Abstract: Provided herein are compositions and processes concerning efficient downstream processing of products derived from organic acids pretreatment of plant materials.

Abstract: A method for manufacturing carboxylic acid that includes the following steps is provided. First, subjecting an aqueous mixture, including carboxylic acid and at least 5 wt. % dissolved magnesium chloride, to a forward extraction step using a first organic liquid, including an organic solvent, the organic solvent being selected from the group of C5+ ketones, thereby obtaining an organic carboxylic acid solution and an aqueous waste liquid including magnesium chloride. Second, subjecting the organic carboxylic acid solution to a back extraction step wherein the carboxylic acid is extracted from the organic carboxylic acid solution into an aqueous liquid, thereby obtaining an aqueous carboxylic acid solution and a second organic liquid. Third, subjecting the aqueous waste liquid including magnesium chloride derived from the forward extraction to a thermal decomposition step at a temperature of at least 300° C., thereby decomposing the magnesium chloride to magnesium oxide and HCl.

Abstract: Provided herein are methods and systems for converting natural gas, and specifically methane, into higher-value oxycarbon products, such as methanol, methyl formate, and formic acid. The natural gas is introduced into an aqueous solution with hydroxyl radicals and reacted in ambient conditions to form the desired products in the presence of a metal catalyst. The methods described herein overcome the “over-activation” dilemma of prior art methods that lead to the formation of undesirable carbon oxide compounds. Methods and apparatus for forming hydrogen peroxide via electrolysis and for forming hydroxyl radicals from the hydrogen peroxide via reaction with ferrous ions are also provided.

Abstract: The invention relates to a process to separate formic acid from methyltetrahydrofuran (MTHF) said process comprising subjecting a composition comprising formic acid and MTHF to distillation, characterized in that the process comprises adding water to said distillation. This allows for cost-efficient recovery and recycling of MTHF, for example in process to produce and recover formic acid from a biomass hydrolysate.

Abstract: The invention relates to a process for dehydrating aqueous 3-hydroxypropionic acid to acrylic acid in the liquid phase, wherein aqueous acrylic acid is removed continuously from the liquid phase and the aqueous 3-hydroxypropionic acid and/or the liquid phase have a high content of oligomeric 3-hydroxypropionic acid.

Abstract: A process comprising subjecting a composition comprising an alpha- or beta-hydroxycarboxylic acid, water, an extraction solvent, and an acid catalyst to extractive dehydration to form an unsaturated carboxylic acid product.

Abstract: The azeotrope, or near azeotrope, of methanol and MMA is separated via extractive distillation using an extractive distillation solvent comprising cyclohexanone.

Abstract: This invention relates to a process for the purification of acrylic acid from a mixture containing acrylic acid and acetic acid, comprising the following steps: extraction of the mixture containing acrylic acid and acetic acid with an extractant stream, whereby a raffinate stream and an extract stream are obtained, distillation of the extract stream, whereby an acrylic acid stream and a return stream are obtained, wherein the return stream contains acetic acid and is recirculated into the extraction. Furthermore, the invention may include a plant for carrying out this process.

Abstract: The present invention describes a process for preparing alpha-beta-unsaturated carboxylic acids by dehydration of hydroxycarboxylic or alkoxycarboxylic acids which are substituted in the alpha position, in particular 2-hydroxyisobutyric acid, while avoiding accumulation of by-products and additives.

Abstract: Mixture of succinic esters, which is characterized in that the alkyl radical has a proportion of alkyl components having less than 9 carbon atoms of not more than 15% by mass, the alkyl radical has a proportion of alkyl components having more than 9 carbon atoms of not more than 25% by mass and the proportion of 3,5,5-trimethylhexyl radicals is not more than 5 mol % and the proportion of linear n-nonyl radicals is not more than 15 mol %.

Abstract: A process for producing an acrylate product. The process comprises the step of providing a crude product stream comprising the acrylate product and an alkylenating agent. The process further comprises the step of separating at least a portion of the crude product stream to form an alkylenating agent stream and an intermediate product stream. The alkylenating agent stream comprises at least 1 wt % alkylenating agent and the intermediate product stream comprises acrylate product. The separating is performed in at least one column at an operating pressure ranging from 40 kPa to 80 kPa.

Abstract: Disclosed is a process for the separation of water from a liquid phase medium containing an aliphatic carboxylic acid using azeotropic distillation in the presence of an entrainer. The entrainer, water, and organics are subsequently separated, wherein the entrainer is recycled back to the azeotropic distillation column and organics recycled back to the oxidation reactor.

