Showing papers on "Acetone published in 2002"

Deep oxidation of VOC mixtures with platinum supported on Al2O3/Al monoliths

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.

Acetoacetate, acetone, and dibenzylamine (a contaminant in L-(+)-β-hydroxybutyrate) exhibit direct anticonvulsant actions in vivo

Abstract: Summary: Purpose: To investigate whether ketone bodies are directly anticonvulsant. Methods: We tested the effects of acetoacetate (ACA), acetone, and both stereoisomers, d-(−)- and l-(+), of β-hydroxybutyrate (BHB) on sensory-evoked seizures in Frings audiogenic seizure-susceptible mice. Results: We found that these ketone bodies, with the exception of the d-(−)-isomer of BHB, were anticonvulsant in this model. Furthermore, with gas chromatography–mass spectrometry, we confirmed that the activity of l-(+)-BHB was due to dibenzylamine, a chemical contaminant. Conclusions: Our data indicate that the anticonvulsant efficacy of the ketogenic diet may be due in part to the direct actions of ACA and acetone.

Solubility of Phenylacetic Acid, p-Hydroxyphenylacetic Acid, p-Aminophenylacetic Acid, p-Hydroxybenzoic Acid, and Ibuprofen in Pure Solvents

Abstract: The solubility of phenyl acetic acid, p-hydroxyphenylacetic acid, p-aminophenylacetic acid, p-hydroxybenzoic acid, and ibuprofen in water and in a range of organic solvents of relevance to industrial processing is reported. The solvents used are water, methanol, ethanol, 2-propanol, acetone, 4-methyl-2-pentanone, ethyl acetate, chloroform, and toluene. Solubility data are discussed from the standpoint of molecular aspects of solute-solvent interactions and by estimated solid-phase activity.

Complete oxidation of acetone over manganese oxide catalysts supported on alumina- and zirconia-pillared clays

Abstract: The complete oxidation of acetone has been studied over a series of manganese oxide catalysts supported on the unpillared and the Al- and Zr-pillared forms of two natural clays of the smectite class (a montmorillonite and a saponite). The temperatures required for total combustion of acetone over the several catalysts ranged from 610 to 660 K at the relatively low W Mn / F in ratio of 0.40 g Mn min mmol acetone −1 used. A significant influence of the clay supports characteristics on the catalytic performance has been found. According to the general behaviour of the various catalysts throughout the light-off tests, the following order of improving catalytic performance can be established with respect to the pillars composition: Al-pillared clays 2 O 3 , MnO 2 , Al 2 O 3 and ZrO 2 , as well as physical mixtures of ZrO 2 with the unpillared clays. The effect on the catalytic performance of the possible competition between the acetone combustion and aldol condensation processes has also been considered.

Chemical potentials of water and organic solutes in imidazolium ionic liquids: a simulation study

Abstract: The excess chemical potentials of a series of molecules dissolved in the ionic liquid dimethyl imidazolium chloride have been determined by a series of transformations. The molecules are water, methanol, dimethyl ether, acetone and propane. Water and methanol have large negative values of the excess chemical potential (-29kJmol−1 and — 14kJ mol−1 respectively); the polar molecules dimethyl ether and acetone have positive values of about 7kJmol−1 while the value for propane is +26 kJ mol−1. Hydrogen bonding to the anion plays an important part in the stabilization of water and methanol.

Comparison of magnesium sulfate and sodium sulfate for removal of water from pesticide extracts of foods.

Abstract: Water-miscible solvents, such as acetone and acetonitrile, effectively extract both polar and nonpolar pesticide residues from nonfatty foods. The addition of sodium chloride to the resulting acetonitrile-water or acetone-water extract (salting out) results in the separation of the water from the organic solvent. However, the organic solvent layer (pesticide extract) still contains some residual water, which can adversely affect separation procedures that follow, such as solid-phase extraction and/or gas chromatography. Drying agents, such as sodium sulfate or magnesium sulfate, are used to remove the water from the organic extracts. In the present study, we used nuclear magnetic resonance spectroscopy to study the composition of the phases resulting from salting out and to compare the effectiveness of sodium sulfate and magnesium sulfate as drying agents. The study showed that considerable amounts of water remained in the organic phase after phase separation. Sodium sulfate was a relatively ineffective drying agent, removing little or no residual water from the organic solvent. Magnesium sulfate proved to be a much more effective drying agent.

