99-94-5Relevant articles and documents
Synthesis, O2-binding ability and catalytic oxidation performance of cobalt(II) complexes with dihydroxamic acid functionalized N-pivot lariat ethers
Wei, Xing-Yue,Wang, Xing-Min,Li, Ning,Qin, Sheng-Ying
, p. 100 - 102 (2015)
Novel Co(II) complexes with dihydroxamic acids functionalized N-pivot lariat ether CoL1-CoL4 were synthesized and characterized. Their oxygenation constants (ln KO2) and thermodynamic parameters (ΔH°, ΔS°) were measured. And their catalytic performance in oxidation of p-xylene to p-toluic acid (PTA) was investigated. The enhancement of O2-binding and catalytic oxidation activity by the oxa aza crown ether ring of the cobalt complexes were discussed.
Correlation of Intermolecular Acyl Transfer Reactivity with Noncovalent Lattice Interactions in Molecular Crystals: Toward Prediction of Reactivity of Organic Molecules in the Solid State
Krishnaswamy, Shobhana,Shashidhar, Mysore S.
, p. 3952 - 3959 (2018)
Intermolecular acyl transfer reactivity in several molecular crystals was studied, and the outcome of the reactivity was analyzed in the light of structural information obtained from the crystals of the reactants. Minor changes in the molecular structure resulted in significant variations in the noncovalent interactions and packing of molecules in the crystal lattice, which drastically affected the facility of the intermolecular acyl transfer reactivity in these crystals. Analysis of the reactivity vs crystal structure data revealed dependence of the reactivity on electrophile···nucleophile interactions and C-H···π interactions between the reacting molecules. The presence of these noncovalent interactions augmented the acyl transfer reactivity, while their absence hindered the reactivity of the molecules in the crystal. The validity of these correlations allows the prediction of intermolecular acyl transfer reactivity in crystals and co-crystals of unknown reactivity. This crystal structure-reactivity correlation parallels the molecular structure-reactivity correlation in solution-state reactions, widely accepted as organic functional group transformations, and sets the stage for the development of a similar approach for reactions in the solid state.
An efficient aerobic oxidation for p-xylene to p-toluic acid by unsymmetrical Schiff base manganese(III) complexes with pendant benzo-10-aza-crown ether or morpholino-groups
Li, Jian-Zhang,Yang, Zhu-Zhu,He, Xi-Yang,Zeng, Jun,Qin, Sheng-Ying
, p. 581 - 584 (2010)
Unsymmetrical Schiff base Mn(III) complexes with pendant aza-crown or morpholino groups have been synthesised and studied as catalysts in aerobic oxidation of ρ-xylene to ρ-toluic acid (PTA). The oxidation of ρ-xylene to ρ-toluic acid with air at 120 °C under normal atmospheric pressure occurred efficiently in the presence of aza-crown ether substituted unsymmetrical Schiff base Mn(III) complexes. Significant selectivity (up to ～90%) and conversion levels (up to ～40%) were obtained. The effect of the pendant aza-crown ether group in Mn(III) Schiff base complexes on the oxidation of ρ-xylene was also investigated by comparison with the pendant morpholino-group analogues. The addition of Na+ cation accelerated the rate of conversion of ρ-xylene to ρ-toluic acid.
Ordered mesoporous V2O5/WO3 composite catalysts for efficient oxidation of aryl alcohols
Skliri, Euaggelia,Lykakis, Ioannis N.,Armatas, Gerasimos S.
, p. 46170 - 46178 (2014)
Multicomponent mesoporous metal oxides show promise in the area of heterogeneous catalysis due to the synergetic interactions between the framework components and the high internal surface area. In this study, we present the synthesis of ordered mesoporous tungsten(vi) oxide-vanadium oxide (V2O5) nanocomposite frameworks via a two-step wet chemical deposition and nanocasting process and demonstrate that they exhibit high catalytic activity and stability for the oxidation of aryl alcohols, using tert-butyl hydroperoxide (t-BuOOH) as oxidant. X-ray diffraction, transmission electron microscopy and nitrogen porosimetry results indicate that the template-free materials possess a 3D mesoscopic structure of discernible domains of parallel-arranged nanorods and have an internal pore surface with narrow mesopores. The chemical composition and molecular structure of the mesoporous matrix were determined with elemental X-ray microanalysis (EDS), diffuse reflectance ultraviolet-visible (UV-vis) and Raman spectroscopy. Our catalytic results indicate that a small addition of V2O5 into the lattice of WO3 has a beneficial effect on the catalytic performance. Thus, the 4% V2O5-loaded WO3 catalyst shows a large improvement in the oxidation of various para-substituted aryl alcohols with respect to the pure mesoporous WO3, giving good-to-high yields (ca. 80-100%) of the target products within 1-4 h reaction time.
