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Cas Database

67-64-1

67-64-1

Identification

  • Product Name:Acetone

  • CAS Number: 67-64-1

  • EINECS:200-662-2

  • Molecular Weight:58.08

  • Molecular Formula: C3H6O

  • HS Code:2914.11 Oral rat LD50: 5800 mg/kg

  • Mol File:67-64-1.mol

Synonyms:Dimethyl ketone;Dimethylformaldehyde;NSC 135802;Propanone;Pyroacetic ether;beta-Ketopropane;Acetone(8CI);Methyl ketone (6CI);2-Propanone;

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Safety information and MSDS view more

  • Pictogram(s):FlammableF,IrritantXi

  • Hazard Codes: F:Flammable;

  • Signal Word:Danger

  • Hazard Statement:H225 Highly flammable liquid and vapourH319 Causes serious eye irritation H336 May cause drowsiness or dizziness

  • First-aid measures: General adviceConsult a physician. Show this safety data sheet to the doctor in attendance.If inhaled Fresh air, rest. Refer for medical attention. In case of skin contact Remove contaminated clothes. Rinse skin with plenty of water or shower. In case of eye contact Rinse with plenty of water (remove contact lenses if easily possible). Refer for medical attention. If swallowed Rinse mouth. Refer for medical attention . INHALATION: vapor irritating to eyes and mucous membranes; acts as an anesthetic in very high concentrations. INGESTION: low order of toxicity but very irritating to mucous membranes. SKIN: prolonged excessive contact causes defatting of the skin, possibly leading to dermatitis. (USCG, 1999) Immediate first aid: Ensure that adequate decontamination has been carried out. If patient is not breathing, start artificial respiration, preferably with a demand-valve resuscitator, bag-valve-mask device, or pocket mask, as trained. Perform CPR as necessary. Immediately flush contaminated eyes with gently flowing water. Do not induce vomiting. If vomiting occurs, lean patient forward or place on left side (head-down position, if possible) to maintain an open airway and prevent aspiration. Keep patient quiet and maintain normal body temperature. Obtain medical attention. /Ketones and related compounds/

  • Fire-fighting measures: Suitable extinguishing media If material is on fire or involved in fire: Do not extinguish fire unless flow can be stopped. Use water in flooding quantities as fog. Solid streams of water may be ineffective. Cool all affected containers with flooding quantities of water. Apply water from as far a distance as possible. Use "alcohol" foam, carbon dioxide, or dry chemical. Excerpt from ERG Guide 127 [Flammable Liquids (Water-Miscible)]: HIGHLY FLAMMABLE: Will be easily ignited by heat, sparks or flames. Vapors may form explosive mixtures with air. Vapors may travel to source of ignition and flash back. Most vapors are heavier than air. They will spread along ground and collect in low or confined areas (sewers, basements, tanks). Vapor explosion hazard indoors, outdoors or in sewers. Those substances designated with a (P) may polymerize explosively when heated or involved in a fire. Runoff to sewer may create fire or explosion hazard. Containers may explode when heated. Many liquids are lighter than water. (ERG, 2016) Wear self-contained breathing apparatus for firefighting if necessary.

  • Accidental release measures: Use personal protective equipment. Avoid dust formation. Avoid breathing vapours, mist or gas. Ensure adequate ventilation. Evacuate personnel to safe areas. Avoid breathing dust. For personal protection see section 8. Remove all ignition sources. Personal protection: filter respirator for organic gases and vapours of low boiling point adapted to the airborne concentration of the substance. Ventilation. Collect leaking liquid in sealable containers. Absorb remaining liquid in sand or inert absorbent. Then store and dispose of according to local regulations. Do NOT wash away into sewer. Accidental release measures. Personal precautions, protective equipment and emergency procedures: Use personal protective equipment. Avoid breathing vapors, mist or gas. Ensure adequate ventilation. Remove all sources of ignition. Evacuate personnel to safe areas. Beware of vapors accumulating to form explosive concentrations. Vapors can accumulate in low areas.; Environmental precautions: Prevent further leakage or spillage if safe to do so. Do not let product enter drains.; Methods and materials for containment and cleaning up: Contain spillage, and then collect with an electrically protected vacuum cleaner or by wet-brushing and place in container for disposal according to local regulations.

  • Handling and storage: Avoid contact with skin and eyes. Avoid formation of dust and aerosols. Avoid exposure - obtain special instructions before use.Provide appropriate exhaust ventilation at places where dust is formed. For precautions see section 2.2. Fireproof. Separated from : see Chemical Dangers. Store in an area without drain or sewer access.Conditions for safe storage, including any incompatibilities: Keep container tightly closed in a dry and well-ventilated place. Containers which are opened must be carefully resealed and kept upright to prevent leakage. Storage class (TRGS 510): Flammable liquids

  • Exposure controls/personal protection:Occupational Exposure limit valuesRecommended Exposure Limit: 10-hour Time-Weighted Average: 250 ppm (590 mg/cu m).Biological limit values Handle in accordance with good industrial hygiene and safety practice. Wash hands before breaks and at the end of workday. Eye/face protection Safety glasses with side-shields conforming to EN166. Use equipment for eye protection tested and approved under appropriate government standards such as NIOSH (US) or EN 166(EU). Skin protection Wear impervious clothing. The type of protective equipment must be selected according to the concentration and amount of the dangerous substance at the specific workplace. Handle with gloves. Gloves must be inspected prior to use. Use proper glove removal technique(without touching glove's outer surface) to avoid skin contact with this product. Dispose of contaminated gloves after use in accordance with applicable laws and good laboratory practices. Wash and dry hands. The selected protective gloves have to satisfy the specifications of EU Directive 89/686/EEC and the standard EN 374 derived from it. Respiratory protection Wear dust mask when handling large quantities. Thermal hazards

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Relevant articles and documentsAll total 1764 Articles be found

Atomically precise silver clusters for efficient chlorocarbon degradation

Bootharaju,Deepesh,Udayabhaskararao,Pradeep

, p. 611 - 620 (2013)

We describe the degradation of chlorocarbons (CCl4, C 6H5CH2Cl and CHCl3) in solution at room temperature (27 ± 4 °C) by the monolayer-protected silver quantum cluster, Ag9MSA7 (MSA: mercaptosuccinic acid) in the presence of isopropyl alcohol (IPA). The main degradation products were silver chloride and amorphous carbon. Benzyl chloride was less reactive towards clusters than CCl4 and CHCl3. Materials used in the reactions and the reaction products were characterized using several spectroscopic and microscopic tools such as ultraviolet-visible (UV/Vis) absorption spectroscopy, Fourier transform infrared spectroscopy (FTIR), photoluminescence spectroscopy, X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), energy dispersive analysis of X-rays (EDAX) and scanning electron microscopy (SEM). We have shown that clusters are more efficient for the degradation of halocarbons than the corresponding monolayer-protected nanoparticles (Ag@MSA, particle diameter 15 ± 5 nm) at a given time and temperature. The higher reactivity of clusters is attributed to their small size and large surface area. Clusters and nanoparticles were used for reactions in supported (on neutral alumina) and unsupported forms. A possible mechanism for the reaction has been postulated on the basis of experimental results.

EVIDENCE SUPPORTING A SINGLE ELECTRON TRANSFER PATHWAY IN THE REDUCTION OF AROMATIC KETONES BY METAL ALKOXIDES. LITHIUM ISOPROPOXIDE, AN EXCELLENT REDUCING AGENT FOR AROMATIC KETONES.

Ashby, E. C.,Goel, Anil B.,Argyropoulos, John N.

, p. 2273 - 2276 (1982)

Reactions of various metal alkoxides with aromatic ketones have been shown to produce radical intermediates.Lithium isopropoxide has been found to be an excellent reducing agent for aromatic ketones and reduces benzophenone at a faster rate than does aluminum isopropoxide.

