Showing papers on "Acetic acid published in 1984"
Journal Article•
TL;DR: In this article, two methods were presented for the determinations of the sulfonate and carboxylate groups in sulfite pulps, and good agreement was obtained between the two methods but conductometric titration is preferred for its directness and simplicity.
Abstract: Two methods are presented for the determinations of the sulfonate and carboxylate groups in sulfite pulps. One method involves the initial conversion of the groups to their magnesium salts. A differentiation of the two groups is then made based upon the liberation of magnesium from the carboxylate groups by 0.01 M acetic acid followed by the elution of magnesium from the sulfonate groups by 0.1 M hydrochloric acid. The elution by acetic acid is, however, not completely specific for the carboxylate groups and a small correction must be made. In the second method, the groups are converted to hydrogen form and are then titrated conductometrically with sodium hydroxide in the presence of 0.001 M sodium chloride. Inflexion points mark the end of titration of the strong acids and the total acids. Good agreement was obtained between the two methods but conductometric titration is preferred for its directness and simplicity.
367 citations
TL;DR: Responses of ruminal microbes to long-chain fatty acids in forms of free acids, calcium salts, or triglycerides were measured in trials with rumen cannulated heifers to confirm that these are efficacious for protectingRuminal microbes from adverse effects of fat.
341 citations
TL;DR: It seems unlikely that mutations at one or a few loci would result in C. thermoaceticum cells significantly more acetic acid tolerant than their parental type, as these cells require an internal pH of at least 5.5 to 5.7.
Abstract: When cells of the anaerobic thermophile Clostridium thermoaceticum grow in batch culture and homoferment glucose to acetic acid, the pH of the medium decreases until growth and then acid production cease, at about pH 5. We postulated that the end product of fermentation limits growth by acting as an uncoupling agent. Thus, when the pH of the medium is low, the cytoplasm of the cells becomes acidified below a tolerable pH. We have therefore measured the internal pH of growing cells and compared these values with those of nongrowing cells incubated in the absence of acetic acid. Growing cells maintained an interior about 0.6 pH units more alkaline than the exterior throughout most of batch growth (i.e., ΔpH = 0.6). We also measured the transmembrane electrical potential (ΔΨ), which decreased from 140 mV at pH 7 at the beginning of growth to 80 mV when the medium had reached pH 5. The proton motive force, therefore, was 155 mV at pH 7, decreasing to 120 mV at pH 5. When further fermentation acidified the medium below pH 5, both the ΔpH and the ΔΨ collapsed, indicating that these cells require an internal pH of at least 5.5 to 5.7. Cells harvested from stationary phase and suspended in citrate-phosphate buffer maintained a ΔpH of 1.5 at external pH 5.0. This ΔpH was dissipated by acetic acid (at the concentrations found in the growth medium) and other weak organic acids, as well as by ionophores and inhibitors of glycolysis and of the H+-ATPase. Nongrowing cells had a ΔΨ which ranged from about 116 mV at external pH 7 to about 55 mV at external pH 5 and which also was sensitive to ionophores. Since acetic acid, in its un-ionized form, diffuses passively across the cytoplasmic membrane, it effectively renders the membrane permeable to protons. It therefore seems unlikely that mutations at one or a few loci would result in C. thermoaceticum cells significantly more acetic acid tolerant than their parental type.
255 citations
TL;DR: Data indicate that both ethanol and acetate increase purine nucleotide degradation by enhancing the turnover of the adenineucleotide pool, which supports the hypothesis that acetate metabolism contributes to the increased production of urate associated with ethanol intake.
Abstract: Consumption of alcohol causes hyperuricemia by decreasing urate excretion and increasing its production. Our previous studies indicate that ethanol administration increases uric acid production by increasing ATP degradation to uric acid precursors. To test the hypothesis that ethanol-induced increased urate production results from acetate metabolism and enhanced adenosine triphosphate turnover, we gave intravenous sodium acetate, sodium chloride and ethanol (0.1 mmol/kg per min for 1 h) to five normal subjects. Acetate plasma levels increased from 0.04 +/- 0.01 mM (mean +/- SE) to peak values of 0.35 +/- 0.07 mM and to 0.08 +/- 0.01 mM during acetate and ethanol infusions, respectively. Urinary oxypurines increased to 223 +/- 13% and 316 +/- 44% of the base-line values during acetate and ethanol infusions, respectively. Urinary radioactivity from the adenine nucleotide pool labeled with [8-14C] adenine increased to 171 +/- 27% and to 128 +/- 8% of the base-line values after acetate and ethanol infusions. These data indicate that both ethanol and acetate increase purine nucleotide degradation by enhancing the turnover of the adenine nucleotide pool. They support the hypothesis that acetate metabolism contributes to the increased production of urate associated with ethanol intake.
