Abstract: Ammonium biacetate is a useful material for heat storage applications such as culinary implements, medicinal uses, and solar energy storage.

Abstract: A method for producing esters and carboxylic acids from lower alkyl alcohols, ethers, esters and ester-alcohol reactant mixtures and includes the step of contacting a vaporous mixture of the reactants, carbon monoxide and a halide with a supported catalyst under vapor-phase carbonylation conditions. The catalyst includes iridium and a second metal selected from group 5 (vanadium, niobium, tantalum) metals of the periodic table of elements. Desirably, the iridium and secondary metal are deposited on activated carbon as a support material. In a preferred aspect of the invention, the vapor phase carbonylation process is useful for preparing acetic acid, methyl acetate or a mixture thereof.

Abstract: The present invention relates to an improved process for producing an organic carboxylic acid having (n+1) carbon atoms by reacting an alcohol having n carbon atoms with carbon monoxide in the presence of a rhodium catalyst system. More particularly, the present invention relates to carbonylation of alcohol such as methanol catalyzed by a rhodium system to produce acetic acid. The characteristic of the present invention is the addition of a catalyst stabilizer in the reaction medium to avoid or to alleviate the precipitation of the catalyst in the liquid phase. The catalyst stabilizer as used herein is a pyridine derivative having substituent(s) of such as (CH2)mCOOR or (CH2)mSO3R (R═H or hydrocarbons; m=0-6).

Abstract: Disclosed is a method to manufacture high purity acetic acid. Although described in relation to that produced by a low water carbonylation process the present invention is applicable to other mechanisms for production of acetic acid which results in formation of permanganate reducing compounds such as acetaldehyde and its derivatives, and alkyl iodide impurities in intermediate process streams. It has been found that permanganate reducing compounds and alkyl iodides may be conveniently removed from a light phase of an intermediate stream in the reaction process by employing a multiple distillation process coupled with an optional post extraction of acetaldehyde. The distillation process involves first distilling a light phase to concentrate the permanganate reducing compounds, and in particular the acetaldehyde, and then separating the permanganate reducing compounds and alkyl iodides in a second distillation tower.

Abstract: A process for removing higher organic iodides, including hexyl iodide, from an acetic acid product obtained by carbonylating methanol and/or a reactive derivative thereof in the presence of a finite concentration of water, Group VIII noble metal catalyst, methyl iodide as co-catalyst, and optionally a catalyst promoter, which process includes the step of subjecting an aqueous composition comprising acetic acid and at least one higher organic iodide to distillation in a column, or section of a column, separating water overhead from a dry acetic acid fraction, wherein the water concentration on the feed tray of the column, or section of the column, is greater than 8% by weight and the water concentration in the head of the column, and/or section of the column, is greater than 70% by weight.

Abstract: The method of the present invention provides an improvement upon prior art methanol carbonylation methods which substantially reduces the production of carbonyl impurities. The production of carbonyl impurities, particularly acetaldehyde, crotonaldehyde, and 2-ethyl crotonaldehyde, in methanol carbonylation reactions has been found to decrease by maintaining less than about 4.5 wt % methyl iodide in the reaction medium during the course of the reaction.

Abstract: An oxide catalyst comprising the elements Mo, V, Nb and Pd. The novel catalytic system provides both higher selectivity and yield of acetic acid in the low temperature one step vapor phase direct oxidation of ethane with molecular oxygen containing gas without production of side products such as ethylene and CO. The feed gas is contacted with a catalyst containing Mo, V, Nb, Pd and O in the ratio a:b:c:d:x where a is 1 to 5; b is 0 to 0.5; c is 0.01 to 0.5; d is 0 0.2 and x is a number determined by the valence of the other elements in the catalyst.

Abstract: The method of the present invention provides an improvement upon prior art methanol carbonylation methods which substantially reduces the production of carbonyl impurities. The production of carbonyl impurities, particularly acetaldehyde, crotonaldehyde, and 2-ethyl crotonaldehyde, in methanol carbonylation reactions has been found to decrease by maintaining a partial pressure of hydrogen between about 0.1 and 4 psia at reaction total pressure of from about 15 to about 40 atmospheres total reaction pressure.

