31684-93-2Relevant academic research and scientific papers
Synthesis, structural characterization and catalytic properties of a novel monomeric rhenium(V)methyl(oxo)bis(η2-picolinato) complex: [CH3Re(O)(pic)2]
Deloffre, Alexis,Halut, Sabine,Salles, Laurent,Bregeault, Jean-Marie,Gregorio, Jose Ribeiro,Denise, Bernard,Rudler, Henri
, p. 2897 - 2898 (1999)
A methyl mono-oxo rhenium(V) complex with two picolinato chelating ligands has been synthesized and structurally characterized. When reacted with excess 10 or 30% H2O2 it forms peroxo species responsible for the catalytic activity of a highly selective two-phase medium.
Mn(III)-Porphyrin Immobilized on the Graphene Oxide-Magnetite Nanocomposite as an Efficient Heterogeneous Catalyst for the Epoxidation of Alkenes
Bahrami, Elnaz,Hajian, Robabeh
, (2021/10/19)
In this research, β-tetra-brominated meso-tetraphenylporphyrinatomanganese(III) acetate [MnTPPBr4(OAc)] (MnPor) was anchored onto a magnetite imidazole-modified graphene oxide nanosheet (Fe3O4.GO.Im). The obtained catalyst (Fe3O4.GO.Im@MnPor) was characterized through Fourier transform infrared (FT-IR) and diffuse reflectance UV–Visible spectrophotometry (DR UV–Vis), powder X-ray diffractometry (XRD), field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX) spectroscopy, thermogravimetric analysis (TGA) and atomic absorption spectroscopy. The characterization was performed to determine the amount of manganese porphyrin loaded on the GO support. The new immobilized catalyst was employed for the efficient epoxidation of different alkenes with urea hydrogen peroxide (UHP) and acetic acid (HOAc) as oxidant activators under mild conditions. Olefins were oxidized efficiently to their corresponding epoxide with 63–100% selectivity in the presence of Fe3O4.GO.Im@MnPor. Moreover, an remarkable turnover frequency (93) was achieved for the oxidation of α-pinene. The graphene oxide-bound Mn-porphyrin was recovered from the reaction mixture by magnetic decantation and reused several times. Graphic Abstract: [Figure not available: see fulltext.]
Liquid-phase oxidation of olefins with rare hydronium ion salt of dinuclear dioxido-vanadium(V) complexes and comparative catalytic studies with analogous copper complexes
Maurya, Abhishek,Haldar, Chanchal
, (2021/02/26)
Homogeneous liquid-phase oxidation of a number of aromatic and aliphatic olefins was examined using dinuclear anionic vanadium dioxido complexes [(VO2)2(salLH)]? (1) and [(VO2)2(NsalLH)]? (2) and dinuclear copper complexes [(CuCl)2(salLH)]? (3) and [(CuCl)2(NsalLH)]? (4) (reaction of carbohydrazide with salicylaldehyde and 4-diethylamino salicylaldehyde afforded Schiff-base ligands [salLH4] and [NsalLH4], respectively). Anionic vanadium and copper complexes 1, 2, 3, and 4 were isolated in the form of their hydronium ion salt, which is rare. The molecular structure of the hydronium ion salt of anionic dinuclear vanadium dioxido complex [(VO2)2(salLH)]? (1) was established through single-crystal X-ray analysis. The chemical and structural properties were studied using Fourier transform infrared (FT-IR), ultraviolet–visible (UV–Vis), 1H and 13C nuclear magnetic resonance (NMR), electrospray ionization mass spectrometry (ESI-MS), electron paramagnetic resonance (EPR) spectroscopy, and thermogravimetric analysis (TGA). In the presence of hydrogen peroxide, both dinuclear vanadium dioxido complexes were applied for the oxidation of a series of aromatic and aliphatic alkenes. High catalytic activity and efficiency were achieved using catalysts 1 and 2 in the oxidation of olefins. Alkenes with electron-donating groups make the oxidation processes easy. Thus, in general, aromatic olefins show better substrate conversion in comparison to the aliphatic olefins. Under optimized reaction conditions, both copper catalysts 3 and 4 fail to compete with the activity shown by their vanadium counterparts. Irrespective of olefins, metal (vanadium or copper) complexes of the ligand [salLH4] (I) show better substrate conversion(%) compared with the metal complexes of the ligand [NsalLH4] (II).
