Abstract: It is an object of the present invention to provide a process for producing easily polymerizable substance, which can realize stable operation of a purification system, and can stably maintain a production amount by avoiding production stoppage, upon production of an easily polymerizable substance in plural reactors. The present invention is directed to a process for producing easily polymerizable substance, which comprises mixing easily polymerizable substances obtained in plural reactors in advance, and supplying the mixture to a purification apparatus.

Abstract: A process for rectificatively separating liquids containing (meth)acrylic monomers in a rectification column is provided, in which a stream is withdrawn from the rectification column and recycled into the rectification column as a molecular oxygen-enriched liquid phase.

Abstract: Basic (meth)acrylates IV are prepared by transesterification of alkyl (meth)acrylates I in the presence of a catalyst and working-up of the reaction mixture by distillation, by a process in which a gas or gas mixture which is inert under the reaction conditions is passed through the reaction zone and/or heat exchanger.

Abstract: An low concentration dope is fed through a nozzle into a concentrating apparatus, and flash evaporation of the low concentration dope is performed at an end of the nozzle. The low concentration dope is concentrated thereby to an concentrating dope which is contained and heated in the concentrating apparatus. Thus part of solvents of the low concentration dope and the concentrating dope is evaporated to a solvent gas. The solvent gas is cooled and condensed in a condensing section of the concentrating apparatus, and thereafter drawn through a first exit from the concentrating apparatus. The concentrating dope is concentrated to a high concentration dope, which is drawn through a second exit from the concentrating apparatus.

Abstract: A method for purifying a crude (meth)acrylic acid obtained by a vapor phase catalytic oxidation method, characterized in that the crude (meth)acrylic acid having most parts of water and acetic acid removed therefrom, is fed to and distilled in a first distillation column of a purification system comprising first to third three distillation columns, the top fraction from the first distillation column is fed to and distilled in the second distillation column, the resulting top fraction is recovered as a high purity (meth)acrylic acid product, the bottoms from the first and second distillation columns are fed to and distilled in the third distillation column, and the resulting top fraction is fed to the first distillation column.

Abstract: This invention is providing a method for efficient treatment of the waste material from a process for production of acrylic acid and an acrylic ester. This is a method for the disposal of waste material, which at least one waste material selected from the group consisting of waste oil, waste water, and waste gas emitted from a process for production of acrylic acid is/are purified with at least one waste material selected from the group consisting of waste oil, waste water, and waste gas emitted from a process for production of an acrylic ester jointly. The efficiency of the treatment is enhanced by simultaneously treating the waste material.

Abstract: A process for producing a (meth)acrylic acid compound, which comprises distilling acrylic acid, methacrylic acid (these will hereinafter generally be referred to as “(meth)acrylic acid”) or an ester thereof (these will hereinafter generally be referred to as “a (meth)acrylic acid compound”) in a distillation column to obtain a purified (meth)acrylic acid compound, characterized in that in the course of operation of the distillation column including suspension and resumption of the operation, the distillation column is washed with water and, thereafter, inside washing with an organic solvent and/or azeotropic distillation in the presence of the organic solvent is conducted. In some cases, washing with alkaline water may be added prior to the washing with water. Washing of the distillation column for separating and purifying a crude (meth)acrylic acid compound, can be carried out easily.

Abstract: A process for preparing and/or working up mixtures by (meth)acrylic acid and/or (meth)acrylic ester in the presence of at least one polymerization inhibitor and at least one oxygenous gas, which comprises metering in at least part of the oxygenous gas at an exit rate of at least 50 mm/s.

Abstract: There is provided a method for storing (meth)acrylic acid or (meth)acrylic esters in a storage tank for receiving or discharging the (meth)acrylic acid or (meth)acrylic esters, which is capable of storing the (meth)acrylic acid or (meth)acrylic esters for a long period of time. According to the method of the present invention, upon storing the (meth)acrylic acid or (meth)acrylic esters in the storage tank for receiving or discharging the (meth)acrylic acid or (meth)acrylic esters, a concentration of suspended particulate matters contained in a gas phase portion of the storage tank is controlled to not more than 0.01 mg/m3.

Abstract: A process for inhibiting polymerization in the preparation of (meth)acrylic esters of C1–C8-alcohols, wherein the pH of the water of reaction supplied to the C1–C8-alcohol recovery is greater than 7.

