scholarly journals Direct oxidation of benzene to phenol catalyzed by a vanadium-substituted heteropolymolybdic acid catalyst

2006 ◽  
Vol 71 (2) ◽  
pp. 111-120 ◽  
Author(s):  
Ying Tang ◽  
Jin Zhang
Keyword(s):  
Hydrogen Peroxide ◽  
Direct Synthesis ◽  
Acid Catalyst ◽  
X Ray Diffraction ◽  
Direct Oxidation ◽  
Experimental Conditions ◽  
X Ray ◽  
Vis Spectroscopy ◽  
Nmr Techniques ◽  
Oxidation Of Benzene

The direct synthesis of phenol by hydroxylation of benzene with hydrogen peroxide over a vanadium substituted heteropolymolybdic acid catalyst was investigated at 70 ?C. Hydrogen peroxide was used as the oxidant while 36 wt.% acetic acid was employed as the solvent. After 100 minutes, the selectivity for phenol was 93% and the yield of phenol was 10.1 %. The catalyst was characterized by elemental analysis, thermogravimetry, infrared spectroscopy, UV-Vis spectroscopy, X-ray diffraction, and 31P-NMR and 51V-NMR techniques. The experimental conditions, such as reaction temperature, the amount of hydrogen peroxide and catalyst, were investigated. The as-prepared phenol could be separated by column chromatography and was characterized by infrared and mass spectrometry.

Baeyer-Villiger Reaction of Adamantanone over Sn-Containing Hydrotalcite-Like Catalysts

2007 ◽  
Vol 119 ◽  
pp. 163-166 ◽  
Author(s):  
Zhi Qiang Yang ◽  
Sang Eon Park
Keyword(s):  
Hydrogen Peroxide ◽  
Ion Exchange ◽  
Direct Synthesis ◽  
Xrd Analysis ◽  
Catalytic Performance ◽  
X Ray Diffraction ◽  
Exchange Method ◽  
X Ray ◽  
Vis Spectroscopy ◽  
Ion Exchange Method

Sn-containing hydrotalcite-like compounds were prepared by three different methods such as (i) direct synthesis, (ii) ion-exchange and (iii) grafting. These catalysts were proved to have framework Sn species by powder X-ray diffraction (XRD) analysis and UV-vis spectroscopy. The catalysts prepared by three methods were found to be active and selective for the liquid phase Baeyer–Villiger (BV) oxidation of admantonone using hydrogen peroxide (H2O2) as an oxidant and acetonitrile as a solvent. The Sn-hydrotalcite-like catalysts prepared by ion-exchange method exhibited better catalytic performance than the catalysts prepared by other two methods. Among the ion-exchanged hydrotalacite-like catalysts, 3% Sn ion-exchanged hydrotalcite exhibited superior activity at 30% conversion and 100% selectivity.

scholarly journals Tailorable Aqueous-Media Synthesis of Heterogeneous Copper Nanoparticles Hybrids and Application in Selective Oxidation of Benzene

2019 ◽  
Author(s):  
Noelia Losada-Garcia ◽  
Alba Rodriguez-Otero ◽  
Jose M Palomo
Keyword(s):  
Hydrogen Peroxide ◽  
Selective Oxidation ◽  
Copper Nanoparticles ◽  
Room Temperature ◽  
Aqueous Media ◽  
Green Technology ◽  
Direct Oxidation ◽  
Experimental Conditions ◽  
Copper Species ◽  
Oxidation Of Benzene

Novel heterogeneous nanocatalysts has been synthesized in aqueous media at multimilligram scale for highly selective direct oxidation of benzene to phenol in aqueous media. The synthesis of a novel biohybrids containing copper nanoparticles (CuNPs) by an efficient and green technology have been described. The methodology involves the combination of an enzyme and a copper salt in aqueous media at room temperature. It was possible to control the copper species and nanoparticle size depending on the experimental conditions, e.g. pH, reducing step, amount of enzyme, obtaining novel heterogeneous nanobiohybrids containing exclusively Cu (0)NPs, Cu2O (Cu(i)) NPs or very crystalline Cu3(PO4)2 (Cu (ii)) NPs. Very small dispersed copper nanoparticles were formed in all cases (from 3 to 15 nm). These novel CuNPs biohybrids were evaluated as catalyst in the selective oxidation of benzene to phenol in water at 30ºC using hydrogen peroxide as oxidant, obtaining excellent yields and selectivity of phenol (>80% yield, >95% selectivity). <br>

scholarly journals Tailorable Aqueous-Media Synthesis of Heterogeneous Copper Nanoparticles Hybrids and Application in Selective Oxidation of Benzene

