CF3SO3)6·10H2O (5), [Cu3(μ2-OH)2(μ4-L1)(H2O)2(μ3-SO4)2] (6), [Cu(μ4-L1)(μ2-SO4)]·6H2O (7), [Cu2(μ4-L2)3]Cl·12H2O (8) involving new bifunctional p-phenylene bridged bi(1,2,4-triazole) and mixed 1,2,4-triazole-tetrazolate based ligands (L1= 1,4-phenylene-4,4′-bi(1,2,4-triazole), HL2= 5-(4-[1,2,4]triazol-4-yl-phenyl)-1H-tetrazole) has been prepared under hydrothermal conditions and their structures have been established by means of X-ray diffraction. In crystal structures 1–8, the organic ligands, utilizing two neighboring nitrogen atoms (N1, N2 in triazole (trz) and N2, N3 in tetrazolate), behave either in μ2 or in μ2 + μ4 manner binding the adjacent metal centers or Cu3(μ2-OH)2 clusters into 1D columns (1, 3, 4), 2D zigzag layers (2) and 3D frameworks (5–8). The mutual coplanarity between uncoordinated trz moiety and p-phenylene spacer as well as its radial disposition around the “propeller-like” [Cu2(η2-trz)3] subunits is a crucial factor, which specifically mediates multiple π–π interactions through intercalation of the neighboring Cu(η2-trz)n (n = 2,3) axles, and as a consequence, affording one-dimensional channels with trigonal (1, 2) or rhombic geometry (3, 4). Large rectangular channels have been realized in neutral [Cu(μ4-L1)(μ2-SO4)]n (7) and cationic [Cu2(μ4-L2)3]nn+ (8) frameworks, in which the remaining void space is filled by water molecules and counter anions (Cl−).

A Tetrahedral Organophosphonate as a Linker for a Microporous Copper Framework

Vertauschte Rollen: Ein Kupferphosphonatnetzwerk wird mit einem ligandengesteuerten statt einem clustergesteuerten Ansatz hergestellt. Das sich doppelt durchdringende diamantartige Gerüst (siehe Kalottenmodell) enthält zugängliche Mikroporen, wie CO2-Sorptionsexperimente belegen.

A Tetrahedral Organophosphonate as a Linker for a Microporous Copper Framework

Role reversal: A copper phosphonate network is synthesized using a ligand-directed, rather than a cluster-directed, approach. The doubly interpenetrated diamondoid framework (see space-filling representation) contains accessible micropores, as demonstrated by CO2 sorption experiments.

2562 パウダースペースホルダー法により作製したマイクロポーラス金属の機能特性の評価(S25-2 多孔質材(2),S25 新機能多孔質材料の創製と評価)

This study aims to evaluate the functional properties such as heat radiation performance and water absorption power of micro-porous metals produced by powder space holder method To investigate the effects of pore size on heat radiation performance, the heat transfer coefficients of micro-porous copper specimens were measured under various air flow rates. Also, to know the water absorption behavior of micro-porous metals, the weight change of porous stainless-steel specimens in a water immersion was evaluated.

Oxidation catalysis of microporous metal carboxylate complexes

Abstract A microporous copper(II) carboxylate complex, copper(II) trans -1,4-cyclohexanedicarboxylate [Cu 2 II,II (OOCC 6 H 10 COO) 2 ]·H 2 O ( 1 ) can act as a biomimetic heterogeneous catalyst for selective oxidation of various alcohols with H 2 O 2 . A green-colored active intermediate, H 2 [Cu 2 II,II (OOCC 6 H 10 COO) 2 (O 2 )]·H 2 O ( 2 ), observed in the reaction of 1 with 20-fold excess H 2 O 2 in acetonitrile was characterized by elemental analysis, TG/DTA, magnetic susceptibility, FT-IR, diffuse reflectance (DR) UV–vis, electron paramagnetic resonance (EPR), X-ray powder diffraction (XRPD), resonance Raman, BET surface area, pore size distribution, and nitrogen occlusion measurements. The molecular structure of 2 was determined from XRPD data and refined by the Rietveld method. The microporous structure of 2 was constructed by intermolecular bridging of μ-1,2- trans Cu–OO–Cu species between two-dimensional [Cu 2 (O 2 CC 6 H 10 CO 2 )] layers, which was the first example of microporous copper(II) peroxo complex for heterogeneous oxidation catalysis. Moreover, a microporous ruthenium(II,III) complex having porphyrin [Ru II,III 2 (H 2 TCPP)]BF 4 ( 3 ) (H 2 TCPP = 4,4′,4″,4‴-(21H,23H-porphine-5,10,15,20-tetrayl)tetrakis benzoic acid) particularly exhibited an effective catalytic performance for the heterogeneous oxidation of primary aliphatic alcohols with dioxygen and air without any additives at room temperature. The reaction pathway included the formation of an Ru–oxygen radical intermediate, which was due to the high affinity of diruthenium(II,III) sites for dioxygen.

