Showing papers on "Acetone published in 1990"

Slowly reversible sorption of aliphatic halocarbons in soils. I. Formation of residual fractions

Abstract: This study describes the formation of slowly reversible sorbed fractions of various halogenated alkanes and alkenes in two surface soils. After the initial sorption equilibration period, the compounds were desorbed by one of two methods. The first used repetitive batch extraction with water. After 16 extractions of 24 to 72 h each, concentrations in the aqueous phase reached low values and a slow desorbing, residual fraction remained in the soil. The residual fraction in the soil was determined independently after extraction with hot acetone, whose efficacy was demonstrated. During desorption, apparent soil-water distribution coefficients increased progressively to as much as 200 times greater than equilibrium sorption coefficients, Kd, obtained separately from sorption isotherms. With increasing sorption equilibration time, the residual became greater in magnitude and less mobile. The second desorption method simulated desorption to infinite dilution over a 96 h period by using Tenax GC polymeric adsorbent beads included in the suspension as a sink for desorbed chemical. Control experiments proved the usefulness of Tenax and showed that desorption from the soil was rate limiting. All compounds studied formed slowly reversible fractions in the soils. This fraction amounted to several percent of the total sorbed from solution. The results indicate that formation of slowly reversible fractions is probably typical of nonpolar organic compounds, including those with weak sorbing tendencies.

Fourier transform infrared spectroscopic studies of the reactivity of vanadia-titania catalysts toward olefins. 1. Propylene

Abstract: The adsorption and transformation of propylene and of several O-containing C{sub 3} organic molecules (namely isopropyl alcohol, acetone, allyl alcohol, acrolein, and acrylic acid) on vanadia-titania in the temperature range 150-673 K have been investigated by IR spectroscopy. At low temperatures (150-200 K), propylene adsorbs as such through {pi}-bonding and reacts later to give an adsorbed species identified tentatively as an allyl radical. Alternatively, it undergoes addition by a surface OH group to given an isopropoxy species. At least two main surface pathways for propylene transformation are active, leading to surface species functionalized at C{sub 2} (isopropoxy species and acetone) and at C{sub 1} (acrolein and acrylates) as well as products arising from coupling of the allyl radical. The results are discussed in relation to literature data concerning the heterogeneously catalyzed selective oxidation of propylene carried out on vanadia-titania as well as on bismuth-molybdate-based catalysts.

Increase in the γ-linolenic acid content by solvent winterization of fungal oil extracted fromMortierella genus

Abstract: The fungal oil extracted fromMortierella ramanniana var.angulispora (IFO 8187) was solvent winterized in order to raise the content of γ-linolenic acid (GLA). Effects of winterization conditions (solvent, oil concentration in the solvent and temperature) and changes of glyceride compositions were discussed. The fungal oil was separated into four diglycerides and 17 triglycerides (TG) with high performance liquid chromatography. The predominant species were POO, POP and LOP, whose contents were 24.4, 22.9 and 9.4% of the total TG, respectively. Ethanol at 4°C gave the highest GLA content of 10.5% in spite of lower yield than with acetone at −20°C. The highest separation efficiency for GLA (ηGLA) was 0.27 with acetone at −20°C and 10% oil concentration, resulting in 8.3% of GLA from the fungal oil at 5.7% LGA. In case of lower oil concentration at 5–20%, ηGLA showed higher in the following order: acetone (−20°C)>n-hexane (−20°C)>acetone (4°C)>petroleum ether (−20°C). The winterization process also proved to be effective for the separation of TG type, Sa2U (Sa; saturated fatty acid; U, unsaturated fatty acid) into the crystallized fraction and SaU2 into the liquid fraction. Acetone at −20°C showed higher separation efficiency for triunsaturated TG than the other solvents.

Anaerobic degradation of acetone by Desulfococcus biacutus spec. nov.

Abstract: From anaerobic digestor sludge of a waste water treatment plant, a gram-negative, strictly anaerobic sulfate-reducing bacterium was isolated with acetone as sole organic substrate. The bacterium was characterized as a new species, Desulfococcus biacutus. The strain grew with acetone with doubling times of 72 h to 120 h; the growth yield was 12.0 (±2.1) g · [mol acetone]-1. Acetone was oxidized completely, and no isopropanol was formed. In labelling studies with 14CO2, cell lipids (including approx. 50% PHB) of acetone-grown cells became labelled 7 times as high as those of 3-hydroxy-buyrate-grown cells. Enzyme studies indicated that acetone was degraded via acetoacetyl-CoA, and that acetone was channeled into the intermediary metabolism after condensation with carbon dioxide to a C4-compound, possibly free acetoacetate. Acetoacetyl-CoA is cleaved by a thiolase reaction to acetyl-CoA which is completely oxidized through the carbon monoxide dehydrogenase pathway. Strain KMRActS was deposited with the Deutsche Sammlung von Mikroorganismen, Braunschweig, under the number DSM 5651.

