新的聚苯乙烯负载锌化合物:高效苯酚氧化催化剂(英文)

The novel recyclable free –ONNO– tetradentate Schiff base ligand N,N′‐bis(2‐hydroxy‐3‐ methox‐ybenzaldehyde)4‐methylbenzene‐1,2‐diamine (3‐MOBdMBn) was synthesized. Complexation of this ligand with zinc(3‐MOBdMBn‐Zn) was performed, and the catalytic activity of the complex was evaluated. The polymer‐supported analog of this complex(P‐3‐MOBdMBn‐Zn) was synthesized, and its catalytic activity was studied. These free and polymer‐anchored zinc complexes were prepared by the reactions of metal solutions with one molar equivalent of unsupported 3‐MOBdMBn or P‐3‐MOBdMBn in methanol under nitrogen. The catalytic activity of 3‐MOBdMBn‐Zn and P‐3‐MOBdMBn‐Zn was evaluated in phenol oxidation. The activity of P‐3‐MOBdMBn‐Zn was signif‐icantly affected by the polymer support, and the rate of phenol conversion was around 50% for polystyrene‐supported 3‐MOBdMBn. The experimental results indicated that the reaction rate was affected by the polymer support, and the rate of phenol conversion was 1.64 μmol/(L·s) in the presence of polystyrene‐supported 3‐MOBdMBn.     

SYNTHESIS, CHARACTERIZATION AND CATALYTIC ACTIVITY OF N,N‘-BIS(3-ALLYL SALICYLIDENE)ETHYLENEDIAMINE COBALT(II) SCHIFF BASE COMPLEX ANCHORED ON A NEW POLYMER SUPPORT

A new chelating polymer support has been prepared by suspension copolymeriz a tion of synthesized N,N‘-bis(3-allyl salicylidene)ethylenediamine monomer Schiff base (N,N‘-BSEDA) with styrene (St) and divinylbenzene (DVB) using azobisisobutyronitrile (AIBN) as initiator in the presence of poly(vinyl alcohol). The content and complexation ability of monomer Schiff base (N,N‘-BSEDA) for cobalt(II) ions in prepared crosslinked polymer beads have shown dependence on the amount of DVB used in reaction mixture. The amount of monomer Schiff base (N,N‘-BSEDA) in crosslinked beads showed a substantial decreasing trend at high concentration of DVB in the reaction mixture (＞ 1.5 mol dm-3), hence the efficiency of complexation (EC%) and cobalt(II) ion loading (EL%) of polymer beads showed a decreasing trend. The structure of monomer Schiff base (N,N‘-BSEDA) and its cobalt(II) complex on polymer support was elucidated by IR, UV and magnetic measurements. The catalytic activity of polymer bound cobalt(Ⅱ) Schiff base complex was evaluated by analyzing kinetic data of decomposition of hydrogen peroxide in the presence of either supported cobalt (II) complex or free cobalt(II) complex. The activation energy for the decomposition of hydrogen peroxide by polymer supported cobalt(II)complex was found to be low (33.37 kJ mol-l) in comparison with unsupported cobalt(II) complex (56.35 kJ mol-1). On the basis of experimental observations, reaction steps are proposed and a suitable rate expression derived.     

可磁性回收纳米级负载型杂多酸催化剂用于水中生物活性化合物的绿色合成(英文)

12‐Tungstophosphoric acid supported on aerosil silica and silica‐coated γ‐Fe2O3 nanoparticles was prepared and characterized using transmission electron microscopy,scanning electron microscopy,and inductively coupled plasma atomic emission spectroscopy.The catalytic activity of the two prepared catalysts was compared in the synthesis of 1,8‐dioxo‐9,10‐diaryldecahydroacridines in water.12‐Tungstophosphoric acid was highly dispersed on the silica‐coated γ‐Fe2O3 nanoparticles and showed higher activity and a higher reuse number compared with the acid supported on aerosil silica.The catalyst could be recovered simply by using an external magnetic field and could be reused several times without appreciable loss of its catalytic activity.     

