XnRelevant articles and documents
All total 484 Articles be found
All total 484 Articles be foundCubic CuxZrO100-x as an efficient and selective catalyst for the oxidation of aromatics active methyl, alcohol, and amine groups
Bankar, Balasaheb D.,Advani, Jacky H.,Biradar, Ankush V.
, (2021)
The local structure of a supported active metal plays a vital role in determining the desired product's selectivity in heterogeneous catalysis. Herein, we have developed a simple protocol for the synthesis of Cu doped on cubic ZrO2 mixed metal oxide catalysts and used it for the selective oxidation of various functional groups. The catalyst was synthesized by varying the wt.% of Cu (1–20%) on ZrO2 by co-precipitation, followed by hydrothermal treatment. The X-ray diffraction pattern of the catalysts confirmed the formation of the cubic phase of ZrO2, and the growth of CuO occurred along the (1 1 1) plane. The microscopy analysis revealed the uniform distribution of Cu on the ZrO2 surface, while XPS analysis confirmed the presence of copper in the +2 oxidation state. The synthesized catalyst with 2 wt% loading of Cu on ZrO2 showed excellent liquid-phase oxidation properties and gave good to best conversion of active methyl groups, alcohols, and amines with high selectivities to corresponding ketones, aldehydes, and amides, respectively, under milder reaction conditions. Furthermore, the synthesized catalyst showed a broader substrate scope for the various substituted active methyl groups, alcohols, and amines with good conversion and selectivity.
Oxidation of oximes to ketones with zeolite supported permanganate
Jadhav,Wadgaonkar,Joshi,Salunkhe
, p. 1989 - 1995 (1999)
A variety of aldoximes and ketoximes are oxidised to corresponding aldehydes and ketones in excellent yields by zeolite supported permanganate.
Polyoxometalate-Incorporated Framework as a Heterogeneous Catalyst for Selective Oxidation of C-H Bonds of Alkylbenzenes
Hu, Xin,Ma, Pengtao,Niu, Jingyang,Wang, Hui,Wang, Jingping,Wang, Quanzhong,Wang, Yingyue,Xu, Baijie
, p. 7753 - 7761 (2021)
Developing new catalysts for highly efficient and selective oxidation of saturated C-H bonds is significant due to their thermodynamic strength. Via incorporation of PW12O403-, pyridine-2,5-dicarboxylic acids (pydc), and Fe(III) ions into one framework, a new polyoxometalate-based metal-organic framework, [HFe4O2(H2O)4(pydc)3PW12O40]·10.5H2O (FeW-PYDC), was successfully prepared by a hydrothermal method. Interestingly, FeW-PYDC features a three-dimensional porous structure with {Fe4O2} interconnecting with PW12O403- units. FeW-PYDC displayed excellent performance in the selective oxidation of C-H bonds of alkylbenzenes with high conversion (95.7%) and selectivity (96.6%). As an effective heterogeneous catalyst, FeW-PYDC demonstrates good reusability and structural stability.
Organotellurium-catalyzed oxidative deoximation reactions using visible-light as the precise driving energy
Deng, Xin,Qian, Rongrong,Zhou, Hongwei,Yu, Lei
, p. 1029 - 1032 (2021)
Irradiated by visible light, the recyclable (PhTe)2-catalyzed oxidative deoximation reaction could occur under mild conditions. In comparison with the thermo reaction, the method employed reduced catalyst loading (1 mol% vs. 2.5 mol%), but afforded elevated product yields with expanded substrate scope. This work demonstrated that for the organotellurium-catalyzed reactions, visible light might be an even more precise driving energy than heating because it could break the Te–Te bond accurately to generate the active free radical catalytic intermediates without damaging the fragile substituents (e.g., heterocycles) of substrates. The use of O2 instead of explosive H2O2 as oxidant affords safer reaction conditions from the large-scale application viewpoint.
