Tuning of the textural features and acidic properties of sulfated mesoporous lanthana-zirconia solid acid catalysts for alkenylation of diverse aromatics to their corresponding α-arylstyrenes

The textural features and acidic properties of sulfated mesoporous lanthana‐zirconia solid acids （SO42？/meso‐La0.1Zr0.9Oδ） were efficiently tuned by modifying the conditions used to prepare the meso‐La0.1Zr0.9Oδcomposites, such as the molar ratio of the template to La and Zr metal ions （Nt/m）, molar ratio of ammonia to La and Zr metal ions （Na/m）, hydrothermal temperature （Thydro）, and hy‐drothermal time （thydro）. The effect of the textural features and acidic properties on the catalytic performance of solid acid catalysts for alkenylation of p‐xylene with phenylacetylene was investi‐gated. Various characterization techniques such as N2 physisorption, X‐ray diffraction, NH3 temper‐ature‐programmed desorption, and thermogravimetric analysis were employed to reveal the rela‐tionship between the nature of catalyst and its catalytic performance. It was found that the catalytic performance significantly depended on the textural features and acidic properties, which were strongly affected by preparation conditions of the meso‐La0.1Zr0.9Oδcomposite. Appropriate acidic sites and high accessibility were required to obtain satisfactory catalytic reactions for this reaction. It was also found that the average crystallite size of t‐ZrO2 affected by the preparation conditions had significant influence on the ultrastrong acidic sites of the catalysts. The optimized SO42？/meso‐La0.1Zr0.9Oδcatalyst exhibited much superior catalytic activity and coke‐resistant stabil‐ity. Moreover, the developed SO42？/meso‐La0.1Zr0.9Oδcatalyst demonstrated excellent catalytic per‐formance for alkenylation of diverse aromatics with phenylacetylene to their correspondingα‐arylstyrenes. Combining the previously established complete regeneration of used catalysts by a facile calcination process with the improved catalytic properties, the developed SO42？/meso‐La0.1Zr0.9Oδ solid acid could be a potential catalyst for industrial production ofα‐arylstyrenes through clean and atom efficient solid‐acid‐mediated Friedel‐Crafts alkenylation of diverse aromatics with phenylacetylene.

Synthesis of NbFAPO-5 and NbFAPSO-5 Molecular Sieve by Hydrothermal Method and Comparison of Their XRD Patterns and Their Acidic Properties Evaluation by Infrared Spectroscopy

Mesoporous molecular sieves, NbFAPO-5 and NbFAPSO-5 were hydrothermally synthesized with AlPO-5 type structure. Characterization of these molecular sieves was performed by X-ray diffraction to determine their structure, ICP-EAS for their elemental composition and infrared spectrometry to access their acidic properties. X-ray diffraction patterns confirmed well AlPO-5 type structure. ICP-EAS analysis confirmed the incorporation of silicon (12.9%), aluminium (15.4%), phosphorous (21.9%), iron (5.62%) and niobium (0.39%) into AlPO-5 framework. Infrared spectrometry analysis showed that both Bronsted and Lewis sites were found in the synthesized samples. The presence of both Bronsted and Lewis acid site led to bifunctional function of NbFAPO-5 and NbFAPSO-5 molecular sieve in promoting both oxidation and esterification reactions. NbFAPSO-5 Bronsted acidity was higher than that of NbFAPO-5 and for Lewis acidity, NbFAPO-5 was higher than that of NbFAPO-5.

Crystal Structure and Magnetic Properties of a Dinuclear Terbium Compound Tb_2(μ_2-anthc)_4(anthc)_2(1,10-phen)_2

A dinuclear Tb（Ⅲ） compound, Tb_2（μ_2-anthc）_4（anthc）_2（1,10-phen）_2（1, Hanthc = 9-anthracenecarboxylic acid and 1,10-phen = 1,10-phenanthroline）, was synthesized under solvothermal condition and structurally characterized by single-crystal X-ray diffraction. Compound 1 crystallizes in the triclinic system, space group P1, with a = 12.5061（12）, b = 13.3168（10）, c = 15.0079（12） ？, α = 110.620（7）, β = 102.941（7）, γ = 107.036（7）o, V = 2081.8（3） ？~3, Z = 1, C_（114）H_（70）N_4O_（12）Tb_2, M_r = 2005.58, D_c = 1.600 g/cm^3, μ = 1.759 mm^（-1）, F（000） = 1008, the final R = 0.0294 and w R = 0.0608 for 8900 observed reflections with I 〉 2s（I）. In compound 1, two Tb（Ⅲ） ions are linked by four carboxylate groups of the bridging anthc– ligands to give a dinuclear Tb_2（μ_2-anthc）_4 unit wherein each Tb（III） ion is further capped by a terminal anthc– ligand and a 1,10-phen ligand in a chelating fashion. Detailed direct-current and alternating-current susceptibility measurements showed no slow magnetism relaxation phenomenon was observed for 1.

