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1.
在制备CuO/ZnO/Al2O3催化剂的老化过程中,采用微波辐射老化技术,着重研究了溶剂极性对前躯体物相组成,烧后CuO/ZnO/Al2O3催化剂结构及其在浆态床合成甲醇工艺中催化性能的影响。通过XRD、DTG、H2-TPR,FTIR、HR-TEM和XPS对前驱体及催化剂表征表明,沉淀母液在微波辐射条件下进行老化,溶剂的极性对前躯体物相组成及催化剂结构影响显著。随着溶剂极性的增大,Zn2+/Cu2+取代Cu2(CO3)(OH)2/Zn5(CO3)2(OH)6中Cu2+/Zn2+的取代反应增强,使得前躯体中(Cu,Zn)5(CO3)2(OH)6和(Cu,Zn)2(CO3)(OH)2物相的含量增多,结晶度提高,导致烧后CuO/ZnO/Al2O3催化剂中CuO-ZnO协同作用增强,且CuO晶粒减小,表面Cu含量增加,催化剂活性和稳定性提高。水溶剂的极性最大,制备的催化剂活性和稳定性最好,甲醇的时空收率(STY)和平均失活率分别为320 mg.g-1.h-1和0.11%.d-1。  相似文献   

2.
Absolute rate constants (keff) for the chemical reactions of Cu(II)2(3,5‐di‐iso‐propylsalicylate)4(H2O)3, Cu(II)2(3,5‐di‐tert‐butylsalicylate)4, Cu(II)2(3,5‐di‐tert‐butylsalicylate)4(H2O)4, Cu(II)2(3,5‐dimethylsalicylate)4(H2O)3, Cu(II)2(3‐ethylsalicylate)4(H2O), Cu(II)2(3‐phenylsalicylate)4, and Cu(II)(3,5‐di‐iso‐propylsalicylate)2(pyridine)2 with tert‐butylperoxyl radical were determined using kinetic electron paramagnetic resonance measurements in 10% toluene in the hexane medium at temperatures ranging from ?63°C to 2°C. These antioxidant (AO) chelates were ranked by their reactivity as follows: 2,6‐di‐tert‐butyl‐4‐methylphenol ? Cu(II)2(3,5‐di‐tert‐butylsalicylate)4 ? Cu(II)2(3‐phenylsalicylate)4 > Cu(II)2(3,5‐di‐iso‐propylsalicylate)4(H2O)3 ? Cu(II)2(3,5‐di‐tert‐butylsalicylate)4(H2O)4 ? Cu(II)2(3,5‐dimethylsalicylate)4(H2O)3 > Cu(II)2(3‐ethylsalicylate)4(H2O) ? Cu(II)(3,5‐di‐iso‐propylsalicylate)2(pyridine)2 at 20°C. Differential pulse voltammetry was used to determine redox behavior of these chelates in CH2Cl2. Two types of salicylic OH groups were detected in these Cu(II) salicylates, characterized by the presence or absence of AO reactivity. One of them was coordinate covalently bonded to Cu(II) via the oxygen atoms of the salicylic OH groups, displaying oxidation peak potentials in the range from +650 to 970 mV versus Ag/Ag+. The second type was intramolecularly hydrogen bonded to carboxylate oxygens, with an oxidation peak potential in the range from +1100 to 1200 mV versus Ag/Ag+. It was concluded that non–hydrogen‐bonded salicylic OH groups are responsible for the antiperoxyl radical reactivity of these chelates, while neither Cu(II) nor salicylate ligands displayed reactivity with peroxyl radical. It has been established in this research that axially bonded electron pair donors such as pyridine and water decrease H‐donating reactivity of Cu(II) salicylates by promoting the formation of intramolecular hydrogen bonding between the salicylic OH hydrogen atoms and carboxylate oxygen atoms in the salicylic ligands. Dependences of log keff at 20°C and the anodic oxidation potential (Epa) for the salicylic OH group on the difference between symmetric and asymmetric stretching frequencies of carboxylate groups (in Fourier transform infrared spectra) for the substituted Cu(II) salicylates were determined. © 2009 Wiley Periodicals, Inc. Int J Chem Kinet 42: 56–67, 2010  相似文献   