Transfer hydrogenation with abnormal dicarbene rhodium(iii) complexes containing ancillary and modular poly-pyridine ligands

Farrell, Kevin,Melle, Philipp,Gossage, Robert A.,Müller-Bunz, Helge,Albrecht, Martin

, p. 4570 - 4579 (2016)

Treatment of an abnormal dicarbene ligated rhodium(iii) dimer with 2,2′-bipyridine (bipy), 1,10-phenanthroline (phen) or 2,2′:6′,2′′-terpyridine (terpy) results in coordination of the N-donor ligands and concomitant cleavage of the dimeric structure. Depending on the denticity of the pyridyl ligand, this situation retains one (L = terpy) or two (L = bipy, phen) flexible sites for substrate coordination. In the case of the bipy complexes, modification of the electron density at Rh, without directly affecting the steric environment about the metal centre, was achieved by the incorporation of electron-donating or electron-withdrawing substituents on the bipy backbone. The dicarbene pyridyl complexes were active in transfer hydrogenation catalysis of benzophenone at 0.15 mol% catalyst loading in a iPrOH/KOH mixture. The catalysts displayed a strong characteristic colour change (yellow to purple) after activation which allowed for visual monitoring of the status of the reaction. The colour probe and the robustness of the active catalysts proved useful for catalyst recycling. The catalytic activity sustained over five consecutive substrate batch additions and gave a maximum overall turnover number of 3100.

Energy-storing Photocatalysis of Transition Metal Complexes with High Quantum Efficiency

Yamakawa, Tetsu,Miyake, Hiroto,Moriyama, Hiroshi,Shinoda, Sumio,Saito, Yasukazu

, p. 326 - 327 (1986)

A tin(II)-co-ordinated iridium complex catalyst exhibited the highest photoreactivity ever reported for the energy-storing reaction of propan-2-ol dehydrogenation, with quantum efficiency and even 'photo-thermal energy conversion efficiency' exceeding unity.

Conversion of ethanol over supported cobalt oxide catalysts

Rybak,Tomaszewska,MacHocki,Grzegorczyk,Denis

, p. 14 - 20 (2011)

Conversion of ethanol was investigated on supported (ceria, zirconia and ceria-zirconia) cobalt oxide catalysts. The catalysts were prepared by support impregnation with cobalt nitrate-citric acid solution and they were explored by comparing results from different characterization techniques: X-ray fluorescence, X-ray diffraction, Raman spectroscopy and nitrogen adsorption techniques. Their catalytic properties at 693 K were characterized in a fixed-bed reactor. The CoOx/CeO2 catalyst displayed the highest catalytic activity. The conversion of ethanol decreased with the increase of the ZrO2/CeO2 ratio in the support of catalyst. All catalysts exhibited high selectivity of ethanol conversion to hydrogen and acetone. The coking of catalysts under reaction conditions was also characterized by gravimetric method. The results indicated that the increase of the ZrO2/CeO2 ratio in the support exerts significant influence on the coke formation. The amount of carbon deposited on CoO x/ZrO2 at 693 K was higher than on any other catalyst. Raman studies of used catalysts proved that their surface was almost completely covered with carbonaceous deposit, which was probably the main reason of deactivation of catalysts under reaction conditions.

Catalytic effect of cuprous ions on the thermal decomposition of 3,3,6,6-tetramethyl-1,2,4,5-tetraoxane in methanol solution

Gimenez,Romero,Bustillo,Jorge,Gomez Vara,Castro

, p. 1273 - 1276 (2008)

Thermal decomposition of 3,3,6,6-tetramethyl-1,2,4,5-tetraoxane was examined in methanol solution (1.69×10-2 M) containing cuprous ions (5.05×10-7 M) in the temperature range from 130 to 166°C using UV spectroscopy as analytical method. The ion-catalyzed reaction follows first-order kinetics with respect to the peroxide and added cuprous ions. The temperature effect on the rate of thermal decomposition of the title compound was described by the corresponding Arrhenius equations, and its stability in solution was estimated on a quantitative level. The activation parameters of the initial step of decomposition of 3,3,6,6-tetramethyl-1,2,4,5- tetraoxane were determined (ΔH≠ = 14.7±0.8 kcal mol-1; ΔS≠ = -38.9±1.4 cal mol -1 K-1; ΔG ≠ = 31.0±0.8 kcal mol-1). Electron-transfer mechanism was proposed for the reaction under study.

Rate constant for the reaction of CH3C(O)CH2 radical with HBr and its thermochemical implication

Farkas, Edit,Kovacs, Gergely,Szilagyi, Istvan,Dobe, Sandor,Berces, Tibor,Marta, Ferenc

, p. 32 - 37 (2006)

The fast flow method with laser induced fluorescence detection of CH 3C(O)CH2 was employed to obtain the rate constant of k1 (298 K) = (1.83 ± 0.12 (1σ)) × 1010 cm3 mol-1 s-1 for the reaction CH 3C(O)CH2 + HBr ? CH3C(O)CH3 + Br (1, -1). The observed reduced reactivity compared with n-alkyl or alkoxyl radicals can be attributed to the partial resonance stabilization of the acetonyl radical. An application of k1 in a third law estimation provides Δf H298O (CH 3C(O)CH2) values of -24 kJ mol-1 and -28 kJ mol-1 depending on the rate constants available for reaction (- 1) from the literature.

Comparison N-CU–codoped nanotitania and n-doped nanotitania in photocatalytic reduction of CO2under UV light

Liu, Cuiping,Yua, Tao,Tan, Xin,Huang, Xiang

, p. 9 - 14 (2017)

Nitrogen-copper–codoped nanotitania and nitrogen-doped nanotitania for CO2 photoreduction by water in liquid phase were prepared by sol-gel method. The catalysts were characterized by XRD, HRTEM, DRS, FTIR, and XPS. N-doped TiO2 have remarkably better photocatalytic activity than N- and Cu-codoped TiO2 for the CO2 photoreduction to acetone under ultraviolet illumination. The acetone yield of N3/TiO2 could reach 52.6 μmol/g h and the acetone yield of Cu0.6N4/TiO2 could reach 33.2 μmol/g h under UV conditions. The mechanism of CO2photoreduction on N-doped nanotitania and N-Cu–codoped TiO2was proposed.

CHANGE IN THE RATE OF DECOMPOSITION OF DIOXETANES IN SULFOLANE SOLUTIONS IN THE TRANSITION FROM THE LIQUID TO THE SOLID PHASE

Sharipov, G. L.,Ostakhov, S. S.,Voloshin, A. I.,Lotnik, S. V.,Kazakov, V. P.,Tolstikov, G. A.

, p. 2012 - 2016 (1988)

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A Thermokinetic Foundation for Oscillatory Phenomena in Gaseous Organic Oxidations under Well Stirred Flowing Conditions

Griffiths, John F.,Hasko, Stephen M.,Shaw, Nigel K.,Torrez-Mujica, Tomas

, p. 343 - 354 (1985)

An experimental and theoretical attack on the fundamentals of thermokinetic phenomena associated with the gaseous, non-isothermal oxidation of hydrocarbons and other organic substrates is described.Quantitative comparisons are made between numerical modelling and experimental measurements under well stirred flowing conditions.Two chemical systems are considered, involving reactions of methyl radicals.These are: (i) di-t-butyl peroxide decomposition in nitrogen and (ii) di-t-butyl peroxide decomposition in an excess of oxygen.Simplified kinetic mechanisms for each of these systems are described and numerical computations for non-isothermal reactions are discussed.Stationary states and two different types of oscillatory modes are predicted to exist within limited ranges of p, Ta and composition, and these match experimental measurements quite satisfactorily.The integral role played by self heating in termokinetic oscillations is demonstrated and relationships to cool-flame phenomena are outlined.

-

Cooley

, (1938)

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Kinetics of the Oxidation of 2-Hydroxy-2-methylpropanoic Acid by Silver(II) Ions Complexed with 2,2'-Bipyridine in Aqueous Nitrate Media

Heyward, Malcolm P.,Wells, Cecil F.

, p. 1057 - 1070 (1985)

Stopped-flow traces show that the oxidation of 2-hydroxy-2-methylpropionic acid (hmpa) by 2+ proceeds in two consecutive reactions.Both are found to be first order in II> and first order in .The first rapid reaction is ascribed to complex formation between AgII and hmpa and the second to a slower redox step.A mechanism is proposed to account for the observed orders in II>, and +> for each reaction and values for the enthalpies and entropies of activation are determined.To investigate the effect on the redox kinetics of oxidatively inert species close to the cation, these are compared with the transition-state parameters for the oxidation of hmpa by aqua-metal cations and for the oxidation of other substrates by metal cations complexed with 2,2'-bipyridine.