Syntheses,Crystal Structures,and Magnetic Properties of Two Manganese(Ⅱ) Coordination Polymers Based on Bifunctional Pyridine-benzene Carboxylic Acids

Two manganese（II） coordination polymers, namely, {[Mn（PIP）（BIBP）]·（BIBP）0.5}n（1） and {[Mn（PTA）（BIMBP）（H2O）]·H2O（0.69）}n（2）（H2PIP = 5-（4-pyridyl）-isophthalic acid, H2 PTA =6-（4-pyridyl）-terephthalic acid, BIBP = 4,4？-bis（imidazol-1-yl）biphenyl, and BIMBP =4,4？-bis（imidazol-1-ylmethyl）biphenyl）, have been synthesized by using the bifunctional pyrinde-benzene carboxylic acids and bis（imidazole） linkers as mixed ligands to react with Mn SO4,and further characterized by elemental analysis, IR, and PXRD. Compound 1 is in the triclicnic system, space group P1 with a = 10.1089（8）, b = 13.1927（12）, c = 14.0638（12）A, α = 69.437（2）, β= 73.2890（10）, γ = 78.5320（10）o, V = 1671.9（2） A^3, Z = 2, Dc = 1.449 g/cm^3, F（000） = 705,μ（MoK α） = 0.453 mm^-1, S = 1.053, R = 0.0491 and wR = 0.1367 for 5837 unique reflections（Rint =0.0208） with I 〉 2σ（I）. Compound 2 belongs to the monoclicnic system, space group C2/c with a =15.199（3）, b = 19.731（3）, c = 21.537（5） ？, β = 105.228（3）o, V = 6232（2） A^3, Z = 8, Dc = 1.363g/cm^3, F（000） = 2648, μ（MoK α） = 0.475 mm^-1, S = 1.048, R = 0.0489 and wR = 0.1151 for 7414 unique reflections（Rint = 0.0425） with I 〉 2σ（I）. Structural analyses reveal that complex 1 is a4-connected（44.62）-sql bilayer structure with binuclear [Mn2（COO）2] SBU, while complex 2 is a normally（3,5）-connected（42.67.8）（42.6）-3,5L2 monolayer. And the sheets interacted with the adjacent sheets through weak interactions, finally giving a stable three-dimensional（3D）supramolecule. Besides, the variable-temperature magnetic susceptibility measurement of complex1 was investigated.

Syntheses,Crystal Structures,and Magnetic Properties of Cobalt(Ⅱ) Complexes with 1,1-Cyclohexanediacetic Acid

Two new Co（Ⅱ） coordination polymers,{[Co_3（Hchda）_2（chda）_2（bpp）_2（H_2O）_2]}_n 1 and {[Co（chda）（bpe）（H_2O）]·3H_2O}_n 2（H_2chda = 1,1-cyclohexanediacetic acid,bpp = 1,3-bis（4-pyridinyl）propane and bpe = 1,2-bis（4-pyridinyl）ethylene）,were hydrothermally synthesized and then characterized by elemental analysis,IR spectroscopy,thermogravimetric analysis（TGA）,and single-crystal X-ray diffraction.Complex 1 possesses an infinite metal-organic layer based on triply bridged linear trinuclear subunits and complex 2 exhibits a square（4,4） grid layer with dangling lateral arms resulting from eight-membered rings above and below the layer.In addition,magnetic properties of complexes 1 and 2 are also given.

