Showing papers on "Carbonic acid published in 2006"
TL;DR: This work indicates that the relatively high native concentration of + (large KW), which has commonly been thought to lead to the occurrence of acid-catalyzed reactions in HTW without added catalyst, does not explain the dehydration of 1,4-butanediol inHTW without catalyst, and H2O serves directly as the proton donor for the reaction.
Abstract: We conducted an experimental investigation into the kinetics and mechanism of tetrahydrofuran synthesis from 1,4-butanediol via dehydration in high-temperature liquid water (HTW) without added catalyst at 200-350 degrees C. The reaction was reversible, with tetrahydrofuran being produced at an equilibrium yield of 84% (at 200 degrees C) to 94% (at 350 degrees C). The addition of CO2 to the reaction mixture increased the reaction rate by a factor of 1.9-2.9, because of the increase in acidity resulting from the formation and dissociation of carbonic acid. This increase was much less than that expected (factor of 37-60) from a previously suggested acid-catalyzed mechanism. This disagreement prompted experiments with added acid (HCl) and base (NaOH) to investigate the influence of pH on the reaction rate. These experiments revealed three distinct regions of pH dependence. At high and low pH, the dehydration rate increased with increasing acidity. At near-neutral pH, however, the rate was essentially insensitive to changes in pH. This behavior is consistent with a mechanism where H2O, in addition to H+, serves as a proton donor. This work indicates that the relatively high native concentration of + (large KW), which has commonly been thought to lead to the occurrence of acid-catalyzed reactions in HTW without added catalyst, does not explain the dehydration of 1,4-butanediol in HTW without catalyst. Rather, H2O serves directly as the proton donor for the reaction.
109 citations
TL;DR: Strong hydration of carbonate in aqueous solution could be detected by Raman spectroscopy and the hydrogen bonds between carbonates in heavy water are stronger than the ones in normal water.
Abstract: Raman spectra of CO(2) dissolved in water and heavy water were measured at 22 degrees C, and the Fermi doublet of CO(2), normally at 1285.45 and 1388.15 cm(-1) in the gaseous state, revealed differences in normal water and heavy water, although no symmetry lowering of the hydrated CO(2) could be detected. Raman spectra of crystalline KHCO(3) and KDCO(3) were measured at 22 degrees C and compared with the infrared data from the literature. In these solids, (H(D)CO(3))(2)(2-) dimers exist and the spectra reveal strong intramolecular coupling. The vibrational data of the dimer (C(2h) symmetry) were compared with the values from density functional theory (DFT) calculations and the agreement is fair. Careful measurements were made of the Raman spectra of aqueous KHCO(3), and KDCO(3) solutions in D(2)O down to 50 cm(-1) and, in some cases, down to very low concentrations (> or =0.0026 mol/kg). In order to complement the spectroscopic assignments, infrared solution spectra were also measured. The vibrational spectra of HCO(3)(-)(aq) and DCO(3)(-)(D(2)O) were assigned, and the measured data compared well with data derived from DFT calculations. The symmetry for HCO(3)(-)(aq) is C(1), while the gas-phase structure of HCO(3)(-) possesses Cs symmetry. No dimers could be found in aqueous solutions, but at the highest KHCO(3) concentration (3.270 mol/kg) intermolecular coupling between HCO(3)(-)(aq) anions could be detected. KHCO(3) solutions do not dissolve congruently, and with increasing concentrations of the salt increasing amounts of carbonate could be detected. Raman and infrared spectra of aqueous Na(2) -, K(2) -, and Cs(2)CO(3) solutions in water and heavy water were measured down to 50 cm(-1) and in some cases down to extremely low concentrations (0.002 mol/kg) and up to the saturation state. For carbonate in aqueous solution a symmetry breaking of the D(3h) symmetry could be detected similar to the situation in aqueous nitrate solutions. Strong hydration of carbonate in aqueous solution could be detected by Raman spectroscopy. The hydrogen bonds between carbonate in heavy water are stronger than the ones in normal water. In sodium and potassium carbonate solutions no contact ion pairs could be detected even up to the saturated solutions. However, solvent separated ion pairs were inferred in concentrated solutions in accordance with recent dielectric relaxation spectroscopy (DRS) measurements. Quantitative Raman measurements of the hydrolysis of carbonate in aqueous K(2)CO(3) solutions were carried out and the hydrolysis degree a was determined as a function of concentration at 22 degrees C. The second dissociation constant, pK(2), of the carbonic acid was determined to be equal to 10.38 at 22 degrees C.
