5704-20-1Relevant articles and documents
Selective Hydrogenation of Diketones on Supported Transition Metal Catalysts
Carrara,Badano,Vailard,Vera,Quiroga
, p. 461 - 470 (2019/11/13)
Abstract: The hydrogenation of α-diketones yields α-hydroxyketones or vic-diols, both compounds of great interest in fine chemistry. The reaction tests were the liquid phase hydrogenation of 2,3-butanedione and 2,3-pentanedione at mild conditions. The objectives of this work were evaluating the effect over the activity and selectivity of: (a) different transition metallic phase based catalysts supported on activated carbon, (b) the symmetry of the reactants and (c) solvents. The physicochemical characterization of the catalysts was carried out by ICP, XRD, TEM, N2 adsorption and XPS. The keto-enol equilibrium of diketones was studied by 1H-NMR. All the catalysts were active in both reactions. In terms of activity, Pt and Rh were the best active phases. For both reactants the highest selectivity towards hydroxyketones were achieved with Pd, while Ru was the most selective towards the diol. Both the activity and selectivity followed similar patterns in the hydrogenation of both diketones. The greater activity of Pt was attributed to the high dispersion of the active metal phase in this catalyst and the high efficiency of Pt for C = O bond reduction. The high selectivity of the Pd catalysts towards the intermediate product was attributed to many effects: (i) a lower interaction of the hydroxyketone with the active site as compared to the diketone, (ii) the easy reducibility of the C = C double bond on Pd, provided by the keto-enol tautomerism of diketones.
Preparation method of 2,3-pentanedione
-
Paragraph 0004; 0017-0019; 0024-0026; 0031-0033, (2018/09/08)
The invention discloses a preparation method of 2,3-pentanedione. The preparation method comprises the following steps: one or two of 3-hydroxy-2-pentanone and 2-hydroxy-3-pentanone is/are added to water and uniformly mixed with water, ozone is introduced at the temperature of 3-20 DEG C for a reaction, and 2,3-pentanedione is obtained. According to the synthesis process, ozone is adopted to oxidize the mixture containing 3-hydroxy-2-pentanone and 2-hydroxy-3-pentanone, acetic acid is adopted as a cocatalyst, reaction conditions are mild, and operation process is simple; product yield is high;cost is low; the method has the advantages of being safe and environmentally friendly, and no wastewater is produced.
Chemoenzymatic synthesis of aroma active 5,6-dihydro- and tetrahydropyrazines from aliphatic acyloins produced by baker's yeast
Kurniadi, Toshinari,Bel Rhlid, Rachid,Fay, Laurent-Bernard,Juillerat, Marcel-Alexandre,Berger, Ralf Guenter
, p. 3103 - 3107 (2007/10/03)
Twenty-five acyloins were generated by biotransformation of aliphatic aldehydes and 2-ketocarboxylic acids using whole cells of baker's yeast as catalyst. Six of these acyloins were synthesized and tentatively characterized for the first time. Subsequent chemical reaction with 1,2-propanediamine under mild conditions resulted in the formation of thirteen 5,6-dihydropyrazines and six tetrahydropyrazines. Their odor qualities were evaluated, and their odor thresholds were estimated. Among these pyrazine derivatives, 2-ethyl-3,5-dimethyl-5,6-dihydropyrazine (roasted, nutty, 0.002 ng/L air), 2,3-diethyl-5-methyl-5,6-dihydropyrazine (roasted, 0.004 ng/L air), and 2-ethyl-3,5-dimethyltetrahy-dropyrazine (bread crustlike, 1.9 ng/L air) were the most intensive-smelling aroma active compounds.
