- Efficient Cleavage of Cyclopropyl Bond by Adjacent Ketyl Radical Generated Under PET Conditions
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Photolysis of various conjugated cyclopropyl and epoxy ketones in 20percent triethyl amine (TEA) and ethanol leads to cleavage of cyclopropyl bond.Significant wavelength dependence phenomenon is observed during photolysis for the cleanliness and efficient photo transformation.Steroidal cyclopropyl ketones cleave efficiently at 300nm photolysis, whereas exo-cyclopropyl ketones cleave at 254nm.The regiochemistry of cyclopropyl bond cleavage is governed by the principle of maximum overlap.The nature of chemistry generated by ketyl radical is shown to be a function of methodology of their generation.
- Pandey, Bipin,Rao, Ashok T.,Dalvi, Pramod V.,Kumar, Pradeep
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- Supported mesoporous solid base catalysts for condensation of carboxylic acids
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New mesoporous base catalysts (CM-HMS and CM-MCM-41) were synthesized by generating uniform particles of cerium and manganese oxides (MnO x/CeO2) in situ within hexagonal mesoporous silica (HMS) and MCM-41 supports. These catalysts were characterized by N2 adsorption, X-ray diffraction (XRD), transmission electron microscopy (TEM), energy-dispersive X-ray spectrometry (EDX), FTIR, temperature-programmed desorption of CO2 (CO2-TPD), and diffuse reflectance UV-visible (UV-vis) spectroscopy. Spectroscopic studies reveal that some particles of MnOx/CeO2 are incorporated into the walls of the silica network of HMS and MCM-41, while others are highly dispersed onto the surface of the HMS or MCM-41. The catalytic activity of CM-HMS and CM-MCM-41 for the ketonization of carboxylic acids was confirmed; better utilization of Ce and Mn was observed than in unsupported MnOx/CeO2. The citrate-based preparation of MnOx/CeO2 catalyst supported on HMS and MCM-41 has not been previously reported in the literature.
- Murkute, Ambareesh D.,Jackson, James E.,Miller, Dennis J.
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- CONFIGURATIONAL PRODUCT CONTROL IN REACTIONS OF TRANS- AND CIS-DIALKYLBIS(TERTIARY PHOSPHINE)PALLADIUM(II) WITH CARBON MONOXIDE. EVIDENCE SUPPORTING AN ALKYL MIGRATION MECHANISM IN CO INSERTION INTO Pd-C BOND
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Reactions of trans- and cis-PdR2L2 (R = Me, Et, Pr, and Bu; L = tertiary phosphine ligands) with carbon monoxide in solutions were found to give strikingly different products depending on the configurations of the dialkylpalladium complexes.The results can be explained by assuming reactions proceeding by alkyl migration mechanisms.
- Ozawa, Fumiyuki,Yamamoto, Akio
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- Hydroformylation of Propene with Zeolite-supported Rhodium Phosphine Complexes
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Rhodium phosphine complexes synthesized in situ on zeolite NaY are active for propene hydroformylation at 150 deg C and 1 atm; the catalysts are not stable yet show an enhancement in linear vs. branched products with an increased production of alcohols compared to rhodium zeolites without phosphines.
- Rode, Edward,Davis, Mark E.,Hanson, Brian E.
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- Rhodium Zeolites as Bifunctional Catalysts for the Synthesis of 2-Methylhexan-3-one and Heptan-4-one from Propylene, Carbon Monoxide, and Hydrogen
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RhNaX and RhNaY zeolites behave as bifunctional catalysts for the synthesis of C7 ketones from C3H6, CO, and H2 at atmospheric pressure and 120-150 deg C.
- Rode, Edward,Davis, Mark E.,Hanson, Brian E.
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- Experimental and theoretical assessment of the mechanism and site requirements for ketonization of carboxylic acids on oxides
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Ketonization of carboxylic acids removes O-atoms and forms new CC bonds, thus providing routes from sustainable carbon feedstocks to fuels and chemicals. The elementary steps involved and their kinetic relevance, as well as the number and nature of the active sites on active TiO2 and ZrO2 catalysts, remain matters of active discourse. Here, site titrations demonstrate the requirement for coordinatively-unsaturated M-O-M sites (M?=?Ti, Zr) with specific geometry and intermediate acid-base strength. The measured site densities allow rigorous reactivity comparisons among catalysts based on turnover rates and activation free energies, as well as the benchmarking of mechanistic proposals against theoretical assessments. Kinetic, isotopic, spectroscopic, and theoretical methods show that C2C4 acids react on anatase TiO2 via kinetically-relevant CC coupling between 1-hydroxy enolate species and coadsorbed acids bound at vicinal acid-base pairs saturated with active monodentate carboxylates. Smaller TiTi distances on rutile TiO2 lead to the prevalence of unreactive bidentate carboxylates and lead to its much lower ketonization reactivity than anatase. The prevalent dense monolayers of chemisorbed acid reactants reflect their strong binding at acid-base pairs and their stabilization by H-bonding interactions with surface OH groups derived from the dissociation of the carboxylic acids or the formation of 1-hydroxy enolates; these interactions also stabilize CC coupling transition states preferentially over their carboxylate precursors; high coverages favor sequential dehydration routes of the α-hydroxy-γ-carboxy-alkoxide CC coupling products over previously unrecognized concerted six-membered-ring transition states. Infrared spectra show that ubiquitous deactivation, which has precluded broader deployment of ketonization in practice and unequivocal mechanistic inquiries, reflects the gradual formation of inactive bidentate carboxylates. Their dehydration to ketene-like gaseous species is faster on anatase TiO2 than on ZrO2 and allows the effective scavenging of bidentate carboxylates via ketene hydrogenation to alkanals/alkanols on a Cu function present within diffusion distances. These strategies make anatase TiO2, a more effective catalyst than ZrO2, in spite of its slightly lower initial turnover rates. This study provides details about the mechanism of ketonization of C2C4 carboxylic acids on TiO2 and a rigorous analysis of the sites required and of active and inactive bound species on TiO2 and ZrO2. The preference for specific distances and for intermediate acid-base strength in M-O-M species is consistent with the structure and energy of the proposed transition states and intermediates; their relative stabilities illustrate how densely-covered surfaces, prevalent during ketonization catalysis, represent an essential requirement for the achievement of practical turnover rates.