Basic mixed oxide

Abstract: Basic mixed oxides useful for base catalyzed reactions such as the aldol condensation of acetone and also useful as catalyst supports are made by mixing an acid such as nitric acid or acetic acid with a pseudob oehmite to form a gel, adding magnesium oxide or hydroxide, in a ratio of magnesium to aluminum of about 1:1 to about 10:1, agitating and heating for about 1 to 24 hours, and subsequently drying and calcining. The resulting polymorphic magnesium-aluminum oxide composition is highly effective in the aldol condensation of acetone to isophorone, and other base catalyzed reactions such as isomerization of olefins, aldol condensation of aldehydes.

Method for the preparation of unsaturated ketones

Abstract: β-hydroxyketones are prepared by reacting an aldehyde with acetone in the presence of perhydroisoindole or pyrrolidine and water. The resulting β-hydroxyketone is further reacted in the presence of a solvent mixture to produce α-β-unsaturated ketones.

Preparation of isopropanol

Abstract: Isopropanol is prepared through catalytic hydrogenation of acetone by feeding hydrogen gas and acetone liquid into a reactor having a fixed catalyst bed from its top to form a cocurrent gas/liquid downflow while maintaining the catalyst bed in a trickle bed state. This process can produce isopropanol at a high reaction rate in high yields using a simple reactor.

Method for preparing bisphenol A

Abstract: A method for preparing 2,2-bis(4-hydroxyphenyl)propane comprises reacting acetone and phenol in the presence of an acidic ion-exchange resin as a catalyst wherein the reaction of acetone and phenol is performed while removing a part of the water generated during the reaction from a mixed solution containing acetone and phenol by a pervaporation method. According to the method, the water generated through the reaction can rapidly be removed simultaneously with or alternatively to the reaction by a pervaporation operation and, therefore, the catalytic activity of the ion-exchange resin is not impaired at all. Moreover, any complicated operations associated with the dehydration are not required. Thus, the acidic ion-exchange resin catalyst can continuously be used over a long time period without any treatment for the regeneration thereof. Further, according to the method, bisphenol A can be economically prepared from acetone and phenol in a high conversion rate and high yield.

Enzymes involved in anaerobic degradation of acetone by a denitrifying bacterium

Abstract: The pathway of anaerobic acetone degradation by the denitrifying bacterial strain BunN was studied by enzyme measurements in extracts of anaerobic acetone-grown cells. An ADP- and MgCl2-dependent decarboxylation of acetoacetate was detected which could not be found in cell-free extracts of acetate-grown cells. It is concluded that free acetoacetate is formed by ATP-dependent carboxylation of acetone. Acetoacetate was converted into its coenzyme A ester by succinyl-CoA: acetoacetate CoA transferase, and cleaved by a thiolase into acetyl-CoA. The acetyl residue was completely oxidized in the citric acid cycle. The ADP-dependent decarboxylation of acetoacetate was inhibited by EDTA, but not by avidin. High myokinase activities led to equilibrium amounts of ATP, ADP, and AMP in the reaction mixtures, and prevented determination of the decarboxylase reaction stoichiometry, therefore.

Continuous coenzyme dependent stereoselective synthesis of sulcatol by alcohol dehydrogenase

Abstract: 6-methyl-5-hepten-2-one was reduced to sulcatol ((+)-6-methyl-5-hepten-2-ol) by using alcohol dehydrogenase fromThermoanaerobium brockii in a continuous process. The cofactor NADP(H) was retained by a charged UF-membrane and regenerated by oxidation of isopropanol to acetone. Use of native NADP in a charged UF-membrane reactor proved to be superior to use of PEG coupled NADP in a uncharged UF-membrane reactor.

Adsorption of Co(II) and Cu(II) on silica gel surface modified with pyridinium ion from acetone and ethanol solutions

Abstract: Silica gel modified with pyridinium ion,  Si(CH 2 ) 3 C 5 H 5 Cl − was used to adsorb metal ions from acetone and ethanol solutions. Adsorption of anionic complexes MClnz−n (M = Co(II) and Cu(II)) was much higher from acetone than from ethanol solution. For Co(II) the adsorbed species was the tetrahedral CoCl42− complexes from both solvents while for Cu(II), the adsorbed species was CuCl42− from ethanol solution and the dimeric Cu2Cl62− from acetone solution.