Effects of ligand composition on the oxidative carbonylation of toluene to toluic acid catalyzed by Rh(III) complexes
Zakzeski, Joseph,Behn, Andrew,Head-Gordon, Martin,Bell, Alexis T.
, p. 11098 - 11105 (2009)
Experimental and theoretical studies were conducted to investigate the influence of anionic ligands (e.g., CF3COO-, CH 3SO3-) on the catalytic activity and selectivity of Rh(III) in the oxidative carb
A Sustainable Route to a Terephthalic Acid Precursor
Banella, Maria Barbara,Gioia, Claudio,Vannini, Micaela,Colonna, Martino,Celli, Annamaria,Gandini, Alessandro
, p. 942 - 945 (2016)
A new synthetic pathway for the production of p-toluic acid has been developed starting from reagents derived from renewable resources. A Diels-Alder reaction between sorbic and acrylic acids is followed by a combined dehydrogenation/ decarboxylation process, providing p-toluic acid in high yields. This route permits to use milder conditions compared to other Diels-Alder approaches reported in the literature, and therefore can contribute to a more sustainable terephthalic acid production.
Gram-scale synthesis of carboxylic acids via catalytic acceptorless dehydrogenative coupling of alcohols and hydroxides at an ultralow Ru loading
Chen, Cheng,Cheng, Hua,Verpoort, Francis,Wang, Zhi-Qin,Wu, Zhe,Yuan, Ye,Zheng, Zhong-Hui
, (2021/12/13)
Acceptorless dehydrogenative coupling (ADC) of alcohols and water/hydroxides is an emergent and graceful approach to produce carboxylic acids. Therefore, it is of high demand to develop active and practical catalysts/catalytic systems for this attractive transformation. Herein, we designed and fabricated a series of cyclometallated N-heterocyclic carbene-Ru (NHC-Ru) complexes via ligand tuning of [Ru-1], the superior complex in our previous work. Gratifyingly, gram-scale synthesis of carboxylic acids was efficiently enabled at an ultralow Ru loading (62.5 ppm) in open air. Moreover, effects of distinct ancillary NHC ligands and other parameters on this catalytic process were thoroughly studied, while further systematic studies were carried out to provide rationales for the activity trend of [Ru-1]-[Ru-7]. Finally, determination of quantitative green metrics illustrated that the present work exhibited superiority over representative literature reports. Hopefully, this study could provide valuable input for researchers who are engaging in metal-catalyzed ADC reactions.
Mechanochemical Grignard Reactions with Gaseous CO2 and Sodium Methyl Carbonate**
Pfennig, Victoria S.,Villella, Romina C.,Nikodemus, Julia,Bolm, Carsten
supporting information, (2022/01/22)
A one-pot, three-step protocol for the preparation of Grignard reagents from organobromides in a ball mill and their subsequent reactions with gaseous carbon dioxide (CO2) or sodium methyl carbonate providing aryl and alkyl carboxylic acids in up to 82 % yield is reported. Noteworthy are the short reaction times and the significantly reduced solvent amounts [2.0 equiv. for liquid assisted grinding (LAG) conditions]. Unexpectedly, aryl bromides with methoxy substituents lead to symmetric ketones as major products.
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.
Transformation of Thioacids into Carboxylic Acids via a Visible-Light-Promoted Atomic Substitution Process
Fu, Qiang,Liang, Fu-Shun,Lou, Da-Wei,Pan, Gao-Feng,Wang, Rui,Wu, Min,Xie, Kai-Jun
supporting information, p. 2020 - 2024 (2022/03/31)
A visible-light-promoted atomic substitution reaction for transforming thiocacids into carboxylic acids with dimethyl sulfoxide (DMSO) as the oxygen source has been developed, affording various alkyl and aryl carboxylic acids in over 90% yields. The atomic substitution process proceeds smoothly through the photochemical reactivity of the formed hydrogen-bonding adduct between thioacids and DMSO. A DMSO-involved proton-coupled electron transfer (PCET) and the simultaneous generation of thiyl and hydroxyl radicals are proposed to be key steps for realizing the transformation.
