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Showing papers on "Acetic acid published in 1993"


Journal ArticleDOI
TL;DR: One-pot synthesis of the nylon 6-clay hybrid was carried out by the following procedures as discussed by the authors : Montmorillonite was dispersed in water, and then e-caprolactam, acid (phosphoric acid, hydrochloric acid, benzenesulfonic acid, isophthalic acid), trichloroacetic acid, or acetic acid were added to the dispersion.
Abstract: Nylon 6–clay hybrid is a molecular composite of nylon 6 and uniformly dispersed silicate layers of montmorillonite. One-pot synthesis of the hybrid was carried out by the following procedures. Montmorillonite was dispersed in water, and then e-caprolactam, acid (phosphoric acid, hydrochloric acid, benzenesulfonic acid, isophthalic acid, trichloroacetic acid, or acetic acid), and 6-aminocaproic acid were added to the dispersion. The mixtures were reacted at 260°C for 6 h, yielding the nylon 6–clay hybrids (1potNCHs). X-ray diffraction revealed that the silicate layers of 1potNCH by phosphoric acid were uniformly dispersed in the nylon 6 matrix. The 1potNCH had excellent mechanical properties. The strength and the modulus of the hybrid increased compared with previously reported nylon 6–clay hybrid (NCH) synthesized by montmorillonite intercalated with 12-aminolauric acid. The heat distortion temperature (HDT) of the 1potNCH was 160°C, which was 8°C higher than that of NCH. In other 1potNCHs, montmorillonite had a smaller effect on the increase of those properties, and interlayer spacing of montmorillonite was observed at ca. 20 A. © 1993 John Wiley & Sons, Inc.

455 citations


Journal ArticleDOI
TL;DR: The competition between polyphosphate accumulating bacteria (PP bacteria) and another group of microorganisms (tentatively named “G bacteria”) has been observed in laboratory sequencing batch reactors exhibiting enhanced biological phosphate removal (EBPR).

294 citations


Journal ArticleDOI
TL;DR: In this article, the potentials of digested sludge to reduce nitrate and nitrite in the presence of five different carbon sources: glucose, glycerol, acetic acid, lactic acid and methanol were determined.

292 citations


Journal ArticleDOI
TL;DR: In this article, it was shown that deposition of a metal on TiO2 considerably accelerated photocatalytic reduction of carbon dioxide to methane and/or acetic acid, and product distribution was dependent on the kind of metal on the surface of TiO 2.
Abstract: Deposition of a metal on TiO2 considerably accelerated photocatalytic reduction of carbon dioxide to methane and/ or acetic acid, and product distribution was dependent on the kind of metal on the surface of TiO2.

201 citations


Journal ArticleDOI
TL;DR: It is concluded that exogenous administration of L. reuteri R2LC prevents the development of acetic acid-induced colitis in the rat and the morphologic score, MPO activity, and mucosal permeability were almost normalized by Lactobacillus treatment.
Abstract: The potential beneficial effect of exogenous administration of Lactobacillus on acetic acid-induced colitis was evaluated in the rat. Colitis was induced by instillation of 4% acetic acid for 15 sec in an exteriorized colonic segment. This produced uniform colitis with a threefold increase in myeloperoxidase (MPO) activity of the colonic tissue (an index of neutrophil infiltration) and a sixfold increase in plasma exudation into the lumen of the colon (mucosal permeability) as evaluated 4 days after acetic acid administration. Intracolonic administration of L. reuteri R2LC immediately after acetic acid administration, at a dose of 5 ml of 7 x 10(7) colony-forming units (CFU)/ml in two forms: either as pure bacterial suspension or as fermented oatmeal soup, prevented the development of colitis. Thus, the morphologic score, MPO activity, and mucosal permeability were almost normalized by Lactobacillus treatment. Initiating the treatment 24 h after acetic acid administration or using lower doses of 1 ml for 3 consecutive days resulted in a smaller protective effect. We conclude that exogenous administration of L. reuteri R2LC prevents the development of acetic acid-induced colitis in the rat.

185 citations


Journal ArticleDOI
Atsuko Sugimoto1, Eitaro Wada1
TL;DR: Anaerobic incubations of paddy soil collected from Konosu, Japan, were carried out for 10 weeks to clarify the general principles that govern the variation of carbon isotopic composition of bacterial methane from freshwater areas as discussed by the authors.

