Abstract: A process for producing (meth)acrylic acid, comprising a crystallizing step of supplying a cooling medium from a refrigerator to a crystallizer and returning the cooling medium from the crystallizer to the refrigerator, thereby obtaining a (meth)acrylic acid crystal from a (meth)acrylic acid-containing solution; and a melting step of supplying a heating medium from a refrigerator to the crystallizer and returning the heating medium from the crystallizer to the refrigerator, thereby melting the (meth)acrylic acid crystal; wherein the crystallizing step and the melting step are respectively performed at least once, thereby producing purified (meth)acrylic acid from a crude (meth)acrylic acid solution; temperature of the cooling medium discharged from the refrigerator is maintained constant at temperature T1; temperature of the cooling medium to be returned to the refrigerator is maintained constant at temperature T2; the temperature T2 is adjusted depending on a production amount of the purified (meth)acrylic a

Abstract: The invention relates to a continuous neutralization process in which at least one ethylenically unsaturated carboxylic acid is neutralized at least partly with a base and the temperature of the neutralized solution is less than 70° C., and also to an apparatus for carrying out the process.

Abstract: The present invention provides a method for reducing fouling of equipment during separation and purification steps of (meth)acrylic acid production by early removal of aldehyde impurities by adding a hydrazide compound well upstream of the separation and purification steps. In particular, carbodhydrazide may be added as an aldehyde scavenging agent to aqueous (meth)acrylic acid prior to dehydration and purification steps.

Abstract: Processes for the purification of bio-based acrylic acid to crude and glacial acrylic acid are provided. The bio-based acrylic acid is produced from hydroxypropionic acid, hydroxypropionic acid derivatives, or mixtures thereof. The purification includes some or all of the following processes: extraction, drying, distillation, and melt crystallization. The produced glacial or crude acrylic acid contains hydroxypropionic, hydroxypropionic acid derivatives, or mixtures thereof as an impurity.

Abstract: A thermal separation process between a gas ascending in a separating column and a liquid descending in the separating column, which comprise (meth)acrylic monomers, wherein the separating column comprises a sequence of crossflow mass transfer trays, the crossflow mass transfer trays of which have passage orifices for the ascending gas in crossflow direction both in front of and beyond a downcomer for the descending liquid, and such crossflow mass transfer trays and one such crossflow mass transfer tray in a sequence of crossflow mass transfer trays present in a separating column.

Abstract: Processes for the purification of bio-based acrylic acid to crude and glacial acrylic acid are provided. The bio-based acrylic acid is produced from hydroxypropionic acid, hydroxypropionic acid derivatives, or mixtures thereof. The purification includes some or all of the following processes: extraction, drying, distillation, and melt crystallization. The produced glacial or crude acrylic acid contains hydroxypropionic, hydroxypropionic acid derivatives, or mixtures thereof as an impurity.

Abstract: In one embodiment, the invention is to process for producing acrylics. The process includes the steps of contacting a crude product stream with an extraction agent mixture and diluting the crude product stream with at least one diluent.

Abstract: The process for the distillation of a gas mixture comprising (meth)acrylic acid obtained from the gas-phase oxidation of at least one (meth)acrylic acid precursors is improved through the use of coupled distillation columns. In a first column, the gaseous mixture is dehydrated while in a second column, the dehydrated gaseous mixture is distilled into product, overhead and bottoms streams.

Abstract: The objective of the present invention is to provide a process for producing highly pure (meth) acrylic acid stably and efficiently with crystallization. The process for production of (meth)acrylic acid according to the present invention is characterized in comprising the steps of cooling a crude (meth)acrylic acid solution in a crystallization apparatus until the temperature of a cooling medium discharged from the crystallization apparatus is stabilized in the range of higher than the solidification point of the crude (meth)acrylic acid solution in the crystallization apparatus and not more than the solidification point plus 5° C.; then bringing the crude (meth)acrylic acid solution in the crystallization apparatus to a supercooled condition by setting the temperature of a cooling medium supplied to the crystallization apparatus at the temperature of not more than the solidification point of the crude (meth)acrylic acid solution minus 1° C.

