Showing papers on "Acetic acid published in 1977"

Spectrophotometric method for the determination of total steroidal sapogenin

Abstract: A specific method for the spectrophotometric determination of total steroidal sapogenin, based on colour reactions with anisaldehyde, sulphuric acid and ethyl acetate and applicable to microgram amounts, is described.It has been shown that this determination can be carried out directly on a saponin solution and that there is virtually no interference from sugars, sterols, fatty acids and vegetable oil. The sapogenins have the same colorimetric properties whether they are in the free state, bound with sugars, esterified with acetic acid or mono- or polyhydroxylated. The method described is accurate (relative error 1.4%), rapid, easily automated and gives a chromophore with the same absorption spectrum with only one peak at 430 nm for all of the sapogenins tested: diosgenin, tigogenin, hecogenin, smilagenin, yonogenin, tokorogenin, etc. The molar absorption coefficient is approximately 49 000.

Phytotoxicity of acetic acid produced in the anaerobic decomposition of wheat straw.

Abstract: Wheat straw was subjected to aerobic and anaerobic decomposition in suspensions of soil. The products of the aerobic process stimulated the root extension of barley seedlings, whereas the anaerobic fermentation yielded products which inhibited growth. Acetic acid was the phytotoxin present in the greatest amount.

Vapor-liquid equilibriums in the ternary systems water-formic acid-acetic acid and water-acetic acid-propionic acid

Abstract: In previous investigations on ternary systems containing fatty acids we studied experimentally the vapor-liquid equilibria properties of the systems formic acid-acetic acid-propionic acid ( 16) and water-formic acid-propionic acid ( 77). No azeotrope was found at 760 mmHg in the first case, whereas a ternary saddle point azeotrope, boiling at 107.5 OC and containing 42 mole YO water, 54 mole % formic acid, and 4 mole % propionic acid, was revealed in the second system. This information is very useful in regards to the possibility of separating the acids by distillation of their mixture (which is obtained by oxidation of paraffins). As a continuation of the above work, we studied the vaporliquid equilibria behavior of water-formic acid-acetic acid and water-acetic acid-propionic acid. The fatty acids are known to exhibit autoassociation and heteroassociation among the species, and reliable data are available to account for these effects. Hence, the above systems are also suitable to test the thermodynamic model we suggested (76, 77) for computing liquid overall activity coefficients. The values of the latter are important for checking the consistency of the measurements and testing correlations for liquid activity coefficients.

New Method for Synthesis of Various Types of Substituted 2(5H)-Furanones

Abstract: A combination of the reaction of dianions of (phenylthio) acetic acid and its homologs with epoxides, the conjugate addition reaction of 3-phenylthio-2-(5H)-furanones with carbanion species, and the α-alkylation reaction of α-phenylthio-γ-butyrolactones is shown to provide a general method for the synthesis of a variety of substituted α-phenylthio-γ-butyrolactones. Oxidation of these α-phenylthiolactones to the corresponding sulfoxides, followed by pyrolysis furnishes all the types of substituted (3-, 4-, and 5-mono-; 3,4-, 3,5- 4,5-, and 5,5-di-; 3,4,5-tri-) 2(5H)-furanones in good overall yields.

Antimicrobial compositions and methods for utilizing the same employing mixtures of amines

Abstract: There are provided antimicrobial compositions of the low toxicity having enhanced activity against gram positive and gram negative bacteria as well as fungi or protozoa and consists essentially of: (a) an alkyl-N-betaine in amounts up to 40 parts, by weight, (b) an alkyl-N,N-dimethylamine oxide, an alkyl-N,N-dihydroxy-ethylamine oxide, or an acylamido t-amine oxide in amounts up to 40 parts, by weight, and (c) a protonating agent, such as hydrochloric acid, acetic acid or citric acid in an amount sufficient to adjust the pH of the overall composition to from about 4.0 to about 5.5. The composition exhibits skin degerming, cleansing, and deodorizing properties and, particularly, its use exhibits long term inhibition of body odor.

Effect of temperature on growth and activity of a methanogenic culture utilising acetate.

Abstract: Studies with a methanogenic culture enriched for use of acetic acid showed that this culture had an optimum growth temperature of 35 degrees C, with only small differences for other temperatures between 30 and 40 degrees C. The optimum temperature was the same when determined on the basis of biomass production rate during the exponential (log) phase of growth (0.08-0.09 day-1, at 35 degrees C), amount of biomass present at the end of the log phase (100 mg/l), activity of the biomass (rate of conversion in millimoles per day per milligram (dry wt.) biomass present, 0.08 at end of log phase), or biomass yield (mg (dry wt.) biomass produced per millimole acetic acid converted, 1.0-1.1). Temperatures outside the range 30 to 40 degrees C caused marked reductions in the above parameters. The maximum temperature for growth was 42-44 degrees C; the minimum, below 15 degrees C, the lowest temperature studied. Acetic acid conversion to methane was 0.8-1.0 mol/mol, and was independent of temperature.