Ketonization of Acetophenone Enol in Aqueous Buffer Solutions. Rate-Equilibrium Relations and Mechanism of the "Uncatalyzed" Reaction

Chiang, Y.,Kresge, A. J.,Santaballa, J. A.,Wirz, J.

, p. 5506 - 5510 (1988)

Rates of ketonization of acetophenone enol, generated by photohydration of phenylacetylene and Norrish type II photoelimination of γ-hydroxybutyrophenone, were measured at 25 deg C in aqueous buffer solutions of six carboxylic acids, six phosphonic acid monoanions, phosphoric acid, and dihydrogen phosphate.Analysis of the carboxylic acid data produced catalytic coefficients from which linear Broensted correlations were constructed, with α = 0.50 for ketonization of the enol and α = 0.32 for the more rapid ketonization of the enolate ion.A more extended, curved Broensted correlation for ketonization of the enolate ion was constructed by combining the carboxylic acid results with catalytic coefficients for the phosphonic acid monoanions, and analysis of this by Marcus theory gave the intrinsic barrier ΔG0+ = 12 kcal mol-1 and the work terms wτ = 2 kcal mol-1 and wp = 4 kcal mol-1.These results differ from the much smaller intrinsic barrier and strongly disparate work terms obtained previously in a similar study of isobutyrophenone enol, and an explanation of the difference in terms of a looser transition state (Kreevoy τ = 0.30) for the isobutyrophenone system is offered.Evidence is also supplied which indicates that the so-called "uncatalyzed" ketonization reaction occurs by a stepwise route rather than by a cyclic single-step mechanism.

A Composite Ru-Pt Catalyst for 2-Propanol Dehydrogenation Adoptable to the Chemical Heat Pump System

Ito, Eri,Yamashita, Masaru,Hagiwara, Shigeji,Saito, Yasukazu

, p. 351 - 354 (1991)

Synergetic promotion was observed for 2-propanol dehydrogenation with a composite Ru-Pt/carbon catalyst prepared by NaBH4 reduction of mixed metal chlorides adsorbed on active carbon in an aqueous solution.Metal crystallites were less than 2 nm in size.The pronounced rate is promising as the catalyst for the heat pump system.

Gas-Phase Chemiluminescence Study of Chemically Activated Tetramethyl-1,2-dioxetane Formed from the Reaction of O2(1Δg) with 2,3-Dimethyl-2-butene

Bogan, Denis J.,Lee, Dong-Heon

, p. 9304 - 9310 (1992)

Chemically activated tetramethyl-1,2-dioxetane has been prepared by the reaction of O2(1Δg) with 2,3-dimethyl-2-butene at temperatures of 450 to 775 K and a pressure of 0.25 Torr.The observed product of the reaction was excited 1n?*(S1) acetone, which was identified by chemiluminescence spectra of the acetone (S1 -> S0) transition.Neither acetone (Ti) nor any other excited states were observed under the above conditions.The temperature dependence of the chemiluminescence gave an activation energy for the cycloaddition reaction of 8610 +/- 200 (1?) cal/mol.The quantum yield for acetone (S1) was 4 * 10-3 per reactive collision; its (1?) error is estimated as +/- a factor of 3.Chemiluminescence spectra taken at O2(3Σ1g) partial pressures greater than 2 Torr showed formaldehyde (S1 -> S0) bands.This is attributed to the well-known hydrocarbon "cool flame" mechanism, due to the presence of methyl radical formed by the thermal decomposition, in two steps, of 2,3-dimethyl-3-hydroperoxy-1-butene, another product path for the title reaction.This is the first report on the chemically activated decomposition of tetramethyl-1,2-dioxetane.

ZEOLITE-SUPPORTED TETRAMETHYL-1,2-DIOXETANE: NEW PATHWAYS TO CHEMILUMINESCENCE

Benedict, Bryan L.,Ellis, Arthur B.

, p. 1625 - 1634 (1987)

The thermal decomposition of tetramethyl-1,2-dioxetane (TMD) sorbed into zeolite Y containing Eu(3+) ions and 2,2'-bipyridine (samples abbreviated as ZYEBT) has been investigated.Decomposition of TMD yields, by energy transfer processes, chemiluminescence (CL) characteristic of the Eu(3+) ion.At loading levels corresponding to an upper-limit average of 0.5, 1.0, and 2.0 TMD molecules per unit cell, the CL decay curves are nonexponential at short times; at longer times, roughly exponential curves are characterized by a unimolecular rate constant k.Analyses of the long-time decays based on an Arrhenius expression for the rate constant provide evidence for a kinetic compensation effect: plots of log k vs. the activation energy Ea as a function of TMD loading level are linear.Solution data (benzene, benzonitrile) fall on the same line, suggesting that TMD decomposes by a common rate-limiting mechanism in these various environments.The Arrhenius parameters (Ea and the pre-exponential factor A) are smaller than the solution values and increase with TMD loading.When TMD is sorbed to the extent of an upper-limit average of ca. 7 molecules per unit cell, CL decay curves are initially nearly flat and then show an increase in decomposition rate with time.Mechanistic implications of these results are discussed.

Heterogeneous hydrogenation catalyses over recyclable Pd(0) nanoparticle catalysts stabilized by PAMAM-SBA-15 organic-inorganic hybrid composites

Jiang, Yijun,Gao, Qiuming

, p. 716 - 717 (2006)

Pd(0) nanoparticle catalysts stabilized by Gn-PAMAM-SBA-15 (n = 1-4) organic-inorganic hybrid composites were successfully prepared. Heterogeneous hydrogenation reaction of allyl alcohol over the Pd(0)-Gn-PAMAM-SBA-15 catalysts showed their high activities with TOFs of 2185, 2266, 711, and 739 and selectivities of 79.0, 82.0, 93.4, and 91.4%, respectively. The activity over the Pd(0)-G4-PAMAM-SBA-15 catalyst was 1.5 times that over the fourth generation PAMAM encapsulated Pd(0) homogeneous catalyst. These catalysts can be easily recovered, reused multiple times, and preserved for one month in the air, maintaining high catalytic efficiencies. Copyright

Reaction of Arylmethanes and Heteroarylmethanes with the tert-Butoxy Radical

Mahiou, Belaid,Gleicher, Gerald Jay

, p. 1555 - 1559 (1987)

The relative rates of hydrogen atom abstraction from a series of 13 homoaryl- and heteroarylmethanes by the tert-butoxy radical were determined at 70 deg C.The attacking radical was photochemically generated from di-tert-butyl peroxide.A relatively small range of relative rates (factor of 7) has been found among the compounds studied; however, significant position variation among isomers is noted.The relative reactivities of the homoaryl- and heteroarylmethanes can be correlated with various calculated energy differences obtained from both HMO and standard semiempirical SCF-MO methods.Fairly good correlations were obtained by use of a carbocation model for the transition state (correlation coefficient 0.92).Much poorer correlations were obtained when a radical model was used for the transition state with either the HMO or SCF-MO approach (maximum correlation coefficient 0.49).This suggests that considerable charge development must be associated with the transition state of this reaction.

Cleavage of the carbon-carbon bond in α-glycols under the action of bismuth(v) derivatives

Dolganova,Dodonov,Zinov'eva,Prezhbog

, p. 1164 - 1166 (1997)

Di(tert-butylperoxy)triphenylbismuth and the triphenylbismuth - tert-butyl hydroperoxide system react with 2,3-dimethylbutane-2,3-diol, benzopinacol, butane-2,3-diol, and ethane-1,2-diol with the cleavage of the C - C bond of α-glycol to form carbonyl compounds. Both heterolytic (through formation of cyclic triphenylbismuth glycolate) and homolytic cleavage occur.