Abstract: A process for inhibiting polymerization of (meth)acrylic acid and/or (meth)acrylic esters by introducing an oxygenous gas into the (meth)acrylic acid and/or the (meth)acrylic ester, in which the (meth)acrylic acid and/or the (meth)acrylic ester has a degree of purity of at least 95% and is in the liquid state.

Abstract: In one aspect, a process for the preparation of a superabsorbent polymer is described herein. In some embodiments, the process comprises (I) preparing acrylic acid, wherein the process comprises (a1) provision of a fluid F1 having a composition comprising from about 5 to about 20 wt. % of hydroxypropionic acid, salts thereof, or mixtures thereof; from about 0.1 to about 5 wt. % of inorganic salts; from about 0.1 to about 30 wt. % of organic compounds which differ from hydroxypropionic acid; from 0 to about 50 wt. % of solids; and from about 20 to about 90 wt. % of water; (a2) dehydration of said hydroxypropionic acid to give a fluid F2 containing acrylic acid; and (a3) purification of said fluid F2 to give a purified acrylic acid phase comprising acrylic acid having a purity of at least 70 wt. %; and (II) polymerizing the acrylic acid of (I) to form a superabsorbent polymer.

Abstract: In one embodiment, the invention is to process for producing acrylics. The process includes the steps of contacting a crude product stream with an extraction agent mixture. The weight ratio of the extraction agent mixture to the crude product stream is greater than 0.25:1.

Abstract: A process for starting up a separating process for purifying removal of acrylic acid crystals from a suspension S of crystals thereof in mother liquor with a hydraulic wash column which has a crystal melt circuit including crystal melt space, and a process space and a distributor space which are separated by an end with passages connecting the two spaces, in which the crystal bed is formed for the first time by first filling the crystal melt circuit and, at least partly, the process space with an acrylic acid-comprising startup liquid whose acrylic acid crystal formation temperature is less than or equal to the temperature of the suspension S increased by 15° C.

Abstract: The present invention relates to a process for preparing acrylic acid by two-stage heterogeneously catalyzed partial gas phase oxidation of propylene, in which the propylene source used is a preceding propane dehydrogenation and in which the first oxidation stage is operated with restricted propylene conversion, and unconverted propane and propylene present in the product gas mixture of the second partial oxidation stage are recycled substantially into the preceding propane dehydrogenation.

Abstract: [Problem] There is provided, in a process for producing acrylic acid having a catalytic gas-phase oxidation reaction step, a condensation step, a collection step, a distillation step, a crystallization step, an acrylic acid recovering step or the like, a production method for acrylic acid, in which contamination of acrylic acid with protoanemonin without providing any additional purification treatment to the resultant purified acrylic acid can be reduced.

Abstract: The present invention relates to a process for preparation of pure methacrylic acid, at least comprising the process steps: a) gas phase oxidation of a C4 compound to obtain a methacrylic acid-comprising gas phase, b) condensation of the methacrylic acid-comprising gas phase to obtain an aqueous methacrylic acid solution, c) separation of at least a part of the methacrylic acid from the aqueous methacrylic acid solution to obtain at least one crude methacrylic acid-comprising product; d) separation of at least a part of the methacrylic acid from the at least one crude methacrylic acid-comprising product by means of a thermal separation process to obtain a pure methacrylic acid.

Abstract: In one embodiment, the invention is to 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 process further comprises the step of recovering high purity acrylate product using precipitation. The alkylenating agent stream comprises at least 1 wt % alkylenating agent and the intermediate product stream comprises acrylate product.

