104-87-0Relevant articles and documents
Au-Carbon Electronic Interaction Mediated Selective Oxidation of Styrene
Liu, Ben,Wang, Pu,Lopes, Aaron,Jin, Lei,Zhong, Wei,Pei, Yong,Suib, Steven L.,He, Jie
, p. 3483 - 3488 (2017)
The rational design of the Au-support electronic interaction is crucial for Au nanocatalysis. We herein report our observation of electronic perturbation at the Au-carbon interface and its application in controlling the reaction selectivity in styrene oxidation. Ultrasmall Au nanocatalysts were grown in situ on a nitrided carbon support where the nitrogen-doped carbon supports enriched the surface charge density and generated electron-rich Au surface sites. The Au-carbon interaction altered the binding behavior of C=C bonds to catalytic centers, leading to a solvent-polarity-dependent selectivity in C=C oxidation reactions. A high selectivity of 90% to benzaldehyde was achieved in an apolar solvent, and a selectivity of 95% to styrene epoxide was attained in a polar solvent. The Au-carbon electronic perturbation, originating from surface functional groups on the carbon support, may provide an alternative avenue to tune the selectivity and activity of more complex reactions in heterogeneous catalysis.
Clay-anchored non-heme iron-salen complex catalyzed cleavage of C{double bond, long}C bond in aqueous medium
Dhakshinamoorthy, Amarajothi,Pitchumani, Kasi
, p. 9911 - 9918 (2006)
Clay-anchored iron[N,N′-ethylenebis(salicylideneaminato)] complex, synthesized by direct exchange, oxidizes various olefins and chalcones in aqueous acetonitrile using hydrogen peroxide as terminal oxidant. Aldehyde and its derivatives are obtained as oxidation products by the cleavage of C{double bond, long}C double bond. In comparison with the catalysis by iron-salen complex in solution, the clay catalyzed pathway not only increases the rate of reaction significantly, but also provides selective oxidation toward the aldehyde. Some chalcones also give very good yield in water, compared to the solution and clay catalyzed pathways.
Convenient one-pot synthesis of aldehydes from carboxylic acid chlorides with sodium diethyldihydroaluminate
Yoon,Choi,Gyoung,Jun
, p. 1775 - 1781 (1993)
Carboxylic acid chlorides and acids were converted into the corresponding aldehydes conveniently in one-pot process with sodium diethyldihydroaluminate (SDDA) in moderate to good yields.
Hexadecylphosphate-functionalized iron oxide nanoparticles: Mild oxidation of benzyl C-H bonds exclusive to carbonyls by molecular oxygen
Li, Lei,Lv, Jiangang,Shen, Yi,Guo, Xuefeng,Peng, Luming,Xie, Zaiku,Ding, Weiping
, p. 2746 - 2752 (2014)
We report here a specially designed catalytic system consisting of hexadecylphosphate-functionalized iron oxide nanoparticles in oil/water biphasic emulsion. The iron oxide nanoparticles act as catalytic centers and the surface-bonded hexadecylphosphates as peripheral units which tune the activity of iron oxide and the access of reactants to the catalytic centers. The catalytic system is highly effective to oxidize the benzyl C-H bonds in a series of compounds to carbonyls exclusively by molecular oxygen under mild conditions. The catalytic process, green and low cost, offers a novel concept to design highly effective catalysts with nanoparticles as active centers and surface-bonded organic phosphates as accelerants for oxidation reactions.