Abstract: A process for preparing acetic acid by gas-phase oxidation of saturated C4-hydrocarbons and their mixtures with unsaturated C4-hydrocarbons in a tube reactor using a coated catalyst comprising an inert nonporous support body and a catalytically active mixed oxide composition comprising (a) one or more oxides selected from the group consisting of titanium dioxide, zirconium dioxide, tin dioxide and aluminum oxide and (b) from 0.1% to 1.5% by weight, based on the weight of the component (a) and per m2/g of specific surface area of the component (a), of vanadium pentoxide applied to the outer surface of the support body, wherein a gas mixture comprising oxygen or oxygen-containing gas, one or more C4-hydrocarbons and water vapor and having a C4-hydrocarbon/air (oxygen) volume ratio of from 0.2/99.8 to 25/75 and a C4-hydrocarbon/water vapor volume ratio of from 1/1 to 1/60 is reacted over the coated catalyst at a temperature of from 100° C. to 400° C. and a gauge pressure of from 0.2 to 50 bar.

Abstract: The invention relates to a shell catalyst for producing acetic acid by gas-phase oxidation of unsaturated C4-hydrocarbons, comprising an inert non-porous carrier and a catalytically active mixed oxide material applied on the outer surface of the carrier, wherein said material contains (a) one or several oxides from the group titanium dioxide, zircon dioxide, stannic dioxide, aluminum oxide, and b) 0.1 to 1.5 wt. % vanadium pentoxide in relation to the weight of the constituent (a) and per m2/g of the specific surface of the constituent (a).

Abstract: A mixed metal oxide catalytic system comprising MoVNbPd or MoLaVPd providing higher selectivity and space time yield of acetic acid in the low temperature single stage oxidation of ethylene with molecular oxygen-containing gas and steam with very minimum or without the production of side products such as acetaldehyde, and methods of using the same.

Abstract: A process is disclosed for selectively preparing acetic acid from a gaseous feed of ethane, ethylene or mixtures thereof, as well as oxygen, at an increased temperature, on a catalyst which contains the elements W, X, Y and Z in the gram-atom ratio a:b:c:d, associated with oxygen. In the formula WaXbYcZd (I), X stands for one or several elements selected from the group Pd, Pt, Ag and/or Au; Y stands for one or several elements selected from the group V, Nb, Cr, Mn, Fe, Sn, Sb, Cu, Zn, U, Ni and/or Bi; Z stands for one or several elements selected from the group Li, Na, K, Rb, Cs, Be, Mg, Ca, Sr, Ba, Sc, Y, La, Ti, Zr, Hf, Ru, Os, Co, Rh, Ir, B, Al, Ga, In, Tl, Si, Ge, Pb, P, As and/or Te; a equals 1, b is a number higher than 0, c is a number higher than 0, and d is a number from 0 to 2. Also disclosed is said catalyst.

Abstract: A peracetic acid disinfectant is used to clean particulate inorganic materials such as calcium and magnesium from fibers and filters. The method allows polysulfone filtens in particulate to be reused after soaking for at least about 18 hours, and most preferably at least about 24 hours, in the peracetic acid based solution. The cleaned filters have been shown to have a reuse life of in excess of 30% and up to about 60-80% of the original life of the filter. The peracetic acid solution and method may be used to clean both hollow fiber and pleated polysulfone filters.

Abstract: There is described a process for the production of a substantially anhydrous salt of an organic acid which comprises reacting a basic compound of a metal with the appropriate organic acid, removing a substantial proportion of water present so as to produce the salt or its hydrate as a liquid phase and then dissolving the liquid phase in a non-aqueous solvent.

Abstract: A method of controlling the carbon monoxide flow to a reactor wherein acetic acid is produced continuously by feeding carbon monoxide through a control valve and methanol and/or a reactive derivative thereof, there being maintained in the reactor a liquid reaction composition comprising at least 5% w/w methyl acetate, a finite concentration of water, from 1 to 30% w/w methyl iodide, a Group VIII noble metal catalyst, optionally at least one promoter and acetic acid comprising the remainder of the composition which method comprises the steps of: (i) measuring the carbon monoxide flow through the control valve; (ii) performing a background calculation to arrive at a time-averaged carbon monoxide flow rate; (iii) adding a constant value to the time-averaged carbon monoxide flow to arrive at a maximum allowable carbon monoxide flow rate; and (iv) feeding information comprising the calculated maximum allowable carbon monoxide flow rate to a control system which operates in a manner such that the carbon monoxid

Abstract: An ethylbenzene production system comprises a reactor vessel, a vapor phase ethylene feed stream, a benzene feed stream entering the reactor vessel, and a product stream containing ethylbenzene exiting the reactor vessel. The reactor vessel has an ethylation section and a benzene stripping section, whereby fluid communication via integrated vapor and liquid traffic is maintained between the ethylation section and stripping section. The vapor phase ethylene feed stream contains 3 to 50 mol % ethylene and at least 20 mol % methane entering the reactor vessel.

