Showing papers on "Acetone published in 1996"
TL;DR: In this paper, the degradation of acetone was carried out in a UV reactor in the presence of ∼16 mM H2O2 such that most of the UV was absorbed by H 2O2.
Abstract: Acetone is a significant pollutant in contaminated groundwaters and industrial effluents. It can be treated by the UV/H2O2 process but only slowly. This study aims to understand the degradation mechanism and hence the reasons for slow treatment. The degradation of acetone was carried out in a UV reactor in the presence of ∼16 mM H2O2 such that most of the UV was absorbed by H2O2. The decay of acetone was followed by gas chromatography, and the generation of intermediates (identified as acetic, formic, and oxalic acids) was followed by ion chromatography. Measurement of the total organic carbon indicated a complete carbon balance throughout the reaction ending in mineralization. A kinetic model, based on an assumed mechanism, was developed that generated a profile of reactants and intermediates in agreement with the experimental data, including the pH profile. The initial concentrations of acetone and hydrogen peroxide strongly affect the initial rate of acetone degradation, but no pH effect was observed i...
257 citations
TL;DR: In this article, a silicalite zeolite membrane supported on the inner surface of a porous stainless-steel cylindrical tube was used to separate organic and water mixtures.
219 citations
TL;DR: From size exclusion chromatography (SEC) it was shown that degradation occurred during film processing, in agreement with the acid-catalyzed degradation of polyesters, and that the mechanism of degradation greatly depended on the content in the oligomers.
Abstract: Biodegradable films were prepared by casting acetone solutions of mixtures of a high molecular weight poly(DL-lactic acid) (HMW-PLA50) with 0, 10, and 30% w/w poly(DL-lactic acid) oligomers (LMW-PLA50), before drying. From size exclusion chromatography (SEC) it was shown that degradation occurred during film processing, in agreement with the acid-catalyzed degradation of polyesters. The higher the content of LMW-PLA50, the larger the decrease of the molar masses. The three selected film formulations were then allowed to age in isoosmolar 0.13M, pH 7.4 sodium phosphate buffer at 37 degrees C. The hydrolytic degradation was monitored by using various techniques, namely weighing to quantify water absorption and weight loss, SEC to evaluate molar mass changes, head space gas chromatography to assess the desorption of residual acetone, and enzymatic assay of the L-lactic acid released in the aging media. The presence of LMW-PLA50 clearly accelerated film degradation. Moreover, it was shown that the mechanism of degradation greatly depended on the content in the oligomers.
132 citations
TL;DR: In this paper, a modified Heller equation (Heller, 1965) was used to predict ternary excess properties from the values of corresponding three binary mixtures involved and compared with the experimental values of the physical properties.
103 citations
TL;DR: Aromatic ketones, β-keto esters, and simple aliphatic ketone were reduced with excellent selectivity to the corresponding (S)-alcohols by using the acetone powder of Geotrichum candidum as discussed by the authors.
87 citations
TL;DR: In this article, it was shown that acetone and acetonitrile probably coordinate strongly with Sn4+ centers preventing the solvolysis of the SiOSn units and the formation of peroxo intermediate.
Abstract: Tin-silicalite-1 (MFI) prepared by hydrothermal synthesis has been used as catalyst in the hydroxylation of phenol with aqueous H2O2. Isolated Sn4+ ions which are probably attached to the defect silanols are active in this reaction. At optimum conditions, a H2O2 efficiency of 70% and a ortho to para product ratio of 1.6 have been achieved. The solvent used has a strong influence on the activity. The UV-Vis spectral studies indicate that acetone and acetonitrile probably coordinate strongly with Sn4+ centers preventing the solvolysis of the SiOSn units and the formation of peroxo intermediate. Methanol probably causes the cleavage of SiOSn bond to form SiOH and SnOMe species. Water was found to be an efficient solvent. The formation of EPR active radical ion in presence of H2O2 and H2O and its attenuation in presence of acetone, acetonitrile and methanol support the above conclusion.
81 citations
TL;DR: In this article, a polymer prepolymer was divided into two parts and to one of them acetone was added, and the prepolymers were then dispersed in water followed by chain extension with hydrazine producing dispersions with a 35% (w/w) solid content.
74 citations
TL;DR: In this article, the infrared absorption spectra of acetone and methanol mixtures have been investigated in a solid argon matrix at 9 K. The most stable structure calculated was found to possess those two kinds of H-bonds, assuming a planar six-membered ring-like structure.