- Wang, Shuai,Iglesia, Enrique
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- Reaction kinetics and mechanism of ketonization of aliphatic carboxylic acids with different carbon chain lengths over Ru/TiO2 catalyst
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A kinetics study of the ketonization of carboxylic acids with varying alkyl chain lengths (acetic, propionic, and butyric) has been conducted on a pre-reduced Ru/TiO2 catalyst. A thorough analysis built upon a Langmuir-Hinshelwood (LH) model and transition state theory (TST) shows that the reaction follows a second-order expression with respect to the surface coverage of carboxylic acids. The heats of adsorption are very similar for the three different acids and independent of the carbon chain length. Moreover, they are significantly higher than those of the reaction products, that is, ketone, water, and CO2. At the same time, the change in adsorption entropy of the acids (in absolute value) with respect to the gas phase was found to decrease with increasing alkyl chain length. These results are consistent with a strongly adsorbed bidentate configuration, in which the main interaction with the surface is via the carboxylic group while the alkyl group moves rather freely. Application of the LH model in the fitting of the reaction data at varying temperatures allowed us to calculate the true activation energy and the activation entropy of the reaction. Both were found to increase with increasing carbon chain length of the acids. This compensation effect can be interpreted in terms of the nature of the transition state. It is concluded that ketonization proceeds through a β-ketoacid intermediate with an early transition state, in which the formation of the C-C bond is the rate-limiting step.
- Pham, Tu N.,Shi, Dachuan,Resasco, Daniel E.
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- SELECTIVE FORMATION OF KETONES FROM PROPENE, CO AND H2O : COBALT BASED CATALYTIC HYDROCARBONYLATION
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A complex prepared in situ from Co2(CO)8 and 1,2-bis(diphenylphosphino)ethane (diphos) was found to be an effective catalyst for selective hydrocarbonylation of propene to give dipropyl ketones.
- Murata, Kazuhisa,Matsuda, Akio
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- Highly Efficient Abnormal NHC Ruthenium Catalyst for Oppenauer-Type Oxidation and Transfer Hydrogenation Reactions
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The ruthenium complex [Ru(OAc)(a-PC)2]Br (3) containing two abnormal NHC ligands is obtained by reaction of Ru(OAc)2(PPh3)2 (1) with 1-(2-diphenylphosphinoethyl)-3-mesitylimidazolium bromide in the presence of NaOAc. Complex 3 catalyzes the Oppenauer-type oxidation of a number of alcohols at unrivalled reaction rates reaching TOFs up to 550 000 h-1, at low catalyst loadings (S/C higher than 10 000) and using acetone in stoichiometric amounts. Complex 3 is also highly active in the reverse transfer hydrogenation of several ketones with 2-propanol, displaying TOFs up to 600 000 h-1
- Pardatscher, Lorenz,Hofmann, Benjamin J.,Fischer, Pauline J.,H?lzl, Sebastian M.,Reich, Robert M.,Kühn, Fritz E.,Baratta, Walter
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- Kinetics of the gas-phase reactions of NO3 radicals with a series of alcohols, glycol ethers, ethers and chloroalkenes
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Using a relative rate method, rate constants have been measured for the gas-phase reactions of the NO3 radical with methacrolein, a series of ethers, glycol ethers, alcohols and chloroalkenes at 298 ± 2 K and atmospheric pressure of air. The rate constants determined (in units of 10-16 cm3 molecule-1 s-1) were: methacrolein, 33 ± 10; diethyl ether, 31 ± 10; di-n-propyl ether, 49 ± 16; diisopropyl ether, 40 ± 13; ethyl tert-butyl ether, 45 ± 14; 1-methoxypropan-2-ol, ≤15 ± 5; 2-butoxyethanol, ≤31 ± 11; propan-1-ol, ≤21 ± 8; propan-2-ol, ≤17 ± 6; butan-1-ol, ≤27 ± 10; butan-2-ol, ≤25 ± 8; heptan-4-ol, ≤60 ± 20; cis-1,2-dichloroethene, 1.3 ± 1.3; 1,1-dichloroethene, 18-6+9; trichloroethene, 3.6-1.5+2.0; tetrachloroethene, -2.0+3.0. Carbonyl products of the alcohol reactions arising after H-atom abstraction at the carbon atom to which the -OH group is attached were observed, and rate constants for this reaction pathway obtained. Significant discrepancies with the literature concern propan-2-ol, ethyl tert-butyl ether and 3-chloropropene, with our relative rate constants for these compounds being factors of ca. 2, ca. 2, and ca. 8 lower, respectively, than previously reported absolute rate constant determinations.
- Chew, Andrew A.,Atkinson, Roger,Aschmann, Sara M.
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- Oxidation of secondary alkanols with the system cerium ammonium nitrate-lithium bromide into ketones, α-bromo ketones, and α,α -dibromo ketones
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Oxidation of secondary alkanols with the system Ce(NH4) 2(NO3)6-LiBr in aqueous acetonitrile gave ketones, α-bromo ketones, or α,α-dibromo ketones. The selectivity of the reaction under standard conditions depends only on the molar ratio of the reagents (alkanol : CeIV : LiBr).
- Nikishin,Sokova,Kapustina
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- A simple procedure for the oxidation of alcohols using [bis(acetoxy)iodo]benzene and a catalytic amount of bromide ions in ethyl acetate
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Abstract Primary and secondary benzylic alcohols and secondary aliphatic alcohols were oxidized to the corresponding aldehydes and ketones by using [bis(acetoxy)iodo]benzene (BAIB) and a catalytic amount of bromide ions, from tetrabutylammonium bromide or KBr, in ethyl acetate. The catalytic role of the bromide ions was also highlighted in the oxidation of primary aliphatic alcohols and secondary allylic alcohols carried out in the presence of 1 mol% TEMPO.
- Salvo, Anna Maria Pia,Campisciano, Vincenzo,Beejapur, Hazi Ahmad,Giacalone, Francesco,Gruttadauria, Michelangelo
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- Fully Substituted Conjugate Benzofuran Core: Multiyne Cascade Coupling and Oxidation of Cyclopropenone
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An unprecedented C═C double bond cleavage of cyclopropenone and dioxygen activation by multiyne cascade coupling has been developed. This chemistry provides a novel, simple, and efficient approach to synthesize fully substituted conjugate benzofuran derivatives from simple substrates under mild conditions. The density functional theory (DFT) calculations reveal that the unique homolytic cleavages of cyclopropenone and molecular oxygen are crucial to the success of this reaction.
- Yao, Liangliang,Hu, Qiong,Bao, Li,Zhu, Wenjing,Hu, Yimin
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supporting information
p. 4971 - 4975
(2021/06/30)
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- METHOD FOR PRODUCING CARBONATE DERIVATIVE
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The objective of the present invention is to provide a method for producing a polycarbonate safely and efficiently even without using a base. The method for producing a carbonate derivative according to the present invention is characterized in comprising the step of irradiating a high energy light to a composition comprising the halogenated methane and the hydroxy group-containing compound in the presence of oxygen, wherein a molar ratio of a total usage amount of the hydroxy group-containing compound to 1 mole of the halogenated methane is 0.05 or more.
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Paragraph 0122-0123
(2022/01/04)
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- METHOD FOR PRODUCING BIO ALCOHOL FROM INTERMEDIATE PRODUCTS OF ANAEROBIC DIGESTION TANK
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The present invention relates to a method for producing a bio-alcohol by reacting a mixture of volatile fatty acid with methanol in 2 through 11 in a reactor in the presence of a 280 °C-membered alkaline earth metal catalyst or 400 °C transition metal catalyst formed based on a support.
