Showing papers on "Acetone published in 1991"
TL;DR: An integrated solvent (ABE) fermentation and product removal process was investigated and the system proved to be very reliable and high product removal rate even at low solvent concentrations.
Abstract: An integrated solvent (ABE) fermentation and product removal process was investigated. A stable solvent productivity of 3.5 g/L h was achieved by using cells of Clostridium acetobutylicum immobilized onto a packed bed of bonechar, coupled with continuous product removal by pervaporation. Using a concentrated feed solution containing lactose at 130g/L, a lactose value of 97.9% was observed. The integrated fermentation and product removal system, with recycling of the treated fermentor effluent containing only low amount of solvents (/but lactose and acids), leads to only low acid losses. Therefore, most of the acids are converted to solvents, and this results in a high solvent yield of 0.39 g solvents/g lactose utilized. The pervaporation system provided a high product removal rate even at low solvent concentrations. A solvent membrane flux of 7.1 g/m(2) h with a selectivity of 5 was achieved during these investigations. The system proved to be very reliable.
129 citations
TL;DR: In this article, the aldol condensation of acetone was studied over solid base catalysts such as Ca(OH)2, La(OH), ZrO2 and CeO2 in the vapor phase over the temperature range 473-673 K. The reactions were carried out by means of a micropulse reactor, which was directly connected to a GC/MS system.
72 citations
TL;DR: In this paper, surface complexes formed at ambient temperature from acetone, d 6, diethyl ketone, diacetone alcohol, and mesityl oxide on HZSM-5, dehydroxylated HZ SM-5 and NaZSM5 zeolites were studied using FT i.r. spectroscopy.
67 citations
TL;DR: In this article, the products of the reaction of the hydroxyl (OH) radical with methyl tert-butyl ether (MTBE) in NOx-air systems were identified and measured by Fourier transform infrared absorption spectroscopy and gas chromatography.
Abstract: The products of the reaction of the hydroxyl (OH) radical with methyl tert-butyl ether (MTBE) in NOx-air systems were identified and measured by Fourier transform infrared absorption spectroscopy and gas chromatography. The products observed, and their yields, were as follows: t-butyl formate, 76 ± 7%; formaldehyde, 37%; methyl acetate, 17 ± 2%, and acetone, 2.1 ± 0.9%, where the stated error limits represent both random (two standard deviations) and estimated systematic uncertainties. These products account for ca. 95% of the MTBE carbon reacted. Infrared absorption bands which may be due to small amounts of organic nitrate formation were observed, but organic nitrate yields could not be quantified. These data allow a chemical mechanism for the reaction of MTBE with the OH radical in the presence of NOx to be formulated.
62 citations
TL;DR: In this article, the non-degenerate, symmetric stretch (A1,SO3) and (A 1,ClO4) Raman mod were compared by studying the nonsmooth stretch of LiCF3SO3 in polypropylene glycol (PPG 400 and PPG 4000).
Abstract: Solutions of LiCF3SO3 and LiClO4 in acetone and in poly(propylene glycol) (PPG 400 and PPG 4000) have been compared by studying the nondegenerate, symmetric stretch (A1,SO3) and (A1,ClO4) Raman mod
53 citations
TL;DR: In this paper, the reactions of 2-propanol and acetone on the (0001)-Zn and (000-anti 1})-O polar surfaces of zinc oxide were investigated by using temperature-programmed desorption and x-ray photoelectron spectroscopy.
Abstract: The reactions of 2-propanol and acetone on the (0001)-Zn and (000{anti 1})-O polar surfaces of zinc oxide were investigated by using temperature-programmed desorption and x-ray photoelectron spectroscopy. 2-Propanol adsorbed dissociatively on the (0001)-Zn surface to form surface isopropoxide ((CH{sub 3}){sub 2}HCO) species. These alkoxide intermediates underwent both dehydration and hydrogenation reactions to produce propylene and acetone. Acetone dissociated on the (0001)-Zn surface to form enolate intermediates, fingerprinted by a broad envelope in the C(1s) spectrum. These enolates decomposed unselectively above 600 K to deposit carbon, which was oxidized to CO and CO{sub 2} at higher temperatures. Neither acetone nor 2-propanol reacted on the oxygen polar surface, and both were adsorbed molecularly and desorbed intact from this surface below 300 K.
