Production method for (METH)acrylic acid

Abstract

To provide a production method that enables (meth)acrylic acid to be produced from a raw material containing 3-hydroxycarboxylic acid and / or a condensate thereof, while suppressing polymerization of (meth)acrylic acid in a reaction vessel even in a reaction at a high temperature exceeding 100°C, thereby allowing (meth)acrylic acid to be produced with high productivity and high yield.SOLUTION: The present invention provides a production method for (meth)acrylic acid, the method comprising a reaction step of obtaining (meth)acrylic acid by reacting a raw material containing 3-hydroxycarboxylic acid and / or a condensate thereof, wherein the production method performs the reaction step under a condition in which an iron-based compound exists in a reaction liquid containing (meth)acrylic acid and 3-hydroxycarboxylic acid and / or a condensate thereof.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a method for producing (meth)acrylic acid, and more particularly to a method for producing (meth)acrylic acid from a raw material containing a 3-hydroxycarboxylic acid and / or a condensate thereof. [Background technology]

[0002] (Meth)acrylic acid is widely used industrially as a raw material for acrylic resins and hydrophilic resins. A typical method for producing (meth)acrylic acid is a two-stage oxidation method in which fossil-derived raw materials, such as propylene or isobutylene, are converted into acrolein or methacrolein by catalytic gas-phase oxidation in the presence of an oxide catalyst using a fixed-bed multi-tubular continuous reactor, and this is then further catalytically oxidized (see Patent Documents 1 to 7). However, in light of growing awareness of environmental issues in recent years, it is desirable to produce (meth)acrylic acid from renewable resources rather than from fossil resources, and attempts have been made to economically produce (meth)acrylic acid on a commercial scale using renewable resources such as biomass.

[0003] Methods for producing (meth)acrylic acid from biomass include obtaining sugars from natural products such as agricultural crops or by decomposing cellulose, etc., and then fermenting the sugars to obtain 3-hydroxycarboxylic acids such as 3-hydroxypropionic acid (hereinafter also referred to as 3HP) and 3-hydroxyisobutyric acid, and then producing acrylic acid from the 3-hydroxycarboxylic acids. Disclosed methods include a method for producing (meth)acrylic acid that includes a step of producing a composition containing a polymer of 3-hydroxycarboxylic acid and a step of carrying out a liquid-phase reaction to produce (meth)acrylic acid from the composition at a temperature exceeding 100°C (see Patent Document 8), and a method for producing acrylic acid from 3-hydroxypropionic acid using a first polymerization inhibitor having a boiling point of 30 to 200°C and a second polymerization inhibitor having a boiling point of 200°C or higher (see Patent Document 9). Many other methods for producing (meth)acrylic acid by reacting a 3-hydroxycarboxylic acid have also been disclosed (see Patent Documents 10 to 13). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2005 / 095320 [Patent Document 2] International Publication No. 2007 / 106100 [Patent Document 3] Special Publication No. 2006-518766 [Patent Document 4] Japanese Patent Application Laid-Open No. 2000-159724 [Patent Document 5] International Publication No. 2012 / 091114 [Patent Document 6] Special Publication No. 2004-532855 [Patent Document 7] International Publication No. 2011 / 002892 [Patent Document 8] Patent No. 6078447 [Patent Document 9] Korean Patent Publication No. 2023-0049853 [Patent Document 10] U.S. Patent No. 7,166,743 [Patent Document 11] U.S. Patent No. 6,897,338 [Patent Document 12] International Publication No. 2011 / 100608 [Patent Document 13] Japanese Patent Application Laid-Open No. 2015-067567 Summary of the Invention [Problem to be solved by the invention]

[0005] As mentioned above, one known method for producing (meth)acrylic acid from biomass is to obtain 3-hydroxycarboxylic acid from natural products and then dehydrate it to produce (meth)acrylic acid. However, both methods have the drawback of causing (meth)acrylic acid to polymerize inside the reactor due to the high reactivity of acrylic acid, which can lead to gel formation within the reactor, causing problems and reducing the yield of acrylic acid. To suppress this polymerization of (meth)acrylic acid inside the reactor, polymerization inhibitors are added to the reactor, but typical polymerization inhibitors are not very effective at inhibiting polymerization at high temperatures above 100°C, where the reaction rate of the dehydration reaction of 3-hydroxycarboxylic acid is high. This means that the reaction temperature has to be lowered at the expense of (meth)acrylic acid productivity.

[0006] The present invention has been made in view of the above-mentioned current situation, and aims to provide a production method for obtaining (meth)acrylic acid from a raw material containing a 3-hydroxycarboxylic acid and / or a condensate thereof, which can suppress polymerization of (meth)acrylic acid in a reactor even in a reaction at a high temperature exceeding 100°C, and can produce acrylic acid with high productivity and high yield. [Means for solving the problem]

[0007] The present inventors have investigated methods for inhibiting the polymerization of (meth)acrylic acid in a reactor in a production process for obtaining (meth)acrylic acid from a raw material containing a 3-hydroxycarboxylic acid and / or a condensate thereof. They have found that iron-based compounds, which are not normally used as polymerization inhibitors and do not inhibit the polymerization of (meth)acrylic acid in the presence of only (meth)acrylic acid, function as polymerization inhibitors for (meth)acrylic acid in the presence of 3-hydroxycarboxylic acid and / or a condensate thereof and (meth)acrylic acid. Furthermore, the present inventors have also found that iron-based compounds exhibit excellent polymerization inhibitory effects even in reactions at high temperatures exceeding 100°C, thereby enabling the production of (meth)acrylic acid with high productivity and high yield. Furthermore, they have also found suitable methods for producing hydrophilic resins and (meth)acrylic acid esters using the (meth)acrylic acid thus obtained, leading to the present invention.

[0008] That is, the present invention is as follows.

[0009] [1] A method for producing (meth)acrylic acid, comprising a reaction step of obtaining (meth)acrylic acid from a raw material containing a 3-hydroxycarboxylic acid and / or a condensate thereof, In the production method, the reaction step is carried out under conditions in which an iron-based compound is present in a reaction liquid containing a 3-hydroxycarboxylic acid and / or a condensate thereof and (meth)acrylic acid. A method for producing (meth)acrylic acid.

[0010] [2] The method for producing (meth)acrylic acid according to [1], wherein the reaction step is carried out at a temperature of 100 to 300°C.

[0011] [3] The method for producing (meth)acrylic acid according to [1] or [2], wherein the concentration of the iron-based compound in the reaction liquid is 1 to 30,000 ppm.

[0012] [4] A method for producing a hydrophilic resin using a raw material containing a 3-hydroxycarboxylic acid and / or a condensate thereof, comprising: The production method includes a reaction step of producing (meth)acrylic acid from a 3-hydroxycarboxylic acid and / or a condensate thereof in the presence of an iron-based compound in a reaction liquid containing a 3-hydroxycarboxylic acid and / or a condensate thereof and (meth)acrylic acid; a polymerization step of polymerizing the monomer component containing (meth)acrylic acid obtained in the reaction step to produce a hydrophilic resin, A method for producing a hydrophilic resin, wherein the main product obtained in the reaction step is (meth)acrylic acid.

[0013] [5] The method for producing a hydrophilic resin according to [4], wherein the hydrophilic resin is a water-absorbent resin.

[0014] [6] The method for producing a hydrophilic resin according to [4], wherein the hydrophilic resin is a cosmetic additive.

[0015] [7] A method for producing a (meth)acrylic acid ester using a raw material containing a 3-hydroxycarboxylic acid and / or a condensate thereof, comprising: The production method includes a reaction step of producing (meth)acrylic acid from a 3-hydroxycarboxylic acid and / or a condensate thereof in the presence of an iron-based compound in a reaction liquid containing the 3-hydroxycarboxylic acid and / or a condensate thereof and (meth)acrylic acid, and an esterification step of reacting the (meth)acrylic acid-containing component obtained in the reaction step with an alcohol or an epoxide to produce an ester, and the main product among the products obtained in the reaction step is (meth)acrylic acid. A method for producing a (meth)acrylic acid ester, comprising:

[0016] [8] The (meth)acrylic acid ester may be methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, 1-octyl (meth)acrylate, 2-octyl (meth)acrylate, isononyl (meth)acrylate, isobornyl (meth)acrylate, isoamyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, or lauryl (meth)acrylate. The method for producing a (meth)acrylic acid ester according to [7], characterized in that the (meth)acrylic acid ester is any one of stearyl (meth)acrylate, cyclohexyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate, or an ester of 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, trimethylolpropane, pentaerythritol, glycerin, polyethylene glycol, and polypropylene glycol in which some or all of the alcohol groups are esterified with (meth)acrylic acid. [Effects of the Invention]

[0017] The method for producing (meth)acrylic acid of the present invention can effectively suppress the polymerization reaction of (meth)acrylic acid in a reactor even at high reaction temperatures exceeding 100°C, and is a useful method for producing (meth)acrylic acid from biomass raw materials with high productivity and high yield, stably over a long period of time. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is a diagram of a reaction apparatus used to prepare a reaction solution used in a test tube polymerization test in Preparation Example 1. [Figure 2] FIG. 1 is a diagram of a test apparatus used in tests to confirm the effects of various polymerization inhibitors in Example 1. DETAILED DESCRIPTION OF THE INVENTION

[0019] The present invention will be described in detail below. In addition, a combination of two or more of the individual preferred embodiments of the present invention described below is also a preferred embodiment of the present invention.

