Showing papers on "Acetic acid published in 1997"
TL;DR: In experiments modeling the reactions of the reductive acetyl-coenzyme A pathway at hydrothermal temperatures, it was found that an aqueous slurry of coprecipitated NiS and FeS converted CO and CH3SH into the activated thioester CH3-CO-SCH3, which hydrolyzed to acetic acid.
Abstract: In experiments modeling the reactions of the reductive acetyl–coenzyme A pathway at hydrothermal temperatures, it was found that an aqueous slurry of coprecipitated NiS and FeS converted CO and CH 3 SH into the activated thioester CH 3 -CO-SCH 3 , which hydrolyzed to acetic acid. In the presence of aniline, acetanilide was formed. When NiS-FeS was modified with catalytic amounts of selenium, acetic acid and CH 3 SH were formed from CO and H 2 S alone. The reaction can be considered as the primordial initiation reaction for a chemoautotrophic origin of life.
562 citations
TL;DR: In this paper, the reduction of nitrate to ammonia occurs with nearly complete conversion at room temperature and pressure under aerobic conditions in the presence of iron and either HCl or a pH buffer.
309 citations
TL;DR: The results showed that the concentration of the undissociated form of acetic acid should not exceed 5 gl−1 in the medium for growth to occur, which led to an increased ethanol yield on glucose and the biomass and glycerol yields decreased by 45 and 33%, respectively.
266 citations
Journal Article•
TL;DR: A simple liquid chromatographic method was developed for the estimation of volatile fatty acids in ruminal fluid and the overall recovery was found to be 84.55± 7.10% for acetic acid, 70.65 % tor propionic acid and 88.46±2.98% for butyric acid.
Abstract: A simple liquid chromatographic method was developed for the estimation of volatile fatty acids in ruminal fluid. The procedure involved clarification of the fluid with stannous chloride and estimation of acetic, propionic and butyric acids by HPLC using a reversed-phase column, phosphate buffer pH 2.5 eluent and UV spectrophotometric detector. The overall recovery was found to be 84.55± 7.10% for acetic acid, 70.55±0.65 % tor propionic acid and 88.46±2.98% for butyric acid. A minimum of 1.4 mM acetic acid and 0.56 mM each of propionic and butyric acids could be estimated by the method.
212 citations
Patent•
17 Oct 1997
TL;DR: In this article, a method to produce high purity acetic acid using a multiple distillation process coupled with an optional extraction of acetaldehyde has been described, which results in formation of permanganate reducing compounds such as acetaldehyde, propionic acid and alkyl iodide impurities in intermediate process streams.
Abstract: Disclosed is a method to manufacture high purity acetic acid. Although described in relation to that produced by a low water carbonylation process the present invention is applicable to other mechanisms for production of acetic acid which results in formation of permanganate reducing compounds such as acetaldehyde, propionic acid, and alkyl iodide impurities in intermediate process streams. It has been found that permanganate reducing compounds and alkyl iodides may be conveniently removed from a light phase of an intermediate stream in the reaction process by employing a multiple distillation process coupled with an optional extraction of acetaldehyde. The distillation process involves first distilling a light phase to concentrate the permanganate reducing compounds, and in particular the acetaldehyde, and then separating the permanganate reducing compounds and alkyl iodides in a second distillation tower. The second distillation serves to remove the permanganate reducing compounds and alkyl iodides from methyl iodide, methyl acetate, and methanol mixture. As an optional third step, the twice distilled stream may be directed to an extractor to remove any remaining quantities of methyl iodide from the aqueous acetaldehyde stream to obtain acetic acid as a final product in greater than 99 % purity.
206 citations
TL;DR: In this article, the addition of platinum to the catalyst enhances selectivity and activity of aldehydes, based on the involvement of lattice oxygen (viz, a Mars and Van Krevelen mechanism) and the spillover of activated hydrogen from the platinum to an oxide.
197 citations
TL;DR: Comparative kinetic investigations suggest that tetrazole acts as an acid and as a nucleophilic catalyst in the pyrophosphate bond formation.