Abstract: A process for the production and purification of acetic acid by carbonylation of methanol, DME or reactive derivatives thereof in a distillation column containing a homogenous catalyst system.

Abstract: A method for the vapor-phase carbonylation of lower alkyl alcohols to esters and optionally, carboxylic acids using a catalyst having a platinum on a solid support material as a first component and a vaporous halide as a second component. Desirably, the catalyst includes platinum on an activated carbon support and the vaporous halide is selected from hydrogen halides, alkyl halides and aryl halides having up to 12 carbon atoms, and mixtures thereof.

Abstract: A mixed metal oxide Mo--V--Ga--Pd--Nb--X (where X=La, Te, Ge, Zn, Si, In or W) catalytic system providing a higher selectivity to acrylic acid in the low temperature partial oxidation of propane with a molecular oxygen-containing gas.

Abstract: A mixed metal oxide catalytic system consisting of molybdenum, vanadium, lanthanum and palladium providing higher yields of acetic acid in low temperature single stage oxidation of ethane with molecular oxygen-containing gas without or with reduced production of by-products such as ethylene and CO.

Abstract: Methods for the catalytic production of vinyl acetate monomer from ethane, ethylene or an ethane/ethylene mixture using a first catalyst containing MoVNbPd, MoVLaPdNbX (where X is Al, Ga, Ge or Si) or MoVNbX (where X is P, B, Hf, Te, As or mixtures thereof) in the first step of oxidation and using a conventional VAM catalyst for the second step. The method produces high yields to acetic acid and vinyl acetate without the coproduction of carbon monoxide.

Abstract: A vapor phase process for the carbonylation of lower alkyl alcohols to esters and optionally, carboxylic acids using a catalyst containing iridium and at least one second metal selected from the Lanthanide Series. Desirably, the iridium and secondary metal are deposited on activated carbon as a support material. In a preferred aspect of the invention, the vapor phase process is useful for preparing acetic acid, methyl acetate or a mixture thereof by contacting the catalyst with a vapor comprising methanol, a halide and carbon monoxide under carbonylation process conditions.

Abstract: The present invention relates to a thermotolerant bacterium, designated as Acetobacter sp. I14-2, with high production of acetic acid which was isolated from spoiled banana in Taiwan. The present invention also relates to compositions containing the new species and methods for acetic acid production.

Abstract: A process for the production of a carbonyl compound such as acetic acid by reacting a carbonylatable compound such as methanol with a carbon monoxide in the presence of a carbonylation catalyst containing a noble metal complex supported on a porous, cross-linked vinylpyridine resin at a temperature of 140-250.degree. C., a carbon monoxide partial pressure of 7-30 kg/cm.sup.2 and a hydrogen partial pressure of 0.1-5 kg/cm.sup.2 to obtain a liquid product containing the carbonyl compound and an unreacted CO-containing gas product. The water content and the carbonylation degree of the liquid product within the reactor are maintained at 0.5-10% by weight and 0.5-0.9, respectively, The carbonyl compound is separated from the liquid product in a flasher and/or a distillation tower formed of titanium or a titanium-palladium alloy. The liquid product is introduced into a pressure reducing valve and then mixed with the CO-containing gas product before being fed to the flasher and/or distillation tower.

Abstract: Disclosed is a method for producing a predetermined cesium compound. The method comprises treating a cesium-containing material with a suitable reagent to dissolve at least a portion of the cesium contained in the material and form a slurry; adding a base comprising slaked lime or calcium carbonate and an acid containing the anion of the predetermined cesium compound to the slurry comprising the dissolved cesium; and separating the predetermined cesium compound.