3.
One nonlinear and one linear trinuclear copper(II) complex [Cu3(dien)2(pdc)2CH3OH]2?·?6CH3OH (1) and [Cu3(pdc)2(CH3OH)6(H2O)4] (2) were prepared and characterized structurally, where dien is diethylenetriamine and pdc3? the trianion of 3,5-pyrazoledicarboxylic acid. Both complexes consist of 3,5-pyrazoledicarboxylato-bridged trinuclear copper(II) centers. In 1, copper(II) ions are five-coordinate in distorted square pyramids with bond angles 164.78° for Cu(1)–Cu(2)–Cu(3) and 164.51° for Cu(4)–Cu(5)–Cu(6). In 2, the three copper(II) ions are six-coordinate with elongated octahedral geometry. The trinuclear units of 1 and 2 interact through hydrogen bonds to form 3-D and 2-D supramolecular networks, respectively. Variable temperature magnetic susceptibility measurements show that 1 and 2 are antiferromagnetically coupled with J values of ?11.2 and ?13.3?cm?1.  相似文献   

4.
Abstract

In order to develop an easy and rapid identification method for distinguishing CH3OH from C2H5OH, a new carbonate-based trinuclear Cu(II) precursor, [Cu3(bpy)63-CO3)(CH3OH)](BF4)4·(CH3OH)2·(H2O)2 (1), has been isolated. We report here the synthesis, crystal structure, and characterizations by various spectroscopic (IR, UV–Vis, powder XRD) techniques, as well as the solvatochromic behavior of this coordination compound. Its X-ray crystal structure reveals that the main structure of 1 consists of three [(bpy)2Cu]2+ centers, which are bridged by carbonate via a μ3111 fashion. Strong O–H?O hydrogen bonding between the carbonate and solvent molecules has been observed for the first time in similar structures. Its ground powder exhibits solvatochromic behavior that selectively distinguishes CH3OH from C2H5OH.  相似文献   

5.
Four new solvent-induced Cu(II) complexes with the chemical formulae [{Cu(HL)(CH3OH)}2Cu] · CH3OH (1), [{(Cu(HL))2(CH3CH2OH)2}Cu] (2), [{CuL(H2O)}2Cu2] · 2CH3CH2CH2OH (3) and [{(Cu(HL))2(CH3CH2CH2CH2OH)2}Cu] (4), where H4L = 6,6′-dihydroxy-2,2′-[ethylenediyldioxybis(nitrilomethylidyne)]diphenol, have been synthesized and characterized by elemental analyses, 1H NMR, FT-IR, UV–Vis spectra, TG-DTA, molar conductances and X-ray crystallography. Complexes 1, 2 and 4 have an elongated square-pyramidal geometry with an unusually long bond from the penta-coordinated Cu(II) centres to the oxygen atoms of the apically coordinated solvent (methanol, ethanol or n-butanol) molecules for the terminal Cu(II) ions, and a square planar geometry distorted tetrahedrally for the central Cu(II) ion. In complex 3, the terminal Cu(II) ions have trigonal bipyramidal coordination geometries constituted by equatorial O2N donor sites, with one oxygen atom from one of the coordinated water molecules and one nitrogen atom from a completely deprotonated L4− ligand unit in the axial positions, and the central Cu(II) ions are in slightly tetrahedrally distorted square planar geometries constituted by four phenoxo oxygen donors from two completely deprotonated L4− ligand units, and these form a tetrametal Cu–O–Cu–O–Cu–O–Cu–O eight-membered ring. These four complexes exhibit strong hydrogen bonding interactions in the solid state. Moreover, co-crystallizing n-propanol molecules link two other adjacent complex molecules into a self-assembled infinite 2D supramolecular structure via the intermolecular hydrogen bonds in complex 3.  相似文献   

6.
Poly(acrylonitrile-methylmethacrylate-sodium vinylsulfonate) membranes were subjected to seven different chemical modifications and the amount of the newly formed groups was measured for each membrane. Urease was then covalently immobilized onto the modified membranes and the amount of bound protein was determined. The kinetic parameters V(max) and K(m) of the immobilized urease were studied under static and dynamic conditions. Results showed that the rate of the enzyme reaction was higher for the membranes modified with NH(2)OH . H(2)SO(4), NH(2)NH(2) . H(2)SO(4), NaOH + EDA and NaOH + GA + EDA. It was confirmed that the reaction rate, measured under dynamic conditions, was higher than that one determined under static conditions. The influence of Cu(II) ions, as inhibitors, on the enzyme reaction kinetics (V(i) and K(i)) was also investigated. It turned out that the most sensitive membranes towards Cu(II) were those modified with NH(2)NH(2) . H(2)SO(4), NaOH + EDA and H(2)O(2). The results initiated further investigations on the influence of other heavy metal ions (Cd(II), Zn(II), Ni(II) and Pb(II)) over urease bound to a NH(2)OH . H(2)SO(4)-modified membrane. It was found that the inhibition effect of the heavy metal ions over immobilized urease decreases in the order: Cu(II) > Cd(II) > Zn(II) > Ni(II) > Pb(II). [Diagram: see text]  相似文献   