106 citations
TL;DR: In this article, it was demonstrated that the aragonite water fractionation factor is independent of the pH of the parent solution and equal to: 1000lnaðaragonite-H2OÞ ¼ 29:12 � 0:09.
78 citations
TL;DR: In this article, the CO 2 flux was correlated well with the salinity and negatively with the volume of the brine in the upper part of the sea-ice, which suggested the larger role of the difference in partial pressure of CO 2 between brine and air as compared to that of competitive change in the volume.
Abstract: In order to clarify the CO 2 exchange between the seawater and the overlying air during the sea-ice formation, we have carried out tank experiments in a low-temperature room. CO 2 concentration above the sea-ice began to increase since the beginning of the sea-ice formation, and increased at larger rates with time and the decrease in air temperature. This increase of CO 2 concentration in air was mainly caused by the increase in dissolved inorganic carbon concentration in the brine of the upper part of sea-ice, changes in CO 2 solubility and dissociation constants of carbonic acid. The CO 2 flux increased logarithmically with time, and reached a level of 2 × 10 −4 to 5 × 10 −4 g-C m −2 hr −1 at 50 mm ice thickness. We found that the CO 2 flux was correlated well with the salinity and negatively with the volume of the brine in the upper part of the sea-ice. These suggested the larger role of the difference in partial pressure of CO 2 between brine and air as compared to that of competitive change in the brine volume. Present results suggest the necessity to examine the CO 2 exchange between the seawater and air in seasonal sea-ice areas. DOI: 10.1111/j.1600-0889.2006.00204.x
73 citations
TL;DR: In this paper, a model was developed to allow the pH profile of an aqueous phase, undergoing a sudden application of bubbles containing carbon dioxide, to be used as a measure of the transient dissolved carbon dioxide concentration in a reactor.
Abstract: Carbon dioxide can serve as a source of carbon for photosynthetic cell cultures, but it must reside in the aqueous phase prior to uptake. Carbon dioxide is a gas at room temperature and pressure, and its solubility in water is very low. It resides in the aqueous phase as four different species, carbon dioxide, CO2; carbonic acid, H2CO3; bicarbonate ion, HCO3-; and carbonate ion, CO3=, whose equilibrium concentrations are pH dependent. With these factors taken into account, a model has been developed to allow the pH profile of an aqueous phase, undergoing a sudden application of bubbles containing carbon dioxide, to be used as a measure of the transient dissolved carbon dioxide concentration in a reactor. Experimentally measured carbon dioxide profiles were used to calculate the overall volumetric mass transfer coefficients for carbon dioxide into a well-mixed reactor as a function of temperature, stirring speed, and aeration rate. Finally, an empirical correlation is provided to predict the overall volume...
59 citations
TL;DR: In this article, the elusive monomethyl ester of carbonic acid [CH3OC(O)OH] has been prepared at 300 K by protonation of the sodium salt NaOC (O)OCH3 with anhydrous HCl or water and characterized by 1H- and 13C NMR spectroscopy.
Abstract: The elusive monomethyl ester of carbonic acid [CH3OC(O)OH] has been prepared at 300 K by protonation of the sodium salt NaOC(O)OCH3 with anhydrous HCl or water and characterized by 1H- and 13C NMR spectroscopy. The stability of the acid and its reactivity towards hydroxo ions and methylating agents under ambient conditions are discussed. The energetics and the mechanism of the investigated reactions are examined on the basis of density functional calculations. For kinetic and thermodynamic reasons CH3OC(O)OH is unlikely to be formed by insertion of CO2 into the O–H bond of methanol. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
46 citations
TL;DR: In this paper, the authors show the catalytic use of self-neutralizing acids and compare the reaction rates of several alkyl carbonic acids with diazodiphenylmethane (DDM).
