Showing papers on "Carbonic acid published in 1999"

Molded article of biodegradable cellulose acetate and filter plug for smoking article

Abstract: A molded article molded from a cellulose acetate composition comprising, contained in cellulose acetate, a composite material of a decomposition accelerating agent formed of at least one compound selected from the group consisting of oxygen acid of phosphorus, oxygen acid of sulfur, oxygen acid of nitrogen, a partial ester or hydrogen salt of these oxygen acids, carbonic acid and its hydrogen salt, a sulfonic acid and a carboxylic acid, with a reaction controlling agent formed of at least one compound selected from the group consisting of a nitrogen-containing compound, a hydroxy compound, an oxygen-containing heterocyclic compound and a sulfur-containing heterocyclic compound.

Method and apparatus for extracting and sequestering carbon dioxide

Abstract: A method and apparatus to extract and sequester carbon dioxide (CO2) from a stream or volume of gas (112a) wherein said method and apparatus hydrates CO2, and reacts the resulting carbonic acid (144) with carbonate (152). Suitable carbonates include, but are not limited to, carbonates of alkali metals and alkaline earth metals, preferably carbonates of calcium and magnesium. Waste products are metal cations and bicarbonate in solution (146), providing an effective way of sequestering CO2 from a gaseous environment.

Trihydroxycarbenium Hexafluorometalates: Salts of Protonated Carbonic Acid.

Abstract: Stabilization by salt formation: carbonic acid, which is not available as a pure substance, was isolated in the form of its trihydroxycarbenium salts, C(OH)3+ MF6- (M=As, Sb), from the reaction of carbonic acid bis(trimethylsilyl) ester in the superacids HF/MF5 . The structure of the cation is shown in the picture. The ion was also characterized by vibrational spectroscopic studies.

Spectroscopic measurement of the acid dissociation constant of 2-naphthol and the second dissociation constant of carbonic acid at elevated temperatures

Abstract: 2-Naphthol can be used to measure the pH of aqueous solutions if the acid dissociation constant for 2-naphthol is known at a given temperature. The temperature dependence of the acid dissociation constant for 2-naphthol was spectroscopically determined in borate buffer solutions under vapor-saturated pressure up to 200°C. The result was where T is in Kelvin. The pH of carbonate buffer solutions was measured by obtaining the UV–visible spectra of 2-naphthol and utilized to determine the second dissociation constant of carbonic acid up to 175°C under vapor-saturated pressure. The result was where T is in Kelvin. By using the temperature dependence of the dissociation constant, the isocoulombic reaction was studied. The plot of -log Kisoc against 1/T was approximately linear in the temperature range studied. The linearity can be used to predict the dissociation constant by the extrapolation of -log Kisoc to higher temperatures.

Method for preventing deposits in oil extraction

Abstract: Carboxyl-containing fructans such as carboxymethylinulin can be successfully used to prevent deposition of scale composed of, for example, calcium, barium and strontium salts of sulphuric acid and carbonic acid in oil extraction, in that 0.5 - 200 ppm of a carboxyl-containing fructan that contains 0.3 - 3 carboxyl groups per mono-saccharide unit is incorporated in the process water, in the process equipment or in the oil-containing formation.

Ab initio MO study on the catalytic mechanism in the active site of carbonic anhydrase

Abstract: The catalytic mechanism of a model compound for the active site of carbonic anhydrase and of gas-phase reaction of CO2 with water have been studied by the ab initio molecular orbital method. The model reaction proceeds with two steps. The insertion of carbon dioxide into [Zn(NH3)3(OH)]+ complex takes place first, and then the stabilization of [Zn(NH3)3(HCO3)]+ complex occurs. Two reaction mechanisms are proposed for the formation of HCO3− in CA, and we found two transition states corresponding to the mechanisms. In addition to the stabilization of [Zn(NH3)3(HCO3)]+ complex, the six-centered reaction of [Zn(NH3)3(HCO3)]+ with a water molecule is also studied. According to the result, two mechanisms can be competitive because the difference in activation energy is small. Gas-phase reaction of CO2 with water also proceeds with a similar mechanism. In the first step, the insertion of carbon dioxide and a proton transfer take place simultaneously. Then the stabilization of carbonic acid takes place in the second step. Comparing two reactions, the reaction with zinc complex proceeds with much smaller changes in energy than the uncatalyzed reaction.