Abstract: The infrared absorption spectra of acetone and methanol mixtures have been investigated in a solid argon matrix at 9 K. A number of intramolecular complex bands were observed both in the acetone and methanol fundamental regions. From the concentration dependence of the infrared spectral pattern, acetone and methanol seemed to form a 1:1 binary complex. Noticeable red-shifts of the CO stretching mode of acetone as well as the OH stretching mode of methanol suggest that the two molecules are bound mainly through a H-bond between the carbonyl oxygen and the hydroxyl hydrogen atoms. A relatively weaker H-bonded interaction appeared also to act between the oxygen atom of methanol and a hydrogen atom of acetone. This view was found to be consistent with ab initio SCF, MP2, and DFT level computations. The most stable structure calculated was found to possess those two kinds of H-bonds, assuming a planar six-membered ring-like structure.
63 citations
TL;DR: In this article, the peroxidases were incubated in vitro with anthracene as a substrate, and it was shown that the presence of acetone was essential for the elimination of anthracenes and concomitant formation of anthraquinone.
60 citations
TL;DR: In this article, the state of copper-containing compounds in a hydrogen medium at 200-400°C and the nature of their interaction with the reaction components were studied, and the mechanism for the synthesis of methanol from CO and CO2 and for the hydrogenation of acetone to isopropanol were discussed.
Abstract: Mechanisms for the synthesis of methanol from CO and CO2 and for the hydrogenation of acetone to isopropanol are discussed based on the recent experimental results obtained by the authors. The state of copper-containing compounds in a hydrogen medium at 200–400°C and the nature of their interaction with the reaction components were studied. Hydrogenation of carbon oxides and acetone was proposed to be the result of the ability of copper ions to reversible transformations to generate copper metal and protons. Activation of acetone and CO2 can be achieved through their interaction with Cu0, and activation of CO through its interaction with oxygen-containing sites of Cu+1OCu+1 type which are formed after oxidation of a portion of Cu0 with carbon dioxide.
60 citations
TL;DR: In this paper, the co-precipitation of Ni/Al2O3 catalysts has been used to synthesize methyl isobutyl ketone (MIBK) or 2-propanol.
Abstract: Ni/Al2O3 catalysts have been prepared by the co-precipitation method and have been studied for acetone hydrogenation at atmospheric pressure in the temperature region 373–473 K. Effects of metal content, reaction temperature and flow rate of the feed on the conversion and product selectivity are reported. It is possible to selectively synthesize methyl isobutyl ketone (MIBK) or 2-propanol by varying experimental conditions. More than 95% selectivity towards MIBK is reported on 10 wt.-% Ni/Al2O3 catalyst at 373 K and at 1 atmosphere.
TL;DR: With the exception of Co on both surfaces, and Ni and Cu in ethanol for Sil-dmu, the variation in enthalpy of all solvent-solute interactions on these silicas is exothermic in nature.
Patent•
28 Jun 1996TL;DR: In this article, the present invention relates to a process for separating polyhydroxyalkanoate (PHA) from a biomass, the process comprising extracting the polyHOGO with at least one PHA solvent selected from the group consisting of acetone, acetonitrile, benzene, butyl acetate and butyl propionate.
Abstract: The present invention relates to a process for separating polyhydroxyalkanoate from a biomass, the process comprising extracting the polyhydroxyalkanoate with at least one PHA solvent selected from the group consisting of acetone, acetonitrile, benzene, butyl acetate, butyl propionate, β-butyrolactone, γ-butyrolactone, diethyl carbonate, diethylformamide, dimethyl carbonate, dimethyl succinate, dimethyl sulfoxide, dimethylformamide, ethyl acetate, ethylene glycol diacetate, methyl acetate, methyl ethyl ketone, 1,4-dioxane, tetrahydrofuran, toluene, xylene, and mixtures thereof.
TL;DR: The catalytic potential of zeolite H-beta in the hydration and isomerization of α-pinene was investigated in this paper, where the main product is the monocyclic alcohol α-terpineol (48%) though selectivity towards bicyclic terpenes is higher than observed for sulphuric acid (26% vs 5.5%).
Abstract: The catalytic potential of zeolite H-beta in the hydration and isomerization of α-pinene was investigated. In the presence of water the main product is the monocyclic alcohol α-terpineol (48%) though selectivity towards bicyclic terpenes is higher than observed for sulphuric acid (26% vs. 5.5%). When the isomerization is performed in pure acetone, a new compound forms by a novel C C coupling reaction between α-pinene and acetone. The product is identified as α-terpinyl acetone. This coupling seems to be a general reaction between α-pinene and ketones and is catalyzed exclusively by zeolite beta.