Abstract: Acids are the most common industrial catalysts but have the disadvantage of requiring post-reaction neutralization and salt disposal. We show the catalytic use of self-neutralizing acids. Carbon dioxide interacts with water and amines to form carbonic acid and carbamates. A similar interaction occurs with alcohols to form alkylcarbonic acids. All three solvent systems provide in situ acid formation for catalysis which can be easily neutralized by removal of carbon dioxide. However, water has poor organic solubility and amines form salts so only alkylcarbonic acids combine good organic solubility with simple neutralization via depressurization. The use of in situ acid also completely eliminates the solid salt wastes associated with many acid processes. To elucidate how to implement these systems in place of a standard acid system we compare the reaction rates of several alkylcarbonic acids with diazodiphenylmethane (DDM). We report also the effect of CO2 pressure on reaction rate of DDM as well as measure the dielectric constant of these systems. Finally, a Hammett plot is used to identify the dominant step in alkylcarbonic acid catalysis.
43 citations
Patent•
04 Apr 2006
TL;DR: In this paper, an integrated process combining a first module for capturing and separating CO2 from exhaust gases, with a second module, for exploiting the captured CO2 in the anaerobic digestion of organic matter to produce methane, is provided.
Abstract: A process to provide an alternative to CO2 sequestration in depleted gas or oil fields is presented. An integrated process combining a first module, for capturing and separating CO2 from exhaust gases, with a second module, for exploiting the captured CO2 in the anaerobic digestion of organic matter to produce methane, is provided. In the first module CO2 is removed from the exhaust gas by contact and mass transfer to an alkaline metal solution and more particularly of sodium. The CO2 dissolved in the solution is rapidly hydrated into carbonic acid by means of carbonic anhydrase which is immobilized onto an inert support. Finally, the hydrated CO2 is then reacted with alkaline metal and upon adding alkaline metal carbonate to the solution, a precipitate of alkaline bicarbonate is obtained, which is then calcinated to produce a concentrated flow of CO2. In the second module such concentrated flow of CO2 is used to provide a perfectly suitable environment for the hydrolysis of organic matter and for hydrogen production in distinct and specialized sections aimed at acidification and fermentation respectively; at the same time mixed and high density microbial populations, already there or selectively added to the fermentation process, are being conditioned to utilize CO2 and hydrogen to increase the production of acetates and consequently of methane. The outlined process may be used e.g. by greenhouse gas emitting firms as well as by those involved in organic waste management.
35 citations
TL;DR: A kinetic analysis of the photosynthesis inhibition by buffers allowed quantification of some components of the carbon concentrating mechanism of the brown macroalga Laminaria saccharina, suggesting that the CCM is located mainly on the cell membrane and not in the chloroplast, as suggested for most macroalgae.
Abstract: A kinetic analysis of the photosynthesis inhibition by buffers allowed quantification of some components of the carbon concentrating mechanism (CCM) of the brown macroalga Laminaria saccharina. The CCM was based on the presence of acid regions outside the plasma membrane that increased the CO2 concentration available for photosynthesis by 10–20 times above that of the bulk medium at alkaline pH. Furthermore, the results suggested that the CCM is located mainly on the cell membrane and not in the chloroplast, as suggested for most macroalgae. The degree of dissipation of the acid regions by a buffer was related to the buffer anion concentration (B−), estimated from the titration of the buffer from bulk medium pH to a pH endpoint value close to the first pKa of the carbonic acid system. A kinetic model describing the relationship between inhibition of photosynthesis by a buffer and B− was developed suggesting that buffers act as competitive inhibitors with IC50 (the concentration of the buffer anion which reduces the reaction velocity by half) of 5.0 mol m−3. This model can be used to estimate the inhibitory effect of any buffer on the photosynthesis of L. saccharina. Nevertheless, some buffers tested showed a lower effect than that predicted from the hyperbolic model suggesting that their strength as inhibitors depended on: (1) the pKa in relation to the first pKa of the carbonic acid system and (2) its molecular weight (i.e. its mobility).
34 citations
TL;DR: In this paper, the authors investigated calcite solubility approached from undersaturation in geologically relevant Na-Ca-Mg-Cl synthetic brines at CO2 partial pressures of ∼ 0.0 bar at 25°C.
TL;DR: It is concluded that using brine in a gas-exchange membrane system for capturing CO2 from a gas stream to liquid is technically feasible and can be accomplished at a reasonable expenditure of energy.
