Catalyst In High Yields Research Articles

Ni Particle Morphology and Support Effect in the Catalytic Decomposition of Methane: Into the Design of Novel, High Yield Catalyst for Catalytic Decomposition of Methane

Ni Particle Morphology and Support Effect in the Catalytic Decomposition of Methane: Into the Design of Novel, High Yield Catalyst for Catalytic Decomposition of Methane

Protonated Chiral 1,2-Diamine Organocatalysts for N-Selective Nitroso Aldol Reaction

The introduction of nitrogen to carbonyl groups is considered both challenging and highly desirable by those who work in the field of organic synthesis. In this study, a diphenylethylenediamine-derived catalyst demonstrating N-selectivity was designed using a quantum calculation for the nitroso aldol reaction. The reductive monoalkylation of (R,R)-(+)-1,2-diphenylethylenediamine afforded an organic chiral diamine catalyst in high yield. The expected reaction mechanism for the nitroso aldol reaction was determined, and the product and solvent conditions were optimized through quantum calculations. The calculation results revealed that the enantioselectivity is determined by the hydrogen bond between the alkyl substituent of the chiral diamine and the oxygen of the aromatic aldehyde on the ammonium moiety. The reaction was found to proceed optimally in the presence of 5 mol % catalyst at −10 °C in brine. Using these conditions, an eco-friendly nitroso aldol reaction was performed in which the organic catalyst and cyclohexanone formed enamine. Nitrosobenzene, activated by hydrogen bonding with an ammonium catalyst, was used to minimize the steric hindrance between the catalyst and the reactant, resulting in high enantioselectivity. A nitroso aldol product with high N-selectivity and enantioselectivity (98% ee) was obtained in 95% yield. The catalyst developed in this study provides a less expensive and more environmentally friendly alternative for the nitroso aldol reaction.

Oxidative esterification of alcohols by a single-side organically decorated Anderson-type chrome-based catalyst

An efficient strategy was reported for oxidative esterification reaction by a single-side organic decorated Anderson-type chrome-based catalyst in high yield. The CrIIIMo6-OH could be simply recycled many times and maintain high catalytic activity.

A polyelectrolytic polyacetylene for quasi-solid state dye-sensitized solar cell applications

A new polyelectrolytic polyacetylene, poly(2-ethynyl-N-iodopyridinium triiodide), was applied for DSSCs. Poly(2-ethynyl-N-iodopyridinium triiodide) was prepared by the non-catalyst polymerization of 2-ethynylpyridine using iodine without any additional initiator or catalyst in high yields. The photoluminescence peak was observed at 534 nm corresponding to a photon energy of 2.32 eV. Quasi-solid-state DSSCs with a SnO2:F/TiO2/D719 dye/solid-state electrolyte/Pt device was fabricated with the poly(2-ethynyl-N-iodopyridinium triiodide) electrolyte, which shows the power conversion efficiency (PCE) of 5.79%.

Ultrasound Assisted Synthesis of 1,5-Disubstituted Pyrazole using Cu(I) Catalyst

A new efficient and convenient approach towards the synthesis of pyrazole is described. The α,β-unsaturated cyanoesters were obtained from substituted benzaldehyde and ethyl cyanoacetate by reported methods. 1,5-Disubstituted pyrazoles were synthesized from α,β-unsaturated cyanoester and phenyl hydrazine using sodium ethoxide as a base in the presence of 10 mol % Cu(I) catalyst in high yields within 75-90 min under ultrasound irradiation at 60 ºC. The reaction rate is enhanced tremendously under ultrasound irradiation as compare to conventional methods with improved yields are recorded.

Ultrasound Assisted Cu(I) Catalyzed Aza-Michael Reactions in Water

The β-amino compounds were synthesized from α,β-unsaturated esters, nitriles and amine using water as a solvent in the presence of 10 mol % Cu(I) catalyst in high yields within 2-5 min under ultrasound irradiation at room temperature. The reaction rate was enhanced tremendously under ultrasound irradiation as compared to conventional methods with improved yields have been recorded.

In situ biogenic synthesis of functionalized magnetic nanoparticles with Ni complex by using a plant extract (Pistachio Leaf) and its catalytic evaluation towards polyhydroquinoline derivatives in green conditions

The purpose of this work is to prepare a magnetically green nanocatalyst by using Pistachio Leaf extract and its catalytic evaluation towards polyhydroquinoline. This nanostructure characterized by XRD, FT-IR, VSM, EDX mapping and SEM. It has been observed that the polyhydroquinoline derivatives were successful synthesized in the presence of new catalyst in short time and high yield.