161 citations
TL;DR: A nonmotile, rod-shaped, nonspore-forming, mesophilic methanogenic bacterium was isolated from sewage sludge and in the presence of CO2 was able to grow and produce significant amounts of methane from acetic acid.
Abstract: A nonmotile, rod-shaped, nonspore-forming, mesophilic methanogenic bacterium was isolated from sewage sludge The cells stained Gram negative In the presence of CO2, the isolate was able to grow and produce significant amounts of methane from acetic acid No growth or methane formation was observed when H2, methanol, pyruvate, propionate, butyrate, formate, or trimethylamine were provided as substrates in the presence of CO2 About 095 mol of CH4 was produced per mole of acetic acid consumed The optimum pH and temperature for growth were 71–75 and 35–40 °C, respectively The mass doubling time was about 24 h under optimum growth conditions The almost complete inhibition of methane formation by 10 μM 2-bromoethanesulfonic acid (2-BES) was reversed in the presence of 50 μM 2-mercaptoethanesulfonic acid (HS-CoM) D-Cycloserine at 01 mg/mL concentration caused complete inhibition of growth Sludge fluid enhanced the rate of methane formation, whereas 05% (w/v) yeast extract was inhibitory The optimum
153 citations
TL;DR: In this paper, a two-stage, one-flask operation using NaBH4/2-propanol, then acetic acid was used to convert phthalimides to primary amines.
144 citations
Patent•
16 Mar 1984
TL;DR: In this paper, a buffered gelling/foaming agent and resulting gelled aqueous inorganic acid solution involving a N,N-bis (2-hydroxyethyl) fatty amine acetic acid salt (e.g., tallow ammonium acetate); alkali metal acetate; and acetic acids buffered system is presented.
Abstract: A novel buffered gelling/foaming agent and resulting gelled aqueous inorganic acid solution involving a N,N-bis (2-hydroxyethyl) fatty amine acetic acid salt (e.g., N,N-bis (2-hydroxyethyl) tallow ammonium acetate); alkali metal acetate; and acetic acid buffered system. The buffered gelling/foaming agent compositions exhibit pragmatic advantages in preparation, handling and use particularly at low temperatures because of low pour points (e.g., 5°-10° F.). Furthermore, the buffered gelling agent more efficiently utilizes the active ingredients in terms of desired viscosity rise as a function of concentration. The resulting gelled aqueous inorganic acid solutions using the buffered gelling agent exhibit a novel viscosity rise and calcium ion viscosity contribution as the concentrated acid is partially spent (i.e., approaches 12%), yet the totally spent acid returns to a nominal viscosity and is a foaming medium. As such, the novel buffered gelling agent and resulting gelled acid solutions are useful in acidizing and fracturing subterranean formations.
139 citations
Patent•
15 Jun 1984
TL;DR: In this article, an integrated process for the preparation of ethanol from methanol, carbon monoxide and hydrogen feedstock is disclosed, the process featuring the steps of esterifying methanols and acetic acid to form methyl acetate; carbonylating the methylacetate to form acetic anhydride; esterification acetic aldehydes with a lower aliphatic alcohol in an anhydrous zone to form the corresponding alphatic acetate.
Abstract: An integrated process for the preparation of ethanol from methanol, carbon monoxide and hydrogen feedstock is disclosed; the process featuring the steps of esterifying methanol and acetic acid to form methyl acetate; carbonylating the methyl acetate to form acetic anhydride; esterifying acetic anhydride with a lower aliphatic alcohol in an anhydrous zone to form the corresponding aliphatic acetate; hydrogenating the aliphatic acetate in a second anhydrous zone to form ethanol and the corresponding aliphatic alcohol; and separating the formed ethanol stream into an ethanol product stream and/or aliphatic alcohol recycle stream, which is recycled to react with acetic anhydride.
136 citations
TL;DR: It is found that para-substituted phenyl-terpyridine ligands can easily be isolated as hydrobromides from acetic acid and purification turned out to be easy.
Abstract: Up to now the synthesis of para-substituted phenyl-terpyridine ligands was difficult with respect to the purification of the reaction products. We have found that these compounds can easily be isolated as hydrobromides from acetic acid. Starting from the hydrobromides the purification turned out to be easy. Synthesis of para-substituted Cl-, Br-, H3C-, H2BrC-, HO- 2,6-Bis(2-pyridyl)-4-phenylphyridine is reported.