Abstract: The present invention relates in general terms to a process for preparing alkyl methacrylates, comprising as steps: providing an acetone cyanohydrin by a process according to one of the preceding claims; contacting the acetone cyanohydrin with an inorganic acid to obtain a methacrylamide; contacting the methacrylamide with an alcohol in the presence of an inorganic acid in a reactor to obtain an alkyl methacrylate; continuously discharging at least a portion of the alkyl methacrylate from the reactor into a distillation column as a vapor stream; the discharge being effected by feeding a discharge stream comprising steam into the reactor, to an apparatus for preparing alkyl methacrylates, to a process for preparing polymers based at least partly on alkyl methacrylates, to the use of the alkyl methacrylates obtainable by the process according to the invention in chemical products, and to chemical products based on alkyl methacrylates obtainable by the process according to the invention.

Abstract: The present invention provides a (meth)acrylic acid collecting method for collecting a (meth)acrylic acid from a mixed gas that includes an organic byproduct, a steam, and a (meth)acrylic acid that are generated in a production reaction of the (meth)acrylic acid, which includes the steps of a) contacting the mixed gas that includes the organic byproduct, the steam, and the (meth)acrylic acid with a (meth)acrylic acid absorption solvent to obtain a gas that includes the organic byproduct and the steam and the (meth)acrylic acid containing solution while the gas and the (meth)acrylic acid containing solution are separated from each other; b) contacting the gas that includes the organic byproduct and the steam that are obtained in the step a with the organic byproduct absorption solvent to obtain the gas that includes the steam and the organic byproduct containing solution while the gas and the organic byproduct containing solution are separated from each other; c) supplying the gas that includes the steam that

Abstract: The invention relates to a method and a device for the purification of an aqueous solution of an organic acid having a boiling point at atmospheric pressure of less than 450° C., which further has approximately 275 g carboxylate ions/l or less, preferably 250 g carboxylate ions/l or less, and preferably less than 1% by weight ionic impurities, calculated on the basis of the total solution. In particular, the invention relates to a method and a device for the continuous purification and concentration, on an industrial scale, of an aqueous solution of an organic acid having a boiling point at atmospheric pressure of less than 450° C. According to the method, this solution is subjected to two or more distillation steps, the first distillation step being carried out at a temperature of from 80° to 150° C. and a pressure of from 50 to 250 mbar, and the second distillation step being carried out at a temperature of from 80° to 200° C. and a pressure of from 0.01 to 50 mbar.

Abstract: Processes for removing water from organic solvents, such as ethanol. The processes include distillation in two columns operated at sequentially higher pressure, followed by treatment of the overhead vapor by one or two membrane separation steps.

Abstract: Processes for removing water from organic solvents, such as ethanol. The processes include distillation in two columns operated at sequentially higher pressure, followed by treatment of the overhead vapor by one or two membrane separation steps.

Abstract: In a method for recovering acid from an aqueous etching mixture containing HF, HNO3, H2SiF6 and HNO2 which has been used for purifying polycrystalline silicon, the used etching mixture is distilled progressively so that approximately from 20 to 50 wt. % of the mixture is distilled off as dilute acid containing more than 90 wt. % of the silicon dissolved as hexafluorosilicic acid in a first fraction, and the water contained in the used etching mixture having been reduced by approximately 10-30 wt. %, this water-depleted mixture is then concentrated by evaporation to a residue of about 1 to 5 wt. % of the initial amount of used etching mixture during which a second fraction is distilled off, and the residue is disposed of.

Abstract: A process is disclosed that relates to the removal of impurities, specifically benzoic acid, from a mother liquor produced in the synthesis of carboxylic acid, typically terephthalic acid.

Abstract: The invention relates to a process for separating close-boiling, homo- and heteroazeotropic mixtures by using ionic liquids. Due to the selectivity and unusual combination of properties of the ionic liquids the process is superior to conventional extractive rectification from the point of view of costs and energy.

Abstract: The invention relates to a method and a device for the purification of an aqueous solution of an organic acid having a boiling point at atmospheric pressure of less than 450° C., which further has approximately 275 g carboxylate ions/1 or less, preferably 250 g carboxylate ions/1 or less, and preferably less than 1% by weight ionic impurities, calculated on the basis of the total solution. In particular, the invention relates to a method and a device for the continuous purification and concentration, on an industrial scale, of an aqueous solution of an organic acid having a boiling point at atmospheric pressure of less than 450° C. According to the method, this solution is subjected to two or more distillation steps, the first distillation step being carried out at a temperature of from 80° to 150° C. and a pressure of from 50 to 250 mbar, and the second distillation step being carried out at a temperature of from 80° to 200° C. and a pressure of from 0.01 to 50 mbar.