FeCl3-catalyzed oxidative decarboxylation of aryl/heteroaryl acetic acids: Preparation of selected API impurities
Gangadurai, Chinnakuzhanthai,Illa, Giri Teja,Reddy, D. Srinivasa
, p. 8459 - 8466 (2020)
There is an ever-increasing demand for impurity compounds for use in impurity profiling as regulatory agencies seek information during registration. Herein, we report the FeCl3-catalyzed oxidative decarboxylation of aryl- and heteroaryl acetic acids to the corresponding carbonyl compounds. A variety of useful aldehydes and ketones were prepared in a simple one-pot transformation by employing an environmentally benign, low-cost, and readily available iron salt. The utility of this method has been demonstrated by preparing five valuable API impurities including a multi-gram-scale synthesis of ketorolac impurity B for the first time. This journal is
Ruthenium(ii)-supported phosphovanadomolybdates [Ru(dmso)3PMo6V3O32]6-and [Ru(PMo6V3O32)2]14-, and their use as heterogeneous catalysts for oxidation of alcohols
Shi, Hao-Yu,Zhou, Wen-Yan,Song, Xiao-Ming,Jia, Ai-Quan,Shi, Hua-Tian,Zhang, Qian-Feng
, p. 1551 - 1555 (2021)
Self-assembly of cis-[RuCl2(dmso)4], NaVO3, Na2MoO4 and NaH2PO4 in a molar ratio of 1?:?3?:?6?:?1 in HOAc-NaOAc buffer (pH = 4-5) in the presence of CsCl gave a ruthenium(ii)-supported phosphovanadomolybdate [RuII(dmso)3PMoVI6VV3O32]6- (1). While a similar reaction with the reactants in a molar ratio of 1?:?6?:?12?:?2 afforded a ruthenium substituted "sandwich"type polyoxometalate [RuII(PMoVI6VV3O32)2]14- (2). Clusters 1 and 2 were well characterized by single-crystal X-ray diffraction. Their use as heterogeneous catalysts for oxidation of alcohols in the presence of molecular oxygen was also investigated.
Selective Visible Light Aerobic Photocatalytic Oxygenation of Alkanes to the Corresponding Carbonyl Compounds
Somekh, Miriam,Khenkin, Alexander M.,Herman, Adi,Neumann, Ronny
, p. 8819 - 8824 (2019)
The aerobic, selective oxygenation of alkanes via C-H bond activation is an important research challenge. Photocatalysis offers the potential for the introduction of additional concepts for such reactions. Visible light photoactive semiconductors such as bismuth oxyhalides (BiOX, X = Cl and Br) used in this research typically oxidize organic compounds through photocatalyzed formation of strongly oxidizing holes. The reactive oxygen species formed react with organic compounds in one-electron processes, leading to radical intermediates and nonselective oxidation. Such oxidation reactions generally lead to total oxidation. Here, impregnation of BiOX with a polyoxometalate, H5PV2Mo10O40, as a strong electron acceptor changed the reactivity of BiOX, leading to Mars-van Krevelen-type reactivity, that is, photoactivated oxygen donation from BiOX to the organic substrate followed by reoxidation by O2 and catalysis. This conclusion was supported by mechanistic studies involving isotope labeling studies. In this way, ethane was selectively oxidized to acetaldehyde in a flow reactor with a turnover number (24 h) of 415.
Palladium-catalyzed reductive carbonylation of aryl triflates with synthesis gas
Brennfuhrer, Anne,Neumann, Helfried,Beller, Matthias
, p. 2537 - 2540 (2007)
A general palladium-catalyzed reductive carbonylation of aryl triflates in the presence of synthesis gas (CO/H2) has been developed. The reaction with this most simple and environmentally benign formylation source proceeds under mild conditions and various aromatic aldehydes have been prepared in good to high yield. Georg Thieme Verlag Stuttgart.
Cu(II) complexes of N-rich aroylhydrazone: Magnetism and catalytic activity towards microwave-assisted oxidation of xylenes
Sutradhar, Manas,Roy Barman, Tannistha,Alegria, Elisabete C. B. A.,Guedes Da Silva, M. Fátima C.,Liu, Cai-Ming,Kou, Hui-Zhong,Pombeiro, Armando J. L.