133 citations
TL;DR: The combined results have shown that the undissociated acetic acid was much more inhibitory than the ionized acetate ion, which means that at low pH (below 6.0), undissociable acetic Acid is responsible for growth inhibition, and at high pH (above 6. 0), ionized Acetic acid is responsiblefor growth inhibition.
Abstract: The production of acetic acid by Clostridium thermoaceticum was studied by using batch fermentations. In a pH-controlled fermentation with sodium hydroxide (pH 6.9), this organism was able to produce 56 g of acetic acid per liter. On the other hand, when the pH was not controlled and was decreased during fermentation to 5.4, the maximum attainable acetic acid concentration was only 15.3 g/liter. To obtain a better understanding of the end product inhibition, various salts were tested to determine their effect on the growth rate of C. thermoaceticum. An inverse linear relationship between the growth rate and the final cell concentration to the sodium acetate concentration was found. By using different concentrations of externally added sodium salts, the relative growth inhibition caused by the anion was found to be in the order of acetate > chloride > sulfate. Various externally added cations of acetate were also examined with respect to their inhibitory effects on growth. The relative magnitude of inhibition on the growth rate was found to be ammonium > potassium > sodium. The combined results have shown that the undissociated acetic acid was much more inhibitory than the ionized acetate ion. Complete growth inhibition resulted when the undissociated acetic acid concentration was between 0.04 and 0.05 M and when the ionized acetate concentration was 0.8 M. Therefore, at low pH (below 6.0), undissociated acetic acid is responsible for growth inhibition, and at high pH (above 6.0), ionized acetate ion is responsible for growth inhibition.
120 citations
TL;DR: The fermentation of d-xylose, the major sugar-cane bagasse hemicellulose component, to ethanol by Pachysolen tannophilus is inhibited by various factors produced or released during acid hydrolysis of the bagasse or during the fermentation process as discussed by the authors.
Patent•
13 Sep 1984
TL;DR: In this article, dilute aqueous acetic acid streams are treated by a sequence of steps whereby the acid values are converted to ethanol which may be recovered in substantially anhydrous form.
Abstract: Dilute aqueous acetic acid streams are treated by a sequence of steps whereby the acetic acid values are converted to ethanol which may be recovered in substantially anhydrous form The acetic acid is extracted from water with an extractive solvent and esterified by reaction with an alcohol such as amyl alcohol The ester is reacted with hydrogen in a hydrogenolysis reaction to form ethanol and the esterification alcohol, and ethanol product is recovered
TL;DR: Olefins are converted into allylic acetates by treatment in acetic acid with a catalytic amount of palladium bis(trifluoroacetate) and one equivalent of benzoquinone as oxidant as mentioned in this paper.
TL;DR: In this article, it is shown that more than 60% of the cell carbon is derived from CO2 and the rest from formate and that CO2 fixation does not proceed via the Calvin cycle, and the capacity to synthesize an acetate unit from two C1-compounds obviously distinguishes D. baarsii from those Desulfovibrio species which require acetate as a carbon source in addition to CO2.
Abstract: Desulfovibrio baarsii is a sulfate reducing bacterium, which can grown on formate plus sulfate as sole energy source and formate and CO2 as sole carbon sources. It is shown by 14C labelling studies that more than 60% of the cell carbon is derived from CO2 and the rest from formate. The cells thus grow autotrophically. Labelling studies with [14C]acetate, 14CO and [14C]formate indicate that CO2 fixation does not proceed via the Calvin cycle. The labelling patterns of alanine, aspartate, glutamate, and glucosamine indicate that acetate (or activated acetic acid) is an early intermediate in formate and CO2 assimilation; the methyl group of acetate is derived from formate, and the carboxyl group from CO2 via CO; pyruvate is formed from acetyl-CoA by reductive carboxylation. The capacity to synthesize an acetate unit from two C1-compounds obviously distinguishes D. baarsii from those Desulfovibrio species, which require acetate as a carbon source in addition to CO2.
TL;DR: Substrate interactions are important in the kinetics of secondary substrate utilization and Pseudomonas sp.
