Showing papers on "Acetone published in 1994"

Organic-solvent-tolerant bacterium which secretes organic-solvent-stable lipolytic enzyme.

Abstract: A bacterial strain which could be grown in a medium containing organic solvents and which could secrete lipolytic enzyme was isolated. The stability of the lipolytic activity of the supernatant of the culture increased significantly in the presence of organic solvents such as toluene, cyclohexane, ethanol, and acetone.

Salt effects in extraction of ethanol, 1‐butanol and acetone from aqueous solutions

Abstract: Experimental studies were performed to assess the effect of salt addition on the extraction of 1-butanol, ethanol and acetone from dilute aqueous solutions using cyclopentanol, n-valeraldehyde, tert-amyl alcohol, and Adol 85NF as extractants. The liquid-liquid partitioning was examined for a few strong electrolytes in a broad range of concentrations. Results demonstrate that the distribution coefficient and selectivity in systems with reduced water activity resulting from salt addition were markedly increased. These observations can be qualitatively explained on the basis of the hydration theory. It was also determined that strong electrolytes added to the aqueous feed reduced extractant solubility in the aqueous phase, thus contributing to lower solvent losses. The results showed that the extraction efficiency was not significantly affected by increasing salt content beyond a level that reduces the water activity to a value of 0.92.

Effects of polar and nonpolar groups on the solubility of organic compounds in soil organic matter.

Abstract: Vapor sorption capacities on a high-organic-content peat, a model for soil organic matter (SOM), were determined at room temperature for the following liquids: n-hexane, 1,4-dioxane, nitroethane, acetone, acetonitrile, 1-propanol, ethanol, and methanol. The linear organic vapor sorption is in keeping with the dominance of vapor partition in peat SOM. These data and similar results of carbon tetrachloride (CT), trichloroethylene (TCE), benzene, ethylene glycol monoethyl ether (EGME), and water on the same peat from earlier studies are used to evaluate the effect of polarity on the vapor partition in SOM

Infrared evanescent-absorption spectroscopy with chalcogenide glass fibers.

Abstract: We have used telluride glass fibers fabricated in house to measure the evanescent-absorption spectra of water, methanol, ethanol, isopropanol, acetone, ethanoic acid, hexane, and chloroform. Furthermore, detection limits of less than 2 vol. % solute were obtained for mixtures of water and methanol, ethanol, isopropanol, acetone, and ethanoic acid. Techniques to reduce the detection limits are discussed.

Application of a new hydrogenated aluminophosphate oxynitride (ALPON) as a catalytic support for the one-step synthesis of methyl isobutyl ketone from acetone

Abstract: A new hydrogenated aluminophosphate oxynitride (ALPON) obtained by nitridation of AlPO4 can be used as a support to prepare a polyfunctional catalyst with both basic and metallic sites. Ni/ ALPON catalyst was effective for the low-pressure one-step methyl isobutyl ketone (MIBK) synthesis from acetone. The selectivity of the process depended on the temperature and time-on-stream of the hydrogen reduction treatment suggesting that selective MIBK production is achieved by a fine balance between basic and metallic sites.

A highly active and highly selective oxide catalyst for the conversion of ethanol to acetone in the presence of water vapour

Abstract: In the presence of water vapour and a suitable catalyst, ethanol is converted to acetone rather than to ethylene and acetaldehyde. In order to develop an appropriate catalyst for this reaction, steady-state catalytic activities and selectivities were studied for 24 oxide catalysts. It was found that the acetone selectivity is high on a catalyst having both surface acidity and basicity, suggesting that the acetone formation is an acid-base bifunctional catalytic reaction. Iron oxide is superior to the other oxides studied here in both conversion and acetone selectivity. The superiority is greatly enhanced by mixing iron oxide with zinc oxide. The preparation method for the iron–zinc mixed oxide catalyst was also studied and it was found that the optimal composition is Zn/(Fe + Zn)= 0.1–0.4 and that the optimal condition for calcination is 773 K for 3 h. The catalyst gave 100% ethanol conversion and 94% acetone selectivity at a reaction temperature of 713 K. It is initially a mixture of Fe2O3 and ZnO but is converted to a spinel type compound, ZnFe2O4, during the reaction. The optimal reaction temperature was determined to be 713 K, and at this temperature, the acetone yield decreased by 34% after a time of 24 h.

Separation of lipophilic compounds by micellar electrokinetic chromatography with organic modifiers.