Cu nanoparticles immobilized on modified magnetic zeolite for the synthesis of 1,2,3‐triazoles under ultrasonic conditions

Magnetically recoverable copper nanoparticle‐loaded natural zeolite (CuNPs/MZN) as an efficient catalyst was synthesized. The Fe3O4 magnetic nanoparticles were immobilized into the pores of natural clinoptilolite zeolite, which were modified with epichlorohydrine and ethylenediamine species and then CuNPs were decorated on the surface of functionalized zeolite (CuNPs/MZN). The catalysts were successfully characterized by Fourier transform‐infrared, CHN, thermogravimetric analysis, inductively coupled plasma, X‐ray diffraction, scanning electron microscopy and transmission electron microscopy techniques. The 1,2,3‐triazoles were readily synthesized through using the catalyst in high yields and short reaction times under ultrasonic conditions via CuAAC reactions of aryl azides and terminal alkynes. The CuNPs/MZN was easily separated from the reaction mixture by an external magnet and reused several times successfully. The catalyst could be used for the synthesis of various organic compounds.

The influence of intimacy on the ‘iterative reactions’ during OX-ZEO process for aromatic production

Abstract The oxide-zeolite process provides a promising way for one-step production of aromatics from syngas, whereas the reasons for the dramatic effect of intimacy between oxide and zeolite in the composite catalyst on the product selectivity are still unclear. In order to explore the optimal intimacy and the essential influence factors, ZnCrOx combined with ZSM-5 are employed to prepare the composite catalysts with different distances between the two components by changing the mixing methods. An aromatic selectivity of 74% (with CO conversion to be 16%) is achieved by the composite catalyst when the intimacy is in the range of nanometer. A so-called ‘iterative reactions’ mechanism of intermediates over oxides is then proposed and studied: the intermediate chemical can undergo a hydrogenation reaction on oxide. So the shorter the intermediates stay on oxide, the more of chance for C − C coupling takes place on zeolite to form aromatics. Moreover, the aero-environments of reaction is found to impact on the extent of iterative reaction as well. Therefore, when the intimacy between the two components changes, the extent of iterative reactions vary, resulting in alteration of product distribution. This work provides new insight in understanding the mechanisms during the complex process of OX-ZEO composite catalysis and sheds light to the design of a high-yield catalyst for synthetization of aromatics from syngas.

Eco‐friendly magnetic clinoptilolite containing Cu(0) nanoparticles (CuNPs/MZN): as a new efficient catalyst for the synthesis of propargylamines via A3 and KA2 coupling reactions

In this reaserch a new and eco‐friendly magnetic catalyst for the synthesis of propargylamines is reported. Initial incorporation of Fe3O4 magnetic nanoparticles (MNPs) into the pores of the natural clinoptilolite zeolite followed by modification with epichlorohydrine and ethylenediamine and then immobilization of CuNPs on the surface of functionalized zeolite gave the desired catalyst (CuNPs/MZN). The CuNPs/MZN was fully characterized by various techniques such as FT‐IR, CHN, TGA, ICP, XRD, SEM, TEM and BET. A host of propargylamines were readily synthesized through using the catalyst in high yields and short reaction times via A3 and KA2 coupling reactions of aldehydes/ketones, amines, and phenylacetylene. The CuNPs/MZN was easily separated from the reaction mixture by an external magnet and reused several times successfully. The catalyst has the potential for catalysis of various organic transformations.

Mild incorporation of CO2 into epoxides: Application to nonisocyanate synthesis of poly(hydroxyurethane) containing triazole segment by polyaddition of novel bifunctional five‐membered cyclic carbonate and diamines

ABSTRACTThe cyclic amidinium iodide effectively catalyzed the ring‐expansion addition of epoxides with carbon dioxide under ordinary pressure and mild conditions to obtain the corresponding five‐membered cyclic carbonates in high yield. The novel triazole‐linked bifunctional five‐membered cyclic carbonate was synthesized successfully by the click reaction of the azide‐ and the alkyne‐substituted five‐membered cyclic carbonates under ambient temperature in high yield. The chemical structure of the novel bis(cyclic carbonate) was characterized by one‐ and two‐dimensional nuclear magnetic resonance spectra. The obtained bis(cyclic carbonate) was converted with commercially available diamines to poly(hydroxyurethane) containing triazole segment without catalyst in high yield. Analyses of the resulting poly(hydroxyurethane)s were performed by proton nuclear magnetic resonance, size exclusion chromatography, thermogravimetric analysis, and differential scanning calorimetry. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 986–993

Cu(II)-Schiff base/SBA-15 as an efficient catalyst for synthesis of decahydroacridine-1,8-diones

Herein, we report a fast synthesis of 1,4-dihydropyridines, decahydroacridine-1,8-diones by one-pot multi-component reaction of 1,3-cyclohexanedione or dimidone, arylaldehydes, and ammonium acetate under solvent-less condition using Cu(II)-schiff base-SBA-15 as a reusable heterogeneous catalyst in high yields. These kinds of catalysts are built from mesoporous silica SBA-15 which was covalently anchored with Cu(II) schiff base complex. The shorter reaction times, good yields, simple work-up procedure and environmentally friendly conditions are the main advantages of this method compared to the last one. This method is also the first example of synthesizing acridines by Cu(II)-schiff base-SBA-15 as an efficient catalyst in solvent-free media which can be valuable to be used or investigated for similar systems. The product was identified by its 1H NMR, mass and IR spectra, which were compared to those reported previously.

