Showing papers on "Acetic acid published in 1982"
TL;DR: It is concluded that the feruloylation of cell-wall polymers is not a random process, but occurs at very specific sites, probably on the arabinogalactan component of pectin.
Abstract: 1. Cell walls from rapidly growing cell suspension cultures of Spinacia oleracea L. contained ferulic acid and p-coumaric acid esterified with a water-insoluble polymer. 2. Prolonged treatment with trypsin did not release may feruloyl esters from dearabinofuranosylated cell walls, and the polymer was also insoluble in phenol/acetic acid/water (2:1:1, w/v/v). 3. Treatment of the cell walls with the fungal hydrolase preparation ‘Driselase’ did liberate low-Mr feruloyl esters. The major esters were 4-O-(6-O-feruloyl-beta-D-galactopyranosyl)-D-galactose and 3?-O-feruloyl-alpha-L-arabinopyranosyl)-L-arabinose. These two esters accounted for about 60% of the cell-wall ferulate. 4. It is concluded that the feruloylation of cell-wall polymers is not a random process, but occurs at very specific sites, probably on the arabinogalactan component of pectin. 5. The possible role of such phenolic substituents in cell-wall architecture and growth is discussed.
346 citations
TL;DR: In this article, the acidogenic dissimilation at 30°C of a 1% glucose containing medium (C-limited), the maximum specific growth rate and product distribution, was studied over the pH range from 4.5 to 7.9.
305 citations
TL;DR: In this paper, cyclic olefins and allylbenzene with Rh2(OAc)4 in acetic acid in the presence of t-BuOOH gave the corresponding enones and allylic acetates.
Abstract: Treatment of some cyclic olefins and allylbenzene with Rh2(OAc)4 in acetic acid in the presence of t-BuOOH gave the corresponding enones and allylic acetates, the former being predominant. Applicat...
155 citations
TL;DR: In this article, it was concluded that the reaction proceeded through the route (1) 2CH3OH → HCOOCH3 + 2H2 (2) HCOO CH3 + H2O → HCCOH + CH3OH (3) HCOH → C02+H2 in which no carbon monoxide took part.
134 citations
Patent•
07 Jan 1982
TL;DR: In this article, it was shown that the greater part of the acetic acid reacts with the methanol present to give methyl acetate, and the bottom fraction consisting of small quantities of water, acetic acids and the catalyst.
Abstract: Ethanol is produced continuously via the carbonylation of methanol, by (a) carbonylating methanol, in a reactor R, in the presence of a carbonyl complex of a metal of group VIII of the periodic table and of a halogen compound, (b) separating, in a distillation column D1, the reactor discharge, into a top fraction comprising methyl acetate, methanol, dimethyl ether and an organohalogen compound, and into a bottom fraction comprising water, small quantities of acetic acid and the catalyst, if the latter is not in a fixed bed, the residence time being so adjusted that the greater part of the acetic acid reacts with the methanol present to give methyl acetate, (c) separating the top fraction from D1, in a distillation column D2, into a top fraction comprising small quantities of methyl acetate, methanol, dimethyl ether and the organo-halogen compound, and a bottom fraction comprising methyl acetate and methanol, and recycling the top fraction to reactor R, (d) distilling off, via the top of distillation column D3, the greater part of the water from the bottom fraction from D1and removing this water from circulation, and recycling to reactor R the bottom fraction consisting of small quantities of water, acetic acid and the catalyst, (e) using hydrogen to hydrogenate, in the hydrogenation reactor H, the bottom fraction from D2, in a conventional manner, to give a mixture of methanol and ethanol, and (f) separating the mixture into ethanol and methanol in a distillation column D4, and recycling the methanol to reactor R.
133 citations
TL;DR: When the methanogenic substrates acetic acid or H(2)/CO(2) were added to the digestor on a continuous basis, the microflora were able to adapt and convert them to terminal products while continuing to degrade animal waste to the same extent as without additions.
