SYNTHETIC AND CATALYTIC PROPERTY STUDIES ON SILICA SUPPORTED BIS-(ACETYLACETONATO) COBALT(Ⅱ) COMPLEXES^(**)

This paper reports mainly the preparation of silica supported acetylacetone ligands and their cobalt complexes, the characterization of their chemical structure, and the evaluation of their catalytic activity in the reaction for the preparation of ethers directly from alkanols and benzyl chloride. The results indicate that those silica supported β-diketone cobalt complexes (SACO) not only can simplify the reaction procedure of the ether preparation but also show a much higher catalytic activity in comparison with other homogeneous catalysts. In addition, SACO can be recovered and reused although their catalytic activity descend gradually as a result of the decrease in their cobalt content.

THE CORRELATION BETWEEN ZrO_2 PHASE AND ITS CATALYTIC PROPERTY

In this letter, the preparation of three ZrO2 phases has beed briefly described and their catalytic results have been presented for CO hydrogenation to olefin. These catalysts had a good selectivity for light olefin. Monoclinic ZrO2 catalyst had a high selectivity for isobutene, while the other phase catalysts had not

Syntheses,crystal structures,and catalytic properties of three zinc(Ⅱ),cobalt(Ⅱ)and nickel(Ⅱ)coordination polymers constructed from 5⁃(4⁃carboxyphenoxy)nicotinic acid

Three zinc(Ⅱ),cobalt(Ⅱ),and nickel(Ⅱ)coordination polymers,namely[Zn(μ^(3-)cpna)(μ-dpea)_(0.5)]_(n)(1),[Co(μ^(3-)cpna)(μ-dpey)_(0.5)]_(n)(2),and[Ni(μ^(3-)cpna)(μ-dpey)_(0.5)(H_(2)O)]_(n)(3),have been constructed hydrothermally using H_(2)cpna(5-(4-carboxyphenoxy)nicotinic acid),dpea(1,2-di(4-pyridyl)ethane),dpey(1,2-di(4-pyridyl)ethylene),and zinc,cobalt,and nickel chlorides at 160℃.The products were isolated as stable crystalline solids and were characterized by IR spectra,elemental analyses,thermogravimetric analyses,and single-crystal X-ray diffraction analyses.Single-crystal X-ray diffraction analyses revealed that three compounds crystallize in the triclinic system,space group P1.Compounds 1-3 show 2D layer structures.The catalytic activities in the Knoevenagel condensation reaction of these compounds were investigated.Compounds 1 and 2 exhibit effective catalytic activities in the Knoevenagel condensa-tion reaction at room temperature.For this reaction,various parameters were optimized,followed by the investiga-tion of the substrate scope.CCDC:2335676,1;2335677,2;2335678,3.

Syntheses and catalytic performances of three coordination polymers with tetracarboxylate ligands

Three zincand cobaltcoordination polymers,namely{[Zn_(2)(μ_(6)-adip)(phen)_(2)]·4H_(2)O}_(n)(1),{[Co_(2)(μ_(6)-adip)(bipy)_(2)]·4H_(2)O}_(n)(2),and[Co_(2)(μ4-adip)(μ-bpa)_(2)]_(n)(3)have been constructed hydrothermally using H4adip(H4adip=5,5′-azanediyldiisophthalic acid),phen(phen=1,10-phenanthroline),bipy(bipy=2,2′-bipyridine),bpa(bpa=bis(4-pyridyl)amine),and zinc and cobalt chlorides at 160℃.The products were isolated as stable crystalline solids and were characterized by IR spectra,elemental analyses,thermogravimetric analyses,and single-crystal X-ray diffrac-tion analyses.Single-crystal X-ray diffraction analyses revealed that three compounds crystallize in the orthorhom-bic system Pnna(1 and 2)or P21212(3)space groups.All compounds exhibit 3D frameworks.The catalytic perfor-mances in the Henry reaction of these compounds were investigated.Compound 3 exhibited an effective catalytic activity in the Henry reaction at 70℃.CCDC:2339391,1;2339392,2;2339393,3.

