529-20-4Relevant articles and documents
Chromium trioxide supported onto wet silica gel: Rapid oxidation of alcohols to carbonyl compounds under microwave irradiation in solventless system
Heravi, Majid M.,Farhangi, Nasrin,Beheshtiha, Yahya Sh.,Assadolah, Karim,Ghassemzadeh, Mitra,Tabar-Hydar, Koroush
, p. 2883 - 2885 (2002)
In an environmentally benign system, alcohols are rapidly oxidized to carbonyl compounds using CrO3 supported onto wet silica gel as an oxidant under microwave irradiation.
Selective vapor-phase oxidation of o-xylene to phthalic anhydride over Co-Mn/H3PW12O40@TiO2 using molecular oxygen as a green oxidant
Masoomi, Kianoosh,Ghiaci, Mehran,Botelho do Rego
, (2018)
The oxidation of o-xylene to phthalic anhydride over Co-Mn/H3PW12O40@TiO2 was investigated. The experimental results demonstrated that the prepared catalyst effectively catalyzed the oxidation of o-xylene to phthalic anhydride. Also, the synergistic effect between three metals plays vital roles in this reaction. From a green chemistry point of view, this method is environmentally friendly due to carrying out the oxidation in a fixed-bed reactor under solvent-free condition and using molecular oxygen as a green and cheap oxidizing agent. The resulting solid catalysts were characterized by FT-IR, XRD, XPS, ICP-OES, FESEM, TEM, EDX, DR-UV spectroscopy, BET and thermogravimetric analysis. The oxidation of o-xylene yields four products: o-tolualdehyde, phthaldialdehyde, phthalide and finally phthalic anhydride as the main product. The reaction conditions for oxidation of o-xylene were optimized by varying the temperature, weight hourly space velocity and oxygen flow rate (contact time). The optimum weight percentage of phosphotungstic acid (HPW) and Co/Mn for phthalic anhydride production were 15?wt % and 2?wt%, respectively. The best Co/Mn ratio was found to be 10/1. Oxygen flow rate was very important on the phthalic anhydride formation. The optimum conditions for oxidation of o-xylene were T?=?370?°C, WHSV?=?0.5?h?1 and oxygen flow rate?=?10?mL?min?1. Under optimized conditions, a maximum of 88.2% conversion and 75.5% selectivity to phthalic anhydride was achieved with the fresh catalyst. Moreover, reusability of the catalyst was studied and catalytic activity remained unchanged after at least five cycles.
Synthesis of Oxetans by Photocycloaddition of Aromatic Aldehydes to Hexamethyl(Dewar benzene)
Carless, Howard A. J.,Trivedi, Harish S.
, p. 950 - 951 (1981)
U.v. irradiation of the aldehydes (3) in the presence of hexamethyl(Dewar benzene) yields the tricyclic oxetans (4) and (5) in competition with hexamethylbenzene formation.
Palladium-Catalyzed ortho C?H Arylation of Benzaldehydes Using ortho-Sulfinyl Aniline as Transient Auxiliary
Mu, Delong,He, Gang,Chen, Gong
, p. 2423 - 2426 (2018)
A PdII-catalyzed ortho-(Csp2)–H arylation reaction of benzaldehydes using a catalytic amount of 2-(methylsulfinyl)aniline as transient auxiliary was developed. This reaction is compatible with a broad range of benzaldehyde and aryl iodide substrates. Compared with other related reaction systems, an excellent regioselectivity for ortho-C(sp2)?H bonds over benzylic C(sp3)?H bonds was obtained for ortho-alkyl-benzaldehyde substrates.
A hierarchical Fe3O4@P4VP@MoO2(acac) 2 nanocomposite: Controlled synthesis and green catalytic application
Guo, Wanchun,Wang, Ge,Wang, Qian,Dong, Wenjun,Yang, Mu,Huang, Xiubing,Yu, Jie,Shi, Zhan
, p. 344 - 349 (2013)
Magnetite/poly(4-vinylpyridine) composite nanospheres with multiple Fe 3O4 cores embedded in a P4VP shell were first synthesized by miniemulsion polymerization and then used as recoverable supports for MoO2(acac)2 complex. The supported complex, together with superparamagnetism and strong magnetic response, showed high efficiency for the catalytic epoxidation of cis-cyclooctene with aqueous H2O2 in ethanol. The response strongly facilitated the easy recovery of the catalyst, which was stable in recycling tests.