Deprotection of dithioacetals with 30% hydrogen peroxide catalyzed by tantalum(V) chloride-sodium iodide or niobium(V) chloride-sodium iodide
Kirihara, Masayuki,Noguchi, Takuya,Okajima, Nobuhiro,Naito, Sayuri,Ishizuka, Yuki,Harano, Aiko,Tsukiji, Hiroyuki,Takizawa, Ryu
, p. 1515 - 1520 (2012)
The reaction of dithioacetals with 30% hydrogen peroxide in the presence of catalytic amounts of tantalum(V) and iodide ion effectively produced carbonyl compounds in high yields. Dithioacetals also can be deprotected using the niobium(V) catalyzed oxidation of iodide ion by hydrogen peroxide under mild conditions.
A mild and versatile method for the oxidative cleavage of oximes and tosylhydrazones to carbonyl compounds
Bose, D. Subhas,Srinivas
, p. 977 - 978 (1998)
1-Hydroxy-1,2-benziodoxol-3(1H)-one 1-oxide (IBX) was found to be an efficient and selective reagent for the mild oxidative cleavage of the C=N of oximes and tosylhydrazones to yield their corresponding carbonyl compounds rapidly at room temperature in high yields.
Zeolite-catalyzed oxidation of benzylic and acetylenic alcohols with t-butyl hydroperoxide
Palombi, Laura,Arista, Luca,Lattanzi, Alessandra,Bonadies, Francesco,Scettri, Arrigo
, p. 7849 - 7850 (1996)
4 A molecular sieves catalyze the mild conversion of activated secondary alcohols into the corresponding carbonyl compounds with t-butyl hydroperoxide (TBHP).
Sodium nitrite catalyzed aerobic oxidative deoximation under mild conditions
Zhang, Guofu,Wen, Xin,Wang, Yong,Mo, Weimin,Ding, Chengrong
, p. 4665 - 4668 (2011)
A mild, simple process for the effective deoximation of a wide range of ketoximes and aldoximes has been developed, which utilizes available NaNO 2 as the catalyst and molecular oxygen as the green oxidant. Notably Amberlyst-15, which acts as the initiator of NaNO2, can be reused without regeneration. This environmentally benign protocol could provide a valuable synthetic method for practical applications.
Enzymatic Tandem Approach to Knoevenagel Condensation of Acetaldehyde with Acidic Methylene Compounds in Organic Media
Koszelewski, Dominik,Paprocki, Daniel,Madej, Arleta,Borys, Filip,Brodzka, Anna,Ostaszewski, Ryszard
, p. 4572 - 4579 (2017)
A tandem enzyme-catalyzed Knoevenagel reaction with acetaldehyde is presented. A new protocol for the synthesis of the desired products through a tandem process based on the enzymatic hydrolysis and Knoevenagel reaction starting from acetaldehyde precurso
Oxidative removal of acetal protection by the action of KHSO5 and AlCl3 under mild heterogeneous conditions
Mirjalili,Zolfigol,Bamoniri
, p. 761 - 762 (2002)
-
Electrochemical performance of ABNO for oxidation of secondary alcohols in acetonitrile solution
Niu, Pengfei,Liu, Xin,Shen, Zhenlu,Li, Meichao
, (2019)
The ketones was successfully prepared from secondary alcohols using 9-azabicyclo[3.3.1]nonane-N-oxyl (ABNO) as the catalyst and 2,6-lutidine as the base in acetonitrile solution. The electrochemical activity of ABNO for oxidation of 1-phenylethanol was investigated by cyclic voltammetry, in situ Fourier transform infrared spectroscopy (FTIR) and constant current electrolysis experiments. The resulting cyclic voltammetry indicated that ABNO exhibited much higher electrochemical activity when compared with 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) under the similar conditions. A reasonable reaction mechanism of the electrocatalytic oxidation of 1-phenylethanol to acetophenone was proposed. In addition, a series of secondary alcohols could be converted to the corresponding ketones at room temperature in 80-95% isolated yields.
Aerobic alcohol oxidation by ruthenium species stabilized on nanocrystalline magnesium oxide by basic ionic liquids
Kantam, M. Lakshmi,Pal, Ujjwal,Sreedhar,Bhargava, Suresh,Iwasawa, Yasuhiro,Tada, Mizuki,Choudary
, p. 1225 - 1229 (2008)
The selective oxidation of various alcohols into their corresponding aldehydes and ketones was achieved by ruthenium species stabilized on the nanocrystalline magnesium oxide (NAP-MgO) by the incorporation of choline hydroxide, a basic ionic liquid, in excellent yields. The procedure is simple, efficient and environmentally benign. The catalyst can be used for four cycles with almost consistent activity.
