Showing papers on "Acetone published in 2011"
TL;DR: In this paper, the authors investigated the chemical regeneration of activated carbon presaturated with two different dyestuffs by various organic solvents, redox agents, acids, and bases using batch and column experiments.
Abstract: Adsorption by activated carbon is widely used to remove organic pollutants from waters and wastewaters. However, the economical competitiveness of the activated adsorption process depends upon the reusability of exhausted carbon. This study investigated the chemical regeneration of activated carbon presaturated with two different dyestuffs by various organic solvents, redox agents, acids, and bases using batch and column experiments. From the batch desorption test results, 60% acetone in water and 40% isopropanol in water were found to be the optimal regenerants for the red and yellow dyes, respectively. A higher desorption temperature could improve the dye desorption efficiencies using acetone and isopropanol. The column test results showed that the carbon bed adsorption capacity decreased dramatically but seemed to be stabilized after 3 repeated adsorption/desorption cycles.
153 citations
TL;DR: In this paper, the aldol condensation reactions of furfural/hydroxymethylfurfural (furfurals) with acetone/propanal in water-methanol solvents were studied over the solid base catalysts MgO-ZrO 2, NaY and nitrogen-substituted NaY (Nit-NaY).
Abstract: The aldol condensation reactions of furfural/hydroxymethylfurfural (furfurals) with acetone/propanal in water–methanol solvents were studied over the solid base catalysts MgO–ZrO 2 , NaY and nitrogen-substituted NaY (Nit-NaY). The reactions were conducted at 120 °C and 750 psig of He in batch reactors. Nit-NaY exhibited catalytic activity for aldol condensation comparable to MgO–ZrO 2 and much higher than that of NaY, indicative of the increased base strength after replacing the bridging oxygen with the lower electronegativity nitrogen over Nit-NaY. The aldol condensation of furfurals with acetone produces two different products, the monomer and the dimer. The monomer is formed from reaction of furfurals with acetone. The dimer is formed from reaction of the monomer with furfurals. MgO–ZrO 2 had a higher selectivity towards dimer formation. In contrast, Nit-NaY was more selective towards the monomer product due to the cage size in the FAU structure, indicating that Nit-NaY is a shape selective base catalyst. Increasing the water concentration in the feed solution or increasing the feed concentration led to both increased catalytic activity and dimer selectivity. The Nit-NaY catalyst was not stable and lost catalytic activity when recycled due to leaching of the framework nitrogen. Different characterization techniques, including XRD, high resolution Ar adsorption isotherm, basic sites titration, CO 2 TPD-MS, TGA and 29 Si SP MAS NMR, were used here to characterize the fresh and spent catalysts. The results show that Nit-NaY maintains only part of the FAU-type crystal structure. Furthermore, the base strength over Nit-NaY was found to be between that of Mg 2+ –O 2− pair and Mg(OH) 2 . The reaction mechanism over Nit-NaY was discussed.
148 citations
TL;DR: The morphology and porous structure of cellulose acetate (CA) fibers were highly dependent on the dichloromethane(DCM)/acetone ratio and the concentration of the solutions.
123 citations
TL;DR: In this paper, the effect of crystal size on catalytic activity and stability of nano-sized ZSM-5 zeolites was investigated for light olefins synthesis from acetone.
Abstract: Production of light olefins such as ethylene, propylene and isobutylene from acetone was examined over ZSM-5 zeolites. These light olefins are produced from acetone over the acid sites of the zeolite via a series of consecutive reactions where olefins such as ethylene and propylene are obtained by cracking of isobutylene produced from aldol condensation products of acetone. Macro- and nano-sized ZSM-5 zeolites were prepared by conventional hydrothermal and emulsion methods, respectively, and the ZSM-5 zeolites with nearly the same acidity and BET surface area were obtained regardless of the crystal sizes. From SEM observations, the crystal sizes of the zeolites were approximately 2000 nm and 30–40 nm. These zeolites with different crystal sizes were applied to light olefins synthesis from acetone, and the effect of crystal size on catalytic activity and stability was investigated. As compared with the macro-seized zeolite, the nano-sized zeolite exhibited a high activity over a long lifetime. However, because the nano-sized zeolite possesses a large external surface area, undesirable reactions to form aromatics from the produced light olefins occurred on the acid sites located near the external surface. To inhibit aromatics formation, selective deactivation of the acid sites located near the outer surface of the zeolite was achieved via the catalytic cracking of silane (CCS) method using diphenyl silane (DP-silane). The CCS method was effective in deactivating the acid sites located near the external surface of the ZSM-5 zeolite. Moreover, the nano-size zeolite after the CCS treatment using DP-silane exhibited high olefins and low aromatics yields under high acetone conversion conditions.