Abstract: The invention relates to an apparatus and a process for the preparation of anhydrous or substantially anhydrous formic acid. This apparatus is constructed partly or entirely of substantially zirconium-free materials. The extractant employed is a liquid of the general formula I where the radicals R1 and R2 are alkyl, cycloalkyl, aryl or aralkyl groups, or R1 and R2 jointly, together with the N atom, form a heterocyclic 5- or 6-membered ring, and only one of the radicals is an aryl group, and where R3 is hydrogen or a C1–C4-alkyl group. The apparatus has a synthesis reactor (6), a hydrolysis reactor (1), three distillation devices (2,4,5) and an extraction device (3).

Abstract: The invention relates to a method for separating and purifying an aqueous mixture that mainly consists of acetic acid, formic acid and high-boiling substances by extraction with a solvent in a cyclic process. The inventive method is characterized in that the flow of raffinate is fed to a solvent stripping column (11) with the major part of the water in order to remove the water from the cycle. The flow of extract is fed to a solvent recovery distillation column (8). In a first step, a mixture (A) that consists of water and solvent, is separated by overhead distillation. A mixture (B) that consists of acetic acid, formic acid and high-boiling substances is separated via a sump. Once the formic acid is removed in a column (29), mixture (B) is separated in an acetic acid distillation column to give pure acetic acid and high-boiling substances.

Abstract: A method for the separation and purification of an aqueous mixture of main components, namely acetic acid and formic acid and non-volatiles by extraction, uses a solvent in a circulatory system. A raffinate stream is mixed with the larger proportion of water from a solvent stripper column (11) for the removal of water. The extraction stream is introduced into a solvent distillation column (8), from which in a first step involving the use of a mixture (A) containing a larger proportion of the solvent is separated out via a header and a mixture (B) of formic acid, water and solvent is separated out via a side offtake and a mixture (C) of acetic acid and non-volatiles is also separated out. A mixture (B) is introduced into a formic acid distillation column (4) for further processing, and a mixture (C) is introduced into an acetic acid distillation column (5), and purified acetic acid is subsequently isolated in the acetic acid distillation column (5) from the header.

Abstract: A method of recovering acrylic acid from a mixture comprising acrylic acid, water and acetic acid is disclosed, which includes:

Abstract: The present invention concerns a method for producing acrylic acid which involves subjecting an acrylic acid-containing aqueous solution obtained by catalytic vapor phase oxidation of propylene and/or acrolein to evaporation whereby an acrylic acid-containing vapor is obtained; and subjecting the acrylic acid-containing vapor to azeotropic dehydration. The present invention offers a number of advantages including a reduce amount of polymer that may adhere to the surface of an azeotropic dehydration column, a low-blowing separation column or an in a high-boiling separation column in a plant for producing acrylic acid. Consequently, the production plant can be operated for a long time without stopping operations.

Abstract: An improved process for preparing an aromatic dicarboxylic acid wherein the improvement resides in dehydrating and recovering solvent from a feed stream having from 20% to 40% by weight water via azeotropic distillation with organic phase reflux using an entrainer selected from isobutyl acetate, n-propyl acetate or an entrainer with a boiling point between isobutyl acetate and n-propyl acetate.

Abstract: A process as been found for the removal of water from reaction mixtures of acids or acid anhydrides or of aqueous alkali metal hydroxide solutions with alcohols using vapor permeation/pervaporation at the boiling point of the reaction mixture, which includes initially introducing the lowest-boiling educt in less than the stoichiometric amount, based on the other particular educt, together with this other educt, heating the reaction mixture to the boiling point and freeing the vapor mixture, which is formed from the boiling reaction mixture and includes chiefly water and the lowest-boiling component, from water on a membrane, recycling the vapor mixture which has been freed from water into the reaction mixture and topping up the reaction mixture with the lowest-boiling educt in the course of the reaction.

Abstract: A is a process for removing water from an alkanesulfonic acid such as methanesulfonic acid or ethanesulfonic acid by mixing an azeotropic excess of a phenolic compound with water and the alkanesulfonic acid, then boiling off substantially all of the water, and leaving as a remnant substantially all the alkanesulfonic acid and some of the phenol. This process is particularly useful for recycling an alkanesulfonic acid for a reaction which requires the phenolic compound as one of the reagents. One such reaction is the alkanesulfonic acid catalyzed condensation reaction of a phenolic compound with an .alpha.haloketone to form a chlorinated intermediate of a dihydroxy-.alpha.-alkylstilbene such as 4,4'-dihydroxy-.alpha.-alkylstilbene (DHAMS).

