Acetone

About: Acetone is a research topic. Over the lifetime, 9458 publications have been published within this topic receiving 120867 citations. The topic is also known as: propanone & dimethylketone.

Vanillin-HCl method for condensed tannins: Effect of organic solvents used for extraction of tannins

Abstract: Tannins are generally extracted using aqueous organic solvents, mainly methanol and acetone. The presence of various concentrations of methanol in the sample containing catechin or tannins did not alter the kinetics of their reaction, but the absorbance depended on the amount of methanol in the sample; the higher the methanol, the higher was the absorbance. Acetone reacted with acidified vanillin to produce a chromogen with λmax at 548 nm, which produce a substantial error in the determination of condensed tannins. In the presence of acetone, the time courses of the reaction for catechin and tannins were different, which depended on the acetone concentration and the reaction temperature. Reaction conditions for catechin and tannins that enable their measurement in the presence of acetone are presented.

Cu/MgAl2O4 as Bifunctional Catalyst for Aldol Condensation of 5‐Hydroxymethylfurfural and Selective Transfer Hydrogenation

Abstract: Copper supported on mesoporous magnesium aluminate has been prepared as noble-metal-free solid catalyst for aldol condensation of 5-hydroxymethylfurfural with acetone, followed by hydrogenation of the aldol condensation products. The investigated mesoporous spinels possess high activity as solid-base catalysts. Magnesium aluminate exhibits superior activity compared to zinc and cobalt-based aluminates, reaching full conversion and up to 81 % yield of the 1:1 aldol product. The high activity can be correlated to a higher concentration of basic surface sites on magnesium aluminate. Applying continuous regeneration, the catalysts can be recycled without loss of activity. Focusing on the subsequent hydrogenation of aldol condensation products, Cu/MgAl2 O4 allows a selective hydrogenation and CO bond cleavage, delivering 3-hydroxybutyl-5-methylfuran as the main product with up to 84 % selectivity avoiding ring saturation. Analysis of the hydrogenation activity reveals that the reaction proceeds in the following order: CC>CO>CO cleavage>ring hydrogenation. Comparable activity and selectivity can be also achieved utilizing 2-propanol as solvent in the transfer hydrogenation, providing the possibility for partial recycling of acetone and optimization of the hydrogen management.

Triplet state of acetone in solution. Deactivation and hydrogen abstraction

Abstract: Kinetic studies of the absorption and emission of triplet acetone and the absorption of the ketyl radical, following flash excitation of acetone in a variety of solvents, are reported as well as the quantum yields of acetone disappearance.Rate constants of triplet quenching are derived and the pathways of deactivation of triplet acetone in solution are discussed.

Increase in the γ-linolenic acid content by solvent winterization of fungal oil extracted fromMortierella genus

Abstract: The fungal oil extracted fromMortierella ramanniana var.angulispora (IFO 8187) was solvent winterized in order to raise the content of γ-linolenic acid (GLA). Effects of winterization conditions (solvent, oil concentration in the solvent and temperature) and changes of glyceride compositions were discussed. The fungal oil was separated into four diglycerides and 17 triglycerides (TG) with high performance liquid chromatography. The predominant species were POO, POP and LOP, whose contents were 24.4, 22.9 and 9.4% of the total TG, respectively. Ethanol at 4°C gave the highest GLA content of 10.5% in spite of lower yield than with acetone at −20°C. The highest separation efficiency for GLA (ηGLA) was 0.27 with acetone at −20°C and 10% oil concentration, resulting in 8.3% of GLA from the fungal oil at 5.7% LGA. In case of lower oil concentration at 5–20%, ηGLA showed higher in the following order: acetone (−20°C)>n-hexane (−20°C)>acetone (4°C)>petroleum ether (−20°C). The winterization process also proved to be effective for the separation of TG type, Sa2U (Sa; saturated fatty acid; U, unsaturated fatty acid) into the crystallized fraction and SaU2 into the liquid fraction. Acetone at −20°C showed higher separation efficiency for triunsaturated TG than the other solvents.

Oxidation of isopropanol and acetone adsorbed on TiO2 under plasma generated ozone flow: Gas phase and adsorbed species monitoring

Abstract: The regeneration of isopropanol (IPA) and/or acetone saturated TiO2 surface by ozone is investigated TiO2 catalyst is placed downstream a dielectric barrier discharge and is subsequently exposed to ozone considered as the main oxidative species generated by non-thermal plasma and able to interact with the material surface at room temperature The oxidation of isopropanol and/or acetone is monitored using two parallel and complementary infrared diagnostics: (1) Fourier Transform Infrared Spectroscopy for the analysis of the gas phase composition; and (2) Diffuse Reflectance Infrared Fourier Transform Spectroscopy for the in situ analysis of the adsorbent/catalyst surface In this study, the pollutant is first adsorbed on the TiO2 surface, the plasma being switched off The irreversibly adsorbed amounts of isopropanol and acetone have been respectively quantified as 53 μmol/m2 and 19 μmol/m2 In a second step, the plasma is switched on to regenerate the surface by mineralization of the adsorbed organic species A 70-min plasma phase, with approximately 20 ppm of ozone constantly flowing through the adsorbent bed yields 85 nmol and 89 nmol of CO2 per injected joule of energy for isopropanol and acetone saturated surfaces, respectively Acetone has been evidenced as the main oxidation intermediate of isopropanol on TiO2 surface It has been proven that the complete oxidation of isopropanol and acetone is mainly limited by the acetone oxidation rate Competitive adsorption on the surface of the catalyst between both compounds has been studied Results obtained are compared with those observed in the photocatalytic oxidation of the same species