MgO纳米晶负载镍催化剂用于甲烷蒸汽重整反应(英文)

Nanocrystalline MgO with a relatively high surface area and mesoporous structure was synthesized by a surfactant assisted precipitation method for use as the support of nickel catalysts for steam reforming of methane. The samples were characterized by X‐ray diffraction, N2 adsorption, temperature‐programmed reduction, temperature‐programmed oxidation, scanning electron microscopy, and transmission electron microscopy. The catalysts showed high catalytic activity and good stability in the steam reforming of methane. Increasing the nickel loading up to 10 wt% gave increased activity. Catalysts with higher nickel loadings showed more deposited carbon after reaction. The excellent anti‐coking performance of the catalysts was attributed to the formation of a nickel‐magnesia solid solution, basicity of the support surface, and nickel‐support interaction.     

Preparation of microcapsule-supported palladium catalyst using SPG (Shirasu Porous Glass) emulsification technique

<正>A new method for the preparation of microcapsule-supported palladium catalyst was described.The highly monodisperse crosslinked polystyrene microcapsules containing phosphine ligand were synthesized by the self-assembling of phase separated polymer (SaPSeP) method using diphenyl(4-vinylphenyl) phosphine and divinylbenzene as a monomer and crosslinking agent,respectively, and 2,2'-azobisisobutyronitrile(AIBN) as an initiator within the droplets of oil-in-water(O/W) emulsions,which were prepared by using the Shirasu Porous Glass(SPG) membrane emulsification technique.The prepared microcapsule-supported palladium catalyst exhibited high catalytic activity for Heck reaction and can be reused several times without loss of activity.     

Catalytic abatement of CO and volatile organic compounds in waste gases by gold catalysts supported on ceria-modified mesoporous titania and zirconia

Mesoporous oxides TiO2 and ZrO2, synthesized by surfactant templating via a neutral C13(EO)6–Zr(OC3H7)4 assembly pathway, and ceria‐modified TiO2 and ZrO2, prepared by a deposi‐tion–precipitation (DP) method, featuring high surface areas and uniform pore size distributions were used as supports for gold catalysts. The supported gold catalysts were assessed for the cata‐lytic abatement of air pollutants, i.e., CO, CH3OH, and (CH3)2O. The gold was supported on the mes‐oporous oxides by a DP method. The supports and catalysts were characterized by powder X‐ray diffraction, high‐resolution transmission electron microscopy, N2 adsorption–desorption analysis, and temperature‐programmed reduction technique. A high degree of synergistic interaction be‐tween ceria and mesoporous ZrO2 and TiO2 as well as a positive modification of the structural and catalytic properties by ceria was observed. The ceria additive interacts with the mesoporous oxides and induces a strong effect on the reducibility of the supports. The catalytic behavior of the catalysts was discussed to determine the role of the ceria modifying additive and possible interaction be‐tween the gold nanoparticles and ceria‐mesoporous oxide supports. The gold catalysts supported on ceria‐modified mesoporous ZrO2 displayed superior catalytic activity (~100%conversion of CO at 10 °C and CH3OH at 60 °C). The high catalytic activity can be attributed to the ability of the sup‐port to assist oxygen vacancies formation. The studies indicate that the ceria‐modified mesoporous oxide supports have potential as supports for gold‐based catalysts.     

Polystyrene-supported Phenol/DMAP： an Efficient Binary Catalyst System for CO2 Fixation to Give Cyclic Carbonates

Polystyrene-supported phenol （PS-PhOH） was successfully synthesized by alkylation reaction of phenol with 2% DVB cross-linked chloromethylated polystyrene and characterized by IR spectra and elemental analysis. In conjunction with an organic base such as DMAP, DBU, triethylamine （Et3N）, diethylamine （Et2NH） or pyridine, the PS-PhOH could effectively catalyze the coupling reaction of carbon dioxide with epoxides to give cyclic carbonates in high yield and selectivity under mild conditions. The binary catalyst system of the PS-PhOH/DMAP was found to be the most active. The influence of reaction temperature, carbon dioxide pressure and reaction time on the yield of product was carefully investigated. The PS-PhOH could be recycled by simple filtration for at least up to ten times without loss of catalytic activity.     