Stabilization of horseradish peroxidase in aqueous-organic media by immobilization onto cellulose using a cellulose-binding-domain

Abstract: A fused protein consisting of a cellulose-binding domain (CBD) and horseradish peroxidase (HRP) was bound to cellulose beads and evaluated in aqueous-organic solvent systems. The CBD–HRP fusion protein containing two different functionalities, a catalytic domain and a binding domain, preserved both capabilities in this non-conventional environment. A six-fold increase in the half-life of the enzyme in buffer resulted from immobilization onto cellulose via CBD. The immobilized enzyme was also more stable than the native enzyme in increasing concentrations of acetone (0–92%). There was a general decrease in activity as the solvent concentration in the mixture increased (in all solvent types: THF, acetone, acetonitrile and ethanol). However, the immobilized enzyme was at all times more active than the soluble enzyme forms. The thermostability of the enzyme in buffer, at 40–60 °C, was also improved by immobilization. The soluble CBD–HRP fusion protein exhibited greater stability (both to organic solvents and temperature), but lower activity, in comparison with the native HRP. This work demonstrates for the first time the use of a cellulose-bound CBD-enzyme as a catalyst in aqueous-organic solvent media.

Determination of acetone, 2-butanone, diethyl ketone and BTX using HSCC-UV-IMS.

Abstract: A combination of a custom-designed ion mobility spectrometer (IMS) with a UV ionization source and a high speed capillary column (HSCC) has been developed as an analytical device for the sensitive detection of volatile organic compounds (VOCs), e.g. 2-propanone (acetone), 2-butanone and 3-pentanone (diethyl ketone) in the gas phase. A fast separation of the three selected substances and benzene, toluene and m-xylene (BTX) – all of which occur in human breath – has been achieved within less than four minutes at a carrier gas flow rate of 4.5 mL min–1. Multi-dimensional correlations presented support the interpretation of the acquired spectra of mixtures. Method detection limits were 2.7 µg L–1 for acetone and 2-butanone and 3.0 µg L–1 for diethyl ketone in nitrogen, respectively. The assay linear dynamic range is 4–320 µg L–1.

Drying process paths of ternary polymer solution coating

Abstract: Drying process paths of a ternary solution consisting of a polymer dissolved in a blend of a solvent and a nonsolvent are analyzed. A 1-D drying model applied to a ternary solution provides composition trajectories followed at different depths in the coating as a function of time, collectively called process paths. The effects of gas-phase mass-transfer coefficient, relative diffusivity and relative volatility, and partial saturation of the gas phase with solvents on these process paths are presented. When the solution coating enters the two-phase region, phase separation may take place, as illustrated by coatings prepared from ternary solutions of cellulose acetate in ketone and methanol. When acetone is the solvent, the coating phase separates. Replacing acetone with methyl ethyl ketone gives homogeneous coatings. Solution phase separation or “blush” is explained in terms of the drying-process paths and their relationship to the two-phase immiscible region.

Decomposition of cumene oxidation product

Abstract: A process for decomposing a cumene oxidation product mixture containing cumene hydroperoxide (CHP) and dimethylphenyl carbinol (DMPC) to produce phenol, acetone and alpha-methyl styrene (AMS) with enhanced safety of operation and reduced by-product formation which comprises the steps: mixing the cumene oxidation product in a stirred or back-mixed reactor with an acid catalyst, with 10 to 100 percent acetone relative to the amount of acetone produced during the decomposition reaction, and with up to 4 weight percent additional amounts of water relative to the reaction mixture, at an average temperature between about 50° C. and about 90° C. for a time sufficient to lower the average CHP concentration of the reactor to between about 0.2 and about 3.0 weight percent, and wherein a portion of DMPC is converted to dicumyl peroxide (DCP); then reacting the reaction mixture from step (a) at a temperature between about 120° C. and 150° C. under plug-flow conditions for a time sufficient to decompose substantially all residual CHP and at least 90 percent of the DCP formed in step (a).

