Adsorbent and method for removing impurities

Abstract

To provide an absorbent capable of efficiently removing impurities represented by aldehyde or organic acids in a non water-soluble organic compound represented by fat, and also to provide a method for efficiently removing impurities represented by aldehyde or organic acids in a non water-soluble organic compound represented by fat.SOLUTION: An absorbent is for removing impurities in a non water-soluble organic compound, the absorbent having a primary amino group. A removal method of impurities uses the absorbent to remove impurities in a non water-soluble organic compound.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an adsorbent and a method for removing impurities using the adsorbent. [Background technology]

[0002] Vegetable oils such as olive oil, soybean oil, palm oil, etc. are widely used for food. Olive oil, in particular, contains a large amount of oleic acid, a monounsaturated fatty acid that reduces LDL and maintains HDL, and also contains moderate amounts of linoleic acid and α-linolenic acid, which are essential polyunsaturated fatty acids that cannot be produced in the human body. As a result, olive oil is listed as a component of the "Mediterranean diet," and demand for it is expected to increase.

[0003] On the other hand, in order to meet the growing demand, it is important not only to increase olive oil production but also to utilize olive pomace oil extracted from olive oil residue. Olive pomace oil is produced through solvent extraction from olive oil residue followed by neutralization, dewaxing, bleaching, deodorization, etc., but its quality is considered inferior to virgin olive oil, refined olive oil, and olive oil. For this reason, its main use is in the food industry, such as in fried foods, simmered dishes, sauces, and confectioneries. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-118781 [Non-patent literature]

[0005] [Non-Patent Document 1] J.Agric.Food Chem.,Vol.68,p5927(2020). [Non-patent document 2] Food Research Institute Research Report, No. 76, p. 51 (2012). [Non-patent document 3] Oil Chemistry, Vol.26, p150(1977). Summary of the Invention [Problem to be solved by the invention]

[0006] As disclosed in Non-Patent Document 1, factors that affect the quality of olive oil include the presence of aldehydes and organic acids. If aldehydes and organic acids can be sufficiently removed during the olive pomace oil production process, the added value of olive pomace oil can be increased, such as by improving its quality and expanding its range of uses.

[0007] Furthermore, when fats and oils are used for deep frying, aldehydes and organic acids are produced due to deterioration with continued use, resulting in a decrease in quality, as disclosed in Non-Patent Documents 2 and 3. Therefore, if there were a method that not only inhibits the production of aldehydes and organic acids but also efficiently removes them when they are produced, it would be possible to extend the period of continuous use, which would be economically beneficial.

[0008] One possible method for removing aldehydes is the method using an anion exchange resin disclosed in Patent Document 1. However, since the method for removing aldehydes disclosed in Patent Document 1 is a method for removing aldehydes from an aqueous solution, it was unclear whether it could be applied to removing aldehydes from oils and fats.

[0009] The present invention has been made in view of the above problems, and an object of the present invention is to provide an adsorbent that efficiently removes impurities, such as aldehydes and organic acids, from water-insoluble organic compounds, such as fats and oils. Another object of the present invention is to provide a method for efficiently removing impurities, such as aldehydes and organic acids, from water-insoluble organic compounds, such as fats and oils. [Means for solving the problem]

[0010] As a result of extensive research, the present inventors have discovered that adsorbents having primary amino groups exhibit excellent adsorption properties for impurities, such as aldehydes and organic acids, in water-insoluble organic compounds, such as fats and oils, and have arrived at the present invention.

[0011] That is, the gist of the present invention is as follows. [1] An adsorbent for removing impurities in water-insoluble organic compounds, the adsorbent having a primary amino group. [2] The adsorbent according to [1], wherein the impurities include aldehydes. [3] The adsorbent according to [2], wherein the impurities further include organic acids. [4] The adsorbent according to any one of [1] to [3], wherein the water-insoluble organic compound comprises an oil or fat. [5] The adsorbent according to any one of [1] to [4], which contains at least one selected from the group consisting of resin, polysaccharide, silica, and glass. [6] The adsorbent according to [5], which contains a resin. [7] The adsorbent according to [6], wherein the resin comprises at least one selected from the group consisting of an acrylic resin, a styrene resin, a polyvinylamine resin, a triallyl isocyanurate resin, and a vinyl ether resin. [8] The adsorbent according to [6] or [7], wherein the resin has a crosslinked structure. [9] The adsorbent according to [7] or [8], wherein the acrylic resin contains an epoxy group-containing (meth)acrylate unit and a crosslinkable (meth)acrylate unit.