A New Property of Conjugated Polymer PFP: Catalytic Degradation of Methylene Blue Aqueous Solution

A new property of conjugated polymer poly（furancarbinol-co-phenol）（PFP） was studied. The target copolymer was used as a catalyst after proper heating treatment. And dye methylene blue （MB） could be fully degraded and largely mineralized on PFP, under natural light or even in dark, in a few minutes. Furthermore, the catalytic activity could be preserved after several runs and the catalyst was readily separated. The effect of calcination temperature was also observed.

Electron Donating Property and Catalytic Activity ofPerovskite-type Mixed Oxides (ABO_3) Consisting of Rare Earth and 3d Transition Metals

The catalytic activity of Perovskite-type mixed oxides (LaCoO3, PrCoO3 and SmCoO3) for the reduction of cyclohexanone to cyclohexanol with 2-propanol (Meerwein-PonndorfVerley reduction) has been studied. The data have been correlated with the surface electron donor properties of these mixed oxides

Synthesis of Nano-sized Yttria via a Sol-Gel Process Based on Hydrated Yttrium Nitrate and Ethylene Glycol and Its Catalytic Performance for Thermal Decomposition of NH_4ClO_4

Nano-sized yttria particles were synthesized via a non-aqueous sol-gel process based on hydrated yttrium nitrate and ethylene glycol. The effects of the molar ratio of ethylene glycol to yttrium ion and calcination temperature on crystallite size of the products were studied. The catalytic performance of the as-prepared yttria for the ammonium perchlorate （AP） decomposition was investigated by differential scanning calorimetry （DSC）. The results indicate that the nano-sized cubic yttria particles with less than 20 nm in average crystallite size can be obtained after 2 h reflux at 70℃, dried at 90 ℃, forming xerogel, and followed by annealing of xerogel for 2 h, and that the addition of the nano-sized yttria to AP incorporates two small exothermic peaks of AP in the temperature ranges of 310 - 350 ℃ and 400 - 470 ℃ into a strong exothermic peak of AP and increases the apparent decomposition heat from 515 to over 1110 J·g^- 1. It is also clear that the temperature of AP decomposition exothermic peak decreases and the apparent decomposition heat of AP increases with the increase of the amount of nano-sized yttria. The fact that the addition of the 5 % nano-sized yttria to AP decreases the temperature of AP exothermic peak to 337.7℃ by reduction of 114.6℃ and increases the apparent decomposition heat from 515 to 1240 J·g^-1, reveals that nano-sized yttria shows strong catalytic property for AP thermal decomposition.

Catalytic Activity of Ceria-Zirconia Nanostructured Materials Prepared via Reversed Microemulsion Method

Single-phase homogeneous Ce1-x ZrxO2 solid versed microemulsion method. The structural properties solutions with various compositions were synthesized using the reand performance of Ce1- xZrxO2 were studied using XRD, BET, SEM, HRTEM, TPR and CO oxidation measurements. The results show that in the range of x = 0.4 - 0.5 and x = 0.6 - 1.0, the solid solutions posses the cubic and the tetragonal phase structure, respectively, Solids obtained by the reversed microemulsion method were more homogeneous on the whole range of composition, XRD investigations of the prepared materials did not show segregation of cerium or zirconium oxides, Highly uniform nanosize solid solution particles of ceria-zirconia with high specific area （146.7 m^2·g^-1） were attained under the conditions of this study. The TPR results and CO oxidation measurements indicate that the performance of the CeO2-ZrO2 mixed oxides is strongly related to the composition and structure of the oxides. Enhancement of the activity was found for the catalyst prepared by reversed microemulsion method as compared to the sample prepared by sol-gel method.