Densities and Viscosities of Acetone, Diisopropyl Ether, Ethanol, and Methyl Ethyl Ketone with a Five-Component Hydrocarbon Mixture from 288.15 K to 308.15 K

Abstract: Densities and viscosities were measured for the systems of four oxygenates (acetone, diisopropyl ether, ethanol, and methyl ethyl ketone) separately with a five-component hydrocarbon mixture at three temperatures (288.15, 298.15, and 308.15) K and atmospheric pressure. The five-component hydrocarbon mixture contains 25 mol % hexane, 10 mol % heptane, 35 mol % 2,2,4-trimethylpentane, 20 mol % toluene, and 10 mol % p-xylene. Densities were determined using a vibrating-tube densimeter. Viscosities were measured with an automatic Ubbelohde capillary viscometer. Excess molar volumes VE and deviations in viscosity Δη for the mixtures were derived from experimental data, and the computed results were fitted to a Redlich−Kister-type equation.

Method for producing bisphenol-A

Abstract: A method for producing bisphenol-A through the continuous feed of phenol and acetone to a reaction unit having at least two reaction regions, wherein an acidic cation exchange resin in which 15 to 50 % of the acid points in the resin is neutralized with a sulfur-containing nitrogen compound is used as a catalyst, and an acetone having a methanol content of 3,000 ppm or less is dividedly fed to the at least two reaction regions The method allows the elongation of the life of an acidic cation exchange resin used as a catalyst

A Study of Some New Acidizing Inhibitors on Corrosion of N-80 Alloy in 15% Boiling Hydrochloric Acid

Abstract: Three new organic inhibitors, namely, dicinnamylidene acetone (DCA), disalicylidene acetone (DSA), and divanillidene acetone (DVA), were synthesized in the laboratory and their inhibiting ...

Ketogenic diet: does acetone stop seizures?

Abstract: BACKGROUND: The mechanism of action of the ketogenic diet, a therapy for refractory epilepsy, is unknown. Our hypothesis is that acetone, one of three ketones elevated by the ketogenic diet, is directly responsible for the diet's anticonvulsant effects. This study examined the basic concepts of this hypothesis. MATERIAL/METHODS: Rats were acutely injected with acetone intraperitoneally at doses of 1 or 10 mmol/kg, or received acetone chronically in drinking water (1% v/v) for 10 days before being injected with a 1 mmol/kg dose of acetone. Controls consumed regular water and were injected with vehicle. A pentylenetetrazole seizure test was administered 15 min after the injections. Following the test, acetone was measured in the cerebrospinal fluid. RESULTS: A 10 mmol/kg injection of acetone suppressed seizures in 60% of rats (P<0.05). A chronic administration of acetone followed by a 1 mmol/kg injection suppressed seizures in 47% of rats (P<0.05). The acetone concentrations in these rats were 10.3I2.3 and 1.0I0.2 mmol/L, respectively. The effect of the acute 1 mmol/kg injection (without acetone pretreatment) was not statistically significant. This dose elevated acetone to 1.1I0.1 mmol/L in the cerebrospinal fluid. CONCLUSIONS: Our findings suggest that acetone is an anticonvulsant and that chronic administration may enhance its action. Linking acetone to the effects of the ketogenic diet requires further research. In particular, it will be important to confirm that the ketogenic diet generates relevant concentrations of acetone.