[10] The adsorbent according to [7] or [8], wherein the styrene-based resin contains an aromatic monovinyl monomer unit and a crosslinkable aromatic vinyl monomer unit.

[11] The adsorbent according to [7] or [8], wherein the polyvinylamine resin contains an N-vinylcarboxylic acid amide unit.

[12] The adsorbent according to any one of [1] to

[11] , wherein the primary amino group is introduced by at least one selected from the group consisting of polyalkylene polyamine, polyvinyl amine, and polyallyl amine.

[13] The adsorbent according to any one of [1] to

[12] , which has porosity.

[14] The adsorbent according to

[13] , wherein the pore diameter is 1 nm to 1000 nm.

[15] A method for removing impurities, comprising removing impurities from a water-insoluble organic compound using the adsorbent according to any one of [1] to

[14] . [Effects of the Invention]

[0012] The adsorbent of the present invention can efficiently remove impurities, such as aldehydes and organic acids, from water-insoluble organic compounds, such as fats and oils. Furthermore, the method for removing impurities of the present invention can efficiently remove impurities such as aldehydes and organic acids from water-insoluble organic compounds such as fats and oils. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a diagram showing a high performance liquid chromatogram of the aldehyde-containing oil or fat after treatment with the adsorbent obtained in Example 1. [Figure 2] FIG. 2 is a diagram showing a high performance liquid chromatogram of the aldehyde-containing oil or fat after treatment with the adsorbent obtained in Example 2. [Figure 3] FIG. 1 is a diagram showing a high performance liquid chromatogram of an aldehyde-containing oil or fat. DETAILED DESCRIPTION OF THE INVENTION

[0014] The present invention will be described in detail below, but the present invention is not limited to the following embodiments and can be practiced with various modifications within the scope of the gist. In this specification, when the expression "to" is used, it is used as an expression including the numerical values or physical property values before and after it. In addition, in this specification, "(meth)acrylic" refers to "acrylic", "methacrylic", or both, and "(meth)acrylate" refers to "acrylate", "methacrylate", or both.

[0015] (adsorbent) The adsorbent of the present invention is intended to remove impurities from water-insoluble organic compounds.

[0016] In this specification, the term "water-insoluble organic compound" refers to a compound that is not freely miscible with water in a liquid state, and examples thereof include compounds classified as water-insoluble liquids in Class 4 of the Fire Service Act, fats and oils, etc. Among these water-insoluble organic compounds, propylene glycol methyl ether acetate, propylene glycol monomethyl ether, ethyl acetate, butyl acetate, methyl isobutyl carbinol, cyclohexanone, and fats and oils are preferred, with fats and oils being more preferred, for applications in the electronics industry, which requires high purity, and the food industry, which requires high added value.

[0017] The impurities to be removed by the adsorbent of the present invention preferably contain aldehydes, and more preferably contain aldehydes and organic acids, since the adsorbent of the present invention has excellent adsorption properties.

[0018] The adsorbent of the present invention has a primary amino group.

[0019] Examples of materials constituting the adsorbent include resins, polysaccharides, silica, glass, etc. Among these materials constituting the adsorbent, resins, polysaccharides, silica, and glass are preferred because they have excellent mechanical strength and chemical durability, and resins are more preferred.

[0020] Examples of the resin constituting the adsorbent include acrylic resins, styrene resins, polyvinylamine resins, triallyl isocyanurate resins, vinyl ether resins, etc. Among these resin types, acrylic resins, styrene resins, polyvinylamine resins, triallyl isocyanurate resins, and vinyl ether resins are preferred because they have excellent mechanical strength and chemical durability, and acrylic resins, styrene resins, and polyvinylamine resins are more preferred because they can easily impart porosity to the adsorbent and have excellent chemical durability against acids and alkalis, with acrylic resins and polyvinylamine resins being even more preferred.

[0021] In this specification, the acrylic resin refers to a resin in which structural units derived from (meth)acrylate account for 50% by mass or more of the total monomer units constituting the acrylic resin (100% by mass), and this proportion is preferably 80% by mass or more. The acrylic resin may contain structural units other than those derived from (meth)acrylate.

