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1.
P. Ramaiah  A. S. Rao 《合成通讯》2013,43(5-6):931-942
Hydroboration of 4 furnishes a mixture of primary alcohols 5 and 6. The stereochemistry of the crystalline half ester 7 has been established by X-ray studies. While the oxidation of 5 with Jones reagent furnishes the aldehyde 9 in low yield due to the formation of the by product 3, oxidation with Moffatt reagent furnishes the aldehyde 9 in satisfactory yields. cis-Calamenene 1 has been prepared from 9.  相似文献   

2.
Fabrication by co-sintering method of a multilayer pore-free electrode–electrolyte structure promising for use in solid-oxide fuel cell and its characteristics have been studied. A material with high ionic conductivity of La0.88Sr0.12Ga0.82Mg0.18O3–δ (LSGM) served as electrolyte. The composite electrode was formed from a 1: 2 mixture of LSGM and LSFG (La0.7Sr0.3Fe0.95Ga0.05O3–δ). The maximum temperature of the materials co-sintering ability is 1250°C. It was shown by the impedance spectroscopy that the polarization resistance of the LSGM–LSFG electrode is 0.14 Ω cm2 at 800°C.  相似文献   

3.
A series of proposed plasticizers for poly(vinyl chloride) (PVC), based on poly(?-caprolactone) (PCL) with octanoate and benzoate-terminal groups, were synthesized with various microstructures and molecular weights (MW) and tested for biodegradability as well as for mechanical performance, and leaching resistance in blends with PVC. The plasticization efficiency of each was characterized by measuring the glass transition temperature (Tg) and tensile properties of PCL/PVC blends. The PCL-octanoate plasticizers demonstrated plasticization efficiency similar to di(ethylhexyl) phthalate (DEHP) with the same plasticizer loading. PCL-benzoate/PVC blends had much higher Tgs (∼20 °C higher) compared to PCL-octanoate/PVC and DEHP/PVC blends. Yield stresses were about two times higher for PCL-benzoate/PVC blends compared to PCL-octanoate/PVC and DEHP/PVC blends, reflecting the stiffer nature of such blends. Biodegradation was rapid for all PCL-octanoates, with the exception of linear PCL-octanoates with arm molecular weights >103 g mol−1. Biodegradation rates of PCLs by Rhodococcus rhodocrous were not affected by microstructure for the range of PCL topologies studied (linear versus three or four arms) but were slower for PCLs made from commercial PCL-diols that had a central ether linkage due to the initiator used to make these compounds. Leaching resistance was higher as PCL molecular weight increased and, for pairs of comparable sized species, significantly less PCL-benzoate leached out compared to the PCL-octanoate. For the range of PCL topologies studied, the number of arms did not significantly affect leaching resistance. In summary, both the end group and the molecular weight influenced the leaching resistance of the PCL. PCL-octanoates were comparable plasticizers to DEHP in terms of the mechanical properties examined, and were rapidly degraded by a common soil microorganism.  相似文献   

4.
5.
The isothermal and isobaric (vapour + liquid) equilibria for (cis-pinane + α-pinene) and (cis-pinane + 1-butanol) measured with an inclined ebulliometer are presented. The experimental results are analysed using the UNIQUAC equation with the temperature-dependence binary parameters with satisfactory results. Experimental vapour pressures of cis-pinane are also included.  相似文献   

6.
The application of bis-(4-nitrophenyl)phosphorylazide–1,8-diazabicyclo[5.4.0]undec-7-ene system for direct transformation of polyfunctional derivatives of pyrimidin-4(3H)-one in the corresponding 4-azidopyrimidines has been suggested for the first time. Using this system, novel 4-azido-6-(2,6-dihalo-α-methoxybenzyl)-5-methyl-2-(nitroamino)pyrimidines have been obtained in good yield under mild conditions.  相似文献   

7.
Paramagnetic Cu(HL)Cl2 · 0.25CHCl3 (I) and Cu(HL)C12 · 0.25CH2C12 (II), where HL is the optically active morpholino oxime obtained from the terpenoid caryophyllene, were synthesized. The crystals of Cu(HL)Cl2 · CHCl3 (III) were isolated. According to X-ray diffraction data, the crystals of III are composed of acentric mononuclear complex molecules Cu(HL)Cl2 and solvate molecules CHCl3. In the complex molecules, the Cu ion coordinates two N atoms of the bidentate chelating ligand HL and two C1 atoms at the vertices of a distorted tetrahedron. The translationally identical molecules of the complex combined by H-bonds form chains along the axis x.  相似文献   

8.
The first nickel catalyzed deprotonative cross coupling between C(sp3)–H bonds and aryl chlorides is reported, allowing the challenging arylation of benzylimines in the absence of directing group or stoichiometric metal activation. This methodology represents a convenient access to the (diarylmethyl)amine moiety, which is widespread in pharmaceutically relevant compounds.  相似文献   

