25038-87-3Relevant articles and documents
Reactivity of Ionic Liquids: Reductive Effect of [C4C1im]BF4 to Form Particles of Red Amorphous Selenium and Bi2Se3 from Oxide Precursors
Knorr, Monika,Schmidt, Peer
, p. 125 - 140 (2021)
Temperature-induced change in reactivity of the frequently used ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate ([C4C1im]BF4) is presented as a prerequisite for the rational screening of reaction courses in material synthesis. [C4C1im]BF4 becomes active with oxidic precursor compounds in reduction reaction at ?≥200 °C, even without the addition of an external reducing agent. The reaction mechanism of forming red amorphous selenium from SeO2 is investigated as a model system and can be described similarly to the Riley oxidation. The reactive species but-1-ene, which is formed during the decomposition of [C4C1im]BF4, reacts with SeO2 and form but-3-en-2-one, water, and selenium. Elucidation of the mechanism was achieved by thermoanalytical investigations. The monotropic phase transition of selenium was analyzed by the differential scanning calorimetry. Beyond, the suitability of the single source oxide precursor Bi2Se3O9 for the synthesis of Bi2Se3 particles was confirmed. Identification, characterization of formed solids succeeded by using light microscopy, XRD, SEM, and EDX.
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Okada,Asami
, p. 333 (1973)
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Catalytic Synthesis of Vinyl Ketones over Metal Oxide Catalysts using Methanol as the Vinylating Agent
Ueda, Wataru,Yokoyama, Toshio,Moro-Oka, Yoshihiko,Ikawa, Tsuneo
, p. 39 - 40 (1984)
Basic binary iron-magnesium oxide has a marked catalytic activity on the vinylation of acetone with methanol to give methyl vinyl ketone.
The effects of ring size and substituents on the rates of acid-catalysed hydrolysis of five- and six-membered ring cyclic ketone acetals
Knowles, Jonathan P.,Whiting, Andrew
, p. 3365 - 3368 (2007)
A series of sterically similar five- and six-membered ring cyclic diol-derived ketone acetals have been prepared and their rates of acid-catalysed hydrolysis examined. The rates of hydrolysis are substantially affected by acetal ring conformational stereoelectronic effects and resonance effects depending upon the substituents on the parent ketone; an A1 mechanism of hydrolysis explains the observed effects. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.
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Sasson,Rempel
, p. 3825 (1974)
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Solvation changes accompanying proton transfer from a carbon acid to alkoxide bases as revealed by kinetic isotope effects
Casamassina, Thomas E.,Huskey, W. Phillip
, p. 14 - 20 (1993)
Primary hydrogen isotope effects are reported for the elimination of 4-nitrophenol from 4-(4-nitrophenoxy)-2-butanone in methanolic methoxide at 20°C and in aqueous hydroxide at 25°C. The isotope effects do not change significantly when the isotopic composition of the solvents is changed: (kH/kD)MeOH = 6.48 ± 0.22, (kHkD)MeOD = 6.40 ± 0.24; and (kH/kD)HOH = 7.54 ± 0.11, (kH/kD)DOD = 7.48 ± 0.21. Kinetic solvent isotope effects (using the undeuterated substrate) are kMeOD/kMeOH = 2.195 ± 0.064 and kDOD/kHOH = 1-526 ± 0.029. The experimental results are compared with model vibrational analysis calculations and about 60 literature examples of related solvent isotope effects on proton-transfer rates. The observations of primary hydrogen isotope effects that are unchanged upon isotopic substitution in protonic sites of the solvent were used to conclude that solvent reorganization is not coupled to proton transfer in the reaction coordinate.
Perspectives on the synthesis and use of ageladine A
Mordhorst, Thorsten,Bickmeyer, Ulf
, p. 4363 - 4366 (2015)
Focusing on the marine-derived alkaloid ageladine A ([4-(4,5-dibromo-1H-pyrrol-2-yl)]-1H-imidazo[4,5-c]pyridin-2-amine trifluoroacetate), we combined and modified published strategies to develop a synthesis method with easily managed reaction steps that allows gram-scale batch synthesis. On exploration additional features of the fluorescent properties of the compound were revealed. In tissues and cells of a marine flatworm, the emission profile shifted to longer wavelengths than in water. The fluorescence emission maximum shifted around 30-450 nm and the profile showed sufficient intensity at approximately 550 nm and above.