Abstract: An anaerobic mesophilic digestor was operated using beef cattle waste (diluted to 5.75% volatile solids) as substrate; retention time was 10 days with daily batch feed. Volatile solids destruction was 36%. Daily gas production rate was 1.8 liters of gas (standard temperature and pressure) per liter of digestor contents (0.99 liters of CH(4) per liter of digestor contents). Acetate turnover was measured, and it was calculated that 68% of the CH(4) was derived from the methyl group of acetate. When the methanogenic substrates acetic acid or H(2)/CO(2) were added to the digestor on a continuous basis, the microflora were able to adapt and convert them to terminal products while continuing to degrade animal waste to the same extent as without additions. The methanogenic substrates were added at a rate at least 1.5 times the microbial production rate which was measured in the absence of added substrates. Added acetate was converted directly to CH(4) by acetoclastic methanogens; H(2) addition greatly stimulated acetate production in the digestor. A method is described for the measurement of acetate turnover in batch-fed digestors.
121 citations
Patent•
26 Apr 1982TL;DR: In this paper, the authors proposed a process for the production of high purity methyl acetate from methanol and glacial acetic acid. But the process requires a single reactive distillation column in the presence of an acidic catalyst which is preferably sulfuric acid.
Abstract: The present invention provides a process for the production of high purity methyl acetate from methanol and glacial acetic acid wherein the acetic acid functions both as a reactant and as an extractive agent The process comprises countercurrently flowing approximately stoichiometric quantities of acetic acid and methanol through a single reactive distillation column in the presence of an acidic catalyst which is preferably sulfuric acid The column provides intimate contact between the acetic acid and the methanol and between the acetic acid and the azeotropes (methyl acetate/water and methyl acetate/methanol) which are formed in the column At preferred catalyst concentrations, the residence time in the column is at least about two hours The process further comprises continuously removing high purity methyl acetate from the top of the column and continuously removing water from the bottom of the column In preferred embodiments, the process further comprises removing intermediate boiling compounds, such as methyl propionate, methyl butyrate, isopropyl acetate, and mixtures thereof, from a vapor sidedraw stream The invention further comprises in preferred embodiments the use of a temperature control scheme whereby the overhead and the bottoms compositions are controlled by using two temperature control loops
109 citations
TL;DR: The bioconversion of sugars present in wood hemicellulose to 2,3-butanediol by Klebsiella pneumoniae grown on high initial concentrations of sugars was investigated and the concentration of end products normally found at the termination of fermentation was shown to be noninhibitory to growth and substrate utilization.
Abstract: The bioconversion of sugars present in wood hemicellulose to 2,3-butanediol (hereafter referred to as butanediol) by Klebsiella pneumoniae grown on high initial concentrations (up to 10%) of sugars was investigated. Initial fermentation studies with a chemically defined medium suggested that sugar levels in excess of 2% could not be utlized even when a higher inoculum size (5 to 10%) was used. The addition of nutrient supplements, viz., yeast extract, urea, ammonium sulfate, and trace elements resulted in a 10 to 50% increase in butanediol yields, although sugar utilization remained incomplete. The concentration of end products normally found at the termination of fermentation was shown to be noninhibitory to growth and substrate utilization. Acetic acid was inhibitory at concentrations above 1%, although growth and butanediol yield were stimulated in cultures supplemented with lower levels of acetic acid. The efficient utilization of 4% substrate concentrations of d-glucose and d-xylose was achieved, resulting in butanediol yields of 19.6 and 22.0 g/liter, respectively.
97 citations
TL;DR: In this paper, the authors used liquid membrane emulsions to extract phenolic compounds and organic acids from their aqueous solutions and found that more than 99% of the compounds can be extracted in less than 1 minute.
94 citations
91 citations
TL;DR: In this article, the effects of mixing and volatile fat acid concentrations on anaerobic digestion was reviewed and results of further experiments, carried out on laboratory scale digesters, reported.
TL;DR: In this paper, the analysis of uronic acids such as d-galacturonic acid, d-glucuronic acids, d - mannuronic amino acid and l -guluronic acyclic acid by high performance liquid chromatography was studied.
TL;DR: In this paper, the formation of methane from organic compounds greater than C$\_2$ in chain length requires a mixture of methanogenic and chemoheterotrophic non-methanogenic bacteria.