Abstract: Secondary substrate utilization of methylene chloride was analyzed by using Pseudomonas sp. strain LP. Both batch and continuously fed reactors demonstrated that this strain was capable of simultaneously consuming two substrates at different concentrations: the primary substrate at the higher concentration (milligrams per liter) and the secondary substrate at the lower concentration (micrograms per liter). The rate of methylene chloride utilization at trace concentrations was greater in the presence of the primary substrate, acetate, than without it. However, when the substrate roles were changed, the acetate secondary substrate utilization rate was less when methylene chloride was present. Thus, substrate interactions are important in the kinetics of secondary substrate utilization. Pseudomonas sp. strain LP showed a preference toward degrading methylene chloride over acetate, whether it was the primary or secondary substrate, providing it was below an inhibitory concentration of ca. 10 mg/liter.
TL;DR: The hypothesis that the Custers effect in this yeast is due to a disturbance of the redox balance, resulting from the tendency of the organism to produce acetic acid, and its inability to restore the balance by production of glycerol is supported.
Abstract: Aerobic growth of the yeast Brettanomyces intermedius CBS 1943 in batch culture on a medium containing glucose and yeast extract proceeded via a characteristic pattern. In the first phase of growth glucose was fermented to nearly equal amounts of ethanol and acetic acid. After glucose depletion, growth continued while the ethanol produced in the first phase was almost quantitatively converted to acetic acid. Finally, after a long lag phase, growth resumed with concomitant consumption of acetic acid. When the culture was made anaerobic during the first phase, growth, glucose consumption and metabolite production stopped immediately. This Custers effect (inhibition of alcoholic fermentation as a result of anaerobic conditions) was transient. After 7-8 h the culture was adapted to anaerobiosis, and growth and ethanol production resumed. The lag phase could be shortened at will by the introduction of hydrogen acceptors, such as oxygen or acetoin, into the culture. Glycerol production was not observed during any phase of growth. These results support the hypothesis that the Custers effect in this yeast is due to a disturbance of the redox balance, resulting from the tendency of the organism to produce acetic acid, and its inability to restore the balance by production of glycerol.
TL;DR: Under aerobic growth conditions Lactobacillus plantarum produced acetic acid in addition to lactic acid, and it was found that lactic acids was predominantly produced at first, and then when the carbohydrate was nearly exhausted, lactic Acid was metabolized further to acetic Acid.
Abstract: Under aerobic growth conditions Lactobacillus plantarum produced acetic acid in addition to lactic acid. It was found that lactic acid was predominantly produced at first, and then when the carbohydrate was nearly exhausted, lactic acid was metabolized further to acetic acid. The most likely enzyme involved in the aerobic metabolism of L. plantarum is pyruvate oxidase. Its activity is enhanced in the presence of oxygen and is reduced in the presence of glucose. The specific activity of pyruvate oxidase is highest at the beginning of the stationary-growth phase, where a strong increase in acetic acid production was also observed.
TL;DR: In this paper, the niobic acid catalysts were more effective than cation exchange resin, SiO2-Al2O3, HZSM-5, and solid super acids such as ZrO2 −SO42−, TiO2−SO42 −, and Fe2O 3−S42−.
Abstract: The niobic acids calcined at moderate temperatures of 120–300 °C showed high catalytic activities (52–75% conv. in 1 h) and selectivities (100%) for the esterification at reaction temperatures of 120–160 °C. No catalyst deactivation was observed even after the use for 60 h. The niobic acid catalysts were more effective than cation exchange resin, SiO2–Al2O3, HZSM-5, and solid super acids such as ZrO2–SO42−, TiO2–SO42−, and Fe2O3–SO42−.
TL;DR: These experiments indicate that a corrinoid is involved in acetate synthesis and probably not in methanogenesis from CO2; the metal is light-reversibly alkylated and functions in methyl transfer to the acetate methyl.
Abstract: Autotrophic CO2 fixation byMethanobacterium thermoautotrophicum proceeds via a total synthesis of activated acetic acid. The origins of the individual carbon atoms were studied in vitro and in vivo. The experiments described showed:
(1)
Two different routes of CO2 reduction lead to the individual carbon positions in acetate.
(2)
The carboxyl carbon is provided by a cyanide-sensitive enzyme which reduces CO2 to a bound intermediate with the oxidation state of CO. This intermediate can be supplied by gaseous CO rather than by formate, when its synthesis from CO2 is blocked by cyanide. The characteristics of the enzymic reaction are those of carbon monoxide dehydrogenase.
(3)
The methyl carbon is derived from CO2 via a different cyanide-insensitive CO2 reduction path, which probably shares the initial intermediates of methanogenesis from CO2 and H2. It does not involve methyl coenzyme M. It is concluded that the pathway of autotrophic CO2 assimilation into activated acetic acid inMethanobacterium is mechanistically related to the clostridial total acetate synthesis.
