5392-40-5Relevant articles and documents
Effective chromium-mediated oxidation of allylic and benzylic alcohols by sodium percarbonate
Muzart, Jacques,Ajjou, Abdelaziz N'Ait,Ait-Mohand, Samia
, p. 1989 - 1990 (1994)
High selectivity to the corresponding ketones and aldehydes has been observed for the title reaction when performed in 1,2-dichloroethane at 80°C in the presence of catalytic amounts of pyridinium dichromate and Adogen 464. The oxidation of unactivated alcohol was less efficient under these conditions.
Supported ionic liquid phase catalysis for aerobic oxidation of primary alcohols
Chrobok, Anna,Baj, Stefan,Pud?o, Wojciech,Jarz?bski, Andrzej
, p. 179 - 185 (2010)
The copper-TEMPO-catalysed aerobic oxidation of primary alcohols based on the new supported ionic liquid phase (SILP) catalysts is presented. CuCl 2 acts as a homogenous catalyst dissolved in the small quantity of ionic liquid dispersed in the form of film on the solid support. A bi-modal pore structure silica with a highly developed surface and an ionogel were used as solid supports. 1-Butyl-3-methylimidazolium octylsulfate as the most active catalyst-philic phase was found. The application of SILP catalysts for the oxidation of alcohols allows the high yields of corresponding aldehydes (92-95%). The catalysts were used in seven cycles without significant loss of activity. High recoveries of the catalysts were observed.
Waste-free electrochemical oxidation of alcohols in water
Palmisano, Giovanni,Ciriminna, Rosaria,Pagliaro, Mario
, p. 2033 - 2037 (2006)
We describe a new sol-gel molecular electrode made of a thin layer of organosilica doped with the nitroxyl radical TEMPO (2,2,6,6- tetramethylpiperidine-1-oxyl) electrodeposited on the surface of an ITO-coated glass and its employment as a selective and versatile oxidation catalyst in the electrochemical conversion of different alcohols to carbonyl compounds. Environmentally friendly water or a water/acetonitrile mixture buffered with bicarbonate is used as solvent. The electrode is highly stable and it can be reused for a prolonged period of time allowing easy separation from the products.
Method for preparing citral through dehydrolinalool rearrangement reaction
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Paragraph 0023; 0024; 0025; 0026; 0027, (2021/08/14)
The invention discloses a method for synthesizing citral by rearranging dehydrolinalool serving as a raw material. The method comprises the following steps: adding a catalytic system MoO2(acac)2 and Ph3PO into dehydrolinalool serving as the raw material in the presence of a solvent methylbenzene and an organic acid 4-tert-butylbenzoic acid, and catalyzing Meyer-Schuster rearrangement reaction to obtain citral. The catalyst system used in the invention can obtain citral with relatively high activity and selectivity and relatively ideal conversion rate and yield, the reaction process is green and environment-friendly, and harmful and odorous mercaptan and thioether are not generated. The catalytic system provides an improved method for the preparation of citral, avoids the use of sulfoxide compounds, and has a good application prospect.
Transition Metal-Substituted Potassium Silicotungstate Salts as Catalysts for Oxidation of Terpene Alcohols with Hydrogen Peroxide
da Silva, Marcio Jose,da Silva Andrade, Pedro Henrique,Sampaio, Vinicius Fernando Coelho
, p. 2094 - 2106 (2020/11/13)
Abstract: In this work, the catalytic activity of the transition metal-substituted potassium silicotungstate salts (i.e. K8-nSiMn+W11O39 (Mn+ = Cu2+, Co2+, Ni2+, Zn2+ and Fe3+) was investigated on the oxidation reactions of the terpene alcohols with H2O2 aqueous solution. The metal-substituted silicotungstate salts were easily synthesized in one-pot reactions of the precursor metal solutions (i.e. Na2WO4, Na2SiO3 and MCln) with KCl added in stoichiometric amount; after this precipitation step, the solid heteropoly salts were filtered and dried in an oven. This procedure of synthesis avoids multi-step processes that starts from the pristine heteropolyacid. The substituted metal heteropoly salts were characterized by infrared spectroscopy, measurements of the specific surface area (BET) and porosimetry by isotherms of adsorption/desorption of N2, X-rays diffraction, thermal analyses, dispersive X-rays spectroscopy, scanning electronic microscopy. The acidity strength was estimated by potentiometric titration with n-butylamine. All the salts were evaluated as catalysts in terpenic alcohols oxidation reactions with H2O2. The K5SiFeW11O39 was the most active and selective catalyst toward oxidation products. The impacts of the main reaction variables such as catalyst concentration, temperature, oxidant load, and nature of the terpene substrate were assessed. The highest activity of the K5SiFeW11O39 catalyst was assigned to the highest Lewis acidity. Graphic Abstract: [Figure not available: see fulltext.].
Homogeneous CuCl2/TMEDA/TEMPO-Catalyzed chemoselective base- and halogen- free aerobic oxidation of primary alcohols in mild conditions
Alves, Otávio A. L.,Chagas, Rafael C. R.,Princival, Jefferson L.,Ribeiro, RogérioT.,Silva, Emmanuel D.,Villar, José A. F. P.