Potassium sulfate water-alcohols systems: composition and density of saturated solutions

Abstract: New data are presented for assessment of the crystallization of potassium sulfate by drowning-out precipitation. The solubility of potassium sulfate in water, in aqueous alcohols, and in aqueous acetone has been determined over the temperature range 15-35 o C, and the densities of the resulting saturated solutions have been measured. In all cases, the presence of either alcohol or acetone significantly reduces both the solubility of potassium sulfate in aqueous solution and the density of its saturated solution

Reaction of anions with activated olefins in the gas phase. a flowing afterglow-selected ion flow tube study

Abstract: Reactions of anions with acrylonitrile, acrolein, methyl vinyl ketone, and methyl acrylate at room temperature under SIFT conditions are described. Stabilized carbanions such as benzyl anion, cyanomethyl anion, cyclohexadienide, acetone enolate, and nitromethyl anion add to activated carbon-carbon double bonds in a process that is competitive with other modes of reaction. With acrylonitrile and methyl acrylate, addition is in a 1,4 or Michael fashion, while with acrolein and methyl vinyl ketone, 1,2 addition completes with 1,4 addition. Hydroxide, methoxide, fluoride, and cyanide do not add to activated olefins by either mode. A mechanism is proposed for hydride transfer from cyclohexadienide to activated olefins

Evaluation of the ability of different concentrations of aqueous acetone, aqueous methanol and aqueous acetone: Methanol (1∶1) to extract aflatoxin from naturally contaminated maize

Abstract: A conventional TLC tank was compared with a specially designed continuous linear development chamber for the ether development phase of the quantitation of aflatoxins by bi-directional High Performance Thin Layer Chromatography (HPTLC). No significant difference was detected in the precision of the method. However, the continuous linear development chamber afforded greater accuracy in aflatoxin determination and required only half the development time and a small fraction of the solvent used in the conventional TLC tank. The ability of different concentrations of aqueous acetone, aqueous methanol and aqueous acetone: methanol (1∶1) to extract aflatoxin from naturally contaminated maize was assessed. With each system, the amount of aflatoxin extracted increased as the ratio of organic solvent: water progressed from 50∶50 to 80∶20 and then decreased or remained constant when the composition of the extraction solvent was altered to 90∶10. 80% aqueous acetone was found to extract 27% more aflatoxin than the corresponding aqueous methanol with the mixed solvent system extracting an intermediate amount of toxin. Clean-up of 80% aqueous acetone extracts of maize by elution through phenol (PH) bonded-phase cartridges resulted in poor aflatoxin retention when the proportion of acetone in 5 ml aliquots of extract was greater than 70%. This could be increased to 100% retention by the addition of an equal quantity of methanol prior to dilution with 1% aqueous acetic acid and elution through the cartridge.

Aldol reaction of nucleoside 5'-carboxaldehydes with acetone. Synthesis of 5'-C-chain extended thymidine derivatives

Abstract: Reaction of 3′-0-(t-butyldimethylsilyl)-2′-deoxythymidine-5′-carboxaldehyde and 2′,3′-dideoxythymidine-5′-carboxaldehyde with acetone afforded a 3:2 mixture of the two (5′R)- and (5′S)-5′-acetonylthymidine derivatives.

Purification of propylene oxide using an aqueous acetone extractive distillation agent

Abstract: Contaminants, including methanol can be removed from an impure propylene oxide feedstock (120) comprising propylene oxide contaminated with from 50 to 1000 ppm of methanol and from 0 to 1 wt.% of acetone, in an extractive distillation process by introducing the impure propylene oxide feedstock (120) into the lower half of a second distillation column (200) having at least 25 theoretical plates, introducing an extractive distillation agent (202) comprising an acetone/water blend containing 20 to 30 wt.% of acetone and, correspondingly, 80 to 70 wt.% of water, at a point 4 to 7 theoretical plates above the crude propylene oxide feed point, at a ratio of feedstock (120) to extractive distillation agent (202) of from 5:1 to 20:1, and withdrawing from the distillation column an overhead distillate fraction (212) comprising propylene oxide contaminated with not more than 60 ppm of methanol, not more than 0.02 wt.% of acetone and not more than 0.3 wt.% of water, and an aqueous bottoms distillate fraction (210) containing substantially all of the methanol, acetone and water introduced into said distillation column (200).

Long-term continuous production of optically active 2-(4-chlorophenoxy)propanoic acid by yeast lipase in an organic solvent system

Abstract: Long-term continuous optical resolution of 2-(4-chlorophenoxy)propanoic acid was carried out by stereoselective esterification with Celite-adsorbed lipase OF 360 from Candida cylindracea using n-tetradecanol as the second substrate in organic solvent systems. The water content of the Celite-adsorbed lipase affected productivity, 1.0 μl water·mg lipase−1 being optimal for preparation of the adsorbed lipase. Water-saturated carbon tetrachloride-isooctane (8:2, v/v) was found to be an excellent organic solvent for the continuous operation. The particle size of Celite had no effect on productivity. Under optimized conditions, the (R)-enantiomer of the acid was continuously esterified with high stereoselectivity in a packed-bed column reactor for 34 days. Furthermore, it was found that treatment of the reactor with acetone made it possible to restore productivity and extend the period of continuous operation for further 29 days.