Synthesis, Crystal Structure and Catalytic Properties of a 2D Cobalt(II) Coordination Polymer Based on Mixed Ligands

A new Co（Ⅱ） metal-organic coordination polymer based on flexible bis（imidazole） and aromatic dicarboxylate co-ligands, namely [Co（bix）（nph）]n （H2nph = 3-nitrophthalic acid, bix = 1,4-bis（imidazole-l-ylmethyl）benzene）, has been hydrothermally synthesized and characterized by elemental analyses, TG, IR spectroscopy and single-crystal X-ray diffraction. It crystallizes in the triclinic space group Piwith a = 9.3767（14）, b = 10.1451（15）, c = 12.1488（17） A, α = 102.6450（10）, β = 108.856（2）, ）, = 98.807（2）°, V= 1035.3（3） A3, Z = 2, C22H17CoN5O6, Mr = 506.34, Dc = 1.624 g/cm^3, p = 0.882 mm^-1 and F（000） = 518. In the complex, the nph^2- ligands connect neighbouring cobalt atoms to form binuclear [Co（nph）]2 subunits, which are linked by pairs of bix ligands to form a 2D honeycomb-like （6,3） network. In addition, the compound is further extended into a 3D supramolecular architecture by π…π stacking interactions. Moreover, the luminescence and catalytic properties of the complex are investigated.

Synthesis of Mg_5(CO_3)_4(OH)_2·4H_2O with Flower-like Micro-structure and Its Catalytic Activity for Transesterification of Dimethyl Carbonate with Phenol

A novel flower-like hydrated magnesium carbonate hydroxide, Mg5 （CO3 ）4 （OH）2·4H2O, with micro-structure composed of individual thin nano-sheets was synthesized using a facile solution route without the use of template or organic surfactant. Reaction time has an important effect on the final morphology of the product. The micro-structure and morphology of Mg5 （CO3）4 （OH）2·4H2O were characterized by means of X-ray diffractometry （XRD）, fieldemission scanning electron microscopy（FE-SEM）. Brunauer-Emmett-Teller（BET） surface areas of the samples were also measured. The probable formation mechanism of flower-like micro-structure was discussed. It was found that Mg5 （CO3）4（ OH）2·4H2O with flower-like micro-structure was a novel and efficient catalyst for the synthesis of diphenyl carbonate （DPC） by transesterification of dimethyl carbonate （DMC） with phenol.

Two Cd(Ⅱ) Coordination Polymers Based on a Flexible Tricarboxylate Ligand: Syntheses, Structures, and Photoluminescence and Catalytic Properties

Studies on the synthesis and design of coordination polymers(CPs) with flexible ligands are of great interest owing to their dynamic structures and promising applications. The title coordination polymers, {[Cd·(HTTTA)·(phen)]·2HO}n(1) and [Cd·(HTTTA)·(phen)]n(2)(H3 TTTA = 2,2’,2’’-[1,3,5-triazine-2,4,6-triyltris(thio)] tris-acetic acid, phen = 1,10-phenanthroline) have been synthesized and characterized by elemental analysis, IR, powder XRD and single-crystal X-ray diffraction. Complex 1 consists of one CdII ion, one HTTTA2-ligand and one phen co-ligand. The Cd(Ⅱ) metal clusters were bridged by the tridentate HTTTA2-ligands into infinite 1D chains, which are further connected into the 3D architecture by abundant hydrogen bonds. In 2, three carboxyl groups of HTTTA2-ligand show different coordination directions because of the C–S–C flexible bond angle, which leads to different 1D chains of 2. The strong π-π stacking interaction and four C–H···O hydrogen bonds connect the 1D chains into a 3D framework. The solid-state photoluminescence and catalytic properties were studied as well.

Catalytic reduction of N_2O by CO over Pt_lAu-m^- clusters:A first-principles study

Based on the density functional theory, we investigate negatively charged clusters PtlAum^-（l ＋ m = 4）, which show significant catalytic properties in the simultaneous removal of N2O and CO. We find that in these clusters, the platinum atom acts as the adsorption center for N2O, the gold and Pt atoms act as electron donors during the reaction, and the charge transfers from the bimetallic cluster to the N2O molecule. As the proportion of Au in the cluster increases, the d band center shifts down further away from the Fermi level, meanwhile more charge is transferred to the N2O molecule, resulting in weaker N–O bond strength. Therefore bimetallic cluster PtAu3^- shows better catalytic properties than the other clusters,especially pure Pt4^- and Au4^-clusters. This means that there is a synergetic effect between the Pt and Au atoms in the negatively charged bimetallic clusters. Our results help to reveal the mechanism of PtlAum^- bimetallic clusters as excellent catalysts.