Abstract: Provided is a process for producing acetic acid by carrying out reaction of methyl formate in the presence of a Group VIII metal catalyst, at least one iodine compound, acetic acid and carbon monoxide, continuously drawing a reaction mixture from a reactor, introducing the reaction mixture into a flash distillation zone, separating an evaporated component and an unevaporated component, recycling the unevaporated component to the reaction zone, and obtaining acetic acid from the evaporated component, wherein formic acid and methyl formate are allowed to coexist in the flash distillation zone and/or the recycling zone. According to this process, no loss of methyl formate and formic acid is caused and only methyl formate is used as a starting material with basically requiring no supply of carbon monoxide.

Abstract: Wood preservative systems comprising (a) a biocidal effective amount of (i) at least one di C.sub.8 -C.sub.12 alkyl quaternary ammonium carboxylate having the formula ##STR1## wherein R.sup.1 and R.sup.2 are a C.sub.8 -C.sub.12 alkyl group; R.sup.3 is a substituted or unsubstituted, interrupted or uninterrupted C.sub.1 -C.sub.100 group; l and q independently are 1, 2 or 3 and (l) (q) is 1, 2, or 3; and n is 0 or an integer from 1 to 50; (ii) at least one di C.sub.8 -C.sub.12 alkyl quaternary ammonium borate having the formula ##STR2## wherein R.sup.1 and R.sup.2 are defined as above, and a is 2 or 3, but when a is 2, b is 0 or 1, and when a is 3, b is 0, 1, or 2; or (iii) a combination of (i) and (ii); and (b) a solvent are provided. These carboxylate quats as well as carboxylate quats wherein R.sup.1 is a C.sub.1 -C.sub.20 alkyl or aryl-substituted alkyl group and R.sup.2 is a C.sub.8 -C.sub.20 alkyl group are preferably prepared by an indirect or a direct synthesis.

Abstract: A liquid-phase process for hydrolyzing a carboxylic acid alkyl ester having 2 to 18 carbon atoms to provide a product mixture comprising a carboxylic acid and an alcohol comprising contacting a feedstock comprising the carboxylic acid alkyl ester and water with an acidic carbon catalyst under reaction conditions sufficient to form the product mixture comprising the carboxylic acid and the alcohol. Suitable acidic carbon catalysts include charcoal and carbons produced from a variety of sources including coconut shells, coal, wood and peat. Carbon catalysts may be rendered acidic by treatment with nitric acid.

Abstract: In the process for the production of acetic acid by carbonylation of methanol and/or a reactive derivative thereof the water concentration in the liquid reaction composition is maintained at a steady-state concentration by at least one process step selected from the group consisting of (i) recovery and disposing of water from at least part of the overhead process stream from the light ends column and (ii) replacing at least a portion of the methanol feed with a component selected from the group consisting of methyl acetate, dimethyl ether, acetic anhydride and mixtures thereof. The recovered aqueous effluent from this and other processes may be purified of carboxylic acid by reactive distillation with at least one C.sub.1 to C.sub.3 alcohol.

Abstract: An object of the present invention is to provide an operating method which can reduce the amount of silver or mercury dissolved in a solution after contact and can increase the usage of silver or mercury without installing new treating facilities in a process for removing iodine compounds contained in an organic medium, particularly acetic acid or a mixture of acetic acid or acetic anhydride, by contacting them with a cation exchange resin in which at least 1% of the active sites are converted to a silver form or a mercury form.The operating method described above is characterized by carrying out the operation while elevating the temperatures in stages while contacting the organic medium, particularly acetic acid or a mixture of acetic acid and acetic anhydride, containing the iodine compounds with a cation exchange resin.

Abstract: The present invention provides a compound of the formula ##STR1## which inhibit squalene synthetase and cholesterol biosynthesis and are useful in the treatment of e.g., hyperlipidaemia, atherosclerosis, or fungal infections, processes for the preparation of the compounds of the invention, intermediates useful in these processes, and pharmaceutical compositions containing the compounds.

Abstract: A process for the production of acetic acid which comprises reacting carbon monoxide with a carbonylatable reactant comprising greater than 10%, typically from 30 to 100%, by weight dimethyl ether introduced to a reactor in which there is maintained at elevated temperature a liquid reaction composition comprising a Group VIII noble metal catalyst, for example rhodium or iridium, methyl iodide promoter, an optional co-promoter and water at a concentration in the liquid reaction composition of from 1.0 to 10% by weight.