2019 ◽  
Author(s):  
Noelia Losada-Garcia ◽  
Alba Rodriguez-Otero ◽  
Jose M Palomo
Keyword(s):  
Hydrogen Peroxide ◽  
Selective Oxidation ◽  
Copper Nanoparticles ◽  
Room Temperature ◽  
Aqueous Media ◽  
Green Technology ◽  
Direct Oxidation ◽  
Experimental Conditions ◽  
Copper Species ◽  
Oxidation Of Benzene

Novel heterogeneous nanocatalysts has been synthesized in aqueous media at multimilligram scale for highly selective direct oxidation of benzene to phenol in aqueous media. The synthesis of a novel biohybrids containing copper nanoparticles (CuNPs) by an efficient and green technology have been described. The methodology involves the combination of an enzyme and a copper salt in aqueous media at room temperature. It was possible to control the copper species and nanoparticle size depending on the experimental conditions, e.g. pH, reducing step, amount of enzyme, obtaining novel heterogeneous nanobiohybrids containing exclusively Cu (0)NPs, Cu2O (Cu(i)) NPs or very crystalline Cu3(PO4)2 (Cu (ii)) NPs. Very small dispersed copper nanoparticles were formed in all cases (from 3 to 15 nm). These novel CuNPs biohybrids were evaluated as catalyst in the selective oxidation of benzene to phenol in water at 30ºC using hydrogen peroxide as oxidant, obtaining excellent yields and selectivity of phenol (>80% yield, >95% selectivity). <br>

scholarly journals Direct Synthesis of Porous Multilayer Graphene Materials Using Thermal Plasma at Low Pressure

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Ravil Amirov ◽  
Marina Shavelkina ◽  
Nariman Alihanov ◽  
Evgeny Shkolnikov ◽  
Alexander Tyuftyaev ◽  
...  
Keyword(s):  
Thermal Plasma ◽  
Direct Synthesis ◽  
Plasma Jet ◽  
Multilayer Graphene ◽  
X Ray Diffraction ◽  
Experimental Conditions ◽  
X Ray ◽  
Wide Range ◽  
Morphology And Structure ◽  
Decomposition Of Hydrocarbons

Porous multilayer graphenes have been synthesized by decomposition of hydrocarbons in a thermal plasma jet. Products of synthesis were characterized by electron microscopy, thermogravimetry, Raman spectroscopy, and X-ray diffraction. Possibility of producing a wide range of graphene materials with different morphology and structure has been shown. Influence of the experimental conditions on mesopores structure of the synthesis products has been investigated using the method of “limited evaporation.”

scholarly journals Zeolite NaP1 Functionalization for the Sorption of Metal Complexes with Biodegradable N-(1,2-dicarboxyethyl)-D,L-aspartic Acid

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2518
Author(s):  
Dorota Kołodyńska ◽  
Yongming Ju ◽  
Małgorzata Franus ◽  
Wojciech Franus
Keyword(s):  
Experimental Data ◽  
Aspartic Acid ◽  
Ph Value ◽  
Complexing Agents ◽  
X Ray Diffraction ◽  
Experimental Conditions ◽  
Modified Zeolite ◽  
X Ray ◽  
Slow Release Fertilizers ◽  
Pseudo Second Order

The possibility of application of chitosan-modified zeolite as sorbent for Cu(II), Zn(II), Mn(II), and Fe(III) ions and their mixtures in the presence of N-(1,2-dicarboxyethyl)-D,L-aspartic acid, IDHA) under different experimental conditions were investigated. Chitosan-modified zeolite belongs to the group of biodegradable complexing agents used in fertilizer production. NaP1CS as a carrier forms a barrier to the spontaneous release of the fertilizer into soil. The obtained materials were characterized by Fourier transform infrared spectroscopy (FTIR); surface area determination (ASAP); scanning electron microscopy (SEM-EDS); X-ray fluorescence (XRF); X-ray diffraction (XRD); and carbon, hydrogen, and nitrogen (CHN), as well as thermogravimetric (TGA) methods. The concentrations of Cu(II), Zn(II), Mn(II), and Fe(III) complexes with IDHA varied from 5–20 mg/dm3 for Cu(II), 10–40 mg/dm3 for Fe(III), 20–80 mg/dm3 for Mn(II), and 10–40 mg/dm3 for Zn(II), respectively; pH value (3–6), time (1–120 min), and temperature (293–333 K) on the sorption efficiency were tested. The Langmuir, Freundlich, Dubinin–Radushkevich, and Temkin adsorption models were applied to describe experimental data. The pH 5 proved to be appropriate for adsorption. The pseudo-second order and Langmuir models were consistent with the experimental data. The thermodynamic parameters indicate that adsorption is spontaneous and endothermic. The highest desorption percentage was achieved using the HCl solution, therefore, proving that method can be used to design slow-release fertilizers.