Ligninolytic Peroxidase-Like Activity of a Synthetic Metalloporphine Immobilized onto Mercapto-Grafted Crosslinked PVA Inspired by the Active Site of Cytochrome P450

A synthetic metalloporphine was immobilized onto a PVA-based and mercapto-grafted solid support, emulating the active site of cytochrome P450. Its ligninolytic peroxidase-like catalytic activity was studied. The coordinated mercapto ligand significantly affected the catalytic features of the catalyst because the oxidation of lignin-model compounds was very slow by comparison with imidazoleand pyridine-coordinated immobilized metalloporphines. Conversely, the catalyst efficiently bleached several industrial dyes and thus demonstrated promising activity for this application. Based on this altered substrate specificity the oxygen-donor catalytic route seems to be more favorable than a single electron oxidation pathway.     

茚基镍的卤化物/四苯硼钠/三苯基膦体系催化苯乙烯聚合

The catalytic activity of a series of indenylnickel（Ⅱ） halides： （1-R-Ind）Ni（PPh3）X （R=ethyl, cyclopentyl and benzyl, while X=Cl, Br and I）, towards styrene polymerization was studied in the presence of NaBPh4 and PPh3. The catalytic property of these halides was related to the substituent group on the indenyl ligand and the halogen atom bonded to the metal atom. Among them, the （1-Et-Ind）Ni（PPh3）Cl/NaBPha/PPh3 system showed the highest activity for the polymerization of styrene, and the polystyrene obtained was a syndio-rich （rr triad） atactic polymer with Mn values in the range of 103--104. The mechanism of the styrene polymerization initiated by the （1-Et-Ind）Ni（PPh3）Cl/NaBPha/PPh3 system was studied.     

Synthesis,Crystal Structure and Biological Properties of One Zinc(Ⅱ) Complex Based on 4-Acyl Pyrazolone Derivative

[Zn(L)(CH3OH)3](H2L = N-(1-phenyl-3-methyl-4-propenylidene-5-pyrazolone)-salicylidene hydrazide) has been synthesized by the reaction of zinc nitrate and ligand H2 L. The complex crystallizes in orthorhombic system, space group Pbca with a = 5.888(15), b = 14.564(14), c = 22.20(2) , V = 5137(8) 3, Z = 8 and F(000) = 2184. The ligand serves as a negative bivalent tridentate chelating agent to coordinate with the central zinc(II) atom. DNA-binding was studied by UV-Vis spectral analysis and ethidium bromide(EB) displacement experiments. The results showed that the DNA-binding constant of the complex is 5.1×104 M–1. Antitumor activity of [Zn(L)(CH3OH)3] and the ligand have been investigated by MTT assay, which indicated that the complex has better cytotoxicity to Eca-109 and He La than free ligand.     

A Novel Carbon Nanotube-Supported NiP Amorphous Alloy Catalyst and Its Hydrogenation Activity

A carbon nanotube-supported NiP amorphous catalyst (NiP/CNT) was prepared by induced reduction. Benzene hydrogenation was used as a probe reaction for the study of catalytic activity. The effects of the support on the activity and thermal stability of the supported catalyst were discussed based on various characterizations, including XRD, TEM, ICP, XPS, H2-TPD, and DTA. In comparison with the NiP amorphous alloy, the benzene conversion on NiP/CNT catalyst was lower, but the specific activity of NiP/CNT was higher, which is attributed to the dispersion produced by the support, an electron-donating effect, and the hydrogen-storage ability of CNT. The NiP/CNT thermal stability was improved because of the dispersion and electronic effects and the good heat-conduction ability of the CNT support.     

Studies on the Performance and Structure of Supported Catalysts for the Partial Oxidation of Methane to Syngas

The catalytic properties of several supported metal catalysts on different carriers were studied in the partial oxidation of methane (POM) to syngas. In our experiment, supported noble metal catalysts exhibited better performance than the other supported transition metal catalysts. The catalyst performances were significantly influenced by the d-electron configuration of the active metal components and the dispersion of active metal components on the support. A catalyst with a moderate number of unpaired electrons in the d-orbital of the active metal support without obvious acidity or redox activity (e.g. MgO) was suitable for POM performance. The Rh/SiO2 catalyst was the best in the POM reaction, among those investigated. Reaction conditions apparently also affected the POM performance of the catalyst. The conversion of methane and the selectivity for CO increased with the reaction temperature, and a high CH4/O2 ratio was not beneficial for POM performance.     