Abstract: An improved procedure is described for the efficient and high-yield (76−91%) synthesis of nucleoside diphosphate sugars from the readily available nucleoside 5‘-monophosphomorpholidate and sugar 1-phosphate in the presence of 1H-tetrazole. Comparative kinetic investigations by means of 31P NMR spectroscopy with different additives (1,2,4-triazole, acetic acid, N-hydroxysuccinimide, 4-(dimethylamino)pyridine hydrochloride, perchloric acid) and mass spectrometric analysis suggest that tetrazole acts as an acid and as a nucleophilic catalyst in the pyrophosphate bond formation.
176 citations
TL;DR: The acetate tolerance of E. coli O157:H7 can be explained by fundamental differences in metabolism and intracellular pH regulation, which is able to decrease delta pH and prevent toxic accumulations of intrACEllular acetate anion.
Abstract: Batch cultures of Escherichia coli K-12 grew well in an anaerobic glucose medium at pH 5.9, but even small amounts of acetate (20 mM) inhibited growth and fermentation. E. coli O157:H7 was at least fourfold more resistant to acetate than K-12. Continuous cultures of E. coli K-12 (pH 5.9, dilution rate 0.085 h-1) did not wash out until the sodium acetate concentration in the input medium was 80 mM, whereas E. coli O157:H7 persisted until the sodium acetate concentration was 160 mM. E. coli K-12 cells accumulated as much as 500 mM acetate, but the intracellular acetate concentration of O157:H7 was never greater than 300 mM. Differences in acetate accumulation could be explained by intracellular pH and the transmembrane pH gradient (δpH). E. coli K-12 maintained a more or less constant δpH (intracellular pH 6.8), but E. coli O157:H7 let its δpH decrease from 0.9 to 0.2 units as sodium acetate was added to the medium. Sodium acetate increased the rate of glucose consumption, but there was little evidence to support the idea that acetate was creating a futile cycle of protons. Increases in glucose consumption rate could be explained by increases in D-lactate production and decreases in ATP production. Intracellular acetate was initially lower than the amount predicted by ApH, but intracellular acetate and δpH were in equilibrium when the external acetate concentrations were high. Based on these results, the acetate tolerance of O157:H7 can be explained by fundamental differences in metabolism and intracellular pH regulation. By decreasing the intracellular pH and producing large amounts of D-lactate, O157:H7 is able to decrease δpH and prevent toxic accumulations of intracellular acetate anion.
172 citations
TL;DR: Poly(beta-hydroxybutyrate) accumulation was found to be strongly dependent on the growth rate of the organism before the pulse addition of acetate, and correlated to the difference in maximum acetate uptake rate and the acetate required for growth.
Abstract: The objective of the research was to obtain insights into the behavior of microorganisms under feast/famine conditions as often occur in wastewater treatment processes. The response of microorganisms to such conditions is the accumulation of storage polymers like poly(beta-hydroxybutyrate). The research was performed using a pure culture of Paracoccus pantotrophus LMD 94.21. A steady-state C-limited chemostat culture was switched to batch mode and a pulse of acetate was added. As long as external substrate (acetic acid) was present, the organism grew and accumulated poly(beta-hydroxybutyrate). After depletion of the external substrate, the stored poly(beta-hydroxybutyrate) was used as growth substrate. Poly(beta-hydroxybutyrate) accumulation was found to be strongly dependent on the growth rate of the organism before the pulse addition of acetate. Poly(beta-hydroxybutyrate) accumulation was correlated to the difference in maximum acetate uptake rate and the acetate required for growth. Based on the interpretation of the experimental results, a metabolically structured model has been set up. This model adequately describes the observed kinetics of the poly(beta-hydroxybutyrate) formation and consumption. (c) 1997 John Wiley & Sons, Inc. Biotechnol Bioeng 55: 773-782, 1997.
170 citations
TL;DR: The results indicate that the vacuole also plays a role in homeostasis of the intracellular pH, and the decrease in cytosolic pH caused by external acidification was much more important when the permeant acetic acid was used instead of HCl as the acidulant.
161 citations
TL;DR: In this paper, two different carbon substrates (ethanol and acetic acid) were compared in order to set up the denitrification of a concentrated industrial wastewater (115 mM nitrate, 0 mM nitrite).