Nanocrystalline Solutions as Precursors to The Spray Deposition of Cdte Thin Films

1995 ◽  
Vol 382 ◽  
Author(s):  
Martin Pehnt ◽  
Douglas L. Schulz ◽  
Calvin J. Curtis ◽  
Helio R. Moutinho ◽  
Amy Swartzlander ◽  
...  
Keyword(s):  
Thin Films ◽  
Atomic Force Microscopy ◽  
Grain Size ◽  
X Ray Diffraction ◽  
X Ray ◽  
Force Microscopy ◽  
Cdte Nanoparticles ◽  
Atomic Force ◽  
Vis Spectroscopy ◽  
Cdte Thin Films

ABSTRACTIn this article we report the first nanoparticle-derived route to smooth, dense, phase-pure CdTe thin films. Capped CdTe nanoparticles were prepared by injection of a mixture of Cd(CH3)2, (n-C8H17)3 PTe and (n-C8H17)3P into (n-C8H17)3PO at elevated temperatures. The resultant nanoparticles 32-45 Å in diameter were characterized by x-ray diffraction, UV-Vis spectroscopy, transmission electron microscopy, thermogravimetric analysis and energy dispersive x-ray spectroscopy. CdTe thin film deposition was accomplished by dissolving CdTe nanoparticles in butanol and then spraying the solution onto SnO2-coated glass substrates at variable susceptor temperatures. Smooth and dense CdTe thin films were obtained using growth temperatures approximately 200 °C less than conventional spray pyrolysis approaches. CdTe films were characterized by x-ray diffraction, UV-Vis spectroscopy, atomic force microscopy, and Auger electron spectroscopy. An increase in crystallinity and average grain size as determined by x-ray diffraction was noted as growth temperature was increased from 240 to 300 °C. This temperature dependence of film grain size was further confirmed by atomic force microscopy with no remnant nanocrystalline morphological features detected. UV-Vis characterization of the CdTe thin films revealed a gradual decrease of the band gap (i.e., elimination of nanocrystalline CdTe phase) as the growth temperature was increased with bulk CdTe optical properties observed for films grown at 300 °C.

Salts of purine alkaloids caffeine and theobromine with 2,6-dihydroxybenzoic acid as coformer: structural, theoretical, thermal and spectroscopic studies

2021 ◽  
Vol 77 (11) ◽  
Author(s):  
Mateusz Gołdyn ◽  
Anna Komasa ◽  
Mateusz Pawlaczyk ◽  
Aneta Lewandowska ◽  
Elżbieta Bartoszak-Adamska
Keyword(s):  
Hydrogen Bonds ◽  
Water Solubility ◽  
Theoretical Calculations ◽  
Spectroscopic Studies ◽  
X Ray Diffraction ◽  
Dihydroxybenzoic Acid ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Purine Alkaloids ◽  
Vis Spectroscopy

The study of various forms of pharmaceutical substances with specific physicochemical properties suitable for putting them on the market is one of the elements of research in the pharmaceutical industry. A large proportion of active pharmaceutical ingredients (APIs) occur in the salt form. The use of an acidic coformer with a given structure and a suitable pK a value towards purine alkaloids containing a basic imidazole N atom can lead to salt formation. In this work, 2,6-dihydroxybenzoic acid (26DHBA) was used for cocrystallization of theobromine (TBR) and caffeine (CAF). Two novel salts, namely, theobrominium 2,6-dihydroxybenzoate, C7H9N4O2 +·C7H5O4 − (I), and caffeinium 2,6-dihydroxybenzoate, C8H11N4O2 +·C7H5O4 − (II), were synthesized. Both salts were obtained independently by slow evaporation from solution, by neat grinding and also by microwave-assisted slurry cocrystallization. Powder X-ray diffraction measurements proved the formation of the new substances. Single-crystal X-ray diffraction studies confirmed proton transfer between the given alkaloid and 26DHBA, and the formation of N—H...O hydrogen bonds in both I and II. Unlike the caffeine cations in II, the theobromine cations in I are paired by noncovalent N—H...O=C interactions and a cyclic array is observed. As expected, the two hydroxy groups in the 26DHBA anion in both salts are involved in two intramolecular O—H...O hydrogen bonds. C—H...O and π–π interactions further stabilize the crystal structures of both compounds. Steady-state UV–Vis spectroscopy showed changes in the water solubility of xanthines after ionizable complex formation. The obtained salts I and II were also characterized by theoretical calculations, Fourier-transform IR spectroscopy (FT–IR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and elemental analysis.

