scholarly journals Diazotization-azo coupling reaction of alphnaphthol over silica-sulfaric acid catalyst

2022 ◽  
Vol 961 (1) ◽  
pp. 012020
Author(s):  
Haneen Majed Saheb ◽  
Elham Kadhim Hilal ◽  
Kasim Mohammed Hello
Keyword(s):  
Azo Dyes ◽  
Diazonium Salt ◽  
Coupling Reaction ◽  
Acid Catalyst ◽  
Coupling Reactions ◽  
Sulfate Content ◽  
Laboratory Procedure ◽  
Tem Analysis ◽  
Pure Silica

Abstract Using agrowaste as a source of recycled materials is a hot topic among experts and technologists these days. Waste materials can be converted into energy and new products by using them. As a rice waste, rice husk (RH) is a rich source of pure silica that is recyclable. The pure silica in RH was sulfonated by agitating and reacting it with diluted sulfuric acid. Various sulfate concentrations were loaded on silica (5, 10, 15, and 20%), andthe catalyst was designated as RHASO4. As the sulfate content increased, the specific surface area decreased. TEM analysis showed different forms of catalyst, including spherical, cylindrical, and fibbered forms. The catalyst was used for the in-situ generation of nitrose acid to prepare a diazonium salt for aromatic coupling reactions. Our experiment indicates that azo dyes can be produced at 68 percent over the catalyst at 10 degrees Celsius, while traditional catalysts cannot produce them above 5 degrees Celsius. For the highest yield of azo dyes, a 20% sulfate loading is optimum. A simple laboratory procedure is followed to reuse a catalyst without deteriorating its properties.

scholarly journals Efficient in situ N-heterocyclic carbene palladium(ii) generated from Pd(OAc)2 catalysts for carbonylative Suzuki coupling reactions of arylboronic acids with 2-bromopyridine under inert conditions leading to unsymmetrical arylpyridine ketones: synthesis, characterization and cytotoxic activities

RSC Advances ◽  
2018 ◽  
Vol 8 (70) ◽  
pp. 40000-40015 ◽  
Author(s):  
Nedra Touj ◽  
Abdullah S. Al-Ayed ◽  
Mathieu Sauthier ◽  
Lamjed Mansour ◽  
Abdel Halim Harrath ◽  
...  
Keyword(s):  
Coupling Reaction ◽  
Cross Coupling ◽  
Suzuki Coupling ◽  
Boronic Acids ◽  
Cytotoxic Activities ◽  
Coupling Reactions ◽  
Component System ◽  
Arylboronic Acids ◽  
Cross Coupling Reaction

The in situ prepared four component system Pd(OAc)2, 1,3-dialkylbenzimidazolium halides 2a–i and 4a–i, K2CO3 under CO atmosphere catalyses carbonylative cross-coupling reaction of 2-bromopyridine with various boronic acids to yield unsymmetrical arylpyridine ketones.

An easily prepared palladium-hydrogel nanocomposite catalyst for C–C coupling reactions

2014 ◽  
Vol 2 (44) ◽  
pp. 18952-18958 ◽  
Author(s):  
Mitasree Maity ◽  
Uday Maitra
Keyword(s):  
Palladium Nanoparticles ◽  
Room Temperature ◽  
Coupling Reaction ◽  
Coupling Reactions ◽  
Sodium Cyanoborohydride ◽  
Efficient Catalyst ◽  
Suzuki Coupling Reaction ◽  
Reaction In Water ◽  
Hydrogel Nanocomposite

Palladium nanoparticles were efficiently prepared in situ by sodium cyanoborohydride reduction of Pd(ii) at room temperature using calcium-cholate hydrogel fibers as templates. The PdNPs self-organize on the gel fibers, which supports the controlled growth as well as stabilization of PdNPs. The hybrid xerogel was used as an efficient catalyst for the Suzuki coupling reaction in water.

scholarly journals Thiol–ene coupling reaction achievement and monitoring by “in situ” UV irradiation NMR spectroscopy

RSC Advances ◽  
2020 ◽  
Vol 10 (42) ◽  
pp. 25214-25222
Author(s):  
Natalia Toncheva-Moncheva ◽  
Miroslav Dangalov ◽  
Nikolay G. Vassilev ◽  
Christo P. Novakov
Keyword(s):  
Nmr Spectroscopy ◽  
Uv Irradiation ◽  
Glycidyl Ether ◽  
Coupling Reaction ◽  
Polyethylene Glycols ◽  
Coupling Reactions ◽  
Uv Illumination ◽  
Allyl Glycidyl Ether

An “In situ” LED UV illumination NMR setup for achievement of initiator-free coupling reactions of allyl-functionalized poly(allyl glycidyl ether) with polyethylene glycols thiols.

scholarly journals Enantioselective Iron/Bisquinolyldiamine Ligand-Catalyzed Oxidative Coupling Reaction of 2-Naphthols