Abstract: In one embodiment, the invention is to a process for producing an acrylate product. The process comprises the step of providing a crude product stream comprising the acrylate product, an alkylenating agent, and water. The process further comprises the step of contacting at least a portion of the crude product stream or a derivative thereof with an extraction agent mixture to form an extract stream and a raffinate stream. The extract stream comprises acrylate product and extraction agent. The raffinate stream comprises alkylenating agent and water. Preferably, the extraction agent mixture comprises at least two extraction agents.

Abstract: In one embodiment, the invention is to a process for producing an acrylate product. The process comprises the step of providing a crude product stream comprising the acrylate product, an alkylenating agent, light ends, and non-condensable gases. The process further comprises the step of separating the crude product stream to form a cooled vapor stream and at least one condensed crude product stream without the addition of heat. The process further comprise the step of separating at least a portion of the condensed crude product stream to form an alkylenating agent stream comprising at least 1 wt. % alkylenating agent and the intermediate product stream comprises acrylate product.

Abstract: In one embodiment, the invention is to 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.

Abstract: The present invention relates to a process for purifying methacrylic acid, wherein the reaction mixture obtained by a reaction of methacrylamide with water is cooled by mixing with an aqueous medium and then passed into a phase separator. The present invention further describes a system for performing the process according to the invention.

Abstract: The present invention relates to a method for purifying an unpurified phase, containing a target product, preferably (meth)acrylic acid, water, and at least one impurity differing from the target product and from water comprising: a) crystallizing the target product and water; b) separating the crystals from the mother liquor created in step a); c) melting at least part of the separated crystals to form a melt; and d) recycling at least part of said melt to step b). The invention further relates to a method for the production of a purified phase, containing a target product and water, a method for the production of a polymer based on (meth)acrylic acid, polymers that may be obtained by means of said method, chemical products, such as fibers or molded bodies, and the use of polymers.

Abstract: Process for distillatively purifying polymerizable compounds using a high-boiling, inert, thermally long-term-stable substance as a boiling oil, characterized in that the boiling oil is disposed in the bottom of a rectification column.

Abstract: Disclosed is an apparatus for recovering an acrylic acid from a mixture containing acrylic acid, acrylic acid dimer and impurities with high boiling point, including: an acrylic acid recovering device that comprises an acrylic acid distillation unit being present within an acrylic acid dimer pyrolysis tank, and is operated under reduced pressure; a separation column for removing impurities with high boiling point from the mixture which is introduced into the acrylic acid recovering device; and a line for introducing the mixture into the acrylic acid recovering device.

Abstract: A process for separating acrylic acid present as a main product and glyoxal present as a by-product in a product gas mixture of a partial gas phase oxidation of a C3 precursor compound, in which a liquid phase P is obtained, which consists of acrylic acid to an extent of at least 70% of its weight and, based on the molar amount of acrylic acid present therein, comprises at least 200 molar ppm of glyoxal, in which the glyoxal is separated from the acrylic acid in the liquid phase P by crystallization.

Abstract: In one aspect, a process for the preparation of a superabsorbent polymer is described herein. In some embodiments, the process comprises (I) preparing acrylic acid, wherein the process comprises (a1) provision of a fluid F1 having a composition comprising from about 5 to about 20 wt. % of hydroxypropionic acid, salts thereof, or mixtures thereof; from about 0.1 to about 5 wt. % of inorganic salts; from about 0.1 to about 30 wt. % of organic compounds which differ from hydroxypropionic acid; from 0 to about 50 wt. % of solids; and from about 20 to about 90 wt. % of water; (a2) dehydration of said hydroxypropionic acid to give a fluid F2 containing acrylic acid; and (a3) purification of said fluid F2 to give a purified acrylic acid phase comprising acrylic acid having a purity of at least 70 wt. %; and (II) polymerizing the acrylic acid of (I) to form a superabsorbent polymer.