52 citations
TL;DR: The direct oxidation of enolates with dimethyldioxirane (as a solution in acetone) provides the α-hydroxy derivatives in excellent yield as discussed by the authors, which is the main source of α-acetone derivatives.
49 citations
Patent•
09 Apr 1991
TL;DR: In this article, a process including multistage continuous fermen-tation followed by batch fermentation with carefully chosen temperatures for each fermentation step, combined with an asporogenic strain of C. acetobu-tylicum and a high carbohydrate substrate concentration yields extraordinarily high butanol and total solvents concentrations.
Abstract: A process including multistage continuous fermen-tation followed by batch fermentation with carefully chosen temperatures for each fermentation step, combined with an asporogenic strain of C. acetobu-tylicum and a high carbohydrate substrate concentration yields extraordinarily high butanol and total solvents concentrations.
48 citations
TL;DR: Soxhlet and supercritical fluid extracts of freshly cut oriental beech (Fagus orientalis) have been obtained using acetone as mentioned in this paper, and the fatty acids present in the extracts were separated by chemical and Chromatographic methods and analyzed by combined gas chromatography and mass spectrometry.
Abstract: Soxhlet and supercritical fluid extracts of freshly cut oriental beech (Fagus orientalis) have been obtained using acetone. While the yield of the Soxhlet extract was 2.54% the yield of the supercritical acetone extract obtained at 240°C and 6.0–6.5 MPa was 9.55% (dry wood basis). The fatty acids present in the extracts were separated by chemical and Chromatographic methods and analysed by combined gas chromatography and mass spectrometry. Linoleic acid was the major fatty acid in both extracts.
43 citations
TL;DR: In this paper, a novel method for the preparation of α-oso-aldehydes by dimethyl dioxirane oxidation of α -diazoketones is described, particularly useful when the desired compound cannot be purified by chromatography or distillation: the by-products (acetone and nitrogen) can be evaporated and the reaction crude consists only of the pure compound.
42 citations
TL;DR: In this article, the synthesis of epoxides by epoxydation of flavones with isolated dimethyldioxirane (as acetone solution) at subambient temperatures is reported.
Abstract: The synthesis of epoxides 2 by epoxydation of flavones 1 with isolated dimethyldioxirane (as acetone solution) at subambient temperatures is reported. These labile epoxides were isolated and completely characterized by UV, IR, 1 H and 13 C NMR, MS, and C, H analyses.
TL;DR: In this paper, the effects of methyl n-alkyl ketones and n-alkylbenzenes on hepatic cytochrome P450s in vivo and in vitro were investigated.
TL;DR: The experimental data have been correlated and predicted to appreciable accuracy using the Wilson equation as discussed by the authors, which has been correlated with the experimental data for the three constituent binary systems (acetone, chloroform, and benzene) using a dynamic equilibrium still.
Abstract: Vapor-liquid equilibrium data for acetone + chloroform + benzene and for the three constituent binary systems acetone + chloroform, chloroform + benzene, and benzene + acetone have been measured at 101.3 kPa by using a dynamic equilibrium still. The experimental data have been correlated and predicted to appreciable accuracy using the Wilson equation
TL;DR: In this article, a new in situ product separation technique using gas stripping was applied to acetone-butanol-ethanol (ABE) fermentation in a gas-phasecontinuous immobilized cell trickle bed reactor.
Abstract: A new in situ product separation technique using gas stripping was applied to acetone-butanol-ethanol (ABE) fermentation in a gas-phase-continuous immobilized cell trickle bed reactor. Both numerical and experimental studies showed that glucose conversion could be improved when the inhibitory compounds were stripped by fermentation gas. Solvents were stripped preferentially from the fermentation broth, and butanol removal was as efficient as acetone removal in spite of butanol's high boiling point (117°C) because of butanol's high volatility at fermentation concentrations. Since most of the butanol was removed by gas stripping, organic acids played major roles among inhibitory products. Numerical analysis indicated that improvement of glucose conversion by gas stripping was more pronounced at higher gas flow rates, with stronger inhibition kinetics, and under vacuum conditions. Numerical calculation predicted that glucose concentrations higher than 60 g/L could be converted, but this could not be shown experimentally because of increased degeneration.