, (2021/08/03)
This article describes the developing of a base- and halogen- free homogeneous system aiming to chemoselectively oxidize allyl, furyl, aryl and heteroaryl primary alcohols. The current easy-to-handle aerobic system uses few amounts of CuCl2/TMEDA/TEMPO system under mild reaction conditions to produce aldehydes in high yields. Moreover, the CuCl2/TMEDA cyclic voltammetry was measured for the first time, disclosing that TMEDA as ligand substantially affects the redox potential (E1/2) of the couple E1/2Cu2+/Cu+ to E1/2Cu2+/Cu+-TMEDA by 454 mV in the redox system.
Zwitterion-induced organic-metal hybrid catalysis in aerobic oxidation
Hu, Rong-Bin,Lam, Ying-Pong,Ng, Wing-Hin,Wong, Chun-Yuen,Yeung, Ying-Yeung
, p. 3498 - 3506 (2021/04/07)
In many metal catalyses, the traditional strategy of removing chloride ions is to add silver salts via anion exchange to obtain highly active catalysts. Herein, we reported an alternative strategy of removing chloride anions from ruthenium trichloride using an organic [P+-N-] zwitterionic compound via multiple hydrogen bond interactions. The resultant organic-metal hybrid catalytic system has successfully been applied to the aerobic oxidation of alcohols, tetrahydroquinolines, and indolines under mild conditions. The performance of zwitterion is far superior to that of many other common Lewis bases or Br?nsted bases. Mechanistic studies revealed that the zwitterion triggers the dissociation of chloride from ruthenium trichloride via nonclassical hydrogen bond interaction. Preliminary studies show that the zwitterion is applicable to catalytic transfer semi-hydrogenation.
An isocyanide ligand for the rapid quenching and efficient removal of copper residues after Cu/TEMPO-catalyzed aerobic alcohol oxidation and atom transfer radical polymerization
Bulska, Ewa,Enciso, Alan E.,Fantin, Marco,Grela, Karol,Lorandi, Francesca,Matyjaszewski, Krzysztof,Nogas, Wojciech,Piatkowski, Jakub,Ruszczynska, Anna,Szczepaniak, Grzegorz,Yerneni, Saigopalakrishna S.
, p. 4251 - 4262 (2020/05/13)
Transition metal catalysts play a prominent role in modern organic and polymer chemistry, enabling many transformations of academic and industrial significance. However, the use of organometallic catalysts often requires the removal of their residues from reaction products, which is particularly important in the pharmaceutical industry. Therefore, the development of efficient and economical methods for the removal of metal contamination is of critical importance. Herein, we demonstrate that commercially available 1,4-bis(3-isocyanopropyl)piperazine can be used as a highly efficient quenching agent (QA) and copper scavenger in Cu/TEMPO alcohol aerobic oxidation (Stahl oxidation) and atom transfer radical polymerization (ATRP). The addition ofQAimmediately terminates Cu-mediated reactions under various conditions, forming a copper complex that can be easily separated from both small molecules and macromolecules. The purification protocol for aldehydes is based on the addition of a small amount of silica gel followed byQAand filtration. The use ofQA?SiO2synthesizedin situresults in products with Cu content usually below 5 ppm. Purification of polymers involves only the addition ofQAin THF followed by filtration, leading to polymers with very low Cu content, even after ATRP with high catalyst loading. Furthermore, the addition ofQAcompletely prevents oxidative alkyne-alkyne (Glaser) coupling. Although isocyanideQAshows moderate toxicity, it can be easily converted into a non-toxic compound by acid hydrolysis.
Oxidation of alcohols using an oxoammonium salt bearing the nitrate anion
Miller, Shelli A.,Sandoval, Arturo León,Leadbeater, Nicholas E.
supporting information, (2019/12/25)
A methodology for the oxidation of alcohols to the corresponding carbonyl compounds is reported using a sub-stoichiometric quantity of an oxoammonium salt bearing the nitrate counterion. The approach proves successful for the oxidation of a range of alcohol substrates including those bearing an oxygen atom β to the site of oxidation or an α-trifluoromethyl moiety. The mechanism of the reaction has been probed and also gives an insight into the previously reported nitric acid mediated oxidation of alcohols.
Preparation method of natural citral
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Paragraph 0041-0056, (2020/03/09)
The invention discloses a preparation method of natural citral, and belongs to the technical field of natural perfume synthesis. The preparation method comprises following steps: (1) adding a pcc reagent into a reactor, adding a proper solvent, and evenly stirring to obtain a mixed solution; (2) dropwise adding natural linalool, wherein the mass ratio of linalool to the pcc reagent is 1:3-6, and after addition, carrying out reactions for 2 to 4 hours; (3) stopping reactions, adding a water solution of sodium sulfite to quench the reactions, separating an organic layer from the reaction product, extracting the water layer by a solvent, merging the organic phases, adjusting the pH value of the organic phase by a water solution of sodium hydrogen carbonate, and collecting the organic layer; and (4) washing the organic layer, drying, and carrying out rectification to obtain natural citral. The adopted raw material namely natural linalool is easily available; and then linalool is oxidized by pcc to obtain natural citral, which is more pure and has a higher content. The natural citral meets the nature requirement of the North America market.