, p. 12839 - 12849 (2019)
The new aroylhydrazone N-(di(pyridin-2-yl)methylene)pyrazine-2-carbohydrazide (HL) species, rich in N-donor sites, has been used to synthesize Cu(ii) compounds with different nuclearities, viz. the binuclear [Cu2(μ-1κN3,2κN2O-L)(Cl)3(MeOH)] (1), the octanuclear [Cu4(μ-1κN3,2κN2O-L)2(μ-Cl)3(Cl)3]2 (2) and the 1D coordination polymer [Cu3(μ3-1κN3,2κN2O,3κN-L)(μ-NO3)(NO3)3(H2O)3]n·nNO3 (3). They have been characterized by elemental analysis, FT-IR and single crystal X-ray diffraction. The magnetic properties of 2 and 3 have been explored using variable temperature magnetic measurements. The catalytic performances of the compounds were evaluated towards the peroxidative oxidation of o-, p- A nd m-xylenes under microwave irradiation, leading to the formation of the corresponding methyl benzyl alcohol, tolualdehyde and toluic acid as the major products. Complex 3 exhibits the best catalytic activity towards the oxidation of p-xylene with a total yield of 37% (4-methylbenzyl alcohol + p-tolualdehyde + p-toluic acid).
Dodecatungstophosphoric acid (H3PW12O40): A novel and efficient recyclable catalyst for synthesis of 1,1-diacetates from aromatic aldehydes in solvent-free system and their deprotection
Heravi, Majid M.,Derikvand, Fatemeh,Bamoharram, Fatemeh F.
, p. 3109 - 3115 (2006)
A facile and efficient method for the formation of 1,1-diacetates from a variety of aldehydes in the presence of a catalytic amount of H 3PW12O40 and acetic anhydride was achieved in good yields at room temperature. The deprotection of the resulting acylals is achieved using the same catalyst in acetone. Copyright Taylor & Francis Group, LLC.
TEMPO-based ionic liquid with temperature-dependent property and application for aerobic oxidation of alcohols
Zhu, Jie,Wang, Peng-Cheng,Ming, Lu
, p. 1871 - 1881 (2013)
A novel temperature-dependent ionic liquid based on 2,2,6,6- tetramethylpiperidine-1-oxyl and polyethylene glycol 600 was developed and used in oxidation of alcohols. Various alcohols were oxidized into their corresponding aldehydes or ketones with good yield and selectivity. Owing to the temperature-dependent property of the catalyst, easy recovery was achieved by simple decantation. Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications to view the free supplemental file.
Environmentally Benign Oxidations of Alkenes and Alcohols to Corresponding Aldehydes over Anchored Phosphotungstates: Effect of Supports as Well as Oxidants
Singh, Sukriti,Patel, Anjali
, p. 1059 - 1072 (2016)
Series of catalysts comprising of parent phosphotungstate (PW12) and mono lacunary phosphotungstate (PW11) anchored to different mesoporous materials (MCM-41 and MCM-48) were prepared. Environmentally benign oxidation of alkenes and alcohols were carried out with H2O2 and molecular oxygen as oxidants. The influence of different parameters on the conversion as well as the selectivity was investigated. Comparative study was ascertained over anchored parent, lacunary phosphotungstates as active species and the supports. The kinetic and thermodynamic studies were correlated with the effect of support as well as active species. Moreover, the catalysts could be recovered and reused four times without significant loss in their activity and selectivity. Graphical Abstract: [Figure not available: see fulltext.]
Synthesis of C4 and C8 Chemicals from Ethanol on MgO-Incorporated Faujasite Catalysts with Balanced Confinement Effects and Basicity
Zhang, Lu,Pham, Tu N.,Faria, Jimmy,Santhanaraj, Daniel,Sooknoi, Tawan,Tan, Qiaohua,Zhao, Zheng,Resasco, Daniel E.
, p. 736 - 748 (2016)
A new type of catalyst has been designed to adjust the basicity and level of molecular confinement of KNaX faujasites by controlled incorporation of Mg through ion exchange and precipitation of extraframework MgO clusters at varying loadings. The catalytic performance of these catalysts was compared in the conversion of C2 and C4 aldehydes to value-added products. The product distribution depends on both the level of acetaldehyde conversion and the fraction of magnesium as extraframework species. These species form rather uniform and highly dispersed nanostructures that resemble nanopetals. Specifically, the sample containing Mg only in the form of exchangeable Mg2+ ions has much lower activity than those in which a significant fraction of Mg exists as extraframework MgO. Both the (C6+C8)/C4 and C8/C6 ratios increase with additional extraframework Mg at high acetaldehyde conversion levels. These differences in product distribution can be attributed to 1) higher basicity density on the samples with extraframework species, and 2) enhanced confinement inside the zeolite cages in the presence of these species. Additionally, the formation of linear or aromatic C8 aldehyde compounds depends on the position on the crotonaldehyde molecule from which abstraction of a proton occurs. In addition, catalysts with different confinement effects result in different C8 products.
