1686-14-2Relevant articles and documents
Growth of Cu-BTC MOFs on dendrimer-like porous silica nanospheres for the catalytic aerobic epoxidation of olefins
Zhou, Zihao,Li, Xiujuan,Wang, Yulin,Luan, Yi,Li, Xiaoyu,Du, Xin
, p. 14350 - 14357 (2020)
The composition of metal-organic frameworks (MOFs) and porous carriers can be utilized for a variety of material applications. In this study, DPSNs@Cu-BTC nanocomposites are achieved utilizing Dendrimer-like Porous Silica Nanoparticles (DPSNs) as the support through a template-mediated self-assembly mechanism. The fabrication process is initiated from the controllable growth of Cu2O nanoparticles (NPs) in the center-radial porous channels of DPSNs, which forms DPSNs@Cu2O nanocomposites. Under the protection of DPSNs, the loaded Cu2O NPs gradually dissolved in the weak acid solution, thus providing copper ions to guide the formation and growth of Cu-BTC nanocrystals. Moreover, the Cu-BTC NPs were restricted in the center-radial porous channels of the DPSNs, thus resulting in small sizes and a uniform distribution. The formation of the DPSNs@Cu-BTC nanocomposites with adjustable amounts of Cu-BTC mainly depended on the amounts of Cu2O NPs loaded and the amount of organic ligands added. Furthermore, the nanocomposite exhibited high catalytic performance and good recyclability taking advantage of the uniform loading of small-sized Cu-BTC NPs in the accessible center-radial porous channels of the DPSNs. This new design of DPSNs@Cu-BTC provided a new approach for the synthesis of various MOF-based nanocomposites with improved performance.
Molecular structure-activity relationships for the oxidation of organic compounds using mesoporous silica catalysts derivatised with bis(halogeno)dioxomolybdenum(VI) complexes
Nunes, Carla D.,Valente, Anabela A.,Pillinger, Martyn,Rocha, Joao,Goncalves, Isabel S.
, p. 4380 - 4390 (2003)
Mo K-edge XAFS spectra have been measured for ordered mesoporous silica MCM-41 grafted with the complexes [MoO2X2(thf) 2] (X = Cl, Br). For grafting reactions in the absence of triethylamine, materials with 1 wt.% Mo are obtained; the Mo K-edge EXAFS results indicate the co-existence of isolated surface-fixed monomeric species {MoO2[(-O)3SiO]2(thf)n} and {MoO2[(-O)3SiO]X(thf)n}. When Et3N is used in the grafting reactions, materials with 4 wt. % Mo are obtained. The EXAFS data for the material prepared using [MoO2Cl 2(thf)2] and Et3N indicate the presence of dinuclear species with two MoVI centres, each with two Mo=O groups and each linked by one or two oxo bridges (Mo...Mo 3.27 A). The molybdenum centres in the material prepared using the dibromo complex comprise mainly isolated four-coordinate dioxomolybdenum(VI) and trioxomolybdenum(VI) monomeric species, with a small contribution from dimeric acterised in the solid state by powder X-ray diffraction, N2 adsorption analysis, MAS NMR (13C, 29Si) and FTIR spectroscopy. The derivatised MCMs perform differently as catalysts in the liquid-phase oxidation of various olefins and alcohols with tert-butyl hydroperoxide. The highest alkene epoxidation activity was recorded for the catalysts with low metal loading, whereas the material containing oxo-bridged dimers had the highest activity for oxidation of alcohols. The recyclability of all the catalysts was tested: the catalytic activity of the derivatised materials tended to stabilize with ageing.
Synthesis of a reusable polymer anchored cobalt(II) complex for the aerobic oxidation of alkyl aromatics and unsaturated organic compounds
Islam, Sk Manirul,Ghosh, Kajari,Molla, Rostam Ali,Roy, Anupam Singha,Salam, Noor,Iqubal, Md Asif
, p. 61 - 69 (2014)
Polymer anchored cobalt(II) catalyst was synthesized and characterized. The solid catalyst was characterized by fourier transform infrared spectroscopy (FT-IR), UV-vis diffuse reflectance spectroscopy (DRS), thermogravimetric analysis (TGA) and scanning electron microscope (SEM). The catalytic activity of the complex was investigated for the oxidative functionalization of alkyl aromatics to benzylic ketones using O2 (1 atm) with 1 mmol H2O2. The oxidation of organic compounds with carbon-carbon double bond with molecular oxygen under atmospheric pressure in the presence of this catalyst has also been studied. Oxidation of alkenes, cycloalkenes and terpenes gave corresponding epoxy derivatives. The developed catalyst can be facilely recovered and reused six times without significant decrease in its activity and selectivity.
