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.
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.
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. 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.
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
α-MnO2 modified exfoliated porous g-C3N4 nanosheet (2D) for enhanced photocatalytic oxidation efficiency of aromatic alcohols
Nanda, Binita,Nanda, Braja B.,Pradhan, Manas Ranjan,Rath, Dharitri,Sethi, Ratikanta
, (2021/06/18)
Porous graphitic carbon nitride (g-C3N4) was synthesized by taking melamine and ammonium bicarbonate through single-step calcination method followed by ultrasonication to obtain exfoliated porous g-C3N4 (2D) nanosheets. Further enhancement of photocatalytic performance, g-C3N4 nanosheet (2D) was further modified with different weight percentage of (1, 3, 5, and 7) of MnO2. The introduction of α-MnO2 onto the g-C3N4 nanosheet establishes an interlayer channels to promote the migration of charge carriers through the valence band and conduction band of the prepared composite MnO2@g-C3N4. The transformation of photo induced charge carriers adopt the Z-scheme mechanism rather band-transfer mechanism. The accumulated photo generated electrons in conduction band of g-C3N4 is more electro negative than the potential of (O2/O2–.) and able to reduce oxygen to superoxide (O2–.) radical. At the same time, the holes in valence band of α-MnO2 are more electro positive than the potential of (OH–/OH.) and help in oxidate OH– to hydroxyl (OH.) radical. Among all the composites, 3 wt% MnO2 modified g-C3N4 shows the best photocatalytic oxidation efficiency towards all the aromatic alcohols. In presence of visible light, heterojuction formation, and formation of active charged species (OH. and O2–.) were mostly responsible for photocatalytic oxidation of aromatic alcohols through free radical mechanism.
A green approach for aerobic oxidation of benzylic alcohols catalysed by CuI-Y zeolite/TEMPO in ethanol without additional additives
Senthilkumar, Samuthirarajan,Zhong, Wei,Natarajan, Mookan,Lu, Chunxin,Xu, Binyu,Liu, Xiaoming
, p. 705 - 713 (2021/01/25)
An efficient and green protocol for aerobic oxidation of benzylic alcohols in ethanol using CuI-Y zeolite catalysts assisted by TEMPO (TEMPO = 2,2,6,6-tetramethyl-1-piperidine-N-oxyl) as the radical co-catalyst in the presence of atmospheric air under mild conditions is reported. The CuI-Y zeolite prepared via ion exchange between CuCl and HY zeolite was fully characterized by a variety of spectroscopic techniques including XRD, XPS, SEM, EDX and HRTEM. The incorporation of Cu(i) into the 3D-framework of the zeolite rendered the catalyst with good durability. The results of repetitive runs revealed that in the first three runs, there was hardly a decline in activity and a more substantial decrease in yield was observed afterwards, while the selectivity remained almost unchanged. The loss in activity was attributed to both the formation of CuO and the bleaching of copper into the liquid phase during the catalysis, of which the formation of CuO was believed to be the major contributor since the bleaching loss for each run was negligible (2%). In this catalytic system, except TEMPO, no other additives were needed, either a base or a ligand, which was essential in some reported catalytic systems for the oxidation of alcohols. The aerobic oxidation proceeded under mild conditions (60 °C, and 18 hours) to quantitatively and selectively convert a wide range of benzylic alcohols to corresponding aldehydes, which shows great potential in developing green and environmentally benign catalysts for aerobic oxidation of alcohols. The system demonstrated excellent tolerance against electron-withdrawing groups on the phenyl ring of the alcohols and showed sensitivity to steric hindrance of the substrates, which is due to the confinement of the pores of the zeolite in which the oxidation occurred. Based on the mechanism reported in the literature for homogenous oxidation, a mechanism was analogously proposed for the aerobic oxidation of benzylic alcohols catalysed by this Cu(i)-containing zeolite catalyst. This journal is
Ferric ion concentration-controlled aerobic photo-oxidation of benzylic C–H bond with high selectivity and conversion
Bu, Hongzhong,Gu, Jiefan,Li, Yufeng,Ma, Hongfei,Wan, Yuting,Wu, Zheng-Guang,Zhang, Weijian,Zhou, Ying'ao,Zhu, Hongjun
, (2021/07/16)
A Fe(III)-promoted highly selective photo-oxidation of benzylic C–H bond delivering relative carbonyl products is reported. By altering the concentration of ferric salt, methylarenes can be selectively oxidized under UV irradiation to furnish aromatic aldehydes or acids, respectively. By this protocol, the oxidation of ethylarenes provides the corresponding acetophenones. The reaction is inferred to involve divergent pathways in different concentrations of catalyst for the alternative selectivity between aldehydes and aicds. The reusable catalyst, high conversion and selectivity make this oxidation a green and economic protocol for the synthesis of aromatic carbonyl compounds.