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Paragraph 0043-0048
(2021/05/25)
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- Robust Mn(iii): N -pyridylporphyrin-based biomimetic catalysts for hydrocarbon oxidations: heterogenization on non-functionalized silica gel versus chloropropyl-functionalized silica gel
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Two classes of heterogenized biomimetic catalysts were prepared and characterized for hydrocarbon oxidations: (1) by covalent anchorage of the three Mn(iii) meso-tetrakis(2-, 3-, or 4-pyridyl)porphyrin isomers by in situ alkylation with chloropropyl-functionalized silica gel (Sil-Cl) to yield Sil-Cl/MnPY (Y = 1, 2, 3) materials, and (2) by electrostatic immobilization of the three Mn(iii) meso-tetrakis(N-methylpyridinium-2, 3, or 4-yl)porphyrin isomers (MnPY, Y = 4, 5, 6) on non-modified silica gel (SiO2) to yield SiO2/MnPY (Y = 4, 5, 6) materials. Silica gel used was of column chromatography grade and Mn porphyrin loadings were deliberately kept at a low level (0.3% w/w). These resulting materials were explored as catalysts for iodosylbenzene (PhIO) oxidation of cyclohexane, n-heptane, and adamantane to yield the corresponding alcohols and ketones; the oxidation of cyclohexanol to cyclohexanone was also investigated. The heterogenized catalysts exhibited higher efficiency and selectivity than the corresponding Mn porphyrins under homogeneous conditions. Recycling studies were consistent with low leaching/destruction of the supported Mn porphyrins. The Sil-Cl/MnPY catalysts were more efficient and more selective than SiO2/MnPY ones; alcohol selectivity may be associated with hydrophobic silica surface modification reminiscent of biological cytochrome P450 oxidations. The use of widespread, column chromatography, amorphous silica yielded Sil-Cl/MnPY or SiO2/MnPY catalysts considerably more efficient than the corresponding, previously reported materials with mesoporous Santa Barbara Amorphous No 15 (SBA-15) silica. Among the materials studied, in situ derivatization of Mn(iii) 2-N-pyridylporphyrin by covalent immobilization on Sil-Cl to yield Sil-Cl/MnP1 showed the best catalytic performance with high stability against oxidative destruction and reusability/recyclability.
- Pinto, Victor Hugo A.,Falc?o, Nathália K. S. M.,Mariz-Silva, Bárbara,Fonseca, Maria Gardennia,Rebou?as, Júlio S.
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supporting information
p. 16404 - 16418
(2020/12/03)
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- Upgrading 1-butanol to unsaturated, carbonyl and aromatic compounds: A new synthesis approach to produce important organic building blocks
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Unsaturated, carbonyl and aromatic products were obtained by reacting 1-butanol or a 1-butanol:methanol mixture with a copper mixed metal oxide catalyst in a fixed bed reactor. The selectivities observed, mostly for the unsaturated and carbonyl products, can represent a new alternative and greener pathway for the production of fine-chemicals and organic building blocks.
- Boscolo, Mauricio,Metzker, Gustavo,Mora Vargas, Jorge,Orduna Ortega, Julieth,Tofaneli Morelato, Luiz Henrique
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supporting information
p. 2365 - 2369
(2020/05/13)
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- A method for the preparation of aldehydes
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The invention discloses a method for the preparation of ketone, relates to the field of organic synthesis. This invention adopts the organic solvent as a medium, cyclopropene [...] derivative as an active agent, activated DMSO oxidation [...] oxidation. The method of the invention is simple, easy to operate, rapid reaction rate, mild reaction, the reaction rate can be adjusted, more economic, to achieve industrial laid the foundation.
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Paragraph 0128; 0129
(2019/05/28)
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- Cyclopropenium-Activated DMSO for Swern-Type Oxidation
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Swern oxidation is widely used to convert alcohols into their corresponding carbonyl compounds. However, the conventional method with use of the volatile oxalyl chloride as an activator requires the reaction to be conducted below -60 °C. We discovered that 3,3-dichloro-1,2-diphenylcyclopropene (DDC) can be used as a new activator for Swern-type oxidations of alcohols, which can be conducted at -20 °C. This new protocol features mild and fast reactions with easy operation. Furthermore, the activator DDC is easy to handle, and diphenylcyclopropenone can be recovered quantitively. This new type of Swern oxidation shows a broad scope of substrates including benzylic, allylic, aliphatic, and biobased alcohols, and gives high yields of up to 93%.
- Guo, Tianfo,Gao, Yu,Li, Zhenjiang,Liu, Jingjing,Guo, Kai
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supporting information
p. 329 - 332
(2019/02/12)
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- OZONE-FACILITATED SELECTIVE OXIDATION OF ALKANES IN LIQUID CARBON DIOXIDE
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A process for the ozonolysis of an alkane may comprise combining an alkane and ozone in a liquid phase medium comprising CO2 under conditions sufficient to oxidize the alkane to produce one or more non-combustion products. The liquid phase medium may be free of a super acid.
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Paragraph 0037
(2018/03/06)
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- Methods to produce fuels
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The present disclosure generally relates to the catalytic conversion of alcohols into hydrocarbon ketones suitable for use as fuels. More specifically, the present disclosure relates to the catalytic conversion of a mixture of isopropanol-butanol-ethanol (IBE) or acetone-butanol-ethanol (ABE), into ketones suitable for use as fuels. The ABE or IBE mixtures may be obtained from the fermentation of biomass or sugars.
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Page/Page column 37-39
(2018/02/28)
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- NaBrO3/bmim[HSO4]: a versatile system for the selective oxidation of 1,2-diols, α-hydroxyketones, and alcohols
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Abstract: Sodium bromate with bmim[HSO4] has been found to be an excellent oxidizing agent in aqueous medium. NaBrO3:bmim[HSO4] oxidized 1,2-diols, α-hydroxyketones, and alcohols to the corresponding carbonyl compounds in excellent yields. This method offers advantages such as low cost reagents, aqueous reaction conditions, moderate temperatures and short reaction times and hence environmentally benign reaction. Moreover, the ionic liquid bmim[HSO4] could be recycled for at least three times without loss of significant activity. Graphical abstract: [Figure not available: see fulltext.]
- Khurana, Jitender M.,Lumb, Anshika,Chaudhary, Ankita
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p. 381 - 386
(2017/02/10)
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- Alcohol Oxidations Using Reduced Polyoxovanadates
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A full account of our recently communicated room temperature alcohol oxidation using reduced polyoxovanadates (r-POVs) is presented. Extensive optimizations revealed optimal conditions employing 0.02 equiv. of r-POV catalyst Cs5(V14As8O42Cl), 5 equiv. tert-butyl hydrogen peroxide (tBuOOH) as the terminal co-oxidant, in an acetone solvent for the quantitative oxidation of aryl-substituted secondary alcohols to their ketone products. The substrate scope tolerates most aryl substituted secondary alcohols in good to quantitative yields while alkyl secondary and primary activated alcohols were sluggish in comparison under similar conditions. Catalyst recyclability was successful on a 1.0?mmol scale of starting alcohol 1-phenylethanol. The oxidation was also successfully promoted by the VIV/VV mixed valent polyoxovanadate (POV) Cs11Na3Cl5(V15O36Cl). Finally, a third POV, Cs2.64(V5O9)(AsO4)2, was investigated for catalytic activity using our established reaction protocol, but proved ineffective as compared to the other two r-POV catalysts. This study expands the field of POM-mediated alcohol oxidations to include underexplored r-POV catalysts. While our catalysts do not supplant the best catalysts known for the transformation, their study may inform the development of other novel oxidative transformations mediated by r-POVs.