Patent•
22 Oct 1996
TL;DR: In this paper, the authors used a silicalite, silicalitic filled polymer membrane and process for the selective removal of acetone and butanol from Clostridium acetobutylicum fermentation media.
Abstract: Silicalite, silicalite filled polymer membrane, and process for the selective adsorption of acetone and butanol from aqueous solutions thereof. The silicalite, silicalite filled polymer membrane, and process are particularly suited to the removal of acetone and butanol from Clostridium acetobutylicum fermentation media in that the membrane is not fouled by the fermentation media and may be used without removing the cells from the fermentation media. The silicalite and silicalite filled polymer membrane show excellent selectivity to the adsorption of acetone and butanol relative to the ethanol, acetic acid, and butyric acid components of the fermentation media.
TL;DR: Together, these studies provide the first demonstration of a CO2-dependent pathway of acetone metabolism for a strictly aerobic bacterium and provide direct evidence for the involvement of an ATP-dependent carboxylase in bacterial acet one metabolism.
Abstract: The metabolism of acetone by the aerobic bacterium Xanthobacter strain Py2 was investigated. Cell suspensions of Xanthobacter strain Py2 grown with propylene or glucose as carbon sources were unable to metabolize acetone. The addition of acetone to cultures grown with propylene or glucose resulted in a time-dependent increase in acetone-degrading activity. The degradation of acetone by these cultures was prevented by the addition of rifampin and chloramphenicol, demonstrating that new protein synthesis was required for the induction of acetone-degrading activity. In vivo and in vitro studies of acetone-grown Xanthobacter strain Py2 revealed a CO2-dependent pathway of acetone metabolism for this bacterium. The depletion of CO2 from cultures grown with acetone, but not glucose or n-propanol, prevented bacterial growth. The degradation of acetone by whole-cell suspensions of acetone-grown cells was stimulated by the addition of CO2 and was prevented by the depletion of CO2. The degradation of acetone by acetone-grown cell suspensions supported the fixation of 14CO2 into acid-stable products, while the degradation of glucose or beta-hydroxybutyrate did not. Cultures grown with acetone in a nitrogen-deficient medium supplemented with NaH13CO3 specifically incorporated 13C-label into the C-1 (major labeled position) and C-3 (minor labeled position) carbon atoms of the endogenous storage compound poly-beta-hydroxybutyrate. Cell extracts prepared from acetone-grown cells catalyzed the CO2- and ATP-dependent carboxylation of acetone to form acetoacetate as a stoichiometric product. ADP or AMP were incapable of supporting acetone carboxylation in cell extracts. The sustained carboxylation of acetone in cell extracts required the addition of an ATP-regenerating system consisting of phosphocreatine and creatine kinase, suggesting that the carboxylation of acetone is coupled to ATP hydrolysis. Together, these studies provide the first demonstration of a CO2-dependent pathway of acetone metabolism for a strictly aerobic bacterium and provide direct evidence for the involvement of an ATP-dependent carboxylase in bacterial acetone metabolism.
TL;DR: The time courses of acetoacetate and beta-hydroxybutyrate formaton indicate that aceto acetate is the primary product of propylene oxide carboxylation and that beta-Hydroxy butyrate is a secondary product formed by the reduction of acetOacetate.
Abstract: A novel enzymatic reaction involved in the metabolism of aliphatic epoxides by Xanthobacter strain Py2 is described. Cell extracts catalyzed the CO2-dependent carboxylation of propylene oxide (epoxypropane) to form acetoacetate and beta-hydroxybutyrate. The time courses of acetoacetate and beta-hydroxybutyrate formaton indicate that acetoacetate is the primary product of propylene oxide carboxylation and that beta-hydroxybutyrate is a secondary product formed by the reduction of acetoacetate. Analogous C5 carboxylation products were identified with 1,2-epoxybutane as the substrate. In the absence of CO2, propylene oxide and 1,2-epoxybutane were isomerized to form acetone and methyl ethyl ketone, respectively, as dead-end products. The carboxylation of short-chain epoxides to beta-keto acids is proposed to serve as the physiological reaction for the metabolism of aliphatic epoxides in Xanthobacter strain Py2.
TL;DR: In this paper, the one-step synthesis of methyl isobutyl ketone from acetone and hydrogen was investigated by using Pd/Nb2O5· nH2O catalyst.