TL;DR: In this article, the esterification kinetics of acetic acid with methanol in the presence of hydrogen iodide as a homogeneous acid catalyst was studied with isothermal batch experiments at 30-60°C.
TL;DR: Wound-induced changes in phenolic metabolism causes stem browning (butt discoloration) in harvested lettuce, and PAL was irreversibly inhibited by acetic acid, and this may explain its role as a browning inhibitor.
Abstract: Wound-induced changes in phenolic metabolism causes stem browning (butt discoloration) in harvested lettuce. Stem tissue near the harvesting cut exhibited increased phenylalanine ammonialyase (PAL) activity and accumulation of caffeic acid derivatives. These o-diphenols can be oxidized by the enzyme polyphenol oxidase (PPO) to produce brown pigments. This browning reaction can readily be followed by measuring a* values. Browning was reduced by washing stem disks with solutions of 0.3 M calcium chloride, 1.0 mM 2,4-dichlorophenoxyacetic acid (2,4-D), or 0.5 M acetic acid. These browning inhibitors appear to act in different ways. Calcium chloride decreased PAL activity to 60% of the control, but did not substantially affect the accumulation of phenolic compounds. The mechanism of calcium action could be to decrease PPO activity or to preserve membrane structure. PAL activity was inhibited 60% by 2,4-D, and the biosynthesis of phenolic compounds was strongly inhibited but not suppressed. Acetic acid completely inhibited PAL activity and the production of wound-induced phenolics. PAL was irreversibly inhibited by acetic acid, and this may explain its role as a browning inhibitor.
TL;DR: In this paper, a polycrystalline silicalite membrane was obtained on two kinds of porous supports by hydrothermal synthesis and the pervaporation performance of the membrane obtained was investigated using an acetic acid-water mixture as a feed.
TL;DR: In this article, the authors investigated the sources of carboxylic acid and acetic acid in Denmark and Belgium and found strong correlations with CO and gas NOy which indicate other sources other than traffic emission.
TL;DR: The inhibitory effect of acetic acid in the fermentor was found to be much less than that in a shaker culture, and the mathematical predictions of cell growth in a dialysis reactor were predicted.
Abstract: High-cell-density cultivations of Escherichia coli K12 in a dialysis reactor with controlled levels of dissolved oxygen were carried out with different carbon sources: glucose and glycerol. Extremely high cell concentrations of 190 g/l and 180 g/l dry cell weight were obtained in glucose medium and in glycerol medium respectively. Different behaviour was observed in the formation of acetic acid in these cultivations. In glucose medium, acetic acid was formed during the earlier phase of cultivation. However, in glycerol medium, acetic acid formation started later and was particularly rapid at the end of the cultivation. In order to estimate the influence of acetic acid during these high-cell-density cultivations, the inhibitory effect of acetic acid on cell growth was investigated under different culture conditions. It was found that the inhibition of cell growth by acetic acid in the fermentor was much less than that in a shaker culture. On the basis of the results obtained in these investigations of the inhibitory effect of acetic acid, and the mathematical predictions of cell growth in a dialysis reactor, the influence of acetic acid on high-cell-density cultivation is discussed.
TL;DR: In this article, an alternative synthetic pathway to alumina-based ceramics that does not utilize toxic reagents or volatile organic chemicals (VOCs) was designed, where the aqueous synthesis of water-soluble carboxylate−alumoxane precursors from inexpensive boehmite feed stock.
Abstract: The objective of our research is the development of an environmentally benign process for the fabrication of alumina-based ceramics. We have designed an alternative synthetic pathway to alumina ceramics that does not utilize toxic reagents or volatile organic chemicals (VOCs); the aqueous synthesis of “water-soluble” carboxylate−alumoxane precursors from inexpensive boehmite feed stock. Carboxylate−alumoxanes, [Al(O)x(OH)y(O2CR)z]n, were synthesized by the reaction of boehmite, [Al(O)(OH)]n, with acetic acid (HO2CCH3), methoxyacetic acid (HO2CCH2OCH3), (methoxyethoxy)acetic acid (HO2CCH2OCH2CH2OCH3) and [(methoxyethoxy)ethoxy]acetic acid [HO2CCH2(OCH2CH2)2OCH3]. Carboxylate−alumoxanes are infinitely stable at ambient conditions in solid and solution. In addition, they show no propensity to segregation or polymerization and are readily processed in aqueous or hydrocarbon medium. Upon thermolysis the carboxylate−alumoxanes are converted to alumina. The physical and spectroscopic properties of the carboxylat...