- Campbell, McKenzie L.,Sulejmanovic, Dino,Schiller, Jacqueline B.,Turner, Emily M.,Hwu, Shiou-Jyh,Whitehead, Daniel C.
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- Synthesis of Mono- and Dinuclear Vanadium Complexes and Their Reactivity toward Dehydroperoxidation of Alkyl Hydroperoxides
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Several vanadium(V) complexes with either dipic-based or Schiff base ligands were synthesized. The complexes were fully characterized by elemental analysis, IR, 1H, 13C, and 51V NMR spectroscopy, as well as mass spectrometry and X-ray diffraction. Furthermore, they were tested toward their catalytic deperoxidation behavior and a significant difference between 4-heptyl hydroperoxide and cyclohexyl hydroperoxide was observed. In the case of 4-heptyl hydroperoxide, the selectivity toward the corresponding ketone was higher than with cyclohexyl hydroperoxide. DFT calculations performed on the vanadium complex showed that selective decomposition of secondary hydroperoxides with vanadium(V) to yield the corresponding ketone and water is indeed energetically feasible. The computed catalytic path, involving cleavage of the O-O bond, hydrogen transfer, release of ketone/water, and finally addition of hydroperoxide, can proceed without the generation of radical species.
- Schmidt, Anna-Corina,Hermsen, Marko,Rominger, Frank,Dehn, Richard,Teles, Joaquim Henrique,Sch?fer, Ansgar,Trapp, Oliver,Schaub, Thomas
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supporting information
p. 1319 - 1332
(2017/02/15)
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- Effect of cis/trans isomerism on selective oxidation of olefins with nitrous oxide
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Liquid phase oxidation of olefins with nitrous oxide is a promising synthetic route to ketones. The effect of cis/trans isomerism on the reactivity of olefins towards N2O and on the reaction mechanism was studied for the first time using 3-heptene oxidation as an example. Our experimental study revealed that cis- and trans-isomers of 3-heptene have similar reactivity and yield the same set of products. However, the cis/trans isomerism of the olefin has a pronounced effect on the reaction route involving the cleavage of the initial C=C bond and, accordingly, on the products ratio. The yield of ketones is lower for the trans-isomer due to higher contribution of the cleavage route.
- Ivanov, Dmitry,Babushkin, Dmitry,Semikolenov, Sergey,Malykhin, Sergey,Kharitonov, Alexander,Dubkov, Konstantin
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p. 2501 - 2506
(2016/04/26)
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- Catalytic alkylation of acetone with ethanol over Pd/carbon catalysts in flow-through system via borrowing hydrogen route
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Consecutive alkylation of acetone with ethanol as model reactants was studied in order to obtain biomass based fuels by continuous processing of acetone-butanol-ethanol (ABE) mixture. Butanol, which can inevitably form as Guerbet side product in a self-aldol reaction of ethanol was not applied in our study as an initial component, in order to follow the complexity of the reaction mechanism. A flow-through reactor was applied with inert He or reducing H2 stream in the temperature range of 150-350°C. Efficient catalysts containing Pd and base (K3PO4 or CsOH) crystallites were prepared applying commercial activated carbon (AC) support. The catalyst beds were pre-treated in H2 flow at 350°C. Mono- or dialkylated ketones were formed with high yields and these products could be reduced only to alcohols over palladium.
- Novodárszki, Gyula,Onyestyák, Gy?rgy,Wellisch, ágnes Farkas,Pilbáth, Aranka
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p. 251 - 257
(2016/07/06)
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- Dehydrogenation properties of ZnO and the impact of gold nanoparticles on the process
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The article presents the results of catalytic and surface properties of pure zinc oxide synthesized by hydrothermal method and surface-doped with gold nanoparticles. As a test reaction, the catalytic transformation of n-butyl alcohol towards the dehydrogenation or bimolecular condensation of symmetric ketone or an ester was studied. The tested materials catalyse both consecutive reactions, wherein the transformation towards the ketone is dependent on the presence of surface oxygen vacancies, whose concentration depends on the temperature. In turn, the transformation to the ester occurs in the presence of gold nanoparticles deposited on the surface of zinc oxide. The difference in work function of electrons from these materials create a change in the electron concentration in the surface area and will shift the balance of the coupling reaction of hydrogen with lattice oxygen, which prefers the formation of aldehyde and ester. The results were compared with the catalytic properties of other previously studied oxide systems in this group of changes. This analysis enabled the development of the mechanism of transformation and explanation of the impact of gold on the kinetics of the process.
- Suchorska-Wo?niak, Patrycja,Rac, Olga,Klimkiewicz, Roman,Fiedot, Marta,Teterycz, Helena
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p. 135 - 145
(2016/01/29)
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- Room-temperature catalytic oxidation of alcohols with the polyoxovanadate salt Cs5(V14As8O42Cl)
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While many known methods for oxidation mediated by polyoxometalates (POMs) employ environmentally friendly co-oxidants, they tend to employ large catalyst loadings (e.g. 40 mol%) and costly high reaction temperatures (~90-135 °C) that potentially contribute to the degradation of the catalyst and reduce their effectiveness. Herein, we present some initial results demonstrating a room temperature catalytic oxidation using the reduced salt-inclusion polyoxometalate, Cs5(V14As8O42Cl), that contains polyoxovanadate (POV) clusters as an efficient catalyst (e.g., 2 mol%) in the transformation of secondary alcohols to their corresponding ketones in very good to quantitative yields. Further, the catalyst can be suspended on celite and recycled.
- Campbell, McKenzie L.,Sulejmanovic, Dino,Schiller, Jacqueline B.,Turner, Emily M.,Hwu, Shiou-Jyh,Whitehead, Daniel C.
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p. 3208 - 3213
(2016/05/24)
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- Catalytic oxidation of alkanes by a (salen)osmium(VI) nitrido complex using H2O2 as the terminal oxidant
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The osmium(vi) nitrido complex, [OsVI(N)(L)(CH3OH)]+ (1, L = N,N′-bis(salicylidene)-o-cyclohexyldiamine dianion) is an efficient catalyst for the oxidation of alkanes under ambient conditions using H2O2 as the oxidant. Alkanes are oxidized to the corresponding alcohols and ketones, with yields up to 75% and turnover numbers up to 2230. Experimental and computational studies are consistent with a mechanism that involves O-atom transfer from H2O2 to [OsVI(N)(L)]+ to generate an [OsVIII(N)(O)(L)]+ active intermediate.