Mild and efficient deprotection of 1,3-dithianes with N,N′-diiodo-N, N′-1,2-ethanediyl-bis(p-toluenesulphonamide)
Ghorbani-Vaghei, Ramin,Zolfigol, Mohammad Ali
, p. 327 - 330 (2005)
Aliphatic and aromatic 1,3-dithiane are oxidized to the corresponding carbonyl compounds in good yields under mild conditions by N,N′-diiodo-N, N′-1,2-ethanediyl-bis(p-toluenesulphonamide) [NIBTSl and silver nitrate.
Confined Pyrolysis within Metal-Organic Frameworks to Form Uniform Ru3 Clusters for Efficient Oxidation of Alcohols
Ji, Shufang,Chen, Yuanjun,Fu, Qiang,Chen, Yifeng,Dong, Juncai,Chen, Wenxing,Li, Zhi,Wang, Yu,Gu, Lin,He, Wei,Chen, Chen,Peng, Qing,Huang, Yu,Duan, Xiangfeng,Wang, Dingsheng,Draxl, Claudia,Li, Yadong
, p. 9795 - 9798 (2017)
Here we report a novel approach to synthesize atomically dispersed uniform clusters via a cage-separated precursor preselection and pyrolysis strategy. To illustrate this strategy, well-defined Ru3(CO)12 was separated as a precursor by suitable molecular-scale cages of zeolitic imidazolate frameworks (ZIFs). After thermal treatment under confinement in the cages, uniform Ru3 clusters stabilized by nitrogen species (Ru3/CN) were obtained. Importantly, we found that Ru3/CN exhibits excellent catalytic activity (100% conversion), high chemoselectivity (100% for 2-aminobenzaldehyde), and significantly high turnover frequency (TOF) for oxidation of 2-aminobenzyl alcohol. The TOF of Ru3/CN (4320 h-1) is about 23 times higher than that of small-sized (ca. 2.5 nm) Ru particles (TOF = 184 h-1). This striking difference is attributed to a disparity in the interaction between Ru species and adsorbed reactants.
Hydrothermal synthesis of dimeric lanthanide compounds: X-ray structure, magnetic study and heterogeneous catalytic epoxidation of olefins
Sen, Rupam,Hazra, Dipak K.,Koner, Subratanath,Helliwell, Madeleine,Mukherjee, Monika,Bhattacharjee, Ashis
, p. 3183 - 3191 (2010)
A series of dimeric lanthanide carboxylato complexes [La(5-Br-NIC) 3(H2O)2]2·H2O (1); [Gd(5-Br-NIC)3(H2O)2]2 (2), [5-Br-NIC = 5-bromonicotinate] and [Sm(NIC)3(H2O) 2]2 (3) [NIC = nicotinate], have been hydrothermally synthesized and structurally characterized by single crystal X-ray analysis. Complexes 1, 2 and 3 are of similar structure and consist of a basic unit [La(carboxylato)3(H2O)2]2. In compound 1 lanthanide cation is surrounded by one chelating 5-bromo-nicotinato ligand, two bridging oxygen atoms from 5-bromo-nicotinato and two water molecules, in which each La(III) ion is nine coordinated in a tricapped prismatic geometry. However, in compounds 2 and 3 four carboxylate groups link a pair of lanthanide atoms in the O,O′-bridging mode to generate a paddle-wheel-like centrosymmetric dimer. All the compounds exhibit excellent catalytic performance in olefin epoxidation reaction. The variable temperature magnetic susceptibility measurements showed that the magnetic interaction in [Gd(5-Br-NIC)3(H2O)2]2 (2), is antiferromagnetic (J = -0.048 cm-1), while compound [Sm(NIC) 3(H2O)2]2 (3), showed a complicated low-temperature magnetic property.