Abstract: The microbial formation of methane from organic compounds greater than C$\_2$ in chain length demands a mixture of methanogenic and chemoheterotrophic non-methanogenic bacteria. The chemoheterotrophic, non-methanogens initiate the reactions by well established pathways, hydrolysing complex polymers and fermenting the unit constituents to smaller end-product molecules, which are further metabolized by other chemoheterotrophs to acetic acid, H$\_2$ and CO$\_2$. The methanogens are essential physiological partners in the overall conversion of the initial substrates to this level because they oxidize H$\_2$ and reduce CO$\_2$ to form methane. The ultimate formation of acetate as the chief intermediate in this fermentation depends on the removal of H$\_2$ by the methanogens. Otherwise, these acetogenic reactions are not thermodynamically feasible. Acetate, the major precursor of CH$\_4$ in fermentation systems, is converted to CH$\_4$ and CO$_2$ via a unique aceticlastic reaction. Examples of microbial partnerships producing methane from the fermentation of organic compounds are described.
TL;DR: Clostridium thermoaceticum is apparently more sensitive to free acetic acid than to either acetate ion or pH, and it was shown that the redox potential must be at least as low as -300 and -360 mV, respectively, for growth to occur.
Abstract: Four strains of the homofermentative, obligately anaerobic thermophile Clostridium thermoaceticum were compared in pH-controlled batch fermentation for their tolerance to acetic acid, efficiency of converting glucose to acetic acid and cell mass, and growth rate. At pH 6 (and pH 7) and initial acetic acid concentrations of less than 10 g/liter, the four strains had mass doubling times of 5 to 7 h and conversion efficiencies to acetic acid and cell mass of about 90% (70 to 110%) and 10%, respectively. At pH 6 and initial acetic acid concentrations of greater than 10 g/liter, only two of the strains grew, the mass doubling time increased to 18 h, and the conversion efficiencies to acetic acid and cell mass remained unchanged. Both of these strains had been selected for their ability to grow in the presence of acetate at neutral pH. The highest acetic acid concentrations reached were about 15 and 20 g/liter at pH 6 and 7, respectively. C. thermoaceticum is apparently more sensitive to free acetic acid than to either acetate ion or pH. It was also shown that, at pH 6 and 7, the redox potential must be at least as low as −300 and −360 mV, respectively, for growth to occur.
TL;DR: In this article, the herbicides 2,4-D and dichlobenil were individually incorporated into 1.6-2.8mm alginate gel beads by using calcium chloride and barium chloride as gellants.
Abstract: The herbicides 2,4-D[(2,4-dichlorophenoxy)acetic acid] and dichlobenil (2,6-dichlorobenzonitrile) were individually incorporated into 1.6–2.8-mm alginate gel beads by using calcium chloride and barium chloride as gellants. The release rate of each herbicide from the beads into water was greatly influenced by drying and the choice of gellant cation. Slowest release was obtained with dried samples that were gelled with barium chloride. At the slowest rates, release of 2,4-D was complete in 14 days, while only 59% of the less-soluble dichlobenil was released in 150 days.
TL;DR: This article corrects the article on p. 118 in vol.
Abstract: Using a series of pH controlled batch fermentations operated in a fed-batch mode and adaptation and selection techniques where pH and acetic acid provided the selective pressures, we isolated a culture of Clostridium thermoaceticum that can grow and produce acetic acid at pH 4.5. At pH 4.5 the fastest mass doubling time was 36 h, and the highest acetic acid concentration reached was 4.5 g/liter. Generally, as the pH was decreased from 6.0 and the initial acetic acid concentration increased, the mass doubling time increased, and the final acetic acid concentration decreased. These observations can be explained in terms of inhibition by the free acetic acid concentration at a given pH, relative to the total acetic acid concentration (free acid plus acetate ion). We have thus reached one of the criteria determined by us to be required for an economically viable fermentation acetic acid process, i.e., pH 4.5. A second requirement for a mass doubling time of about 7 h (0.1/h dilution rate) can probably be reached by selection in continuous culture. The final requirement for an acetic acid concentration of 50 g/liter will be the most difficult to achieve in view of the organism's sensitivity to low concentrations ofmore » free acetic acid. (Refs. 4).« less
TL;DR: It was concluded that cellulose could be degraded continuously in a system with C. thermocellum for production of ethanol, and the continuous system like the batch method is feasible, but may not be promising as yet because of the slow generation time of this microorganism.