The Oxidation Activity and Acid-base Properties of V2O5-based Binary Catalysts

Abstract: The oxidation of cis-2-butene, butadiene, and acetic acid was carried out by using a series of V2O5–XnOm (atomic ratio=9 : 1) catalysts with more than twenty metal oxides (XnOm). The results were compared with the dehydration activity for isopropyl alcohol (IPA), as a measure of acidity, and with the ratio, dehydrogenation activity for IPA/dehydration activity for IPA, used as a measure of the basicity of catalyst. The activity for the oxidation of butadiene and that for the isomerization of butene are correlated with the acidity, and the activity for the oxidation of acetic acid with the basicity of the catalyst. The selectivity to maleic anhydride from butene and butadiene is scarcely influenced by the introduction of metal oxides. Butene is mainly oxidized to acetic acid as a result of C–C fission. The selectivity to acetic acid is enhanced when the catalyst is highly acidic, decreasing with increase in basicity. It is concluded that the introduction of metal oxides into V2O5 modifies the acid-base pro...

Method for alleviating psoriasis

Abstract: Pharmaceutical compositions administered to humans and animals topically for treatment of proliferative skin diseases, primarily psoriasis. The composition comprises a pharmaceutical carrier with at least one active ingredient selected from the group consisting of para bromophenacyl bromide, alpha tocopherol, mepacrine, chloroquine, hydroxychloroquine, dibucaine, tetracaine, lidocaine, butacaine, procaine, ethylene diamine tetra acetic acid and ethylene glycol bis(β-amino ethyl ether)-N-N' tetra acetic acid; the compositions may also include one or more unsaturated aliphatic compounds, a glucocorticoid and a prostaglandin.

Chemical and biological studies on the lipopolysaccharide (O-antigen) of Anacystis nidulans.

Abstract: The O-antigen (lipopolysaccharide) of Anacystis nidulans, strain KM, has been isolated from whole cells and from cell wall preparations by phenolwater extraction. The polysaccharide moiety consists of a D-mannose polymer accompanied by smaller amounts of 3- and 4-O-methyl-D-mannoses, D-galactose, D-glucose, L-fucose, D-glucosamine, mannosamine and 2-keto-3-deoxyoctonate. Aldoheptoses are lacking. The degraded polysaccharide is split from lipid A by acid hydrolysis (10% acetic acid, 100°C, 3 h) whereby 2-keto-3-deoxyoctonate is released in small amounts. Degraded polysaccharide forms only one major fraction by Sephadex G-50 gel-filtration. This fraction includes all the sugars mentioned above except L-fucose, which is released during the acetic acid degradation. Periodate studies and methylation analysis revealed that the poly-mannose chain consists of about 75% 1→3 linked and of 25% 1→4 linked D-mannose units. Lipid A of A. nidulans is phosphate-free. The main fatty acid, β-hydroxypalmitic acid, is exclusively amide-bound, presumably to the amino group of D-glucosamine. Other fatty acids, found as minor constituents, are β-hydroxymyristic, palmitic and stearic acids. Lipopolysaccharide of A. nidulans KM exhibits high anticomplementary activity in guineapig serum. It is about 800 times less toxic for adrenalectomized mice than endotoxin from Salmonella typhimurium. The isolated lipopolysaccharide reacts with rabbit antisera against living or heat-killed cells of A. nidulans in passive hemagglutination, when untreated or heated, but not when alkali-treated lipopolysaccharide is used for red blood cell sensibilization. It is concluded that lipopolysaccharide of A. nidulans KM is exposed on the surface of the cell.