[0020] 1. Method for producing (meth)acrylic acid <Reaction process> The method for producing (meth)acrylic acid of the present invention includes a reaction step of obtaining (meth)acrylic acid from a raw material containing a 3-hydroxycarboxylic acid and / or a condensate thereof, and is characterized in that the reaction step is carried out under conditions in which an iron-based compound is present in a reaction solution containing a 3-hydroxycarboxylic acid and / or a condensate thereof and (meth)acrylic acid. The reaction here refers to a reaction including, as a reaction pathway, at least one of a dehydration reaction (intramolecular dehydration reaction and intermolecular dehydration reaction) of a 3-hydroxycarboxylic acid and / or a condensate thereof and a reaction of thermally decomposing a condensate of a 3-hydroxycarboxylic acid. As described above, the iron-based compound does not exhibit a polymerization inhibitory effect in the presence of only (meth)acrylic acid, whereas it exhibits a polymerization inhibitory effect on (meth)acrylic acid in an environment in which 3-hydroxycarboxylic acid and / or a condensate thereof coexists with (meth)acrylic acid.

[0021] Examples of iron-based compounds used in the method for producing (meth)acrylic acid of the present invention include iron oxide, iron sulfate, iron acetate, and iron chloride, and one or more of these can be used. Among these, iron oxide, iron sulfate, and iron acetate are preferred. Iron oxide and iron acetate, which have excellent corrosion resistance, are more preferred.

[0022] The amount of the iron-based compound used in the method for producing (meth)acrylic acid of the present invention is not particularly limited as long as the polymerization reaction of (meth)acrylic acid is suppressed, but it is preferably an amount that results in a concentration of the iron-based compound in the reaction solution of 1 to 30,000 ppm, more preferably an amount that results in a concentration of 10 to 10,000 ppm, even more preferably an amount that results in a concentration of 50 to 5,000 ppm, and most preferably an amount that results in a concentration of 100 to 5,000 ppm.

[0023] In the method for producing (meth)acrylic acid of the present invention, the temperature of the reaction step for obtaining (meth)acrylic acid from raw materials containing 3-hydroxycarboxylic acid and / or a condensate thereof is not particularly limited as long as the reaction proceeds, but is preferably 100 to 300°C. Since iron-based compounds sufficiently exhibit the polymerization inhibitory effect of (meth)acrylic acid even at such high reaction temperatures, such reaction temperatures can be adopted in the reaction step, thereby enabling the production of (meth)acrylic acid with higher productivity. The temperature of the reaction step is more preferably 110 to 220°C, and even more preferably 120 to 180°C.

[0024] The pressure inside the reactor in which the reaction step is carried out is not particularly limited as long as the reaction proceeds, but is preferably 5 to 101 kPa, more preferably 7 to 80 kPa, and even more preferably 10 to 60 kPa.

[0025] The reaction time is not particularly limited, but when the raw material composition is not continuously supplied to the reactor, the reaction time is preferably 0.5 to 200 hours, more preferably 1 to 150 hours, and even more preferably 3 to 100 hours, in consideration of the production efficiency and yield of (meth)acrylic acid.

[0026] The reaction time is not particularly limited, but when the raw material composition is continuously fed to the reactor and the reaction product is continuously withdrawn, the residence time is preferably 1 to 700 hours, more preferably 8 to 600 hours, and even more preferably 15 to 500 hours. The residence time can be determined by the following calculation formula. Residence time = (amount of liquid phase in reactor) / (amount of liquid phase withdrawn from reactor per unit time)

[0027] The reactor used in the reaction step does not require complicated equipment as long as it can be heated. Thus, one of the advantageous effects of the method for producing (meth)acrylic acid of the present invention is that the reaction can be carried out using a relatively simple device. The reactor preferably has a structure that efficiently transfers heat to the raw material composition supplied in a liquid state. Examples of such reactors include horizontal or vertical pipe natural circulation heaters, forced circulation heaters, multi-tube heat exchangers, thin film heat exchangers, etc. Alternatively, a heating system using a jacket on the outside of the reactor or a coil installed inside the reactor may be used in combination.

[0028] The reaction step in the production method of the present invention is preferably carried out by a method in which a certain amount of liquid phase is held in a heater, a reaction to produce (meth)acrylic acid is carried out in the liquid phase while the raw material composition is supplied thereto in liquid form, and the produced (meth)acrylic acid is evaporated and distilled out of the reactor. By extracting (meth)acrylic acid, a low-boiling component, in a gaseous state, unreacted oligomers that have not been decomposed sufficiently remain in the reaction liquid, thereby improving the yield of (meth)acrylic acid. The residence time required for the production of (meth)acrylic acid can be controlled by the temperature, pressure, amount of heat, feed rate of the raw material composition, and the amount of liquid-phase raw material present in the reactor. In addition, a distillation column may be installed in the reactor to apply reflux in order to suppress the distillation of 3-hydroxycarboxylic acid and / or its condensates and (meth)acrylic acid polymers. When distillation is performed, (meth)acrylic acid and water are recovered from the reaction liquid.

[0029] The reaction process may be carried out under air or an inert gas atmosphere. However, when a distillation column is installed in the reactor, it is preferably carried out under air. Oxygen can be additionally used to suppress polymerization in the distillation column. For example, it is particularly preferred to introduce an oxygen-containing gas mixture into the reaction product, the oxygen content of which in the gas phase is 18% by volume or less, preferably 5% by volume or less, which is below the explosion limit. Inert gas-oxygen mixtures, such as nitrogen-oxygen, argon-oxygen, or carbon dioxide-oxygen mixtures, can also be used.

[0030] The reaction step may be carried out by adding a base. The base to be added is not particularly limited, but examples thereof include metal compounds such as metal hydroxides and carbonates, and ammonia. Examples of metal compounds include metal compounds of Group 1 and Group 2 metals in the periodic table. Among these, the base to be added is preferably a metal compound of Group 1 metal in the periodic table, i.e., an alkali metal compound. More preferably, it is a hydroxide or carbonate of an alkali metal.

[0031] The reaction step may be carried out using a catalyst, such as the acid catalysts and base catalysts described below, with solid acid catalysts and solid base catalysts being particularly preferred. Crystalline metallosilicates such as zeolites; crystalline metallosilicates supported by methods such as ion exchange with alkali metals, alkaline earth metals, transition metals, etc.; natural or synthetic clay compounds such as kaolinite, bentonite, and montmorillonite; sulfuric acid, heteropolyacid, phosphoric acid, or phosphates (alkali metal salts of phosphoric acid, alkaline earth metal salts, manganese phosphate, zirconium phosphate, etc.), alkali metals, alkaline earth metals supported on supports such as alumina or silica. inorganic oxides or inorganic composite oxides such as Al2O3, SiO2, TiO2, ZrO2, SnO2, V2O5, SiO2-Al2O3, SiO2-TiO2, SiO2-ZrO2, TiO2-WO3, and TiO2-ZrO2; solid acidic substances such as metal sulfates and phosphates such as MgSO4, Al2(SO4)3, K2SO4, AlPO4, and Zr(SO4)2; and solid basic substances such as calcium oxide, magnesium oxide, and hydrotalcite. Suitable catalysts include Al2O3, SiO2, SiO2-Al2O3, TiO2, zeolite, and zeolite supported with an alkali metal or alkaline earth metal, and catalysts in which phosphoric acid, phosphates, alkali metals, or alkaline earth metals are supported on a support such as silica.

[0032] In the method for producing (meth)acrylic acid of the present invention, the method for supplying the iron-based compound to the reactor in which the reaction step is carried out is not particularly limited. The iron-based compound may be supplied to the reactor before the reaction raw materials, 3-hydroxycarboxylic acid and / or a condensate thereof, are supplied to the reactor, or may be supplied simultaneously with the supply of 3-hydroxycarboxylic acid or a condensate thereof to the reactor, or may be supplied successively during the reaction. The iron-based compound may be fed directly to the reactor, or, when a distillation column is installed in the reactor, may be fed from the distillation column.

[0033] <3-Hydroxycarboxylic acid and method for producing same> The 3-hydroxycarboxylic acid used in the present invention includes 3-hydroxypropionic acid, 3-hydroxyisobutyric acid, etc., and any of these may be used, but since acrylic acid obtained by reacting 3-hydroxypropionic acid is particularly highly reactive and easily polymerized, the technical significance of using the production method of the present invention is more fully realized when 3-hydroxypropionic acid is used as the 3-hydroxycarboxylic acid. Therefore, using 3-hydroxypropionic acid as the 3-hydroxycarboxylic acid is one of the preferred embodiments of the present invention.

[0034] The 3-hydroxycarboxylic acid used in the present invention can be obtained from various sources, but from the viewpoint of suppressing global warming and protecting the environment, it is preferable to obtain it from a biological resource that can be recycled as a carbon source. Specifically, it can be prepared by further fermenting sugars obtained from agricultural crops or sugars obtained by decomposing cellulose or the like. In the present invention, it is preferable that at least a part or all of the 3-hydroxycarboxylic acids contained in the raw material composition are 3-hydroxycarboxylic acids obtained by fermentation. That is, the method for producing (meth)acrylic acid of the present invention preferably includes a fermentation step, and is a production method in which a 3-hydroxycarboxylic acid is produced as a raw material by the fermentation step. Furthermore, the raw material for 3-hydroxycarboxylic acid is preferably a biological resource such as biomass.

[0035] Known methods can be used to obtain 3-hydroxycarboxylic acids from biological resources. For example, a method described in WO 2008 / 027742 can be used, in which Escherichia coli introduced with the beta-alanine aminotransferase gene derived from Streptomyces griseus ATCC21897 is subjected to fermentation using glucose as a carbon source. Alternatively, a method described in WO 2001 / 016346 can be used, in which Escherichia coli introduced with glycerol dehydratase derived from Klebsiella pneumoniae and aldehyde oxidase derived from Escherichia coli is subjected to fermentation using glycerol as a carbon source.