Patent•
05 Aug 1997
TL;DR: In this paper, an integrated process which comprises the steps: (a) contacting in a first reaction zone a gaseous feedstock comprising ethylene and/or ethane and optionally steam with a molecular oxygen-containing gas in the presence of a catalyst active for the oxidation of ethylene to acetic acid and or ethane to acid acid, and (b) contact in a second reaction zone in the absence of additional additional additional acid or acid at least a portion of the first gaseus, including one or more of water, ethane, carbon monoxide,
Abstract: Acetic acid and/or vinyl acetate are produced by an integrated process which comprises the steps: (a) contacting in a first reaction zone a gaseous feedstock comprising ethylene and/or ethane and optionally steam with a molecular oxygen-containing gas in the presence of a catalyst active for the oxidation of ethylene to acetic acid and/or ethane to acetic acid and ethylene to produce a first product stream comprising acetic acid, water and ethylene (either as unreacted ethylene and/or as co-produced ethylene) and optionally also ethane, carbon monoxide, carbon dioxide and/or nitrogen; (b) contacting in a second reaction zone in the presence or absence of additional ethylene and/or acetic acid at least a portion of the first gaseous product stream comprising at least acetic acid and ethylene and optionally also one or more of water, ethane, carbon monoxide, carbon dioxide and/or nitrogen with a molecular oxygen-containing gas in the presence of a catalyst active for the production of vinyl acetate to produce a second product stream comprising vinyl acetate, water, acetic acid and optionally ethylene; (c) separating the product stream from step (b) by distillation into an overhead azeotrope fraction comprising vinyl acetate and water and a base fraction comprising acetic acid; (d) either (i) recovering acetic acid from the base fraction separated in step (c) and optionally recycling the azeotrope fraction separated in step (c) after partial or complete separation of the water therefrom to step (c), or (ii) recovering vinyl acetate from the azeotrope fraction separated in step (c) and optionally recycling the base fraction separated in step (c) to step (b), or (iii) recovering acetic acid from the base fraction separated in step (c) and recovering vinyl acetate from the overhead azeotrope fraction recovered in step (c).
TL;DR: Though the complete taxonomic analysis has not been completed with all the strains, the majority of the acetic acid bacteria isolated have been confirmed to be classified as Acetobacter rancens subsp.
Abstract: Thermotolerant acetic acid bacteria that can grow at 37 to 40°C were collected from places all over Thailand. They were divided into several groups according to their taxonomic and physiological properties, such as rapid ethanol oxidation, rapid acetate oxidation, cellulosic biopolymer formation, growth at 40°C, growth in 3% acetic acid, growth in 8% ethanol, formation of thermotolerant alcohol, and aldehyde dehydrogenases, etc. Though the complete taxonomic analysis has not been completed with all the strains, the majority of the acetic acid bacteria isolated have been confirmed to be classified as Acetobacter rancens subsp. pasteurianus, A. lovaniensis subsp. lovaniensis, A. aceti subsp. liquefaciens, and A. xylinum subsp. xylinum. They produced acetic acid at high temperatures such as 38 to 40°C. Even when acetic acid was initially added to 4%, they still oxidized ethanol to accumulate acetic acid, while 2% of the initial acetic acid was the upper limit for mesophilic strains*1 at higher temperatures. ...
TL;DR: The surface tension of aqueous solutions of formic acid, acetic acid, and propionic acid were measured over the entire concentration range at temperatures (20 to 50) °C as mentioned in this paper.
Abstract: The surface tensions of aqueous solutions of formic acid, acetic acid, and propionic acid were measured over the entire concentration range at temperatures (20 to 50) °C. The experimental values were correlated with temperature and mole fraction. Maximum deviations were in both cases always less than 1%.