Abstract: A laboratory-scale reactor was developed to evaluate the capture of carbon dioxide (CO2) from a gas into a liquid as an approach to control greenhouse gases emitted from fixed sources. CO2 at 5-50% concentrations was passed through a gas-exchange membrane and transferred into liquid media--tap water or simulated brine. When using water, capture efficiencies exceeded 50% and could be enhanced by adding base (e.g., sodium hydroxide) or the combination of base and carbonic anhydrase, a catalyst that speeds the conversion of CO2 to carbonic acid. The transferred CO2 formed ions, such as bicarbonate or carbonate, depending on the amount of base present. Adding precipitating cations, like Ca++, produced insoluble carbonate salts. Simulated brine proved nearly as efficient as water in absorbing CO2, with less than a 6% reduction in CO2 transferred. The CO2 either dissolved into the brine or formed a mixture of gas and ions. If the chemistry was favorable, carbonate precipitate spontaneously formed. Energy expenditure of pumping brine up and down from subterranean depths was modeled. We conclude that using brine in a gas-exchange membrane system for capturing CO2 from a gas stream to liquid is technically feasible and can be accomplished at a reasonable expenditure of energy.
Patent•
19 May 2006
TL;DR: In this paper, a cadaverine carbonate is produced by using lysine carbonates as a substrate, conducting a pH adjustment by the addition of carbon dioxide, and then carrying out an enzymatic decarboxylation of Lysine.
Abstract: A cadaverine carbonate is produced by using lysine carbonate as a substrate, conducting a pH adjustment by the addition of carbon dioxide, and then carrying out an enzymatic decarboxylation of lysine. A dicarboxylic acid salt is added to the resultant cadaverine carbonate, and a cadaverine dicarboxylic acid salt is produced through an isolation step after a salt exchange reaction with carbonic acid. Cadaverine is produced by concentrating a solution of the cadaverine carbonate, to thereby release carbon dioxide out of the system. A polyamide is produced by using the resultant cadaverine dicarboxylic acid salt or cadaverine.
Patent•
19 May 2006
TL;DR: In this paper, the basic copper carbonate produced has the formula: (CuCO 3 ) x (Cu(OH 2 ) y, where y is 1 and x is between 0.5 and 0.95, or where y was 1 and X greater than 1.
Abstract: A basic copper salt selected from basic copper carbonate, basic copper sulfate, basic copper acetate, basic copper citrate, and basic copper nitrate is manufactured by contacting copper metal with an aqueous solution having ammonia; an acid selected from carbonic acid, sulfuric acid, acetic acid, nitric acid, or citric acid; and oxygen, under conditions where the copper metal is converted to the basic copper salt; and then recovering the basic copper salt. The most economical embodiment is where the ammonia is present in the aqueous solution is in an amount between about 6.7 g/l and about 15 g/l calculated as NH 3 , and the pH of the composition is between 8 and 10, and the temperature of the composition is between 25° C. and 100° C. The method is particularly useful if the basic copper salt is basic copper carbonate. The basic copper carbonate produced has the formula: (CuCO 3 ) x (Cu(OH 2 ) y , where y is 1 and x is between 0.1 to less than 1; or where y is 1 and x is 1, or where y is 1 and x is between 0.5 to less than about 0.95, or where y is 1 and x greater than 1.
Patent•
17 May 2006
TL;DR: In this paper, a carbonic acid type high activity partially crystallized calcium phosphate and its preparation is described, which has high bioactivity, reaction activity and biodegradability, and may be used widely in replacing and repairing hard tissue.
Abstract: The present invention is carbonic acid type high activity partially crystallized calcium phosphate and its preparation The material has the nonstoichiometric crystallization state between the crystal and amorphous substance and contains carbonate radical, Mg, Sr and Zn essential for human body bone tissue It is prepared with water soluble phosphate and calcium salt as material and through adding carbonate, Sr salt and/or Mg salt and/or Zn salt, reaction in water solution, separating, drying and calcining reaction product to obtain carbonic acid type high activity partially crystallized calcium phosphate powder The powder has high bioactivity, reaction activity and biodegradability, and may be used widely in replacing and repairing hard tissue
Patent•
20 Jul 2006
TL;DR: In this article, a synthetic method of cyclic carbonate with water system was proposed, which is characterized in that: in the water system with water content 0 per cent to 60.0 per cent of the weight of the epoxy compound and water, the ionic liquid with double teeth and alkali metal salt (capable of excluding) are used as the catalysts during reaction and the cyclic dioxide is synthesized under the condition of reaction pressure of 0.1MPa to 10.0MPa, temperature of 313.15K to 483.15
Abstract: The invention relates to a synthetic method of the cyclic carbonate with water system, which is characterized in that: in the water system with water content 0 per cent to 60.0 per cent of the weight of the epoxy compound and water, the epoxy compound and the carbon dioxide work as the raw materials and the ionic liquid with double teeth and alkali metal salt (capable of excluding) are used as the catalysts during reaction and the cyclic carbonate is synthesized under the condition of reaction pressure of 0.1MPa to 10.0MPa, temperature of 313.15K to 483.15K and the reaction time of 0h to 6h. Compared with the traditional method, the synthetic method has the advantages of friendly environment, moderate reaction condition, stable catalyst heat, low cost, easy synthesis, high selectivity, repeated use and high activity maintenance and has strong industrial application prospect.