- Chen, Man,Pan, Yi,Kwong, Hoi-Ki,Zeng, Raymond J.,Lau, Kai-Chung,Lau, Tai-Chu
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supporting information
p. 13686 - 13689
(2015/09/02)
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- Acetone alkylation with ethanol over multifunctional catalysts by a borrowing hydrogen strategy
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Step by step alkylation of acetone (A) with ethanol (E) in a ratio of 1: 2 was investigated. A fixed bed flow-through reactor system was used at a total pressure of 21 bar and in the temperature range of 150-350 °C in inert He or a reducing H2 medium. Following the hydrogen borrowing methodology, two types of catalysts were prepared; using neutral activated carbon (AC) and alkaline hydrotalcite (HT) supports, namely 5 wt% Pd/AC in the presence of alkaline additives (10, 20 and 30 wt% KOH or 20% K3PO4); 9 wt% Cu/HT and 5 wt% Pd/HT. The catalysts were activated in a H2 flow at 350 °C. Different yields of mono- or dialkylated ketones were observed. In a hydrogen medium over the same catalyst systems the ketone products could be reduced to alcohols. In this study the Pd/HT catalyst seems to be the most promising for fuel production based on biomass fermentation.
- Onyestyák, Gy.,Novodárszki, Gy.,Barthos,Klébert, Sz.,Wellisch, á. Farkas,Pilbáth
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p. 99502 - 99509
(2015/12/04)
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- Unexpected dehomologation of primary alcohols to one-carbon shorter carboxylic acids using o-iodoxybenzoic acid (IBX)
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A novel and efficient transformation of primary alcohols to one-carbon shorter carboxylic acids using IBX is reported. Mechanistic studies revealed that the combination of IBX and molecular iodine produces a different active hypervalent iodine species.
- Xu, Shu,Itto, Kaori,Satoh, Masahide,Arimoto, Hirokazu
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supporting information
p. 2758 - 2761
(2014/03/21)
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- MONOMER, POLYMER, RESIST COMPOSITION, AND PATTERNING PROCESS
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A polymer comprising recurring units derived from a (meth)acrylate monomer of tertiary ester type having branched alkyl on alicycle is used to form a resist composition. When subjected to exposure, PEB and organic solvent development, the resist composition is improved in dissolution contrast.
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- The iron(II) complex [Fe(CF3SO3)2(mcp)] as a convenient, readily available catalyst for the selective oxidation of methylenic sites in alkanes
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The efficient and selective oxidation of secondary C-H sites of alkanes is achieved by using low catalyst loadings of a non-expensive, readily available iron catalyst [Fe(II)(CF3SO3)2(mcp)], {Fe-mcp, [mcp=N,N'-dimethyl-N,N'-bis(2-pyridylmethyl)cyclohexane-trans-1,2-diamine]}, and hydrogen peroxide (H2O2) as oxidant, via a simple reaction protocol. Natural products are selectively oxidized and isolated in synthetically amenable yields. The easy access to large quantities of the catalyst and the simplicity of the C-H oxidation procedure make this system a particularly convenient tool to carry out alkane C-H oxidation reactions on the preparative scale, and in short reaction times.
- Canta, Merce,Font, David,Gomez, Laura,Ribas, Xavi,Costas, Miquel
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supporting information
p. 818 - 830
(2014/04/03)
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- Regioselective ketone α-alkylation with simple olefins via dual activation
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Alkylation of carbonyl compounds is a commonly used carbon-carbon bond-forming reaction. However, the conventional enolate alkylation approach remains problematic due to lack of regioselectivity, risk of overalkylation, and the need for strongly basic conditions and expensive alkyl halide reagents. Here, we describe development of a ketone-alkylation strategy using simple olefins as the alkylating agents. This strategy employs a bifunctional catalyst comprising a secondary amine and a low-valent rhodium complex capable of activating ketones and olefins simultaneously. Both cyclic and acyclic ketones can be mono-a-alkylated with simple terminal olefins, such as ethylene, propylene, 1-hexene, and styrene, selectively at the less hindered site; a large number of functional groups are tolerated.The pH/redox neutral and byproduct-free nature of this dual-activation approach shows promise for large-scale syntheses.
- Mo, Fanyang,Dong, Guangbin
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- Activation of DMSO for Swern-type oxidation by 1,1-dichlorocycloheptatriene
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A new dimethylsulfoxide activation method employing 1,1-dichlorocycloheptatriene has been developed for a mild Swern-type oxidation of a variety of alcohols. The carbonyl products can be obtained in good to excellent yields from this operationally simple and efficient method. This work is the first report of dimethylsulfoxide activation by a simple chlorinated hydrocarbon reagent, which has the unique ability of equilibrating to its reactive aromatic cationic form.
- Nguyen, Thanh Vinh,Hall, Michael
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supporting information
p. 6895 - 6898
(2015/01/09)
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- Kinetics and mechanism of oxidation of aliphatic secondary alcohols by benzyltrimethylammonium chlorobromate
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Oxidation of several secondary alcohols by benzyltrimethylammonium chlorobromate (BTMACB) in aqueous acetic acid leads to the formation of corresponding ketones. The reaction is first order with respect to BTMACB and the alcohols. The reaction failed to induce the polymerization of acrylonitrile. There is no effect of tetrabutylammonium chloride on the reaction rate. The proposed reactive oxidizing species is chlorobromate ion. The oxidation of benzhydrol-α-d (PhCDOHPh) exhibited a substantial primary kinetic isotope effect (kH/kD = 5.61 at 298 K). The effect of solvent composition indicated that the rate increases with an increase in the polarity of the solvent. The reaction is susceptible to both the polar and steric effects of the substituents. A mechanism involving transfer of a hydride ion in the ratedetermining step has been proposed.
- Sharma, Pradeep K.
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p. 2702 - 2706
(2014/06/09)
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- Thiol-functionalized fructose-derived nanoporous carbon as a support for gold nanoparticles and its application for aerobic oxidation of alcohols in water
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Gold nanoparticles supported on thiol-functionalized fructose-derived nanoporous carbon (AuNPs@thiol-Fru-d-NPS) were found to be a simple bench-top, biocompatible, recyclable and selective catalytic system for the aerobic oxidation of various types of alcohols into their corresponding aldehydes and ketones at room temperature under the environmentally friendly conditions with excellent yields. Copyright
- Mahyari, Mojtaba,Shaabani, Ahmad,Behbahani, Mohammad,Bagheri, Akbar
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p. 576 - 583
(2014/08/05)
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- Copper-catalyzed aerobic oxidative functionalization of C-H bonds of alkanes in the presence of acetaldehyde under mild conditions
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Copper-catalyzed oxidative functionalization of C-H bonds of alkanes with molecular oxygen has been performed in the presence of Cu(OAc)2 catalyst and acetaldehyde in acetonitrile at 70 C with extremely high turn-over numbers.