7.
A platinum-lined, flowing autoclave facility is used to investigate the solubility behavior of copper(II) oxide (CuO) in aqueous sodium phosphate solutions at temperatures between 19 and 262°C. Copper solubilities are observed to increase continuously with temperature and phosphate concentration. The measured solubility behavior is examined via a Cu(II) ion hydrolysis/complexing model and thermodynamic functions for the hydrolysis/complexing reactions are obtained from a leastsquares analysis of the data. Altogether, thermochemical properties are established for five anionic complexes: Cu(OH) 3 , Cu(OH) 4 2– , Cu(OH) 2 (HPO 4 ) 2– , Cu(OH) 3 (H 2 PO 4 ) 2– , and Cu(OH) 2 (PO 4 ) 3– . Precise thermochemical parameters are also derived for the Cu(OH)+ hydroxocomplex based on CuO solubility behavior previously observed (Ref. 3) for pure water at elevated temperatures. The relative ease of Cu(II) ion hydrolysis is such that Cu(OH) 3 species become the preferred hydroxocomplex for pH9.4.Prepared for presentation at the Fourth International Symposium on solubility Phenomena, Rensselaer Polytechnic Institute, August 1990.  相似文献   

8.
The complexes of thiosemicarbazide (HTS) have been prepared and characterized by spectral, thermal and magnetic studies. The deprotonation constant of HTS and the formation constants of its complexes were evaluated pH-metrically. The Cu(II) acetate-HTS system gave high stability. The catalytic activity of Co(II), Ni(II) and Cu(II) complexes was tested to decompose H2O2. The Co(II) complex has no activity whereas the Cu(II) complex was found to be more active than Ni(II). The different Cu(II) complexes were tested; [Cu2(TS)(OH)2(OAc)] was highly active. All parameters affecting the reaction rate (concentration of H2O2, weight of catalyst, temperature and pH) were studied and the optimum conditions were evaluated. Attempts to increase the activity of [Cu2(TS)(HO)2(OAc)] by mixing with superconducting cuprate sample, Nd0.1Y0.9Ba2Cu3O7-δ, will be the subject of further studies.  相似文献   

9.
Self assembly of N-salicylidene 2-aminopyridine (L1H) with Cu(NO3)2·3H2O affords [Cu4(L1)4(NO3)3(CH3OH)][Cu(L1)(NO3)2](2-aminopyridinium)(NO3)·5CH3OH (1) which is composed of an asymmetric [2 × 2] grid-like cationic complex that co-crystallizes with a Cu(II) mononuclear anion. This remarkable tetranuclear unit presents three penta-coordinated and one hexa-coordinated Cu(II) sites. This quadruple helicate structure reveals strong anti-ferromagnetic coupling (J = −340(2) cm−1) between Cu(II) ions through a double alkoxo bridge. Reacting L1H with Cu(NO3)2·3H2O in slightly different conditions affords however a more symmetric tetranuclear grid-like complex: [Cu4(L1)4(NO3)2(OH)2](2-aminopyridinium)(OH)·CH3OH) (2). A dinuclear Ni(II) complex, [Ni2(L2)2(L2H)2(NCS)2(CH3OH)2]·2CH3OH (3), obtained with another related donor ligand (L2H N-salicylidene 3-aminomethylpyridine) was also prepared.  相似文献   

10.
A rapid and efficient method for the synthesis of 2-imidazolines and their N-hydroxyethyl derivatives from the reaction of aromatic nitriles with ethylenediamine (EDA) or N-(2-aminoethyl)ethanolamine (AEEA) using cupric indole-3-acetate (Cu(II)-(IAA)2) as a reusable catalyst under reflux and microwave conditions is reported. And seven new N-hydroxyethyl-imidazolines were reported for the first time.  相似文献   

11.
Treatment of [Cu(pcho)2(NCMe)][BF4] 1 (pcho = 2‐(diphenylphosphino)benzaldehyde) with aqueous H2O2 in THF solvent affords [Cu2(dpb)2(THF)2(H2O)2] [BF4]2 2 (dpb = 2‐(diphenylphosphinoxide)‐benzoate) after crystallization from diethyl ether. This reaction involves oxidation of Cu(I) to Cu(II) ion, phosphine to phosphinoxide, and benzaldehyde to benzoate species. The crystal structure of 2 consists of two copper(II) atoms bridged by two carboxylate moieties of the dpb ligands. The coordination about each copper(II) atom is a distorted trigonal bipyramid.  相似文献   