Abstract: Methods for treating cystic fibrosis are described. The methods involve the administration of a protein enhancing agent, differentiating agent and/or carboxy-compound to a subject afflicted with cystic fibrosis such that mutant cystic fibrosis transmembrane regulator protein present within cystic fibrosis-associated cells becomes functional. Other aspects described include therapeutic compositions and packaged drugs.

Abstract: A process for purifying acetic acid which comprises: introducing a feedstock aqueous solution of acetic acid having an acetic acid concentration of from 10 to 50% by weight into an extractor; supplying an extracting medium containing isopropyl acetate in an amount from 0.6 to 3.

Abstract: In a process for purifying a carboxylic acid fraction obtained by liquid phase carbonylation of an alkyl alcohol and/or its reactive derivative in which volatile iridium- and/or volatile co-promoter contaminants are converted to involatile forms by contacting with an iodide in the absence of carbon monoxide or at a partial pressure less than that of the carbonylation reaction. The involatile contaminants are then separated from the carboxylic acid.

Abstract: Formic acid is difficult to separate from acetic acid by conventional distillation or rectification because of the proximity of their boiling points. Formic acid can be readily separated from acetic acid by using azeotropic distillation. Effective agents are acetonitrile and isopropyl acetate.

Abstract: This invention relates to the preparation of cesium salts from cesium-aluminum-alum in a process in which the cesium-aluminum-alum is reacted in a single vessel in the presence of water with calcium hydroxide in an amount which is equimolar to the amount of aluminum and with a readily water-soluble calcium salt in an amount which is equimolar to the amount of cesium and the precipitated aluminum hydroxide and the precipitated calcium sulfate are separated by filtration or centrifugation.

Abstract: In the production step, alcohol is reacted with carbon monoxide in a reaction solvent in the presence of a rhodium-containing solid catalyst obtained by immobilizing rhodium in an insoluble carrier (I) containing a pyridine ring in its resin structure and an alkyl iodide containing an alkyl group of 1 to 5 carbon atoms, to produce a reaction product having a water content of 0.5 to 10% by weight; and in the subsequent removing step, an organic carboxylic acid is separated and recovered from the reaction product, and the recovered organic carboxylic acid is contacted with an insoluble carrier (II) containing a pyridine ring in its resin structure, to remove an iodide contained in the organic carboxylic acid.

Abstract: A process for the production of a carboxylic acid by carbonylation of an alkyl alcohol or its reactive derivative comprises contacting the reactant with carbon monoxide in a liquid reaction composition comprising: (a) an iridium catalyst or rhodium catalyst, (b) alkyl halide, (c) at least a finite concentration of water and (d) rhenium as promoter.

Abstract: A process for the preparation of cycloalkanols by the hydrolysis of cycloalkyl C.sub.1 -C.sub.4 fatty acid esters, which comprises the following steps:a) reaction of cycloalkyl C.sub.1 -C.sub.4 fatty acid esters with water at a temperature of from 30.degree. to 250.degree. in the liquid phase yielding a reaction mixture consisting of cycloalkyl C.sub.1 -C.sub.4 fatty acid esters, cycloalkanol, C.sub.1 -C.sub.4 fatty acids, and water.b) separation of the reaction mixture obtained in stage a) at a temperature of from 0.degree. to 200.degree. C. into a top phase consisting substantially of cycloalkanol and cycloalkyl C.sub.1 -C.sub.4 fatty acid esters and a bottom phase consisting substantially of water and C.sub.1 -C.sub.4 fatty acids.c) separation of cycloalkanol from the top phase obtained in stage b) by distillation and recycling unconverted cycloalkyl C.sub.1 -C.sub.4 fatty acid esters to stage a).

Abstract: A process is provided for making bulk calcium magnesium acetate in a substantially pure crystalline form. The crystalline CMA contains less than about 0.5% of water soluble impurities.

Abstract: Process for improving a controlled oxidation reaction between at least one reactant and oxygen, in which at least one reactant is reacted with oxygen or an oxygen containing gas, constituting a reaction mixture, in the presence of at least one additional gas which is introduced into said reaction mixture and is selected from methane, ethane and helium, and the resulting reaction product from the oxidation reaction is possibly treated so as to give a final product.

Abstract: In a process for the production of acetic acid by carbonylation of methanol in the presence of a rhodium carbonylation catalyst, methyl iodide and an iodide salt stabiliser the improvement resides in maintaining a finite concentration of water of up to about 10% by weight and a methyl acetate concentration of at least 2% by weight in the liquid reaction composition and recovering the acetic acid product by passing the liquid reaction composition through a flash zone to produce a vapour fraction which is passed to a single distillation column from which an acetic acid product is removed.