Abstract: A method for recovering carboxylic acids from a dilute aqueous solution thereof having a concentration below about ten percent (10%) by weight, which includes passing the dilute acid solution through a reverse osmosis separator, thereby producing a permeate substantially free of acid and a retentate having an acid concentration above about ten percent (10%) by weight. The retentate is contacted with a liquid extractant for acids to produce an acid-rich extractate and an acid-free raffinate. The acid is then recovered from the acid-rich extractate.

Abstract: Vinyl formate containing formic acid, acetaldehyde and water following synthesis is separated from formic acid and water in a first distillation stage and from acetaldehyde in a second stage to give pure vinyl formate.

Abstract: A method for recovering carboxylic acids from a dilute aqueous solution thereof having a concentration below about ten percent (10%) by weight, which includes passing the dilute acid solution through a reverse osmosis separator, thereby producing a permeate substantially free of acid and a retentate having an acid concentration above about ten percent (10%) by weight. The retentate is contacted with a liquid extractant for acids to produce an acid-rich extractate and an acid-free raffinate. The acid is then recovered from the acid-rich extractate.

Abstract: Disclosed is a method for recovering carboxylic acids having from one to ten carbon atoms, and particularly formic acid, acetic acid and mixtures of formic and acetic acids, from aqueous solutions, in which the aqueous solution is contacted with solvent consisting essentially of mixed trialkylphosphine oxides in counter-current liquid-liquid extraction flow in a contacting step to thereby transfer the acids from the aqueous solution to the solvent, thus producing a raffinate relatively low in acid content and a rich solvent. The rich solvent is preferably dehydrated to separate water therefrom and yield a dehydrated rich solvent. The dehydrated rich solvent then has the acids stripped from it and the resulting lean solvent is then returned to the liquid-liquid extraction step, while the separated acids are split into their constituent components in a distillation operation.

Abstract: The present invention relates to a process for the preparation of tetrafluorophthalic acid and/or tetrafluorophthalic anhydride by reacting a compound of the formula ##STR1## in which X is a radical ##STR2## which is optionally mono- or polysubstituted on the aromatic nucleus by fluorine and/or chlorine and/or alkyl groups having 1 to 4 carbon atoms, or is a radical ##STR3## in which R.sub.1, R.sub.2 and R.sub.3 are as defined, with water, and subsequently removing the water still present by azeotropic distillation or extracting the tetrafluorophthalic acid and/or its anhydride with a water-insoluble solvent or solvent mixture.

Abstract: Fluorinated carboxylic acids which do not have the required purity for use as emulsifier in the polymerization of fluorinated monomers can, if necessary after prior de-watering, be treated with oxidants, whereupon the isolation of the pure product is carried out by crystallisation or, preferably, by distillation.

Abstract: A process for purification of adipic acid during crystallization by modifying the crystal morphology to decrease incorporation of impurities through the introduction of an effective amount of an additive to the crystallizing solution.

Abstract: Anhydrous or substantially anhydrous formic acid is prepared by hydrolyzing methyl formate in the presence of a formamide and then obtaining the formic acid from the hydrolysis mixture by distillation, by a method in which the hydrolysis is carried out in the presence of 0.5-3 moles, per mole of methyl formate, of a water-soluble formamide of the general formula I ##STR1## where R.sup.1 and R.sup.2 are each alkyl or together form an alkylene group, giving a 5-membered to 7-membered ring, with the proviso that the sum of the carbon atoms in R.sup.1 and R.sup.2 is 5 or 6 and, in the case of an alkylene group, a carbon atom which is not directly bonded to the N atom can be replaced by an oxygen atom.

Abstract: Formic acid cannot be completely removed from formic acid--water mixtures by distillation because of the presence of the maximum azeotrope. Formic acid can be readily removed from mixtures containing it and water by using extractive distillation in which the extractive distillation agent is cyclohexanone, isophorone or a mixture of these with certain organic compounds. Typical examples of effective agents are cyclohexanone; isophorone; cyclohexanone and neodecanoic acid; isophorone and diisobutyl ketone.

Abstract: Acrylic acid cannot be completely separated from water by conventional distillation or rectification because of the minimum boiling azeotrope. Acrylic acid can be readily separated from water by extractive distillation. Effective agents are dimethylsulfoxide, sulfolane, dimethylformamide or dimethylacetamide.