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Eadon,Shiekh
, p. 2288 (1974)
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Oxidative decarboxylation of levulinic acid by silver(I)/persulfate
Gong, Yan,Lin, Lu
, p. 2714 - 2725 (2011)
The oxidative decarboxylation of levulinic acid (LA) by silver(I)/persulfate [Ag(I)/S2O82-] has been investigated in this paper. The effects of buffer solution, initial pH value, time and temperature and dosages of Ag(I)/S2O8 2- on the decarboxylation of LA were examined in batch experiments and a reaction scheme was proposed on basis of the reaction process. The experimental results showed that a solution of NaOH-KH2PO4 was comparatively suitable for the LA decarboxylation reaction by silver(I)/persulfate. Under optimum conditions (temperature 160 °C, pH 5.0, and time 0.5 h), the rate of LA conversion in NaOH-KH2PO4 solutions with an initial concentration of 0.01 mol LA reached 70.2%, 2-butanone (methyl ethyl ketone) was the single product in the gas phase and the resulted molar yield reached 44.2%.
Oxidation of Ketones over Metal Oxide Catalysts. II. Biacetal Synthesis over Co3O4-Lanthanoid Oxide Catalysts
Takita, Yusaku,Hori, Fumiaki,Yamazoe, Noboru,Seiyama, Tetsuro
, p. 2757 - 2762 (1987)
The effects of the addition (10 atomicpercent) of lanthanoid oxides into Co3O4 on the oxidation of methyl ethyl ketone (MEK) were studied.The addition of La2O3 brought about marked enhancement of the rate of biacetyl (BA) formation.MEK conversion increased by a factor of 2.8 and the BA selectivity was improved at 450-500 K owing to the suppression of deep oxidation.The addition of CeO2 much improved the MEK conversion but BA selectivity decreased to less than 50percent and the scission reaction leading to acetaldehyde and acetic acid was enhanced.The addition of Pr6O11 improved MEK conversion but the addition of Nd2O3, Gd2O3, or Er2O3 showed little effect on MEK conversion.The reduction of both scission reaction and deep oxidation and the compensative increase in BA selectivities were observed.An approximately linear relationship was found between the specific rate of BA formation of the catalysts and logarithmic solubility product constants of hydroxydes of tervalent lanthanoid elements added, suggesting that the basicity of the catalysts is one of major factors for BA formation.The maximum efficiency (23.4percent) of BA formation was attained at a La content of ca. 10 at.percent.
Iridium-Catalyzed Hydrochlorination and Hydrobromination of Alkynes by Shuttle Catalysis
Yu, Peng,Bismuto, Alessandro,Morandi, Bill
supporting information, p. 2904 - 2910 (2020/01/25)
Described herein are two different methods for the synthesis of vinyl halides by a shuttle catalysis based iridium-catalyzed transfer hydrohalogenation of unactivated alkynes. The use of 4-chlorobutan-2-one or tert-butyl halide as donors of hydrogen halides allows this transformation in the absence of corrosive reagents, such as hydrogen halides or acid chlorides, thus largely improving the functional-group tolerance and safety profile of these reactions compared to the state-of-the-art. This method has granted access to alkenyl halide compounds containing acid-sensitive groups, such as tertiary alcohols, silyl ethers, and acetals. The synthetic value of those methodologies has been demonstrated by gram-scale synthesis where low catalyst loading was achieved.
TBN-Catalyzed Dehydrative N-Alkylation of Anilines with 4-Hydroxybutan-2-one
Cheng, Wenchen,Deng, Shue,Jiang, Liya,Ren, Lanhui,Wang, Zicheng,Zhang, Jian,Song, Weiguo
, p. 7372 - 7377 (2019/11/28)
Until now, the substitution of alcohols by N-nucleophiles via TBN-catalyzed dehydrogenation was not known. Herein, we reported a TBN catalyzed dehydrative N-alkylation of anilines with 4-hydroxybutan-2-one in the presence of TEMPO, which was different from the TEMPO/TBN catalyzed oxidation reactions. A range of anilines reacted successfully with 4-hydroxybutan-2-one to generate the N-monoalkylation products in good yields. Mechanistic studies revealed that this reaction most possibly proceeded through aza-Michael addition. Water was the only by-product, making it more environmentally friendly. The gram-scale reactions verified the synthetic practicality of this protocol.