Kinetic investigation of aerobic epoxidation of limonene over cobalt substituted mesoporous SBA-16
Madadi, Sara,Bergeron, Jean-Yves,Kaliaguine, Serge
, p. 594 - 611 (2021/02/09)
Incorporation of low coordination Co2+within the structure of mesoporous silica SBA-16 has been accomplished through a facile and green “pH adjusting” method. The resulting materials were used as heterogeneous catalysts for aerobic Mukaiyama epoxidation of limonene in the presence of isobutyraldehyde, under very mild conditions. The structural integrity during the pH adjustment procedure at various loadings and states of cobalt ions within the mesoporous structure were determined using characterization techniques including nitrogen physisorption, X-ray fluorescence, diffuse reflectance UV-vis, scanning electron microscopy, temperature-programmed reduction, X-ray photoelectron spectroscopy and powder X-ray diffraction. These catalysts showed quite high reactivity for the epoxidation of limonene with high epoxide yields under optimized oxygen pressure. In this work, a thorough kinetic analysis of aerobic epoxidation of limonene was investigated to allow proposing a reaction scheme. A new mechanism, in which a surface reaction between a Co3+OO?peroxo intermediate and limonene was found to be involved in the formation of the epoxidized limonene. The kinetics developed from the proposed mechanism was accurately fitted with extensive experimental initial reaction rate data. The activation energy for limonene mono epoxide formation was determined to be 22 kJ mol?1
Modification of MnFe2O4 surface by Mo (VI) pyridylimine complex as an efficient nanocatalyst for (ep)oxidation of alkenes and sulfides
Bouzari, Narges,Bezaatpour, Abolfazl,Babaei, Behnam,Amiri, Mandana,Boukherroub, Rabah,Szunerits, Sabine
, (2021/03/04)
In this current paper, we report a new type of heterogeneous molybdenum (+6) complex, prepared by covalent grafting of cis-dioxo?molybdenum (VI) pyridylimine complex on the surface of MnFe2O4 nanoparticles (NP) and characterized using various physicochemical techniques. The recyclable prepared nanocatalyst was tested for sulfoxidation of sulfides and epoxidation of alkenes under solvent-free condition. The catalyst exhibited high turnover frequency for the oxidization of cyclooctene and cyclohexene (10,850 h?1) and thioanisole and dimethyl sulfide (41,250 h?1). The synthesized catalyst was found highly efficient, retrievable and eco-friendly catalyst for the (ep)oxidation of alkenes and sulfides in excellent yields in a short time. Furthermore, the synthesized nanocatalyst can be reused for four runs without apparent loss of its catalytic activity in the oxidation reaction.
Homogeneous catalytic oxidation of alkenes employing mononuclear vanadium complex with hydrogen peroxide
Maurya, Abhishek
, p. 3261 - 3269 (2020/07/14)
Abstract: Homogeneous liquid-phase oxidation of alkenes (allylbenzene, cis-cyclooctene, 4-chlorostyrene, styrene, 2-norbornene, 1-methyl cyclohexene, indene, lemonine, and 1-hexene) were catalyzed by using vanadium complex [VO(hyap)(acac)2] in existence of H2O2. The complex [VO(hyap)(acac)2] was formed as a crystal by the reaction of [VO(acac)2] and 2-hydroxyacetophenone (hyap) in the presence of methanol by refluxing the reaction mixture. Various analytical and spectroscopic techniques, namely FTIR, ESI–MS, UV–Vis, single-crystal XRD, and EPR, were used to analyze and optimize the structure of the complexes. Graphic abstract: [Figure not available: see fulltext.].
Selective Catalytic Synthesis of 1,2- and 8,9-Cyclic Limonene Carbonates as Versatile Building Blocks for Novel Hydroxyurethanes
Maltby, Katarzyna A.,Hutchby, Marc,Plucinski, Pawel,Davidson, Matthew G.,Hintermair, Ulrich
supporting information, p. 7405 - 7415 (2020/05/25)
The selective catalytic synthesis of limonene-derived monofunctional cyclic carbonates and their subsequent functionalisation via thiol–ene addition and amine ring-opening is reported. A phosphotungstate polyoxometalate catalyst used for limonene epoxidation in the 1,2-position is shown to also be active in cyclic carbonate synthesis, allowing a two-step, one-pot synthesis without intermittent epoxide isolation. When used in conjunction with a classical halide catalyst, the polyoxometalate increased the rate of carbonation in a synergistic double-activation of both substrates. The cis isomer is shown to be responsible for incomplete conversion and by-product formation in commercial mixtures of 1,2-limomene oxide. Carbonation of 8,9-limonene epoxide furnished the 8,9-limonene carbonate for the first time. Both cyclic carbonates underwent thiol–ene addition reactions to yield linked di-monocarbonates, which can be used in linear non-isocyanate polyurethanes synthesis, as shown by their facile ring-opening with N-hexylamine. Thus, the selective catalytic route to monofunctional limonene carbonates gives straightforward access to monomers for novel bio-based polymers.