[0036] Although the above-mentioned known literature has been described as an example of a method for obtaining 3-hydroxycarboxylic acid, the microorganism or genetically modified microorganism used for fermentation is not particularly limited, and any 3-hydroxycarboxylic acid obtained by fermentation using an organism capable of producing 3-hydroxycarboxylic acid can be used in the production method of the present invention. Furthermore, 3-hydroxycarboxylic acid produced by contacting a raw material sugar with an organism other than fermentation can also be converted to (meth)acrylic acid by the production method of the present invention.

[0037] When a raw material composition containing a 3-hydroxycarboxylic acid and / or a condensate thereof obtained from a biological resource is used as a raw material for the production method of the present invention, the raw material composition is preferably obtained through a fermentation process and contains fewer impurities. Examples of impurities in the raw material composition obtained through a fermentation process include bacteria, proteins, amino acids, glucose, salts, etc. that are typically contained in a fermentation broth, and by-products that may be produced together with the 3-hydroxycarboxylic acid during fermentation, such as formic acid, acetic acid, propionic acid, butyric acid, succinic acid, fumaric acid, pyruvic acid, glycolic acid, lactic acid, ethanol, amino acids, 1,3-propanediol, glycerin, hydroxypropionaldehyde, and alanine.

[0038] A method for obtaining a raw material composition containing 3-hydroxycarboxylic acid and / or a condensate thereof with few impurities includes a method for preparing the raw material composition using 3-hydroxycarboxylic acid that has been purified from a fermentation broth. Known methods can be used for the purification step from the fermentation broth. Specifically, a method in which crude 3-hydroxycarboxylic acid obtained by fermentation is precipitated using a calcium salt, and the calcium salt of 3-hydroxycarboxylic acid is recovered and then reacted with an acid such as sulfuric acid to purify the 3-hydroxycarboxylic acid; a method in which ammonium-type 3-hydroxycarboxylic acid obtained by fermentation is chemically converted to 3-hydroxycarboxylic acid by electrodialysis or cation exchange, followed by purification; etc. can be used. Furthermore, membrane separation operations can be used, such as removing impurities using ordinary filter cloth, MF membranes (microfiltration membranes), or UF membranes (ultrafiltration membranes), or concentrating 3-hydroxycarboxylic acids using RO membranes (reverse osmosis membranes). Alternatively, an amine solution of 3-hydroxycarboxylic acid can be extracted by adding a water-immiscible amine solvent to an aqueous solution of 3-hydroxycarboxylic acid or its ammonium salt obtained by fermentation and heating as necessary. Water can then be added to the solution and back-extracted by heating to obtain an aqueous solution of 3-hydroxycarboxylic acid. Alternatively, the 3-hydroxycarboxylic acid can be purified by evaporation or distillation, taking advantage of its vapor pressure. However, because the vapor pressure of 3-hydroxycarboxylic acid is low, operations under high vacuum are preferred. Furthermore, purified 3-hydroxycarboxylic acids can also be obtained by esterifying 3-hydroxycarboxylic acids with alcohols, purifying and concentrating the resulting 3-hydroxycarboxylic acid esters by distillation, and then hydrolyzing the 3-hydroxycarboxylic acid esters. Alternatively, the aqueous solution of 3-hydroxycarboxylic acid can be concentrated by removing water by evaporation or distillation, for example, by using a multi-effect reactor.

[0039] A condensation product of 3-hydroxycarboxylic acid is a polymer in which 3-hydroxycarboxylic acids are linked together via intermolecular ester bonds, and a condensation product of 3-hydroxypropionic acid can be represented by the following formula (1).

[0040] [ka]

[0041] (In formula (1), n ​​represents a number of 1 or more.) In the above formula (1), n ​​is preferably 1 to 20, and more preferably 1 to 10.

[0042] In the present invention, the raw material for the reaction step may be a composition containing a 3-hydroxycarboxylic acid and / or a condensate thereof and a solvent. Examples of the solvent include water, alcohols, hydrocarbons, ethers, ketones, esters, amines, amides, etc., and these can be used alone or in combination of two or more. Among these, solvents having a boiling point lower than that of 3-hydroxycarboxylic acid are preferred in that the solvent can be easily evaporated, and for example, water is preferred.

[0043] When the raw material for the reaction step is a composition containing a 3-hydroxycarboxylic acid and / or a condensate thereof and a solvent, the concentration of the 3-hydroxycarboxylic acid and / or a condensate thereof in the composition is preferably 20 to 100% by mass, more preferably 30 to 99% by mass, and even more preferably 40 to 98% by mass, based on 100% by mass of the composition.

[0044] In the present invention, the raw materials for the reaction step may contain components other than the 3-hydroxycarboxylic acid and / or its condensate and the solvent, such as by-products produced when synthesizing the 3-hydroxycarboxylic acid by fermentation or the like.

[0045] The content of components other than 3-hydroxycarboxylic acid and / or its condensate and solvent contained in the raw materials for the reaction step used in the present invention is preferably 5% by mass or less, more preferably 3% by mass or less, and even more preferably 1% by mass or less, based on 100% by mass of the raw materials.

[0046] <Other processes> The method for producing (meth)acrylic acid of the present invention may include other steps as long as it includes a reaction step for obtaining (meth)acrylic acid from a raw material containing a 3-hydroxycarboxylic acid and / or a condensate thereof. Examples of such other steps include a step of recovering a reaction liquid containing the (meth)acrylic acid obtained in the reaction step, and a step of purifying the (meth)acrylic acid obtained in the reaction step. The purification step can be carried out by a method such as membrane separation, distillation, extraction, or crystallization.

[0047] The method for recovering the reaction solution containing (meth)acrylic acid obtained in the above reaction step is not particularly limited, but recovery by distillation is preferred. The distillation recovery solution contains (meth)acrylic acid, which is the main reaction product, and may also contain by-products, the solvent in the raw material composition, and impurities. When the solvent is water, the (meth)acrylic acid can be used as a raw material for polymer production in the form of an aqueous solution. Furthermore, by adding a purification step, high-purity (meth)acrylic acid can be obtained. The purification step can be carried out by known techniques such as membrane separation, distillation, extraction, crystallization, etc., or a combination of these. Among these, the purification step is preferably a step of purifying (meth)acrylic acid by distillation or crystallization.

[0048] 2. Manufacturing method of hydrophilic resin and uses of hydrophilic resin (Meth)acrylic acid can be produced by the above-mentioned method. The (meth)acrylic acid thus produced can be used as a raw material for hydrophilic resins such as water-absorbent resins or water-soluble resins. In other words, one aspect of the present invention is to use the (meth)acrylic acid obtained by the production method of the present invention as a raw material for producing a hydrophilic resin. The method for producing a hydrophilic resin of the present invention includes the above-mentioned reaction step and a polymerization step of polymerizing a monomer component containing (meth)acrylic acid to produce a hydrophilic resin, and is characterized in that the main product among the products obtained in the reaction step is (meth)acrylic acid. The (meth)acrylic acid obtained by the method for producing (meth)acrylic acid of the present invention has high quality with few impurities and the polymerization reaction is easy to control. Furthermore, using this (meth)acrylic acid as a raw material stabilizes the quality of the hydrophilic resin and improves various properties such as water absorption capacity and inorganic material dispersion capacity. The method for carrying out the polymerization step to produce the hydrophilic resin is not particularly limited, and a method in which an initiator and other components are added to a monomer component containing (meth)acrylic acid and the polymerization reaction is allowed to proceed by heating or other methods can be used.

[0049] Furthermore, the (meth)acrylic acid obtained by the production method of the present invention can be suitably used for producing various (meth)acrylic acid derivatives, and the (meth)acrylic acid derivatives can be produced by carrying out a step for producing various (meth)acrylic acid derivatives (derivative production step) after the above-mentioned reaction step. A purification step may or may not be carried out between the reaction step and the derivative production step. The purity of the (meth)acrylic acid used in the derivative production step is not particularly limited.

[0050] Examples of the (meth)acrylic acid derivatives include (meth)acrylic acid esters and polymers thereof, (meth)acrylic acid salts and polymers thereof, and the like. Specific examples of (meth)acrylic acid esters include esters of (meth)acrylic acid such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, 2-ethylhexyl, 1-octyl, 2-octyl, isononyl, isobornyl, isoamyl, 2-methoxyethyl, 2-ethoxyethyl, tetrahydrofurfuryl, lauryl, stearyl, cyclohexyl, 2-hydroxyethyl, 2-hydroxypropyl, and 4-hydroxybutyl, as well as esters in which a portion or all of the alcohol groups of polyhydric alcohols such as 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, trimethylolpropane, pentaerythritol, glycerin, polyethylene glycol, and polypropylene glycol are esterified with (meth)acrylic acid. Additionally, examples include esters in which various alcohols are modified with ethylene oxide and / or propylene oxide and then partially or completely esterified with (meth)acrylic acid, as well as esters such as 2-(vinyloxyethoxy)ethyl, α-(hydroxymethyl)methyl, and α-(allyloxymethyl)methyl. Specific examples of (meth)acrylate salts include sodium, potassium, calcium, magnesium, ammonium, and zinc salts.

[0051] The above (meth)acrylic acid esters and (meth)acrylic acid salts can be (co)polymerized alone or in combination to produce various polymers. Examples of the polymers include poly(meth)acrylic acid esters, poly(sodium meth)acrylic acid, and crosslinked products thereof. Examples of the crosslinked products include water-absorbent resins and slightly crosslinked resins (commonly called carbomers). The (meth)acrylic acid obtained by the method for producing (meth)acrylic acid of the present invention is useful as a raw material for synthesizing (meth)acrylic acid derivatives such as (meth)acrylic acid esters; water-absorbing resins such as poly(meth)acrylic acid and sodium poly(meth)acrylate; etc.