SbCl5 Complexes of Pyridine N-Oxide and Trimethylamine Oxide as the Oxidizing Agent
Yamamoto, Jiro,Murakami, Mitushige,Kameoka, Noriaki,Otani, Norio,Umezu, Masahiro,Matsuura, Teruo
, p. 345 - 346 (1982)
A 1:1 complex of pyridine N-oxide or trimethylamine oxide with SbCl5 acted as an oxidizing agent to benzyl alcohol, benzoin, furoin, and thiophenols more easily than via the oxides to give benzaldehyde, benzil, furil, and the corresponding disulfides respectively.The trimethylamine oxide-SbCl5 also oxidized p-xylene to p-tolualdehyde under nitrogen and to p-toluic acid under air.
Benzylic oxidation and photooxidation by air in the presence of graphite and cyclohexene
Sereda, Grigoriy,Rajpara, Vikul
, p. 3417 - 3421 (2007)
Graphite is introduced as a convenient catalyst for cyclohexene-promoted photooxidation of p-xylene, ethylbenzene, and cumene by air. Availability of the reagent (air), lack of chemical waste, low toxicity, and reusability of the catalyst make the process a good green alternative of oxidation of these industrially important hydrocarbons.
Quinolinium fluorochromate: An efficient and convenient reagent for oxidative cleavage of thioacetals to their parent carbonyl compounds
Tajbakhsh, Mahmood,Alimohammadi, Kamal,Ramzanian-Lehmali, Farhad,Barghamadi, Mohamad,Shakeri, Alireza
, p. 2587 - 2591 (2005)
Deprotection of thioacetals to their parent carbonyl compounds in high yields has been carried out using quinolinium fluorochromate under mild conditions. Copyright Taylor & Francis Inc.
Morphology dependant oxidation of aromatic alcohols by new symmetrical copper(II) metallatriangles formed by self-assembly of a shared bis-benzimidazolyl diamide ligand
Mahiya, Kuldeep,Mathur, Pavan
, p. 36 - 44 (2013)
A new bis-benzimidazole-based diamide ligand N2,N 2′-bis((1H-benzo[d]imidazol-2-yl)methyl)-[1,1′-biphenyl] -2,2′-dicarboxamide, L and its three Cu(II) metallatriangles of general formula [Cu3(L)3X3]·3X·nH 2O (where X = Cl, Br, NO3) have been synthesized and one of them is structurally characterized. X-ray diffraction work reveals that the metallatriangle [Cu3(L)3Cl3] ·3Cl·15H2O crystallizes in trigonal R3? space group with two independent molecules in the asymmetric unit. The asymmetric unit contains only one-third of the molecules and the rest are generated by the crystallographic 3? axis. Each copper(II) ion adopts a highly distorted square pyramidal geometry. The copper(II) metallatriangles are used as catalyst to carry out the oxidation of substituted benzyl alcohols heterogeneously, in the presence of tert-butyl hydroperoxide. Interestingly, the ratio of product profile and the percentage conversion of the products changes with the surface morphology of the metallatriangle employed as a catalyst. A kite type morphology is found to be highly selective to the formation of acid product over the aldehyde, while a hexagonal type morphology results in a mixed acid + aldehyde product. The initial rate of formation of the aldehyde is found to be almost independent of the amount of catalyst employed.
Selective reduction of hydroxy carbonyl to carbonyl compounds with trialkylborane/trifluoromethanesulfonic acid
Olah,Wu
, p. 407 - 408 (1991)
Triethyl- or triisopropylborane/trifluoromethanesulfonic (triflic) acid is a convenient reagent for the selective reduction of hydroxy substituted carboxylic acids, ketones and aldehydes to yield the corresponding carbonyl compounds. The scope of the reaction, experimental conditions and suggested mechanism are discussed.