Enhanced aqueous oxidation activity and durability of simple manganese(III) salen complex axially anchored to maghemite nanoparticles
Rezaeifard, Abdolreza,Jafarpour, Maasoumeh,Farrokhi, Alireza,Parvin, Sousan,Feizpour, Fahimeh
, p. 64640 - 64650 (2016)
Simple Mn-salen complex was anchored coordinatively to γ-Fe2O3 nanoparticles through amine functionality which provide a new magnetically recoverable nanocatalyst with high oxidation activity and stability. Catalyst characterization was performed using FT-IR, UV-Vis, XRD, EDS, TGA and ICP-AES. TEM image revealed a quasi-spherical structure with size smaller than 20 nm for nanocatalyst. A thermal stability up to around 300 °C was verified for prepared nanocatalyst based on thermogravimetric analysis. Finally, the catalytic performance of magnetically recoverable Mn-catalyst was exploited in the green oxidation of different types of functional groups including olefins, alcohols, saturated hydrocarbons and sulfur containing compounds with n-Bu4NHSO5 (TBAOX) in water under heterogeneous conditions. The salen catalyst proved to be reusable for at least eight times and the oxidant's by-product (n-Bu4NHSO4) could also be recycled.
Vanadium-catalyzed atmosphericoxidation of benzyl alcoholsusing water as Solvent
Kodama, Shintaro,Hashidate, Suguru,Nomoto, Akihiro,Yano, Shigenobu,Ueshima, Michio,Ogawa, Akiya
, p. 495 - 497 (2011)
A vanadium complex combined with 4,4'-di-tert-butyl-2,2'- bipyridyl as a ligand exhibited excellent catalytic activity in atmosphericoxidation of benzhydrolsusing water as solvent to afford benzophenones in good yields.
Highly practical and efficient preparation of aldehydes and ketones from aerobic oxidation of alcohols with an inorganic-ligand supported iodine catalyst
Zhang, Mengqi,Zhai, Yongyan,Ru, Shi,Zang, Dejin,Han, Sheng,Yu, Han,Wei, Yongge
, p. 10164 - 10167 (2018)
Herein, we divulge an efficient protocol for aerobic oxidation of alcohols with an inorganic-ligand supported iodine catalyst, (NH4)5[IMo6O24]. The catalyst system is compatible with a wide range of groups and exhibits high selectivity, and shows excellent stability and reusability, thus serving as a potentially greener alternative to the classical transformations.
Reactions of alcohols with cesium fluoroxysulfate
Stavber, Stojan,Kosir, Iztok,Zupan, Marko
, p. 4916 - 4920 (1997)
The reactions of alcohols with cesium fluoroxysulfate (CsSO4F) in MeCN suspension were studied, and the role of the structure of the alcohol and the reaction conditions on the course of reaction was determined. Secondary benzyl alcohols bearing a nonactivating aromatic ring were selectively oxidized to the corresponding ketones, while the CsSO4F-mediated reaction of phenyl-1-naphthylmethanol resulted in the formation of 1-fluoronaphthalene and benzaldehyde. Cyclic and noncyclic secondary alcohols were readily converted to ketones, as well as 1-hydroxybenzecyclanes to benzocyclanones- 1, without any further fluorination or oxidation under the reaction conditions. On the other hand, reactions of primary alcohols with CsSO4F resulted in the formation of acid fluorides derived from further fluorination of aldehydes. Another type of transformation was observed in the case of alcohols bearing a benzyl functional group attached geminal to a hydroxy group, where decarbanylation of reactive intermediates resulting in the formation of benzyl fluoride derivatives became the main process. 2- Phenylethanol was so converted to benzyl fluoride and phenylacetyl fluoride in a 3:1 relative ratio, while 2-phenyl-1-propanol was selectively transformed to 1-phenyl-1-fluoroethane. The presence of the radical inhibitor nitrobenzene in the reaction mixture considerably inhibited conversion of the starting material. The same effect was observed by lowering the solvent polarity. Hammett correlation analysis of the effect of substituents on the reaction rates of oxidation of a set of substituted 1-phenyl-1-ethanols to acetophenones gave the reaction constant p+ = -0.32, while analysis of analogous data for the transformations of benzyl alcohols to benzoyl fluorides gave the value of -0.54. A mechanism including radical intermediates was proposed for the transformation of alcohols by CsSO4F.