110 citations
TL;DR: In this article, the effects of different factors on the separation of acetone, butanol, and ethanol from ABE-water solutions by pervaporation with silicalite-l/polydimethylsiloxane (PDMS) hybrid membranes were investigated.
110 citations
TL;DR: The mixture acetone/acetic acid (99:1, v/v) gave the best results for the qualitative and quantitative assay of the polyphenols present in strawberries since all 28 compounds were detected only in these extracts in quantities higher or comparable to the other extraction solvents tested.
Abstract: Eight different solvent mixtures containing acetone or methanol pure or combined with an acid (acetic, formic, hydrochloric) were tested for their efficiency for extraction of phenolic compounds from strawberries belonging to five groups of polyphenols: anthocyanins, flavonols, flavan-3-ols, hydroxycinnamic acid derivatives and conjugated forms of ellagic acid. Twenty-eight compounds from these five groups have been detected and quantified using HPLC–DAD–ESI-MSn. The yield of each phenolic compound and group was evaluated with regard to the extraction solvent composition. Acetone containing extraction mixtures were superior to the ones containing methanol for extraction yield of total phenolic compounds, which was especially pronounced for the groups of flavan-3-ols and conjugated forms of ellagic acid. The mixture acetone/acetic acid (99:1, v/v) gave the best results for the qualitative and quantitative assay of the polyphenols present in strawberries since all 28 compounds were detected only in these ex...
97 citations
TL;DR: A novel copper-catalyzed cyanation of aryl and heteroaryl bromides using acetone cyanohydrin has been developed.
Abstract: A novel copper-catalyzed cyanation of aryl and heteroaryl bromides using acetone cyanohydrin has been developed.
91 citations
TL;DR: The obtained results showed that the chemical properties of the oil product were significantly affected by the type of solvent used for the solvolysis process, which is the highest among the oil products produced using different solvents.
87 citations
TL;DR: Oxidative methyl esterification of primary alcohols and diols with methanol was successfully achieved, using acetone as a hydrogen acceptor, under the influence of an iridium complex combined with 2-(methylamino)ethanol (MAE) as catalyst.
Abstract: Oxidative methyl esterification of primary alcohols and diols with methanol was successfully achieved, using acetone as a hydrogen acceptor, under the influence of an iridium complex combined with 2-(methylamino)ethanol (MAE) as catalyst.
87 citations
TL;DR: In this paper, the performance of a hydrotalcite-derived mixed oxide (Mg3AlOx) for three different aldolization reactions, concerned with the valorisation of biomass derivatives, has been studied.
80 citations
TL;DR: In this article, a membrane-based method using nanofiltration (NF) membranes is presented to extract edible oil from soybean oil/solvent mixtures at various separation pressures and constant temperature in a dead-end filtration set up.
Abstract: The extraction stage of edible oil in the oil industry is commonly performed by using toxic solvents (e.g. hexane) and processes with high energy consumption (e.g. distillation, evaporation) to recover the solvent, which represents around 70–75 wt% in the oil–solvent mixture. In this paper, a membrane-based extraction method using nanofiltration (NF) membranes is presented. Commercial nanofiltration membranes made of different polymers (Desal-DK-polyamide NF from GE-osmonics®, NF30 polyethersulfone NF from Nadir®, STARMEMTM122 polyimide from MET® and SOLSEP NF030306 silicone base polymer SOLESP®) were selected and tested to recover the solvent from soybean oil/solvent (10–20–30% w/w oil) mixtures at various separation pressures and constant temperature in a dead-end filtration set up. The selection of the solvent was made in order to compare solvents obtainable from renewable resources, such as ethanol, iso-propanol and acetone, with solvents traditionally used in the industry (i.e. cyclohexane and n-hexane). The structural stability of the membranes towards the different solvents used in this work was verified visually, by the variation of the membrane area and by means of permeate flux assessments. Desal-DK and NF30 showed poor filtration performance and even visible defects after exposure to acetone but a good performance was obtained for the nanofiltration membranes STARMEMTM122 and SOLSEP NF030306 with ethanol, iso-propanol and acetone. For example, considering a mixture with 30% edible oil in acetone, STARMEMTM122 shows a flux and oil rejection of 16.8 L m−2 h and 70%, respectively. For the same conditions, SOLSEP NF030306 exhibited a flux of 4.8 L m−2 h with 78% rejection, which shows the potential application of nanofiltration membranes in the oil industry.