Epoxidation of olefins by molecular oxygen using perfluorocarbons as reaction media
Pozzi, Gianluca,Montanari, Fernando,Rispens, Minze T.
, p. 447 - 452 (1997)
Epoxidation of olefins by dioxygen in combination with aldehyde as reducing agent can be carried out at room temperature, in the absence of metal catalysts, using perfluorocarbons as inert reaction media. These non-toxic, non ozone-depleting fluids are good alternatives to the chlorinated solvents normally used.
Hierarchical PS/PANI nanostructure supported Cu(ii) complexes: Facile synthesis and study of catalytic applications in aerobic oxidation
Yu, Jie,Luan, Yi,Qi, Yue,Hou, Junying,Dong, Wenjun,Yang, Mu,Wang, Ge
, p. 55028 - 55035 (2014)
Hierarchical heterogeneous copper catalysts were prepared by immobilization of a homogeneous copper(ii) complex on the surface of polystyrene/polyaniline (PS/PANI) microspheres with oriented PANI nanofibers. EDX element maps and XPS spectra indicated that Cu2+ ions strongly coordinated with PANI imine. PS/PANI@Cu(OSO2CF3)2 exhibited excellent catalytic activity for selective aerobic oxidation of alcohols and highly efficient aerobic epoxidation of alkenes under mild conditions. The supported copper(ii) catalyst maintained high levels of conversion and selectivity in these reactions after six cycles and showed good stability. This journal is
Synthesis, characterization, and application of a new nanohybrid Schiff base polyoxometalate in epoxidation of olefins in the presence of tert-butyl hydroperoxide
Hosseinyzade, Samira S.,Zonoz, Farrokhzad M.,Bahramian, Bahram
, p. 243 - 254 (2020)
The new molybdenyl acetylacetonate Schiff base complex with mono-lacunary polyoxometalate (1) was synthesized in the reaction of [PMo11O39]7-, molybdenum acetylacetonate (MoO2(acac)2), and ethylenediamine. The catalyst was characterized by elemental analysis and various routine techniques like FT-IR, XRD, FESEM, EDX, UV–Vis, and TGA. The catalytic activities of this nanocatalyst were examined for epoxidation of linear, cyclic and phenyl-substituted olefins using tert-butyl hydroperoxide (tert-BuOOH) as oxidant.
Dry gel conversion method for the synthesis of organic-inorganic hybrid MOR zeolites with modifiable catalytic activities
Zhou, Dan,Lu, Xinhuan,Xu, Jun,Yu, Anan,Li, Jiyang,Deng, Feng,Xia, Qinghua
, p. 4160 - 4165 (2012)
Dry gel conversion (DGC) technique is first applied in the synthesis of organic-inorganic hybrid aluminosilicate zeolites. By using the DGC method, methylene-bridged organic-inorganic hybrid zeolites with an MOR topology are synthesized without organic additive, which are structurally characterized by powder XRD, FTIR, solid-state 29Si, 13C, 27Al MAS NMR, SEM, elemental analysis, XRF, XPS, and N2 adsorption techniques. This work first reports that thus-synthesized methylene-bridged hybrid zeolites can be successfully bestowed with excellent catalytic activities through different modification treatments. Co2+-exchanged hybrid zeolites are applied in the epoxidation of alkenes with air to achieve good conversions and selectivities. Especially, methylene-bridged hybrid zeolites can be sulfonated with fuming sulfuric acid to form acidic MOR-SO3H catalyst, which exhibits highly catalytic activity for the acid-catalyzed condensation reaction of cyclohexanone and glycol. This method will be one potential route for the fabrication of organic-inorganic hybrid zeolite or related molecular sieve catalysts.
Development of the catalytic reactiVIty of an oxo-peroxo Mo(VI) Schiff base complex supported on supermagnetic nanoparticles as a reusable green nanocatalyst for selective epoxidation of olefins
Bezaatpour, Abolfazl,Khatami, Sahar,Amiri, Mandana
, p. 27452 - 27459 (2016)
A novel ancillary branch coated oxo-peroxo Mo(vi)tetradentate Schiff base complex on superparamagnetic nanoparticles was prepared and characterized by IR spectroscopy, X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), vibrating sample magnetometry (VSM), diffuse reflectance spectra (DRS) and atomic absorption spectroscopy (AAS). The catalyst was used for the selective epoxidation of cyclooctene, cyclohexene, styrene, indene, α-pinene, 1-hepten, 1-octene, 1-dodecen and trans-stilben using tert-butyl hydroperoxide as an oxidant in 1,2-dichloroethane. This catalyst is efficient for the oxidation of cyclooctene, with a moderate 100% selectivity for epoxidation with 97% conversion in 30 min. We were able to separate the supermagnetic nanocatalyst by using an external magnetic field, and to use the catalyst at least five successive times without significant decrease in conversion. The proposed supermagnetic nanocatalyst has advantages in catalytic activity, selectivity, catalytic reaction time and reusability by easy separation.