TL;DR: T-Butanol and methyl ethyl ketone were well resolved from ethanol, acetone, methanol and other commonly observed putrefactive volatiles using direct injection or headspace analysis and avoids the possibility of error in the quantitation of ethanol due to the presence of n-propanol.
TL;DR: In this paper, the principal components of the carbonyl carbon chemical shift tensor of the hydrogen-bonded 1:1 stoichiometric acetone−H−ZSM-5 adsorption complex have been determined from an analysis of 13C NMR spectra of static and magic angle sample spinning powder samples at 78 and 130 K, respectively.
Abstract: The principal components of the carbonyl carbon chemical shift tensor of the hydrogen-bonded 1:1 stoichiometric acetone−H−ZSM-5 adsorption complex have been determined from an analysis of 13C NMR spectra of static and magic angle sample spinning powder samples at 78 and 130 K, respectively. In a similar manner the principal elements of this tensor have been determined for physisorbed acetone in silicalite and the pure solid in order to separate changes due to hydrogen bonding of the acetone molecule in the zeolite complex from confinement effects defined as interactions of the adsorbed molecule with the siliceous cavity. The energetics associated with such changes have also been measured using microcalorimetry. The differential heats of adsorption of acetone adsorbed in H−ZSM-5 and silicalite over a wide range of surface coverage are reported. The results are compared with ab-initio calculations of the reaction of acetone with model zeolite structures to form a stoichiometric hydrogen-bonded cluster−molec...
TL;DR: In this paper, the first-order kinetics for the destruction of both isopropyl alcohol and acetone were determined from fits of the experimental data, assuming Arrhenius behavior.
Abstract: The oxidation of isopropyl alcohol in supercritical water has been investigated using Raman spectroscopy. Results for species concentration as a function of residence-time are presented for temperatures ranging from 400 to 480 °C at constant pressure, 24.4 ± 0.3 MPa, and constant equivalence ratio, 0.88 ± 0.02. Acetone has been identified as the principal intermediate formed and subsequently destroyed, during the oxidation process. By assuming first-order kinetics for the destruction of both isopropyl alcohol and acetone, effective first-order rate constants have been determined from fits of the experimental data. Assuming Arrhenius behavior, the fits yield rate constants for isopropyl alcohol, keff,ipa = 3.255 × 1022(s-1) exp[−301.1(kJ·mol-1)/RT], and for acetone, keff,ace = 1.948 × 1010(s-1) exp[−137.7(kJ·mol-1)/RT]. These results indicate that for temperatures greater than 425 °C, the destruction of isopropyl alcohol proceeds faster than that of acetone.
TL;DR: In this paper, a bipolar radioactive charger was used to irradiate air which contained acetone vapour within a wide range of concentrations (∼ 100-300,000 ppm) and the mobility distributions of both positive and negative cluster ions in acetone rich air were studied.
TL;DR: Acetone-butanol fermentation by Clostridium aurantibutyricum ATCC 17777 utilizing a model medium for palm oil mill effluent (POME) was investigated and resulted in a reasonable oil hydrolysis rate between those obtained in cultures with constant pHs of 6.2 or 5.5, and higher solvent productivities than in either of the single-pH cultures.
Patent•
19 Jan 1996
TL;DR: In this article, a cellulose acetate solution has celluloseacetate in a solvent and the solvent is an ether, the ketone, the ester, or an alcohol having 1 to 6 carbon atoms.
Abstract: A cellulose acetate solution has cellulose acetate in a solvent. The cellulose acetate has an average acetic acid content in the range of 58.0 to 62.5%. In the first embodiment of the invention, the solvent is a mixture of acetone and another organic solvent. The organic solvent is an ether having 3 to 12 carbon atoms, a ketone having 4 to 12 carbon atom, an ester having 3 to 12 carbon atoms, or an alcohol having 1 to 6 carbon atoms. In the second embodiment, the solvent is the ether, the ketone or the ester. Processes for the preparation of the solution and a cellulose acetate film are also disclosed.
TL;DR: In this article, complete oxidation of solvents (e.g., acetone, butyl acetate and isopropanol) over base metal oxides was investigated using a fixed bed reactor.
TL;DR: The thermal and chemical stability of a titanium-substituted MCM-41 with 39 Si/Ti mole ratio of 39 and pore diameter of 2.4 nm was studied with small-angle X-ray diffraction and Xray absorption near-edge structure techniques as discussed by the authors.