Crystal Structure and Catalytic Properties of Tetrakis (4-hydroxyphenyl) Porphyrinato Manganese(Ⅲ) Chloride (MnTHPPCl)

The crystal structure of meso-tetrakis （4-hydroxyphenyl） porphyrinato manganese chloride （MnTHPPC1） and its supramolecular architecture based on the hydrogen bonds of one counter C1 anion with four hydrogen atoms of four-OH groups from different MnTHPPC1 molecules cooperated by self-assembly of the porphyrin units were first repor-ted. This compound crystallized in the tetragonal space group 14/m with a = 1.39928（7） nm, b = 1.39928（7） nm, c =0.94498（10） nm, V= 1.8503（2） nm^3, and Z =2. As a catalyst, MnTHPPC1 also showed a high catalytic acti-vity in the conversion from 1-naphthylamine （1-NA） to his （4-oxo-benzo-2-cyclohexen-l-yl） amine （BOBCHA） v/a oxidative coupling under mild conditions.

Synthesis, Crystal Structure and Catalytic Properties of a New 2D Nickel(II) Coordination Polymer Based on Flexible Bis(benzimidazole)

A new Ni(II) coordination polymer [Ni(L)2(SCN)2]n(L = 1,4-bis(benzimidazol-1-yl)butane) was synthesized hydrothermally and characterized by elemental analysis, IR spectroscopy and single-crystal X-ray diffraction. The title compound crystallizes in the monoclinic system, space group C2/c with a = 9.4760(3), b = 24.0408(8), c = 16.5871(5) A, β = 99.832(3)°, V = 3723.2(2) A3, Z = 4, Dc = 1.348 g/cm3, F(000) = 1576, the final R = 0.0486 and w R = 0.0936 for 2938 observed reflections with I 】 2σ(I) for the complex. Structural analysis shows that the coordination polymer possesses a 2D(4,4) layer structure which is composed of Ni(II) centers bridged by L ligand with two kinds of conformations and further assembled into a 3D supramolecular network via π-π stacking interactions. In addition, the fluorescence and catalytic properties, for the degradation of Congo red, of the complex were investigated.

Facile Synthesis and Catalytic Properties of β-Co(OH)_2 and Mg(OH)_2 Nanoplates

β-Co（OH）2 and Mg（OH）2 nanoplates were synthesized via a facile template-free hydrothermal approach.The different conditions of preparation and catalytic properties of the products were studied and discussed.The products were characterized by X-ray diffraction,transmission electron microscopy,scanning electron microscopy,selected area electron diffraction（SAED）,and gas chromatograph.

Photocatalytical Inactivation of Enterococcus faecalis from Water Using Functional Materials Based on Natural Zeolite and Titanium Dioxide

The functional materials based on natural zeolite （clinoptilolite）, TiO2-zeolite and Ag-TiO2-zeolite have been successfully synthesized by solid-state reaction in fast-hydrothermal conditions. The obtained functional materials were investigated by X-ray diffraction （XRD）, FT-1R （Fourier transform infrared） spectroscopy, DRUV-VIS （diffuse reflectance ultraviolet-visible） spectroscopy, BET （Brunauer-Emmett-Teller） and SEM/EDX （scanning electron microscope/energy dispersive X-ray spectrometer） analyses. The XRD results indicated that the clinoptilolite structure has a good thermal stabilization after the fast-hydrothermal treatment. Also, the high specific surface area about 92.55 m^2.g^-1 was noticed for Ag-TiO2-zeolite functional material. The presence of dopants was evidenced from EDX spectra. The enhanced bactericidal activity of Ag-TiO2-zeolite catalyst is proved through damaging of Enterococcusfaecalis colonies under visible irradiation, at different material doses and irradiation times.