Kinetics of the reaction between dimethyldioxirane and 2-methylbutane

Kazakov,Khusnullina,Kabal'nova,Khursan,Shereshovets

, p. 1690 - 1693 (1997)

The kinetics of the reaction between dimethyldioxirane and 2-methylbutane in acetone solutions were studied spectrophotometrically at 25°C. The radical-chain induced decomposition of dioxirane proceeding with the participation of the carbon-centered radicals follows the first-order kinetic law. The reaction is inhibited by dioxygen. In the presence of O2, the dimethyldioxirane consumption is due to the homolysis of the O-O bond (at a rate constant of 6.3·10-4 s-1) followed by attack of the C-H bond of 2-methylbutane by the biradical formed. The rate constant of the reaction between the alkyl radical and dimethyldioxirane was estimated.

Aerobic oxidation of pinacol by vanadium(V) dipicolinate complexes: Evidence for reduction to vanadium(III)

Hanson, Susan K.,Tom Baker, R.,Gordon, John C.,Sutton, Andrew D.,Thorn, David L.,Scott, Brian L.

, p. 428 - 429 (2009)

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Binuclear iron complexes with acyclic Schiff bases based on 4-tert-butyl-2,6-diformylphenol: Synthesis, properties, and use in catalytic partial oxidation of isobutane

Rodionova,Borisova,Smirnov,Ordomsky,Moiseeva,Pankratov

, p. 1201 - 1209 (2013)

New binuclear iron complexes with acyclic Schiff bases based on 4-tert-butyl-2,6-diformylphenol and amino acids methionine and histidine were synthesized. The composition and inferred structure of the complexes were studied by elemental analysis, IR spectroscopy, Moessbauer spectroscopy, and electrochemical methods. The synthesized complexes were studied in catalytic reactions of partial oxidation of isobutane to tert-butyl alcohol and decomposition of tert-butyl hydroperoxide. The activity and selectivity of the complex depend on the nature of the bridging group between two iron ions and are independent of the amino acid environment.

Acetic Acid Ketonization over Fe3O4/SiO2 for Pyrolysis Bio-Oil Upgrading

Bennett, James A.,Parlett, Christopher M. A.,Isaacs, Mark A.,Durndell, Lee J.,Olivi, Luca,Lee, Adam F.,Wilson, Karen

, p. 1648 - 1654 (2017)

A family of silica-supported, magnetite nanoparticle catalysts was synthesised and investigated for continuous-flow acetic acid ketonisation as a model pyrolysis bio-oil upgrading reaction. The physico-chemical properties of Fe3O4/SiO2 catalysts were characterised by using high-resolution transmission electron microscopy, X-ray absorption spectroscopy, X-ray photo-electron spectroscopy, diffuse reflectance infrared Fourier transform spectroscopy, thermogravimetric analysis and porosimetry. The acid site densities were inversely proportional to the Fe3O4 particle size, although the acid strength and Lewis character were size-invariant, and correlated with the specific activity for the vapour-phase acetic ketonisation to acetone. A constant activation energy (~110 kJ mol?1), turnover frequency (~13 h?1) and selectivity to acetone of 60 % were observed for ketonisation across the catalyst series, which implies that Fe3O4 is the principal active component of Red Mud waste.

Kinetics and mechanism of the thermal decomposition reaction of acetone cyclic diperoxide in methyl tert-butyl ether solution

Leiva, Laura C.,Jorge, Nelly L.,Romero, Jorge M.,Cafferata, Lazaro F.R.,Gomez Vara, Manuel E.

, p. 302 - 307 (2004)

The thermal decomposition reaction of acetone cyclic diperoxide (3,3,6,6-tetramethyl-1,2,4,5-tetroxane, ACDP), in the temperature range of 130.0-166.0°C and initial concentrations of range 0.4-3.1 × 10-2 mol kg-1 has been studied in methyl t-butyl ether solution. The thermolysis follows first-order kinetic laws up to at least ca 60% ACDP conversion. Under the experimental conditions, the activation parameters of the initial step of the reaction (ΔH# = 33.6 ± 1.1 kcal mol-1; ΔS# = -4.1 ± 0.7 cal mol-1 K-1; ΔG# = 35.0 ± 1.1. kcal mol-1) and acetone, as the only organic product, support a stepwise reaction mechanism with the homolytic rupture of one of its peroxidic bond. Also, participation of solvent molecules in the reaction is postulated given an intermediate diradical, which further decomposes by C-O bond ruptures, yielding a stoichiometric amount of acetone (2 mol per mole of ACDP decomposed). The results are compared with those obtained for the above diperoxide thermolysis in other solvents.

Kinetics and mechanism of the sonolytic destruction of methyl tert- butyl ether by ultrasonic irradiation in the presence of ozone

Kang, Joon-Wun,Hoffmann, Michael R.

, p. 3194 - 3199 (1998)

The kinetics and mechanism of the sonolytic degradation of methyl tert- butyl ether (MTBE) have been investigated at an ultrasonic frequency of 205 kHz and power of 200 W L-1. The observed first-order degradation rate constant for the loss of MTBE increased from 4.1 x 10-4 s-1 to 8.5 x 10- 4 s-1 as the concentration of MTBE decreased from 1.0 to 0.01 mM. In the presence of O3, the sonolytic rate of destruction of MTBE was accelerated substantially. The rate of MTBE sonolysis with ozone was enhanced by a factor of 1.5-3.9 depending on the initial concentration of MTBE. tert-Butyl formate, tert-butyl alcohol, methyl acetate, and acetone were found to be the primary intermediates and byproducts of the degradation reaction with yields of 8, 5, 3, and 12%, respectively. A reaction mechanism involving three parallel pathways that include the direct pyrolytic decomposition of MTBE, the direct reaction of MTBE with ozone, and the reaction of MTBE with hydroxyl radical is proposed. The kinetics and mechanism of the sonolytic degradation of methyl tert-butyl ether (MTBE) have been investigated at an ultrasonic frequency of 205 kHz and power of 200 W L-1. The observed first-order degradation rate constant for the loss of MTBE increased from 4.1 × 10-4 s-1 to 8.5 × 10-4 s-1 as the concentration of MTBE decreased from 1.0 to 0.01 mM. In the presence of O3, the sonolytic rate of destruction of MTBE was accelerated substantially. The rate of MTBE sonolysis with ozone was enhanced by a factor of 1.5-3.9 depending on the initial concentration of MTBE. tert-Butyl formate, tert-butyl alcohol, methyl acetate, and acetone were found to be the primary intermediates and byproducts of the degradation reaction with yields of 8, 5, 3, and 12%, respectively. A reaction mechanism involving three parallel pathways that include the direct pyrolytic decomposition of MTBE, the direct reaction of MTBE with ozone, and the reaction of MTBE with hydroxyl radical is proposed.

The Selective Oxidation of Primary Alcohols to Aldehydes by O2 Employing a Trinuclear Ruthenium Carboxylate Catalyst

Bilgrien, Carl,Davis, Shannon,Drago, Russell S

, p. 3786 - 3787 (1987)

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Zirconia catalysed acetic acid ketonisation for pre-treatment of biomass fast pyrolysis vapours

Jahangiri, Hessam,Osatiashtiani, Amin,Bennett, James A.,Isaacs, Mark A.,Gu, Sai,Lee, Adam F.,Wilson, Karen

, p. 1134 - 1141 (2018)

Crude pyrolysis bio-oil contains significant quantities of carboxylic acids which limit its utility as a biofuel. Vapour phase ketonisation of organic acids contained within biomass fast-pyrolysis vapours offers a potential pre-treatment to improve the stability and energy content of resulting bio-oils formed upon condensation. Zirconia is a promising catalyst for such reactions, however little is known regarding the impact of thermal processing on the physicochemical properties of zirconia in the context of it's corresponding reactivity for the vapour phase ketonisation of acetic acid. Here we show that calcination progressively transforms amorphous Zr(OH)4 into small tetragonal ZrO2 crystallites at 400 °C, and subsequently larger monoclinic crystallites >600 °C. These phase transitions are accompanied by an increase in the density of Lewis acid sites, and concomitant decrease in their acid strength, attributed to surface dehydroxylation and anion vacancy formation. Weak Lewis acid sites (and/or resulting acid-base pairs) are identified as the active species responsible for acetic acid ketonisation to acetone at 350 °C and 400 °C, with stronger Lewis acid sites favouring competing unselective reactions and carbon laydown. Acetone selectivity is independent of acid strength.