Abstract: Separation of lipophilic compounds such as polyaromatic hydrocarbons (PAH) by micellar electrokinetic chromatography (MEKC) with organic modifiers was investigated. Dimethyl sulfoxide (DMSO) and acetone were used as organic modifiers, and sodium dodecyl sulfate (SDS) as a surfactant or a micelle forming reagent. By using 25 mM SDS (pH 7.0), containing 50% v/v DMSO, 8 PAHs were separated. Similarly, with 25 mM SDS, containing 30% acetone, 13 PAHs were successfully separated. For the calculation of thermodynamic quantities, critical micelle concentrations of SDS in buffers containing DMSO or acetone were measured.

Azeotropic or azeotrope-like compositions including 1,1,1,2,3,4,4,5,5,5-decafluoropentane

Abstract: Compositions of 1,1,1,2,3,4,4,5,5,5-decafluoropentane, bis(fluoromethyl) ether, 2,2,4,4-tetrafluorooxetane, 2,2,3,3-tetrafluorooxetane, 1,1,1,2-tetrafluoro-2-(fluoromethoxy)ethane, 1-(difluoromethoxy)-1,2,2-trifluoroethane, 1-(difluoromethoxy)-1,1,2-trifluoroethane, acetone, cyclopentane, ethyl acetate, ethyl formate, methyl tert-butyl ether, methyl acetate, methyl formate, propylene oxide, 2,2-dimethylbutane, n-pentane or n-propanol are useful as cleaning agents, expansion agents for polyolefins and polyurethanes, aerosol propellants, refrigerants, heat transfer media, gaseous dielectrics, fire extinguishing agents, power cycle working fluids, polymerization media, particulate removal fluids, carrier fluids, buffing abrasive agents, and displacement drying agents.

Gas/Solid Reactions with Acetone

Abstract: Gas/solid reactions of acetone vapor with neutral organic compounds, salts, or host crystals with strict exclusion of solvents are reported. This gas/solid technique largely avoids waste formation and saves resources. Starting hydrochlorides or hydrobromides are also synthesized by gas/solid techniques. Dihydrohalides of o-phenylenediamines give 1,5-benzodiazepines 3, aromatic and aliphatic 1,2-aminothiols (o-aminothiophenol, penicillamines, cysteine) yield five-membered thiazolines and thiazolidines 7, 9, 11, 13. Virtually all carbonyl reagents of the primary amino type 14 give quantitatively the imino derivatives 15 and water. Salt formation may be helpful for increasing melting points and sometimes reactivity as in 8, 10, and 12 if surface passivation has to be overcome. In the case of solid 14 the free bases react equally well. Acetone (2) may be quantitatively removed from exhaust gases by using hydroxylaminium phosphate with formation of free acetone oxime at high flow rates. Inclusion of acetone into various hosts (17-20, but not 16) is more efficient by imbibition from the gas phase than by crystallization from acetone as the solvent. This advantage may be utilized for gas separations. Some further gases (vapors) coexist in imbibed clathrates whereas others do not. The mechanisms of the gas/solid reactions are elucidated using atomic force microscopy (AFM). Phase rebuildings involve anisotropic movements of molecules over large distances and the formation of characteristic features. In some cases surface hydrates catalyze the gas/solid reaction. Solid-state mechanisms for imbibition from the gas phase into host crystals with formation of clathrates are similar in nature to those of the covalent reactions. These results are correlated with known X-ray crystal structures where available.

Isomerization and decomposition of propylene oxide. Studies with a single-pulse shock tube

Abstract: The thermal reactions of propylene oxide (1,2-epoxypropane) were studied behind reflected shocks in a pressurized driver single-pulse shock tube over the temperature range 850-1250 K and overall densities of ∼3×10 -5 mol/cm 3 . Four isomerization products, acetone, propanal, methyl vinyl ether, and allyl alcohol, and a large number of decomposition products were obtained under shock heating. The major decomposition products in decreasing order of abundance were CO, C 2 H 4 , C 2 H 6 , and CH 4 . Studies with free-radical scavengers and with isotopically labeled reactant (C 3 D 6 O) indicated that the isomerization products and ethylene retain the original skeleton of the reactant whereas all the other products involve free-radical reactions

Fermentative degradation of acetone by an enrichment culture in membrane-separated culture devices and in cell suspensions

Abstract: A mixed culture, WoAct, growing on acetone, consisted of two dominant morphotypes: a rod-shaped acetone-fermenting bacterium producing acetate, and an acetate-utilizing Methanosaeta species. Dense cell suspensions, largely free of the aceticlastic methanogen and supplemented with bromoethanesulfonate, were able to degrade acetone and grow in small volumes in membrane-separated culture devices in which the acetate produced could diffuse into a large volume of medium. Acetone degradation and growth halted when the acetate concentration reached about 10 to 12 mM. Cell suspensions were able to degrade acetone in the absence of active methanogenesis, but the addition of 10 mM acetate inhibited acetone metabolism. Addition of an active culture of Methanosaeta sp. greatly stimulated the rate of acetone degradation. The results show that acetate removal in the mixed culture is not a prerequisite for growth and acetone degradation by the acetone-fermenting bacterium.