Abstract: An apparatus and a process for purification of an acrylic acid family.

Abstract: A tert-C4–C8-alkyl (meth)acrylate is prepared by reacting (meth)acrylic acid with an olefin of the formula where R1 and R2, which may be identical or different, are methyl or ethyl and R3 is H, methyl or ethyl, in homogeneous phase in the presence of an acidic catalyst and isolating the tert-C4–C8-alkyl (meth)acrylate from the reaction mixture, by a process in which the catalyst is separated off as residue by a two-stage distillation of the reaction mixture and the tert-C4–C8-alkyl (meth)acrylate is isolated from the distillates. The novel process makes it possible to use acetic acid-containing (meth)acrylic acid. The danger of cleavage of the ester and of polymerization of (meth)acrylic compounds is reduced.

Abstract: There is provided a method for handling high-viscosity substances discharged from a production process of acrylic acid or esters thereof by gas-phase catalytic oxidation, which method is improved such that upon transporting the high-viscosity substances in a molten state to a storage tank through a pipeline, the retention or clogging of the high-viscosity substances in the pipeline can be effectively prevented without adding a solvent thereto, resulting in smooth transportation thereof through the pipeline.

Abstract: The present invention relates to a process for producing substituted glycerol acrylates from substituted epoxides. More specifically, the present invention relates to a process comprising the steps of (a) reacting a first reaction mixture comprising substituted epoxide with at least one epoxide opening catalyst and at least one acrylic acid to form a first reaction product comprising between about 60 and about 85 mole % substituted glycerol acrylate and said substituted epoxide; (b) treating said first reaction mixture with a nucleophilic compound to form a second reaction product which is substantially free of said substituted epoxide and which comprises said substituted glycerol acrylate and a nucleophile derivative of said substituted epoxide; and (c) treating said second reaction product to remove said nucleophile derivative and produce substituted glycerol acrylate having less than about 5 weight % difunctional impurities.

Abstract: Provided are a packed column arranged so as to be capable of effectively preventing polymerization of a polymerizable compound such as a (meth)acrylic acid in treating the compound, and a method for treating a polymerizable compound using the packed column. The packed column, which is provided with a packing support plate and is filled with a packing on the packing support plate, is arranged so as to include a packing layer (B) having a greater percentage of voids than that of a packing layer (A), between the packing support plate and the packing layer (A).

Abstract: A process for inhibiting a polymerization of an easily polymerizable compound purification system is disclosed. According to the present invention, the polymerization of the easily polymerizable compound such as (meth)acrylic acid and (meth)acrylate flowed into a vacuum section can be inhibited by contacting a liquid containing a polymerization inhibitor with the compound directly in the vacuum section. When the vacuum section includes a gas and liquid contact chamber (usually a condenser), the liquid containing a polymerization inhibitor may be supplied to the chamber. When the vacuum section includes a liquid ejector and/or a nash pump as a vacuuming device, the liquid containing a polymerization inhibitor may be circulated by the liquid ejector and/or the nash pump for reducing a pressure of a purifying section. Examples of easily polymerizable compounds are (meth)acrylic acid and (meth)acrylates.

Abstract: A process for the preparation of water-soluble polymers of esters of ethylenically unsaturated carboxylic acids and polyalkylene glycols by azeotropic esterification, in the presence of organic solvents which form an azeotrope with water, of ethylenically unsaturated carboxylic acids with polyalkylene oxides which are capped at one end by end groups, to a degree of at least 85 wt %, followed by free-radical polymerization of the resulting esters optionally together with other ethylenically unsaturated monomers, in aqueous medium, wherein the organic solvents are removed by azeotropic distillation from the reaction mixture during polymerization and the water that is removed by distillation is recycled or the quantity of water removed by distillation from the reaction mixture is replaced by a feed of fresh water.

Abstract: Water-soluble polymers of esters made from acrylic acid and alkylpolyalkylene glycols, obtainable by azeotropic esterification of a mixture of acrylic acid and alkylpolyalkylene glycol in a molar ratio of from 2 to 3:1 in the presence of at least 85% by weight, based on the alkylpolyalkylene glycol, of an organic solvent which forms an azeotrope with water, followed by free-radical polymerization, in an aqueous medium, of the mixture obtained during the esterification, where the organic solvent is distilled off azeotropically from the reaction mixture during the polymerization, and the water removed by distillation is returned to the mixture or replaced by a feed of fresh water, and preparation and use of these polymers as an additive to cementitious systems.