[0052] The (meth)acrylic acid and hydrophilic resin produced by the present invention, as well as the various (meth)acrylic acid derivatives described above, are of high quality and can be suitably used in a wide range of applications, including building materials, optical applications, automobiles, detergents, disposable diapers, sanitary materials, food applications, cosmetics, and pharmaceuticals, and can be used as adhesives, pressure-sensitive adhesives, paints, coating agents, inks, superabsorbent resins, thickeners, water-retaining materials, vibration-damping materials, acrylic rubbers, acrylic fibers, acrylic resins, acrylic emulsions, molding resins, electronics materials, reactive diluents, and pharmaceutical raw materials. (Meth)acrylic acid derivatives such as (meth)acrylic acid esters are used in a wide range of applications, including building materials and optical applications. Other applications include printing ink solvents, printing ink compositions and ink cleaners for printing machines, plastic additives, antistatic agents, biodiesel, fuels and their additives, electrical insulating oils, lubricating oils, spilled oil recovery agents, industrial cleaners, paint solvents, urethane viscosity reducers, adhesive solvents, solvents for reactions, separation, purification, and extraction, and solvents for the textile industry.

[0053] The above-mentioned water-absorbent resins are water-swellable, water-insoluble polymer gelling agents, and are used for a variety of purposes, including absorbent articles such as disposable diapers and sanitary napkins, soil water retention agents for agricultural and horticultural use, and industrial water-stopping agents. Although many types of monomers and water-absorbent polymers are used as raw materials for the water-absorbent resins, polyacrylic acid (salt)-based water-absorbent resins using acrylic acid and / or its salts (hereinafter referred to as "acrylic acid (salt)") as a monomer are most commonly used from the viewpoint of the water-absorbing performance and production costs of the water-absorbent resins. The use of the water-absorbent resin is not particularly limited, but preferred examples include absorbent materials for absorbent articles such as disposable diapers (for infants and adults), sanitary napkins, and incontinence pads. In particular, the water-absorbent resin can be used as an absorbent material for high-concentration disposable diapers. The absorbent body may contain an absorbent material such as pulp fiber in addition to the water-absorbent resin of the present invention. In this case, the amount of the water-absorbent resin in the absorbent body (hereinafter referred to as "core concentration") is preferably 30% by weight to 100% by weight, more preferably 40% by weight to 100% by weight, even more preferably 50% by weight to 100% by weight, still more preferably 60% by weight to 100% by weight, particularly preferably 70% by weight to 100% by weight, and most preferably 75% by weight to 95% by weight.

[0054] Examples of other absorbent articles include drip absorbers, freshness-preserving materials, portable toilets for disasters, pet sheets, cat litter, etc. Other uses of water-absorbent resins include soil water retention agents, seedling raising sheets, seed coating materials, anti-condensation sheets, disposable warmers, cooling bandanas, ice packs, medical waste liquid solidifying agents, surplus soil solidifying materials, water-damage preventing waste liquid gelling agents, water-absorbing sandbags, compresses, thickeners for cosmetics, water-stopping materials for communication cables of electric and electronic materials, gasket packing, sustained-release agents for fertilizers, various sustained-release agents (space disinfectants, air fresheners, etc.), wound protection dressings, anti-condensation building materials, oil moisture removers, paints, adhesives, anti-blocking agents, light diffusing agents, matting agents, additives for resins such as additives for decorative panels, additives for artificial marble, and additives for toner.

[0055] The method for producing (meth)acrylic acid of the present invention can naturally be incorporated into the production of (meth)acrylic acid derivatives and water-absorbent resins, and such methods for producing water-absorbent resins also constitute the present invention. That is, the present invention also provides a method for producing a water-absorbent resin using 3-hydroxycarboxylic acid as a raw material, the method comprising: a step of reacting a raw material containing 3-hydroxycarboxylic acid and / or a condensate thereof to obtain (meth)acrylic acid; and a polymerization step of polymerizing a monomer component containing the (meth)acrylic acid to produce a water-absorbent resin, wherein the main product among the products obtained in the reaction step is (meth)acrylic acid. Here, "the main product in the product obtained in the reaction step is (meth)acrylic acid" means that the proportion of (meth)acrylic acid produced is 50% by mass or more relative to the total mass of the product obtained in the reaction step. The proportion of (meth)acrylic acid in the product obtained in the reaction step is more preferably 65% ​​by mass or more, and even more preferably 80% by mass or more.

[0056] The method for producing a water absorbent resin of the present invention includes a step of polymerizing a monomer component containing (meth)acrylic acid obtained from 3-hydroxycarboxylic acid and / or a condensate thereof, and when the non-petroleum-based acrylic acid alone does not meet the required production amount of the water absorbent resin due to the production amount (supply amount) or trace amount of components, petroleum-based (meth)acrylic acid may be used in combination as necessary. When non-petroleum-based (meth)acrylic acid and petroleum-based (meth)acrylic acid are used in combination, the mass ratio is determined within a range of 0 / 100 to 100 / 0, preferably 5 / 95 to 100 / 0, and more preferably 10 / 90 to 100 / 0.

[0057] The hydrophilic resin obtained by polymerizing the (meth)acrylic acid obtained by the method for producing (meth)acrylic acid of the present invention can also be used as an additive for cosmetics. [Cosmetic additives] The hydrophilic resin used as a cosmetic additive may be a crosslinked polymer obtained by crosslinking polymerizing, as needed, a monomer composition containing as a main component (meth)acrylic acid obtained by the method for producing (meth)acrylic acid of the present invention, and may also contain a graft component. The hydrophilic resin used as a cosmetic additive is obtained by polymerizing a monomer composition containing as a main component (meth)acrylic acid obtained by the method for producing (meth)acrylic acid of the present invention, and the monomer composition may essentially consist of only acrylic acid as a monomer, or may contain other monomers copolymerizable with acrylic acid. The other monomers are not particularly limited, but examples thereof include methacrylic acid, maleic acid, itaconic acid, 2-(meth)acrylamido-2-methylpropanesulfonic acid, (meth)acrylamide, and salts thereof. These monomers may be used alone or in combination of two or more. Among them, itaconic acid is preferred when used in combination with other monomers because it can be obtained by fermentation and contributes to the use of bio-based raw materials.

[0058] From the viewpoint of the performance of the cosmetic additive, the proportion of acrylic acid (salt) in the monomer composition is preferably 50 to 100 mol%, more preferably 70 to 100 mol%, and even more preferably 90 to 100 mol%, relative to the total amount of monomers (100% by mass). The proportion of the other monomers in the monomer composition is, for example, 0 to 50 mol%, and preferably 5 to 45 mol%.

[0059] When the crosslinking polymerization is carried out, a crosslinking agent is used, which may be added before or after the polymerization of the monomer composition. Examples of the crosslinking agent include ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, trimethylolpropane di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra ... Examples of such compounds include compounds having two or more ethylenically unsaturated groups in one molecule, such as tall triallyl ether neoallyl, N,N'-methylenebis(meth)acrylamide, triallyl isocyanurate, trimethylolpropane di(meth)allyl ether, triallylamine, tetraallyloxyethane, and glycerolpropoxy triacrylate. Preferred are compounds having two ethylenically unsaturated groups in one molecule, such as ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, and triethylene glycol di(meth)acrylate. The crosslinking agent may be used alone or in combination of two or more.

[0060] The polymerization method for the monomer composition is not particularly limited, and any known or commonly used method can be used. Examples of the polymerization method include bulk polymerization, solution polymerization, suspension polymerization, and emulsion polymerization. Among these, precipitation polymerization is preferred from the viewpoint of achieving superior thickening properties of the cosmetic additive and superior usability of the cosmetic.

[0061] A solvent may be used in the polymerization of the monomer composition. A hydrophobic organic solvent may be used as the solvent used in the polymerization of the monomer composition. Examples of the hydrophobic organic solvent include aliphatic hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbons, aliphatic alcohols, aliphatic ketones, and aliphatic esters.

[0062] Examples of aliphatic hydrocarbons include aliphatic hydrocarbons having 5 or more carbon atoms, specifically, for example, n-pentane, n-hexane, n-heptane, and the like. Examples of the alicyclic hydrocarbon include alicyclic hydrocarbons having 5 or more carbon atoms, such as cyclopentane, methylcyclopentane, cyclohexane, and methylcyclohexane. Examples of aromatic hydrocarbons include benzene, toluene, and xylene. The aliphatic alcohol is an aliphatic alcohol having 4 or more carbon atoms, preferably 4 to 6 carbon atoms, and specific examples thereof include n-butyl alcohol and n-amyl alcohol. The aliphatic ketones include aliphatic ketones having 4 or more carbon atoms, preferably 4 to 6 carbon atoms, specifically, for example, methyl ethyl ketone. The aliphatic esters include aliphatic esters having 4 or more carbon atoms, preferably 4 to 6 carbon atoms, specifically, for example, ethyl acetate.

[0063] The above-mentioned solvents such as hydrophobic organic solvents may be used alone or in combination of two or more kinds. For example, the above-listed hydrophobic organic solvents may be used alone or in combination of two or more kinds.

[0064] As the solvent used for polymerizing the monomer composition, in terms of controlling the precipitation of the polymer, it is preferable to use at least one selected from the group consisting of aliphatic hydrocarbons and alicyclic hydrocarbons in combination with at least one selected from the group consisting of aliphatic ketones and aliphatic esters, and it is more preferable to use an alicyclic hydrocarbon in combination with an aliphatic ester.

[0065] The mass ratio of the aliphatic hydrocarbons and alicyclic hydrocarbons to the aliphatic ketones and aliphatic esters used as the solvent for polymerizing the monomer composition (total mass of aliphatic hydrocarbons and alicyclic hydrocarbons / total mass of aliphatic ketones and aliphatic esters) is preferably 0 / 100 to 50 / 50, more preferably 10 / 90 to 30 / 70, and more preferably 100 / 0 to 50 / 50, more preferably 90 / 10 to 70 / 30.