Separation and Purification of Organic Acids by Gas Antisolvent Crystallization

Abstract: Citric acid (CA) has successfully been separated from other organic acids, especially oxalic acid which is a byproduct of CA fermentation, by gas antisolvent crystallization wih CO 2 . In this process, crystal grains of CA could be obtained at high speed from an acetone solution by simple pressure regulation. The conditions for the deposition of organic acids are strongly dependent on the saturation ratio of the solute in the solution (C/C sat ) and on the solubilities of the acids in acetone

Purification of bisphenol-A

Abstract: Bisphenol-A produced by the condensation of acetone and phenol is freed of contaminant co-products by melting and crystallization in and from water. The final washing, in hot water, cleanses the crystal surfaces of remaining contaminants without the need for organic solvents.

Determination of organochlorine pesticide residues in river sediments by soxhlet extraction with hexane‐acetone

Abstract: Soxhlet extraction with hexane + acetone (1 + 1 by volume) was used for the extraction of organochlorine pesticide residues from river sediments, followed by Florisil column chromatography clean-up and determination by gas chromatography with an electron-capture detector. Average recoveries exceeding 90 % were obtained using this technique. Organochlorine pesticide residue levels in sediment samples from two major rivers flowing through predominantly rice-growing areas were determined by this method. Relatively high residue levels of organochlorine pesticides such as HCH, heptachlor and endosulfan were found in the sediments.

Synthesis of 2-picoline from acetone over modified ZSM-5 catalysts

Abstract: In the reaction of acetone, formaldehyde and methanol with ammonia over modified ZSM-5 catalysts, 2-picoline and 2,6-lutidine are synthesized selectively. The catalysts studied were H-ZSM-5 with Si/Al ratios, 30, 150 and 280, Pb-ZSM-5, W-ZSM-5 and modified silica-alumina. The yields of 2-picoline obtained were 30–47 wt.-% at 50–60 wt.-% conversions of acetone. The unconverted acetone and methanol can be recycled to increase the over-all yield. Pb-ZSM-5 was identified as the best catalyst.

Vapour-phase reaction of methanol with acetone over alkali containing zeolites

Abstract: Three types of reactions were observed on alkali exchanged A, X and Y zeolites during the vapour phase reaction of methanoi with acetone: the methylation of acetone followed by dehydrogenation to form methyl vinyl ketone ( MVK) ; the Meerwein-Ponndorf-Verley ( MPV ) reaction between acetone and methanol, coupled with the further dehydration to form propene and formaldehyde; and the condensation of acetone followed by further decomposition to form isobutene. The last two kinds of reactions are the main reactions on LiX and NaX, which possess a relatively strong Lewis acidity. When Lewis basicity increases and Lewis acidity decreases, these two reactions are dramatically depressed, which results in an increase in selectivity to MVK. After high energy milling the zeolite becomes amorphous with no change in chemical composition. The catalytic results over these materials also revealed an increase in the production of MVK and the depressing of the other two reactions. This change is attributed to the crush of the zeolite pore structure, which is another factor affecting the product distribution.

The Synthesis of Methyl Isobutyl Ketone over Palladium Supported Zeolites

Abstract: The one-step liquid phase synthesis of methyl isobutyl ketone (MIBK) on supported Pd/ZSM-5 from acetone was extensively studied. Effects of supports, treatment reagents, and reaction variables on the activity and selectivity of MIBK formation were investigated. The catalyst life was also examined. It was found that organic acid pretreatment could enhance MIBK selectivity and catayst life. It is suggested that this enhancement is resulted from an expansion of secondary pores and an increased acidity.

Studies of thermal rearrangements of methyl 3-alkyl-3-methyl-3H-pyrazole-5-carboxylates. Concerted, stepwise, and unclassified mechanisms

Abstract: Studies of the thermal rearrangements of five 3H-pyrazoles are described, in which the migrating groups were methorymethyl, tert-butyl, 1-adamantyl, p-methoxybenzyl, and benzyl. On the basis of reaction products, rearrangement of the (methoxymethyl)pyrazole in benzene, dichloromethane, and methanol at room temperature occurs by a stepwize mechanism, involving discrete ion-pair intermediates. Observed first-order rate constants, for the rearrangement of four of the 3H-pyrazoles in benzene-d 6 and acetone-d 6 at higher temperatures, were determined. The tert-butyl compound also rearranges by a stepwise mechanism in benzene-d 6 , acetone-d 6 , and methanol-d 6 based on the fact that isobutene and tert-butyl methyl ether (in methanol) are coproducts of rearrangement