- Hayashi, Yukiko,Komiya, Naruyoshi,Suzuki, Ken,Murahashi, Shun-Ichi
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p. 2706 - 2709
(2013/06/26)
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- SYNTHESIS OF HIGH CALORIC FUELS AND CHEMICALS
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In one embodiment, the present application discloses methods to selectively synthesize higher alcohols and hydrocarbons useful as fuels and industrial chemicals from syngas and biomass. Ketene and ketonization chemistry along with hydrogenation reactions are used to synthesize fuels and chemicals. In another embodiment, ketene used to form fuels and chemicals may be manufactured from acetic acid which in turn can be synthesized from synthesis gas which is produced from coal, biomass, natural gas, etc.
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Paragraph 00100
(2013/05/23)
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- Mono, di and trifunctional cyclic organic peroxides: The effect of substituents and ring size on their thermolysis in 1,4-dioxan
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The thermal decomposition reaction of cyclic organic peroxides was studied in 1,4-dioxan at initial concentrations between ～10-4 and 10-2molL-1 and at a temperature interval between 100 and 170°C, according to the thermal stability of each compound. The kinetic behaviour observed in all systems studied follows a pseudo first order kinetic law up to at least ～86% of peroxide conversion. An important substituent effect is operative on the rate constant values and consequently on the activation parameters of the thermal decomposition reaction. The application of different treatments (compensation affect or a statistical treatment) on the kinetic data shows the existence of two sets of cyclic peroxides with comparable kinetic behaviour. Different peroxide-solvent interaction mechanisms can be considered within each series.
- Nesprias, Rosa,Eyler, Gladys,Canizo, Adriana
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p. 1080 - 1087
(2013/09/24)
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- Regioselective oxidation of nonactivated alkyl C-H groups using highly structured non-heme iron catalysts
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Selective oxidation of alkyl C-H groups constitutes one of the highest challenges in organic synthesis. In this work, we show that mononuclear iron coordination complexes Λ-[Fe(CF3SO3) 2((S,S,R)-MCPP)] (Λ-1P), Δ-[Fe(CF3SO 3)2((R,R,R)-MCPP)] (Δ-1P), Λ-[Fe(CF 3SO3)2((S,S,R)-BPBPP)] (Λ-2P), and Δ-[Fe(CF3SO3)2((R,R,R)-BPBPP)] (Δ-2P) catalyze the fast, efficient, and selective oxidation of nonactivated alkyl C-H groups employing H2O2 as terminal oxidant. These complexes are based on tetradentate N-based ligands and contain iron centers embedded in highly structured coordination sites defined by two bulky 4,5-pinenopyridine donor ligands, a chiral diamine ligand backbone, and chirality at the metal (Λ or Δ). X-ray diffraction analysis shows that in Λ-1P and Λ-2P the pinene rings create cavity-like structures that isolate the iron site. The efficiency and regioselectivity in catalytic C-H oxidation reactions of these structurally rich complexes has been compared with those of Λ-[Fe(CF3SO3) 2((S,S)-MCP)] (Λ-1), Λ-[Fe(CF3SO 3)2((S,S)-BPBP)] (Λ-2), Δ-[Fe(CF 3SO3)2((R,R)-BPBP)] (Δ-2), Λ-[Fe(CH3CN)2((S,S)-BPBP)](SbF6) 2 (Λ-2SbF6), and Δ-[Fe(CH3CN) 2((R,R)-BPBP)](SbF6)2 (Δ-2SbF 6), which lack the steric bulk introduced by the pinene rings. Cavity-containing complexes Λ-1P and Λ-2P exhibit enhanced activity in comparison with Δ-1P, Δ-2P, Λ-1, Λ-2, and Λ-2SbF6. The regioselectivity exhibited by catalysts Λ-1P, Λ-2P, Δ-1P, and Δ-2P in the C-H oxidation of simple organic molecules can be predicted on the basis of the innate properties of the distinct C-H groups of the substrate. However, in specific complex organic molecules where oxidation of multiple C-H sites is competitive, the highly elaborate structure of the catalysts allows modulation of C-H regioselectivity between the oxidation of tertiary and secondary C-H groups and also among multiple methylene sites, providing oxidation products in synthetically valuable yields. These selectivities complement those accomplished with structurally simpler oxidants, including non-heme iron catalysts Λ-2 and Λ-2SbF6.
- Gómez, Laura,Canta, Merceì,Font, David,Prat, Irene,Ribas, Xavi,Costas, Miquel
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p. 1421 - 1433
(2013/03/29)
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- METHOD TO CONVERT FERMENTATION MIXTURE INTO FUELS
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The present disclosure provides methods to produce ketones suitable for use as fuels and lubricants by catalytic conversion of an acetone-butanol-ethanol (ABE) fermentation product mixture that can be derived from biomass.
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Page/Page column 73-74
(2013/02/27)
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- Vapor-phase ketonization of aliphatic acids on a chromite catalyst
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The catalytic conversion of acetic, propionic, and butyric acid in the presence of water vapor on oxide chromium-zinc-manganese catalyst promoted by potassium carbonate in the temperature range 300- 400°C was studied. The main products of the acids conversion were found to be symmetrical ketones, water, and carbon dioxide. The optimum yield of ketones is achieved at 325°C. The yields were as follows: up to 96 mol % of acetone, 95 mol % of diethyl ketone, and 92 mol % of dipropyl ketone. A side reaction is the decarboxylation of acids, the contribution of which increases with increasing temperature. Under these conditions a clevage of molecules with the formation of lower ketones, hydrogen, methane, and carbon monoxide. Yield of symmetrical ketones from aliphatic acids is much higher than from the corresponding aldehydes and alcohols, and the maximum yield is obtained at a lower temperature. By the example of ketonization of the acetic acid it was found that the reaction proceeds quite successfully at reducing the water concentration in the reaction mixture. This enabled us to improve the performance of the process of ketones production. Pleiades Publishing, Ltd., 2011.