[0066] The mass ratio of the alicyclic hydrocarbon to the aliphatic ester (mass of the alicyclic hydrocarbon / mass of the aliphatic ester) used as the solvent for polymerizing the monomer composition is preferably 0 / 100 to 50 / 50, more preferably 10 / 90 to 30 / 70, and more preferably 100 / 0 to 50 / 50, more preferably 90 / 10 to 70 / 30.

[0067] A polymerization initiator can be used for polymerizing the above-mentioned monomer composition, and a radical polymerization initiator can be preferably used as the polymerization initiator. The radical polymerization initiator is preferably a thermal polymerization initiator, and examples thereof include peroxide-based polymerization initiators and azo compound-based polymerization initiators. Examples of the peroxide-based polymerization initiator include benzoyl peroxide, lauroyl peroxide, octanoyl peroxide, orthochlorobenzoyl peroxide, orthomethoxybenzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxydicarbonate, di(2-ethylhexyl)peroxydicarbonate, cumene hydroperoxide, cyclohexanone peroxide, t-butyl hydroperoxide, and diisopropylbenzene hydroperoxide. Furthermore, examples of the azo compound polymerization initiator include 2,2'-azobisisobutyronitrile, 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2,3-dimethylbutyronitrile), 2,2'-azobis-(2-methylbutyronitrile), 2,2'-azobis(2,3,3-trimethylbutyronitrile), 2,2'-azobis(2-isopropylbutyronitrile), 1,1'-azobis(cyclohexane-1-carbonitrile), 2,2'-4-methoxy-2,4-dimethylvaleronitrile), 2-(carbamoylazo)isobutyronitrile, 4,4'-azobis(4-cyanovaleric acid), and dimethyl-2,2'-azobisisobutyrate. The polymerization initiators may be used alone or in combination of two or more.

[0068] By carrying out a step of drying the hydrophilic resin, the cosmetic additive can be obtained as a powder. Drying may be carried out under normal pressure or under reduced pressure. The drying temperature is, for example, 60 to 120°C, and preferably 80 to 110°C. If the drying temperature is 120°C or lower, deterioration of the hydrophilic resin is less likely to occur, and a decrease in viscosity and a deterioration in feel to the touch can be less likely to occur. If the drying temperature is 60°C or higher, the productivity of the drying step is good and the solvent can be sufficiently removed.

[0069] From the viewpoint of productivity when precipitation polymerization is performed, the neutralization rate of the acid groups of the hydrophilic resin is preferably 50 mol% or less, more preferably 30 mol% or less, even more preferably 10 mol% or less, and particularly preferably 5 mol% or less, and may be an embodiment in which no neutralization is performed (neutralization rate is 0 mol%). Neutralization may be performed on the monomer (monomer composition containing (meth)acrylic acid), on the hydrophilic resin after polymerization, or on both. Examples of the neutralized salt include alkali metal salts such as sodium, potassium and lithium salts of (poly)acrylic acid, ammonium salts, and amine salts.

[0070] The hydrophilic resin (cosmetic additive) obtained by polymerizing (meth)acrylic acid obtained by the production method of the present invention may be subjected to a classification step to make the particle size uniform after passing through a polymerization step or a drying step.

[0071] (transparency) Cosmetic additives that do not cause turbidity are preferred. Transparent cosmetic products and products with various visual effects have been developed, and as long as the cosmetic additive does not cause turbidity, the visual effect can be freely selected.

[0072] (Feel of using cosmetics) Cosmetic additives that have a fresh feel when used are preferred. The feel of the cosmetic when used and the texture when applied to the skin are important characteristics of the cosmetic. There are a variety of options, including a fresh and light feel and a moist and heavy feel. Among these, there are few cosmetic additives that can provide a fresh and light feel, and there is a high demand in the market. A less preferred feel is a sticky feel, which many people find unpleasant.

[0073] The cosmetic additive of the present invention can be used as a known or conventional cosmetic additive. Examples of the additive include thickeners, gelling agents, feel-improving agents, moisturizing agents, film-forming agents, UV absorbers, antibacterial agents, emulsifiers, surfactants, dispersants, etc. The additives may be used alone or in combination of two or more types, and are preferably used as thickeners, gelling agents, feel-improving agents, moisturizing agents, or film-forming agents.

[0074] [Cosmetics] Cosmetics can be produced using the cosmetic additive of the present invention. The cosmetic contains at least the cosmetic additive of the present invention. The cosmetic may contain other ingredients in addition to the cosmetic additive of the present invention.

[0075] Examples of the other ingredients include solvents (e.g., water, organic solvents, etc.), oils, lower alcohols, polyhydric alcohols, thickeners, humectants, surfactants (anionic surfactants, cationic surfactants, amphoteric surfactants, nonionic surfactants), fatty acid alkanolamides, antioxidants, antioxidant aids, powder ingredients (e.g., organic powders, pigments, colorants, etc.), natural water-soluble polymers, semi-synthetic water-soluble polymers, synthetic water-soluble polymers, chelating agents, sugars and derivatives thereof, amino acids and derivatives thereof, organic amines, polymer emulsions, pH adjusters (acids, alkalis, etc.), vitamins, preservatives, antibacterial agents, anti-inflammatory agents, various extracts, activators, blood circulation promoters, antiseborrheic agents, anti-inflammatory agents, fragrances, etc. One or more of the above other ingredients may be used.

[0076] The above-mentioned cosmetics include known or commonly used cosmetics, such as skin cosmetics, hair cosmetics, and bath cosmetics. Here, topical preparations are applied to the skin, nails, hair, etc. of the human body, and can be used to treat various diseases by incorporating active pharmaceutical ingredients, for example. Cosmetics are also applied to the skin, nails, hair, etc. of the human body, but are used for cosmetic purposes. Even when used as "topical preparations," they may actually be used in the same manner and dosage as cosmetics. Therefore, in this specification, the term "cosmetics" also includes such topical preparations. Examples of such topical preparations include antiperspirants, skin cleansers, topical skin preparations, hair cleansers, and topical hair preparations. Pharmaceutical uses of these topical preparations include hair growth agents, hair restorers, analgesics, disinfectants, anti-inflammatory agents, cooling agents, and skin anti-aging agents.

[0077] The skin cosmetics can be used on any part of the body, including the scalp, face (including lips, eyebrows, and cheeks), fingers, nails, and the entire body. Specific examples include skin cleansing products such as cleansing gel, cleansing cream, cleansing foam, facial cleanser, eye makeup remover, facial cleanser, liquid soap (body soap), hand soap, gel soap, shaving cream, nail polish remover, and acne prevention cosmetics; skin care products such as skin cream, scalp treatment, skin milk, milk lotion, emulsion, facial pack, body powder, essence, shaving lotion, and massage lotion; makeup products such as foundation, liquid foundation, oil-based foundation, makeup base, face powder, blusher, lip balm, lipstick, lip gloss, eye cream, mascara, eyebrow pencil, and eyelash cosmetics; antiperspirants such as deodorants; UV protection products such as sunscreens and suntanning agents (sun tanning agents); and deodorant products.

[0078] Examples of the hair cosmetics include eyelash cosmetics, hair cleansers such as shampoos and rinse-in shampoos, hair styling products such as hair wax, hair curl retainers, setting agents, hair creams, hair sprays, and hair liquids, hair coloring products such as hair dyes, hair color sprays, hair color rinses, and hair color sticks, hair care products such as hair tonics, hair treatment essences, and hair packs, and hair rinse or hair conditioning products such as oil rinses, cream rinses, treatment rinses, hair conditioners, and hair treatments. Examples of the bath cosmetics include foam baths.

[0079] The form of the cosmetic is not particularly limited, and may be any of a solution, emulsion, cream, solid, semi-solid, paste, gel, powder, multi-layered, mousse, water-in-oil, or oil-in-water emulsion composition (emulsion composition). The cosmetic of the present invention can be formulated by known methods in the form of, for example, a liquid, suspension, emulsion, cream, ointment, gel, liniment, lotion, aerosol, powder, spray, sheet in which a sheet such as a nonwoven fabric is impregnated with the cosmetic of the present invention, or stick.

[0080] The content of the cosmetic additive of the present invention in the cosmetic is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, and even more preferably 0.3% by mass or more, relative to the total amount (100% by mass) of the cosmetic, and is preferably 5.0% by mass or less, more preferably 3.0% by mass or less, and even more preferably 2.0% by mass or less.

[0081] 3. Method for producing (meth)acrylic acid esters The method for producing (meth)acrylic acid of the present invention can naturally be incorporated into methods for producing (meth)acrylic esters, and such methods for producing (meth)acrylic esters also constitute one aspect of the present invention. That is, a method for producing a (meth)acrylic ester using a raw material containing a 3-hydroxycarboxylic acid and / or a condensate thereof, the method comprising: a reaction step of producing (meth)acrylic acid from the 3-hydroxycarboxylic acid and / or a condensate thereof in the presence of an iron-based compound in a reaction liquid containing the 3-hydroxycarboxylic acid and / or the condensate thereof and (meth)acrylic acid; and an esterification step of reacting the (meth)acrylic acid-containing component obtained in the reaction step with an alcohol or an epoxide to produce an ester, wherein the main product among the products obtained in the reaction step is (meth)acrylic acid. Here, "the main product in the product obtained in the reaction step is (meth)acrylic acid" means that the proportion of (meth)acrylic acid produced is 50% by mass or more relative to the total mass of the product obtained in the reaction step. The proportion of (meth)acrylic acid in the product obtained in the reaction step is more preferably 65% ​​by mass or more, and even more preferably 80% by mass or more.

[0082] The conditions for the reaction step to produce the (meth)acrylic acid are as described above. The purity of the (meth)acrylic acid is not particularly limited, and a purification step may or may not be carried out after the reaction step.