The gas-phase acidities of substituted carbonic acids

Abstract: Ab initio molecular orbital methods at the CBS-Q level of theory have been used to study the structure, gas-phase acidities and vibrational spectra of carbonic acid, H 2 CO 3 , and several of its derivatives RCO 2 H (R=F, Cl, NH 2 , H and CH 3 ). Geometry optimizations were performed at the MP2(FC)/6-31G(†) level of theory. The syn forms always are more stable than the anti . The highest gas-phase acidity (1288.5 kJ mol −1 ) has been calculated for chloroformic acid. Carbonic acid is, according to calculated ionizations of the first hydrogen, about 24 kJ mol −1 more acidic than formic acid. The fundamental vibrational frequencies have been computed using the Becke3LYP/6-311+G(d,p) method. The computed vibrational frequencies for formic and acetic acids were on average 2% higher than the observed values.

Use of carbon dioxide and carbonic acid to clean contact lenses

Abstract: Simple, efficacious, easily manufacturable, convenient to use and cost-effective contact lens care cleaning compositions comprising carbon dioxide and carbonic acid as cleansing agents are disclosed. The compositions do not require abrasive agents such as polymeric beads, nor ocularly irritating agents such as enzymes or surfactants in order to effectively clean proteinaceous and nonproteinaceous deposits from the surface of contact lenses. Also disclosed is a one-step cleaning and disinfecting regimen, whereby an effervescent tablet composition capable of generating carbon dioxide and carbonic acid is dissolved in a disinfecting solution or rinsing/disinfecting/storage solution.

Polishing compound and a polishing method for silicon wafer

Abstract: The present invention is a polishing compound comprising a colloidal solution of silicon oxide to which an alkaline component and an acid component are added in order to have a buffering action, wherein said alkali component is a quaternary ammonium whose carbon number per one molecular is smaller than 12, and said acid component is at least one selected from the group composed by carbonic acid, boric acid and silicic acid.

Preparation of cyanoacetic esters

Abstract: Cyanoacetic esters are prepared by reacting a corresponding monochloroacetic ester with hydrogen cyanide in the presence of a base, where the base is a compound selected from the group consisting of tertiary amines, salts of carbonic acid, salts of carbonic acid monoesters, salts of carboxylic acids, amidines, guanidines and aromatic N-heterocyclic compounds.

Non-aqueous electrolyte composition for batteries

Abstract: Disclosed is a non-aqueous electrolyte composition for batteries, which is composed of a mixture of a fluorobenzene component and a carbonic acid ester component in which the volume ratio of the fluorobenzene component to the carbonic acid ester component ranges from 50:50 to 5:95. The non-aqueous electrolyte composition has a significant advantage over electrolyte compositions employing carbonic acid ester solvents only, in terms of low temperature performance, cell life, and high-temperature dischargeability.

Effects of weak acids on cation accumulation, ΔpH and ΔΨ in yeast

Abstract: With glucose as carbon source, as reported by other authors (Conway et al., 1950), yeast cells accumulated large amounts of CO2, carbonic acid, bicarbonate and K+ than when grown with ethanol. The addition of propionic acid to the cells produced an increase in the potassium ion accumulation when cells were incubated with ethanol as substrate, but not when incubated with glucose. In disagreement with Ryan et al. (1971) and Ryan and Ryan (1972), the internal pH of the cells with ethanol was lower than with glucose, eliminating this factor as the limiting factor for potassium accumulation. When the membrane potential difference was estimated, it was found that it was higher with glucose as substrate than with ethanol. In addition, with ethanol the addition of propionic acid produced an increase of the membrane potential, in agreement with the idea of an accumulation of the anions of monoprotic acids, which, being not diffusible, increase the negative membrane potential inside, which can drive the accumulation of larger amounts of monovalent cations. It was also found that the addition of propionic acid to cells incubated with glucose as substrate produced an efflux of CO2 from the cells, so that an exchange of the acid appears to take place. Copyright © 1999 John Wiley & Sons, Ltd.

