1460-57-7Relevant articles and documents
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Winstein
, p. 2792,2794 (1942)
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Cu(II)-amino acid–CaAl-layered double hydroxide complexes, recyclable, efficient catalysts in various oxidative transformations
Varga, Gábor,Ziegenheim, Szilveszter,Muráth, Szabolcs,Csendes, Zita,Kukovecz, ákos,Kónya, Zoltán,Carlson, Stefan,Korecz, László,Varga, Erika,Pusztai, Péter,Sipos, Pál,Pálinkó, István
, p. 49 - 60 (2016)
Intercalated composite materials were prepared with CaAl-layered double hydroxide as host and Cu(II)-amino acid (L-cysteine, L-histidine and L-tyrosine) complex anions as guests. Two methods (intercalation of the ligand first followed by constructing the complex; preforming the complex first, then introducing it among the layers of the host) and optimization of the synthesis conditions were performed to obtain composites having the complex exclusively among the layers. The composite materials were structurally characterized by powder X-ray diffractometry, mid infrared (IR) spectroscopy with ATR (attenuated total reflectance) or photoacoustic detections, transmission and scanning electron microscopies and X-ray photoelectron spectroscopy. Structural features of the intercalant (coordination number, coordination sites) were elucidated by classical chemical and energy dispersive X-ray analyses, EPR (electron paramagnetic spectroscopy), X-ray absorption and far IR spectroscopies. Structural models based on these methods are also given. Catalytic activities, selectivities and recycling abilities of the substances were studied in the oxidation reactions of cyclohexene with peracetic acid and in situ formed iodosylbenzene as oxidants in the liquid phase. The catalysts were active in the Ullmann coupling reaction as well. The intercalated substances were found to be efficient and highly selective catalysts with very good recycling abilities.
Regioselective O2′,O3′-deacetylations of peracetylated ribonucleosides by using tetra-n-butylammonium fluoride
Babu Kumar, Arun,Manetsch, Roman
, p. 3551 - 3555 (2014)
A robust, mild, and highly regioselective deacetylation of 1,2-diol diacetates in the presence of other acetate functions was achieved by using tetra-n-butylammonium fluoride. This method provided a single-step route to access O5′-acetyl ribonucleosides, a key intermediate in the synthesis of biomedically important nucleosides and nucleotides. Moreover, it offered the general applicability of a non-enzymatic method for the selective deacetylation of peracetylated 2′-deoxyribonucleosides. Its synthetic utility was further demonstrated by the synthesis of molecules of biomedical interest by using this particular deacetylation reaction. Copyright
Supported sub-nanometer Ta oxide clusters as model catalysts for the selective epoxidation of cyclooctene
Zwaschka,Rondelli,Krause,R?tzer,Hedhili,Heiz,Basset,Schweinberger,D'Elia
, p. 3035 - 3041 (2018)
The preparation of organic ligand-free, isolated tantalum oxide complexes (Ta1) and small clusters (Tan>1) on flat silicate supports was accomplished by ultra-high vacuum (UHV) techniques followed by oxidation in air. The resulting s
Cyclohexene epoxidation with H2O2in the vapor and liquid phases over a vanadium-based metal-organic framework
Ahn, Sol,Bae, Youn-Sang,Farha, Omar K.,Kim, Ah-Reum,Notestein, Justin M.,Yoon, Tae-Ung
, p. 4580 - 4585 (2020)
A metal-organic framework, MIL-47(V) containing coordinatively saturated V+IV sites linked together by terephthalic linkers, was prepared by a solvothermal method and evaluated as a catalyst in the epoxidation of cyclohexene. We have compared the catalytic activity in the condensed and gas phase oxidation of cyclohexene to discuss the effect of temperature and reaction phase in cyclohexene epoxidation over MIL-47(V). The catalysts were examined for the epoxidation of cyclohexene with H2O2 at 50, 65, 120, and 150 °C. We observed significant differences in product selectivity between liquid-phase and gas-phase operations and confirmed that the active sites are tightly incorporated into the MOF as node channels and thus resistant to leaching.