178 citations


Journal ArticleDOI
TL;DR: In this paper, the catalytic behavior of heteropolyacids remarkably depended on the kind of reaction system, namely, the basicity of reactants, which increases with the decrease in the negative charge of the polyanion.

168 citations


Journal Article
TL;DR: The effects of acetic, lactic and citric acids and pH on the growth and intracellular pH (pHin) of Listeria monocytogenes Scott A and the effect of differing acid and pH environments on pHin was determined.
Abstract: The effects of acetic, lactic and citric acids and pH on the growth and intracellular pH (pHin) of Listeria monocytogenes Scott A were documented and compared for total acid concentrations ranging from 50 mmol ml-1 to 250 mmol ml-1 for acetic and lactic acids and from 25 mmol ml-1 to 100 mmol ml-1 for citric acid. Initial pH values ranged from 4.7 to 6.0. Although the growth rate of L. monocytogenes Scott A was slower when incubated at 25 degrees C than at 37 degrees C, the relative acid and pH inhibition was identical at both temperatures. As the initial pH values decreased and/or the total acid concentrations increased, the growth rates of L. monocytogenes Scott A decreased. Compared at equal initial pH values and on an equimolar total acid basis, the relative inhibition effect was generally acetic > lactic > citric. When based on initial undissociated acid concentrations, the inhibition effect was citric > lactic > acetic. The effect of differing acid and pH environments on pHin was determined. At equimolar total acid concentrations, the pHin of the cell was changed the least by citric acid and the most by acetic acid. Growth rates were influenced by the pHin and the acid used to adjust the system.

162 citations


Journal ArticleDOI
TL;DR: In this article, the authors examined the ratio of propionic to acetic acids as a viable and sensitive indicator for upsets caused by organic overloading in an anaerobic digestion system.

159 citations


Journal ArticleDOI
TL;DR: P pH and lactic acid or acetic acid concentration on Listeria monocytogenes inactivation were studied in brain heart infusion broth using a three strain mixture and 4-D inactivation times were related to the level of undissociated lactic and acetic acids.

156 citations


Journal ArticleDOI
TL;DR: The results indicate that the values of undissociated acid which occur in a silage of pH 4.1-4.5 are about 10-100 times higher than required in order to protect the forage from the growth of enterobacteria and L. monocytogenes.
Abstract: Minimum inhibitory concentrations (MIC) of undissociated lactic, acetic and formic acids were evaluated for 23 strains of enterobacteria and two of Listeria monocytogenes. The evaluation was performed aerobically and anaerobically in a liquid test system at pH intervals of between 4.2 and 5.4. Growth of the enterobacteria was inhibited at 2-11 mmol l-1, 0.5-14 mmol l-1 and 0.1-1.5 mmol l-1 of undissociated lactic, acetic and formic acids, respectively. The MIC value was slightly lower with anaerobic conditions compared with aerobic conditions. The influence of protons on the inhibition was observed for acetic acid at the low pH values. Undissociated lactic acid was 2 to 5 times more efficient in inhibiting L. monocytogenes than enterobacteria. Acetic acid had a similar inhibitory action on L. monocytogenes compared with enterobacteria. Inorganic acid (HCl) inhibited most enterobacteria at pH 4.0; some strains, however, were able to initiate growth to pH 3.8. The results indicate that the values of undissociated acid which occur in a silage of pH 4.1-4.5 are about 10-100 times higher than required in order to protect the forage from the growth of enterobacteria and L. monocytogenes.

Journal ArticleDOI
TL;DR: In this article, the authors used H and C NMR spectroscopy to characterize solvent and ligand effects in precursor solutions used for the deposition of ferroelectric PZT (lead zirconate titanate) thin films.
Abstract: Solvent reactions, ligand substitutions, and the oligomer/polymer backbone structure are important factors in the solution preparation of ceramic films. In this study the authors have used H and C NMR spectroscopy to characterize solvent and ligand effects in precursor solutions used for the deposition of ferroelectric PZT (lead zirconate titanate) thin films. Solutions were prepared by a sequential precursor addition method from carboxylate and alkoxide precursors of the three cations, and the solvent, acetic acid, methanol, and water. The results indicate that acetic acid was a key component in the solution preparation process. As observed previously for single metallic component systems, its presence resulted in esterification reactions, leading in the present case to the formation of methyl, isopropyl, and n-butyl acetates. Second, acetic acid functioned as a chemical modifier, or chelating agent, replacing essentially all of the alkoxy ligands of the original precursors. Since alkoxy replacement appeared to be complete, we may describe the PZT species formed in solution as oxo acetate in nature. Finally, the solvent and ligand behavior of a solution prepared by an inverted mixing order was compared to the behavior of the solution prepared by a sequential precursor addition. The spectra for the two solutions weremore » similar, and only differences in the relative intensities of the ester and alcoholic resonances were observed. 29 refs., 5 figs., 3 tabs.« less