Deprotection of 1,3-dithianes by antimony pentachloride via single electron transfer processes
Kamata,Otogawa,Hasegawa
, p. 7421 - 7424 (1991)
A variety of 1,3-dithianes was converted to the corresponding carbonyl compounds in good yields when those substances were treated with antimony pentachloride in methylene chloride. Single electron transfer from dithianes to antimony pentachloride was proposed as an initiation step of the reaction.
One-pot synthesis of carbamoyl azides directly from primary alcohols and oxidation of secondary alcohols to ketones using iodobenzene dichloride in combination with sodium azide
Li, Xiao-Qiang,Wang, Wei-Kun,Zhang, Chi
, p. 2342 - 2350 (2009)
An effective synthesis of carbamoyl azides directly from primary alcohols using iodobenzene dichloride in combination with sodium azide has been developed. Moreover, the same regent combination was also efficient for the oxidation of secondary alcohols to the corresponding ketones.
Ruthenium(II) Complexes Bearing Schiff Base Ligands for Efficient Acceptorless Dehydrogenation of Secondary Alcohols?
Dong, Qing,Feng, Qi,Han, Zhangang,Hao, Zhiqiang,Lin, Jin,Liu, Kang,Lu, Guo-Liang,Ma, Dongzhu
, p. 121 - 128 (2021)
Four ruthenium(II) complexes 1—4 [RN=CH-(2,4-(tBu)2C6H2O)]RuH(PPh3)2(CO) (R = C6H5, 1; R = 4-MeC6H4, 2; R = 4-ClC6H4, 3; R = 4-BrC6H4, 4) bearing Schiff base ligands were prepared by treating RuHClCO(PPh3)3 with RN=CH-(2,4-(tBu)2C6H2OH (L1—L4) in the presence of triethylamine. Their structures were fully characterized by elemental analysis, IR, NMR spectroscopy and X-ray crystallography. These Ru(II) complexes exhibit high catalytic performance and good functional-group compatibility in the acceptorless dehydrogenation of secondary alcohols, affording the corresponding ketones in 82%—94% yields.
-
Milstein,Stille
, p. 3636 (1978)
-
NHPI and ferric nitrate: A mild and selective system for aerobic oxidation of benzylic methylenes
Miao, Chengxia,Zhao, Hanqing,Zhao, Quanyi,Xia, Chungu,Sun, Wei
, p. 1378 - 1383 (2016)
A mild and selective system comprising N-hydroxyphthalimide (NHPI) and Fe(NO3)3·9H2O was developed for the oxidation of benzylic methylenes with an atmospheric pressure of molecular oxygen at 25°C. The influences of reaction conditions such as solvent, different metal catalysts and catalyst loading were studied, as well as the kinetics of the oxidation reaction. Various benzylic methylene substrates could be oxidized to the corresponding carbonyl compounds in satisfactory yields with this catalytic system. Hammett analysis suggested that the substrates with electron-donating groups would have higher oxidation rates. Isotopic (18O) labeling experiments provided evidence of the participation of the nitrate anion in the catalytic cycle. In addition, a possible radical mechanism involving hydrogen atom abstraction by PINO (phthalimide-N-oxyl) and nitrate participation for the oxidation of benzylic methylenes in the Fe(NO3)3·9H2O/NHPI/O2 system was proposed.