Abstract: The invention relates to a process for the preparation of esters of (meth)acrylic acid by (trans)esterifying (meth)acrylic acid or its ester derivatives with monohydric or polyhydric alcohols in the presence of an acidic (trans)esterification catalyst, wherein said process after the formation of the esters of (meth)acrylic acid further comprises reacting remaining acid groups with one or more component(s), wherein at least one component forms with at least said catalyst an ester compound not having a ?-hydroxy group or forms an amid compound. The component that reacts with the acidic (trans)esterification catalyst preferably is selected from the group consisting of an oxetane component or derivative, an ortho-ester component, an alcohol component or any mixture thereof.

Abstract: (Meth)acrylates are prepared by reacting (meth)acrylic acid with an alcohol in the presence of at least one acidic catalyst and at least one polymerization inhibitor in a reaction zone b) consisting of at least one reactor b1) having at least one connected distillation unit b2), by a process in which

Abstract: A method for distilling (meth)acrylic acid and/or the ester thereof by withdrawing vapor generated in a distillation column by distillation from the top of the column, condensing the vapor to give a condensate, and circulating part of the condensate as reflux liquid into the distillation column from the top thereof, comprising the step of adding a polymerization inhibitor to said condensate and said reflux liquid. This method enables maintaining the purity and quality of (meth)acrylic acid and/or the ester thereof at a certain level or higher, suppressing generation of polymers in the rectification column and suppressing polymerization of the condensate obtained by distillation in the incident facilities of the column such as condenser, condensate tank, and the like. In addition, the method enables reduction in the amount of polymerization inhibitor used while suppressing polymerization in the intermediate distillation columns (except the final rectification column).

Abstract: Polymerizable compounds are prepared and/or worked up using at least one liquid ring pump by a process in which a working liquid which contains a material stream from the preparation and/or working-up of the polymerizable compound is used in a liquid ring pump.

Abstract: An antifoulant composition comprising (meth)acrylic acid and one or more (meth)acrylate or (meth)acrylamide antifoulant polymers and a method of preventing fouling in (meth)acrylic acid processes comprising adding the (meth)acrylate or (meth)acrylamide antifoulant polymers to the (meth)acrylic acid process stream.

Abstract: A process for the manufacture of methyl methacrylate includes a process for separating the methyl methacrylate from certain impurities, at least one of which has a freezing point of greater than −50° C., by a fractional crystallisation process.

Abstract: The present invention provides a process for producing a (meth)acrylic ester which enables to obtain a (meth)acrylic ester in an excellent reaction yield. The process for producing a (meth)acrylic ester uses an alcohol and an acid as raw materials and an ion-exchange resin as a catalyst, and the process is characterized by comprising a dehydration step and an esterification step, wherein the esterification reaction step follows the dehydration step in which water impregnated in the ion-exchange resin is removed by using as a dehydrating solvent at least one member selected from the group consisting of the alcohol, the acid, and the resulting ester.

Abstract: An ester of an &agr;,&bgr;-unsaturated carboxylic acid is prepared by reacting the carboxylic acid with a C6-C12-alkanol, cyclopentanol or cyclohexanol in the presence of an acidic esterification catalyst and of an entraining agent for removing the water of reaction formed in the esterification, by a process in which the entraining agent used is the olefin on which the alkanol is based.

Abstract: When carrying out a liquid-phase reaction by using a heterogeneous catalyst, the separation of the heterogeneous catalyst and the reaction liquid is carried out certainly and effectively. A reaction method involves carrying out a reaction in liquid phase by using a heterogeneous catalyst particle 30 in a reactor 10, and comprises the steps of: (a) allowing a reaction liquid 40 supplied into the reactor 10 from such as a supplying inlet 12 to react in the presence of the heterogeneous catalyst particle 30, and (b) passing the resultant reaction liquid 40 containing the heterogeneous catalyst particle 30 through a line screen 20 having an opening width where the heterogeneous catalyst particle 30 is not allowed to pass substantially, and then extracting the reaction liquid 40 separated from the heterogeneous catalyst particle 30 from the reactor 10 by way of such as an extracting outlet 14.