Abstract: The feasibility of producing ethanol in a continuous system from cellulose using Clostridirrrn thermocellum was investigated. This anaerobic and therniophilic bacterium was able to degrade cellulose directly into ethanol with acetic acid, hydrogen. and carbon dioxide as by-products of this fermentation. The fermentation was first carried out in a batch mode to study the effects of buffers, temperature, and agitation on microbial growth and ethanol production. From the compounds used to control pH. sodium bicarbonate had the most preferred effects on generation time and ethanol production. As expected, there was a positive relationship between temperature and growth rate. On the other hand, agitation did not benefit from ethanol production or microbial growth. The possibility of noncompetitive inhibition within such a system was deduced from the calculation of the kinetic constants K(m) and V(max). Continuous fermentations were carried out at 60 degrees C and pH 7.0 using 1.5 and 3% pure cellulose as a limiting substrate. The maximum ethanol concentration reached during the 1.5% cellulose fermentation was 0.3%. and 0.9% during the 3% cellulose fermentation. The yield of ethanol was about 0.3 grams per gram of consumed cellulose. The overall yield in both schemes was around 0.45 and 0.75 grams per gram of cellulose degraded. It was concluded that cellulose could be degraded continuously in a system with C. thermocellum for production of ethanol. While the continuous system like the batch method is feasible, it may not be promising as yet because of the slow generation time of this microorganism.
TL;DR: Proteolysis in cocoa seeds was studied by fermentation-like anaerobic incubation to determine whether post-mortem proteolysis depends only on temperature and acidity as mentioned in this paper, which is not dependent on microorganisms, on exudation or on interaction of proteins and polyhydroxyphenols.
Abstract: Proteolysis in cocoa seeds was studied by fermentation-like anaerobic incubation to determine whether post-mortem proteolysis depends only on temperature and acidity. In acetone dry powder incubation, autolytic release of α-amino nitrogen is optimal at pH 4.0-4.5 and is higher at 55°C than at 45°C. Proteolysis increases with acidification. However, in seed and seed fragment incubation, acetic acid is more effective than citric acid under similar conditions. Further, a first incubation at a low temperature (40°C) in contrast to a high temperature (50°C) favours post-mortem proteolysis during a subsequent incubation of cotyledon tissue at 50°C in an acetic solution, whereas it does not with cotyledon dry powder in the same solution. This effect of pre-incubation temperature in seeds is diminished in the presence of a high concentration of acetic acid. It does not depend on microorganisms, on exudation or on interaction of proteins and polyhydroxyphenols. Since increased proteolysis after incubation at 40°C correlates with structural changes in protein vacuoles and with water uptake by the intact seeds, a causal relationship is indicated.
TL;DR: A thermophilic strain, No. 1023, of Acetobacter aceti was isolated, by which it became possible to carry out submerged vinegar production at 35°C, and a plasmid, pTA 5001, seemed to have no direct connection with acetic acid resistance or ethanol oxidizing ability.
Abstract: A thermophilic strain, No. 1023, of Acetobacter aceti was isolated, by which it became possible to carry out submerged vinegar production at 35°C. The thermophilic property of the strain correlated closely with its acetic acid resistance. Strain No. 1023 lost acetic acid resistance at high frequency (more than 55% in isolated strains) and lost ethanol oxidizing ability at lower frequency (about 40%) compared to the above in the stationary growth phase in a liquid medium containing ethanol. The loss of these properties during the stationary phase was confirmed using a genetically marked strain (pro−) of No. 1023. Such frequent loss of acetic acid resistance and ethanol oxidizing ability suggested a relationship between these properties and a plasmid. A plasmid, pTA 5001, was found in strain No. 1023, and its molecular weight was determined to be 17 × 106 daltons by electron microscopy. The plasmid, however, seemed to have no direct connection with acetic acid resistance or ethanol oxidizing ability, becaus...