TL;DR: Because of its specificity and sensitivity for a large number of carotenoids, this procedure may be of interest for nutritional and epidemiological studies and its speed and robustness make it suitable for analyses on large numbers of subjects.
TL;DR: In this paper, the electrochemical oxidation of ethanol (0.3 M in 0.1 M HClO4) was studied at Pt(111), Pt(557) ≡ Pt(s) − [6(111) × (100)], and Pt(335) ≡ P(s)-[4( 111) x (100)] single crystal electrodes.
Abstract: The electrochemical oxidation of ethanol (0.3 M in 0.1 M HClO4) was studied at Pt(111), Pt(557) ≡ Pt(s) − [6(111) × (100)], and Pt(335) ≡ Pt(s)-[4(111) x (100)] single crystal electrodes. The oxidation pathway leading to acetic acid showed a marked dependence on electrode surface structure; acetic acid formation decreased as the surface step density increased. On the stepped surfaces, facile C−C bond cleavage and high surface poisoning appear to account for the low acetic acid production. Isolation and quantification of acetic acid was achieved with ion chromatography. Oxidation products were generated in a small (∼40 μL) drop of electrolyte solution in contact with a single crystal electrode and analyzed following a short (60 s) electrolysis period. This approach enabled the specific and quantitative determination of soluble reaction products. For Pt(111), results were compared with acetic acid yields determined by in-situ infrared spectroscopy. Agreement between the two methods is within the uncertainty...
TL;DR: The degradation of selected phenoxyalkanoic acid herbicides in soil under laboratory conditions was studied by using enantioselective high-resolution gas chroma tography/mass spectrometry (HRGC/MS) as mentioned in this paper.
Abstract: The degradation of selected phenoxyalkanoic acid herbicides in soil under laboratory conditions was studied by using enantioselective high-resolution gas chroma tography/mass spectrometry (HRGC/MS). The compounds investigated were the chiral 2-(4-chloro-2-methylphenoxy)propionic acid (MCPP) and 2-(2,4-dichlorophenoxy)propionic acid (DCPP) and the achiral (4-chloro-2-methylphenoxy)acetic acid (MCPA), 2,4-(dichlorophenoxy)acetic acid (2,4-D), and dicamba, a benzoic acid derivative. Racemic and enantiopure MCPP and DCPP were incubated in separate experiments. In case of MCPP and DCPP, the herbicidally active R enantiomers were significantly slower degraded than the inactive S enantiomers. Incubation of enantiopure MCPP and DCPP revealed significant enantiomerization with formation of the R enantiomers from the S enantiomers, and vice-versa. Enantiomerization was found to be biologi cally mediated and was not observed in sterilized soil. Degradation followed initially approximate first-order kinetics with ove...
TL;DR: Scandium(III) or lanthanide triflates were found to efficiently catalyse the direct acetylation of primary, secondary and tertiary alcohols with acetic acid.
TL;DR: In this paper, temperature-programmed desorption (TPD) and oxidation (TPO) were used to study decomposition and oxidation of methanol, ethanol, acetaldehyde, formic acid, and acetic acid on aCuO/Al 2 O 3 catalyst.
Abstract: Temperature-programmed desorption (TPD) and oxidation (TPO) were used to study decomposition and oxidation of methanol, ethanol, acetaldehyde, formic acid, and acetic acid on aCuO/Al 2 O 3 catalyst. The volatile organic compounds (VOCs) were adsorbed on the alumina surface and diffused to the CuO to react. Lattice oxygen in CuO is active for deep oxidation, and as lattice oxygen is depleted, diffusion of lattice oxygen to the surface limits the rate of oxidation. Supported CuO dehydrogenates and oxidizes VOCs and the order of reactivity is: HCOOH > CH 3 OH > CH 3 COOH > C 2 H 5 OH > C 2 H 4 O. Nearly all the oxygen in CuO can be extracted by VOCs. In the absence of gas-phase O 2 , extraction of lattice oxygen limits the oxidation rates of acetaldehyde and acetic acid, but gas-phase O 2 rapidly replenishes the lattice oxygen. No less-reactive, partial oxidation products were detected.