Abstract: Crude butyl acrylate streams, e.g., from the reaction of butanol and acrylic acid, are refined using a splitter distillation column to yield a butyl acrylate- and heavies-containing bottoms fraction and an overhead fraction containing dibutyl ether, butyl acetate, butanol and butyl acrylate. The bottoms fraction is then subjected to separation, e.g., by distillation, to separate heavies from the bottoms fractions and to recover butyl acrylate.

Abstract: 2-Ethylhexyl acrylate is obtained by esterification of acrylic acid (AA) with 2-ethylhexanol (2-EtHexOH), in the presence of at least one stabilizer for AA, with H2SO4 as catalyst, the crude reaction mixture (B1) obtained comprising the desired acrylate, 2-EtHexOH, AA, 2-ethylhexyl hydrogensulphate (2-EtHexSO4H), traces of H2SO4 and impurities.

Abstract: The process for the esterification of (meth)acrylic acid with an alkanol in the presence of an esterification catalyst, in which unconverted starting compounds and the (meth)acrylate to be formed are separated off by distillation and an oxyester-containing bottom product is formed and is separated off, and (a) in the bottom product separated off, the oxyesters present are cleaved, if required after the addition of (meth)acrylic acid and/or oligomeric (meth)acrylic acid, directly in the presence of acid catalysts differing from (meth)acrylic acid and/or oligomeric (meth)acrylic acid, and the cleavage products are removed, a cleavage residue remaining, or (b) the oxyesters are first removed by distillation from the cleavage product separated off, a distillation residue remaining, and the oxyesters removed are cleaved, if required after addition of (meth)acrylic acid and/or oligomeric (meth)acrylic acid, in the presence of acid catalysts differing from (meth)acrylic acid and/or oligomeric (meth)acrylic acid, a

Abstract: A process for preparing alkyl acrylates is disclosed. The process provides for the synthesis of alkyl (meth)acrylates, hydrolysis of process impurities into starting materials and separation of starting materials and reaction products in one reactor.

Abstract: Crude C1-C8 alkyl (meth)acrylate streams, e.g., from the reaction of butanol and (meth)acrylic acid, are refined using a splitter distillation column to yield a C1-C8 alkyl (meth)acrylate- and heavies-containing bottoms fraction and an overhead fraction containing C1-C8 alkyl acetate, C1-C8 alcohol and C1-C8 alkyl (meth)acrylate. A stream comprising a water soluble organic solvent is introduced into the splitter distillation column in an amount sufficient to prevent the formation of water layers in the splitter distillation column and thereby reduce fouling in the splitter distillation column. The bottoms fraction is then subjected to separation, e.g., by distillation, to separate heavies from the bottoms fractions and to recover C1-C8 alkyl (meth)acrylate.

Abstract: A method for washing a spent solid catalyst is disclosed which is characterized by washing the solid catalyst used for the reaction of generating an esterified compound in a device packed with the solid catalyst, distilling the cleaning fluid in a distilling part, and circulating the fraction obtained by the distillation to an esterification reactor. According to this invention, the existing apparatus used during the process for the production of an esterified compound can be adopted without any modification, the water by-produced in the reaction for production an esterified compound and an alcohol as the raw material for esterification can be used as the cleaning fluid, and these effective components can be recovered from the cleaning fluid. Thus, the stimulation from the offensive odor and the volatile component which has heretofore posed a problem during the removal of the solid catalyst is eliminated and the safety in terms of heath and in terms of operation is secured.

Abstract: In the preparation of esters of acrylic or methacrylic acid by esterification with alcohols, the interfering deposits formed on the apparatus parts by relatively high molecular weight by-products can be avoided, removed or lessened by allowing a liquid partly or wholly consisting of the alcohol used for the esterification to act on the deposits, fouled apparatus parts or on the surfaces of the apparatus parts on which deposits are easily formed, with preference being given to wetting the deposits or surfaces using suitable nozzles or cleaning sprayers.

Abstract: In a production process for a hydroxyalkyl ester, comprising the step of carrying out a reaction between a carboxylic acid and an alkylene in the presence of a catalyst, the present invention is to provide: a production process which can stop the reaction economically and sufficiently safely. In a production process which comprises the step of carrying out the reaction between a carboxylic acid and an alkylene in a reactor 1 in the presence of a catalyst so as to produce a hydroxyalkyl ester, the reaction is stopped by introducing a reaction terminating liquid 21 into the reactor 1, wherein the reaction terminating liquid comprises water in a ratio of not less than 50 weight %, and has a low temperature of −5 to 45° C.

