123-42-2Relevant articles and documents
-
Lorette
, p. 346 (1957)
-
Calcium oxide supported on monoclinic zirconia as a highly active solid base catalyst
Frey, Anne Mette,Van Haasterecht, Tomas,De Jong, Krijn P.,Bitter, Johannes Hendrik
, p. 3621 - 3628 (2013)
Calcium oxide supported on ZrO2 is a highly active catalyst for base-catalyzed reactions such as aldol-type reactions and transesterification reactions. The role of key parameters during preparation, that is, impregnation versus precipitation, heat treatment, and metal oxide loading on the basicity and catalytic activity were investigated for CaO supported on ZrO2. An impregnation of 10 wt % CaO on monoclinic zirconia followed by heat treatment at 600°C resulted in high activity for the self-condensation reaction of acetone. An evaluation of a series of CaO/ZrO2 samples with different loadings showed that the activity increased for impregnated amounts per gram catalyst of 0-10 wt % CaO, and at higher loading the activity decreased as a result of a decrease in dispersion. The number of strong base sites (calculated from CO2 desorbed at temperatures higher than 625°C) correlated with the activity. For MgO, CaO, SrO, and BaO on zirconia the catalytic activity increased as the ionic radius of the metal cation increased, suggesting the impact of base strength on catalytic performance. Look at the strong base! If prepared in an optimized way, CaO/ZrO2 is a highly active solid base catalyst. Calcination temperature and the preparation method (impregnation or deposition) have a strong influence on the number of strong base sites, which correlate positively with the activity of the material. Copyright
Analysis of Minor Components by Ultrahigh Resolution NMR. 2. Detection of 0.01percent Diacetone Alcohol in "Pure" Acetone and Direct Measurement of the Rate of the Aldol Condensation of Acetone
Maple, Steven R.,Allerhand, Adam
, p. 6609 - 6614 (1987)
Ultrahigh resolution NMR methodology permits the detection of as little as 0.01percent CH3COCH2(OH)C(CH3)2 (2) in a sample of "pure" acetone (1) of natural isotopic composition, with the use of the methyl resonances in the proton-decoupled (13)C NMR spectrum, even though the resonances of 2 are very close to those of 1.Also, all three peaks of the triplet of the (13)CH2D carbon of (13)CH2D-(12)CO-(12)CH3 are fully resolved, even though their intensity is only 0.015percent of that of the main contributor to the spectrum, (13)CH3-(12)CO-(12)CH3, and one of the peaks of the triplet is only 7 Hz away from the main acetone peak.The intensities of the (13)CH2D triplet serve as a calibrator of dynamic range accuracy in (13)C NMR measurements of relative proportions of major and minor components.After addition of aqueous sodium hydroxide to the acetone sample, the growth of the methyl carbon resonances of 2 provides a direct measurement of the rate constant for the aldol dimerization of 1 and also the equilibrium constant for this reaction.This example demonstrates the ability of ultrahigh resolution NMR to study directly the kinetics of reactions that have equilibria highly displaced toward the reagents, instead of the traditional procedure of monitoring only the kinetics of the reverse reaction by starting with pure "products".Artifacts that may interfere with the study of minor components by ultrahigh resolution NMR are discussed.
-
Hoffmann
, p. 722 (1909)
-
Kinetics by Thermometry: An Aldol Condensation Reaction
Eskendirov, Igor,Kabongo, Bukasa,Glasser, Leslie,Sokolovskii, Valery D.
, p. 991 - 994 (1995)
The princilpes of 'thermokinetic' experiments have been described, whereby the initial rates of chemical reaction in solution are determined by following the temperature rise in an adiabatic system; data are obtained within the first few seconds of mixing, and at rates of the order of one measurement s-1.The procedure has been applied to the base-catalysed condensation reaction of acetone to form diacetone alcohol, an exceptionally difficult reaction to follow because of the small extent to which the reaction proceeds.At 26 deg C, the equilibrium constant for the base-catalysed ionisation of acetone has been established as having a value of 1.2(9) l mol-1 while the rate constant for the ionic dimerisation has the value 2.5(2)E-3 mol l-1 s-1.