[0022] Examples of (meth)acrylates include alkyl (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, stearyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and cyclohexyl (meth)acrylate; hydroxyl group-containing (meth)acrylates such as hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, and glycerin mono(meth)acrylate; and epoxy group-containing (meth)acrylates such as glycidyl (meth)acrylate, 4,5-epoxybutyl (meth)acrylate, and 9,10-epoxystearyl (meth)acrylate. Examples of the (meth)acrylate include (meth)acrylamides such as (meth)acrylamide, dimethyl(meth)acrylamide, and hydroxyethyl(meth)acrylamide; cyano group-containing (meth)acrylates such as (meth)acrylonitrile; alkylene di(meth)acrylates such as ethylene glycol di(meth)acrylate; polyalkylene glycol di(meth)acrylates such as polyethylene glycol di(meth)acrylate; and crosslinkable (meth)acrylates such as N,N'-alkylene bis(meth)acrylamide, glycerol di(meth)acrylate, and trimethylolpropane tri(meth)acrylate. These (meth)acrylates may be used alone or in combination of two or more. Among these (meth)acrylates, it is preferable to include an epoxy group-containing (meth)acrylate and a crosslinkable (meth)acrylate, more preferably to include glycidyl (meth)acrylate and alkylene glycol di(meth)acrylate, and even more preferably to include glycidyl (meth)acrylate and ethylene glycol di(meth)acrylate, because primary amino groups can be easily introduced into them and they have excellent resistance to dissolution in water-insoluble organic compounds such as fats and oils.

[0023] When the acrylic resin contains epoxy group-containing (meth)acrylate units and crosslinkable (meth)acrylate units, the content of the epoxy group-containing (meth)acrylate units in the acrylic resin is preferably 5% to 95% by mass, more preferably 10% to 90% by mass, based on 100% by mass of the acrylic resin. When the content of the epoxy group-containing (meth)acrylate units is 5% by mass or more, the primary amino group introduction efficiency is excellent. Furthermore, when the content of the epoxy group-containing (meth)acrylate units is 95% by mass or less, the mechanical strength is excellent.

[0024] When the acrylic resin contains an epoxy group-containing (meth)acrylate unit and a crosslinkable (meth)acrylate unit, the content of the crosslinkable (meth)acrylate unit in the acrylic resin is preferably 5% by mass to 95% by mass, and more preferably 10% by mass to 90% by mass, based on 100% by mass of the acrylic resin. When the content of the crosslinkable (meth)acrylate unit is 5% by mass or more, the mechanical strength is excellent. Furthermore, when the content of the crosslinkable (meth)acrylate unit is 95% by mass or less, the introductory ability of a primary amino group is excellent.

[0025] In this specification, a styrene-based resin refers to a resin in which structural units derived from aromatic vinyl monomers account for 50% by mass or more of 100% by mass of all monomer units constituting the styrene-based resin, and this proportion is preferably 80% by mass or more. The styrene-based resin may contain structural units other than those derived from aromatic vinyl monomers.

[0026] Examples of aromatic vinyl monomers include aromatic monovinyl monomers such as styrene, methylstyrene, ethylstyrene, α-methylstyrene, chlorostyrene, chloromethylstyrene, and bromobutylstyrene; and crosslinkable aromatic vinyl monomers such as divinylbenzene, bis(vinylphenyl)ethane, divinylnaphthalene, and 2,4,6-trivinylethylbenzene. These aromatic vinyl monomers may be used alone or in combination of two or more. Among these aromatic vinyl monomers, aromatic monovinyl monomers and crosslinkable aromatic vinyl monomers are preferred because they have excellent resistance to dissolution in water-insoluble organic compounds such as oils and fats, and styrene and divinylbenzene are more preferred.

[0027] When the styrene-based resin contains an aromatic monovinyl monomer unit and a crosslinkable aromatic vinyl monomer unit, the content of the aromatic monovinyl monomer unit in the styrene-based resin is preferably 5% by mass to 98% by mass, more preferably 10% by mass to 96% by mass, based on 100% by mass of the styrene-based resin. When the content of the aromatic monovinyl monomer unit is 2% by mass or more, the introduction efficiency of primary amino groups is excellent. Furthermore, when the content of the aromatic monovinyl monomer unit is 98% by mass or less, the mechanical strength is excellent.

[0028] When the styrene-based resin contains an aromatic monovinyl monomer unit and a crosslinkable aromatic vinyl monomer unit, the content of the crosslinkable aromatic vinyl monomer unit in the styrene-based resin is preferably 2% by mass to 95% by mass, more preferably 4% by mass to 90% by mass, based on 100% by mass of the styrene-based resin. When the content of the crosslinkable aromatic vinyl monomer unit is 2% by mass or more, the mechanical strength is excellent. Furthermore, when the content of the crosslinkable aromatic vinyl monomer unit is 95% by mass or less, the introduction efficiency of a primary amino group is excellent.