TL;DR: In this article, the acid-catalyzed reaction of glycerol with acetone was studied in the presence of impurities that might be present in the crude glycerin of biodiesel production.
Abstract: The acid-catalyzed reaction of glycerol with acetone was studied in the presence of impurities that might be present in the crude glycerin of biodiesel production. These are mainly methanol, water and sodium chloride, in different amounts. The results indicated that methanol has minor effect on the glycerol conversion, whereas the concomitant addition of water and sodium chloride produces a drastic decrease of the conversion. The nature of the acid catalyst also affects the conversion in the presence of impurities. Amberlyst-15™ acid resin is more sensible to the water content than zeolite Beta. The results of the glycerol adulteration with different contaminants were compared with the reaction using a crude glycerin from a Brazilian biodiesel industrial plant.
TL;DR: In this paper, the formation mechanism of pyrolysis gases released during the pyrolys of pectin under the conditions that simulate cigarette smouldering was investigated by thermogravimetric analysis coupled to Fourier transform infrared spectrometer (TG-FTIR).
TL;DR: In this article, a non-equilibrium and non-adiabatic model, incorporating a linear driving force model, Langmuir model for toluene and Aranovich-Donohue model for acetone, was used to simulate the dynamic behaviors of concentration and temperature during the adsorption and thermal regeneration steps.
TL;DR: In this article, a 10L, flow-through laboratory reaction chamber Inlet ozone concentrations were maintained between 150 and 200ppb (generally much lower in chamber air), relative humidity at 50%, temperature at 25°C and exposure occurred over 24h.
TL;DR: In this paper, it has been shown that zeolite catalysts exhibit high activity in the formation of the acetone ketal of glucose in a flow system with the quantitative selectivity for the 1,2-product.
Abstract: The ketalization of polyols (glycerol, xylitol, xylose) in the presence of a number of heterogeneous acid catalysts has been studied. It has been shown that zeolite catalysts exhibit high activity in the formation of the acetone ketal of glucose in a flow system with the quantitative selectivity for the 1,2-product. The best catalyst is zeolite beta; in the presence of this zeolite and excess acetone, the yield is over 90% or, in the case of the structured reactor, even greater than 98% It has been shown that zeolite-based systems catalyze the formation of ketals of xylitol and xylose with a yield of up to 50% in the presence of excess acetone.
TL;DR: In this article, waterborne polyurethane (PU) dispersions were prepared from isophorone diisocyanate (IPDI), 2-bis(hydroxymethyl) propionic acid (DMPA), 1,4-butane diol (BD), poly(propylene glycol) (PPG), and triethylamine (TEA) by means of phase inversion through the acetone process.
Abstract: Waterborne polyurethane (PU) dispersions were prepared from isophorone diisocyanate (IPDI), 2-bis(hydroxymethyl) propionic acid (DMPA), 1,4-butane diol (BD), poly(propylene glycol) (PPG), and triethylamine (TEA) by means of phase inversion through the acetone process. Changes in DMPA content, initial PU content in acetone, phase-inversion temperature, evaporation conditions, and solvent nature were found to have a great impact on dispersion properties. Using a DMPA concentration of 0.30 mmol/g(pol), stable PU dispersions could only be obtained when the initial PU content in acetone was at least 60 wt %, and phase-inversion temperature was lower than 30 degrees C. However, when increasing the PU content to 75 wt %, stable dispersions were obtained using DMPA concentrations three times lower. Finally, viscosity curves during the water addition step as well as a phase diagram were determined to understand the particle formation mechanism.
TL;DR: The phylogenetic analysis of this strain using 16S rDNA sequence revealed 99% homology with Bacillus aquimaris and the change in fatty acid profile with different solvents further elucidated the physiological adaptations of the strain to tolerate such extreme conditions.
TL;DR: In this paper, a new homogeneous method for producing biodiesel fuel (BDF), achieving a minimum emission of waste and a low consumption of energy, was developed by adding organic solvents such as acetone to a reaction mixture of oil and methanol with an alkaline catalyst.