Abstract: A process for preparing pure (meth)acrylic acid or a (meth)acrylate starting from a crude (meth)acrylic acid, which comprises the following stages: A: treating the crude (meth)acrylic acid with at least one compound which is able to remove aldehydes, to give an aldehyde-free crude (meth)acrylic acid; B: subjecting the aldehyde-free crude (meth)acrylic acid to imprecise distillation, to give a low-boiling fraction comprising (meth)acrylic acid and acetic acid and a high-boiling fraction comprising (meth)acrylic acid and high boilers; C: isolating a pure (meth)acrylic acid from the high-boiling fraction and, if desired, D: esterifying the low-boiling fraction comprising (meth)acrylic acid and acetic acid that is obtained in stage B by means of one or more alkanols, to give an esterification mixture comprising one or more (meth)acrylates, one or more acetic esters, and one or more alkanols.

Abstract: The invention relates to a process for packaging long-chain alkyl acrylates by mixing them with a sufficient amount of solvent, e.g. xylenes, ethylbenzenes or trimethylbenzenes, thereby facilitating the handling of said acrylates by reducing the melting point of the mixture.

Abstract: The present invention provides a method for stabilizing waste oil which is taken of each chemical apparatus of the manufacturing line of (meth)acryl acid and/or ester thereof, and treating the waste oil such as draining it out of the production apparatus, for example, a distillation tower from its bottom, sending and transporting it by a pump through a pipeline, and storing it in a storage tank in a simple manner while keeping the waste oil in a stable state. The waste oil can be stabilized by coexisting with solvent. The solvent used in the present invention is typically at least one selected from the group consisting of water, alcohol, ether, carboxylic acid, ketone, aromatic hydrocarbons, and aliphatic hydrocarbons.

Abstract: An improved process for the production of high quality unsaturated dimethylesters by reacting dicarboxylic anhydrides, typically maleic anhydride or phthalic anhydride, with methanol. The process is characterized by the fact that the esterification is performed in two steps, the step 1 consisting in a non catalytic reaction of formation of monomethylesters, and the step 2 consisting in the catalytic reaction of formation of dimethylesters from the monomethylester, the said catalytic reaction taking place in a reactor consisting of a multi-tray column where the liquid phase containing the mono and diester mixture flows downwards from each tray coming to contact with a progressively drier upflowing stream of vapors in countercurrent, which continuously removes the water formed in the reaction from the liquid phase. The process uses an alkylbenzene sulfonic acid with an alkyl radical containing from 10 to 13 carbon atoms as esterification catalyst.

Abstract: A process for the removal of formaldehyde species from a liquid carboxylic acid or carboxylic acid ester stream which forms a two-phase mixture with water is disclosed which comprises the step of subjecting the liquid organic mixture to at least one liquid liquid extraction stage wherein water is used as an extractant to produce an organic phase stream which is substantially formaldehyde free and an aqueous phase stream which contains substantially all of the formaldehyde in the output streams from the liquid liquid extraction. The process is particularly useful for reducing the formaldehyde content of a methyl methacrylate product stream.

Abstract: The present invention provides: a purification process for hydroxyalkyl (meth)acrylate that suppresses forming by-products such as a diester and a dimer of acrylic acid in the distillation process, and can ensure a purity of hydroxyalkyl (meth)acrylate, and can operate stably without causing troubles such as polymerization. In a purification process for hydroxyalkyl (meth)acrylate which is obtained by reacting (meth)acrylic acid and alkylene oxide in the presence of a catalyst, and removing unreacted alkylene oxide and/or (meth)acrylic acid in a reaction solution after the reaction, a distillation apparatus having a portion of a vacant column and a thin-film evaporation apparatus are used at the same time.

Abstract: The present invention provides a process for the esterification of unsaturated carboxylic acids with unsaturated alcohols, which is characterized in that esterification is performed in the presence of sterically hindered phenols and partially esterified phosphoric acids. The process according to the invention in particular avoids discoloration (blackening) of the resultant esterification products.

Abstract: An efficient process for producing a high quality 2-adamantyl (meth)acrylate of the formula (I): wherein R1 is hydrogen or methyl and R2 is hydrogen of lower alkyl, by using very common facilities and procedures, which reacting a (meth)acryloyl halide of the formula (II) wherein R1 is as defined above and X is halogen with a 2-adamantanol of the formula (III): wherein R2 is as defined above to form the 2-adamantyl (meth)acrylate of the formula (I), then treating a solution of this product in an organic solvent with active carbon, subsequently removing the active carbon, and thereafter separating a purified 2-adamantyl (meth)acrylate, is provided.