Thermal decomposition of tert-butyl peroxide in a gas chromatographic reactor: A comparison of kinetic approaches

Skrdla, Peter J.

, p. 386 - 393 (2004)

The thermal decomposition of tert-butyl peroxide is investigated utilizing both the column and the injection port of a commercial gas chromatograph (GC) as chemical reactors. Using the injector liner as the reactor, the chromatographic peak areas of the reactant, measured at various injector temperatures, are used in the determination of the activation energy of the decomposition (Ea). With the column serving as the reactor, both the reactant peak areas and the product peak shapes are similarly utilized for this purpose. Values of Ea obtained using different mathematical treatments for each of the three approaches are found to range from 115 to 164 kJ/mol. Of these methods, the column reactor approach utilizing peak area measurements (referred to as PACR, for "peak area, column reactor") is found to be far superior in terms of its speed, robustness, and its accuracy in determining Ea. The PACR method's effectiveness can be largely attributed to the mathematical treatment that is described in the approach.

Aldol condensation of acetic acid and formaldehyde to acrylic acid over a hydrothermally treated silica gel-supported B-P-V-W oxide

Khalameida, S.,Khyzhun, O.,Kubitska, I.,Nebesnyi, R.,Pavliuk, A.,Pikh, Z.,Sydorchuk, V.,Voronchak, T.

, (2020)

Supported on silica B-P-V-W-Ox catalysts of the aldol condensation process, subjected to hydrothermal treatment (HTT), were synthesized and characterized. It was found that HTT of silica has a significant effect on catalyst texture, namely specific surface area, pore size. These properties affect the distribution of the active phase on the support surface. It was suggested that this is the reason of change in acid-base characteristics of the catalysts. It was observed that HTT at 100?150 °C leads to increase in surface, available for the reagents, ability to sorb acetic acid, decrease of acidity, improving catalytic activity and selectivity. It had been demonstrated that HTT allows to increase acrylic acid yield up to 67.6 % which is 10 % higher compared to that for catalyst supported on initial silica. The HTT of silica support before the active phase deposition is suggested as a cheap and efficient way to improve catalytic performance of B-P-V-W-Ox/SiO2 catalysts.

Unpromoted and K2O-Promoted Cobalt Molybdate as Catalysts for the Decomposition of Acetic Acid

Halawy, Samih A.

, p. 371 - 380 (2003)

Unpromoted cobalt molybdate was prepared from Co(NO3) 2 · 6H2O and (NH4)6Mo 7O24 · 4H2O, then calcined between 350 and 600°C for 5 h. K2O (10 w%), as a promoter, was added to the calcined sample at 350°C from two different sources (i.e. KOH and KNO 3) and was subjected to further calcination at 350°C for 5 h. The catalytic activity of unpromoted catalysts towards the vapour phase decomposition of CH3COOH was greatly influenced by the increase in the calcination temperature. This is attributed to the diminution of both S BET and their dual acidic-basic characters. The promoted sample from the KOH source was found to be the most active of the catalysts studied. This is due to its high population of both acidic-basic surface sites and the formation of two new phases. XRD and FTIR analyses of the used catalysts, after the decomposition reaction of acetic acid, showed a remarkable change in its structure compared with the parent samples.

Reaction Mechanism of 2-Propanol Dehydrogenation with a Carbon-Supported Ru-Pt Composite Catalyst in the Liquid Phase

Ando, Yuji,Yamashita, Masaru,Saito, Yasukazu

, p. 2045 - 2049 (2003)

The reaction mechanism of dehydrogenation of 2-propanol substrates with and without deuterium-substitution with the Ru-Pt/carbon catalyst was studied to obtain strategies for catalyst designing suitable to direct 2-propanol fuel cells (D2PFC) and the catalyst-assisted chemical heat pump system. The Ru-Pt/carbon composite catalyst gave kinetic isotope effects of 1.54 and 1.96 for dehydrogenation at 82.4°C from (CH3)2CHOD and (CH3)2CDOH, respectively, which were contrasted to the corresponding magnitudes of 1.69 and 1.57 with a Ru/carbon catalyst and those of 1.13 and 1.81 with a Pt/carbon catalyst. The rate constants of dehydrogenation as a function of the H/D ratio in molecular hydrogen suggested that the step to form molecular hydrogen from surface hydrogen species was slow on the Ru catalyst, whereas the step to split the methine C-H bond was rather difficult for the Pt and Ru-Pt catalysts. Reflecting the facile dissociation at the hydroxy group on the catalyst surface, deuterium transfer from the hydroxy to the methyl groups of both acetone and 2-propanol proceeded tremendously for (CH3)2CHOD.

-

Japp,Streatfeild

, p. 270 (1882)

-

Products of the Gas-Phase OH Radical-Initiated Reactions of 4-Methyl-2-Pentanone and 2,6-Dimethyl-4-Heptanone

Atkinson, Roger,Aschmann, Sara M.

, p. 261 - 276 (1995)

The gas-phase reactions of OH radical with 4-methyl-2-pentanone and 2,6-dimethyl-4-heptanone have been investigated in the presence of NOx.Acetone and 2-methylpropanal were identified and quantified as products of both reactions.The acetone yield from 2,6-dimethyl-4-heptanone increased after addition of NO to reacted mixtures, indicating that acetone is formed through the intermediary of an acyl radical.The acetone and 2-methylpropanal formation yields were determined to be 0.78 +/- 0.06 and 0.071 +/- 0.011, respectively, from 4-methyl-2-pentanone and 0,68 +/- 0.11 and 0.385 +/- 0.034, respectively, from 2,6-dimethyl-4-heptanone.The possible reaction mechanisms are discussed and compared with these product data, and it is concluded that the experimental data provide direct evidence for isomerization of the (CH3)2CHCH2C(O)CH2C(O.)(CH3)2 alkoxy radical formed from 2,6-dimethyl-4-heptanone.However, the isomerization rates of the alkoxy radicals formed from the ketones depend on whether the H-atom abstracted is on a carbon atom α or β to the >C=O group, with H-atom abstraction from C-H bonds on the β carbon atoms being significantly faster than from C-H bonds on the α carbon atoms.

Reactions Involving Electron Transfer at Semiconductor Surfaces. Part 12.- Nature and Origins of Photoactivity on Oxides of 3d Transition Metals for Elimination Reactions of Secondary Alcohols

Cunningham, Joseph,Hodnett, Benjamin K.,Ilyas, Mohammad,Leahy, Edward M.,Tobin, John P.

, p. 3297 - 3306 (1982)

Activity for conversions of the vapours of propan-2-ol and butan-2-ol into products corresponding formally to elimination of H2,H2O or a (Cα-Cβ) bond from the parent alcohol were compared for oxides of the 3d transition metals under thermal- and photo-activation.Use of a gas-chromatographic, continuous reactant-flow technique with f.i.d. detection favoured the detection of products corresponding to a large turnover per surface site (t.a.p.s.).Under these conditions photoenhancement of the (-H2) and (Cα-Cβ) products at significant levels was detected only over ZnO and TiO2 and in the presence of gaseous oxygen.Such photocatalytic activity, and the contrasting absence of photoactivity continuing to high turnover over oxides featuring cations with partially filled 3d levels, is attributed to predominance and persistence of an O(1-)-type character and reactivity only for holes photogenerated in the diamagnetic ZnO and TiO2 samples.Photoassisted reaction of alcohol with several oxides at t.a.p.s. ca. 1, i.e. with the first monolayer of those oxides, could be observed using a more sensitive mass-spectrometric technique.This also revealed incorporation of oxygen-18 into acetone produced from propan-2-ol under these conditions, and the origins of this exchange at low t.a.p.s. are considered.Poisoning experiments employing a gas-chromatographic pulsed reactant technique at low t.a.p.s. provide evidence that photoassisted activity on ZnO involves photoinitiated one-electron transfer processes.

-

Williams et al.