9.
The structure of tris-complexes of yttrium and lanthanum with malonic dialdehyde (MDA = C3O2H3) is studied by a non-empirical Hartree-Fock method and also with taking into account the electron correlation by the second order Möller-Plesset perturbation theory using the effective pseudo-potentials to describe the atomic cores and two-exponent valence basis sets supplemented with polarization functions. Three most probable geometrical configurations of the D 3, D 3h , and C 2 nuclei symmetry are considered for each molecule. The D 3 structure corresponds to the minimum on the potential energy surface. The D 3h and C 2v configurations correspond to the transition states on the path of two most energetically favorable intramolecular rearrangements. Using the results of our previous calculations for the Sc(MDA)3 molecule, regularities in the change in molecular parameter values of the series Sc(MDA)3→Y(MDA)3→La(MDA)3 are analyzed. The theoretical and experimental structural and spectral data available in the literature are compared.  相似文献   

10.
The hydrolysis of PEtOx is studied to evaluate the potential toxicity of partially hydrolyzed polymers that might interfere with its increasing popularity for biomedical applications. The hydrolysis of PEtOx is studied in the presence of digestive enzymes (gastric and intestinal) and at 5.8 M hydrochloric acid as a function of temperature (57, 73, 90, and 100 °C). It is found that PEtOx undergoes negligible hydrolysis at 37 °C and that thermal and solution properties are not altered when up to 10% of the polymer backbone is hydrolyzed. Mucosal irritation and cytotoxicity is also absent up to 10% hydrolysis levels. In conclusion, PEtOx will not decompose at physiological conditions, and partial hydrolysis will not limit its biomedical applications.

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11.
The influence of the conditions of the struvite synthesis on its ability to form crystals with developed faces of different forms (hkl) and on the possibility of the subsequent transition to more stable forms was examined. The correlation between the ζ-potential of the struvite particle surface, struvite crystal size, and tendency to form agglomerates was demonstrated. The sorption rate in the system consisting of struvite, nickel ions, ammonium ions, and water can be increased by combining the internal diffusion and recrystallization of the solid interaction products. The possibility of enhancing the sorption performance by properly choosing the anionic composition of solutions of nickel salts for the sorption was revealed. The conditions for preparing struvite for its use as agent for improvement of contaminated soils to immobilize heavy metal ions were substantiated.  相似文献   

12.
In this work, a carboxymethyl cellulose (CMC)-modified Fe3O4 (denoted as Fe3O4@CMC) composite was synthesized via a simple co-precipitation approach. Fourier transform infrared spectroscopy, zeta potential and thermogravimetric analysis results indicated that CMC was successfully coated on the Fe3O4 surfaces with a weight percent of ~30 % (w/w). The prepared Fe3O4@CMC composite was stable in acidic solution and could be easily collected with the aid of an external magnet. A batch technique was adopted to check the ability of the Fe3O4@CMC composite to remove Eu(III) as a function of various environmental parameters such as contact time, solution pH, ionic strength, solid content and temperature. The sorption kinetics process achieved equilibrium within a contact time of 7 h. The sorption isotherms were well simulated by the Langmuir model, and the maximum sorption capacity at 293 K was calculated to be 2.78 × 10?4 mol/g, being higher than the series of adsorbent materials reported to date. The ionic strength-independent sorption behaviors, desorption experiments by using ammonium acetate and disodium ethylenediamine tetraacetate as well as the spectroscopic characterization suggested that Eu(III) was sequestrated on the hydroxyl and carboxyl sites of Fe3O4@CMC via inner-sphere complexation. Overall, the Fe3O4@CMC composite could be utilized as a cost-effective adsorbent for the removal of trivalent lanthanide/actinides (e.g., 152+154Eu, 241Am and 244Cm) from radioactive wastewater.  相似文献   

13.
Volatile iridium(I) complexes [Ir(cod)Cpx] (Cpx = pentamethylcyclopentadienyl Cp*, ethylcyclopentadienyl CpEt, cod = 1,5-cyclooctadiene) are synthesized and characterized by IR and NMR spectroscopy. The [Ir(cod)Cp*] complex is a solid and the [Ir(cod)CpEt] complex is a liquid (SATP). The XRD method is used to determine the structure of the [Ir(cod)Cp*] complex: chemical formula C18H27Ir, space group P21/c, a = 8,4418(2) Å, b = 9,4764(3) Å, c = 19.2682(5) Å, β = 96.128(1) °, V = 1532.61(7) Å3, Z = 4, d calc = 1.888 g/cm3, μ = 8.697 mm–1. The cyclopentadienyl ligand is η5-type coordinated; 1,5-cyclooctadiene have a cis-cis conformation and is η4-type coordinated. The thermal properties of the complexes are studied by thermogravimetry.  相似文献   