Molecules ◽  
2020 ◽  
Vol 25 (4) ◽  
pp. 852 ◽  
Author(s):  
Lin-Yang Wu ◽  
Muhammad Usman ◽  
Wen-Bo Liu
Keyword(s):  
Oxidative Coupling ◽  
Coupling Reaction ◽  
Iron Complex ◽  
Coupling Reactions ◽  
Oxidative Coupling Reaction ◽  
Oxidative Coupling Reactions

An iron-catalyzed asymmetric oxidative homo-coupling of 2-naphthols for the synthesis of 1,1′-Bi-2-naphthol (BINOL) derivatives is reported. The coupling reaction provides enantioenriched BINOLs in good yields (up to 99%) and moderate enantioselectivities (up to 81:19 er) using an iron-complex generated in situ from Fe(ClO4)2 and a bisquinolyldiamine ligand [(1R,2R)-N1,N2-di(quinolin-8-yl)cyclohexane-1,2-diamine, L1]. A number of ligands (L2–L8) and the analogs of L1, with various substituents and chiral backbones, were synthesized and examined in the oxidative coupling reactions.

scholarly journals Palladium-catalyzed Suzuki-Miyaura coupling of thioureas or thioamides

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Shaoyu Mai ◽  
Wendong Li ◽  
Xue Li ◽  
Yingwei Zhao ◽  
Qiuling Song
Keyword(s):  
Silver Salt ◽  
Coupling Reaction ◽  
Coupling Reactions ◽  
Mechanistic Studies ◽  
Aromatic Rings ◽  
Cross Coupling Reactions ◽  
Broad Array ◽  
Palladium Catalyzed

AbstractCross-coupling reactions involving metal carbene intermediates play an increasingly important role in C–C bond formation. Expanding the carbene precursors to a broader range of starting materials and more diverse products is an ongoing challenge in synthetic organic chemistry. Herein, we report a Suzuki-Miyaura coupling reaction of in situ-generated Pd–carbene complexes via desulfurization of thioureas or thioamides. This strategy enables the preparation of a broad array of substituted amidinium salts and unsymmetrical diaryl ketones. The reaction is readily scalable, compatible with bromo groups on aromatic rings, tolerant to moisture and air and has a broad substrate scope. Furthermore, a single crystal structure of Pd-diaminocarbene complex is obtained and proven to be the key intermediate in both catalytic and stoichiometric reactions. Preliminary mechanistic studies demonstrate the dual role of the silver salt as a desulfurating reagent assisting the elimination of sulfur and as oxidant facilitating the PdII/Pd0/PdII catalytic cycle.

In Situ Coloration of Silk with Coupling Reaction and the Spectrum Characteristics

2013 ◽  
Vol 796 ◽  
pp. 428-431
Author(s):  
Wei Guo Chen ◽  
Zong Qian Wang ◽  
Zhi Hua Cui ◽  
Zhao Cheng Meng
Keyword(s):  
Silk Fibroin ◽  
Coupling Reaction ◽  
Coupling Reactions ◽  
Tyrosine Residue ◽  
Fastness Properties ◽  
Silk Industry ◽  
Tyrosine Residues ◽  
Spectrum Characteristics ◽  
Dyeing Method

High wet fastness dyeing is always the hot issue of silk industry. The plenty of tyrosine residue in silk protein may contribute an opportunity to solve this problem. In this paper, in situ coloration of silk is described using coupling reaction between diazonium compounds, made from different arylamine derivatives, and tyrosine residues in the silk fibroin. The spectra of coloured silk and the washing and rubbing fastness were measured. The results suggest that the use of coupling reactions could be developed into a dyeing method for silk. The wet fastness properties of such coloration are good because the chromophores are incorporated into the protein chains.

scholarly journals The in situ generation and reactive quench of diazonium compounds in the synthesis of azo compounds in microreactors

2016 ◽  
Vol 12 ◽  
pp. 1987-2004 ◽  
Author(s):  
Faith M Akwi ◽  
Paul Watts
Keyword(s):  
Continuous Flow ◽  
Coupling Reaction ◽  
Azo Compounds ◽  
Coupling Reactions ◽  
Azo Coupling ◽  
Reaction Conditions ◽  
Flow Rates ◽  
Flow Synthesis ◽  
Optimum Flow

In this paper, a micro-fluidic optimized process for the continuous flow synthesis of azo compounds is presented. The continuous flow synthesis of Sudan II azo dye was used as a model reaction for the study. At found optimal azo coupling reaction temperature and pH an investigation of the optimum flow rates of the reactants for the diazotization and azo coupling reactions in Little Things Factory-MS microreactors was performed. A conversion of 98% was achieved in approximately 2.4 minutes and a small library of azo compounds was thus generated under these reaction conditions from couplers with aminated or hydroxylated aromatic systems. The scaled up synthesis of these compounds in PTFE tubing (i.d. 1.5 mm) was also investigated, where good reaction conversions ranging between 66–91% were attained.