Catalytic Kinetics of the Schiff Base Metal Complexes Bearing Side Chain of Cyclic morpholine in Carboxylic Ester Hydrolysis

It has been reported that two Schiff base transition metal complexes bearing the side chain of the morpholine ring were synthesized and characterized, and two complexes with the same base agent but different metal ions were used as a simulant hydrolase in the catalytic hydrolysis of p-nitrophenyl picolinate in this paper. The mechanism of PNPP catalytic hydrolysis is proposed and supported by the results of the spectral analysis and the kinetic calculation. A kinetic mathematical model, applied to the calculation of the kinetic and thermodynamics parameters of PNPP catalytic hydrolysis, has been established on the foundation of the mechanism proposed. The result of the study shows that the two complexes have a good catalytic activity in PNPP catalytic hydrolysis, and the rate of the PNPP catalytic hydrolysis was increased with the increase of the pH values in the buffer solution and affected by the polarization effect of metal ion of the complexes.     

PREPARATION AND CATALYTIC BEHAVIOUR OF POLYMER-BOUND METALLOPORPHYRIN IN HYDROGENATION OF OLEFIN

The meso- tetraarylporphyrin has been anchored to styrene- divinylbenzenecopolymers by reaction of meso- tetra (4-hydroxylphenyl ) porphyrin with chloromethylatedresin under mild condition. A number of polymer transition metal complexes have beenprepared with the polymer ligand and metal salts. The polymeric ligand and its complexeshave been characterized by electronic spectra, and vibrational spectra. Cyclohexene can behydrogenated with the polymeric porphyrin palladium complex(P-THPPPd) as catalyst,and its catalytic activity was influenced by the polarity of solvents, the contents of water inethanol or reaction temperature. However, its catalytic activity was lower for nitro groups,carbonyl groups and olefins with steric hindrance substituents, and showed no activity foraromatic rings under these conditions.     

Partial amination of cationic exchange resins and its application in the hydration of butene

In this work,the amination of sulfonated polystyrene resin with alkyl secondary amine is investigated.The catalytic activities of the modified resins are determined through the hydration of 1-butene.The optimum chain length and the best range of amination rate are determined.It is found that the single-pass conversion of 1-butene was raised 2% on average,and the relative activity was increased over 30% after modification.A hypothesis about the enhancement of catalytic activities by the inclusion of alkyl chain to wrap up the butene molecule is proposed.     

酶法合成头孢克罗

Enzymatic synthesis of cefaclor from 7-aminodesacetoxymethyl-3-chlorocephalosporainc acid(6-ACCA) and phenylglycine derivatives using penicillin G acylase was studied .Many factors that affect the conversion of 7-ACCA to cefaclor were examined.The immobilized enzyme from Bacillis megaterium gave a better catalytic properties and the higher conversion was obtained using phenylglycine methyl ester(PGME) as acyl donor.And the external mass transfer limitation could be eliminated when the stirring rate was more than 150r/min.Low temperature was beneficial for the synthesis and the results showed that the synthetase activity was hardly influenced by temperature while the amidase activity was affected greatly by temperature.The optimum reaction conditions were determined at pH 6.5 and 10℃,respectively.The best 7-ACCA conversion of 56% was achieved when the intial concentration of 7-ACCA and PGME was at 50 mM and 150mM,respectively.     