Comparison of mineral acid pretreatments for sulfide removal

Abstract: To determine water quality effects on groundwater treatment for hydrogen sulfide, the authors compared sulfuric acid (H{sub 2}SO{sub 4}) and carbonic acid for ph adjustment pretreatment in a pilot-scale randomly oriented packed tower. Pretreatment with either H{sub 2}SO{sub 4} or carbon dioxide (CO{sub 2}) to pH 6.0 resulted in > 95% sulfide removal for tower feedwater sulfide concentrations of 2.5 mg/L. However, utilization of H{sub 2}SO{sub 4} for pH adjustment resulted in a loss of alkalinity in the finished water and an increase in sulfur (as sulfate), whereas CO{sub 2} pretreatment preserved alkalinity in the finished water and did not increase sulfur (as sulfate).

Carbonic acid diester, aromatic polycarbonate and facilities, and preparation thereof

Abstract: Aromatic polycarbonate having a reduced discoloration and improved heat stability, hue, etc. is provided by keeping a pressure in a raw material melting vessel and the linear velocity of a gas in a transporting piping in a specific range, keeping the concentration of a nitrogen-containing basic compound in a specific range, recycling a byproduct containing specific amounts of impurities, suppressing the amounts of a nitrogen-containing basic compound, metallic elements and a silicic acid derivative in the carbonic acid diester at specific values or less, prescribing the material quality of the reaction facilities, and/or forming an oxide layer at the inner wall surfaces of the reaction facilities.

Aromatic-aliphatic copolycarbonate and process for producing the same

Abstract: An aromatic-aliphatic copolycarbonate and a process for producing the same which comprises polycondensation of an aromatic dihydroxy compound, such as 1,1-bis(4-hydroxyphenyl)cyclohexane, tricyclo(5.2.1.0 2,6 )decanedimethanol, and a carbonic acid diester in a molten state under heating, wherein the carbonic acid diester has a chlorine content of 20 ppm or lower. The copolycarbonate has improved refractive index, balance of dispersion, and photoelastic constant while retaining high impact resistance, high heat resistance, and excellent hue.

Production of water

Abstract: PROBLEM TO BE SOLVED: To provide a method for producing water, by which water exhibits small half-vale width of 17O-nuclear magnetic resonance signal with good reproducibility. SOLUTION: In a method for producing water being used as drinking water, water for producing cosmetics and pharmaceuticals, brewing water, water for diluting a condensate of juice or the like, raw water is passed through a salt- type ion-exchange resin or a mixed bed of the salt-type and a regenerated-type ion-exchange resins so as to control the half-vale width of 17O-nuclear magnetic resonance signal of water. As the salt-form ion exchange resin, carbonic acid ion-type and/or hydrocarbonic acid ion-type anion exchange resins are preferable. As the raw water, pure water having electrical conductivity of <=10 μS/cm is preferably used.

Supported carbonic acid esters useful as set accelerators and thixotropic agents in cement

Abstract: Cementitious compositions are prepared using a dry, flowable admixture containing an ester of carbonic acid such as propylene carbonate and a solid, particulate support which is non-reactive toward the ester such as silica fume. Such admixtures accelerate the set and increase the thixotropy of unhardened mixtures containing hydraulic cement and water, yet can be readily handled and stored in stable form until ready to be used.

Aromatic polycarbonate resin sheet

Abstract: PROBLEM TO BE SOLVED: To obtain the subject sheet excellent in adhesive property and printing property by regulating a residual catalyst activity index of an aromatic polycarbonate obtained by a melt polymerization of a dihydric phenol and a carbonate ester. SOLUTION: This resin sheet is molded from an aromatic polycarbonate resin (a bisphenol A single polymer as especially preferable) having <=2%, preferably <=1%, more preferably <=0.5% and most preferably <=0.2% residual catalyst activity index and obtained by a melt polymerization of a dihydric phenol and a carbonic acid ester (diphenylcarbonate as preferable). As its production method, the reaction by the melting method is usually an ester interchange reaction of the dihydric phenol with the carbonic acid ester, and performed by mixing the dihydric phenol with the carbonic acid ester in the presence of an inert gas while heating, and distilling off the produced alcohol or phenol.