Patent•
06 Jul 2006
TL;DR: In this article, a method for producing carbonate crystals having aspect ratios of ≥ 25 and an average value of the major axis of ≤ 1 μm by reacting a metal ion source containing at least one kind of metal ion selected from Sr 2+, Ca 2+ ion, Ba 2+, ion, Zn 2+, and Pb 2− ion and a carbonic acid source in a liquid having a pH value of ≥ 90.
Abstract: PROBLEM TO BE SOLVED: To provide a method for producing carbonate crystals which have high aspect ratios and small sizes and can be dispersed in a monodispersed state SOLUTION: The method for producing the carbonate crystals is characterized by producing the carbonate crystals having aspect ratios of ≥25 and an average value of the major axis of ≤1 μm by reacting a metal ion source containing at least one kind of metal ion selected from Sr 2+ ion, Ca 2+ ion, Ba 2+ ion, Zn 2+ ion, and Pb 2+ ion and a carbonic acid source in a liquid having a pH value of ≥90 and including an aggregation preventing agent COPYRIGHT: (C)2006,JPO&NCIPI
Patent•
15 Jun 2006
TL;DR: In this article, the authors proposed a dust treatment method capable of efficiently reducing a concentration of heavy metal in a liquid after solid/liquid separation, which includes a step 12 for preparing a slurry by mixing the dust containing the heavy metal and water such that a ratio of dust and water becomes a ratio 1:2-1:20.
Abstract: PROBLEM TO BE SOLVED: To provide a dust treatment method capable of efficiently reducing a concentration of heavy metal in a liquid after solid/liquid separation. SOLUTION: The dust treatment method includes a step 12 for preparing a slurry by mixing the dust 10 containing the heavy metal and water 11 such that a ratio of dust and water becomes a ratio of 1:2-1:20; a first solid/liquid separation step 16 for solid/liquid-separating the prepared slurry to a first filtrate 13 and a residue 14; a step 18 for precipitating the heavy metal in the form of a hydroxide or a carbonate by adjusting pH of the first filtrate obtained by the first solid/liquid separation to 10-12 and adding a carbonic acid solution 17 to the first filtrate; a standing step 19 for further precipitating the left heavy metal by dissolving it in water by a co-precipitation effect with the carbonate by standing the first filtrate adjusted with pH and added with the carbonic acid solution; and a second solid/liquid separation step 23 for solid/liquid-separating the standing substance in the standing step to a second filtrate 21 and a residue 22. COPYRIGHT: (C)2006,JPO&NCIPI
Patent•
26 Jun 2006
TL;DR: In this paper, a using method of ester dialkyl carbonic acid as industrial solvent was described, which was characterized by the following: (1)degradable, friendly for environment; (2)compatible with other organic phase solvent; (3)micro-toxicity and fitful evaporating speed; (4)higher degreasing ability; (5)low cost; (6)wide usage.
Abstract: The invention discloses a using method of ester dialkyl carbonic acid as industrial solvent, which relates to the application of ester dialkyl carbonic acid and its composition, wherein the structural formula of ester dialkyl carbonic acid is as following; R1 is methyl, ethyl, propyl, butyl or its isomer; R2 is ethyl, propyl, butyl, amyl, hexyl, methoxylethyl, ethyoxylethyl, propoxyethyl, butoxyethyl, methoxypropyl, ethoxypropyl, propoxypropyl, butoxypropyl or its isomer; the sum of carbon atom of R1 and R2 is not more than 10.The invention is characterized by the following: (1)degradable, friendly for environment; (2)compatible with other organic phase solvent; (3)micro-toxicity and fitful evaporating speed; (4)higher degreasing ability; (5)low cost; (6)wide usage.