Multi-walled carbon nanotubes as a ligand in nickel α-diimine based ethylene polymerization

Two novel heterogeneous nickel ?-diimine based polymerization catalysts, containing MWCNT as the main ligand, were synthesized by novel in situ catalyst preparation technique. The in situ synthesis was performed by covalent attachment of the acenaphthenic ligand core to amine functionalized MWCNT ligand arms through diimine bonding and further nickel dibromide chelation. The prepared catalysts were fully characterized and their structures and supporting efficiencies were determined. Single or double introduction of the MWCNTs through their ends or sidewall(s) in the catalytic system, as a ligand, influenced the catalytic performance, microstructure and morphology of obtained polyethylenes. MWCNT sidewall bonding to para-aryl position of the tetramethylphenyl moiety performed as more electron-donating ligand than MWCNT ends linked to the imine bond and protected the catalytic system to retain its activity. This character resulted in the maintenance of the resulting polymer topology at elevated temperatures so that the catalytic activity and the obtained polymer melting points remained around 110 g PE?mmol?1 Ni?h?1 and 123 ℃ in all polymerization temperatures respectively. In polymerization trials, molecular weight fall against temperature was not as sharp as what had been observed in sequentially prepared catalysts insofar as the molecular weight of resultant polymer at 60 ℃ reached to 310000 g?mol?1 which was close to the highest value had been reported at 30 ℃ for sequentially prepared catalysts. TEM observations showed the presence of the stopped-growth polymer chains due to geometrical constrains or ligand debonding for both catalytic systems.     

Synthesis of porous hematite nanorods loaded with CuO nanocrystals as catalysts for CO oxidation

Porous hematite (α-Fe2O3) nanorods with the diameter of 20-40 nm and the length of 80-300 nm were synthesized by a simple surfactant-assisted method in the presence of cetyltrimethylammonium bromide (CTAB).The α-Fe2O3 nanorods possess a mesostructure with a pore size distribution in the range of 5-12 nm and high surface area,exhibiting high catalytic activity for CO oxidation.CuO nanocrystals were loaded on the surface of porous α-Fe2O3 nanorods by a deposition-precipitation method,and the catalysts exhibited superior activity for catalytic oxidation of CO,as compared with commercial α-Fe2O3 powders supported CuO catalyst.The enhanced catalytic activity was attributed to the strong interaction between the CuO nanocrystals and the support of porous α-Fe2O3 nanorods.     

Autothermal reforming of methane over Ni catalysts supported over ZrO2-CeO2-Al2O3

Ni catalysts supported on Al2O3, ZrO2-Al2O3, CeO2-Al2O3 and ZrO2-CeO2-Al2O3 were prepared by coprecipitation method, and their catalytic performances for autothermal reforming of methane to hydrogen were investigated. The Ni-supported catalysts were characterized by XRD, TPR and XPS. The relationship between the structures and catalytic activities of the catalysts was discussed. The results showed that the catalytic activity and stability of the Ni/ZrO2-CeO2-Al2O3 catalyst was better than those of other catalysts with the highest CH4 conversion, H2/CO and H2/COx ratio at 750 ℃. The catalyst showed a little deactivation along the reaction time during its 72 h on stream with the mean deactivation rate of 0.08%/h. The catalytic performance of the Ni/ZrO2-CeO2-Al2O3 catalyst was also affected by reaction temperature, no2 ： nCH4 molar ratio and nH2O ： nCH4 molar ratio. TPR, XRD and XPS measurements indicated that the formation of ZrO2-CeO2 solid solution could improve the dispersion of NiO, and inhibit the formation of NiAl2O3, and thus significantly promoted the catalytic activity of the Ni/ZrO2-CeO2-Al2O3 catalyst.     

聚合物固载化聚乙二醇季胺盐型相转移催化剂的结构与催化活性

The gelatinous and macroporous phase transfer catalysts with multiple active centers were synthesized by means of quarterisation of PEG tertiary amine and chloromethylated St DVB copolymer. They were examined as phase transfer catalysts in the reaction of n C 8H 17 Br with solid NaI. The experimental results showed that the reaction rate was first order with respect to the concentration of n C 8H 17 Br. The effects of catalyst structure on the catalytic activity were also investigated. The observed reaction rate constant ( k obsd ) increased as the degree of cross linking of polymer decreased. Macroporous catalysts showed a higher activity (2～2 5 times) than that of microporous catalysts with the same degree of cross linking of polymer, particle size and amount of supported PEG. Molecular weight of PEG also showed much influence on k obsd . As molecular weight of PEG rose properly, the catalysts showed a higher activity. The results were discussed from the aspect of triphase catalysis reaction mechanism.