Synthesis,Fluorescence and Magnetic Properties of a New Europium(Ⅲ) Complex Eu(L)3(Phen)2

A new europium（III） complex Eu（L）3（Phen）2（1） with 2-benzoylbenzoic acid（HL） and 1,10-phenanthroline（Phen） as ligands has been synthesized. Crystal data for the complex are as follows： monoclinic, space group P21/c, a = 2.2577（4）, b = 1.23484（19）, c = 1.8789（3） nm, β = 94.918（3）o, V = 5.2189（14） nm^3, Dc = 1.512 g/cm^3, Z = 4, μ（Mo Kα） = 1.269 mm^-1, F（000） = 2408, the final R = 0.0433 and w R = 0.1038. The Eu（III） ion is coordinated by nine atoms to give a single-capped square antiprism coordination geometry. 1 shows two intense fluorescence emission bands arising from the transitions of Eu^3＋： ^5D0→^7F1（597 nm） and ^5D0→^7F2（615 nm） with an excitation wavelength of 396 nm. In addition, 1 displays antiferromagnetic property at low temperature.

Effect of x-alumina addition on H_2S oxidation properties of pure and modified y-alumina

The influence of the textural and acidic properties ofγ‐Al2O3,(γ+χ)‐Al2O3,and?‐Al2O3on the catalytic activity,selectivity,and stability of direct H2S oxidation has been studied.A comparison of the H2S‐to‐S conversion effectiveness of aluminas with their acidic properties(identified by Fourier transform infrared spectroscopy and temperature programmed desorption of NH3)shows that H2S adsorption occurs predominantly on weak Lewis acid sites(LAS).γ‐Alumina samples containing aχ‐phase and/or modified Mg2+ions have a greater concentration of weak LAS and exhibit greater catalytic activity.When alumina is treated with a sulfuric acid solution,strong LAS appear and the number of LAS decreases significantly.Modification of alumina with hydrochloric acid has a limited effect on LAS strength.Weak LAS are retained and double in number compared to that present in the unmodified alumina,but the treated sample has Al?Cl bonds.Alumina samples modified by sulfate and chloride anions exhibit poor catalytic activity in H2S oxidation.

Preparation and Properties of Heat Resistant Polylactic Acid(PLA)/Nano-SiO2 Composite Filament

In order to improve the thermal properties of polylactic acid（PLA） filament,nano-SiO_2 was applied to mix with PLA,then they were spun as composite filament by melt-spinning.The dispersion of nano SiO_2 and the fracture surfaces of filaments were studied by scanning electron microscopy（SEM）.The properties of composite filament,such as orientation degree,mechanical properties,and surface friction properties,were analyzed.The thermal performances of composite filament were analyzed by differential scanning calorimetry（DSC） and thermo gravimetric analysis（TGA）.The results showed that the nano-SiO_2 modified by 5% KH-550 could disperse evenly and loosely in nano-scale,and 1 wt% and 3 wt% nano-SiO_2 dispersed throughout PLA evenly.As the quantity of nano-SiO_2 increased,the properties of composite filament,such as orientation degree,friction coefficient,thermal decomposition temperature,and glass transition temperature,increased more or less.The breaking tenacity increased when 1 wt% SiO_2 was added in PLA,but declined when 3 wt% SiO_2 was added.

Hydrothermal Synthesis,Crystal Structure and Properties of a Novel 3D Metal-organic Coordination Polymer with Helical Chains Based on 5-(Imidazol-1-ylmethyl)isophthalic Acid

A novel 3D metal-organic coordination polymer with helical chains based on a flexible 5-（imidazol-1-ylmethyl）isophthalic acid（H_2L） as a main ligand and 1,2-bis（4-pyridyl）ethane（bpa） as a N-containing ancillary ligand,[Cd L（bpa）_（0.5）]_n（1）,has been obtained under hydrothermal conditions and characterized by elemental analysis,powder X-ray diffraction（PXRD）,IR,thermal gravimetric analyses（TGA） and single-crystal X-ray diffraction.It crystallizes in monoclinic,space group P2_1/c with a = 10.984（2）,b = 10.1829（12）,c = 17.782（3） A,β = 123.156（11）o,V = 1665.1（5） A^3,Z = 4,Mr = 448.72,Dc = 1.790 g/cm^3,Rint = 0.0871,F（000） = 892,the final R = 0.0687 and w R = 0.1294 for 2920 observed reflections（I 〉 2σ（I））.In complex 1,the L^2- anions connect Cd（Ⅱ） ions to form two-dimensional metal-organic layers（Cd_2L_2）n,in which the 1D helical chains（Cd-L）_n are alternately arranged in a right-and left-handed sequence.These layers are further linked to build a 3D network by the bpa ligand.In addtion,photoluminescent properties for 1 are also investigated.