TL;DR: Using a simple mathematical model, it was shown that oxygen transfer in the microbial film controls the reactor productivity.
Abstract: The immobilization of living Acetobacter cells by adsorption onto a large-surface-area ceramic support was studied in a pulsed flow reactor. The high oxygen transfer capability of the reactor enabled acetic acid production rates up to 10.4 g L(-1) h(-1) to be achieved. Using a simple mathematical model incorporating both internal and external mass transfer coefficients, it was shown that oxygen transfer in the microbial film controls the reactor productivity.
TL;DR: High pK' acids (such as acetic, as well as propionic and butyric) can provide a buffering system (acetate-acetic acid) capable of countering the pH decrement generated by the low pK’ acids (lactic, formic and pyruvic).
Abstract: The authors conducted a comparative study of plaque acids in three-day fasting or resting plaque samples from ten pairs of caries-resistant (CR) and caries-susceptible (CS) subjects chewing a sucrose gum for a period of 45 min. The study disclosed two important differences: 1) The amount and rate of production of lactic acid were lower in the CR group, especially at ten min; and 2) in contrast to lactic acid levels, the level of acetic acid was significantly higher in the CR group at zero time (before chewing), and after 20 and 45 min of chewing the sucrose gum. Both the lower levels of lactic acid and the higher levels of acetic acid are (paradoxically) consistent with the higher plaque pH values reported for CR when compared to CS subjects. High pK' acids (such as acetic, as well as propionic and butyric) can provide a buffering system (acetate-acetic acid) capable of countering the pH decrement generated by the low pK' acids (lactic, formic and pyruvic).
TL;DR: Palladium-catalyzed oxidation of 1,3-dienes in acetic acid in the presence of LiCl and LiOAc produces 1-acetoxy-4-chloro-2-alkenes in high selectivity as discussed by the authors.
TL;DR: In this paper, the selectivities of competitive alkali metal transport into toluene by 2-((sym-dibenzo-16-crown-5)oxyl)-decanoic acid and (sym-bis(4(5)-tert-butylbenzo)-16-(crown)-5)oxy)acetic acid are determined in solvent extraction, bulk liquid membrane transport, and liquid surfactant membrane transport (waterin-oil-in-water emulsion).
Abstract: Efficiencies and selectivities of competitive alkali metal transport into toluene by 2-((sym-dibenzo-16-crown-5)oxyl)-decanoic acid and (sym-bis(4(5)-tert-butylbenzo)-16-crown-5)oxy)acetic acid are determined in solvent extraction, bulk liquid membrane transport, and liquid surfactant membrane transport (water-in-oil-in-water emulsion) and compared with those previously measured for solvent extraction and bulk liquid membrane transport with chloroform as the organic phase. 4 figures, 2 tables.
TL;DR: In this paper, the treatment of several cyclic olefins, β-pinene, allylbenzene, and estragole with palladium(II) salt in acetic acid in the presence of t-butyl hydroperoxide and tellurium(IV) oxide afforded mainly the corresponding allylic acetates.
Patent•
19 Jul 1982TL;DR: In this article, the process for the co-production of carboxylic acids of the general formula R 1 -COOR 2 and R 2 -COOH and R 3 OR 4 (R 1, R 2, R 3, R 4 representing (substituted) alkyl, aryl, alkaryl, or aralkyl) was described.
Abstract: Process for the co-production of carboxylic acids of the general formula R 1 --COOH and R 2 --COOH and carboxylic acid esters of the general formula R 1 --COOCH 2 R 2 and R 2 --COOCH 2 R 1 from carboxylic acid esters of the general formula R 1 --COOR 2 and/or ethers of the general formula R 3 OR 4 (R 1 , R 2 , R 3 , R 4 representing (substituted) alkyl or (substituted) aryl, alkaryl or aralkyl, R 1 also representing H), carbon monoxide and hydrogen at elevated temperature and pressure in the presence of a ruthenium compound, a further Group VIII metal compound, and a compound R 5 Hal or R 5 COHal where R 5 has one of the meanings given for R 2 and Hal is iodine or bromine, the reaction mixture being substantially free from other transistion metal or Group II metal iodides or bromides, and containing a trivalent nitrogen compound containing a group ##STR1## (X=O or S), such as an amide, a carbamate, a urea or a derivative thereof. The process is of special interest for the selective conversion of methyl acetate into ethyl acetate and acetic acid at pressures well below 100 bar.