Abstract: The thermal and chemical stability of a titanium-substituted MCM-41 (TiMCM-41) with Si/Ti mole ratio of 39 and pore diameter of 2.4 nm was studied with the small-angle X-ray diffraction and X-ray absorption near-edge structure techniques. The TiMCM-41 was stable in helium flow below 1273 K and under gas-phase reaction conditions of ethanol dehydrogenation (ethanol/ O2 = 1 mol/mol, 373–723 K). Under liquid-phase reaction conditions of phenol hydroxylation (phenol/35% H2O2 /acetone in moles=3∶1∶7,333K), however, it lost the MCM-41structure and titanium was leached out of the silicalite framework.
TL;DR: In this paper, a high-selective one-step synthesis of methyl isobutyl ketone (MIBK) from acetone and hydrogen at 200°C and 1 atm has been developed utilizing magnesia-supported palladium catalysts.
Abstract: Highly selective one-step synthesis of methyl isobutyl ketone (MIBK) from acetone and hydrogen at 200°C and 1 atm has been developed utilizing magnesia-supported palladium catalysts. Sodium vapor deposition on magnesia followed by impregnation with tetraamine palladium (II) chloride apparently enhances the catalyst basicity as compared with that of magnesia supported palladium, resulting in a great increase of both acetone conversion and MIBK yield. Such a catalyst exhibits good stability, high activity and MIBK selectivity; it gives 47–64% conversion, 50–65% MIBK selectivity and 31–33% MIBK yield during a period of 8 h on stream.
TL;DR: In this paper, an Enzymatic oxidative polymerization of 4,4′-biphenyldiol was performed in an aqueous organic solvent using horseradish peroxidase as catalyst.
Abstract: Enzymatic oxidative polymerization of 4,4′-biphenyldiol was performed in an aqueous organic solvent using horseradish peroxidase as catalyst. In the polymerization using a mixture of 1,4-dioxane and phosphate buffer (pH 7.0) (80:20 vol-%) as solvent, the monomer was quantitatively consumed to give powdery polymeric materials in a high yield. The resulting polymer is soluble in polar solvents such as N,N-dimethylformamide, dimethyl sulfoxide, and acetone. The molecular weight of the methylated product is 7.3 × 103. The polymer exhibits high thermal stability under nitrogen.
TL;DR: In this article, an activated carbon obtained by activation of olive stones in carbon dioxide at 1113 K has been used in a study where the spent activated carbon samples were regenerated by means of organic solvent treatments and subsequent heat treatments.
Abstract: An activated carbon obtained by activation of olive stones in carbon dioxide at 1113 K has been used in this study. This was saturated with o-chlorophenol and m-chlorophenol from their corresponding aqueous solutions. The spent activated carbon samples were regenerated by means of organic solvent treatments and subsequent heat treatments. The organic solvents used were: acetone, methanol, ethanol and benzene. The extent of the chemical regeneration in these systems is a function of the strength of the adsorbent–adsorbate interactions. When the systems are treated with organic solvents the adsorbate extracted mainly comes from the physisorbed fraction. When the samples extracted with organic solvents are thermally regenerated by heating at 1073 K in an inert flow, in most of the cases, the amount of adsorbate removed increased in comparison to treatments without solvents. A part of the physisorbed fraction remaining in these samples after the solvent treatments is released at lower temperatures than the chemisorbed fraction. During the heat treatment, part of the physisorbed fraction is transformed to a chemisorbed one which has a greater desorption energy than the former.
Patent•
16 Aug 1996TL;DR: In this article, the present invention relates to a process for separating polyhydroxyalkanoate (PHA) from a biomass, the process comprising extracting the polyHOGO with at least one PHA solvent selected from the group consisting of acetone, acetonitrile, benzene, butyl acetate and butyl propionate, β-butyrolactone.
Abstract: The present invention relates to a process for separating polyhydroxyalkanoate from a biomass, the process comprising extracting the polyhydroxyalkanoate with at least one PHA solvent selected from the group consisting of acetone, acetonitrile, benzene, butyl acetate, butyl propionate, β-butyrolactone, η-butyrolactone, diethyl carbonate, diethylformamide, dimethyl carbonate, dimethyl succinate, dimethyl sulfoxide, dimethylformamide, ethyl acetate, ethylene glycol diacetate, methyl acetate, methyl ethyl ketone, 1,4-dioxane, tetrahydrofuran, toluene, xylene, and mixtures thereof.