Microwave spectra of mono-C substituted acetone, (CH3)2CO

The microwave spectra of the two mono-¹³C isotopic forms of acetone are reported for the first time. Measurements were carried out from 11 to 25 GHz with a pulsed-beam Fourier-transform microwave spectrometer. Because overall rotation interacts with the internal rotations of the methyl groups, the spectra were analyzed with an effective rotational Hamiltonian for molecules with two periodic large-amplitude internal motions. In acetone-2-¹³C, the methyl groups are equivalent; in acetone-1-¹³C, they are not. The molecular structure has been re-examined by including rotational constant data on other isotopic forms reported previously. An equilibrium structure for acetone has been derived from the observed rotational constants and vibration-rotation constants calculated from ab initio force fields.     

STUDY ON THE CATALYTIC REACTION OF ACETONE TO DIACETONE ALCOHOL

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Carbohydrate pyrolysis mechanisms from isotopic labeling: Part 3. The Pyrolysis of d-glucose: Formation of C3 and C4 carbonyl compounds and a cyclopentenedione isomer by electrocyclic fragmentation mechanisms

The flash pyrolysis of d-glucose was investigated by the use of ¹³C labeling, in conjunction with GC/MS. Co-pyrolysis of uniformly labeled and unlabeled d-glucose established the extent of unimolecular formation of each of the pyrolysis products. A complete set of singly labeled d-glucose isotopologs was used to determine the origin of specific carbons within each of the pyrolysis products. The results were compared with the expected labeling patterns that arise when the cyclic Grob 1,3-diol fragmentation and the tandem alkaline pinacol rearrangement/retro-aldol fragmentation (TAPRRAF) discovered from the pyrolysis of glycerin are used to initiate breakage of the six-carbon chain of d-glucose. The most promising rationalizations provided by this exercise are presented herein, for the formation of six C₃ and eight C₄ acyclic carbonyl-containing pyrolysis products, and for 3-cyclopentene-1,2-dione.     

An enantioselective nucleophilic addition of α,β-unsaturated trifluoromethylketones catalyzed by l-proline derivatives

An unexpected enantioselective 1,2-aldol reaction of acetone with α,β-unsaturated trifluoromethylketone catalyzed by l-proline derivative was described. The absolute configuration of the resulting chiral product was assigned based on a single crystal X-ray diffraction analysis. Structure-reactivity study of this organocatalytic system was briefly discussed. A reaction mechanism was tentatively postulated.     

高对映选择性有机催化的七元环状亚胺二苯并1,4-氧氮杂卓和丙酮的直接Mannich反应(英文)

用脯氨酸作为催化剂,研究了各种取代的二苯并1,4-氧氮杂卓衍生物类七元环状亚胺和丙酮的直接Mannich反应,该反应能高对映选择得到一系列旋光活性的含有β羰基的七元环状氮杂环化合物(93%–98%ee).用丁酮作为Mannich给体时,能得到专一的区域选择性和96%–97%ee的产物.进一步通过X射线单晶衍射分析其中一个产物的衍生物,确定了产物手性中心绝对构型为R,其它同类型产物绝对构型随后通过化学类比方法推断确认.     

(Liquid + liquid) equilibria for (water + 1-propanol or acetone + β-citronellol) at different temperatures

On this paper, experimental (liquid + liquid) equilibrium (LLE) results are presented for systems composed of β-citronellol and aqueous 1-propanol or acetone. To evaluate the phase separation properties of β-citronellol in aqueous mixtures, LLE values for the ternary systems (water + 1-propanol + β-citronellol) and (water + acetone + β-citronellol) were determined with a tie-line method at T = (283.15, 298.15, and 313.15 ± 0.02) K and atmospheric pressure. The reliability of the experimental tie-lines was verified by the Hand and Bachman equations. Ternary phase diagrams, distribution ratios of 1-propanol and acetone in the mixtures are shown. The effect of the temperature on the ternary (liquid + liquid) equilibria was examined and discussed. The experimental LLE values were satisfactorily correlated by extended UNIQUAC and modified UNIQUAC models.     