[0029] In this specification, the polyvinylamine resin refers to a resin in which, out of 100% by mass of all monomer units constituting the polyvinylamine resin, structural units derived from N-vinylcarboxylic acid amide account for 50% by mass or more, and this proportion is preferably 80% by mass or more. The polyvinylamine resin may contain structural units other than those derived from N-vinylcarboxylic acid amide.

[0030] Examples of N-vinylcarboxylic acid amides include N-vinylformamide, N-methyl-N-vinylformamide, N-vinylacetamide, N-methyl-N-vinylacetamide, N-vinylpropionamide, N-methyl-N-vinylpropionamide, N-vinylbutylamide, and N-vinylisobutylamide. These N-vinylcarboxylic acid amides may be used alone or in combination of two or more. Among these N-vinylcarboxylic acid amides, N-vinylformamide and N-vinylacetamide are preferred, with N-vinylformamide being more preferred, due to their excellent atom efficiency and ease of availability and synthesis.

[0031] In this specification, the triallyl isocyanurate resin is a resin synthesized using triallyl isocyanurate as a crosslinking agent, and refers to a resin in which constitutional units derived from triallyl isocyanurate account for 10% by mass or more of 100% by mass of all monomer units constituting the triallyl isocyanurate resin, and this proportion is preferably 20% by mass or more. The triallyl isocyanurate resin may contain constitutional units other than those derived from triallyl isocyanurate.

[0032] In this specification, the vinyl ether resin refers to a resin in which, out of 100% by mass of all monomer units constituting the vinyl ether resin, vinyl ether-derived structural units account for 50% by mass or more, and this proportion is preferably 80% by mass or more. The vinyl ether resin may also contain structural units other than those derived from vinyl ether.

[0033] Examples of vinyl ethers include monovinyl ethers such as methyl vinyl ether, ethyl vinyl ether, butyl vinyl ether, hydroxyethyl vinyl ether, and chloroethyl vinyl ether; and divinyl ethers such as ethylene glycol divinyl ether, diethylene glycol divinyl ether, and triethylene glycol divinyl ether. These vinyl ethers may be used alone or in combination of two or more. Among these vinyl ethers, it is preferable to include monovinyl ethers and divinyl ethers because they have excellent resistance to dissolution in water-insoluble organic compounds such as oils and fats.

[0034] The resin constituting the adsorbent preferably has a crosslinked structure, since this resin has excellent resistance to dissolution by water-insoluble organic compounds such as oils and fats.

[0035] Examples of methods for introducing a crosslinked structure include a method of polymerizing a monomer containing a crosslinkable monomer, a method of reacting a crosslinking agent after obtaining a polymer, etc. Among these methods for introducing a crosslinked structure, the method of polymerizing a monomer containing a crosslinkable monomer is preferred because it has excellent production stability.

[0036] The content of the crosslinkable monomer is preferably 2% by mass to 95% by mass, and more preferably 3% by mass to 90% by mass, based on 100% by mass of all monomers used in producing the resin. When the content of the crosslinkable monomer is 2% by mass or more, the resin has excellent mechanical strength and is easily made porous. When the content of the crosslinkable monomer is 95% by mass or less, the reaction of introducing primary amino groups is easily carried out.

[0037] Examples of polysaccharides constituting the adsorbent include agarose, cellulose, dextran, chitin, chitosan, etc. Among these polysaccharides, chitin having a starting point for introducing a primary amino group and chitosan having a primary amino group are preferred.

[0038] Silica and glass preferably contain an organosilicon compound having a reactive functional group, such as 3-glycidoxypropyltrimethoxysilane, as a raw material, since a reactive functional group, which will be described later, can be introduced into the adsorbent.

[0039] (primary amino group) The adsorbent of the present invention has a primary amino group. The adsorbent of the present invention may have a functional group other than a primary amino group, such as a secondary amino group, a tertiary amino group, or a quaternary ammonium group.