Abstract: The present invention provides a method for effectively preventing the precipitation related to manganese acetate in the pipe for sending a polymerization inhibitor and the like, and the polymerization of (meth)acrylic acid. A first method of the present invention for producing (meth)acrylic acid, characterized in comprising steps of: producing a (meth)acrylic acid-containing gas by catalytic vapor phase oxidation reaction; and obtaining a (meth)acrylic acid-containing fluid by providing the (meth)acrylic acid-containing gas into a condensation column or an absorption column; wherein manganese acetate is used as a polymerization inhibitor; manganese acetate is dissolved into a (meth)acrylic acid aqueous solution containing not more than 10% by mass of (meth)acrylic acid, and the like, to obtain a manganese acetate aqueous solution; and the manganese acetate aqueous solution is provided into the condensation column or the absorption column.

Abstract: A system and process for separating methacrolein (MA) from methacrylic acid (MAA) and acetic acid in the gas phase product from partial oxidation of isobutylene (IB) in two oxidation steps is disclosed. The process and system maximize recovery of all three components at minimum capital and energy cost, under conditions that minimize polymerization conditions and plugging by solids deposition in compressors, columns, etc.

Abstract: The process for the distillation of a gas mixture comprising (meth)acrylic acid obtained from the gas-phase oxidation of at least one (meth)acrylic acid precursors is improved through the use of coupled distillation columns. In a first column, the gaseous mixture is dehydrated while in a second column, the dehydrated gaseous mixture is distilled into product, overhead and bottoms streams.

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 process for the distillation of a gas mixture comprising (meth)acrylic acid obtained from the gas-phase oxidation of at least one (meth)acrylic acid precursors is improved through the use of coupled distillation columns. In a first column, the gaseous mixture is dehydrated while in a second column, the dehydrated gaseous mixture is distilled into product, overhead and bottoms streams.

Abstract: A process for producing ethanol including a combination of biochemical and synthetic conversions results in high yield ethanol production with concurrent production of high value coproducts. An acetic acid intermediate is produced from carbohydrates, such as corn, using enzymatic milling and fermentation steps, followed by conversion of the acetic acid into ethanol using esterification and hydrogenation reactions. Coproducts can include corn oil, and high protein animal feed containing the biomass produced in the fermentation.

Abstract: A process for heterogeneously catalyzed partial gas phase oxidation of propylene to acrylic acid, in which the starting reaction gas mixture comprises cyclopropane as an impurity and the acrylic acid, after conversion from the product gas mixture into the condensed phase, is removed with the aid of a crystallative removal.

Abstract: A process for purifying removal of a chemical target compound from a suspension of crystals thereof in mother liquor in a wash column with forced transport of the crystal bed from the top downward, in which crystals are removed from the lower end of the crystal bed with a rotating removal device and melted, and a portion of the crystal melt is conducted back toward the crystal bed as wash melt, the removal device being secured with a drive shaft conducted into the wash column from the bottom through an inlet having a seal, said drive shaft being driven about its longitudinal axis by a drive unit for rotation and being mounted so as to be rotatable about its longitudinal axis in more than one bearing, such that the mounting in one of the bearings absorbs the downward force acting on the drive shaft, the mounting in two or more bearings absorbs forces acting radially outward from the drive shaft, and the mounting in one bearing is additionally capable of absorbing an upward force acting on the drive shaft.

Abstract: The invention relates to a process for the preparation of acrylic acid and a process for the preparation of polyacrylic acid comprising the process steps: (a1) preparation of 3-hydroxypropionic acid from a biological material to give a fluid, in particular aqueous, phase containing 3-hydroxypropionic acid; (a2) dehydration of the 3-hydroxypropionic acid to give a fluid, in particular aqueous, solution containing acrylic acid; (a3) purification of the solution containing acrylic acid by a suspension crystallization or a layer crystallization to give a purified phase; and corresponding devices for carrying out these processes, and acrylic acid and polyacrylates. The invention is distinguished in that acrylic acid and polyacrylates can thereby be prepared efficiently, inexpensively, and sustainably with simple means and with a high purity on the basis of regenerable raw materials.