Fast-synthesis and catalytic property of heterogeneous Co-MOF catalysts for the epoxidation of α-pinene with air
Zhang, Haifu,He, Jie,Lu, Xinhuan,Yang, Lu,Wang, Chenlong,Yue, Fanfan,Zhou, Dan,Xia, Qinghua
, p. 17413 - 17421 (2020)
In the past decades, many methods have been developed for synthesizing MOFs, including solvothermal synthesis, mechanical synthesis, electrochemical synthesis, and microwave synthesis. Based on the existing research, a method is proposed for synthesizing Co-MOF by rapidly rotating hydrothermal crystallization, which largely shortens the crystallization time of Co-MOF. When the rotation speed was 150 rpm, only 2 h of crystallization time was needed to synthesize Co-MOF-150-2 with high crystallinity and stability. The optimal Co-MOF-150-2 manifested remarkable activity and selectivity for the epoxidation of α-pinene under mild conditions. The catalytic conversion of α-pinene reached the highest over the Co-MOF-150-2 catalyst, in which the conversion of α-pinene was 99.5% and the yield of 2,3-epoxypinane was 95.7%. The Co-MOF materials synthesized by the rotary method also had excellent stability and highly catalytic activity in recycling experiments. This journal is
Aerobic oxidation of Α-pinene catalyzed by homogeneous and MOF-based Mn catalysts
Raupp, Yasmin S.,Yildiz, Ceylan,Kleist, Wolfgang,Meier, Michael A.R.
, p. 1 - 6 (2017)
Manganese catalysts were investigated for the liquid-phase aerobic oxidation of α‐pinene. First, the influence of reaction parameters such as time, solvent, temperature, oxidant flow rate and catalyst concentration on conversion, yield and selectivity were evaluated using Mn(III) acetate as homogeneous catalyst. Mn(III) acetate afforded pinene oxide as the main product along with small amounts of verbenol and verbenone. The optimized reaction conditions were likewise applied to a novel mixed-linker metal-organic framework (MOF) based on MIL-53-NH2(Al), which was successfully synthesized and modified in a two-step post-synthetic reaction using maleic anhydride and Mn(III) acetate. The performance of the Mn-containing MOF catalyst was directly compared to its homogeneous counterpart Mn(III) acetate, showing very similar activity in a mixture of diethyl carbonate/dimethylformamide (DEC/DMF) as solvent. In both cases, a conversion of 31% and the formation of 17% pinene oxide (55% selectivity) were observed after 6 h. The heterogeneous MOF catalyst was easily removed from the reaction mixture by filtration and reused for at least five catalytic cycles without significant loss of activity. A hot filtration test showed that the catalysis mainly proceeded heterogeneously, although minor contributions of homogeneous species could not be completely excluded.
Synthesis and catalytic properties of titanium containing extra-large pore zeolite CIT-5
P?ech, Jan,Kub?, Martin,?ejka, Ji?í
, p. 80 - 86 (2014)
Titanium containing extra-large pore zeolite CIT-5 (IZA code: CFI) was successfully prepared by direct synthesis using Cab-O-Sil M5 and titanium(IV) butoxide in the presence of LiOH. N-Methylsparteinium hydroxide was used as a structure directing agent. The product crystallized into thin plate crystals with an approximate size of 20 × 5 × 0.2 μm. The lowest achieved Si/Ti ratio was 23. The necessary duration of hydrothermal synthesis increased with increasing concentration of Ti in the reaction mixture from 11 days (Si/Ti = 63 in product) to 17 days (Si/Ti = 36) at 155 C. Prepared Ti-CFI samples exhibit BET surface areas in the range of 308-346 m2/g and micropore volumes of 0.094-0.097 cm3/g. CFI possesses extra-large pores (14-ring, 7.2 × 7.5 A?) accessible for bulky molecules, therefore, Ti-CFI is a useful catalyst for epoxidation of double bonds in bulky molecules used in perfumery and pharmacy. The Ti-CFI samples proved to be catalytically active in epoxidation of 1-octene, cyclooctene, α-pinene, and norbornene with hydrogen peroxide as oxidation agent.