气相色谱法测定工作场所空气中正己烷、丙酮、丁酮和乙酸丁酯的含量

用气相色谱法对空气中正己烷、丙酮、丁酮和乙酸丁酯的含量进行测定。采用活性炭管采集了空气中的正己烷、丙酮、丁酮和乙酸丁酯,采用二硫化碳进行解吸,用Agilent 19091N-216HP-INNOWAX Polyethylene Glycol毛细管色谱柱分离,氢焰离子化检测器检测。正己烷、丙酮、丁酮和乙酸丁酯的检出限(3S/N)为0.43,0.30,0.44,1.7mg.L-1。方法的解吸率在86.7%～100.3%之间,相对标准偏差(n=6)在1.97%～3.89%之间。     

A novel Anderson-type polyoxometalate: hydrothermal synthesis,crystal structure,and catalytic performance of (H3O)[(3-C5H7N2)2(Cr(OH)6Mo6O18)] · 3H2O

A new Anderson polyoxometalate (H₃O)[(3-C₅H₇N₂)₂(Cr(OH)₆Mo₆O₁₈)]?·?3H₂O (3-C₅H₆N₂?=?3-aminopyridine) was hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction. Crystal data: triclinic, P 1, a?=?7.8482(8)?Å, b?=?10.1800(10)?Å, c?=?10.4103(10)?Å, α?=?88.031(3)°, β?=?78.308(2)°, γ?=?88.842(3)°, V?=?813.91?ų, Z?=?1, R(F)?=?0.0397, wR _ref(F ²)?=?0.1022, and S?=?1.076. The X-ray crystallographic study showed that the structure contains Anderson-type [Cr(OH)₆Mo₆O₁₈]^3? polyoxoanions. The title compound has high catalytic activity for the oxidation of acetone tested in a continuous-flow fixed-bed micro-reactor. When the initial concentration is 18.3?g?m^?3 in air and the flow velocity is 8.5?mL?min^?1, the acetone is completely eliminated at 160°C.     

Derived Properties of Binary Mixtures Containing (Acetone or Methanol) + Hydroxil Compounds

Abstract

This work reports values of the density, refractive index and speed of sound of the binary mixtures acetone or methanol with (2-methyl, 1-propanol, 3-methyl, 1-butanol, 1,2-ethanediol, 1,2-propanediol and 1,3-propanediol) at 298.15 K and atmosphere, as a function of the mole fraction. From the experimental values, the corresponding excess and derived magnitudes were computed (excess molar volumes, changes of refractive index on mixing and changes of isentropic compressibility on mixing), variable-degree polynomials being fitted to the results. Only expansive trend was observed for those mixtures enclosing branched alcohols. The influence of the hydroxil group in the nonideal behaviour of these mixtures were analyzed in terms of the partial molar excess volumes.     

GROMOS polarisable model for acetone

A polarisable model for acetone, COS/A, is proposed that is based on the charge-on-spring (COS) polarisation model and is compatible with the polarisable COS/D2 and COS/G2 models for liquid water. A series of acetone-water mixtures at different acetone mole fractions was simulated using the new model in conjunction with the mentioned polarisable and the non-polarisable SPC and SPC/E water models. The model was parameterised to reproduce the following liquid acetone properties: density, heat of vaporisation, surface tension, dielectric permittivity, self diffusion and heat capacity and subsequently tested in mixtures with water using different water models. For pure liquid acetone the polarisable COS/A model agrees better with experimental data than the non-polarisable Kirkwood-Buff derived force field (KBFF) model, which was parameterised using experimental data for a 0.5 mole fraction acetone-water mixture. For such mixtures the polarisable models yield better agreement with experiment than the non-polarisable models for the heat of vaporisation and dielectric permittivity, while worse agreement for diffusion. The computational cost of simulating the polarisable acetone-water mixtures is a factor of 3 to 4 higher compared with the non-polarisable models due to the increased number of interaction sites and the multiple iterations required to evaluate self-consistently the positions of the COS sites at every simulation step. The COS/A acetone model can be used in biomolecular simulations in conjunction with the mentioned polarisable water models to solvate biomolecules.