, p. 1190 (1956)

-

Uncatalyzed and amine catalyzed decarboxylation of acetoacetic acid: An examination in terms of No Barrier Theory

Guthrie, J. Peter

, p. 32 - 52 (2002)

Rate constants for decarboxylation of acetoacetic acid, its anion, and its imine with aminoacetonitrile have been calculated from equilibrium constants and distortion energies using No Barrier Theory. The mechanisms of decarboxylation of both acetoacetic acid and its imine involve preequilibrium formation of the zwitterion.

Kinetics of one-stage Wacker-type oxidation of C2-C4 olefins catalysed by an aqueous PdCl2-heteropoly-anion system

Kozhevnikov,Lambert,Derouane

, p. 445 - 450 (2002)

The steady-state kinetics of the one-stage Wacker oxidation of gaseous olefins, e.g., ethylene, propylene, and 1-butene by oxygen catalyzed by the Pd(II)/heteropoly anions-3 redox system to form, respectively, acetaldehyde, acetone, and methyl ethyl ketone in aqueous solution was studied. The catalytic system involved an aqueous solution of Pd(II) chloride (0.05-2 mM Pd(II), [Pd(II)]/[Cl-] = l: 50) and Keggin-type heteropoly anions [PMo9V3O40]6-(50 mM), at 20°-50°C. The reactivity of olefins increases in the following order: ethylene ≤ 1-butene propylene; but the total range was only a factor of 3. The oxidation of ethylene and propylene occurred without any complication. The oxidation of 1-butene was accompanied by double-bond migration to form 2-butene, apparently proceeding through relatively stable π-allyl Pd(II) complexes. Use of a flow reactor with continuous removal of the products from the catalyst solution could reduce their overoxidation.

The direct formation of ketones by reaction of methyl- and aryl-(carbonyl)(iodo)pentamethylcyclopentadienylrhodium complexes with organic iodides

Fanizzi, Francesco P.,Sunley, Glenn J.,Maitlis, Peter M.

, p. C31 - C32 (1987)

reacts with methyl iodide to give and arylCOMe; similar reactions occur between and RI to give the ketones RCOMe (R = Ph, Me, Et, or Pr).

EFFECT OF PRESSURE ON THE DECOMPOSITION OF 2-TERT-BUTYL PEROXIDE IN SOLUTION

Zhulin, V. M.,Khueidzha, I.,Kabotyanskaya, E. B.,Koreshkov, Yu. D.

, p. 1739 - 1742 (1990)

A study was carried out on the effect of pressure up to 1400 MPa on the homolytic decomposition of di-tert-butyl peroxide (DTBP) at 403 K in 2-methoxy- (I) and 2-ethoxytetrahydropyran (II) as well as in a mixture of 30 mole percent (I) and 70 mole percent benzene.Spline approximation of the experimental pressure dependence of the logarithm of the decomposition rate constant (kd) gave the continuous dependence of the volumetric activation effect (ΔV excit.) on pressure.The value of ΔV excit. at atmospheric pressure (ΔV excit.0) and the nature of the change of ΔV excit. with increasing pressure were found to depend on the nature of the solvent.This dependence is difficult to explain in the framework of the accepted transition state theory.

Physical and catalytic properties of MgO prepared using citric acid

Nakayama, Tomohiro,Sato, Satoshi,Nozaki, Fumio

, p. 2107 - 2110 (1996)

The physical properties, particularly the pore structure and specific surface area, of MgO prepared using citric acid was investigated. Both the specific surface area and the pore volume increased steeply with the weight loss at around 600 K at which citric acid was decomposed. The pore size distribution of the sample was controlled by the ratio of citric acid and the temperature of heat treatment. In a catalytic decomposition of 4-hydroxy-4-methyl-2-pentanone into acetone, the reaction rate was proportional to the specific surface area of the sample, and the catalysts prepared by this technique had high reaction rates because of their high specific surface areas.

Propane selective oxidation on alkaline earth exchanged zeolite Y: Room temperature in situ IR study

Xu, Jiang,Mojet, Barbara L.,Van Ommen, Jan G.,Lefferts, Leon

, p. 4407 - 4413 (2003)

The effect of zeolite Y ion-exchanged with a series of alkaline-earth cations on selective propane oxidation at room temperature was studied with in situ IR spectroscopy. Isopropylhydroperoxide was a reaction intermediate and could be decomposed into acetone and water. BaY was active at room temperature. The reaction rate increased in the order BaY MgY SrY CaY based on the rate of formation of adsorbed acetone. The acetone/water ratio increased with cation size, while no other products could be detected. The acetone/isopropylhydroperoxide ratio decreased with decreasing number of Bronsted acid sites. A two-step mechanism with two different active sites was proposed. Propane conversion into isopropylhydroperoxide took place on cations, while acetone decomposition occurred by Bronsted acid sites.

Experimental and theoretical studies of the elimination kinetics of 3-hydroxy-3-methyl-2-butanone in the gas phase

Graterol, Mariana,Rotinov, Alexandra,Cordova, Tania,Chuchani, Gabriel

, p. 595 - 601 (2005)

The kinetics of the gas-phase elimination of 3-hydroxy-3-methyl-2-butanone was investigated in a static system, seasoned with allyl bromide, and in the presence of the free chain radical inhibitor toluene. The working temperature and pressure range were 439.6-4-89.3°C and 81-201.5 Torr (1 Torr = 133.3 Pa), respectively. The reaction was found to be homogeneous, unimolecular and to follow a first-order rate law. The products of elimination are acetone and acetaldehyde. The temperature dependence of the rate coefficients is expressed by the following equation: log[k1(s-1)] = (13.05 ± 0.53) - (229.7 ±5.3) kJ mol-1 (2.303RT)-1. Theoretical estimations of the mechanism of this elimination suggest a molecular mechanism of a concerted non-synchronous four-membered cyclic transition-state process. An analysis of bond order and natural bond orbital charges suggests that the bond polarization of C(OH) - C(=O) -, in the sense of C(OH) δ+...C(=O)δ-, is rate limiting in the elimination reaction. The rate coefficients obtained experimentally are in reasonably good agreement with the theoretical calculations. The mechanism of 3-hydroxy-3-methyl-2-butanone elimination is described. Copyright

Electron-Transfer Conversion of Isopropylideneadamantane to its Dioxetane

Nelsen, Stephen F.,Kapp, Daniel L.,Teasley, Mark F.

, p. 579 - 580 (1984)

Adamantylideneadamantane (1) yields its dioxetane 2 by reaction with 3O2 and catalytic tris(o,p-dibromophenyl)aminium hexachloroantiminate (4) at -78 deg C in CH2Cl2 with a chain length of over 800.Isopropylideneadamantane (5) produces its dioxetane 6 under the same conditions with a chain length of greater than 60.

Mechanism of the Wacker Oxidation of Alkenes over Cu-Pd-Exchanged Y Zeolites

Espeel, P. H.,Peuter, G. De,Tielen, M. C.,Jacobs, P. A.

, p. 11588 - 11596 (1994)

The catalytic potential of CuPd zeolites with faujasite topology in the Wacker oxidation of 1-alkenes with dioxygen is reported and compared with that of a homogeneous PdCl2-CuCl2 salt solution.The influence of water, oxygen, and alkene partial pressure on the rate of oxidation and the use of different alkenes and perdeuterated ethene as substrate allowed to establish similarities between the heterogeneous and homogenous system as well as specific zeolite effects.In situ IR and ESR spectroscopy of a working catalyst allowed to propose an active site consisting of a trinuclear Cu-O-Pd-O-Cu cationic complex and a catalytic cycle for the Wacker oxidation in which the reoxidation of Cu+ by dioxygen or of Pd0 by zeolite Cu2+ is rate determining.Diagnostic probing of the phenomena with CO in IR and ESR confirmed this picture.

A common feature of H2-assisted HC-SCR over Ag/Al 2O3

Yu, Yunbo,He, Hong,Zhang, Xiuli,Deng, Hua

, p. 1239 - 1245 (2014)

CH4, C2H2, C2H4, C3H6, and C3H8 were selected as reductants for selective catalytic reduction (SCR) of NOx over Ag/Al2O3. Activity measurement showed that NOx reduction by hydrocarbons containing two- or three-carbon atoms was clearly promoted by H2 over Ag/Al2O3 at low temperatures, while such enhancement did not occur in the case of CH 4-SCR. Gas chromatography and gas chromatography coupled to a mass spectrometer analysis showed that the partial oxidation of hydrocarbons with more than one carbon atom was triggered at low temperatures by H2 addition over Ag/Al2O3. On the surface of Ag/Al 2O3, in situ diffuse reflectance infrared Fourier transform spectra indicated that this enhancement mainly originated from the formation of reactive enolic species, which is a common feature of H 2-assisted HC-SCR. the Partner Organisations 2014.