12.
Pyridine-2-carbonitrile (2-CNpy) undergoes Cu(II) or Co(II)-promoted hydrolysis to pyridine-2-carboxamide (piaH) and/or pyridine-2-carboxylic acid (pycH). The pathway of pycH formation depends on the presence of 2-amino-2-hydroxymethyl-1,3-propanediol (AL1) and on the central atom. In the absence of AL1, Co(II) or Cu(II) ions mediate piaH formation under mild reaction conditions in the first hydrolytic step. Cu(II) ions assist in piaH transformation to pycH by subsequent reflux. In the presence of AL1 and Co(II), a Co(II) complex containing pyoxaL1 (2-(2-pyridinyl)-4,4-bis(hydroxymethyl)-2-oxazoline) is formed in the first stage; subsequent decomposition of pyoxaL1 under the reflux yields pycH. Under similar conditions, no solid Cu(II) complex with pyoxaL1 can be isolated, but a Cu(II) complex with coordinated pyc anions precipitates from the reaction mixture. The synthesis, spectral and magnetic properties of the complexes [Co(H2O)2 (piaH)2]Cl2, [Co(H2O)2(pyc)2] · 2H2O, [Cu(H2O)2(piaH)2]Cl2, [Cu(pyc)2] and [Cu(pyc)2] · 2H2O, including the structure determination of the latter one, are described.  相似文献   

13.
Depending on the ethanol-water ratio, five individual compounds of copper(II) of the following compositions are formed in the CuCl2-C2H5OH-H2O system: [CuCl2(C2H5OH)4] (I), cis-[CuCl2(C2H5OH)2·(H2O)2] (II), trans-[CuCl2(C2H5OH)2· (H2O)2](III), [Cu(H2O)6]2+ (IV), and [Cu(OH)2(H2O)4] (V).Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2725–2729, December, 1990.  相似文献   

14.
The title compound, poly[[μ‐cyanoureato‐tri‐μ‐hydroxido‐dicopper(II)] dihydrate], {[Cu2(C2H2N3O)(OH)3]·2H2O}n, is a new layered copper(II) hydroxide salt (LHS) with cyanoureate ions and water molecules in the interlayer space. The three distinct copper(II) ions have distorted octahedral geometry: one Cu (symmetry ) is coordinated to six hydroxide groups (4OH + 2OH), whilst the other two Cu atoms (symmetries and 1) are coordinated to four hydroxides and two N atoms from nitrile groups of the cyanoureate ions (4OH + 2N). The structure is held together by hydrogen‐bonding interactions between the terminal –NH2 groups and the central cyanamide N atoms of organic anions associated with neighbouring layers.  相似文献   

15.
Mn(II), Fe(III), Co(II), Ni(II), Cu(II) and Zn(II) complexes of multifunctional triaminoxime have been synthesized and characterized by elemental analyses, IR, UV–Vis spectra, magnetic moments, 1H- and 13C-NMR spectra for ligand and its Ni(II) complex, mass spectra, molar conductances, thermal analyses (DTA, DTG and TG) and ESR measurements. The IR spectral data show that the ligand is bi-basic or tri-basic tetradentate towards the metals. Molar conductances in DMF indicate that the complexes are non-electrolytes. The ESR spectra of solid copper(II) complexes [(HL)(Cu)2(Cl)2] · 2H2O (2) and [(L)(Cu)3(OH)3(H2O)6] · 7H2O (6) show axial symmetry of a d x²???y 2 ground state; however, [(HL)(Co)] (4) shows an axial type with d Z 2 ground state and manganese(II) complex [(L)(Mn)3(OH)3(H2O)6] · 4H2O (10) shows an isotropic type. The biological activity of the ligand and its metal complexes are discussed.  相似文献   

16.
在微波辐射条件下,对CuO/ZnO/Al2O3催化剂的沉淀母液进行老化,通过XRD、TG、H2-TPR,FTIR、HR-TEM和XPS对前驱体及催化剂微观结构的进行表征,探讨了CuO/ZnO/Al2O3催化剂前驱体晶相转变过程中微波辐射的作用。结果表明,微波辐射有利于Cu2+取代Zn5(CO3)2(OH)6中Zn2+的同晶取代反应。微波辐射的老化过程中,首先发生Cu2+取代Zn5(CO3)2(OH)6中Zn2+生成(Cu,Zn)5(CO3)2(OH)6的同晶取代反应,并于1.0 h内基本完成;随着老化时间继续延长,主要进行Zn2+取代Cu2(CO3)(OH)2中Cu2+生成(Cu,Zn)2(CO3)(OH)2的同晶取代反应,同时(Cu,Zn)5(CO3)2(OH)6进一步结晶。与常规老化1 h制备的前驱体相比,微波辐射老化1.0 h制备的前驱体含有较多的(Cu,Zn)5(CO3)2(OH)6物相,有助于增强焙烧后CuO/ZnO/Al2O3催化剂中CuO-ZnO协同作用,提高表面铜含量,进而提高CuO/ZnO/Al2O3催化剂在浆态床合成甲醇的催化活性和稳定性,在400 h浆态床合成甲醇评价期间,甲醇时空收率最大达318.9 g.kg-1.h-1,失活率仅为0.11%.d-1。  相似文献   