Journal ArticleDOI
TL;DR: Pectins were extracted from apple or sugar-beet cell walls (alcohol-insoluble solids) at pH 4.5 and 20°C in acetate and phosphate buffer solutions, respectively, and in the same buffers containing cyclohexanediaminetetraacetic acid or ethylenediaminet-etric acid.

Journal ArticleDOI
TL;DR: In this article, the influence of inorganic ion content on the thermal decomposition of cellulose was studied by using X-ray scattering, elemental analysis, TGA and FT-IR.

Patent
30 Apr 1993
TL;DR: In this article, a boiling process is proposed in which the boiling liquor contains free soda lye and sodium salts of the alkylbenzole sulphonic acids or aromatic and aliphatic carboxylic acids.
Abstract: For the production of cellulose from wood and annual plants, a boiling process is proposed in which the boiling liquor contains free soda lye and sodium salts of the alkylbenzole sulphonic acids or aromatic and aliphatic carboxylic acids. Delignification is reinforced on the addition of anthraquinone or its derivatives to the boiling liquor. There is no need to restrict the quantities of the anthraquinone additive owing to its price since anthraquinone resists wet oxidation and can be recycled in the boiling process. The solubility and hence the effect of the anthraquinone is enhanced by the use of sulphonic acid salts. In order to recover the processing chemicals contained in the black liquor it is proposed that the dissolved lignin be precipitated with mineral or carboxylic acid, the hemi-celluloses be separated by ultra-filtration and the resins by extraction, where appropriate, and the remaining organic components except for the sulphonic and carboxylic acids salts be burned in the aqueous phase with air and/or oxygen. The chemical solution freed from the wood decomposition products may be returned to the liquor after caustification of the carbonates and, after the partial crystallisation of the aliphatic carboxylic acid salts, made available in the circuit for cellulose production. The sodium acetate isolated by crystallisation can be broken down into acetic acid and sodium hydroxide by diaphragm electrolysis. The soda lye is returned to the boiling process and the acetic acid treated separately.

Journal ArticleDOI
TL;DR: It appears that a buffer system in addition to that provided by acetate is necessary to the maintenance of platelet integrity during storage when plasma carryover is low, and bicarbonate production is suggested.

Journal ArticleDOI
TL;DR: In this paper, a simple and rapid method for the quantitative determination of N -acetyl groups in chitin-chitosan samples consists of an acid hydrolysis conducted at high temperature with a mixture of sulfuric and oxalic acids.

Journal ArticleDOI
TL;DR: In this article, the enantiospecific synthesis of diethylenetriaminepentaacetic acid (DTPA) analogues from L-phenylalanine via a bis N-alkylation strategy is described.
Abstract: The enantiospecific synthesis of diethylenetriaminepentaacetic acid (DTPA) analogues from L-phenylalanine via a bis N-alkylation strategy is described. N-Alkylation of p-nitrophenylalanine benzyl ester (4) occurs readily with dibenzyl and di-tert-butyl [N-(bromoethyl)amino]diacetates 5a and 6b using a phosphate buffer/acetonitrile reaction medium. N,N-Dialkyl (2a, 2b) and N-monoalkyl (3a, 3b) derivatives of L-p-nitrophenylalanine thus are obtained directly in a single operation

Journal ArticleDOI
TL;DR: A palladium acetate mediated oxidative cyclisation has been used as the key step for the syntheses of staurosporine aglycone and related analogues as mentioned in this paper.