Effect of Axial Azide on the Selective, Low Temperature Metalloporphyrin-catalysed Reactions of Isobutane with Molecular Oxygen

Ellis, Paul E.,Lyons, James E.

, p. 1187 - 1188 (1989)

Azido(tetraphenylporphyrinato) complexes of Cr(III), Mn(III), and Fe(III) catalyse selective, low temperature hydroxylation of isobutane with molecular oxygen and provide many turnovers in the absence of added co-reductants.

Effect of Pressure on the Thermolysis of Nitroalkanes in Solution

Wang, Jiang,Brower, Kay R.,Naud, Darren L.

, p. 9048 - 9054 (1997)

The effect of pressure up to 1.1 GPa on the rates of decomposition of two acidic nitroalkanes, nitromethane and 2-nitropropane, was measured. The mechanisms of thermolysis are inferred from kinetic studies and product analysis. The rate-controlling step for nitromethane decomposition in toluene at 230°C at low pressures is homolysis of the C-N bond. Beyond 20% conversion, the decomposition is autocatalytic. At high pressure, nitromethane has another reaction path which supplants homolysis. It is proposed that nitromethane forms an intermediate by cyclization of its aci-form. The high-pressure process is characterized by a first-order rate law without primary kinetic isotope effect, a low activation energy (28.5 kcal/mol), a negative activation volume (-5.5 mL/mol), and formation of products which cannot be attributed to radical intermediates. At high conversion, the reaction becomes autocatalytic as a result of accumulation of water leading to formation of products explainable by the Nef reaction. 2-Nitropropane is less stable than nitromethane. Pressure powerfully accelerates its decomposition owing to its activation volume averaging -11.2 mL/mol from 0.1 to 1.1 GPa. It is believed to cyclize via the aci-form like nitromethane. 2,2-Dinitropropane does not have a hydrogen and cannot tautomerize. In earlier work it was found to have a homolytic mechanism at high pressure. Therefore, the decomposition pathways of nitroalkanes in aprotic solvents are determined not only by the conditions but also by the availability of a hydrogen.

COMPARATIVE HAMETT STUDIES OF IMIDOYL, BENZYLIC, ALDEHYDIC HYDROGENS TRANSFER AND RELATED REACTION BY t-BUTOXYL RADICAL.

Kim, Sung Soo,Koo, Haeng Mo,Choi, Seung Yong

, p. 891 - 894 (1985)

The polar transition states involved in the hydrogen transfer reactions of N-benzylideneanilines, toluenes, benzaldehydes, and anisoles by t-butoxyl radical in benzene at 130 deg C have been comparatively discussed in terms of the values of the ? and the koa/kd.

Products and mechanism of the reaction of OH radicals with 2,2,4-trimethylpentane in the presence of NO

Arey,Atkinson,Atkinson,Aschmann

, p. 625 - 632 (2002)

Alkanes are important constituents of gasoline fuel and vehicle exhaust, with branched alkanes comprising a significant fraction of the total alkanes observed in urban areas. The products and mechanism of the OH radical-initiated reaction products and mec

Insights into the improvement effect of Fe doping into the CeO2 catalyst for vapor phase ketonization of carboxylic acids

Lu, Feipeng,Jiang, BinBo,Wang, Jingdai,Huang, Zhengliang,Liao, Zuwei,Yang, Yongrong

, p. 22 - 33 (2018)

The conversion of carboxylic acid through ketonization process reduces O-atoms and increases C[sbnd]C bonds, which can provide attractive routes for upgrading biomass feedstocks into biofuels. The key factors influencing the surface ketonization activity over CeO2-based oxides catalysts remain matters of active discourse. Here, a series of Ce1-xFexO2-δ catalysts were investigated for vapor-phase ketonization of acetic and propionic acid. The catalysts were characterized in detail using various physico-chemical techniques both before and after reaction to gain understanding of the ketonization process. The turnover frequency (TOF) based on the basic sites changed with the Fe content. The Ce0.8Fe0.2O2-δ sample showed the prominent ketonization activity with the highest TOF value. On one hand, for samples with a lower Fe addition (x 2-like solid solution with numerous Ce-O-Fe species showed a dramatic increase in surface oxygen vacancies. These oxygen vacancies were beneficial to catalytic performance. Moreover, the superior redox properties with weaken M[sbnd]O bonds of Ce-O-Fe species thereby promote the ketonization activity. On the other hand, the higher Fe addition (x > 0.3) caused the damage of the Ce-O-Fe structure, thus reducing ketonization activity. Notably, the investigation of the reaction temperature regime of Ce0.8Fe0.2O2-δ sample directly proved the existence of surface redox cycle during the ketonization process.

Ethanol Steam Reforming by Ni Catalysts for H2 Production: Evaluation of Gd Effect in CeO2 Support

Assaf, Elisabete M.,Ferreira, Gabriella R.,Lucrédio, Alessandra F.,Nogueira, Francisco G. E.

, (2022/01/19)

Abstract: Ni-based catalysts supported on CeO2 doped with Gd were prepared in this work to investigate the role of gadolinium on ethanol conversion, H2 selectivity, and carbon formation on ethanol steam reforming reaction. For this, catalysts containing 5 wt% of Ni impregnated on supports of ceria modified with different amounts of Gd (1, 5, and 10 wt%) were used. Ex-situ studies of XRPD suggest an increase of the lattice parameters, indicating a solid solution formation between Gd and Ce. Results of TPR showed an increase in metal-support interactions as the content of Gd increased. In situ XRPD studies indicated the formation of a GdNiO ternary phase for the catalysts containing Gd, which is in agreement with the results obtained by XANES. The catalysts were tested at three temperatures: 400?°C, 500?°C, and 600?°C. The conversion and productivity showed dependence with the Gd content and also with the temperature of the reaction. After the catalytic tests, catalysts containing Gd presented filamentous carbon possible due to a change in the reaction pathway. The highest ethanol conversion and H2 productivity were obtained at 600?°C for all catalysts and the best catalyst at this temperature was 5Ni_5GdCeO2. The promising performance of this catalyst may be associate with the lowest formation of GdNiO ternary phase, among the catalysts containing Gd, which means more Ni0 active species available to convert ethanol. Graphical Abstract: [Figure not available: see fulltext.]

Carbonylative Polymerization of Epoxides Mediated by Tri-metallic Complexes: A Dual Catalysis Strategy for Synthesis of Biodegradable Polyhydroxyalkanoates

Li, Wen-Bing,Liu, Ye,Lu, Xiao-Bing,Yang, Jin-Chuang,Yang, Jun

supporting information, (2022/01/20)

Polyhydroxyalkanoates (PHAs) are a unique class of commercially manufactured biodegradable polyesters with properties suitable for partially substituting petroleum-based plastics. However, high costs and low volumes of production have restricted their application as commodity materials. In this study, tri-metallic complexes were developed for carbonylative polymerization via a dual catalysis strategy, and 17 products of novel PHAs with up to 38.2 kg mol?1 Mn values were discovered. The polymerization proceeds in a sequential fashion, which entails the carbonylative ring expansion of epoxide to β-lactone and its subsequent ring-opening polymerization that occurs selectively at the O-alkyl bond via carboxylate species. The wide availability and structural diversity of epoxide monomers provide PHAs with various structures, excellent functionalities, and tunable properties. This study represents a rare example of the preparation of PHAs using epoxides and carbon monoxide as raw materials.