TL;DR: The diffusion of sodium chloride and acetic acid into herring muscle and their subsequent effects on the myotibrillar proteins were studied at different temperatures and fish:cure ratios as mentioned in this paper.
Abstract: The diffusion of sodium chloride and acetic acid into herring muscle and their subsequent effects on the myotibrillar proteins were studied at different temperatures and fish:cure ratios. Acid was found to penetrate tissue more quickly than salt. The acid and salt cause an initial “hardening” of the tissue, the extent of which is proportional to the concentration of each, but it is considered that the resultant fall in pH activates muscle cathepsins. SDS PAGE indicated that proteolysis of the myosin heavy chains was concomitant with subsequent tissue softening. Electron microscopy detected little disintegration of myofilaments, but extensive break-up of Z-lines.
TL;DR: Vapor phase carbonylation of methanol was catalyzed by strong solid acids in the absence of halogen promoter under pressurized conditions in this paper, where methyl acetate, methyl formate and acetic acid were obtained as carbonylated product with dimethyl ether as main by product.
Abstract: Vapor phase carbonylation of methanol was catalyzed by strong solid acids in the absence of halogen promoter under pressurized conditions. Methyl acetate, methyl formate and acetic acid were obtained as carbonylated product with dimethyl ether as main by product. Hydrocarbons were also formed at high temperature.
TL;DR: Of the 13 species of lactic acid bacteria tested, Streptococcus lactis subsp.
Abstract: A simple gas-liquid chromatographic procedure for analyzing ethanol, acetic acid, acetoin, and racemic and meso-2,3-butylene glycol in broth media is described. Overnight broth cultures were filtered or centrifuged, and the filtrate or supernatant was treated with formic acid to aid separation of volatile fatty acids. Samples were then directly analyzed by gas-liquid chromatography on a 20% Tween 80-Chromosorb W-AW column and propionic acid as an internal standard. A complete analysis took ca. 8 min. The method can be used to distinguish homofermentative from heterofermentative lactic acid bacteria based on the level of ethanol produced and citrate-utilizing from non-citrate-utilizing lactic acid bacteria based on the levels of acetic acid produced. The method also has potential in distinguishing other bacterial fermentations. Of the 13 species of lactic acid bacteria tested, Streptococcus lactis subsp. diacetylactis was the major producer of 2,3-butylene glycol (total range, 0.3 to 3.5 mM), and, except for strain DRC1, both the racemic and meso isomers were produced in approximately equal amounts.
Patent•
14 Feb 1984
TL;DR: A liquid bactericide for foods and food processing machines or utensils, said bactericide comprising as active ingredients 98.0 to 96.7% (W/V) of an organic acid selected from the group consisting of lactic acid, acetic acid, citric acid, tartaric acid, gluconic acid and ascorbic acid.
Abstract: A liquid bactericide for foods and food processing machines or utensils, said bactericide comprising as active ingredients 98.0 to 2.3% (W/V) of ethyl alcohol, 1.0 to 96.7% (W/V) of an organic acid selected from the group consisting of lactic acid, acetic acid, citric acid, tartaric acid, gluconic acid, malic acid, ascorbic acid and phytic acid and 1.0 to 96.7% (W/V) of phosphoric acid; said bactericide being capable of sterilizing within 30 seconds when used in an aqueous solution, such that the concentration of active ingredients in solution consists of 14 to 1% (W/V) of ethyl alcohol, 13.0 to 0.3% (W/V) of said organic acid and 0.7 to 0.03% (W/V) of phosphoric acid.
TL;DR: In this paper, the authors used a reverse phase high pressure liquid chromatography to extract L -[18F]6-fluorodopa with which the dopamine rich regions of the brain can be demonstrated and with which dopamine metabolism can be measured by positron emission tomography.
TL;DR: In this paper, a paper, thin layer (TLC) and gas liquid chromatography (GLC) analysis of cottonseed extracts was performed to identify the major flavonoid species in cottonseed.