Abstract: The present invention provides a method for extractive recovery and conversion of selected compounds, such as methacrylic acid (MAA) and 2-methacrylamide (MAM), from a stream derived from purification of methyl methacrylate (MMA) or methacrylic acid (MAA) produced via a conventional ACH route process.

Abstract: A process for production of (meth)acrylic acid is disclosed. The process includes synthesizing and distillatively working-up a crude (meth)acrylic acid phase to obtain a (meth)acrylic acid phase and a dimer phase including (meth)acrylic acid dimers and/or (meth)acrylic acid oligomers. At least a part of the (meth)acrylic acid dimers and/or of the (meth)acrylic acid oligomers from the dimer phase is split to obtain a (meth)acrylic acid including a low-boiling phase and a high-boiling phase including less (meth)acrylic acid than the low-boiling phase. At least a part of the (meth)acrylic acid from the low-boiling phase is separated by forming of one or more crystals to obtain a pure (meth)acrylic acid and a residue. Also disclosed is a device for production of (meth)acrylic acid, a process for production of a polymer as well as chemical products based on or including (meth)acrylic acid or a polymer as well as the use of (meth)acrylic acid or polymers in chemical products.

Abstract: The objective of the present invention is to provide a crystallization device and a crystallization process for obtaining (meth)acrylic acid with higher purity without causing leakage of a crude solution by preventing complete clogging in a crystallization tube from occurring.

Abstract: Accumulation of polymer on equipment, which is in contact with polymerizable material during normal process operation, is minimized by the method and apparatus of the present invention. The method involves positioning and affixing the equipment, such as a pressure relief device, to process apparatus, such as a distillation column, proximate to a wetted region comprising liquid phase fluid in the process apparatus, such that the moving liquid phase fluid is at least intermittently in contact with the equipment and one or more of accumulated polymerizable material, condensate comprising same, and polymer, is washed off of the equipment.

Abstract: A process for producing (meth)acrylic acid, comprising the step of repeating a crystallization operation “n” times (providing “n” is an integer 2 or more) to produce purified (meth)acrylic acid from crude (meth)acrylic acid, wherein a (meth)acrylic acid solution is crystallized and the crystallized (meth)acrylic acid is melted to obtain a (meth)acrylic acid melt in the crystallization operation; wherein a constant amount Ak of the (meth)acrylic acid solution is subjected to the kth crystallization operation (providing “k” is an integer 1 or more and n?1 or less), and the (meth)acrylic acid melt obtained by the kth crystallization operation is utilized as the (meth)acrylic acid solution for the k+1th crystallization operation without being discharged from a crystallizer or is transferred from the crystallizer to a k+1th storage tank for storing the (meth)acrylic acid solution to be used in the k+1th crystallization operation depending on the stored amount of the k+1 th storage tank.

Abstract: The objective of the present invention is to provide a process for production of (meth)acrylic acid with improved production efficiency by efficiently shifting from heating procedure to cooling procedure for a crystallizer. A process for production of (meth)acrylic acid according to the present invention is characterized in comprising the steps of crystallizing (meth)acrylic acid from a crude (meth)acrylic acid solution by using a batch type crystallizer, and melting the obtained (meth)acrylic acid crystal to obtain a (meth)acrylic acid melted liquid; wherein preliminary cooling of the crystallizer for the next crystallization step is started during transferring the (meth)acrylic acid melted liquid from the crystallizer.

Abstract: A process for replacing the stabilization of (meth)acrylic monomers, wherein phenothiazine is removed from phenothiazine-containing (meth)acrylic monomers by adsorption on activated carbon, and then a moderately active polymerization inhibitor is optionally added.

Abstract: A method is disclosed for the recovery of an organic acid from a dilute salt solution in which the cation of the salt forms an insoluble carbonate salt. An amine and CO2 are introduced to the solution to form the insoluble carbonate salt and a complex between the acid and the amine. The acid/amine complex is thermally dissociated, or “cracked”, in the presence of a water immiscible solvent in which the amine is selectively soluble and in which the acid is not appreciably soluble. The organic acid may then be recovered from the water by any suitable means such as distillation, reactive distillation, extraction, or reactive extraction.