A 3D MOF based on Adamantoid Tetracopper(II) and Aminophosphine Oxide Cages: Structural Features and Magnetic and Catalytic Properties

?liwa, Ewelina I.,Nesterov, Dmytro S.,Kirillova, Marina V.,K?ak, Julia,Kirillov, Alexander M.,Smoleński, Piotr

supporting information, p. 9631 - 9644 (2021/06/30)

This work describes an unexpected generation of a new 3D metal-organic framework (MOF), [Cu4(μ-Cl)6(μ4-O)Cu(OH)2(μ-PTAO)4]n·2nCl-EtOH·2.5nH2O, from copper(II) chloride and 1,3,5-triaza-7-phosphaadamantane 7-oxide (PTAO). The obtained product is composed of diamandoid tetracopper(II) [Cu4(μ-Cl)6(μ4-O)] cages and monocopper(II) [Cu(OH)2] units that are assembled, via the diamandoid μ-PTAO linkers, into an intricate 3D net with an nbo topology. Magnetic susceptibility measurements on this MOF in the temperature range of 1.8-300 K reveal a ferromagnetic interaction (J = +20 cm-1) between the neighboring copper(II) ions. Single-point DFT calculations disclose a strong delocalization of the spin density over the tetranuclear unit. The magnitude of exchange coupling, predicted from the broken-symmetry DFT studies, is in good agreement with the experimental data. This copper(II) compound also acts as an active catalyst for the mild oxidation and carboxylation of alkanes. The present study provides a unique example of an MOF that is assembled from two different types of adamantoid Cu4 and PTAO cages, thus contributing to widening a diversity of functional metal-organic frameworks.

Tris(pentafluorophenyl)borane-Catalyzed Formal Cyanoalkylation of Indoles with Cyanohydrins

Kiyokawa, Kensuke,Minakata, Satoshi,Urashima, Naruyo

, p. 8389 - 8401 (2021/06/28)

Despite the significant achievements related to the C3 functionalization of indoles, cyanoalkylation reactions continue to remain rather limited. We herein report on the formal C3 cyanoalkylation of indoles with cyanohydrins in the presence of a tris(pentafluorophenyl)borane (B(C6F5)3) catalyst. It is noteworthy that cyanohydrins are used as a cyanoalkylating reagent in the present reaction, even though they are usually used as only a HCN source. Mechanistic investigations revealed the unique reactivity of the B(C6F5)3 catalyst in promoting the decomposition of a cyanohydrin by a Lewis acidic activation through the coordination of the cyano group to the boron center. In addition, a catalytic three-component reaction using indoles, aldehydes as a carbon unit, and acetone cyanohydrin that avoids the discrete preparation of each aldehyde-derived cyanohydrin is also reported. The developed methods provide straightforward, highly efficient, and atom-economic access to various types of synthetically useful indole-3-acetonitrile derivatives containing α-tertiary or quaternary carbon centers.

Selective Functionalization of Hydrocarbons Using a ppm Bioinspired Molecular Tweezer via Proton-Coupled Electron Transfer

Chen, Hongyu,Wang, Lingling,Xu, Sheng,Liu, Xiaohui,He, Qian,Song, Lijuan,Ji, Hongbing

, p. 6810 - 6815 (2021/06/28)

An expanded porphyrin-biscopper hexaphyrin was introduced as a bioinspired molecular tweezer to co-catalyze functionalization of C(sp3)-H bonds. Theoretical and experimental investigations suggested that the biscopper hexaphyrin served as a molecular tweezer to mimic the enzymatic orientation/proximity effect, efficiently activating the N-hydroxyphthalimide (NHPI) via light-free proton-coupled electron transfer (PCET), at an exceptionally low catalyst loading of 10 mol ppm. The resulting N-oxyl radical (PINO) was versatile for chemoselective C-H oxidation and amination of hydrocarbons.

Process route upstream and downstream products

Process route

formic acid
64-18-6

formic acid

(3R)-3-methylcyclohexanone
13368-65-5

(3R)-3-methylcyclohexanone

acetone
67-64-1

acetone

Conditions
Conditions Yield
dextrorotatory form;
formic acid
64-18-6

formic acid

isopulegone
29606-79-9

isopulegone

(3R)-3-methylcyclohexanone
13368-65-5

(3R)-3-methylcyclohexanone

acetone
67-64-1

acetone

Conditions
Conditions Yield
d-isopulegone;
2,6-dimethyl-5-oxo-heptanoic acid
74457-59-3

2,6-dimethyl-5-oxo-heptanoic acid

2-methylglutaric acid
18069-17-5

2-methylglutaric acid

acetone
67-64-1

acetone

Conditions
Conditions Yield
substance from carvenone; durch Oxidation;
chloroform
67-66-3,8013-54-5

chloroform

5-methyl-2-isopropylidenecyclopentanone
6784-16-3

5-methyl-2-isopropylidenecyclopentanone

2-methylglutaric acid
18069-17-5

2-methylglutaric acid

acetone
67-64-1

acetone

Conditions
Conditions Yield
bei der Ozonspaltung;
rac-2,6-dimethylhept-5-enenitrile
54088-65-2

rac-2,6-dimethylhept-5-enenitrile

2-methylbutanedioic acid
498-21-5,636-60-2

2-methylbutanedioic acid

2-methylglutaric acid
18069-17-5

2-methylglutaric acid

acetone
67-64-1

acetone

Conditions
Conditions Yield
bei der Oxydation und nachfolgender Verseifung des Reaktionsproduktes;
2,2-dimethyl-1,3-oxathiolane
5684-31-1

2,2-dimethyl-1,3-oxathiolane

2-carboxybenzene diazonium chloride
4661-46-5

2-carboxybenzene diazonium chloride

acetone
67-64-1

acetone

phenylthioethylene
1822-73-7

phenylthioethylene

Conditions
Conditions Yield
With methyloxirane; In 1,2-dichloro-ethane; for 0.75h; Mechanism; Heating;
71%
With methyloxirane; In 1,2-dichloro-ethane; for 0.75h; Heating;
71%
octadecan-2-one
7373-13-9

octadecan-2-one

1-pentadecene
13360-61-7

1-pentadecene

(1R,2R)-1-Methyl-2-tridecyl-cyclobutanol

(1R,2R)-1-Methyl-2-tridecyl-cyclobutanol

(1R,2S)-1-Methyl-2-tridecyl-cyclobutanol

(1R,2S)-1-Methyl-2-tridecyl-cyclobutanol

acetone
67-64-1

acetone

Conditions
Conditions Yield
With n-butyl stearate; Product distribution; Irradiation; various temperatures;
1,1-dimethylethyl-1-phenylethyl peroxide
28047-94-1

1,1-dimethylethyl-1-phenylethyl peroxide

1-Phenylethanol
98-85-1,13323-81-4

1-Phenylethanol

benzaldehyde
100-52-7

benzaldehyde

acetophenone
98-86-2

acetophenone

acetone
67-64-1

acetone

<i>tert</i>-butyl alcohol
75-65-0

tert-butyl alcohol

Conditions
Conditions Yield
In chlorobenzene; at 129.2 ℃; Product distribution; Rate constant; also with styrene, dimethylaniline, and 2,6-di-tert-butyl-p-cresol (radical traps);
78.8%
3.12%
1.1%
26.2%
49.4%
t-butyl phenylperacetate
3377-89-7

t-butyl phenylperacetate

phenylacetic acid
103-82-2

phenylacetic acid

benzyl bromide
100-39-0

benzyl bromide

acetone
67-64-1

acetone

benzeneacetic acid methyl ester
101-41-7

benzeneacetic acid methyl ester

Conditions
Conditions Yield
With toluene-p-sulfonyl bromide; In benzene; at 70 ℃; for 40h; Further byproducts given;
139.7 mg
51.6 mg
153.0 mg
20.5 mg
t-butyl phenylperacetate
3377-89-7

t-butyl phenylperacetate

benzyl bromide
100-39-0

benzyl bromide

acetone
67-64-1

acetone

benzeneacetic acid methyl ester
101-41-7

benzeneacetic acid methyl ester

<i>tert</i>-butyl alcohol
75-65-0

tert-butyl alcohol

Conditions
Conditions Yield
With toluene-p-sulfonyl bromide; In benzene; at 70 ℃; for 40h; Further byproducts given;
139.7 mg
51.6 mg
20.5 mg
4.0 mg

Global suppliers and manufacturers

This product is a nationally controlled contraband, and the Lookchem platform doesn't provide relevant sales information.
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