Effects of surface chemical properties of activated coke on selective catalytic reduction of NO with NH_3 over commercial coal-based activated coke

Surface chemical properties of typical commercial coal-based activated cokes were characterized by Xray photoelectron spectroscopy(XPS) and acid-base titration, and then the influence of surface chemical properties on catalytic performance of activated cokes of NO reduction with NH3 was investigated in a fixed-bed quartz micro reactor at 150 ℃. The results indicate that the selective catalytic reduction(SCR) activity of activated cokes with the increase of its surface acidic sites and oxygen content,obviously, a correlation between catalytic activity and surface acidic sites content by titration has higher linearity than catalytic activity and surface oxygen content by XPS. While basic sites content by acid-base titration have not correlation with SCR activity. It has been proposed that surface basic sites content measured by titration may not be on adjacent of acidic surface oxides and then cannot form of NO2-like species, thus the reaction of reduction of NO with NH3 have been retarded.

Effect of Fe_2O_3 Loading Amount on Catalytic Properties of Monolithic Fe_2O_3/Ce_(0.67)Zr_(0.33)O_2-Al_2O_3 Catalyst for Methane Combustion

Ce0.67Zr0.33O2-Al2O3 solid solution was prepared by the co-precipitation method. Fe2O3-based catalysts supported on the solid solution were obtained by the impregnation method. The article revealed that the optimal loading amount of Fe2O3 on Ce0.67Zr0.33 O2-Al2O3 in our experimental condition for catalytic combustion of methane was 8% （ mass fraction）. The prepared catalysts were characterized by BET, TPR, XRD analyses, and their catalytic activity was investigated after being calcined at 873 K and after being aged in water gas at 1273 K. When the loading amount of Fe203 was 8% （ mass fraction）, the catalyst held the highest activity, and the best temperature speciality and thermal stability. The complete-conversion temperature of methane for fresh and aged sample was 788 and 838 K, respectively. The range between the light-off temperature and the complete-conversion temperature was only 15 K. The characterization results of XRD indicated that Fe2O3 was well dispersed on the Ce0.67Zr0.33O2-Al2O3 matrix. The results of BET and TPR were in good harmony with the catalytic activity results.

Salt-Assisted Combustion Synthesis of NdCoO_3 Nanoparticles and Their Catalytic Properties in Thermal Decomposition of Ammonium Perchlorate

Highly dispersed perovskite NdCoO3 nanoparticles were prepared by a novel salt-assisted combustion process. The effects of NaCl content and calcination temperature on the characteristics of the products were characterized by X-Ray Diffraction (XRD), Transmission Electron Microscopy (TEM) and BET surface area measurement. The facile introduction of NaCl in the conventional combustion synthesis process was found to result in the formation of well-dispersed perovskite nanoparticles and increase specific surface areas of the resultants from 1.7 to 43.2 m2·g-1. The catalytic properties of the typical NdCoO3 samples for thermal decomposition of ammonia perchlorate (AP) and their correlation with the NdCoO3 microstructure were investigated by Differential Scanning Calorimetry (DSC). The DSC results indicate that the addition of the amorphous NdCoO3 nanoparticles to AP incorporates two small exothermic peaks of AP into a strong exothermic peak, decreases the temperature of the AP exothermic peak to 314.0 ℃ by reduction of 138.3 ℃ and increases the apparent decomposition heat from 515 J·g-1 to over 1441 J·g-1, showing the intense catalytic activity for thermal decomposition of AP. It is also clear that the catalytic activity of the resultant NdCoO3 is related to their microstructure. According to Kissinger′s method, the kinetics parameters of the thermal decomposition of AP catalyzed by the as-prepared NdCoO3 samples were calculated to account for the order of their catalytic activity.

Preparation and catalytic properties of ZrO_2-Al_2O_3 composite oxide supported nickel catalysts for methane reforming with carbon dioxide

ZrO 2-Al 2O 3 composite oxides and supported Ni catalysts were prepared, and characterized by N 2 adsorption /desorption, X-ray diffraction(XRD) an d X-ray photoelectron spectroscopy(XPS) techniques. The catalytic performance and carbon deposition was also investigated. This mesoporous composite oxide is shown to be a promising catalyst support. An increase in the catalytic activity and stability of methane and carbon dioxide reforming reaction was resulted from the zirconia addition, especially at 5wt% ZrO 2 content. The Ni catalyst supported ZrO 2-Al 2O 3 has a strong resistance to sintering and the carbon deposition in a relatively long-term reaction.