TL;DR: In this article, the relative high temperature ignition behavior of selected C3 oxygenated hydrocarbons, propanal (propionaldehyde, PAL or CH 3 CH 2 CHO), acetone (propanone or AC), isopropanol (iPOH), and ethyl formate (EF), is studied behind reflected shock waves.
TL;DR: In this paper, a differential packed-bed tubular reactor operated at atmospheric pressure was used to obtain the kinetic data for catalytic combustion of acetone or toluene over the Cu0.13Ce0.87Oy catalyst.
TL;DR: The subsequent finding that non-enzymatic decarboxylation of acetoacetate in vitro, under conditions similar to in vivo acetone–butanol–ethanol (ABE) fermentation, produces 1.3 to 5.2 g/L acetone between pH 6.5 and 4 helps rationalize why various knock-out and knock-down strategies did not eliminate acetone production during ABE fermentation.
Abstract: Development of a butanologenic strain with high selectivity for butanol production is often proposed as a possible route for improving the economics of biobutanol production by solventogenic Clostridium species. The acetoacetate decarboxylase (aadc) gene encoding acetoacetate decarboxylase (AADC), which catalyzes the decarboxylation of acetoacetate into acetone and CO2, was successfully disrupted by homologous recombination in solventogenic Clostridium beijerinckii NCIMB 8052 to generate an aadc − mutant. Our fermentation studies revealed that this mutant produces a maximum acetone concentration of 3 g/L (in P2 medium), a value comparable to that produced by wild-type C. beijerinckii 8052. Therefore, we postulated that AADC-catalyzed decarboxylation of acetoacetate is not the sole means for acetone generation. Our subsequent finding that non-enzymatic decarboxylation of acetoacetate in vitro, under conditions similar to in vivo acetone–butanol–ethanol (ABE) fermentation, produces 1.3 to 5.2 g/L acetone between pH 6.5 and 4 helps rationalize why various knock-out and knock-down strategies designed to disrupt aadc in solventogenic Clostridium species did not eliminate acetone production during ABE fermentation. Based on these results, we discuss alternatives to enhance selectivity for butanol production.
TL;DR: The solubilities of sulfamethazine in methanol, ethanol, 1-propanol, acetone, and chloroform have been determined from 293.15 to 333.15 K by a static equilibrium method as mentioned in this paper.
TL;DR: In this paper, the pore structure of PVDFD membranes cast from mixed solvent systems at higher evaporation temperatures, i.e. 60-100°C, exhibit superior separation factors (up to 4) with reasonably high fluxes (1-4 kg/m2h) as compared to those of pure NMP system.
TL;DR: The development and optimisation of the MI-PTR/MS technique is presented as a reliable and convenient tool for analysing seawater samples for these trace gases and its potential use in improving the current understanding of the cycling of oceanic OVOCs is discussed.
TL;DR: In this article, the authors reported on the ketalization of glycerol in supercritical acetone to give solketal (4-hydroxymethyl-2,2-dimethyl-1,3-dioxolane), an oxygenated compound useful as chemical and fuel additive for gasoline, diesel and biodiesel.
Abstract: In the last few years, the increasing production of biodiesel has led to an overproduction of glycerol, the main byproduct of this industry. This paper reports on the ketalization of glycerol in supercritical acetone to give solketal (4-hydroxymethyl-2,2-dimethyl-1,3-dioxolane), an oxygenated compound useful as chemical and fuel additive for gasoline, diesel and biodiesel. The application of supercritical fluids (SCFs) in the chemical synthesis was explored to carry out reactions to obtain the above cyclic ketal. The experimental results reveal a drastic change in the reaction behavior when the critical condition of acetone is reached ( T = 508 K). Below 508 K the reaction rate of solketal production is very low, but above this temperature a rapid increase in the reaction rate is observed. Finally, the reaction rate is stabilized at 533 K and higher temperatures due to the conversion of glycerol to acrolein and polymeric products as side reactions.
TL;DR: In this paper, the authors investigated the crystallization of amorphous poly(lactic acid) (PLA) in various organic solvents, such as acetone, ethylacetate, diethylether, tetrahydrofurane, methanol, hexane, toluene, xylene, and o-dichlorobenene.