14.
Ferricyanide ions oxidize Fe(III) up to Fe(VI) in 7–11 M KOH solutions and 10–16 M NaOH solutions. The completeness of the oxidation increases with increasing alkali and ferricyanide concentrations. The presence of KNO2, KAc, and K2C2O4 in 7 M KOH solution increases the Fe(VI) yield. Potassium fluoride in the concentration of 0.02 M does not hinder Fe(VI) formation, but in the concentration of 0.1 M completely suppresses Fe(III) oxidation. The attempt to oxidize Fe(VI) up to Fe(VIII) by the disproportionation of Fe(VI) or by the action of Fe(CN)63− and ozone was unsuccessful due to a high oxidation potential of the Fe(VIII)/(VI) couple.  相似文献   

15.
The new system which consists of the thiol derivative of dipyrromethene–Cu(II) complex created on the surface of a gold electrode was applied for the first time for oriented immobilization of selected His‐tagged domains of a receptor for advanced glycation endproducts (RAGE). Cyclic voltammetry (CV), Osteryoung square‐wave voltammetry (OSWV), electrochemical impedance spectroscopy (EIS) and atomic force microscopy (AFM) were used for characterization of the redox active sensing layer. The biosensor proposed was applied for determination of Aβ16–23′ peptide. In its presence, a decrease of the maximum Cu(II) redox current was observed. These values correlated linearly with the Aβ16–23′ concentration in the range 0.001–1.000 µM. The presence of diluted human plasma has no influence on the sensor responses.  相似文献   

16.
A high yielding method for 1,2-cis-β-D-mannosylation by intra-molecular aglycon delivery (IAD) through p-methoxy benzyl ether/acetal exchange and phenylsulfoxide donor is reported, along with its application in iterative assembly of antigenic (1 → 2)-β-pentamannoside domain of phospholipomannan (PLM) of fungal pathogen Candida albicans.  相似文献   

17.
A new spongy adsorbent (PU-DTC) was prepared with a polyurethane (PU) adsorbent for removal of EDTA-Cu(Ⅱ) and EDTA-Ni(Ⅱ) from water. This new spongy adsorbent was characterized by using SEM and 13C NMR and FT-IR spectroscopy. Adsorption kinetic curve indicated that this new spongy adsorbent could quickly remove EDTA-Cu(Ⅱ) and EDTA-Ni(Ⅱ) from water, and adsorption isotherm also indicated that PU-DTC had high equilibrium adsorption capacity for EDTA-Cu(Ⅱ) and EDTA-Ni(Ⅱ).  相似文献   

18.
Two luminescent Co(II)-based coordination polymers (CPs) with the formulae of [Co(L1)(1,4-ndc)·H2O]n (CP 1) and [Co2(L2)(1,4-chdc)2]n (CP 2) (L1?=?1,1′-(1,4-butanediyl)bis(5,6-dimethylbenzimidazole), 1,4-H2ndc?=?1,4-naphthalenedicarboxylic acid, L2?=?1,1′-(1,4-butanediyl)bis(2-methylbenzimidazole), 1,4-H2chdc?=?1,4-cyclohexanedioic acid) have been synthesized. Both CPs were characterized by single-crystal X-ray diffraction, thermogravimetric analysis, elemental analysis, IR spectroscopy, and powder X-ray diffraction. CP 1 reveals a 2D 3,5L2 framework, while CP 2 has a 2D (4,5)-connected 4,5L51 network. Both CPs are luminescent and can be employed for the selective detection of free MnO4? in water.  相似文献   

19.
Functionalized spiro-tetrahydro-β-carbolines were formed by an efficient gold(I)-catalyzed rearrangement reaction of alkynylaziridine indoles. The reaction involved a Friedel–Crafts type intramolecular reaction of alkynylaziridine indoles, following by hydroamination of aminoallene intermediate.  相似文献   

20.

The industrial production of poly(N‐vinylformamide), PNVF, was started a few years ago, making the desired polyvinylamine, PVAm, accessible on a large scale via hydrolysis of PNVF. According to the literature, the key to achieving a 100% conversion of PNVF into PVAm is to employ basic hydrolysis conditions. However, results disclosed in the present note contradict such statements. A radically obtained PNVF polymer, assigned further on as PNVF‐000 with M¯w=2.63×105 g/mol, was submitted to a stepwise hydrolysis in aq. NaOH solution with periods lasting 0, 5 20, 40, 90, 175, and 240 min. Aliquots ware taken, neutralized, precipitated and purified. For each polymer thus obtained the 13C NMR spectra was recorded, providing evidence for transient formation of amidine rings. These rings while decomposing leave not only primary amine functions attached to the backbone, but also OH groups. Elementary analysis of PNVF‐240, the polymer fully deprived of formaldehyde groups, confirm these findings. From the C/N=3.17 ratio the share of vinyl‐alcohol units present in the chains is estimated to be 42 mol%. Considering all the experimental results, the mechanism of basic hydrolysis was established.  相似文献   

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