A Two-step Electrodeposition of Pd-Cu/Cu2O Nanocomposite on FTO Substrate for Non-enzymatic Hydrogen Peroxide Sensor

2021 ◽  
Vol 17 ◽  
Author(s):  
Ke Huan ◽  
Li Tang ◽  
Dongmei Deng ◽  
Huan Wang ◽  
Xiaojing Si ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Cyclic Voltammetry ◽  
Photoelectron Spectroscopy ◽  
Chemical Structure ◽  
Pd Nanoparticles ◽  
Optimal Conditions ◽  
Potential Oscillation ◽  
X Ray Diffraction ◽  
X Ray

Background: Hydrogen peroxide (H2O2) is a common reagent in the production and living, but excessive H2O2 may enhance the danger to the human body. Consequently, it is very important to develop economical, fast and accurate techniques for detecting H2O2. Methods: A simple two-step electrodeposition process was applied to synthesize Pd-Cu/Cu2O nanocomposite for non-enzymatic H2O2 sensor. Cu/Cu2O nanomaterial was firstly electrodeposited on FTO by potential oscillation technique, and then Pd nanoparticles were electrodeposited on Cu/Cu2O nanomaterial by cyclic voltammetry. The chemical structure, component, and morphology of the synthesized Pd-Cu/Cu2O nanocomposite were characterized by X-ray diffraction, scanning electron microscopy and X-ray photoelectron spectroscopy. The electrochemical properties of Pd-Cu/Cu2O nanocomposite were studied by cyclic voltammetry and amperometry. Results: Under optimal conditions, the as-fabricated sensor displayed a broad linear range (5-4000 µM) and low detection limit (1.8 µM) for the determination of H2O2. The proposed sensor showed good selectivity and reproducibility. Meanwhile, the proposed sensor has been successfully applied to detect H2O2 in milk. Conclusion: The Pd-Cu/Cu2O/FTO biosensor exhibits excellent electrochemical activity for H2O2 reduction, which has great potential application in the field of food safety.

scholarly journals Thermal and optical properties of new poly(amide-imide)-nanocomposite reinforced by layer silicate based on chiral n-trimellitylimido-L-valine

2012 ◽  
Vol 31 (1) ◽  
pp. 79
Author(s):  
Khalil Faghihi ◽  
Masoumeh Soleimani ◽  
Shabnam Nezami ◽  
Meisam Shabanian
Keyword(s):  
Main Chain ◽  
Nanocomposite Films ◽  
Direct Polycondensation ◽  
Polycondensation Reaction ◽  
X Ray Diffraction ◽  
Solution Intercalation ◽  
X Ray ◽  
Vis Spectroscopy ◽  
Polymeric Chains ◽  
Morphology And Structure

Two new samples of poly(amide-imide)-montmorillonite reinforced nanocomposites containing N-trimellitylimido-L-valine moiety in the main chain were synthesized by a convenient solution intercalation technique. Poly(amide-imide) (PAI) 5 as a source of polymer matrix was synthesized by the direct polycondensation reaction of N-trimellitylimido-L-valine (3) with 4,4′-diaminodiphenyl ether 4 in the presence of triphenyl phosphite (TPP), CaCl2, pyridine and N-methyl-2-pyrrolidone (NMP). Morphology and structure of the resulting PA-nanocomposite films (5a) and (5b) with 10 and 20 % silicate particles were characterized by FTIR spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM). The effect of clay dispersion and the interaction between clay and polymeric chains on the properties of nanocomposite films were investigated by using Uv-vis spectroscopy,  thermogravimetric analysis (TGA) and water uptake measurements.

scholarly journals A Covalent Organic Cage Compound Acting as a Supramolecular Shadow Mask for the Regioselective Functionalization of C60

2020 ◽  
Author(s):  
Viktoria Leonhardt ◽  
Stefanie Fimmel ◽  
Ana-Maria Krause ◽  
Florian Beuerle
Keyword(s):  
Mass Spectrometry ◽  
Single Crystal ◽  
High Selectivity ◽  
Shadow Mask ◽  
X Ray Diffraction ◽  
X Ray ◽  
Trigonal Bipyramidal ◽  
Cage Compound ◽  
Vis Spectroscopy ◽  
Regioselective Functionalization

<div><div><div><p>A trigonal-bipyramidal covalent organic cage compound serves as an efficient host to form stable 1:1-complexes with C60 and C70. Fullerene encapsulation has been comprehensively studied by NMR and UV/Vis spectroscopy, mass spectrometry as well as single-crystal X-ray diffraction. Exohedral functionalization of encapsulated C60 via threefold Prato reaction revealed high selectivity for the symmetry-matched all-trans-3 addition pattern.</p></div></div></div>

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