Allyltriphenylphosphonium Peroxodisulfate (CH2=CHCH 2PPh3)2S2O8: An Efficient and Convenient Reagent for the Oxidation of Alcohols and Silyl and THP-Ethers under Nonaqueous Conditions
Tajbakhsh,Lakouraj,Fadavi
, p. 1173 - 1181 (2004)
The preparation of allyltriphenylphosphonium peroxodisulfate (ATPPD) as a new and efficient reagent for the oxidation of primary and secondary alcohols, trimethylsilyl and tetrahydropyranyl (THP) ethers to their corresponding carbonyl compounds in refluxing acetonitrile with 1.1:1 molar equivalents of the oxidant is described.
Selective Oxygenation of Ring-Substituted Toluenes with Electron-Donating and -Withdrawing Substituents by Molecular Oxygen via Photoinduced Electron Transfer
Ohkubo, Kei,Suga, Kyou,Morikawa, Kohei,Fukuzumi, Shunichi
, p. 12850 - 12859 (2003)
A ring-substituted toluene with an electron-withdrawing substituent, p-tolunitrile, is oxygenated by molecular oxygen to yield the corresponding aldehyde with tetrafluoro-p-dicyanobenzene as a photocatalyst under photoirradiation with an Hg lamp (λ > 300 nm). The oxygenation of a ring-substituted toluene with an electron-donating substituent, p-xylene, by molecular oxygen is also achieved with 10-methyl-9-phenylacridinium ion as a photocatalyst under visible light irradiation, yielding p-tolualdehyde exclusively as the final oxygenated product. Both the oxygenation reactions are initiated by photoinduced electron transfer from the ring-substituted toluene to the singlet excited state of the photocatalyst. The reason for the high selectivity in the photocatalytic oxygenation of various toluene derivatives by molecular oxygen is discussed on the basis of the photoinduced electron transfer mechanism that does not involve the autoxidation process (radical chain reactions). The reactive intermediates in the photocatalytic cycle are successfully detected as the transient absorption spectra and the electron spin resonance spectra.
Iron oxide functionalised MIL-101 materials in aqueous phase selective oxidations
Balu, Alina Mariana,Lin, Carol Sze Ki,Liu, Hongli,Li, Yingwei,Vargas, Carolina,Luque, Rafael
, p. 261 - 266 (2013)
A highly active Fe containing MIL-101 material has been prepared by using a simple microwave-assisted deposition methodology. The material, characterized by several techniques including N2 physisorption, XPS and TEM, was found to have a significantly enhanced acidity due to the incorporation of ca. 2 wt.% Fe in the form of hematite Fe2O3 phase. Fe/MIL-101 exhibited excelling activities in aqueous phase oxidations of alcohols and alkenes using hydrogen peroxide as green oxidant.
New, highly acidic ionic liquid systems and their application in the carbonylation of toluene
Brausch, Nicole,Metlen, Andreas,Wasserscheid, Peter
, p. 1552 - 1553 (2004)
Based on the surprisingly high solubility of AlCl3 in ionic liquids of type [cation][(CF3SO2)2N], a new class of highly acidic, ionic systems has been developed. First tests in toluene carbonylation revealed high potential of these new acidic ionic liquids as catalyst for arene functionaliziation reactions.
Using Data Science To Guide Aryl Bromide Substrate Scope Analysis in a Ni/Photoredox-Catalyzed Cross-Coupling with Acetals as Alcohol-Derived Radical Sources
Doyle, Abigail G.,Gandhi, Shivaani S.,Jiang, Shutian,Kariofillis, Stavros K.,Martinez Alvarado, Jesus I.,?urański, Andrzej M.