Abstract: Methanolic extracts of cottonseeds were found to possess antioxidant activity. Separation of antioxidant components was achieved by paper, thin layer (TLC) and gas liquid chromatography (GLC) and spectral analysis. Chromatographic technique indicated that the flavonoids quercetin and rutin were the major flavonoids present. GLC analysis of the cottonseed extract eluted from TLC plates, developed in n-butanol/acetic acid/water (4:1:5, v/v/v) and ethyl acetate/methyl ethyl ketone/formic acid/water (5:3:1:1, v/v/v) solvents, corresponded in retention times to the rutin standard (10−4 M). TMS derivatives of the aglycone fraction, prepared by acid hydrolysis, correlated to the retention time of quercetin. Spectral analysis of the aglycone fraction also indicated quercetin derivatives to be present in cottonseed. The glycosyl substitution of the flavonoids were identified by the 3 chromatographic procedures to be glucose and rhamnose. Chromogenic spray reagents were used to further characterize the cottonseed flavonoids and flavonoid components on TLC and paper chromatography. The investigation, therefore, demonstrated that quercetin derivatives appear to be the main flavonoid species in cottonseed. Rutin was found to be one of the major quercetin glycosides. Quercetin and rutin are shown to possess potent antioxidant activity.
TL;DR: It is presumed that acetic, propionic, and oleic acids are factors influencing the predominant residence of some species of Propionibacterium and coagulase-negative Staphylococcus on normal human skin.
Abstract: The minimum inhibitory concentration (MIC) of acetic and propionic acid for resident bacteria on normal human skin, such as Propionibacterium acnes and Staphylococcus epidermidis, was 25 mg/mL or more at any pH tested (pH 5.5-6.8). While the MIC of these acids for most of the transient bacteria was markedly decreased by lowering the pH of the media and at pH 5.5, the mean pH value of the normal human skin, the MIC was 6.25 mg/mL or less. The MIC of oleic acid for some strains of Gram-positive transient bacteria of Streptococcus, Micrococcus, or Bacillus was 100 micrograms/mL or less at all pH's tested. Staphylococcus aureus was resistant to this acid at pH 6.8, but became as sensitive as Streptococcus when the pH was lowered. The growth of P. acnes, the most predominant resident bacterium, was enhanced markedly and reached a maximum level at 6.25 mg/mL of propionic acid, 12.5 mg/mL of acetic acid, and 50-100 micrograms/mL of oleic acid. On the basis of these results, we presumed that acetic, propionic, and oleic acids are factors influencing the predominant residence of some species of Propionibacterium and coagulase-negative Staphylococcus on normal human skin.
TL;DR: The results show that more than one extraction procedure is needed to study all the cholecystokinin components in brain tissue and demonstrates the necessity of using at least two chromatographic systems for such studies.
Abstract: Samples of rat striatum and synthetic sulphated cholecystokinin octapeptide were extracted by different procedures and the solubilised cholecystokinin-like immunoreactivity analysed by gel filtration and ion-exchange chromatography. Ice-cold 90% methanol extraction gave the greatest recovery of tissue immunoreactivity without any major modification of the extracted components. The 33-amino acid form of cholecystokinin was poorly recovered by this extractant . Boiling water or a combined boiling water/acetic acid extraction gave efficient recovery of tissue immunoreactivity but chemically modified a substantial part of the octapeptide-like component. Boiling in acetic acid alone also produced this modification but in addition resulted in poor recovery of the octapeptide-like component. The combined water/acetic acid extraction gave reasonable to good recovery of all added cholecystokinins and gastrins, including the 33-amino acid form of cholecystokinin. Ice-cold 0.1 M HCl was less efficient than 90% methanol at solubilising tissue immunoreactivity and resulted in a substantial modification of the octapeptide component distinct from that produced by boiling extractions, possibly desulphation . The results show that more than one extraction procedure is needed to study all the cholecystokinin components in brain tissue and demonstrates the necessity of using at least two chromatographic systems for such studies.
TL;DR: Les disulfures 2,4 de diarylthio-2,4 dithiadiphosphetannes 1, 3, 2, 4, permettent de realiser l'echange O/S dans des acides et amides carboxyliques.
Abstract: Les disulfures-2,4 de diarylthio-2,4 dithiadiphosphetannes-1,3,2,4, permettent de realiser l'echange O/S dans des acides et amides carboxyliques. Obtention de dithioesters, thioamides, thiolactames
TL;DR: In this article, a composite catalyst consisting of cesium salt of 12-molybdophosphoric acid and a vanadium promoter, Cs2.5H0.5PMo12O40 + 2 VO2+.
TL;DR: An in vitro system of autotropic synthesis of activated acetic acid from14CO2 in Methanobacterium thermoautotrophicum was developed and the product studied in vitro was acetyl CoA, which involves intermediates of CO2 reduction to methane.