X-ray absorption spectroscopic studies on novel microporous copper containing catalytic systems

Novel copper metal modified microporous aluminosilicate and aluminophosphate catalysts with the high phase purity were synthesized and characterized. CuK-edge XAS measurements were carried out over a series of copper containing SAPO-34 and ZSM-5 catalysts. EXAFS technique was used to obtain specific climacteric information related to the copper atomic distances, coordination and near neighbour environments. EXAFS studies indicated the presence of different of Cu species on ZSM-5/SAPO34 catalysts.

Critical Heat Flux for Downward Facing Boiling on a Coated Hemispherical Surface

An experimental study was performed to investigate the effect of surface coating on the critical heat flux for downward facing boiling on the outer surface of a hemispherical vessel. Steady-state boiling experiments were conducted in the subscale boundary layer boiling (SBLB) facility using test vessels with metallic microporous coatings to obtain the local boiling curves and the local critical heat flux (CHF) limits. Similar heat transfer performance was observed for microporous aluminum and microporous copper coatings. When compared to the corresponding data without coatings, the boiling curves for the coated vessels were found to shift upward and to the right. This meant that the CHF limit was higher with surface coating and that the minimum film boiling temperatures were located at higher wall superheats. In particular, the microporous coatings were found to enhance the local CHF values appreciably at all angular locations explored in the experiments. Results of the present study showed that the microporous aluminum coating was very durable. Even after many cycles of steady state boiling, the vessel coating remained rather intact, with no apparent changes in color or structure. Although similar heat transfer performance was observed for microporous copper coatings, the latter were found to be much less durable and tended to degrade after several cycles of boiling.

Microporous dinuclear copper(II) trans-1,4-cyclohexanedicarboxylate: heterogeneous oxidation catalysis with hydrogen peroxide and X-ray powder structure of peroxo copper(II) intermediate

A two-dimensional microporous dinuclear copper(II) trans-1,4-cyclohexanedicarboxylate, [Cu II,II 2(OOCC 6H 10COO) 2] ⋅ H 2O ( 1), can act as a heterogeneous catalyst for selective oxidations of various alcohols with hydrogen peroxide. Complex 1 catalyzed the selective oxidations of 2-propanol, cyclohexanol, benzyl alcohol, 2-octanol, and 1-octanol with >99% selectivities in a heterogeneous system. A green-colored active intermediate, H 2[Cu II,II 2(OOCC 6H 10COO) 2(O 2)] ⋅ H 2O ( 2), observed in the reaction of 1 with a 20-fold excess H 2O 2 in acetonitrile was characterized by elemental analysis, TG/DTA, magnetic susceptibility, FT-IR, diffuse reflectance UV–vis, EPR, X-ray powder diffraction (XRPD), resonance Raman spectra, BET surface area, pore size distribution, and nitrogen occlusion measurements. The molecular structure of 2 was determined from XRPD data and refined by the Rietveld method. The microporous structure of 2 was constructed by intramolecular bridging of μ-1,2- trans Cu OO Cu species between two-dimensional [Cu 2(O 2CC 6H 10CO 2)] layers. The complex 2 was the first example of the microporous copper(II) peroxo complex for heterogeneous oxidation catalysis.

A novel microporous copper silicate: Na2Cu2Si4O11·2H2O

The synthesis and structural characterisation of a thermally stable novel three-dimensional microporous copper silicate open-framework are described; the material is capable of undergoing reversible zeolitic water removal without destruction of the framework.

Formation of a one-dimensional array of oxygen in a microporous metal-organic solid.