supporting information, p. 1045 - 1055 (2022/01/19)
Ni/photoredox catalysis has emerged as a powerful platform for C(sp2)–C(sp3) bond formation. While many of these methods typically employ aryl bromides as the C(sp2) coupling partner, a variety of aliphatic radical sources have been investigated. In principle, these reactions enable access to the same product scaffolds, but it can be hard to discern which method to employ because nonstandardized sets of aryl bromides are used in scope evaluation. Herein, we report a Ni/photoredox-catalyzed (deutero)methylation and alkylation of aryl halides where benzaldehyde di(alkyl) acetals serve as alcohol-derived radical sources. Reaction development, mechanistic studies, and late-stage derivatization of a biologically relevant aryl chloride, fenofibrate, are presented. Then, we describe the integration of data science techniques, including DFT featurization, dimensionality reduction, and hierarchical clustering, to delineate a diverse and succinct collection of aryl bromides that is representative of the chemical space of the substrate class. By superimposing scope examples from published Ni/photoredox methods on this same chemical space, we identify areas of sparse coverage and high versus low average yields, enabling comparisons between prior art and this new method. Additionally, we demonstrate that the systematically selected scope of aryl bromides can be used to quantify population-wide reactivity trends and reveal sources of possible functional group incompatibility with supervised machine learning.
One-step solvent-free aerobic oxidation of aliphatic alcohols to esters using a tandem Sc-Ru?MOF catalyst
Feng, Tingkai,Li, Conger,Li, Tao,Zhang, Songwei
supporting information, p. 1474 - 1480 (2022/03/08)
Esters are an important class of chemicals in industry. Traditionally, ester production is a multi-step process involving the use of corrosive acids or acid derivatives (e.g. acid chloride, anhydride, etc.). Therefore, the development of a green synthetic protocol is highly desirable. This work reports the development of a metal-organic framework (MOF) supported tandem catalyst that can achieve direct alcohol to ester conversion (DAEC) using oxygen as the sole oxidizing agent under strictly solvent-free conditions. By incorporating Ru nanoparticles (NPs) along with a homogeneous Lewis acid catalyst, scandium triflate, into the nanocavities of a Zr MOF, MOF-808, the compound catalyst, Sc-Ru?MOF-808, can achieve aliphatic alcohol conversion up to 92% with ester selectivity up to 91%. A mechanistic study reveals a unique “via acetal” pathway in which the alcohol is first oxidized on Ru NPs and rapidly converted to an acetal on Sc(iii) sites. Then, the acetal slowly decomposes to release an aldehyde in a controlled manner for subsequent oxidation and esterification to the ester product. To the best of our knowledge, this is the first example of DAEC of aliphatic alcohols under solvent-free conditions with high conversion and ester selectivity.
The: In situ fabrication of ZIF-67 on titania-coated magnetic nanoparticles: A new platform for the immobilization of Pd(ii) with enhanced catalytic activity for organic transformations
Kaur, Manpreet,Paul, Satya,Sharma, Chandan,Sharma, Sukanya
, p. 20309 - 20322 (2021/11/22)
Considering the outstanding characteristics of metal organic frameworks (MOFs) and magnetic nanoparticles, herein we report a facile approach for the synthesis of a magnetic zeolitic-imidazolate-framework-supported palladium(ii) catalyst. In brief, zeolitic imidazolate framework-67 (ZIF-67) was successfully incorporated onto the surface of titania-coated magnetic nanoparticles using ethane-1,2-diamine as a linker, and then Pd(ii) was immobilized onto this. The resulting Pd@ZIF-67-Fe3O4-TiO2 catalyst possesses a high surface area (205 m2 g-1), a large pore volume (0.10 cm3 g-1), good magnetic responsivity (10.71 emu g-1), and high stability. A comparative analysis of Pd@ZIF-67-Fe3O4-TiO2 and Pd@Fe3O4-TiO2 catalysts for the oxidation, reduction, and oxidative deprotection of oximes was done to investigate the effects of ZIF-67 on the catalytic performance of Pd species. Substantial differences in activity and stability were observed in the presence of ZIF-67, suggesting that ZIF-67 plays an important role in enhancing the activity of Pd(ii). This superior catalytic activity and stability arises due to a synergistic effect between well-dispersed palladium species and highly porous ZIF-67, which was confirmed via XPS analysis. Moreover, the catalyst retains its structure, chemical environment, and good magnetic response even after five catalytic runs, as confirmed via FTIR, XRD, XPS, and VSM studies of reused catalyst samples.