-
Klein,Banchero
, p. 1278,1280 (1956)
-
Design and application of the recyclable poly(l-proline-co-piperidine) catalyst for the synthesis of mesityl oxide from acetone
Xu, Lin,Huang, Jiejun,Liu, Yubing,Wang, Yining,Xu, Bolian,Ding, Kehong,Ding, Yuanhua,Xu, Qing,Yu, Lei,Fan, Yining
, p. 42178 - 42185 (2015)
Unexpectedly, l-proline/piperidine was found to be a better recyclable catalyst system than l-proline or piperidine alone in the condensation of acetone to prepare mesityl oxide (MO), an important intermediate in the chemical industry. Binding the catalyst system onto polymer resin enhanced the MO selectivity and reduced the catalyst loss. The mechanism of the bi-component catalyst system was also studied through control reactions, as well as by dynamic calculations. The MO selectivity could reach 74.4% and its isolated yield could reach 73.9%, based on the consumed acetone. Although the result does not immediately meet the requirement of industrial production, this study provides a novel organocatalyst system, which might offer a potential alternative to traditional inorganic catalysts that can be used under mild and neutral conditions.
The mechanism of catalyst deactivation and by-product formation in acetone ammoximation catalyzed by hollow titanium silicalite
Wang, Yi,Zhang, Shengjian,Zhao, Yingxian,Lin, Min
, p. 1 - 6 (2014)
The deactivation mechanism of hollow titanium silicalite (HTS) in aqueous ammoximation of acetone was investigated. Amines and polynitro-compounds, formed by alkaline autocatalytic and oxidative coupling reaction respectively, were determined to be the ma
L-Proline and thiourea co-catalyzed condensation of acetone
Xu, Lin,Wang, Fang,Huang, Jiejun,Yang, Chenggen,Yu, Lei,Fan, Yining
, p. 4076 - 4080 (2016)
Amino acid and primary amine/amide co-catalyzed acetone condensation was investigated. It was found that L-proline had overwhelming catalytic activity over other amino acids as well as the analogues with similar structures. Surprisingly, thiourea, a very cheap and stable chemical, was found to be the favorable co-catalyst. Co-catalyzed by the recyclable L-proline and thiourea, condensation of acetone led to the useful products mesityl oxide (MO), diacetone alcohol (DAA) and isophorone (IP) in the excellent 96.3% total selectivity.
Kinetics and products of the reactions of selected diols with the OH radical
Bethel, Heidi L.,Atkinson, Roger,Arey, Janet
, p. 310 - 316 (2001)
Using a relative rate method, rate constants been measured at 296 ± 2 K for the gas-phase reactions of OH radicals with 1,2-butanediol, 2,3-butanediol, 1,3-butanediol, and 2-methyl-2,4-pentanediol, with rate constants (in units of 10-12 cm3 molecule-1 s-1) of 27.0 ± 5.6, 23.6 ± 6.3, 33.2 ± 6.8, and 27.7 ± 6.1, respectively, where the error limits include the estimated overall uncertainty of ±20% in the rate constant for the reference compound. Gas chromatographic analyses showed the formation of 1-hydroxy-2-butanone from 1,2-butanediol, 3-hydroxy-2-butanone from 2,3-butanediol, 1-hydroxy-3-butanone from 1,3-butanediol, and 4-hydroxy-4-methyl-2-pentanone from 2-methyl-2,4-pentanediol, with formation yields of 0.66 ± 0.11, 0.89 ± 0.09, 0.50 ± 0.09, and 0.47 ± 0.09, respectively, where the indicated errors are the estimated overall uncertainties. Pathways for the formation of these products are presented, together with a comparison of the measured and estimated rate constants and product yields.
The enthalpy of acetone
Yerlett, T. K.,Wormald, C. J.
, p. 371 - 380 (1986)
Measurements of the specific enthalpy increment of acetone are reported; 206 measurements cover the range 373.2 to 623.2 K at pressures from 0.1 to 11.9 MPa.The overall accuracy is 0.6 per cent.The specific enthalpy of the saturated liquid and of the saturated vapour and the enthalpy of vaporization are derived from the measurements.Comparison with cubic equations of state shows that the Patel-Teja equation is the best of those tested.
Kinetics and Equilibrium Data of the Dehydration-Hydration Reaction between Diacetone Alcohol and Mesityl Oxide in Phosphoric Acid
Kim, Yong K.,Hatfield, John D.
, p. 149 - 153 (1985)
The velocities of dehydration of diacetone alcohol and hydration of mesityl oxide were studied in regions of 8.6-85.2percent phosphoric acid.Because the reactions are acid-catalyzed, the reaction velocities in both directions were increased as the acid concentration increased.The reaction kinetics fit the reversible first-order model with respect to the concentration of reactants, including the activity of water.These results are consisted with the mechanisms proposed by a previous investigator in which the rate-determining step is addition or removal of protons.Equilibrium constants were derived from solution composition and specific rate constants which agreed with each other.The equilibrium constant did not change with with acid concentration in the dilute range, but increased slightly at higher acid concentrations.The reaction velocities and the equilibrium constants increased with increasing temperature, and the activation energies were 18.8 and 12.7 kcal/mol for the dehydration and hydration reactions, respectively.
