Topic
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.
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01 Dec 1982
TL;DR: When Clostridium acetobutylicum was grown in continuous culture under phosphate limitation, glucose was fermented to butanol, acetone and ethanol as the major products, and on the basis of these results a two-stage continuous process was developed in which 87.5% of the glucose was converted into butanol and acetone.
Abstract: When Clostridium acetobutylicum was grown in continuous culture under phosphate limitation (0.74 mM) at a pH of 4.3, glucose was fermented to butanol, acetone and ethanol as the major products. At a dilution rate of D=0.025 h−1 and a glucose concentration of 300 mM, the maximal butanol and acetone concentrations were 130 mM and 74 mM, respectively. 20% of the glucose remained in the medium. On the basis of these results a two-stage continuous process was developed in which 87.5% of the glucose was converted into butanol, acetone and ethanol. The cells and minor amounts of acetate and butyrate accounted for the remaining 12.5% of the substrate. The first stage was run at D=0.125 h−1 and 37° C and the second stage at D=0.04 h−1 and 33° C. High yields of butanol and acetone were also obtained in batch culture under phosphate limitation.
188 citations
TL;DR: In this article, three different mixed-oxides catalysts (Mg-Zr, Mg-Al and Ca−Zr with different basic sites distribution) were studied, their activity and selectivity being correlated with their physico-chemical properties.
Abstract: Catalytic aqueous-phase aldol-condensation of acetone and furfural has been studied in this work. Three different mixed-oxides catalysts (Mg–Zr, Mg–Al and Ca–Zr, with different basic sites distribution) were studied, their activity and selectivity being correlated with their physico-chemical properties. Catalysts with the highest concentration of basic sites (especially medium-strength basic sites) are the most active and selective for the C13 fraction, whereas molar ratios of 1:1 yield the highest selectivities for C13 fraction (more than 60% atomic yield for the Mg–Zr mixed oxide). Concerning to reaction mechanism, cis isomers are the first ones formed, whereas trans isomers are the most abundant at higher reaction times. The main causes of catalysts deactivation are the modification of the physico-chemical properties of catalysts – because of the interaction with water – and in minor extent, the leaching effect; although homogeneous catalytic effects are discarded at studied conditions. The products formed, and the kinetic dependence on reactant concentration, are consistent with a catalytic mechanism in which the rate-determining step is the formation of the enolate species. The model considers consecutive reversible reactions yielding C8, in the first step, and C13, in the second step; with a first-order dependence on the species with α-hydrogen (acetone and C8), and zero-th order on those species without it (furfural and C13).
186 citations
TL;DR: The effect of different solvents on the extraction of some phenolic compounds from grape seeds was investigated in this article, where the main compounds identified by high performance liquid chromatography were gallic acid, (+)-catechin, (-)-epicatechin, the dimeric procyanidins B1 and B2, the trimeric procyclanidin C1 and epicatechin gallate.
Abstract: The effect of different solvents on the extraction of some phenolic compounds from grape seeds was investigated. The main compounds identified by high performance liquid chromatography were gallic acid, (+)-catechin, (-)-epicatechin, the dimeric procyanidins B1 and B2, the trimeric procyanidin C1 and epicatechin gallate. The solvents tested were water, absolute ethanol, 75% ethanol, acetone, 70% acetone, methanol, n-butanol, diethyl ether, ethyl acetate and a combination of diethyl ether followed by ethyl acetate. Results showed that methanol was the best solvent for the extraction of (+)-catechin, (-)-epicatechin and epigallocatechin, whereas 70% acetone yielded the largest amounts of procyanidins and 75% ethanol yielded the largest amount of gallic acid. The greatest amount of total phenols was extracted by 70% acetone.
185 citations
184 citations
TL;DR: In this paper, the catalytic performance of metallic monoliths with anodised aluminium foils was investigated in complete oxidation of volatile organic compound (VOC) mixtures.
Abstract: Pt impregnated metallic monoliths prepared from anodised aluminium foils were tested to study their catalytic activity in complete oxidation of volatile organic compound (VOC) mixtures. The VOCs oxidised were 2-propanol, toluene, methyl ethyl ketone (MEK), acetone and their mixtures. Complete oxidation was obtained in all cases except for the case of 2-propanol, where acetone was found as an oxidation intermediate. Even if the adsorption of the VOC on the Al 2 O 3 is governed by its polarity, the reactivity is mainly affected by the competition of the oxygen atoms chemisorbed on the Pt particles.
184 citations