- Stonkus,Yuskovets,Leite,Fleisher,Edolfa,Liepina,Mishnev,Shmidlers
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scheme or table
p. 1523 - 1528
(2011/10/18)
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- Structure-reactivity relationship for alcohol oxidations via hydride transfer to a carbocationic oxidizing agent
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Second-order rate constants were determined for the oxidation of 27 alcohols (R1R2CHOH) by a carbocationic oxidizing agent, 9-phenylxanthylium ion, in acetontrile at 60°C. Alcohols include open-chain alkyl, cycloalkyl, and unsaturated alcohols. Kinetic isotope effects for the reaction of 1-phenylethanol were determined at three H/D positions of the alcohol (KIEα-D=3.9, KIEβ-D3=1.03, KIE OD=1.10). These KIE results are consistent with those we previously reported for the 2-propanol reaction, suggesting that these reactions follow a hydride-proton sequential transfer mechanism that involves a rate-limiting formation of the α-hydroxy carbocation intermediate. Structure-reactivity relationship for alcohol oxidations was deeply discussed on the basis of the observed structural effects on the formation of the carbocationic transition state (Cδ+-OH). Efficiencies of alcohol oxidations are largely dependent upon the alcohol structures. Steric hindrance effect and ring strain relief effect win over the electronic effect in determining the rates of the oxidations of open-chain alkyl and cycloalkyl alcohols. Unhindered secondary alkyl alcohols would be selectively oxidized in the presence of primary and hindered secondary alkyl alcohols. Strained C7-C11 cycloalkyl alcohols react faster than cyclohexyl alcohol, whereas the strained C5 and C12 alcohols react slower. Aromatic alcohols would be efficiently and selectively oxidized in the presence of aliphatic alcohols of comparable steric requirements. This structure-reactivity relationship for alcohol oxidations via hydride-transfer mechanism is hoped to provide a useful guidance for the selective oxidation of certain alcohol functional groups in organic synthesis. Copyright
- Lu, Yun,Bradshaw, Joshua,Zhao, Yu,Kuester, William,Kabotso, Daniel
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p. 1172 - 1178
(2013/01/12)
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- Conversion of biomass-derived butanal into gasoline-range branched hydrocarbon over Pd-supported catalysts
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For production of gasoline-range branched hydrocarbon from butanal, Pd catalysts supported on different metal oxides were applied. Among the prepared catalysts, Pd/ZrO2 showed the complete butanal conversion with the formation of C7-to-C9 branched hydrocarbon (75% yield). Additionally, the ratios of O/C and straight-chain to branched hydrocarbon (n-C/br-C) were found to be 0.005 and 0.17, respectively. This indicates that an adequate combination of Pd dispersion and amphoteric ZrO2 character promoted hydrodeoxygenation, C-C coupling and isomerization reactions. Consequently, both Pd dispersion and acid-base properties of supports are suggested to play a pivotal role in producing gasoline-range hydrocarbon at a high yield.
- Kim, Sung Min,Lee, Mi Eun,Choi, Jae-Wook,Suh, Dong Jin,Suh, Young-Woong
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scheme or table
p. 108 - 113
(2012/03/10)
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- Mild homogeneous oxidation of alkanes and alcohols including glycerol with tert-butyl hydroperoxide catalyzed by a tetracopper(II) complex
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The homogeneous catalytic system composed of the aqua-soluble tetracopper(II) triethanolaminate complex [O?Cu4{N(CH2CH2O)3}4(BOH)4][BF4]2 (1), t-BuOOH (TBHP), water and acetonitrile solvent (optional) has been applied for the mild oxidation of (i) linear and cyclic alkanes to the corresponding alkyl peroxides, alcohols and ketones, (ii) secondary or primary alcohols to ketones or aldehydes, respectively and (iii) glycerol (GLY) to dihydroxyacetone (DHA). Unusual regio-, bond and stereoselectivity parameters have been determined for the alkane oxygenations and discussed in terms of possible steric, hydrophobic and electronic effects. In alcohol oxidations, secondary alcohols are the most reactive substrates. Yields and TONs up to 82% and 1200, respectively, have been obtained in the oxidation of isopropanol to acetone. The selective oxidation of GLY to DHA by the 1/TBHP system has been also achieved, although providing lower conversions. The 1/H2O2 system for the GLY oxidation is particularly advantageous in terms of selectivity and oxidant efficiency. These systems constitute one of the first examples of a metal-catalyzed oxidation of glycerol under homogeneous conditions.
- Kirillova, Marina V.,Kirillov, Alexander M.,Mandelli, Dalmo,Carvalho, Wagner A.,Pombeiro, Armando J.L.,Shul'Pin, Georgiy B.
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scheme or table
p. 9 - 17
(2010/09/09)
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- Thermal decomposition of cyclic organic peroxides in pure solvents and binary solvent mixtures
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The thermal decomposition reaction of acetone cyclic triperoxide, acetone cyclic diperoxide, 4-heptanone cyclic diperoxide, and pinacolone cyclic diperoxide ca. 0.02 M was studied in pure solvents (acetone and 1 -propanol) and in binary mixtures of acetone/1-propanol at 150°C. The kinetics of each system was explored by gas chromatography (GC) at different solvent compositions. The reactions showed a behavior accordingly with a pseudo-first-order kinetic law up to at least 90% peroxide decomposition. The main organic products derived from these thermolysis reactions were detected by GC analysis. Among them, the corresponding ketones, methane, ethane, and propane were the main identified products. The rates of decomposition of pinacolone diperoxide in the pure solvents were practically independent of the solvent characteristics, so it was of no interest to analyze its kinetic behavior in binary solvent mixtures. In acetone/1-propanol mixtures, the solvation effect on the cyclic peroxides derived from 4-heptanone and acetone molecules was slightly dominated by specific interactions between 1-propanol and a diradical-activated complex initially formed. This species was preferentially solvated by 1-propanol instead of acetone. Specific interactions between the O atoms from the peroxidic bond and the H from the OH in 1-propanol can be taken into account.
- Iglesias, Mariangeles,Barreto, GastoN P.,Eyler, Gladys N.,Canizo, Adriana I.
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experimental part
p. 347 - 353
(2011/07/29)
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- Catalytic conversion of C12-C14 primary alcohols mixture into long-chain ketones
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A charge of raw primary alcohols of high molecular weight from commercial plant was transformed into long-chain ketones fraction of potential commercial use. In this continuous flow method LaMnO3/La-Al2O 3 catalyst was used. At 420 °C and a normal pressure mixture of 74.2 wt.% C12 and 25.8 wt.% C14 primary alcohols and toluene (weight ratio alcohols:toluene = 1:1) was converted into ketones with 73.4% yield in relation to the theoretical value. Ketones were analyzed by TLC, NMR and GC-MSD.
- Klimkiewicz, Roman,Morawski, Ireneusz,Trawczyński, Janusz
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scheme or table
p. 1143 - 1147
(2010/11/16)
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- Continuous heterogeneous catalytic oxidation of primary and secondary alcohols in scCO2
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A miniature catalytic reactor has been developed for the oxidation of alcohols with O2 in supercritical CO2. Particular attention has been given to ensuring good mixing of O2 and CO 2 prior to contact with the substrate. The reactor was optimised using the oxidation of 2-octanol over 5% Pt + 1% Bi on Al2O 3 and the mass balance was measured. The reactor was then evaluated for the oxidation of a series of secondary alcohols, and also the primary alcohol, 1-octanol.