Silica sulfuric acid/wet SiO2 as a novel heterogeneous system for cleavage of carbon nitrogen double bonds under mild conditions
Zolfigol, Mohammad Ali,Poor-Baltork, Iraj Mohammad,Mirjalili, Bibi Fatemeh,Shirini, Farhad,Salehzadeh, Sadegh,Keypour, Hassan,Ghorbani-Choghamarani, Arash,Zebarjadian, Mohammad Hassan,Mohammadi, Kamal,Hazar, Azizeh
, p. 2735 - 2743 (2003)
Silica sulfuric acid in the presence of wet SiO2 was caused to react with oximes, hydrazones, semicarbazones, azines, and Schiff-bases. It was observed that it converts them to their corresponding carbonyl compounds in good to excellent yields under mild and heterogeneous conditions.
-
Gupta,Marathe
, p. 134,135 (1976)
-
Copper-Containing Polyoxometalate-Based Metal-Organic Frameworks as Highly Efficient Heterogeneous Catalysts toward Selective Oxidation of Alkylbenzenes
Li, Dandan,Ma, Xinyi,Wang, Quanzhong,Ma, Pengtao,Niu, Jingyang,Wang, Jingping
, p. 15832 - 15840 (2019)
With a one-pot assembly method, two copper-containing Keggin-type polyoxometalate-based metal-organic frameworks (POMOFs), i.e., [CuI6(trz)6{PW12O40}2] (HENU-2, HENU = Henan University; trz = 1,2,4- triazole) and [CuI3(trz)3{PMo12O40}] (HENU-3), were successfully prepared and structurally characterized. These two compounds, which are generated by the extension of a crown-like {Cu6(trz)6} macrocycle-based sandwich-type structural unit, possess identical noninterpenetration 3D frameworks except for the polyanions difference. Additionally, both of themare assessed as highly effective heterogeneous catalysts in facilitating the oxidation of alkylbenzenes to ketone products in the presence of tert-butyl hydroperoxide. Under optimized conditions, HENU-2 can achieve a 95.2% conversion of diphenylmethane in 20 h with a 100% selectivity toward benzophenone, and it was reused for three runs with constant high activity, which outperforms most POM-based catalysts for this catalytic reaction.
Nanocrystalline magnesium oxide stabilized palladium(0): An efficient reusable catalyst for room temperature selective aerobic oxidation of alcohols
Layek, Keya,Maheswaran,Arundhathi,Kantam, M. Lakshmi,Bhargava, Suresh K.
, p. 606 - 616 (2011)
Nanocrystalline magnesium oxide-stabilized palladium(0) [NAP-Mg-Pd(0)], as an efficient catalytic system has been employed for the selective oxidation of alcohols using atmospheric oxygen as a green oxidant at room temperature. Various alcohols could be transformed into their corresponding aldehydes or ketones in good to excellent yields using a set of optimal conditions. NanoActive Magnesium Oxide Plus, [NAP-MgO] with its three-dimensional structure and well-defined shape acts as an excellent support for well dispersed palladium(0) nanoparticles. This catalyst can be recovered and reused for several cycles without any significant loss of catalytic activity.
Exploration of silicon phthalocyanines as viable photocatalysts for organic transformations
Ayare, Pooja J.,Dickerson, Shelby D.,Vannucci, Aaron K.,Wiskur, Sheryl L.
, (2021/10/01)
Silicon phthalocyanines have been largely ignored as photocatalysts, despite their low energy excitation, long triplet lifetimes, and their ability to form singlet oxygen. By incorporating alkyl and silicon protecting groups as axial ligands on the silico
Rapid, chemoselective and mild oxidation protocol for alcohols and ethers with recyclable N-chloro-N-(phenylsulfonyl)benzenesulfonamide
Badani, Purav,Chaturbhuj, Ganesh,Ganwir, Prerna,Misal, Balu,Palav, Amey
supporting information, (2021/06/03)
Chlorine is the 20th most abundant element on the earth compared to bromine, iodine, and fluorine, a sulfonimide reagent, N-chloro-N-(phenylsulfonyl)benzenesulfonamide (NCBSI) was identified as a mild and selective oxidant. Without activation, the reagent was proved to oxidize primary and secondary alcohols as well as their symmetrical and mixed ethers to corresponding aldehydes and ketones. With recoverable PS-TEMPO catalyst, selective oxidation over chlorination of primary and secondary alcohols and their ethers with electron-donating substituents was achieved. The reagent precursor of NCBSI was recovered quantitatively and can be reused for synthesizing NCBSI.