[0083] The conditions for the esterification step are not particularly limited, and generally known methods can be used. Specifically, the esterification reaction may be carried out by heating in the presence of a catalyst. The catalyst can be selected from sulfuric acid, sulfonic acid, phosphoric acid, p-toluenesulfonic acid, benzenesulfonic acid, methanesulfonic acid, dodecylsulfonic acid, etc., and an acidic ion exchange resin can also be used. In addition, a basic catalyst such as sodium hydroxide, potassium hydroxide, or a basic ion exchange resin can also be used.

[0084] The reaction temperature in the esterification step can be set appropriately, but is preferably in the range of 40 to 120°C. The pressure can be set arbitrarily, such as under atmospheric pressure, reduced pressure, or increased pressure. It is also preferable to carry out the esterification step in the presence of a polymerization inhibitor, and specifically, it is preferable to use a quinone-based, phenol-based, phenothiazine-based, N-oxyl-based, metal-based or other polymerization inhibitor. The reaction can also be carried out while blowing an oxygen-containing gas into the liquid phase and / or the gas phase.

[0085] When the reaction in the esterification step is a reaction between (meth)acrylic acid and alcohol, the charging ratio of (meth)acrylic acid to alcohol is not particularly limited, but it is preferable to carry out the reaction under conditions where either (meth)acrylic acid or alcohol is in excess in order to promote the reaction. Unreacted alcohol and (meth)acrylic acid can be recovered and recycled. The reaction can also be accelerated by removing the water produced during the esterification reaction. When the reaction in the esterification step is a reaction between (meth)acrylic acid and an epoxide, the charging ratio of (meth)acrylic acid and the epoxide, the reaction method, etc. are not particularly limited, and a general method can be used.

[0086] The (meth)acrylic acid ester produced in the esterification step is preferably further purified to increase its purity before use. The method for the purification step is not particularly limited, and general methods such as distillation, extraction, crystallization, and adsorption can be used.

[0087] The resulting (meth)acrylic acid ester can be used to produce a derivative by carrying out an additional derivatization step. Specific examples of the derivatization step include transesterification with various alcohols, methylolation using formaldehyde, and etherification by further reacting the methylolated derivative with an alcohol.

[0088] The alcohol or epoxide used in the esterification step is not particularly limited, and examples of alcohols that can be used include methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, 2-ethylhexanol, 1-octanol, 2-octanol, isononyl alcohol, isobornyl alcohol, isoamyl alcohol, 2-methoxyethanol, 2-ethoxyethanol, tetrahydrofurfuryl alcohol, lauryl alcohol, stearyl alcohol, cyclohexanol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, trimethylolpropane, pentaerythritol, glycerin, polyethylene glycol, polypropylene glycol, and alcohols obtained by modifying various alcohols with ethylene oxide and / or propylene oxide. As the epoxide, ethylene oxide, propylene oxide, butylene oxide, glycidol, etc. can be used. Of these alcohols or epoxides, it is preferable to use methanol, ethanol, n-butanol, 2-ethylhexanol, 2-octanol, isobornyl alcohol, methoxyethanol, ethylene oxide, and propylene oxide, and among these, it is preferable to use those derived from biomass.

[0089] The (meth)acrylic acid ester obtainable by the method for producing a (meth)acrylic acid ester of the present invention is not particularly limited, and specific examples thereof include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, 1-octyl (meth)acrylate, 2-octyl (meth)acrylate, isononyl (meth)acrylate, isobornyl (meth)acrylate, isoamyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, Examples of the ester include tetrahydrofurfuryl acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, cyclohexyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate, as well as esters in which a portion or all of the alcohol groups in polyhydric alcohols such as 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, trimethylolpropane, pentaerythritol, glycerin, polyethylene glycol, and polypropylene glycol are esterified with (meth)acrylic acid. Further examples include esters in which a portion or all of various alcohols modified with ethylene oxide and / or propylene oxide are esterified with (meth)acrylic acid. Of these, methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, 2-octyl (meth)acrylate, isobornyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, and 2-hydroxypropyl (meth)acrylate are preferred, and among these, those derived from biomass are preferred.

[0090] Derivatives produced by subjecting the above (meth)acrylic acid esters to an additional derivatization step include the above-mentioned various (meth)acrylic acid esters, 2-(vinyloxyethoxy)ethyl (VEEA), α-(hydroxymethyl)methyl (RHMA), α-(allyloxymethyl)methyl (AOMA), and the like. When producing a derivative by transesterification, it is preferable to use an ester such as methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, or isobutyl (meth)acrylate as the raw material (meth)acrylic acid ester.

[0091] 4. Definitions [1] Water absorbent resin, water absorbent resin powder, water absorbent resin particles, In the present invention, the term "water-absorbent resin" refers to a water-swellable, water-insoluble polymer gelling agent. "Water-swellable" means that the CRC defined by ERT441.2-02 is 5 g / g or more, and "water-insoluble" means that the Ext defined by ERT470.2-02 is 50 wt% or less. The above-mentioned "water-absorbent resin" is preferably a hydrophilic cross-linked polymer obtained by cross-linking polymerizing an unsaturated monomer having a carboxyl group, but the entire amount (100% by weight) does not need to be a cross-linked polymer, and additives and the like can be contained within a range that satisfies the above-mentioned performance (CRC, Ext). Furthermore, the above-mentioned "water-absorbent resin" may refer to "a polymer crosslinked only inside (i.e., a polymer in which the crosslink density inside and on the surface are substantially the same)" or "a polymer crosslinked both inside and on the surface (i.e., a polymer in which the crosslink density on the surface is relatively high compared to the crosslink density inside)". In this specification, for convenience, a polymer crosslinked only inside may be referred to as "water-absorbent resin powder", and a polymer crosslinked both inside and on the surface may be referred to as "water-absorbent resin particles".

[0092] [2] Polyacrylic acid (salt)-based water-absorbing resin The water-absorbent resin obtained by the method for producing a water-absorbent resin of the present invention is a polyacrylic acid (salt)-based water-absorbent resin. In the present invention, the "polyacrylic acid (salt)-based water-absorbent resin" means a water-absorbent resin made from acrylic acid and / or its salt (hereinafter referred to as "acrylic acid (salt)"). In other words, the polyacrylic acid (salt)-based water-absorbent resin is a water-absorbent resin having structural units derived from acrylic acid (salt) in the polymer and having a graft component as an optional component. Specifically, the polyacrylic acid (salt)-based water-absorbing resin is a water-absorbing resin that contains preferably 50 mol % to 100 mol %, more preferably 70 mol % to 100 mol %, even more preferably 90 mol % to 100 mol %, and particularly preferably substantially 100 mol % of acrylic acid (salt) relative to the total monomers involved in the polymerization reaction (excluding the internal crosslinking agent).

[0093] [3] EDANA and ERT "EDANA" is an abbreviation for European Disposables and Nonwovens Associations, and "ERT" is an abbreviation for EDANA Recommended Test Methods. ERT is a European standard (almost a global standard) for methods of measuring physical properties of water-absorbent resins. In the present invention, unless otherwise specified, the physical properties of the water-absorbent resin are measured in accordance with the original ERT (revised in 2002 / publicly known document).

[0094] [3-1] CRC (ERT441.2-02) "CRC" (Centrifuge Retention Capacity) is an abbreviation for Centrifuge Retention Capacity, and means the water absorption capacity of a water-absorbent resin under no pressure. Specifically, 0.2 g of the water-absorbent resin is placed in a nonwoven bag, and then immersed in a large excess of 0.9 wt % sodium chloride aqueous solution for 30 minutes to allow the water-absorbent resin to freely swell, and then the water-absorbent resin is reacted using a centrifuge (250 G), and the water absorption capacity (unit: g / g) is measured.

[0095] [3-2] Absorption under pressure (AAP) (ERT442.2-02) "AAP" is an abbreviation for Absorption Against Pressure, and refers to the water absorption capacity of a water-absorbent resin under pressure. Specifically, it is the water absorption capacity (unit: g / g) after 0.9 g of water-absorbent resin is swelled in a large excess of 0.9 wt % sodium chloride aqueous solution for 1 hour under a load of 2.06 kPa (21 g / cm2, 0.3 psi). ERT442.2-02 uses the term "Asorption Under Pressure," but the meaning is essentially the same. In the present invention, the load condition is changed to 4.83 kPa (49 g / cm2, 0.7 psi) for measurement. Although "AAP" is used in this specification, it is always the water absorption capacity measured under a load of 4.83 kPa.

[0096] [3-3] Soluble content (ERT470.2-02) The term "soluble content" refers to the water-soluble content (amount of water-soluble components) of a water-absorbent resin. Specifically, it refers to the amount of dissolved polymer (unit: wt%) after 1.0 g of water-absorbent resin is placed in 200 ml of a 0.9 wt % sodium chloride aqueous solution and stirred at 500 rpm for 16 hours. The amount of dissolved polymer is measured by pH titration.

[0097] [3-4] Residual Monomer (ERT430.2-02) The residual monomer means an unreacted monomer component remaining in a water absorbent resin. Specifically, the residual monomer is the amount of the residual monomer component extracted after adding 1.0 g of a water absorbent resin to 200 ml of a 0.9 wt % aqueous sodium chloride solution and stirring at 500 rpm for 1 hour, and is measured using high performance liquid chromatography.

[0098] [3-5] Vortex (JIS K7224 (1996)) Vortex is a method for evaluating the absorption rate of a water-absorbent resin. Specifically, 2.0 g of a water-absorbent resin is added to 50 g of a 0.9 mass % sodium chloride aqueous solution stirred at 600 rpm with a stirrer tip, and the time (unit: seconds) until the stirrer tip is covered with the liquid is measured.