TL;DR: In this article, the adsorption of acetic acid on a TiO2(110) surface has been studied using electron stimulated desorption ion angular distribution (ESDIAD) and low energy electron diffraction (LEED).
Abstract: The adsorption of acetic acid on a TiO2(110) surface has been studied using electron stimulated desorption ion angular distribution (ESDIAD) and low energy electron diffraction (LEED). The acetate intermediates arising from the dissociative adsorption of acetic acid form an ordered (2×1) overlayer at saturation coverage. The H+ ESD ion angular distributions can be resolved into two contributions: Those ions desorbing from hydrogen atoms bonded at the oxide substrate, and those ions desorbed via the rupture of the C–H bonds of the acetate. The geometry of the ESDIAD pattern led us to propose that the acetates are bridge bonded with the five-fold coordinated Ti 4+ ions, with their molecular plane perpendicular to the surface. Decomposition of acetate at room temperature occurs under electron beam irradiation, resulting in the desorption of CH2CO and CH3/CH4.
ENEA1
TL;DR: Fractionation analyses showed that in anaerobic conditions the released phosphate comes from cell polyphosphate degradation, which allow us to conclude that Lampropedia spp.
TL;DR: The solubility product (Ksp) of OH-carbonated hydroxyapatite was measured in a 0.1 M acetic acid and sodium acetate buffer solution in a pH range of 4.0-5.8 at a CO2 partial pressure of 10(-3.52) atm and increased with the increase of carbonate content and decreased with the decrease of pH.
Abstract: Information on the solubility of OH-carbonated hydroxyapatite, Ca10(PO4)6(CO3)x(OH)2-2x, previously has not been available. In the present study the solubility product (Ksp) of OH-carbonated hydroxyapatite was measured in a 0.1 M acetic acid and sodium acetate buffer solution in a pH range of 4.0-5.8 at a CO2 partial pressure of 10(-3.52) atm. The equilibrium solubility increased with the increase of carbonate content. The Ksp values decreased with the decrease of pH. For example, Ksps were 10(-119), 10(-123), and 10(-130) for pure hydroxyapatite at pH 4.9, 4.5, and 4.1, respectively. The decrease of Ksp was not accounted for by calcium-carbonate complexation. Ksp measured at isoelectric points (L) was expressed as pL = 118.65 - 0.47316 x (CO2 wt%)2.4176. From this formula, the L values were calculated for pure and fully carbonated hydroxyapatite as 10(-118.7) and 10(102.8), respectively. The L value for pure hydroxyapatite agreed with values measured under carbonate-free conditions. Therefore, the L values were regarded as the Ksp for OH-carbonated hydroxyapatite excluding errors arising from carbonate contamination in the solution.
TL;DR: Strain TA-12T is phenotypically similar to P. freudenreichii, but it produces a large amount of lactic acid and has a distinct fatty acid composition, acid tolerance, and heat resistance, which differentiate it from P.Freuden reichii and other propionic acid-producing bacteria.
Abstract: A non-spore-forming, coryneform bacterium, strain TA-12T, was isolated from spoiled off-flavor orange juice. Growth of this organism occurs at pH 3.2 to 7.5, and optimum growth occurs at pH values between 5.5 and 6.5. This organism produces lactic acid, propionic acid, and acetic acid from glucose. It is catalase negative. The cells are heat resistant and can withstand a temperature of 90°C for 10 min. The DNA G+C content is 66.8 mol%. This strain has an MK-9(H4) respiratory quinone system and contains meso-diaminopimelic acid in its cell wall, and ω-cyclohexyl undecanoic acid is the major cellular fatty acid. The results of a phylogenetic analysis of the 16S rRNA gene of this organism indicated that its highest level of homology is its level of homology with the representative of the classical propionibacteria, Propionibacterium freudenreichii (97.1%). Strain TA-12T is phenotypically similar to P. freudenreichii, but it produces a large amount of lactic acid and has a distinct fatty acid composition, acid tolerance, and heat resistance, which differentiate it from P. freudenreichii and other propionic acid-producing bacteria. On the basis of these findings we propose the name Propionibacterium cyclohexanicum sp. nov. for this organism. The type strain is TA-12 (= IAM 14535 = NRIC 0247).