- Chapman, Adrian O.,Akien, Geoffrey R.,Arrowsmith, Nicholas J.,Licence, Peter,Poliakoff, Martyn
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experimental part
p. 310 - 315
(2011/03/18)
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- Alkane oxidation by the H2O2-NaVO3-H2SO4 system in acetonitrile and water
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A simple system is described, which oxidizes saturated hydrocarbons either in acetonitrile or (less efficiently) in water. The system consists of 50% aqueous hydrogen peroxide as an oxidant, sodium metavanadate, NaVO3, as a catalyst and sulfuric (or oxalic) acid as a co-catalyst. The reactions were carried out at 20-50 °C. In the oxidation of cyclohexane in acetonitrile, the highest yield (37% based on cyclohexane) and turnover number (TON=1700) were attained after 3 h at 50 °C. The corresponding parameters were 16% and 1090 for n-heptane oxidation under the same conditions. The oxidation of higher alkanes, RH, in acetonitrile gives almost exclusively the corresponding alkyl hydroperoxides, ROOH. Light alkanes (n-butane, propane, ethane, and methane) have been also oxygenated by the system under consideration. The highest TON (200) was attained for ethane and the highest yield (19%) was obtained in the case of n-butane. The selectivity parameters measured for the oxidation of linear and branched alkanes are low, the reaction with cis- and trans-1,2-dimethylcyclohexanes is not stereoselective. These facts lead us to conclude that the oxidation occurs with the formation of hydroxyl radicals in the crucial step.
- Shul'pina, Lidia S.,Kirillova, Marina V.,Pombeiro, Armando J.L.,Shul'pin, Georgiy B.
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experimental part
p. 2424 - 2429
(2009/07/25)
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- Reusable gold(I) catalysts with unique regioselectivity for intermolecular hydroamination of alkynes
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Two gold(I) phosphine complexes bearing the low-coordinating bis(trifluoromethanesulfonyl)- imidate ligand, namely AuSPhosNTf2 and AuPPh3NTf2, are active catalysts for the regioselective intermolecular hydroamination of both internal and terminal alkynes under mild reaction conditions. The catalysts show a regioselectivity based on electronic rather than steric factors, which allow the preferential synthesis of regioisomers opposite to those described previously. This subtle chemo- and regiose-lectivity depends on the catalyst, substrates and reaction conditions employed, and allows one to perform new tandem reactions. These gold(I) complexes operate under free-solvent conditions, without exclusion of air, without addition of acidic promoters and can be quantitatively recovered and reused by simple precipitation in hexane.
- Leyva, Antonio,Corma, Avelino
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supporting information; experimental part
p. 2876 - 2886
(2010/03/25)
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- An efficient protocol for the oxidative hydrolysis of ketone SAMP hydrazones employing SeO2 and H2O2 under buffered (pH 7) conditions
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An effective oxidative protocol for the liberation of ketones from SAMP hydrazones employing peroxyselenous acid under aqueous buffered conditions (pH 7) has been developed. The procedure proceeds without epimerization of adjacent stereocenters or dehydration, in representative SAMP alkylation and aldol reaction adducts, respectively.
- Smith III, Amos B.,Liu, Zhuqing,Simov, Vladimir
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experimental part
p. 3131 - 3134
(2010/03/24)
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- Efficient catalytic oxidation of alkanes by lewis acid/[Os VI(N)Cl4]- using peroxides as terminal oxidants. Evidence for a metal-based active intermediate
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The oxidation of alkanes by various peroxides (tBuOOH, H 2O2, PhCH2C(CH3)2OOH) is efficiently catalyzed by [OsVI(N)Cl4]-/Lewis acid (FeCl3 or Sc(OTf)3) in CH2Cl 2/CH3CO2H to give alcohols and ketones. Oxidations occur rapidly at ambient conditions, and excellent yields and turnover numbers of over 7500 and 1000 can be achieved in the oxidation of cyclohexane with tBuOOH and H2O2, respectively. In particular, this catalytic system can utilize PhCH2C(CH 3)2OOH (MPPH) efficiently as the terminal oxidant; good yields of cyclohexanol and cyclohexanone (>70%) and MPPOH (>90%) are obtained in the oxidation of cyclohexane. This suggests that the mechanism does not involve alkoxy radicals derived from homolytic cleavage of MPPH but is consistent with heterolytic cleavage of MPPH to produce a metal-based active intermediate. The following evidence also shows that no free alkyl radicals are produced in the catalytic oxidation of alkanes: (1) The product yields and distributions are only slightly affected by the presence of O2. (2) Addition of BrCCl3 does not affect the yields of cyclohexanol and cyclohexanone in the oxidation of cyclohexane. (3) A complete retention of stereochemistry occurs in the hydroxylation of cis- and trans-1,2- dimethylcyclohexane. The proposed mechanism involves initial O-atom transfer from ROOH to [OsVI(N)Cl4]-/Lewis acid to generate [OsVIII(N)(O)Cl4]-/Lewis acid, which then oxidizes alkanes via H-atom abstraction.
- Yiu, Shek-Man,Man, Wai-Lun,Lau, Tai-Chu
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scheme or table
p. 10821 - 10827
(2009/02/05)
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- PRODUCTION OF GASOLINE FROM FERMENTABLE FEEDSTOCKS
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Methods are disclosed for forming heptan-4-one, and, optionally, heptan-4-ol, from fermentable sugars. The sugars are fermented using a bacteria or yeast that predominantly forms butyric acid. The butyric acid is subjected to catalytic ketonization conditions to form heptan-4-one, with concomitant loss of water and carbon dioxide. The heptan-4-one can be subjected to catalytic hydrogenation to form heptan-4-ol, an either of these can be included in gasoline compositions. In one aspect, the fermentable sugars are derived from lignocellulosic materials such as wood products, switchgrass, or agricultural wastes, which are delignified to form lignin, cellulose and hemicellulose. The cellulose and hemicellulose can be depolymerized to form glycose and xylose, either or both of which can be fermented by the bacteria. Thus, the methods described herein can convert biomass to a fuel composition or fuel additive, which can be used in a conventional gasoline engine, unlike traditional fuels such as ethanol or biodiesel.
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Page/Page column 11
(2009/01/23)
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- Oxidation of alcohols by chlorine dioxide in organic solvents
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The kinetics of oxidation of a series of alcohols (propan-2-ol, 2-methylpropan-1-ol, butan-1-ol, butan-2-ol, 3-methylpentan-1-ol, heptan-4-ol, decan-2-ol, cyclohexanol, borneol) by chlorine dioxide in organic solvents was studied using spectrophotometry. The reaction is described by the second-order rate equation w = k[ROH][ClO2]. The rate constants were measured in the range of 10-60 °C, and the activation parameters of the processes were calculated. The products were identified, and the yields were determined.
- Ganieva,Ganiev,Grabovskiy,Kabalnova
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body text
p. 2328 - 2331
(2010/02/15)
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- Catalytic deprotection of acetals in basic solution with a self-assembled supramolecular "nanozyme"
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(Formula Presented) Changing on the inside: Acetals are a commonly used protecting groups for aldehydes and ketones in organic synthesis because of their ease of installation and resistance to cleavage in neutral or basic solution. A self-assembled supramolecular assembly has been shown to catalyze the hydrolysis of acetals and ketals in basic solution (see scheme).
- Pluth, Michael D.,Bergman, Robert G.,Raymond, Kenneth N.
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p. 8587 - 8589
(2008/09/18)
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