SUIDIES ON SOME PROPERTIES AND CATALYSIS OF RARE EARTH HETEROPOLY ACIDS

INTRODUCTIONThough potassium salts of rare earth substituted silicotungsticacids were synthesized early in 1971 by R.D.Peacock etc.,sofar the reports about the application of the corresponding acidshave not been found.We prepared fourteen rare earth substitutedsilicotungstic acids and determined their thermal stability,IRabsorption Spectra and x-ray diffraction spectra.Furthermore,thecatalytic activities of the fourteen heteropoly acids in acid cata-lytic reaction were investigated.Our experimental results demonstrated rare earth substituted silico-tungstic acids have very high catalytic activity in the reaction of

Promoted effect of zinc–nickel bimetallic oxides supported on HZSM-5 catalysts in aromatization of methanol

Zn/ZSM-5（NZ2） and Zn/Ni/ZSM-5（NZ3） as the catalysts for methanol to aromatics（MTA） were synthesized by a simple ultrasonic impregnation. The textural and acid properties of all catalysts were characterized using XRD, HRTEM, NH;-TPD, Py-IR, XPS, XRF and TG techniques. The XRD and HRTEM results showed that the basic zeolite structures were not affected much with the incorporation of Zn and Ni species. However, great changes have taken place in acid properties. The Py-IR and XPS results indicated that the Zn-Lewis acid sites（ZnOH;species）, which have stronger interaction with the zeolite framework compared with ZnO species, were generated at the expense of B acid sites with the incorporation of zinc species. Moreover, the product analysis results showed that the incorporation of zinc species promoted the primary aromatization by enhancing the dehydroaromatization and suppressing the cracking and subsequent H-transfer reaction. Furthermore, the addition of Ni species well inhibited the loss of zinc species by converting partial ZnO species to ZnOH;species, and thus improved the aromatization activity and catalyst stability. The catalytic performance results showed that the NZ3 possess higher conversion of methanol in a longer time and lower average rate of coke formation compared with NZ2. In addition,the NZ3 also exhibited the highest yield of BTX as the reaction proceeds.

Controllably tailoring external surface sites of nanosheet HZSM-5 for maximizing light olefins in catalytic cracking of n-decane

A series of triphenylethoxysilane(TPEOS)-modified nanosheet HZSM-5 catalysts(ZN-x,x=4%,8%and16%,mass)were synthesized by chemical liquid deposition to selectively change external acidity distributions.TPEOS modification was found to passivate some external Br?nsted and Lewis acid sites by37.8%,in which Br?nsted acid sites(BAS)were found more easily sacrificed by breaking the surface Al AO bond of bridging hydroxyl groups and forming Si AOASi bonds.The selectivity of ZN-8 catalyst for light olefins(ethylene,propylene and butene)in n-decane catalytic cracking is up to 26%(450℃,WHSV=10.95 h^(-1)),which is ca.78%higher than that of parent one.The better performance was attributed to the appropriate external acid density in ZN-8,which inhibits bimolecular hydrogen transfer reaction of light olefins on the adjacent acid sites,resulting in more olefins,few coke precursors and thus an excellent catalytic stability.

Effects of total replacement of corn silage with sorghum silage on milk yield,composition, and quality