Abstract: Carboxylic acids are recovered from wet organic solutions by reducing the solutions' water content thus causing the acids to precipitate as recoverable crystals.

Abstract: A preparation membrane for pervaporation which comprises a crosslinked reaction mixture of a polyvinyl alcohol or polyvinyl alcohol copolymer and a polystyrene sulfonic acid or polystyrene sulfonic acid copolymer. A method for separating a mixture of water and an organic compound by using the membrane is also disclosed.

Abstract: Formic acid cannot be completely removed from formic acid and water mixtures by distillation because of the presence of the maximum azeotrope. Formic acid can be readily removed from formic acid - water mixtures by extractive distillation in which the extractive agent is a mono carboxylic acid mixed with certain high boiling organic compounds. Examples of effective agents are: hexanoic acid and butyl benzoate; octanoic acid and nitrobenzene; heptanoic acid, benzyl benzoate and pelargonic acid.

Abstract: An improved method for dehydration and concentration of an aqueous solution containing an organic compound is disclosed. The solution is evaporated to produce a gaseous mixture comprising an organic compound vapor and a water vapor. The water vapor is selectively removed from the gaseous mixture by permeation through an aromatic polyimide gas separation membrane while the gaseous mixture being kept in contact with a surface on one side of the gas separation membrane at a temperature of 70.degree. C. or higher to obtain a gaseous mixture comprising the organic compound vapor and a reduced amount of a water vapor.

Abstract: A process for the removal of water from a lower alkanesulfonic acid-water mixture by causing the mixture to run down the internal walls of two vertical evaporator columns operated in series, is disclosed herein.

Abstract: Formic acid cannot be completely removed from formic acid and water mixtures by distillation because of the presence of the maximum azeotrope. Formic acid can be readily removed from formic acid - water mixtures by extractive distillation in which the extractive agent is a benzoic acid derivative mixed with certain higher boiling organic compounds. Examples of effective agents are: o-toluic acid and heptanoic acid; 2-benzoylbenzoic acid and methyl salicylate; p-hydroxybenzoic acid, pelargonic acid and 2-hydroxyacetophenone.

Abstract: A process for removing volatile acids from aqueous solutions which involves steam stripping a volatile acid from an aqueous solution and contacting the vaporized acid with a reactable cation to form a salt of the acid. A preferred embodiment of apparatus comprises an elongated distillation column having therein a plurality of zones or stages wherein the volatile acid in the aqueous feed stream is vaporized by steam and then the vaporized acid is carried by the steam into a salt formation zone or stage to react with a reactable cation to form a salt of the acid.

Abstract: Formic acid cannot be completely removed from formic acid and water mixtures by distillation because of the presence of the maximum azeotrope. Formic acid can be readily removed from formic acid--water mixtures by extractive distillation in which extractive agent is a dicarboxylic acid mixed with certain high boiling organic compounds. Examples of effective agents are: itaconic acid and diethylene glycol diethyl ether; azelaic acid, heptanoic acid and 2-hydroxyacetophenone.

Abstract: The amount of water required to effect efficient separation of a mixture of sulfuric acid and carboxylic acids by distillation, is reduced, by diluting the mixture while in the distillation column in a prescribed manner with sufficient water to provide a water:sulfuric acid mole ratio of about 1:1. The heat generated by the internal dilution reduces the energy requirement of the column. Feeding the dilution water to the column below the feed mixture is a key element of the process.

Abstract: Formic acid cannot be completely removed from formic acid and water mixtures by distillation because of the presence of the maximum azeotrope. Formic acid can be readily removed from formic acid - water mixtures by extractive distillation in which the extractive agent is ethylene carbonate or propylene carbonate, either alone or mixed with certain high boiling organic compounds. Examples of effective agents are ethylene carbonate and heptanoic acid; propylene carbonate, benzoic acid and isophorone; propylene carbonate, heptanoic acid and 2-hydroxyacetophenone.

Abstract: Impure formic acid cannot be completely removed from formic acid-water-impurity mixtures by distillation because of the presence of the maximum azeotrope between formic acid and water. Formic acid can be readily removed from mixtures containing it, water and impurities of the ether, ester, ketone or diketone type by using extractive distillation in which the extractive agent is a higher boiling oxygenated, nitrogenous or sulfur containing organic compound or a mixture of these. Examples of effective agents are adiponitrile; sulfolane and salicyclic acid; dimethylformamide, N,N-dimethylacetamide and ethylene glycol ethyl ether acetate.