Adsorption isotherms of acetone on ice between 193 and 213 K

Abstract: [1] The adsorption isotherms of acetone on ice were measured at 193, 203 and 213 K using a volumetric method with mass spectrometric detection. Henry's law applies for values of the acetone partial pressure, Pacetone, lower than 10−3 Pa. Where Henry's law applies, the number of acetone molecules adsorbed per cm2 of ice, is: nads = 90.53 × Pacetone × exp (6610.2/T), with Pacetone in Pa and T in K. The measured enthalpy of adsorption of acetone on ice is ΔHads = −55±7 kJ/mol. Acetone values previously measured in Arctic snow are too high to be due to adsorbed acetone. Acetone was then probably dissolved in ice or in organic aerosols contained in snow. Adsorption of acetone in the snowpack or on ice crystals in cirrus clouds is insufficient to affect Pacetone above the snow or in the clouds.

Preparation of 1-olefins

Abstract: A multi-stage synthesis is effective for preparing 1-olefins from aldehydes. The aldehyde is condensed with acetone to form an α,β-unsaturated ketone. The unsaturated ketone is hydrogenated to yield a saturated alcohol. By dehydrating the saturated alcohol a 1-olefin is obtained. The olefin can be isolated in high yield and purified.

Epoxidation of partially norbornylized linseed oil

Abstract: A new cycloaliphatic epoxide functionalized monomer was prepared from partially norbornylized linseed oil (Dilulin®). Epoxidation was accomplished using three different approaches: peracetic acid, dioxirane, and hydrogen peroxide. Dioxirane was generated from potassium peroxomonosulfate and acetone. Hydrogen peroxide was used with a quaternary ammonium tetrakis(diperoxotungsto) phosphate(3-) as an epoxidation catalyst. The epoxidation reactions were monitored by FT-IR, and the products were characterized using 1 H, 13 C NMR, FT-IR, FT-Raman, and electrospray ionization (ESI) mass spectroscopy. For all three approaches, the effect of reaction time, temperature, catalyst concentration, and pH was investigated. Out of the three approaches, the hydrogen peroxide epoxidation was preferred on the basis of yield and ease of purification. The kinetic data were obtained only for the hydrogen peroxide approach. The reaction was found to be first-order with respect to the alkene double bond and 1.4th-order with respect to the catalyst.

Solubilities of 11 Polar Organic Solvents in Four Polymers Using the Piezoelectric−Quartz Sorption Method

Abstract: The solubilities of methanol, ethanol, propanol, 2-propanol, butanol, 2-butanol, 2-methyl-1-propanol, acetone, methyl ethyl ketone, methyl acetate, and propyl acetate in cis-1,4-polyisoprene, polyisobutylene, poly(n-butyl methacrylate), and poly(vinyl acetate) were measured by the piezoelectric quartz crystal microbalance method at the four temperatures (293.2, 313.2, 333.2, and 353.2) K. In this work, four quartz crystals that were installed in an equilibrium cell enabled multiple solubility measurements. Estimated uncertainties of measured data were ±0.05 K for temperatures, ±0.9% for activities, and ±13.9% for mass fractions in the lowest solubility region, with a lower uncertainty being found in the higher solubility region. The activities obtained were correlated by the UNIQUAC equation with an overall AAD of 5.0%.

Reductive activation of dioxygen for degradation of methyl tert-butyl ether by bifunctional aluminum.

Abstract: Bifunctional aluminum is prepared by sulfating aluminum metal with sulfuric acid. The use of bifunctional aluminum to degrade methyl tert-butyl ether (MTBE) in the presence of dioxygen has been examined using batch systems. Primary degradation products were tert-butyl alcohol, tert-butyl formate, acetone, and methyl acetate. The initial rate of MTBE degradation exhibited pseudo-first-order behavior, and the half-life of reaction was less than 6 h. XPS analysis indicates the formation of sulfate at the surface of bifunctional aluminum. The concentration of surface sulfate varies linearly with increasing strength of the sulfuric acid used during bifunctional aluminum preparation. The rate of MTBE degradation is a function of the concentration of the surface sulfate. MTBE degradation rates increased by a factor of 2 as surface sulfate concentrations increased from 233 to 641 micromol/m2. This relationship implies that sulfate at the surface of bifunctional aluminum acts as a reactive site.