Background： In the last years, difficulties occurring in corn cultivation（i.e., groundwater shortages, mycotoxin contamination） have been forcing dairy farmers to consider alternative silages. Some experiments conducted on lactating cows have proven that the total replacement of corn silage with sorghum silage did not reduce milk yield.However, this kind of substitution involves supplementing sorghum-based diets with grains, to compensate for the lower starch content of sorghum silage compared to corn silage. Change of silage type and inclusion of starch sources in the diet would influence rumen fermentations, with possible effects on milk composition（i.e., fatty acid profile） and coagulation properties. A worsening of milk coagulation properties would have a negative economic impact in Italy, where most of the milk produced is processed into cheese.This study was designed to compare milk composition and quality, with emphasis on fatty acid profile and coagulation properties, in dairy cows fed two diets based on corn or sorghum silage.Results： The sorghum diet reduced milk yield（P = 0.043） but not 4% fat corrected milk（P = 0.85）. Feeding sorghum silage did not influence milk contents of protein（P = 0.07） and lactose（P = 0.65）, and increased fat content（P = 0.024）.No differences emerged for milk concentrations of saturated（P = 0.61） and monounsaturated fatty acids（P = 0.50）,whereas polyunsaturated fatty acids were lower（P 〈 0.001） for the sorghum diet. Concentrations of n-6（P 〈 0.001） and n-3 fatty acids（P = 0.017） were lower in milk of cows fed the sorghum diet. Milk coagulation properties did not differ between the two diets, except the ＂a30＂（the curd firmness, expressed in mm, 30 min after rennet addition）, that was lower（P = 0.042） for the sorghum diet.Conclusions： Feeding a forage sorghum silage, properly supplemented with corn meal, as total replacement of corn silage maintained milk composition and did not influence negatively milk coagulation properties, which have a great economic relevance for the Italian dairy industry. Thus, silages obtained from forage sorghums could have a potential as substitute of corn silages in dairy cow diets.

Molecular Structure and Theoretical Thermodynamic Study of Folic Acid Based on the Computational Approach

In our previous work, we studied the interaction of folic acid, FA, molecule with single- walled carbon nanotube and the related binding energies with other related parameters. Now, in order to extend our study with respect to the other structural properties of folic acid molecule and its thermodynamic properties, we optimized the structures of both neutral and zwitteronic forms of this molecule by using the DFT/B3LYP method in the gas phase and then in different solvents. In addition, the electronic properties, such as the molecular orbital study （HOMO, LUMO, PDOS, and TDOS） and geometrical structure, were investigated by the above-mentioned method with 6-3 l G（d） basis set. The thermodynamic properties of both neutral and zwitterionic forms of the FA molecule at different temperature have been calculated. Natural bond orbital （NBO） analysis has been done to study the stability of the molecule arising from charge delocalization.

Synthesis,Structure and Photoluminescence of a New Pb(Ⅱ)Coordination Polymer[Pb(1,4-chdc)(L)]n·nH2O Based on a Flexible 1,4-Cyclohexanedicarboxylic Acid

A new Pb（Ⅱ） coordination polymer, [Pb（1,4-chdc）（L）]_n·nH_2O（1）, was synthesized under hydrothermal condition（1,4-H2 chdc = 1,4-cyclohexanedicarboxylic acid and L = 2-（3-fluorophenyl）-1H-imidazo[4,5-f][1,10]phenanthroline）. Its crystal structure was determined by singlecrystal X-ray diffraction. Compound 1 crystallizes in triclinic, space group P1 with a = 9.1182（8）, b = 11.3249（10）, c = 12.7326（12） A, α = 77.897（2）, β = 81.644（2）, γ = 84.491（2）°, V = 1269.0（2） A^3, Z = 2, C_（27）H_（24）FN_4O_5Pb, M_r = 710.69, D_c = 1.860 g/cm^3, F（000） = 690, μ（MoKa） = 6.701 mm^（-1）, R = 0.0349 and wR = 0.0746. In 1, each 1,4-chdc anion bridges two neighboring Pb（Ⅱ） atoms in a bidentate chelating coordination mode to give a chain structure. The L ligands are attached on one side of the chain through chelating the Pb（Ⅱ） atoms, and are stacked with those of an adjacent chain through π-π interactions, yielding a layer structure. The O-H···O and N-H···O hydrogen bonding interactions further stabilize the supramolecular layer structure of 1. Moreover, solid state luminescent property of 1 was also studied.

Two Metal Ion-controlled Zn(Ⅱ)/Cd(Ⅱ) Coordination Polymers Based on 1,3,5-Benzenetricarboxylic Acid

Two new coordination polymers {[Zn（Hbtc）（bpyb）]·H2O}n（1） and {[Cd（Hbtc）-（bpyb）（1.5）]·0.5 bpyb}n（2）（H3btc = 1,3,5-benzenetricarboxylic acid, bpyb = 1,4-bis（4-pyridyl）benzene） have been synthesized under hydrothermal conditions. The two compounds were characterized by elemental analysis, IR spectroscopy, and X-ray single-crystal diffraction. Compound 1 displays a 2-fold interpenetrating 3D supramolecular architecture through O–H…N/O hydrogen bonds and π-π stacking interactions. Compound 2 exhibits a 2D→3D polycatenated structure, which is further stabilized by O–H…N hydrogen bonds. The results indicate that the metal ion has significant effects on the formation and structure of the resulted coordination polymers. Furthermore, thermal stability and photoluminescent properties of 1 and 2 are also discussed in detail.