We report the direct observation of dioxygen molecules physisorbed in the nanochannels of a microporous copper coordination polymer by the MEM (maximum entropy method)/Rietveld method, using in situ high-resolution synchrotron x-ray powder diffraction measurements. The obtained MEM electron density revealed that van der Waals dimers of physisorbed O2 locate in the middle of nanochannels and form a one-dimensional ladder structure aligned to the host channel structure. The observed O-O stretching Raman band and magnetic susceptibilities are characteristic of the confined O2 molecules in one-dimensional nanochannels of CPL-1 (coordination polymer 1 with pillared layer structure).

Physical stability vs. chemical lability in microporous metal coordination polymers: a comparison of [Cu(OH)(INA)]n and [Cu(INA)2]n: INA = 1,4-(NC5H4CO2).

Two microporous copper isonicotinate polymers [Cu(OH)(INA)] and [Cu(INA)2] have been formed hydrothermally in good yield and purity; each have 1D channels of ca. 4 x 6 A dimension, but with quite different hydrophilicities; both frameworks retain structural integrity to above 200 degrees C, however whilst [Cu(OH)(INA)] is also chemically stable, [Cu(INA)2] is highly labile and readily transforms to the molecular complex [Cu(INA)2(H2O)4] in water at room temperature.

Microporous fine-grained copper: Structure and properties

Abstract Powder metallurgy processing has been used to produce copper compacts with fine grain sizes (1-10 μm) that are pinned by submicron-size to micron-size gas-filled voids in the volume fraction range 0.05-0.2. The effect of subsequent heat treatment on the grain size and void size and shape was quantified. These changes strongly depended on whether the powder was consolidated using a coldpressing-and-sintering route, or hot pressing; thus the pressed and sintered compacts densified further whereas the hot-pressed compacts exhibited swelling during subsequent thermal exposure. Such materials were mechanically tested in compression and tension at room temperature, and high yield strength, attributed to grain-size strengthening, was recognized. Tensile ductility in excess of 20% was simultaneously obtained although some unusual features, atypical of fcc metals, including upper and lower yield points and a low work-hardening rate were noted. Approximate calculations examining the interaction of dislocat...

Microporous fine-grained copper: structure and properties

Microporous fine-grained copper: structure and properties

Characterization of Microporous Copper(II) Dicarboxylates (Fumarate, Terephthalate, and trans-1,4-Cyclohexanedicarboxylate) by Gas Adsorption

Abstract Some microporous coordination polymers have been synthesized from copper salts and dicarboxylic acids. These stuctures were characterized by gas adsorption methods. The methane adsorption capacities of these coordination polymers were measured under high pressure. The measurement disclosed that these coordination polymers had uniform micropores and methane adsorption capacities almost the same as that of zeolite 5A.

ChemInform Abstract: Microporous Materials of Metal Carboxylates

Copper(II) terephthalate absorbs a large amount of gases such as N2, Ar, O2, and Xe. The maximum amounts of absorption of gases were 1.8, 1.9, 2.2, and 0.9 mole per mole of the copper(II) salt for N2, Ar, O2, and Xe, respectively, indicating that the gases were not adsorbed on the surface but occluded within the solid. Other microporous copper(II) dicarboxylates are also reviewed. The porous structure of copper(II) terephthalate, in which the gas is occluded, is deduced from the temperature dependence of magnetic susceptibilities and the linear structure of terephthalate. Microporous molybdenum(II) and ruthenium(II, III) dicarboxylates are discussed. We describe that rhodium(II) monocarboxylate bridged by pyrazine form stable micropores by self-assembly of infinite linear chain complexes.

Microporous Materials of Metal Carboxylates

Copper(II) terephthalate absorbs a large amount of gases such as N2, Ar, O2, and Xe. The maximum amounts of absorption of gases were 1.8, 1.9, 2.2, and 0.9 mole per mole of the copper(II) salt for N2, Ar, O2, and Xe, respectively, indicating that the gases were not adsorbed on the surface but occluded within the solid. Other microporous copper(II) dicarboxylates are also reviewed. The porous structure of copper(II) terephthalate, in which the gas is occluded, is deduced from the temperature dependence of magnetic susceptibilities and the linear structure of terephthalate. Microporous molybdenum(II) and ruthenium(II, III) dicarboxylates are discussed. We describe that rhodium(II) monocarboxylate bridged by pyrazine form stable micropores by self-assembly of infinite linear chain complexes.