[0099] [3-6] Particle size distribution (ERT480.2-02) The particle size distribution means the particle size distribution of a water absorbent resin measured by sieve classification. Specifically, using a set of sieves with a diameter of 200 mm, sieve openings of 850 μm, 600 μm, 300 μm, 150 μm, and 45 μm, and a tray, 100.0 g of a water absorbent resin is classified for 10 minutes with a sieve shaker, and the amount of the water absorbent resin remaining on each sieve mesh and in the tray is measured, and the particle size distribution is calculated (unit: weight %).

[0100] [4] Other In this specification, "X to Y" indicating a range means "greater than or equal to X and less than or equal to Y." Furthermore, the unit of weight, "t (ton)," means "metric ton." Unless otherwise noted, "ppm" means "ppm by weight," and "weight" and "mass," "weight %" and "mass %, "parts by weight" and "parts by mass" are treated as synonyms. Furthermore, "acid (salt)" means "acid and / or its salt," and "(meth)acrylic" means "acrylic and / or methacrylic." [Example]

[0101] The present invention will be described in more detail below with reference to examples and comparative examples. However, the present invention should not be construed as being limited to these examples and comparative examples. Examples obtained by appropriately combining the technical means disclosed in each example are also included within the scope of the present invention. Unless otherwise noted, electrical equipment used in the examples and comparative examples, as well as for measuring the physical properties of the water-absorbing agent, uses a 200V or 100V power supply. Unless otherwise noted, the physical properties of the water-absorbing agent were measured under conditions of room temperature (20°C to 25°C) and a relative humidity of 50±5% RH. For convenience, "liter" may be expressed as "l" or "L," and "weight %" as "wt%" or "%."

[0102] <Gel permeation chromatography analysis conditions> Gel permeation chromatography (GPC) analysis and the like in the following Preparation Examples, Examples, and Comparative Examples were carried out under the following conditions. Columns used: TSKgel G3000PWxl, TSKgel G2500PWxl (Tosoh Corporation), one each Eluent: water / disodium hydrogen phosphate / sodium dihydrogen phosphate = 98 / 1 / 1 (weight ratio) Detector: RI Column temperature: 50℃

[0103] <Amount of polymer produced> The amount of polymer produced was evaluated as follows. A 10-fold volume of 10 wt% NaOH aqueous solution was added to the reaction solution, and hydrolysis was performed to decompose the resulting polymer into only the main chain units of the acrylic acid polymer. The hydrolyzed solution was then diluted 10-fold with an eluent and subjected to GPC analysis using an RI detector. The amount of polymer produced was evaluated using this concentration-corrected RI intensity value. The concentration-corrected RI intensity in the examples was calculated according to the following definition. (Corrected RI intensity) = (RI intensity at GPC retention time ≦ 39 min) / (Dilution concentration at hydrolysis) / (Dilution concentration of GPC carrier)

[0104] Preparation Example 1 Using the apparatus shown in Figure 1, 171 g of a 95 wt% aqueous solution of 3-hydroxypropionic acid and 18 g of potassium hydroxide were added to the reactor. The system was then depressurized to 10 kPa and heated. When the internal temperature reached 140°C, an 80 wt% aqueous solution of 3-hydroxypropionic acid was fed into the reactor at a rate of 120 g / h. Air was also fed into the gas phase of the reactor at a rate of 3 L / h. A mixture of the product and air was extracted from the reactor through a gas extraction tube and condensed and collected in a condenser. After the reaction was continued for 5 hours, 284 g of the reaction liquid was extracted from the reactor and used as the reaction liquid for the test tube polymerization test.

[0105] Examples 1-1 to 1-4, Comparative Examples 1-1 to 1-6 The reaction solution from Preparation Example 1 was placed in a test tube, and various polymerization inhibitors were added. The test tube was then capped with a perforated silicone stopper and placed in a heating device heated to 140°C for 3 hours. The test device is shown in Figure 2. After 3 hours, heating was stopped, and the amount of polymer produced was evaluated by GPC analysis. The results are shown in Table 1.

[0106] [Table 1]

[0107] Example 2-1, Comparative Examples 2-1 and 2-2 The reaction was carried out in the same manner as in Example 1, except that in the test tube polymerization test of Example 1, the reaction temperature was changed to 100°C and the type and concentration of the polymerization inhibitor were changed as shown in Table 2. The results are shown in Table 2.

[0108] [Table 2]

[0109] Examples 3-1 to 3-3, Comparative Example 3-1 The reaction was carried out in the same manner as in Example 1 except that the iron (II) acetate concentration was changed. The results are shown in Table 3.

[0110] [Table 3]

[0111] Reference examples 4-1~4-3 The test tube polymerization test in Example 2 was carried out in the same manner, except that the reaction solution was changed to 2-carboxyethyl acrylate and the type and concentration of the polymerization inhibitor were changed as shown in Table 4. The results are shown in Table 4. The 2-carboxyethyl acrylate contained 900-1100 ppm of methoquinone. The test in an atmospheric environment was carried out in an open system exposed to air.

[0112] [Table 4]

[0113] Example 5, Comparative Example 5 The reaction was carried out in the same manner as in Preparation Example 1, except that the temperature was 200°C, the pressure was 101 kPa, the raw material supply rate was 60 g / min, no catalyst was used, a polymerization inhibitor was added to the initial charge, the operation time was 750 min, and the type and concentration of the polymerization inhibitor were as shown in Table 5. The results are shown in Table 5.

[0114] [Table 5]

[0115] Example 6 In a 3-liter jacketed glass vessel equipped with a distillation column with three perforated trays, 1240 g of a 95 wt% aqueous solution of 3-hydroxypropionic acid (obtained through a purification process from a sugar fermentation broth) and 90 g of potassium hydroxide were added to the reactor. 2.3 g of iron acetate was added to the reactor as a polymerization inhibitor. After reducing the pressure inside the system to 20 kPa, the temperature was raised to 150 °C, and an 85 wt% aqueous solution of 3-hydroxypropionic acid was fed at a rate of 600 g / h. The jacket was heated with heat transfer oil. Air was also fed into the gas phase of the reactor at a rate of 3 L / h. The distillate was condensed in its entirety in a cooling tube, and 300 g / h of the distillation column was recycled as reflux, while 600 g / h was collected as product. The reaction continued for a total of 16 hours, yielding 8.7 kg of aqueous acrylic acid. The reaction solution in the reactor was withdrawn at a rate of 24 g / h, and the withdrawn solution after 12 hours of operation was analyzed by GPC to confirm the amount of polymer produced. The results are shown in Table 6.

[0116] [Table 6]

[0117] Preparation Example 2 The aqueous acrylic acid solution obtained by the method described in Example 6 was supplied to an azeotropic dehydration column, and water and low-boiling impurities were distilled off using toluene as the azeotropic solvent, yielding crude acrylic acid. This crude acrylic acid was supplied to the bottom of a high-boiling impurity separation column having 27 perforated trays with weirs, and distilled at a reflux ratio of 1 to remove high-boiling impurities such as a dimer of acrylic acid (acrylic acid dimer), yielding crude acrylic acid. Hydrazine hydrate was added to the crude acrylic acid as an aldehyde treatment agent, and the mixture was distilled in a simple distillation apparatus to obtain purified acrylic acid.

[0118] Example 7 An aqueous solution was prepared by adding 441.6 parts by weight of the purified acrylic acid obtained in Preparation Example 2, 182.0 parts by weight of a 48.5 wt% aqueous sodium hydroxide solution, 2.4 parts by weight of polyethylene glycol diacrylate (average number of polyethylene glycol units (average n number): 9), 1.35 parts by weight of a 2.0 wt% aqueous solution of trisodium diethylenetriaminepentaacetate, and 352.9 parts by weight of deionized water to a 2 L polypropylene container and mixing them. The deionized water had been preheated to 40°C. Next, while stirring the aqueous solution, 187.0 parts by weight of a 48.5 wt % aqueous sodium hydroxide solution was added to the aqueous solution over a period of about 30 seconds in an open-to-air state, and mixed to prepare an aqueous monomer solution. Note that the temperature of the aqueous monomer solution rose to about 80°C due to the heat of neutralization and heat of dissolution generated during the mixing process. Thereafter, when the temperature of the aqueous monomer solution reached 78°C, 32.71 parts by weight of a 2.6 wt % aqueous solution of sodium persulfate was added as a polymerization initiator, and the mixture was stirred for about 5 seconds to obtain a reaction liquid. Next, the reaction solution was poured into a stainless steel bat-shaped container in an open-air state. The bat-shaped container had a bottom size of 200 mm x 260 mm, an upper size of 460 mm x 560 mm, and a height of 140 mm, and the cross section of the center was trapezoidal, with a silicone sheet attached to the inner surface. Furthermore, before pouring the reaction solution into the bat-shaped container, it was placed on a hot plate heated to 50°C to preheat it. After the reaction liquid was poured into the bat-shaped container, the polymerization reaction started within 1 minute. The reaction liquid expanded and foamed upward while generating steam, and then contracted to a size slightly larger than the bottom of the bat-shaped container. The polymerization reaction (expansion and contraction) was completed within about 1 minute. A hydrogel-like cross-linked polymer (hereinafter referred to as "hydrogel") was obtained through the polymerization reaction. Next, the hydrogel was cut into pieces of an appropriate size, and then fed into a screw extruder to crush the gel, thereby obtaining a particulate hydrogel having a particle size of 0.1 to 2 mm. Next, the particulate hydrogel was spread on a wire mesh with an opening of 300 μm (50 mesh) and placed in a hot air dryer. Thereafter, the particulate hydrogel was dried by passing hot air at 190° C. for 30 minutes to obtain a dried polymer. Subsequently, the dried polymer was put into a roll mill and pulverized, and then classified using two types of JIS standard sieves with openings of 710 μm and 150 μm to obtain an irregularly pulverized water absorbent resin powder (1). Next, 3.9 parts by weight of a surface cross-linking agent solution (1) consisting of 0.4 parts by weight of ethylene carbonate, 0.7 parts by weight of propylene glycol, and 2.8 parts by weight of deionized water was added to 100 parts by weight of the water absorbent resin powder (1) and mixed until uniform, thereby obtaining a humidified mixture (1). Subsequently, the humidified mixture (1) was heat-treated at 200°C for 40 minutes, cooled to 60°C, and passed through a sieve with a mesh size of 710 μm. Particles that did not pass through the 710 μm mesh were crushed by lightly pressing them on a mesh with a spatula and passed through, and particles that were not completely crushed were removed. In this way, surface-cross-linked water absorbent resin particles (1) in an irregular crushed shape were obtained. Tables 7 and 8 show the physical properties of the water absorbent resin powder (1) and the water absorbent resin particles (1).