ALDOL CONDENSATION OF ACETONE IN THE TWO-PHASE SYSTEM SOLID BASE-BENZENE IN THE PRESENCE OF BENZYLTRIETHYLAMMONIUM CHLORIDE
Yufit, S.S.,Esikova, I.A.
, p. 2012 - 2016 (1984)
-
Comparative study of the catalytic behaviour of Ru(III) and Ru(VI) on the oxidation of alcohols by hexacyanoferrate(III)
Mucientes,Gabaldon,Poblete,Villarreal
, p. 236 - 240 (2004)
The oxidation reactions of 2-methyl-2,4-pentanediol upon treatment with alkaline hexacyanoferrate(III) using Ru(III) or Ru(VI) as catalysts are governed by two quasi-identical experimental rate equations, which show that both catalysts are equally effective for the oxidation of alcohols by Fe(CN)63-. The reaction mechanism proposed involves the oxidation of 2-methyl-2,4-pentanediol by the catalyst, a process that occurs through the formation of a substrate-catalyst complex. The decomposition of this complex yields Ru(IV) and a protonated ketone (owing to a hydride transfer from the α-C - H bond of the alcohol to the oxoligand of ruthenium) in the case of Ru(VI), but a ketyl radical and Ru(II) (hydrogen transfer) for Ru(III). The role of the co-oxidant, Fe(CN)63-, is to regenerate the catalyst. For both oxidation reactions, the rate constants of complex decomposition and catalyst regeneration have been determined. Copyright
On the Metal Cooperativity in a Dinuclear Copper–Guanidine Complex for Aliphatic C?H Bond Cleavage by Dioxygen
Sch?n, Florian,Biebl, Florian,Greb, Lutz,Leingang, Simone,Grimm-Lebsanft, Benjamin,Teubner, Melissa,Buchenau, S?ren,Kaifer, Elisabeth,Rübhausen, Michael A.,Himmel, Hans-J?rg
, p. 11257 - 11268 (2019)
Selective oxidation reactions of organic compounds with dioxygen using molecular copper complexes are of relevance to synthetic chemistry as well as enzymatic reactivity. In the enzyme peptidylglycine α-hydroxylating monooxygenase (PHM), the hydroxylating activity towards aliphatic substrates arises from the cooperative effect between two copper atoms, but the detailed mechanism has yet to be fully clarified. Herein, we report on a model complex showing hydroxylation of an aliphatic ligand initiated by dioxygen. According to DFT calculations, the proton-coupled electron-transfer (PCET) process leading to ligand hydroxylation in this complex benefits from cooperative effects between the two copper atoms. While one copper atom is responsible for dioxygen binding and activation, the other stabilizes the product of intramolecular PCET by copper–ligand charge transfer. The results of this work might pave the way for the directed utilization of cooperative effects in oxidation reactions.
Method for preparing triacetone amine
-
Paragraph 0133-0144, (2020/07/05)
An improved method is used for preparing triacetone amine while recycling the by-products. This involves treating the crude product from triacetone amine preparation, which leads to an increase in the content of compounds which react readily with ammonia. This method enables efficient recycling of the by-products formed in the synthesis of triacetone amine.
Complete Switch of Reaction Specificity of an Aldolase by Directed Evolution In Vitro: Synthesis of Generic Aliphatic Aldol Products
Junker, Sebastian,Roldan, Raquel,Joosten, Henk-Jan,Clapés, Pere,Fessner, Wolf-Dieter
supporting information, p. 10153 - 10157 (2018/07/31)
A structure-guided engineering of fructose-6-phosphate aldolase was performed to expand its substrate promiscuity toward aliphatic nucleophiles, that is, unsubstituted alkanones and alkanals. A “smart” combinatorial library was created targeting residues D6, T26, and N28, which form a binding pocket around the nucleophilic carbon atom. Double-selectivity screening was executed by high-performance TLC that allowed simultaneous determination of total activity as well as a preference for acetone versus propanal as competing nucleophiles. D6 turned out to be the key residue that enabled activity with non-hydroxylated nucleophiles. Altogether 25 single- and double-site variants (D6X and D6X/T26X) were discovered that show useful synthetic activity and a varying preference for ketone or aldehyde as the aldol nucleophiles. Remarkably, all of the novel variants had completely lost their native activity for cleavage of fructose 6-phosphate.