Catalytic Asymmetric Electrophilic Cyanation of 3-Substituted Oxindoles.

The first example of catalytic asymmetric electrophilic cyanation of 3-substituted oxindoles has been achieved using readily accessible 4-acetylphenyl cyanate as the cyano source. Thus, a series of all-carbon quaternary center 3-aryl-3-cyano oxindoles were prepared using a zinc complex of a chiral pincer ligand as the catalyst in high yields (up to 95%) and excellent enantioselectivities (up to >99% ee) in the presence of 4 Å MS and 2,6-lutidine in THF at 0 °C.

Solvent-Directed Epoxide Opening with Primary Amines for the Synthesis of β-Amino Alcohols

An efficient synthesis of β-amino alcohols from a variety of epoxides and primary unbranched amines in the absence of any catalyst in high yields and regioselectivities is reported. A variety of polar mixed solvent systems allow for the selective formation of secondary amino alcohols over tertiary amino alcohols. The reaction scope extends to a wide variety of aromatic and aliphatic substituted epoxides and primary amines bearing complex functionality.

ChemInform Abstract: Efficient and Environmentally Friendly Glaser Coupling of Terminal Alkynes Catalyzed by Multinuclear Copper Complexes under Base‐Free Conditions.

Abstract1,3‐Diynes are prepared by the title coupling using a dinuclear copper complex (COP) as catalyst in high yields.

Rapid synthesis of novel 1,8-dioxoacridine carboxylic acid derivatives by microwave irradiation and their free radical scavenging activity

Synthesis of novel acridine carboxylic acid compounds 4–18 was performed with the reaction of 4-aminobenzoic acid 1, aromatic aldehyde 2a–n, 1,3-diketone 3a, 3b using microwave irradiation. These compounds were synthesized efficiently in one-pot procedure for 6 min without catalyst in high yields of 65–90 % using little ethanol. Radical scavenging activities of synthesized compounds 4–18 were determined by means of in vitro test using 2,2-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid radicals (ABTS·+). The activities of tested compounds were compared to the positive control such as butylated hydroxyanisole, butylated hydroxytoluene, and trolox. The results showed that the synthesized compounds 4, 6, 14, and 15 had effective free radical scavenging activity.

Synergistic H4NI-AcOH Catalyzed Oxidation of the Csp(3)-H Bonds of Benzylpyridines with Molecular Oxygen.

The oxidation of benzylpyridines forming benzoylpyridines was achieved based on a synergistic H4NI-AcOH catalyst and molecular oxygen in high yield under solvent-free conditions. This is the first nonmetallic catalytic system for this oxidation transformation using molecular oxygen as the oxidant. The catalytic system has a wide scope of substrates and excellent chemoselectivity, and this procedure can also be scaled up. The study of a preliminary reaction mechanism demonstrated that the oxidation of the Csp(3)-H bonds of benzylpyridines was promoted by the pyridinium salts formed by AcOH and benzylpyridines. The synergistic effect of H4NI-AcOH was also demonstrated by control experiments.

Cerium ammonium nitrate-catalyzed aerobic oxidative coupling of dithiocarbamates: facile synthesis of thioureas and bis(aminothiocarbonyl)disulfides

Diverse disubstituted and trisubstituted thioureas were synthesized by the condensation of dithiocarbamate TEA (or DABCO) salts and amines using cerium ammonium nitrate (CAN) as a catalyst in high yields at room temperature. It is a one-pot method and it is unnecessary to isolate isothiocyanates. This reaction probably took place through nucleophilic addition of amines to isothiocyanates, which were generated by oxidative coupling of dithiocarbamates and the following decomposition of bis(aminothiocarbonyl)disulfides. When secondary amines and CS2 served as the reactants, bis(aminothiocarbonyl)disulfides were obtained via tandem nucleophilic addition/oxidative coupling reactions in moderate to excellent yields. In all the coupling reactions, the oxidant was air and CAN possibly acted as an SET catalyst.

Synthesis of 2-arylbenzothiazoles using nano BF3/SiO2 as a reusable and efficient heterogeneous catalyst under mild conditions

2-Arylbenzothiazoles were synthesized via condensation of 2-aminothiophenol and different aldehydes catalyzed by nano silica-supported boron trifluoride (nano BF3/SiO2) as an efficient and reusable catalyst in high yields and short reaction times. The reactions proceeded at room temperature under mild conditions to afford 2-arylbenzothiazole derivatives. The pure products were identified and characterized by physical and spectroscopic data such as IR, 1H NMR, 13C NMR and Mass spectroscopy.

Catalyst free, base free microwave irradiated synthesis of aryl nitrites from potassium aryltrifluoroborates and bismuth nitrate

A mixture of bismuth nitrate pentahydrate and potassium aryltrifluoroborate in toluene under microwave heating at 120°C for 20min provides an interesting and mild reaction protocol for the synthesis of aryl nitrite. The conversion to aryl nitrites from aryltrifluoroborates without transition metal catalyst and base in high yields is remarkable.