TL;DR: It is shown that a concentration gradient persists in whole seeds for most of the time required for fermentation, because of the slow diffusion of acetic acid.
Abstract: Characteristic post-mortem changes in subcellular structures are described which are caused by the penetration of acetic acid during incubation of cocoa seeds in aqueous media. In the storage cells lipid is agglomerated and separates from hydrophilic portions in proportion to the acetic acid concentration and pH. This effect is less pronounced at 50°C than at 40°C. In the absence of acetic acid or with very low concentration of undissociated acetic acid other substructural characteristics dominate in most of the cells. At 50°C Post-mortem changes do not induce lipid agglomeration. At 40°C the intact protein vacuole swells and its matrix structure becomes spongy as a response to in-vivo water absorption. Finally, it is shown that a concentration gradient persists in whole seeds for most of the time required for fermentation, because of the slow diffusion of acetic acid. The results are compared with temperature effects on subcellular structures and are discussed in relation to their significance for proteolysis in cocoa seeds during fermentation.
TL;DR: The results showed that the cuticles collagen and collagen sonicates had identical values of persistence length and that the neutral salt effect for the cuticle collagen was far smaller than that for DNA.
Abstract: The persistence length of lugworm cuticle collagen in 0.1M acetic acid was evaluated as 1600 ∼ 1800 A by Yamakawa-Fujii's model for a wormlike chain from the sedimentation constant and the intrinsic viscosity. The persistence length was further examined for a series of sample “collagen sonicates” produced by varying the duration of sonic irradiation. To estimate the salt effect on the persistence length, measurements were made over a range of NaCl concentrations from 0 to 0.1M. The results showed that the cuticle collagen and collagen sonicates had identical values of persistence length and that the neutral salt effect for the cuticle collagen was far smaller than that for DNA.
TL;DR: In this article, four stereoisomers of 6-amino-6-deoxyheptonic acid, having the l-glycero-d-galacto (1), d-glocco-dgluco (2), l-gloglocco -d-glucocco (3), and d-glycocococco −d-glucco (4) configurations, were synthesized from D-Galacto-and D-Gluco-dialdose derivatives, respectively.
Patent•
05 Apr 1982
TL;DR: In this article, the authors describe the production of malonic acid dialkyl esters by reacting halogen acetic acid alkyls with carbon monoxide, and a solution of alkali metal hydroxide in an alcohol at pH of up to 8.5 in the presence of a cobalt compound which is a catalyst for the reaction.
Abstract: Production of malonic acid dialkyl esters by reacting halogen acetic acid alkyl ester with carbon monoxide, and alkali metal alcoholate, alkaline earth metal alcoholate or a solution of alkali metal hydroxide in an alcohol at a pH of up to 8.5 in the presence of a cobalt compound which is a catalyst for the reaction.
TL;DR: In this paper, the 17O-NMR was used to measure the chemical shifts of the enriched amino acids glycine, aspartic acid and glutamic acid in aqueous solution as a function of pH.
Abstract: The 17O-NMR. chemical shifts of the enriched amino acids glycine, aspartic acid and glutamic acid were measured in aqueous solution as a function of pH. High magnetic fields are necessary to resolve the α, β- and α, γ-carboxyl resonances of aspartic acid and glutamic acid, respectively. The chemical shifts of acetic acid were measured for comparative reasons. Ionization constants and titration shifts were obtained by nonlinear least-squares fits to one-proton titration curves. The average excitation energy approximation is discussed in terms of the observed changes in 17O-shielding on deprotonation. No intramolecular association between the α-amino group and the α-carboxyl group in the zwitterionic form is required to explain the high-frequency shift of the carboxylate ion. Also no indication of an intramolecular association between the α-amino group and the side-chain carboxyl groups of aspartic acid or glutamic acid was found.