Solvothermal Synthesis,Crystal Structure and Photoluminescence Property of a 3D Lead(Ⅱ)Coordination Polymer Based on Terephthalic Acid

Solvothermal reaction of Pb（NO3）2·6H2O with rigid linear ligand terephthalic acid（H2pta） in N,N-dimethylformamide（DMF） produced a new three-dimensional（3D） lead（Ⅱ）coordination polymer[Pb2（pta）1.5（μ4-OH）（DMF）]n 1,and its structure was characterized by single-crystal X-ray diffraction analyses.In polymer 1,the μ4-OH bridges the nearby lead（Ⅱ） ions into an infinite one-dimensional（1D） chain,and then the organic ligand pta^2- joins the neighbored chains into a 3D structure by two similar connection modes in different configurations.The solid-state photoluminescent studies revealed that 1 exhibits a strong greenish emission mainly originating from ligand-to-metal charge transfer between the delocalized π bonds of the aromatic carboxylate ligand pta^2- and the p orbitals of the Pb^2＋ centers.

Synthesis and Characterization of a Two-dimensional Cadmium(Ⅱ) Metal Organic Framework with Fes Topology

A new Cd（II） coordination polymer, {[Cd（Hnbta）（L）]·H2O}n （L = 1,4-bis（5,6-dime- thylbenzimidazol-l-yl）butane）, H3nbta= 5-nitrobenzene-1,2,3-tricarboxylic acid）, has been hydro -thermally synthesized and characterized by elemental analyses, IR, XRPD, and single-crystal X-ray diffraction. The title compound crystallizes in the monoclinic system, space group P21/n with a = 17.3056（13）, b = 11.0114（9）, c = 17.7484（14） A,β= 117.3640（10）°, V = 3003.7（4） A3, Z = 4, C31H31CdN5O9, Mr = 730.01, Dc = 1.614 g/cm3, μ= 0.792 mm·-1and F（000） = 1488. The cadmium（II） ions are bridged by Hnbta2- to generate a two-dimensional metal organic framework with fes topology. In addition, the thermal stability and fluorescence properties of the complex were also studied.

Spectral,Thermal and Structural Studies of Two 3D Coordination Polymers Based on Tetracarboxylic Ligand

Two new coordination polymers,[M6L3（DMA）3（H2O）]（M=Zn for 1,Cu for 2,L=tetrakis[3-（carboxyphenyl）oxamethyl]methane acid,DMA = N,N-dimethylacetamide） have been solvothermally synthesized. Single-crystal X-ray diffraction analysis reveals that compounds 1 and 2 are isostructural and crystallize in the trigonal space group R. The asymmetrical unit contains two metal ions,one L^4- ligand and two coordinated DMA molecules. The metal ions are connected through six aromatic rings into a linear trimetallic zinc building unit. The whole structure is connected through tetrehedral ligand and the trimetallic building units to form a 4,6-connected framework of the toc topology. Compounds 1 and 2 are further studied by IR spectroscopy,thermogravimetric analyses and PXRD. The solid-state UV-Vis and photoluminescent properties of compounds 1 are also investigated.

A Pair of 3D Homochiral Coordination Polymers with Open Channels Constructed by Lactic Acid Derivative Ligands and In-situ Formed Anions

With the help of in-situ formed CH_3COO- anion, a pair of 3D homochiral coordination polymers with open channels were constructed by the assembly of lactic acid derivative ligands, 1.4-DIB ligands and Cd（II） ions, namely [Cd3（（R）-CIA）2（CH3CO2）_2（1.4-DIB）2（H2O）2]·x（Guest）（1-D） and [Cd3（（S）-CIA）2（CH3CO2）2（1.4-DIB）2（H2O）2]·x（Guest）（1-L）. They contain 1D interesting ladder-like Cd-（R）-CIA（3-） chains and exhibit SHG-active behavior and photoluminescent property.