Journal ArticleDOI
TL;DR: The results show that urinary ttMA is a promising biological marker for risk assessment of low-concentration benzene exposure and is validated with urine samples collected from normal persons and from refinery workers exposed to benzene concentrations < 1 microL/L.
Abstract: We describe a sensitive and specific high-performance liquid-chromatographic method for determining the benzene metabolite, trans,trans-muconic acid (ttMA) in urine by measuring ultraviolet absorbance at 265 nm. We mix 1 mL of urine sample with 2 mL of Tris buffer containing vanillic acid as internal standard (IS) and percolate this through a preconditioned ion-exchange column. After rinsing the column with phosphoric acid solution, acetate buffer, and deionized water, we elute the analytes with 2 mL of an equivolume solution of 1.5 mol/L sodium chloride and methanol. Of this, 5 microL is injected into the HPLC column. The mobile phase used consists of, per liter, 10 mL of acetic acid, 100 mL of methanol, and the rest 5 mmol/L sodium acetate. The flow rate was started at 1 mL/min and increased to 1.5 mL/min after 6 min. ttMA and IS were detected at 5.2 and 10.2 min, respectively. The lowest detection limit is 125 pg. Analytical recovery and reproducibility generally exceeded 90%. We validated the method with urine samples collected from normal persons and from refinery workers exposed to benzene concentrations < 1 microL/L. The results show that urinary ttMA is a promising biological marker for risk assessment of low-concentration benzene exposure.

Journal ArticleDOI
TL;DR: In this paper, Nafion tubes that function both as a reaction catalyst and a pervaporation membrane have been used to increase the yield in the esterification of acetic acid with methanol and n -butanol by selectively removing products, mainly water, from the reaction mixture.

Journal ArticleDOI
TL;DR: A method of applying organic acids contained in a calcium alginate gel was tested for inhibiting bacteria contaminating sterile lean beef tissue surfaces and both Gramnegative organisms were less inhibited by acetic acid treatments.
Abstract: A method of applying organic acids contained in a calcium alginate gel was tested for inhibiting bacteria contaminating sterile lean beef tissue surfaces. Treated samples were incubated at 5C under controlled moisture conditions for up to 7 days and viable populations of the pathogens determined. For counts of L. monocytogenes, recovered on tryptic soy agar, alginate/lactic acid treatment reduced the log10 counts 1.8 units vs 0.96 for acid treatment without alginate. With acetic acid, log10 reductions were 1.51 vs 2.33 for the alginate/acetic acid vs acetic acid treatment alone. S. typhimurium was reduced 2.11 log10 units vs 1.11 for alginate/lactic acid and acid treatments alone, respectively. The same trend held for E. coli 0157:H7, although the reduction was considerably less, 0.74 log10 reduction vs 0.5 for alginate/lactic acid application vs acid alone. Both Gramnegative organisms were less inhibited by acetic acid treatments.

Patent
08 Oct 1993
TL;DR: In this article, a method to manufacture a palladium-gold catalyst by separately impregnating and fixing the palladium and gold and reducing the fixed solids to free metal on a suitable support is described.
Abstract: A method is provided to manufacture a palladium-gold catalyst by separately impregnating and fixing the palladium and gold and reducing the fixed solids to free metal on a suitable support useful for vinyl acetate manufacture from ethylene and acetic acid.

Patent
30 Jul 1993
TL;DR: In this paper, a food preservative comprising of a specific compound with a germicidal extract extracted from the ball flower of Humulus luplus L., widened in the germicidal spectrum, synergistically enlarged in the Germicidal action, and reduced in the effects to the flavors of foods as much as possible is presented.
Abstract: PURPOSE:To obtain the food preservative comprising the combination of a specific compound with a germicidal extract extracted from the ball flower of Humulus luplus L., widened in the germicidal spectrum, synergistically enlarged in the germicidal action, and reduced in the effects to the flavors of foods as much as possible. CONSTITUTION:The food preservative comprises (A) the extract of the ball flower of Humulus luplus L. with cold water, hot water, an organic solvent such as an alcohol or ether, or the alkaline aqueous solution of an alkali metal hydroxide or sodium carbonate, and (B) a substance selected from among an organic acid (salt) such as sorbic acid (salt), benzoic acid (salt), acetic acid, fumaric acid or adipic acid, glycine, lower fatty acid ester, sugar ester, vitamin B1 ester, polymerized phosphate, ethanol, polylysine, protamine, lysozyme, Glycyrrhiza glabra L.-extracted germicidal substance, Guinea pepper extract, pectin decomposition product, mangosteen pericarp extract, Wasabi japonica extract, chitosan, and phytic acid. The preservative is preferably added to a food in an amount of 0.01-5%.