Abstract: Crystallization of amorphous poly(lactic acid) (PLA) was investigated in various organic solvents, such as acetone, ethylacetate, diethylether, tetrahydrofurane, methanol, hexane, toluene, xylene, and o-dichlorobenene. Most of the solvents, except hexane, induced crystallization of amorphous PLA. Acetone was the most effective solvent to accelerate the crystallization among the solvents used. The crystallization was induced by permeation of acetone into the amorphous phase of PLA, and the permeation obeyed Fick type diffusion. The crystallization rate increased with increasing of conducting temperature. Crystallized PLA formed α crystalline structure. The permeated acetone in the crystallized PLA gradually evaporated as time passes, and the elimination of acetone affected thermal and mechanical properties of the crystallized PLA. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
TL;DR: In this paper, two different preparation methods (co-precipitation and alcogel) and tested in furfural/acetone aldol condensation reactions were presented.
TL;DR: In this paper, the stability and activity of the low redox potential Melanocarpus albomyces laccase (MaL) in various aqueous organic (acetone, ethanol, propylene glycol, diethane glycol monomethyl ether) solvent systems was studied spectrophotometrically using 2,6-dimethoxyphenol (2.6-DMP) as substrate.
Abstract: The stability and activity of the low redox potential Melanocarpus albomyces laccase (MaL) in various aqueous organic (acetone, ethanol, propylene glycol, diethylene glycol monomethyl ether) solvent systems was studied spectrophotometrically using 2,6-dimethoxyphenol (2,6-DMP) as substrate. In addition, reactivity of the enzyme with two lignans; matairesinol (MR) and 7-hydroxymatairesinol (HMR), was examined by oxygen consumption measurements in the most potential aqueous organic solvent systems. Polymerization of the lignans by MaL was verified by matrix assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) and size exclusion chromatography (SEC). Polymerization of the higher molecular weight lignin model compound, dehydrogenation polymers (DHPs), was studied by SEC. The solubilities of industrial softwood and hardwood kraft lignins were evaluated as parameters for investigation of enzymatic modification in aqueous organic solvent systems. The functioning of MaL in different aqueous organic media was excellent. Propylene glycol and diethylene glycol monomethyl ether were better solvents than ethanol or acetone in enzymatic oxidations. Even though they were the best solvents for enzyme oxidation, ethanol and propylene glycol were selected for further tests because of their different physicochemical properties. The results obtained in this study for the use of laccase-catalysed reactions in organic solvents to improve the efficiency of lignin oxidation may be exploited in several applications and areas in which the solubility of the reactants or products is a limiting factor.
TL;DR: Observations indicate that P11 has a secondary alcohol dehydrogenase that enables it to reduce acetone to isopropanol, while P7 lacks this enzyme, which offers an opportunity for biological production of isOPropanol from acetone reduction in the presence of gaseous substrates (CO, CO2, and H2).
Abstract: Gasification-fermentation is an emerging technology for the conversion of lignocellulosic materials into biofuels and specialty chemicals. For effective utilization of producer gas by fermenting bacteria, tar compounds produced in the gasification process are often removed by wet scrubbing techniques using acetone. In a preliminary study using biomass generated producer gas scrubbed with acetone, an accumulation of acetone and subsequent isopropanol production was observed. The effect of 2 g/L acetone concentrations in the fermentation media on growth and product distributions was studied with “Clostridium ragsdalei,” also known as Clostridium strain P11 or P11, and Clostridium carboxidivorans P7 or P7. The reduction of acetone to isopropanol was possible with “C. ragsdalei,” but not with P7. In P11 this reaction occurred rapidly when acetone was added in the acidogenic phase, but was 2.5 times slower when added in the solventogenic phase. Acetone at concentrations of 2 g/L did not affect the growth of P7, but ethanol increased by 41% and acetic acid concentrations decreased by 79%. In the fermentations using P11, growth was unaffected and ethanol concentrations increased by 55% when acetone was added in the acidogenic phase. Acetic acid concentrations increased by 19% in both the treatments where acetone was added. Our observations indicate that P11 has a secondary alcohol dehydrogenase that enables it to reduce acetone to isopropanol, while P7 lacks this enzyme. P11 offers an opportunity for biological production of isopropanol from acetone reduction in the presence of gaseous substrates (CO, CO2, and H2). Biotechnol. Bioeng. 2011;108: 2330–2338. © 2011 Wiley Periodicals, Inc.