Highly efficient room-temperature oxidation of cyclohexene and d-glucose over nanogold Au/SiO2 in water
Bujak, Piotr,Bartczak, Piotr,Polanski, Jaroslaw
, p. 15 - 21 (2012)
Silica-supported nanogold catalysts suspended in 30% hydrogen peroxide using ultrasound are highly active and selective for cyclohexene and d-glucose oxidation at room temperature. In these conditions a polar reactant, D-glucose, can be efficiently and directly converted with 100% yield using this system, while a conversion of apolar cyclohexene is limited by the addition of a surfactant improving cosolubility in the system and/or catalyst/support wettability. To our best knowledge this is the first time that hydrogen peroxide has been used efficiently in association with a gold catalyst for the selective oxidation of cyclohexene in a biphasic system.
Mechanistic studies on the roles of the oxidant and hydrogen bonding in determining the selectivity in alkene oxidation in the presence of molybdenum catalysts
Chandra, Prakash,Pandhare, Swati L.,Umbarkar, Shubhangi B.,Dongare, Mohan K.,Vanka, Kumar
, p. 2030 - 2040 (2013)
When the molybdenum oxo(peroxo) acetylide complex [CpMo(O-O)(O)C≡CPh] is used as a catalyst for the oxidation of olefins, completely different product selectivity is obtained depending on the oxidant employed. When tert-butyl hydroperoxide (TBHP, 5.5 M) in dodecane is used as the oxidant for the oxidation of cyclohexene, cyclohexene oxide is formed with high selectivity. However, when H2O2 is used as the oxidant, the corresponding cis-1,2-diol is formed as the major product. Calculations performed by using density functional theory revealed the nature of the different competing mechanisms operating during the catalysis process and also provided an insight into the influence of the oxidant and hydrogen bonding on the catalysis process. The mechanistic investigations can therefore serve as a guide in the design of molybdenum-based catalysts for the oxidation of olefins. Copyright
Effect of the reaction conditions on the epoxidation of alkenes with hydrogen peroxide catalyzed by silica-supported titanium derivatives
Fraile, Jose M.,Garcia, Jose I.,Mayoral, Jose A.,Vispe, Eugenio
, p. 146 - 156 (2001)
Silica-supported titanium catalysts are active in the epoxidation of cyclohexene with diluted hydrogen peroxide at 80°C. At low H2O2/Ti ratio the contribution of the direct mechanism of epoxidation is important, around 40% of the productive H2O2 conversion and 60% of the epoxidation reaction. However, the increase in H2O2/Ti ratio modifies these results. The contribution of the direct epoxidation to H2O2 conversion is reduced to 20-30%, whereas contribution to epoxidation is kept in the range 40-60%. Neither the silanization of the silica surface nor the substitution of the isopropoxy groups by tartaric acid improves the behavior of the solid in these conditions. However, the simultaneous variation in hydrophilic character of the surface and titanium environment increases the contribution of the direct epoxidation. In contrast, the increase in H2O2/Ti ratio reduces the epoxide hydrolysis. The catalysts lose some titanium after reaction, but in general they show higher stability than closely related solids. The activity for direct and radical contributions changes after recovering, showing the important change in nature of the catalytic sites, which are not easily regenerated by extensive washing with different solvents. In any case, with cyclooctene, an alkene that does not form radicals, the activity for direct epoxidation shows a decline in every recycling but final turnover numbers are similar in the first three runs, showing high stability of the titanium on the solid.
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Blount,Robinson
, p. 1429,1431 (1932)
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Photo-Induced Dihydroxylation of Alkenes with Diacetyl, Oxygen, and Water
Masuda, Yusuke,Ikeshita, Daichi,Murakami, Masahiro
, (2021/02/09)
Herein reported is a photo-induced production of vicinal diols from alkenes under mild reaction conditions. The present dihydroxylation method using diacetyl (= butane-2,3-dione), oxygen, and water dispenses with toxic reagents and intractable waste generation.