Abstract: (Meth)acrylic esters are prepared by reacting (meth)acrylic acid with a C4-C12-alkanol in the presence of sulfuric acid or a mono-C4-C12-alkyl sulfate as catalyst, wherein a) the reaction is carried out in an esterification unit which comprises a first reactor and at least one further reactor, b) a mixture of (meth)acrylic acid, C4-C12-alkanol and catalyst which contains not more than 5% by weight of water, based on the sum of the starting materials, is introduced into the first reactor, c) the esterification in the first reactor is conducted without removing ester, alkanol or water to a (meth)acrylic acid conversion of at least 40%, but only so far that the mixture remains a single phase, and d) the esterification is continued in at least one further reactor with the water formed being removed by distillation.

Abstract: A method for producing an isocyanatoalkyl (meth)acrylate substantially free of hydrolyzable chloride, comprising adding an amine and/or an imidazole and an epoxy group-containing compound and then purifying by distillation the isocyanatoalkyl (meth)acrylate until a 2-chloropropionic acid isocyanatoalkyl ester of an isocyanatoalkyl acrylate or a 2-methyl-2-chloropropionic acid isocyanatoalkyl ester of an isocyanatoalkyl methacrylate is substantially eliminated.

Abstract: A noble metal-supported article which comprises a carrier and a palladium-containing metal component supported on the carrier, which article has (A) a layer in which substantially no palladium is supported in the interior of the carrier and (B) a layer in which palladium is supported in the region from the outer surface to a depth of less than 100 &mgr;m of the carrier.

Abstract: The disclosure is a process for preparing (meth)acrylic esters by reacting (meth)acrylic acid with C4-C6-alkanols in the presence of a strong inorganic acid or of a C4-C6-monoalkyl ester of a polybasic strong acid as catalyst, which comprises removing the unconverted alkanol from the resulting reaction mixture by distillation and thereafter removing the catalyst from the resulting mixture.

Abstract: An improved process for producing n-butyl acrylate in high yield and high purity substantially free of acrylic acid, incorporates one or more of the following new process components in an acid-catalyzed esterification process for producing n-butyl acrylate: 1. A hydrolytic recovery component, wherein heavy end adducts produced during the acid-catalyzed esterification are hydrolyzed, recovered, and recycled as valuable reactants from a hydrolytic recovery unit (HRU); 2. A cracking reactor component, preferably used with the HRU, wherein additional valuable reactants are recovered and recycled after treatment in the cracking reactor; and 3. A new distillative component, wherein a crude n-butyl acrylate stream is efficiently distilled in an aqueous mode through an acrylic acid separation column, thereby providing n-butyl acrylate substantially free of acrylic acid and in high yield. The first two components also are applicable to acid-catalyzed processes producing C1 to C4 alkyl acrylates.

Abstract: A process for the production of n-butyl acrylate (BuAcA) including the steps of esterifying acrylic acid (HAcA) with a n-butanol (n-BuOH) in a reaction zone, obtaining a condensate from the overhead vapors from the reaction zone which separates into organic and aqueous phases, feeding the organic phase comprising a major portion of BuAcA and minor portions of BuOH, water and light ends impurities to a finishing fractionation zone from which is obtained a side stream of a finished high purity BuAcA and an overhead condensate comprising BuAcA, BuOH, water, and light ends, recycling most of the overhead condensate from the finishing zone to the reaction zone, feeding the remainder of such condensate to a purge recovery zone together with a stream of makeup water, obtaining an overhead condensate from the purge recovery zone which separates into organic and aqueous phases each containing a portion of light ends produced in the reaction, recycling a portion of the organic phase as reflux to the purge recovery zone

Abstract: A process is described for preparing (meth)acrylic esters by reacting (meth)acrylic acid with C4-C12-alkanols in the presence of sulfuric acid or a mono-C4-C12-alkyl sulfate as catalyst, where the catalyst is regenerated by extraction with water from the reaction mixture and the aqueous catalyst solution is recycled back to the esterification, the concentration of unreacted alkanol in the reaction mixture to be extracted being not more than 5% by weight, based on the reaction mixture to be extracted.