Updated model of the batch acetone-butanol fermentation

Abstract: The recent models of the Acetone-Butanol fermentation did not adequately describe the culture inhibition by the accumulating metabolites and were unable to simulate the acidogenic culture dynamics at elevated pH levels. The present updated modification of the model features a generalised inhibition term and a pH dependent terms for intracellular conversion of undissociated acids into solvent products. The culture dynamics predictions by the developed model compared well with experimental results from an unconventional acidogenic fermentation ofC. acetobutylicum.

Palladium catalyst reactivation

Abstract: A reactivation process for a deactivated supported palladium catalyst involves contacting the catalyst with an organic polar solvent for naphthalenic compounds at a temperature below about 200° C. The organic polar solvent has a dielectric constant at 25° C. in the range of about 4 to about 80 and has a boiling point at atmospheric pressure in the range of about 30° C. to about 230° C. Preferred organic polar solvents are acetone and methanol, as well as mixtures thereof.

Separation of acetone/water mixture by thin acrylamide gel membrane prepared in pores of thin ceramic membrane.

Abstract: A thin acrylamide gel membrane was prepared in pores of a thin ceramic membrane of silica-alumina by copolymerizing acrylamide of primary monomer and N,N′-methylene-bis(acrylamide) as crosslinking agent. The gel membrane was used for separation of acetone/water mixture by pervaporation to give quite large fluxes of water and an extremely high separation factor of about 2000 at 95 mol% of acetone concentration in the upstream. Such a high separation factor is thought to be due to the fact that the permeation of acetone molecules can be blocked by the network of the acrylamide gel, which shrinks with increasing acetone concentration in the upstream of the membrane.

Process and alkylmercaptoamine catalyst for production of bisphenol-A

Abstract: Bisphenol-A is prepared by reacting an excess of phenol with acetone in the presence of a modified sulfonic acid cationic exchange resin catalyst having a plurality of sulfonic acid sites of the general formula ##STR1## in which IER represents the ionic exchange resin backbone, each a and b is an integer from 0 to about 5, and each R is selected independently from H, OH, SH and alkyl groups. The catalyst exhibits high activity and selectivity at moderate reaction temperatures, low production of colored impurities, and high stability.

Synthesis of 14C‐labelled methylglyoxal and S‐D‐lactoylglutathione

Abstract: [2-14C]Methylglyoxal and S-D-[2-14C]lactoylglutathione were synthesised from [2-14C]acetone. Acetone was oxidised to methylglyoxal by selenium dioxide and was purified by distillation (yield: 23% based on acetone). Methylglyoxal was converted to S-D-lactoylglutathione by reaction with reduced glutathione catalysed by glyoxalase I (EC 4.4.1.5). S-D-Lactoylglutathione was purified by anion exchange chromatography on Dowex 1 (yield: 82%, based on methylglyoxal).

Free radical copolymerization of ethylene and CO with acetone

Abstract: An improvement in the process for the continuous copolymerization of ethylene with carbon monoxide and optionally certain polar comonomers having reactive double bonds, wherein a single phase is maintained in the reactor by means of acetone introduced concurrently with the reactants, whereby reactor fouling is significantly reduced or eliminated.

The response of the Intoxilyzer 4011AS-A to a number of possible interfering substances.

Abstract: Five Intoxilyzer 4011AS-A®s were tested for their response to eleven chemicals and one mixture of chemicals. The air/water partition ratios were also determined for these eleven chemicals and one mixture. The chemicals tested and their approximate partition ratios were the following: acetaldehyde (190:1), acetone (341:1), acetonitrile (578:1), isoprene (1:1), isopropanol (1671:1), methanol (3229:1), methylene chloride (11:1), methyl ethyl ketone (229:1), toluene (5.5:1), 1,1,1-trichloroethane (14:1), trichloroethylene (20:1), and a 50:50 mixture of 1.1,1-trichloroethane and trichloroethylene (14:1). Of the eleven chemicals and one mixture studied during this experiment, only three, isopropanol, toluene, and methyl ethyl ketone, could reasonably interfere with the test, and then only under unusual circumstances—those circumstances being a slight additive effect to a breath ethanol concentration near the level required for prosecution. Any substantial additive effect from these three substances would illuminate the interference light which invalidates the test. The mean illumination point of the interference light was 0.0286 g/210 L for methyl ethyl ketone, 0.0294 for toluene, and between 0.0116 and 0.0292 for the apparent alcohol concentration for isopropanol, depending on the amount of isopropanol metabolized to acetone. Even with these unusual circumstances considered, the Intoxilyzer 4011AS-A must be viewed as an effective way of determining the ethanol concentration in human breath for evidential purposes.