TL;DR: In this article, the effect of adding ammonia to the surface complexes formed from acetone at mild temperatures on the composition of the products was investigated, and the surface species, both with and without ammonia addition, were also characterized using 13 C cross-polarization magic angle spinning nuclear magnetic resonance.
TL;DR: The complex relationship between the two solvent‐utilizing strains indicates that further work is necessary on the pathways involved in isopropanol and acetone biooxidation and on the effects of operating conditions on the fluxes along such pathways.
Abstract: Much more information concerning the biodegradation kinetics of mixtures of common industrial chemicals, such as organic solvents, needs to be gathered before wastewater biotreatment process performance can become a matter of design. Here, the biooxidation of a solvent mixture comprizing methanol, acetone, isopropanol, and methylene chloride is examined. The fact that the enrichment culture obtained comprized only two solvent-utilizing strains, together with only minor percentages of nonsolvent utilizing satellite strains, was contrary to the theory of microbial competition. In addition, the complex relationship between the two solvent-utilizing strains indicates that further work is necessary on the pathways involved in isopropanol and acetone biooxidation and on the effects of operating conditions on the fluxes along such pathways.
TL;DR: In this paper, the kinetics and equilibria involved in the aldol condensation of acetophenone, acting as carbon acid, and acetone have been studied in aqueous alkaline solution.
Abstract: The kinetics and equilibria involved in the aldol condensation of acetophenone, acting as carbon acid, and acetone have been studied in aqueous alkaline solution. The reactions are all first order ...
TL;DR: The formation of surface complexes during the temperature-programmed desorption, accompanied by conversion, of preadsorbed acetone, diacetone alcohol, mesityl oxide, and diethyl ketone on HZSM-5 was studied using FT i.r. spectroscopy as discussed by the authors.
Patent•
22 Nov 1991
TL;DR: In this article, a process for obtaining a high purity bisphenol from a post-reaction mixture resulting from the step of synthesis of phenol and acetone in the presence of a strong acid cation exhanger catalyst is described.
Abstract: The invention relates to a process for obtaining a high purity bisphenol from a post-reaction mixture resulting from the step of synthesis of phenol and acetone in the presence of a strong acid cation exhanger catalyst, by the way of crystallation and separation by distillation followed by recovery of bisphenol-A from the step of thermal catalytic decomposition of by product of the principal process technology in a multistage process.
TL;DR: In this paper, 4,6-dimethoxy-3-methylindole can be converted by treatment with acetone or acetophenones in methanolic hydrochloric acid into ring-fused indoles in good yields.
TL;DR: The esterification of 2-(4-chlorophenoxy) propionic acid and n-butanol by the lipase from Candida cylindracea in different reaction media showed reverse enantioselectivity.
TL;DR: In this article, nuclear magnetic resonance spectroscopy was used to determine solvent residues in illicit cocaine exhibits, and an internal standard was employed for the quantitative estimation of each of the five most common solvents found in exhibits: benzene, toluene, acetone, methyl ethyl ketone and ethyl ether.
Patent•
25 Sep 1991TL;DR: In this article, a process for producing methacrylic acid from readily available starting materials with a high yield and selectivity, without forming undesirable byproduct or waste materials, such as ammonium sulfate.
Abstract: A process for producing methacrylic acid which comprises: (I) producing acetonecyanohydrin from prussic acid and acetone; (II) hydrating the acetonecyanohydrin obtained in step (I) to form α-hydroxyisobutyric acid amide; (III) reacting the α-hydroxyisobutyric acid amide obtained in step (II) with methyl formate or with methanol and carbon monoxide to form methyl α-hydroxyisobutyrate and formamide; (IV) hydrolyzing the methyl α-hydroxyisobutyrate obtained in step (III) to form α-hydroxyisobutyric acid; (V) dehydrating the α-hydroxyisobutyric acid obtained in step (IV) to form methacrylic acid; and (VI) dehydrating the formamide separated from the products obtained in step (III) to form prussic acid and recycling the prussic acid to step (I) as a starting material. The process is capable of producing methacrylic acid from readily available starting materials with a high yield and selectivity, without forming undesirable by-product or waste materials, such as ammonium sulfate.