17.
Summary The stabilities of rosasite, (Cu, Zn)2 (CO3)(OH)2, and aurichalcite, (Zn, Cu)5(CO3)2(OH)6, have been determined by solution experiments with computer calculations of aqueous species in equilibrium with the solid phases. G f o values for rosasite and aurichalcite have been calculated as –1100 and –2766 kJ mol–1 respectively for specific samples of the two minerals. Most of the difference between the free energies of the compounds and those of malachite, Cu2(CO3)(OH)2, and hydrozincite, Zn5(CO3)2(OH)6 arises from substitution of the minor cation in the crystal lattice. Malachite, zincian malachite and rosasite should be considered as a single isomorphous series.Part II: A. K. Alwan and P. A. Williams,Transition Acct. Chem., 4, 319 (1979).  相似文献   

18.
The thermal behaviors of [1,1,1-trifluro-3-(2-thenoyl)-acetonato]copper(II) Cu(TTA)2 and its adducts with pyridine Cu(TTA)2(Py)2, 2,2'-bipyridine Cu(TTA)2(Bpy), quinoline Cu(TTA)2(Ql)2, and dimethyl sulfoxide Cu(TTA)2(DMS) in a nitrogen atmosphere were studied under the non-isothermal conditions by simultaneous TG-DTG-DSC technique. The results showed that the evolution of the solvent molecules generally proceeded before the release of TTA in different ways according to their structures. The Cu(TTA)2(Bpy) exhibited a unique decomposition pattern due to its distinctive structure. The dependences of activation energy on extent of reaction for all the stage of each compound were determined by using an isoconversional method, Flynn-Wall-Ozawa equation, which show E values varied with reaction progress, indicating the complexity of these decomposition reactions. In addition, the values of activation energy E for TTA molecules evolution are generally higher than that for the solvent molecules release. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

19.
A supramolecular Cu(II) complex, [Cu(L)2(H2O)]·C2H5OH {HL = 4-[(ethoxyimino)(phenyl)methyl]-5-methyl-2-phenyl-1H-pyrazol-3(2H)-one]} was synthesized and characterized structurally. The structure of the Cu(II) complex consists of one Cu(II) atom, two bidentate L-units, one coordinated H2O and one crystallization ethanol molecule. The Cu(II) atom of the complex has a slightly distorted tetragonal pyramidal geometry. Moreover, every Cu(II) complex molecule links four other molecules into an infinite 2D-layer supramolecular structure via intermolecular O-H…O, O-H…N, and C-H…O hydrogen bonds.  相似文献   

20.
Three multinuclear Cu (II), Zn (II) and Cd (II) complexes, [Cu2(L)(μ‐OAc)]·CHCl2 ( 1 ), [Zn2(L)(μ‐OAc)(H2O)]·3CHCl3 ( 2 ) and [{Cd2(L)(OAc)(CH3CH2OH)}2]·2CH3CH2OH ( 3 ) with a single‐armed salamo‐like dioxime ligand H3L have been synthesized, and characterized by FT‐IR, UV–vis, X‐ray crystallography and Hirshfeld surfaces analyses. The ligand H3L has a linear structure and C‐H···π interactions between the two molecules. The complex 1 is a dinuclear Cu (II) complex, Cu1 and Cu2 are all five‐coordinate possessing distorted square pyramidal geometries. The complex 2 also forms a dinuclear Zn (II) structure, and Zn1 and Zn2 are all five‐coordinate bearing distorted trigonal bipyramidal geometries. The complex 3 is a symmetrical tetranuclear Cd (II) complex, and Cd1 is a hexa‐coordinate having octahedral configuration and Cd2 is hepta‐coordinate with a pentagonal bipyramidal geometry, and it has π···π interactions inside the molecule. In addition, fluorescence properties of the ligand and its complexes 1 – 3 have also been discussed.  相似文献   

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