Photodegradation of cellulose acetate fibers

Abstract: The photodegradation of cellulose acetate fibers by ultraviolet light in vacuo at 77°K and at ambient temperature was studied. Three kinds of light sources with different wavelengths between 2353 and 6000 A were employed. ESR studies at 77°K show that several kinds of free radicals are produced from cellulose diacetate (CDA) and cellulose triacetate (CTA) fibers when irradiated with light of wavelength shorter than 2800 A. Among these methyl radicals formed decayed within 210 min at 77°K. When the temperature was raised above 77°K, radical transformation occurred at 87°K and most of the free radicals decayed at 193°K, whereas the cellulosic radicals were stable at this and even at higher temperatures. Ultraviolet spectroscopy studies revealed that the main chromophores are the carbonyl function of the acetyl group and acetal groups in the polymer. The photodegradation of the polymers at ambient temperature resulted in the formation of gaseous products (mainly CO, CO2, and CH4), together with the loss of bound acetic acid content and sample weight. Decreases in viscosity and reduction of tensile strength and elongation were also observed in the irradiated samples, revealing that the overt effects of ultraviolet light on cellulose acetate fibers are interpreted in terms of free-radical reactions ultimately leading to main-chain and side-group scissions, unsaturation, and the formation of small molecule fragments. Among these, main-chain scission took place predominantly in CDA fiber and side-group scission in CTA fiber. The mechanism of the fundamental photochemical degradation processes of cellulose acetate fibers is elucidated.

(Acylaryloxy)acetic acid diuretics. 1. (2-Alkyl- and 2,2-dialkyl-1-oxo-5-indanyloxy)acetic acids.

Abstract: The discovery of the (acryloylaryloxy)acetic acids as a new class of potent diuretics prompted the investigation of related bicyclic compounds. Annelated analogues of the parent series, the (2-alkyl- and 2,2-dialkyl-1-oxo-5-indanyloxy)acetic acids, were the subjects of this study. Those compounds, unlike the monocyclic parent compound, lacked the double bond adjacent to the carbonyl group. More importantly, they possessed both saluretic and uricosuric properties. The optimal single 2-substituents for maximal saluretic and uricosuric activity were determined. In general, better activity was observed when a second 2-alkyl substituent (especially methyl) was present in the molecule. Replacement of the carboxy substituent by 5-tetrazolyl generally resulted in a reduction in activity.

Preservation of low acid food products in the absence of chemical preservatives

Abstract: Preservation of low acid food products in the absence of chemical preservatives with the combination of acetic acid and phosphoric acid.

Subcellular structures in fermenting cocoa beans. Effect of aeration and temperature during seed and fragment incubation

Abstract: Chemical reactions in cocoa seeds during fermentation and roasting may depend on post-mortem structural changes in the mesophyll cells. Aeration, temperature and acetic acid concentration vary considerably during commercial fermentation. Light and electron microscopic studies of seeds after artificial fermentations give evidence that the kind and the degree of subcellular structural changes depend on these variations. At 50°C in the presence of acetic acid (35 mM/litre, pH 4.0) water-containing compartments are destroyed shortly before the lipid vacuoles fuse. The hydrophilic particles of the plasm become dispersed within the lipid phase. These changes occur within 6–20 h independent of the presence of air. At 40°C in the absence of acetic acid (citric acid, pH 5.5) the seeds germinate and protein vacuoles in many cells of the mesophyll inflate considerably within 6 h, which is before post-mortem structural changes, different from those following treatment in acetic acid at 50°C, become obvious. Incubation of cotyledon fragments instead of whole seeds submerged in buffer induced these structural changes as well and were even more pronounced. The significance of temperature differences in the range of 40–50°C and induction of germination during fermentation is discussed.

Mechanism of rhodium complex‐catalyzed carbonylation of methanol to acetic acid

Abstract: Many rhodium compounds in conjunction with various forms of iodide have been reported'.' to catalyze the carbonylation of methanol to acetic acid. Although it has been speculated,2 on the basis of reaction rates and product distributions, that various sources of rhodium and iodide may form the same active catalytic species, no direct evidence has been provided as to the specific nature of reactive intermediates, either with any given catalyst precursor or with a variety of catalyst precursors. This work represents an attempt to define the various rhodium species present in the catalytic cycle when one particular compound, namely, a rhodium(II1) halide, is charged to the reaction as the catalyst precursor.* We present a pathway for the reaction that is consistent with the observed' independence of the overall reaction rate on carbon monoxide pressure and methanol concentration.

Purification of spent ethylene glycol

Abstract: Spent ethylene glycol recovered from polyester manufacture contains dissolved antimony catalyst residues and other impurities Prior to distillation of the spent glycol to recover purified ethylene glycol, the antimony compounds are removed by adjusting the pH of the spent glycol to about 2 to 7, preferably 5 to 7, preferably by adding an organic acid (eg, acetic acid) adding an alkali metal borohydride (eg, sodium borohydride) in the absence of oxygen and with intimate mixing to form a metallic antimony precipitate, and recovering the precipitate The process is further improved by adding a catalytic amount of a strong inorganic base, eg, sodium hydroxide, prior to the pH adjustment step, to convert any terephthalyl values to dihydroxyethyl terephthalate which can be recovered