Abstract: The objective of the present invention is to provide a process for producing highly pure (meth) acrylic acid stably and efficiently with crystallization. The process for production of (meth)acrylic acid according to the present invention is characterized in comprising the steps of cooling a crude (meth)acrylic acid solution in a crystallization apparatus until the temperature of a cooling medium discharged from the crystallization apparatus is stabilized in the range of higher than the solidification point of the crude (meth)acrylic acid solution in the crystallization apparatus and not more than the solidification point plus 5° C.; then bringing the crude (meth)acrylic acid solution in the crystallization apparatus to a supercooled condition by setting the temperature of a cooling medium supplied to the crystallization apparatus at the temperature of not more than the solidification point of the crude (meth)acrylic acid solution minus 1° C.

Abstract: A process for operating a continuous removal of a target product X in the form of fine crystals of a liquid phase P comprising the target product X and constituents other than the target product X by cooling suspension crystallization in the secondary chamber of an indirect heat exchanger to which liquid phase P flows continuously with simultaneous continuous flow through the primary chamber of the indirect heat exchanger with a coolant, and continuous withdrawal of a crystal suspension S having a degree of crystallization Y from the secondary chamber in two operating states I and II, wherein the coolant temperature is lower, the mass flow of liquid phase P is greater and the molar proportion of the constituents other than the target product X in the liquid phase P in operating state II is greater than in operating state I.

Abstract: A process for producing (meth)acrylic acid of the present invention comprises the steps in the following order: a crystallization step of supplying a cooling medium cooled by a heat source device to a crystallizer to obtain a (meth)acrylic acid crystal from a crude (meth)acrylic acid solution; an adjustment step of returning the cooling medium discharged from the crystallizer to the crystallizer without cooling; a sweating step of supplying a heating medium to the crystallizer to partially melt the (meth)acrylic acid crystal, thereby obtaining a melted liquid, and discharging the melted liquid from the crystallizer; and a melting step of supplying the heating medium to the crystallizer to melt the (meth)acrylic acid crystal, thereby obtaining purified (meth)acrylic acid. According to the present invention, purified (meth)acrylic acid with high purity can be obtained.

Abstract: The present invention relates to recovery of aqueous (meth)acrylic acid by condensation of a (meth)acrylic acid-containing stream to produce aqueous (meth)acylic acid having a higher concentration of (meth)acrylic acid and a lower concentration of formaldehyde, i.e., not more than 0.1 weight %, than the aqueous (meth)acrylic acid produced using hithertofore known separation methods. The (meth)acrylic acid-containing stream may be the raw product stream of catalytic oxidation at least one C2-C4 alkane or alkene.

Abstract: The present invention relates to reducing corrosion of distillation equipment during azeotropic distillation of (meth)acrylic acid in the presence of dissolved copper, by providing aqueous (meth)acrylic acid having not more than 0.1% by weight formaldehyde, based on the total weight of the aqueous (meth)acrylic acid. The source of the copper may, for example, be copper-based polymerization inhibitors added to the aqueous (meth)acrylic acid and/or distillation equipment.

Abstract: Improvement in separating lower carboxylic acids from aqueous streams via liquid-liquid extraction with pressurized liquefied propylene and/or propane, wherein carboxylic acid is transferred from the aqueous phase into the liquid solvent phase (extract).

Abstract: A process for continuously removing a target product X in the form of fine crystals from a liquid phase P comprising the target product X and constituents other than the target product X by cooling suspension crystallization in the secondary chamber, into which the liquid phase P flows continuously, of an indirect heat exchanger with simultaneous continuous flow of a coolant through the primary chamber of the indirect heat exchanger and continuous withdrawal of a crystal suspension S having a degree of crystallization Y from the secondary chamber, in which the degree of crystallization Y is adjusted on the basis of a heat balance conducted continuously with the aid of a process computer.