Patent•
26 Sep 2006
TL;DR: In this article, an alcohol-resistant transparent emulsified composition is obtained by emulsifying a composition comprising (a) edible oily material, (b) a mixture of refined decaglycerole oleate, (c) polyhydric alcohol, and (d) water.
Abstract: PROBLEM TO BE SOLVED: To provide an alcohol-resistant transparent emulsified composition excellent in alcohol resistance maintaining transparency even when added to an alcohol drink where essence with high alcohol content is used, and suppressed in foaming property even when the alcohol drink contains carbonic acid, and to provide a method for producing the same. SOLUTION: The alcohol-resistant transparent emulsified composition is obtained by emulsifying a composition comprising (a) edible oily material, (b) a mixture of refined decaglycerole oleate and decaglycerole stealate, (c) polyhydric alcohol, and (d) water. The method for producing the composition is provided. COPYRIGHT: (C)2008,JPO&INPIT
Patent•
25 Jan 2006
TL;DR: In this paper, a process for preparing high-uniformity and high-granularity magnetic hydro-talcite particles, which is composed of a magnetic core and a shell (carbonic acid radical-type hydrotalcite), is described.
Abstract: A process for preparing high-uniformity and high-granularity magnetic hydro-talcite particles, which is composed of a magnetic core and a shell (carbonic acid radical-type hydrotalcite), includes such steps as co-depositing to prepare magnetic nano-cores, mixing with relative salt solution, and growing the carbonic acid radical-type hydrotalcite on the surface of each nano-core by urea method. Its advantage is high magnetic target performance.
Patent•
17 Mar 2006
TL;DR: In this paper, the synthesis of cyclic carbonic acid ester is carried out by taking epoxide and carbon dioxide as raw materials without organic solvent, utilizing binary catalyst with transition metal salt and bidentate ionic liquid, cycloaddition reacting at 313.15-483.15K and 0.1-5.0Mpa, respectively.
Abstract: Synthesis of cyclic carbonic acid ester is carried out by taking epoxide and carbon dioxide as raw materials without organic solvent, utilizing binary catalyst with transition metal salt and bidentate ionic liquid, cycloaddition reacting at 313.15-483.15K and 0.1-5.0Mpa and synthesizing cyclic carbonic acid ester. It is simple and clean, has higher recovery rate and selectivity and can be re-used.
Patent•
06 Jul 2006
TL;DR: In this article, the molar ratio of aldehydes contained in an alcohol used in the regeneration process of an organotin alkoxide to a metal atom in a liquid to be regenerated was ≤ 0.1 in the production.
Abstract: PROBLEM TO BE SOLVED: To provide a method for continuously and repeatedly producing a carbonic acid ester in a high yield by using an organotin alkoxide and carbon dioxide. SOLUTION: The method for producing a carbonic acid ester comprises keeping the molar ratio of aldehydes contained in an alcohol used in the regeneration process of an organotin alkoxide to a metal atom in a liquid to be regenerated being ≤0.1 in the production. COPYRIGHT: (C)2006,JPO&NCIPI
Patent•
23 Mar 2006
TL;DR: Essential neutral textile additives (I) comprises reactive products of phosphorus pentoxide or polyphosphoric acid with one or more alcohols (alkyl phosphate) and carbonic acid and/or its derivative.
Abstract: Essential neutral textile additives (I) comprises reactive products of phosphorus pentoxide or polyphosphoric acid with one or more alcohols (alkyl phosphate) and carbonic acid and/or its derivative. An independent claim is also included for the preparation of (I).
Patent•
28 Jul 2006
TL;DR: In this article, a catalyst for coupling annular carbonates and organic dibasic acid ester to prepare alkyl carbonate and polyester was proposed, and the reaction temperature was 200-290Deg.
Abstract: The invention relates to a catalyst for coupling annular carbonates and organic dibasic acid ester to prepare alkyl carbonate and polyester, wherein said catalyst is metal acetate, alkali metal compound, organic tin compound and Al-Mg hydrotalcite; the mol ration between annular carbonates and organic dibasic acid ester is 1:0.2-5; the mass density of said catalyst is 0.01-10%; and the reaction temperature is 200-290Deg. C.