Synthesis of dipyroromethanes in water and investigation of electronic and steric effects in efficiency of olefin epoxidation by sodium periodate catalyzed by manganese tetraaryl and trans disubstituted porphyrin complexes
Bagherzadeh, Mojtaba,Jonaghani, Mohammad Adineh,Amini, Mojtaba,Mortazavi-Manesh, Anahita
, p. 671 - 678 (2019/04/26)
Condensation of pyrrole with various aldehydes in the presence of BF3?etherate as an acid catalyst in water provides good yield of some dipyrromethanes. Prolongation of the reaction time with aldehydes substituted by electron-donating (mesityl) or electron-withdrawing (2,6-dichlorophenyl) groups on the ortho positions of the phenyl did not lead to decomposition or scrambling. Manganese trans disubstituted porphyrin complexes which derive from various dipyrromethanes and manganese tetraaryl porphyrin complexes including various substituents with different steric and electronic properties show good catalytic activity in epoxidation of alkenes by NaIO4 in the presence of imidazole (ImH). The study of steric and electronic effects of the catalysts on the epoxidation of olefins shows that Mn-porphyrin complexes with more bulky and electron-releasing groups on meso phenyls could increase the epoxidation yield of most alkenes.
High surface area, nanostructured boehmite and alumina catalysts: Synthesis and application in the sustainable epoxidation of alkenes
Lueangchaichaweng, Warunee,Singh, Bhawan,Mandelli, Dalmo,Carvalho, Wagner A.,Fiorilli, Sonia,Pescarmona, Paolo P.
, p. 180 - 187 (2019/01/04)
We report a new, straightforward and inexpensive sol-gel route to prepare boehmite nanorods [γ-AlO(OH)-NR] with an average length of 23 nm ± 3 nm, an average diameter of 2 nm ± 0.3 nm and a high specific surface area of 448 m2/g, as evidenced by TEM and N2-physisorption, respectively. The boehmite was converted to γ-alumina with preserved nanorod morphology (γ-Al2O3-NR) and high surface area upon calcination either at 400 or 600 °C. These nanostructured materials are active and selective heterogeneous catalysts for the epoxidation of alkenes with the environmentally friendly H2O2. The best catalyst, γ-Al2O3-NR-400, showed to be versatile in the scope of alkenes that could be converted selectively to their epoxide and displayed enhanced reusability compared to previously reported alumina catalysts. Furthermore, the catalytic performance of the material was enhanced by optimising the reaction conditions such as the solvent and the type of hydrogen peroxide source. Under the optimised reaction conditions, the γ-Al2O3-NR-400 catalyst displayed 58% cyclooctene oxide yield after 4 h of reaction at 80 °C with full selectivity towards the epoxide product. The correlation between the catalytic activity of these materials and their physicochemical properties such as surface area, hydrophilicity and number and type of acid sites was critically discussed based on a detailed characterisation study.
Epoxidation of limonene over low coordination Ti in Ti- SBA-16
Charbonneau, Luc,Kaliaguine, Serge
, p. 1 - 8 (2017/01/16)
Epoxidation of limonene was studied over Ti-SBA-16 catalysts prepared using two different post grafting techniques. The first one consisted of an in-situ synthesis of a titanium acetylacetone (ACAC) precursor and the other one used directly TiO(ACAC)2. Reaction conditions such as temperature, concentration of TBHP and solvent polarity were examined. The reaction should be carried out at 75?°C in acetonitrile using a TBHP/limonene molar ratio of 11/6. The conversion of limonene reached 80% with a 1,2-limonene oxide selectivity of 79% for both impregnation methods using Ti-SBA-16 with a Ti/Si atomic ratio of 7.3%. Under the same conditions the 3D pore structure of SBA-16 support favors reactants and products mass transfer compared to the 2D pore structure of SBA-15. No differences in catalytic activity were observed as atomic ratio Ti/Si was varied from 5 to 13.4% in Ti-SBA-16. Repeated catalytic tests showed no change in activity over three process cycles.