ULTRASOUND IN ORGANIC SYNTHESIS 10. SELECTIVE ORTHO-LITHIATION OF THE BOUVEAULT REACTION INTERMEDIATE
Einhorn, J.,Luche, J. L.
, p. 1793 - 1796 (1986)
The Bouveault reaction intermadiate prepared under sonochemical conditions easily undergoes orthodirected lithiation.The use of tetrahydropyran as a solvent dramatically increases the rates and yields of metallation which can be accomplished with an in situ generated alkyl-lithium.
Oxidation of o-Xylene to Phthalic Anhydride over V2O5/TiO2 Catalysts. II. Transient Catalytic Behaviour
Dias, Cristina R.,Portela, M. Farinha,Bond, Geoffrey C.
, p. 353 - 358 (1995)
The transient phase of the oxidation of o-xylene and o-tolualdehyde, before establishment of the steady state, has been studied over V2O5/TiO2 (anatase).At lower temperatures, an initial decrease in conversion and phthalic anhydride selectivity were observed, accompanied by an increase in selectivity to involatile products; at higher temperatures, the steady state was rapidly attained and no strong variations of conversion and selectivity were detected.For o-tolualdehyde oxidation, lower selectivities to involatile products were obtained, indicating that the adsorbed o-xylene molecules can lead more effectively to the formation of heavy organic compounds.Results obtained for selectivity to involatiles, time to reach steady state, and conversion indicate that catalyst deactivation can be ascribed to the formation of an organic residue on the catalyst surface.Such a residue can also desorb or undergo oxidation to CO2.
Oxidation of o-Xylene to Phthalic Anhydride over V2O5/TiO2 Catalysts. I. Influence of Catalyst Composition, Preparation Method and Operating Conditions on Conversion and Product Selectivities
Dias, Cristina R.,Portela, M. Farinha,Bond, Geoffrey C.
, p. 344 - 352 (1995)
The oxidation of o-xylene and of o-tolualdehyde over V2O5/TiO2 (anatase) catalysts has been studied at 533-633 K under steady state conditions; catalysts were prepared either by wet impregnation employing NH4VO3 solution or by a grafting technique with VO(O-i-C4H9)3.At lower temperatures and lower contact times, for both o-xylene and o-tolualdehyde, part of the reactant feed disappeared due to the formation of an involatile polymeric residue, the formation of which was enhanced at lower temperatures, lower contact times, and higher organic reactant concentrations.At lower contact times, the part of the residue deposited on the catalyst surface constituted an important CO2 source.The catalyst prepared by grafting showed higher phthalic anhydride selectivity and less of the residue.The formation of nonselective oxidation products seems to be favoured by uncoated TiO2 since 0.6percent V2O5/TiO2 showed higher CO2 selectivity than other catalysts.Crystalline V2O5 caused greater residue formation.
Supported ionic-liquid layer on polystyrene-TEMPO resin: A highly efficient catalyst for selective oxidation of activated alcohols with molecular oxygen
Liu, Lin,Liu, Dong,Xia, Zhiwei,Gao, Jiulin,Zhang, Tianlin,Ma, Juanjuan,Zhang, Dongen,Tong, Zhiwei
, p. 251 - 254 (2013)
We report a facile, efficient procedure for selective oxidation of activated alcohols by use of a novel supported ionic-liquid catalyst produced by coating polystyrene-TEMPO resin with the ionic liquid [bmim]PF6 and CuCl2. The oxidat
Confining task-specific ionic liquid in silica-gel matrix by sol-gel technique: A highly efficient catalyst for oxidation of alcohol with molecular oxygen
Liu, Lin,Ma, Juanjuan,Xia, Jiyin,Li, Luodan,Li, Chunlong,Zhang, Xiaobo,Gong, Junyan,Tong, Zhiwei
, p. 323 - 326 (2011)
A novel catalytic system was developed through confinement of TEMPO task-specific ionic liquid (TEMPO-IL) with CuCl2 in a silica-gel matrix by sol-gel technique. The obtained TEMPO-IL/CuCl2/silica-gel catalytic system was effective f