Abstract: The present invention relates to(1) a Ru-Sn hetero-polynuclear complex as a novel catalyst which has a high catalytic activity and is useful for producing acetic acid and/or methyl acetate from methanol, and(2) a process for producing acetic acid and/or methyl acetate through a one-stage reaction starting with methanol wherein a catalyst can be used at a high concentration and the catalytic activity is maintained throughout the reaction.

Abstract: The alkaline earth metal potassium acetate according to the invention comprises14 to 19 % by weight of calcium (Ca.sup.++),0 to 1% by weight of magnesium (Mg.sup.++),11 to 16 % by weight of potassium (K.sup.+),62 to 71% by weight of acetate (CH.sub.3 COO.sup.-),0 to 7 % by weight of waterand0 to 2 % by weight of water-insoluble componentsFor its preparation, a calcium oxide containing at least 85% of CaO, acetic acid and potassium hydroxide solution are reacted with one another and the reaction product is granulated to give particles of 0.5 to 5 mm. The alkaline earth metal potassium acetate according to the invention can be used as an environment-friendly deicing agent causing little corrosion.

Abstract: The alkaline earth metal sodium acetate according to the invention comprises18 to 22% by weight of calcium (Ca.sup.++),0 to 1% by weight of magnesium (Mg.sup.++),4 to 7% by weight of sodium (Na.sup.+),66 to 75% by weight of acetate (CH.sub.3 COO.sup.-),0 to 7% by weight of water and0 to 2% by weight of water-insoluble componentsFor its preparation, a calcium oxide containing at least 85% of CaO, acetic acid and sodium hydroxide solution are reacted with one another and the reaction product is granulated to give particles of 0.5 to 5 mm. The alkaline earth metal sodium acetate according to the invention can be used as an environment-friendly deicing agent causing little corrosion.

Abstract: This invention relates to a composition for and method of storing and using acetic acid or propionic acid, the composition comprising an alkali(ne earth) metal salt of acetic acid or propionic acid and an aliphatic carboxylic acid which has a pKa value lower than that of acetic acid or propionic acid respectively. When this composition is brought into contact with a solvent system capable of allowing ionisation of the salt and the aliphatic carboxylic acid, free acetic acid or propionic acid is released in situ. This method enables the free acids to be stored and released at the point of use thereby substantially reducing the risks of corrosion and unpleasant odors.

Abstract: Improved deicer compositions containing crystalline double salts formed from mixtures of relatively low molecular weight carboxylic acids (for example, mixtures of formic acid and acetic acid) are provided. The deicer compositions are generally prepared by neutralizing an aqueous mixture containing at least two carboxylic acids or salts thereof, adjusting the pH to between about 7 and about 10, and drying the aqueous mixture to obtain a double salt crystalline product. Double salts containing sodium cations and double salts containing sodium cations and at least one cation selected from the group consisting of potassium, calcium, and magnesium provide effective deicing compositions which are environmentally safer than conventional deicing compositions.

Abstract: A methanol carbonylation catalyst includes a rhodium complex supported on a porous, cross-linked vinylpyridine resin, wherein the vinylpyridine resin has a cross-linking degree of 30-60%, a pore volume of 0.1-0.4 ml/g and an average pore diameter of 20-100 nm. The catalyst may be prepared by contacting the pyridine ring-containing resin with an aqueous solution containing rhodium ion and then contacting the resulting rhodium ion-carrying resin with carbon monoxide and an alkyl iodide in an organic solvent to convert the rhodium ion to a rhodium complex bound to the resin. Acetic acid is produced by reacting carbon monoxide with methanol at a temperature of 140.degree.-250.degree. C. and a partial pressure of carbon monoxide of 7-30 kg/cm.sup.2 in the presence of an alkyl iodide and the above catalyst.

Abstract: The present invention relates to a process for inexpensively and effectively recovering a high-purity organic acid, according to which a crude organic acid is subjected to extraction treatment with an organic solvent to obtain an organic solvent extract containing an organic acid; the organic solvent extract is mixed with a high-pressure gas to precipitate and separate impurities thereby obtaining a solution containing a high-purity organic acid; and the organic acid is separated from the solution to obtain a high-purity organic acid.