Journal ArticleDOI
TL;DR: In this paper, the first-order degradation kinetics of bisphenol A diglycidyl ether (BADGE; CAS No. 1675-54-3) have been studied in three water-based food simulants (3% (W/V) acetic acid, distilled water and 15% (V /V) ethanol) at various temperatures.
Abstract: The first-order degradation kinetics of bisphenol A diglycidyl ether (BADGE; CAS No. 1675-54-3) has been studied in three water-based food simulants (3% (W/V) acetic acid, distilled water and 15% (V/V) ethanol) at various temperatures. BADGE and its first and second hydrolysis products were determined by reversed-phase high-performance liquid chromatography with fluorescence detection. Nonlinear regression was used to fit the experimental data at 40, 50 and 60°C with the proposed kinetic equations; Arrhenius' equation was then fitted to the rate constants obtained and the kinetic models were tested by comparing experimental data obtained at 70°C with the kinetic curves calculated using the rate constants predicted for this temperature. The half-life of BADGE was longest in ethanol and shortest in acetic acid. The rings opening in acetic acid appears to happen by means of active hydrogens whereas in the other simulants it is mainly influenced by the formation of acid/base adducts. The results imply that resins which comply with existing legislation on the migration of unreacted monomer may still contaminate foodstuffs.

Journal ArticleDOI
TL;DR: The results of these studies indicate that an increase in the concentration of citrate in a platelet storage medium is associated with significantly increased consumption of glucose and production of lactate and can be reversed by the addition of acetate and reduced to the same levels that were found with saline.

Journal ArticleDOI
TL;DR: In this article, the non-isothermal decomposition of nickel acetate tetrahydrate was studied by means of thermogravimetry (TG), differential thermal analysis (DTA), and differential scanning calorimetry(DSC) from ambient temperature up to 500°C.

Journal ArticleDOI
TL;DR: In this article, the phase behavior of different carboxylic acids/nonionic polymer/water systems has been studied, and experimentally determined phase diagrams can qualitatively be described and compared with a theoretical model, based on Flory-Huggins theory of polymer solubility.
Abstract: The phase behavior of different carboxylic acids/nonionic polymer/water systems has been studied. The carboxylic acids investigated are acetic acid, propionic acid, and butyric acid. The polymers used are a linear random copolymer of ethylene oxide and propylene oxide (UCON) and ethyl(hydroxyethyl)-cellulose (EHEC). These polymers display a lower critical solution temperature (LCST) in water. The decrease of the polarity in the carboxylic acids as the carbon chain increases causes a decrease of the LCST of the system carboxylic acid/polymer/water. As a consequence of this the two-phase region expands. The experimentally determined phase diagrams can qualitatively be described and compared with a theoretical model, based on Flory-Huggins theory of polymer solubility. The cloud-point temperature of the systems decreases as the difference between the effective interaction of polymer-cosolute and cosolute-water increases. (Less)

Patent
04 Aug 1993
TL;DR: In this paper, a method for converting organic materials such as sugars and acids into other organic materials, such as organic acids and salts other than the starting materials with immobilized cells is presented.
Abstract: Apparatus and method for converting organic materials such as sugars and acids into other organic materials such as organic acids and salts other than the starting materials with immobilized cells. The invention is applicable to the conversion of the lactose content of whey, whey permeate or other lactose containing solutions and wastes into lactic acid, propionic acid, acetic acid, and their salts. The fermentation cells may be homolactic, homoacetic and propionic bacteria. The cells are immobilized onto the surface of and within convoluted sheets of a fibrous support material and reactant bearing fluids are caused to flow between the opposing surfaces of such convoluted sheets. Lactose containing solutions such as whey and whey permeate may be co-fermented with homolactic and homoacetic bacteria to acetic acid or acetate. The product may be extracted from its aqueous media by high distribution coefficient solvents particularly trioctylphosphine oxide and long-chain aliphatic secondary, tertiary and quaternary amines. The process and apparatus are particularly amenable to the economical production of calcium magnesium acetate and potassium acetate, which are useful as road deicing and anti-icing agents. The process and apparatus are also amenable to the economical production of calcium propionate and sodium lactate, which are useful as food preservatives.

Journal ArticleDOI
TL;DR: In this article, the reliability of experimental tie-line data was ascertained through an Othmer-Tobias plot and distribution coefficients and separation factors were evaluated over the immiscibility region.
Abstract: Experimental liquid-liquid equilibria of water+acetic acid+dimethyl phthalate and water+acetic acid+diethyl phthalate systems were investigated at 293.16±0.20 K. The reliability of experimental tie-line data was ascertained through an Othmer-Tobias plot. Distribution coefficients and separation factors were evaluated over the immiscibility region. It is concluded that the high-boiling solvents dimethyl phthalate and diethyl phthalate are suitable separating agents for dilute aqueous acetic acid solutions