Stabilizer composition for armoring cable

Abstract: PROBLEM TO BE SOLVED: To improve thermal stability and aging stability by employing natural or synthetic hydrotarcyte and basic calcium-aluminuym-hydroxy-phosphite and/or basic calcium-aluminum-hydroxy carboxylate optically surface-modified with a halogen-containing polymer. SOLUTION: Basic calcium-aluminum-hydroxy-phosphite is expressed by a formula I (wherein 2 y>0, 0 is fatty mono- or poly-functional carbonic acid anion or the like having 1-22 carbon number. A is selected from anion of malooic acid, succinic acid, etc. Further, a stabilizer composition includes, liquid or solid organic or inorganic zinc salt.

Method and apparatus for measurement of concentration of carbonic acid

Abstract: PROBLEM TO BE SOLVED: To obtain a method and an apparatus in which the concentration of carbonic acid in water with the comparatively high concentration of carbonic acid and with little salts other than carbonic acid is measured by a simple operation and quickly during the preparation process of pure water, for cleaning, which is used in a semiconductor-device manufacturing process SOLUTION: In a measuring apparatus 10 for the concentration of carbonic acid, a sample- water introduction pipe 21 which is provided with a hydrogen ion-type strongly acidic cation- exchange resin column 3 and a sample-water flow-rate detection part 4 is provided A dilute- water injection pipe 22 which is provided with a dilute-water flow-rate detection part 6 joining it is provided A conductivity detection part 5 which measures the conductivity of diluted sample water is provided A computing part 7 which computes the concentration of carbonic acid in the sample water on the basis of signals from the two flow-rate detection parts 4, 6 and from the conductivity detection part 5 is provided A display part 8 which displays the computed concentration of the carbonic acid is provided By using the apparatus 10, the concentration of the carbonic acid in the permeated water, in a reverse osmosis membrane device, whose concentration of carbonic acid is high and which contains little salts other than carbonic acid or in treated water in an ultraviolet oxidation device can be measured by a simple operation and quickly in the preparation process of pure water, for cleaning, which is used, eg in a semiconductor-device manufacturing process

Treatment with waste incinerator residues

Abstract: Process for treating residues from the incineration of domestic and industrial waste comprises: (a) treatment with carbonic acid associated with hydraulic classification; (b) chemical treatment in an alkaline medium; and (c) treatment and regeneration of the solutions obtained in steps (a) and (b). Preferably step (a) comprises attrition, dilution and hydraulic classification into fractions smaller and larger than 120 mu m. The attrition and dilution operations are associated with a carbonation operation effected in a saturated carbonic acid solution at pH 4.75-6.5. Step (a) includes treatment of wash water with sulphur compounds, e.g. 2,5-dimercaptothiadiazole or trimercaptotriazine, to remove heavy metals, followed by desalination to obtain recycle water and salts free of heavy metals, which can be used as road salt. Step (b) comprises leaching with a solution containing 120-400 (preferably 240-370) g/l NaOH or KOH, optionally with added H2O2, at 50-100 deg C. The products obtained by hydraulic classification are mixed so that the Ca/silica ratio is 4.8-9.8 and the silica/lime ratio is 6-11. The solids from step (b) are washed and adjusted to pH 7-9 with carbonic acid.

Plastic container receiving carbonic acid ingredient and manufacture thereof

Abstract: PROBLEM TO BE SOLVED: To improve preservability of solution and also discharge the solution without air substitution by forming an internal wall face of a plastic container for receiving solution containing carbonic acid ingredients of an alkali-proof resin and preparing the solution to be received to have a specific pH value and a total carbonic acid ingredient concentration within a specific range. SOLUTION: The plastic container for receiving solution containing carbonic acid ingredients for food or medical use has its internal wall face formed of an alkali-proof resin, preferably a polyolefin based resin. The solution to be received in this container is prepared so that pH is 7.79 or higher and its total carbonic acid ingredient concentration is in a range of 0.1 to 5.00 mol/L. The solution is prepared under regulations that when the total carbonic acid ingredient concentration [C] and pH of the solution (index of hydrogen ion concentration [H+]) satisfy log[C]<=log(3.83×10-4.K1/[H+] when 7.79<=pH<8.95 and log[C]<=log(3.83×10-4.K1/[H+]+log(1+K2/[H+]) when 8.95<=pH<10.22.