01 Jan 2006
TL;DR: In this article, it is shown from the distribution of calcite cements in sandstone reservoirs from Kela 2 gas field,Tarim basin, that the deposit of the calcite cement occurs in the sandstone reservoir with the groundwater of NaHCO_(3) patterns and the dissolution takes place in those with groundwater of CaCl_(2) patterns.
Abstract: The solubility of calcite in the diagenesis is closely related to the chemistry of groundwater and the temperature.The percentage of components of carbonic acid in groundwater is dependent on the pH value.Soluble CO_(2),HCO~-_(3) and CO~(2-)_(3) are the predominant components in the acidic medium with pH≤pK_(1),the neutral one with pK_(1)≤pH≤pK_(2) and the alkaline one with pH≥pK_(2),respectively.The total carbonic acid and the component concentrations in groundwater are controlled by the pH value,the partial pressure of gas CO_(2) and the solution-deposit effect of solid calcite.The pH value and the temperature of solution is the main factors to control the solubility of calcite.Based on the mass conservation condition,the initial [ΣCO_(2)]-[Ca~(2+)] value deeply influences the solubility of calcite in neutral and alkaline media.The condition with [ΣCO_2]_(0)[Ca~(2+)]_(0) in the solution is favorite to dissolution of calcite and that with [ΣCO_2]_(0)[Ca~(2+)]_(0) is favorite to deposit of calcite.It is shown from the distribution of calcite cements in sandstone reservoirs from Kela 2 gas field,Tarim basin,that the deposit of calcite cement occurs in the sandstone reservoirs with the groundwater of NaHCO_(3) patterns and the dissolution takes place in those with groundwater of CaCl_(2) patterns.It gives us an example to discuss the mechanism of dissolution and deposit of calcite cement controlled by groundwater patterns.
Patent•
16 Aug 2006
TL;DR: In this article, a cyclic carbonic acid ester from high-activity catalyst is carried out by utilizing efficient binary catalyst with transition metal salt and quaternary alkylphosphonium salt halide ionic liquid, cycloaddition reacting at 313.15-483.15K and 0.1-5.0Mpa.
Abstract: Production of cyclic carbonic acid ester from high-activity catalyst is carried out by utilizing efficient binary catalyst with transition metal salt and quaternary alkylphosphonium salt halide ionic liquid, cycloaddition reacting at 313.15-483.15K and 0.1-5.0Mpa and synthesizing cyclic carbonic acid ester. It is simple and clean, has recovery rate and selectivity and can be re-used.
Patent•
25 Jan 2006
TL;DR: In this article, a system for producing hypobromous acid is described, which includes a carbonic acid source in fluid communication with a chlorinator element for producing a chlorinated carbonic acids solution, and a bromine source for controlling the pH of the solution.
Abstract: A system for producing hypobromous acid is provided. An exemplary system includes a carbonic acid source in fluid communication with a chlorinator element for producing a chlorinated carbonic acid solution, a bromine source in fluid communication with the chlorinated carbonic acid solution, wherein the combination of carbonic acid with the bromine source produces hypobromous acid solution, and controlling the pH of the hypobromous acid solution.
Patent•
28 Dec 2006
TL;DR: In this article, an electric double layer capacitor has an electrode containing the alkaline-activation activated carbon of the graphite material and the organic electrolite in which a supporting electrolites is dissolved in a solvent containing chain carbonic acid ester or/and cyclic carbonic acids and aroma carboxilic acid esters, wherein the content of aroma CARB is made to be 50 or less weight% to all solvents.
Abstract: PROBLEM TO BE SOLVED: To provide an electric double layer capacitor excellent in initial performance and a performance maintenance ratio with high energy density, in which alkaline-activation activated carbon of a graphite material is used as a material for an electrode, and when chain carvonic acid ester or/and cyclic carbonic acid ester are used for an organic electrolite, the dissolution of the chain carvonic acid ester or/and cyclic carbonic acid ester is suppressed in a high ambient temperature. SOLUTION: The electric double layer capacitor has an electrode containing the alkaline-activation activated carbon of the graphite material and the organic electrolite in which a supporting electrolite is dissolved in a solvent containing chain carbonic acid ester or/and cyclic carbonic acid and aroma carboxilic acid ester, wherein the content of aroma carboxilic acid ester is made to be 50 or less weight% to all solvents. COPYRIGHT: (C)2007,JPO&INPIT