scholarly journals Cross-dehydrogenative coupling for the intermolecular C–O bond formation

2015 ◽  
Vol 11 ◽  
pp. 92-146 ◽  
Author(s):  
Igor B Krylov ◽  
Vera A Vil’ ◽  
Alexander O Terent’ev
Keyword(s):  
Bond Formation ◽  
Coupling Reaction ◽  
Present Review ◽  
Published Data ◽  
Coupling Reactions ◽  
Sulfonic Acids ◽  
Dehydrogenative Coupling ◽  
Starting Compound ◽  
The Cross

The present review summarizes primary publications on the cross-dehydrogenative C–O coupling, with special emphasis on the studies published after 2000. The starting compound, which donates a carbon atom for the formation of a new C–O bond, is called the CH-reagent or the C-reagent, and the compound, an oxygen atom of which is involved in the new bond, is called the OH-reagent or the O-reagent. Alcohols and carboxylic acids are most commonly used as O-reagents; hydroxylamine derivatives, hydroperoxides, and sulfonic acids are employed less often. The cross-dehydrogenative C–O coupling reactions are carried out using different C-reagents, such as compounds containing directing functional groups (amide, heteroaromatic, oxime, and so on) and compounds with activated C–H bonds (aldehydes, alcohols, ketones, ethers, amines, amides, compounds containing the benzyl, allyl, or propargyl moiety). An analysis of the published data showed that the principles at the basis of a particular cross-dehydrogenative C–O coupling reaction are dictated mainly by the nature of the C-reagent. Hence, in the present review the data are classified according to the structures of C-reagents, and, in the second place, according to the type of oxidative systems. Besides the typical cross-dehydrogenative coupling reactions of CH- and OH-reagents, closely related C–H activation processes involving intermolecular C–O bond formation are discussed: acyloxylation reactions with ArI(O2CR)2 reagents and generation of O-reagents in situ from C-reagents (methylarenes, aldehydes, etc.).

Synthesis, Characterization and Catalytic Utilization of a Ferrocene Diamidodiphosphane

2007 ◽  
Vol 72 (4) ◽  
pp. 453-467 ◽  
Author(s):  
Petr Štěpnička ◽  
Jiří Schulz ◽  
Ivana Císařová ◽  
Karla Fejfarová
Keyword(s):  
Phenylboronic Acid ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
Aryl Halides ◽  
Coupling Reactions ◽  
Aryl Chlorides ◽  
Highly Active ◽  
Aryl Bromides ◽  
Cross Coupling Reaction

Amidation of 1'-(diphenylphosphanyl)ferrocene-1-carboxylic acid (Hdpf) with ethane-1,2-diamine afforded N,N'-ethylenebis[1'-(diphenylphosphanyl)ferrocene-1-carboxamide] (1), which was isolated in free and solvated form, 1·2AcOH. Both 1 and Hdpf were further converted to their respective phosphane sulfides, 2·2AcOH and 3 that were structurally characterized. Testing of the amidophosphane ligands in Suzuki-Miyaura cross-coupling reaction between phenylboronic acid and various aryl halides revealed that catalyst formed in situ from 1 and palladium(II) acetate is highly active in coupling reactions of aryl bromides whilst the corresponding aryl chlorides showed no or only poor conversions. The catalyst based on 2·2AcOH gave markedly lower yields of the coupling products.

In situ TEM studies of irradiation effects for materials improvement

1991 ◽  
Vol 49 ◽  
pp. 452-453
Author(s):  
Charles W. Allen
Keyword(s):  
Nuclear Reactor ◽  
Austenitic Stainless Steels ◽  
High Energy ◽  
Point Of View ◽  
In Situ Tem ◽  
Irradiation Effects ◽  
Tem Analysis ◽  
Radiation Induced ◽  
Analytical Tools

Irradiation effects studies employing TEMs as analytical tools have been conducted for almost as many years as materials people have done TEM, motivated largely by materials needs for nuclear reactor development. Such studies have focussed on the behavior both of nuclear fuels and of materials for other reactor components which are subjected to radiation-induced degradation. Especially in the 1950s and 60s, post-irradiation TEM analysis may have been coupled to in situ (in reactor or in pile) experiments (e.g., irradiation-induced creep experiments of austenitic stainless steels). Although necessary from a technological point of view, such experiments are difficult to instrument (measure strain dynamically, e.g.) and control (temperature, e.g.) and require months or even years to perform in a nuclear reactor or in a spallation neutron source. Consequently, methods were sought for simulation of neutroninduced radiation damage of materials, the simulations employing other forms of radiation; in the case of metals and alloys, high energy electrons and high energy ions.

Sign in / Sign up

Export Citation Format

Share Document