[0119] [Table 7]

[0120] [Table 8]

[0121] Example 8 A separable glass flask equipped with a thermometer, reflux condenser, and stirrer was charged with 33.0 g of the purified acrylic acid obtained in Preparation Example 2, 0.33 g of pentaerythritol triallyl ether neoallyl (trade name "Neoallyl P-30M" manufactured by Osaka Soda Co., Ltd.), 0.95 g of potassium carbonate, 43.4 g of ethyl acetate, and 173.6 g of cyclohexane, and the mixture was heated to 63°C with stirring. Nitrogen gas was passed through the reactor for 30 minutes while stirring. Then, an initiator solution containing 0.355 g of 2,2'-azobis(2,4-dimethylvaleronitrile), 10.0 g of ethyl acetate, and 40.0 g of cyclohexane was added dropwise from a dropping nozzle over 1 hour and 45 minutes to the polymerization reaction system, which was maintained at a constant temperature of 63°C. After the entire addition was completed, the reaction solution was heated to 70°C and aged for 4 hours and 15 minutes to complete the polymerization (precipitation polymerization). Subsequently, the reaction solution was filtered to recover the polymer precipitate, which was then dried under reduced pressure at 105°C for 5 hours and 30 minutes to obtain cosmetic additive (1). The concentration of the obtained cosmetic additive (1) was adjusted to 0.5 wt %, and the measurement aqueous solution was adjusted with a 50 wt % aqueous sodium hydroxide solution to a pH of 7.3 to 7.8. A B-type viscometer (TVB-10, rotor No. M4, manufactured by Toki Sangyo Co., Ltd.) was used to measure viscosity, and the measurement was carried out at 25°C and a rotation speed of 4 rpm. The viscosity of the obtained cosmetic additive was 123.3 Pa s. The obtained cosmetic additive (1) was mixed with the various components shown in Table 9 to prepare a moisturizing gel with a pH adjusted to 5.8 to 6.0. In addition to cosmetic additives, the moisturizing gel was prepared using 1,3-butylene glycol (Daicel Corporation), glycerin (Miyoshi Oil & Fat Co., Ltd.), EDTA-2Na (Chubu Cherest Co., Ltd.), potassium hydroxide (Fujifilm Wako Pure Chemical Industries, Ltd.), sodium hyaluronate (Kewpie Corporation), and phenoxyethanol (Yokkaichi Chemical Co., Ltd.).

[0122] [Table 9]

[0123] The obtained moisturizing gel was filled into a UV quartz glass cell (optical path length 10 mm, optical path width 10 mm, completely transparent for fluorescence, capacity 3.5 ml) and subjected to a visual evaluation of transparency, which was found to be transparent with no turbidity. Furthermore, a sensory evaluation was carried out to assess the feel of the resulting moisturizing gel after use, and it was found to have a very refreshing feel. Furthermore, when the moisturizing gel was applied to the upper arm and a sensory evaluation was conducted to check for stickiness from when it first blended into the skin until immediately after it had been blended, no stickiness was felt at all.

[0124] The cosmetic additive obtained by the manufacturing method of the present invention can be used in various cosmetics other than the moisturizing gel. Formulation examples other than the moisturizing gel using the cosmetic additive (1) of Example 8 are shown as reference cosmetics in Table 10, but the cosmetics using the cosmetic additive of the present invention are not limited to these. The pH of the reference cosmetic prepared using the cosmetic additive (1) of Example 8 according to the formulation in Table 10 was measured at 25°C using a glass electrode pH meter (model: LAQUA F-72, manufactured by Horiba, Ltd.), and the viscosity was measured using a TVB-10 viscometer (manufactured by Toki Sangyo Co., Ltd.) with a rotor No. 4 at 12 rpm for 1 minute. The results are shown in Table 10. The components listed in Table 10 are as follows. 1,3-Butylene glycol: 1,3-butylene glycol (UK) (manufactured by Daicel Corporation), glycerin: concentrated glycerin for cosmetics (manufactured by Miyoshi Oil & Fat Co., Ltd.), xanthan gum: Echo Gum T (manufactured by CP Kelco US, Inc.), (Acrylates / C10-30 alkyl acrylate) crosspolymer: Carbopol ETD2020 (manufactured by Lubrizol Corporation), sodium hydroxide: sodium hydroxide (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), phospholipids, others: LiNPOSOME-V-MC (manufactured by Lilac Pharma Co., Ltd.), phenoxyethanol: phenoxyethanol-S (manufactured by Yokkaichi Chemical Co., Ltd.)

[0125] [Table 10]

[0126] Example 9 The purified acrylic acid obtained in Preparation Example 2 was used to carry out an esterification reaction with n-butanol (petroleum-derived). Specifically, 50 g of acrylic acid, 75 g of n-butanol (petroleum-derived), 1 g of p-toluenesulfonic acid, and 0.2 g of hydroquinone were charged into a 300 ml round-bottom flask, and the mixture was heated to 80°C for 5 hours to carry out the esterification step. After the reaction, the reaction solution was analyzed by gas chromatography, and it was confirmed that the amounts of acrylic acid and n-butanol had decreased and that n-butyl acrylate had been produced.

[0127] Example 10 The purified acrylic acid obtained in Preparation Example 2 was used to carry out an esterification reaction with n-butanol (biomass-derived). That is, the esterification step was carried out in the same manner as in Example 9, except that n-butanol (biomass-derived) was used instead of n-butanol (petroleum-derived). After the reaction, the reaction solution was analyzed by gas chromatography, and it was confirmed that acrylic acid and n-butanol had decreased, and that n-butyl acrylate had been produced.

[0128] Example 11 The purified acrylic acid obtained in Preparation Example 2 was used to carry out an esterification reaction with 2-ethylhexanol. That is, the esterification step was carried out in the same manner as in Example 9, except that 120 g of 2-ethylhexanol (petroleum-derived) was used instead of 75 g of n-butanol (petroleum-derived). After the reaction, the reaction solution was analyzed by gas chromatography, and it was found that the amounts of acrylic acid and 2-ethylhexanol had decreased, confirming the production of 2-ethylhexyl acrylate.

Claims

1. A method for producing (meth)acrylic acid, comprising a reaction step of obtaining (meth)acrylic acid from a raw material containing a 3-hydroxycarboxylic acid and / or a condensate thereof, In the production method, the reaction step is carried out under conditions in which an iron-based compound is present in a reaction liquid containing a 3-hydroxycarboxylic acid and / or a condensate thereof and (meth)acrylic acid. A method for producing (meth)acrylic acid, comprising:

2. 2. The method for producing (meth)acrylic acid according to claim 1, wherein the reaction step is carried out at a temperature of 100 to 300°C.

3. 3. The method for producing (meth)acrylic acid according to claim 1, wherein the concentration of the iron-based compound in the reaction solution is 1 to 30,000 ppm.

4. A method for producing a hydrophilic resin using a raw material containing a 3-hydroxycarboxylic acid and / or a condensate thereof, comprising: The production method includes a reaction step of producing (meth)acrylic acid from a 3-hydroxycarboxylic acid and / or a condensate thereof in the presence of an iron-based compound in a reaction liquid containing a 3-hydroxycarboxylic acid and / or a condensate thereof and (meth)acrylic acid; a polymerization step of polymerizing the monomer component containing (meth)acrylic acid obtained in the reaction step to produce a hydrophilic resin, A method for producing a hydrophilic resin, wherein the main product obtained in the reaction step is (meth)acrylic acid.

5. 5. The method for producing a hydrophilic resin according to claim 4, wherein the hydrophilic resin is a water-absorbent resin.

6. 5. The method for producing a hydrophilic resin according to claim 4, wherein the hydrophilic resin is a cosmetic additive.

7. A method for producing a (meth)acrylic acid ester using a raw material containing a 3-hydroxycarboxylic acid and / or a condensate thereof, comprising: The production method includes a reaction step of producing (meth)acrylic acid from a 3-hydroxycarboxylic acid and / or a condensate thereof in the presence of an iron-based compound in a reaction liquid containing a 3-hydroxycarboxylic acid and / or a condensate thereof and (meth)acrylic acid; an esterification step in which the component containing (meth)acrylic acid obtained in the reaction step is reacted with an alcohol or an epoxide to produce an ester, A method for producing a (meth)acrylic acid ester, characterized in that the main product among the products obtained in the reaction step is (meth)acrylic acid.

8. The (meth)acrylic acid ester may be methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, 1-octyl (meth)acrylate, 2-octyl (meth)acrylate, isononyl (meth)acrylate, isobornyl (meth)acrylate, isoamyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, lauryl (meth)acrylate, or p) The method for producing a (meth)acrylic acid ester according to claim 7, wherein the (meth)acrylic acid ester is any one of stearyl acrylate, cyclohexyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate, or an ester of 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, trimethylolpropane, pentaerythritol, glycerin, polyethylene glycol, and polypropylene glycol in which some or all of a plurality of alcohol groups are esterified with (meth)acrylic acid.

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