TL;DR: Pervaporation through asymmetric polyimide membranes promoted phenol-acetone condensation catalyzed by cation exchange resin as a result of removal of produced water acting as a catalyst inhibitor as discussed by the authors.
Abstract: Pervaporation through asymmetric polyimide membranes promoted phenol–acetone condensation catalyzed by cation exchange resin as a result of removal of produced water acting as a catalyst inhibitor. This resulted in a significant improvement of the reaction process.
TL;DR: In this article, the kinetics of the sorption characteristics of seven different solvents have been measured at 22°, 40°, and 50°C in several cured epoxies.
Abstract: The kinetics of the sorption characteristics of seven different solvents has been measured at 22°, 40°, and 50°C in several cured epoxies. In addition to water, the organic solvents methanol, acetone, isopropanol, ethyl acetate, 1,2-dichloroethane, and toluene were examined. The resin, diglycidyl ether of bisphenol A, was cured with four hardeners, each one resulting in a different epoxy material. The curing agents include triethylenetetramine, nadic methylanhydride, dicyandiamide and m-phenylenediamine, all commonly used substances. Data were analyzed using Fick's diffusion equation. In general, three types of behavior were observed, Fickian diffusion, Case II diffusion, and anomalous diffusion. Fickian or anomalous behavior dominated at all temperatures. Diffusion was both material and solvent dependent. The anomalous nature of isopropanol was noted. Although chemically similar to methanol and about the same size, as acetone, isopropanol is sorbed at a much lower rate. A combination of physical and chemical effects appeared to be responsible for the observations in the epoxies. Diffusion coefficients were estimated for all penetrants and were mostly in the range of 10−9 to 10−11 cm2/s. Where appropriate, apparent activation energies for diffusion were calculated from the kinetic curves.
Patent•
15 May 1991
TL;DR: An aqueous acetone-based nail polish remover comprises: i.e., from 40 to 90% by weight acetone, and ii.e. from 0.001 to 10% of hydrolyzed keratin this paper.
Abstract: An aqueous acetone-based nail polish remover comprises: i. from 40 to 90% by weight acetone, and ii. from 0.001 to 10% by weight of hydrolyzed keratin.
TL;DR: Results indicate that the extraction efficacy of 1-nitropyrene, dinitropyrenes and benzo[a]pyrene is higher with acetone than with dichloromethane, which may be the reason why acetone is the most effective solvent in extraction of mutagens from airborne particulate samples.
TL;DR: Ion clusters were formed in a temperature-variable high-pressure ion source from neat acetone and acetone/water mixtures and subjected to tandem mass spectrometry studies-unimolecular and collisionally activated mass-analyzed ion kinetic energy spectroscopy to suggest ion structures which involve isomerization enroute to dissociation.
Patent•
16 Aug 1991
TL;DR: In this paper, an iron carboxylic acid (CARO) salt was used as a reaction catalyst to obtain high yield in a short time while producing little byproduct by reacting a compound of formula at about 60 deg.C for 5-10hr.
Abstract: PURPOSE:To obtain the subject substance in high yield in a short time while producing little by-product by reacting acetone or an acidic condensate of acetone with 2,2,4,4,6-pentamethyl-2,3,4,5-tetrahydropyrimidine in the presence of an iron carboxylic acid salt as a catalyst. CONSTITUTION:The subject substance can be produced by reacting acetone or an acidic condensate of acetone (e.g. diacetone alcohol) with a compound of formula at about 60 deg.C for 5-10hr in the presence of a carboxylic acid iron salt as the reaction catalyst. The carboxylic acid constituting the catalyst is preferably acetic acid, oxalic acid, lactic acid, citric acid, etc., and the amount of the catalyst is preferably 0.01-0.2mol per 1mol of the compound of formula. The above catalyst may be used in combination with a Lewis acid, protonic acid, etc. The subject substance useful as a photo-stabilizer for polymeric material or synthetic intermediate for pharmaceuticals, etc., can be produced in colorless state by the above process in high yield.