Synthesis, characterization, crystal structure determination and catalytic activity in epoxidation reaction of two new oxidovanadium(IV) Schiff base complexes
Tahmasebi, Vida,Grivani, Gholamhossein,Bruno, Giuseppe
, p. 367 - 374 (2016)
The five coordinated vanadium(IV) Schiff base complexes of VOL1 (1) and VOL2 (2), HL1?=?2-{(E)-[2-bromoethyl)imino]methyl}-2- naphthol, HL2?=?2-{(E)-[2-chloroethyl)imino]methyl}-2- naphthol, have been synthesized and they were characterized by using single-crystal X-ray crystallography, elemental analysis (CHN) and FT-IR spectroscopy. Crystal structure determination of these complexes shows that the Schiff base ligands (L1 and L2) act as bidentate ligands with two phenolato oxygen atoms and two imine nitrogen atoms in the trans geometry. The coordination geometry around the vanadium(IV) is distorted square pyramidal in which vanadium(IV) is coordinated by two nitrogen and two oxygen atoms of two independent ligands in the basal plane and by one oxygen atom in the apical position. The catalytic activity of the Schiff base complexes of 1 and 2 in the epoxidation of alkenes were investigated using different reaction parameters such as solvent effect, oxidant, alkene/oxidant ratio and the catalyst amount. The results showed that in the presence of TBHP as oxidant in 1: 4 and 1:3 ratio of the cyclooctene/oxidant ratio, high epoxide yield was obtained for 1 (76%) and 2 (80%) with TON(= mole of substrate/mole of catalyst) of 27 and 28.5, respectively, in epoxidation of cyclooctene.
A convenient 3-step synthesis of (R)-7-hydroxycarvone from (S)-α-pinene
Lakshmi, Rajamma,Bateman, T. David,McIntosh, Matthias C.
, p. 5313 - 5315 (2005)
A convenient 3-step synthesis of (R)-7-hydroxycarvone (2) has been developed starting from (S)-α-pinene (7), using photooxygenation, oxidation, and fragmentation reactions. An improved synthesis of epoxy alcohol 6 and an unusual Ti(OiPr)4 catalyzed hydroxy epoxide to keto alcohol rearrangement are also described.
A recyclable cobalt(iii)-ammonia complex catalyst for catalytic epoxidation of olefins with air as the oxidant
Wang, Chenlong,Zhan, Hongju,Lu, Xinhuan,Jing, Run,Zhang, Haifu,Yang, Lu,Li, Xixi,Yue, Fanfan,Zhou, Dan,Xia, Qinghua
supporting information, p. 2147 - 2156 (2021/02/06)
[Co(NH3)6]Cl3and other ammonia complexes with different external anions or metal ions were synthesized to catalyze the epoxidation of α-pinene. The synthesized complexes were characterized using XRD, SEM, TGA, FTIR and UV spectra. With air as the oxidant, [Co(NH3)6]Cl3exhibited excellent catalytic activity for the epoxidation of α-pinene among the prepared complexes. The conversion of α-pinene reached 97.4%, with 98.3% selectivity of epoxide when using a small amount of cumene hydroperoxide (CHP) as the initiator. The results revealed that a single Co(iii) system can also catalyze the epoxidation process in the absence of Co(ii), even showing better catalytic performance than single Co(ii). Recycling experiments showed that there was no significant drop in activity after 10 cycles, demonstrating that it is a stable and efficient heterogeneous catalyst for the epoxidation of α-pinene. The excellent recycling performance may be attributed to the stability of the coordination complex itself.
Sustainable catalytic epoxidation of biorenewable terpene feedstocks using H2O2as an oxidant in flow microreactors
Bull, Steven D.,Cunningham, William B.,Plucinski, Pawel,Tibbetts, Joshua D.,Vezzoli, Massimiliano
supporting information, p. 5449 - 5455 (2021/08/16)
Solvent-free continuous flow epoxidation of the alkene bonds of a range of biorenewable terpene substrates have been carried out using a recyclable tungsten-based polyoxometalate phase transfer catalyst and aqueous H2O2 as a benign oxidant. These sustainable flow epoxidation reactions are carried out in commercial microreactors containing static mixing channels that enable common monoterpenes (e.g. untreated crude sulfate turpentine, limonene, etc.) to be safely epoxidized in short reaction times and in good yields. These flow procedures are applicable for the flow epoxidation of trisubstituted and disubstituted alkenes for the safe production of multigram quantities of a wide range of epoxides. This journal is