Molded article of biodegradable cellulose acetate and filter plug for tobacco

Abstract: PROBLEM TO BE SOLVED: To provide a means for accelerating the biodegradation of cellulose acetate, capable of suppressing the change of a DS value (number of acetyl groups based on a glucose unit skeleton) and the generation of a smell of acetic acid. SOLUTION: This biodegradable cellulose acetate molded article is obtained by containing a complex material of a degradation accelerator consisting of at least one kind of compound selected from the group consisting of an oxygen acid of phosphorus, sulfur or nitrogen, a partial ester or a hydrogen salt of these oxygen acids, carbonic acid and its hydrogen salt, a sulfonic acid and a carboxylic acid, with a reaction regulating agent consisting of at least one kind of compound selected from the group consisting of a nitrogen-containing compound, a hydroxy compound, an oxygen-containing hyterocyclic ring compound and a sulfur-containing hetrocyclic ring compound in a cellulose acetate.

Hydrofluoric acid scavenger

Abstract: The present ivention relates to a non-aqueous electrolyte electrochemical cell such as a double layer capacitor or a battery, which comprises as a hydrofluoric acid scavenging additive a mixture of a salt of oxalic acid and a salt of carbonic acid.

Simulation of CO{sub 2}/H{sub 2}S corrosion using thermodynamic and electrochemical models

Abstract: A comprehensive model has been developed for the computation of corrosion rates of carbon steels in the presence of carbon dioxide, hydrogen sulfide and aqueous brines. The model combines a thermodynamic model that provides realistic speciation of aqueous systems with an electrochemical model for partial cathodic and anodic processes on the metal surface. The partial processes taken into account by the model include the oxidation of iron and reduction of hydrogen ions, water, carbonic acid and hydrogen sulfide. Also, the model includes the formation of iron carbonate and iron sulfide scales and their effect on the rate of general corrosion as a function of temperature and solution chemistry. The model has been verified by comparing calculated corrosion rates with laboratory data under conditions that mayor may not be conducive to the formation of protective scales. Good agreement between the calculated and experimental corrosion rates has been obtained. The model has been incorporated into a program that makes it possible to analyze the effects of various conditions such as temperature, pressure, solution composition or flow velocity on corrosion rates.

Production of carbonic acid spring

Abstract: PROBLEM TO BE SOLVED: To improve the efficiency of dissolving carbonic acid gas by employing a porous body having porosity and the aperture diameter in the surface within respectively defined ranges as an aeration means in the case carbonic acid spring is produced by releasing carbonic acid gas as bubbles by an aeration means in hot water supplied to a carbonic acid gas-dissolving apparatus and dissolving carbonic acid gas in the hot water SOLUTION: At the time of producing carbonic acid spring capable of warming a person who takes a bath, an inlet valve 10 of a carbonic acid gas dissolving apparatus 1 is opened and an outlet valve 12 is closed to store a prescribed amount of hot water in the carbonic acid gas dissolving apparatus 1 and after that, the inlet valve 10 is closed and carbonic acid gas in a carbonic acid gas bomb 5 is aerated for a prescribed period by an aeration means and dissolved in the hot water in the dissolving apparatus 1 to produce carbonic acid spring The obtained carbonic acid spring is introduced into a bathtub 9 by opening a valve 12 in the flow outlet of the carbonic acid spring The aeration means is made of a porous body having porosity of 5-70% and aperture diameter in the surface of 001-10 μm and installed in the aeration part and the material for the porous body is preferably a porous hollow fiber membrane, especially preferably a bundle of a large number of porous hollow fiber membranes