[0040] The primary amino group is preferably immobilized by a covalent bond, since this provides an adsorbent with excellent durability. Examples of methods for immobilizing a primary amino group by a covalent bond include a method in which a monomer containing a monomer that generates a primary amino group in a post-reaction is polymerized, followed by generation of a primary amino group in a post-reaction, and a method in which a monomer containing a monomer having a reactive functional group is polymerized, followed by reaction with a compound having a primary amino group. Among these methods for immobilizing a primary amino group by a covalent bond, the method described above is preferred because it is suitable for industrial production. (1) A method in which a monomer containing a monomer having a reactive functional group is polymerized and then reacted with a compound having a primary amino group (hereinafter sometimes referred to as "method (1)"). (2) A method in which a primary amino group is generated by a post-reaction after polymerizing a monomer containing a monomer that generates a primary amino group by a post-reaction (hereinafter, sometimes referred to as "method (2)") is preferred.

[0041] <Method (1)> Examples of the reactive functional group of the monomer having a reactive functional group used in method (1) include a hydroxyl group, an amino group, a carboxyl group, a halogen group, and an epoxy group. These reactive functional groups may be used alone or in combination of two or more. Among these reactive functional groups, halogen groups and epoxy groups are preferred because they are easy to introduce and have excellent reactivity with compounds having a primary amino group.

[0042] The reactive functional group may be introduced by polymerizing a monomer containing a monomer having a reactive functional group, or the reactive functional group may be introduced after constructing the polymer. Examples of a method for introducing a reactive functional group after constructing a polymer include a method in which a compound (spacer) having a reactive functional group and a monomer including a monomer having a functional group capable of reacting with the compound (spacer) having a reactive functional group are polymerized to construct a polymer, and the polymer is then reacted with the compound (spacer) having a reactive functional group.

[0043] Examples of monomers having a reactive functional group include halogen-containing monomers such as chloromethylstyrene and bromobutylstyrene; and epoxy-containing monomers such as glycidyl (meth)acrylate, allyl glycidyl ether, vinyl glycidyl ether, and 4-epoxy-1-butene. These monomers having a reactive functional group may be used alone or in combination of two or more. Among these monomers having a reactive functional group, halogen-containing monomers and epoxy-containing monomers are preferred because they facilitate the introduction of a compound having a primary amino group. Chloromethylstyrene, bromobutylstyrene, and glycidyl (meth)acrylate are more preferred, and chloromethylstyrene and glycidyl methacrylate are even more preferred.

[0044] The method of polymerizing a monomer including a monomer having a reactive functional group and then reacting it with a compound having a primary amino group is excellent in reactivity, and therefore a method of supplying the compound having a primary amino group as it is or a solution of the compound having a primary amino group dissolved in an organic solvent or water to a polymer having a reactive functional group and causing a covalent bond reaction is preferred.

[0045] Examples of compounds having a primary amino group for introducing a primary amino group include alkylamines, anilines, benzylamines, ethylenediamines, polyalkylenepolyamines such as diethylenetriamine, triethylenetetramine, tetraethylenepentamine, and polyethyleneimine, polyvinylamines, and polyallylamines. These compounds having a primary amino group may be used alone or in combination of two or more. Among these compounds having a primary amino group, polyalkylenepolyamines, polyvinylamines, and polyallylamines are preferred because they can efficiently introduce a primary amino group, and polyethyleneimine and polyvinylamine are more preferred.

[0046] The organic solvent is not particularly limited as long as it can dissolve the compound having a primary amino group. Examples include alcohols such as methanol, ethanol, propyl alcohol, and butanol; ethers such as ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, diethyl ether, cyclopentyl methyl ether, 4-methyltetrahydropyran, tetrahydrofuran (THF), and dioxane; and amides such as dimethylformamide and dimethylacetamide. These organic solvents may be used alone or in combination of two or more. Among these organic solvents, when the adsorbent is a resin, ethers are preferred because they swell the resin and improve the reactivity between the reactive functional group and the compound having a primary amino group. Ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, diethyl ether, cyclopentyl methyl ether, 4-methyltetrahydropyran, tetrahydrofuran, and dioxane are more preferred.

[0047] The reaction temperature for the covalent bonding reaction between the polymer having a reactive functional group and the compound having a primary amino group is preferably 10°C to 120°C, more preferably 20°C to 100°C. When the reaction temperature is 10°C or higher, the covalent bonding reaction can be completed in a short time. Furthermore, when the adsorbent is a resin, decomposition can be suppressed when the reaction temperature is 120°C or lower.

[0048] After the covalent bonding reaction, it is preferred to deactivate any reactive functional groups remaining on the polymer. If the reactive functional groups are left without being deactivated, they may react with the active groups present in the water-insoluble organic compounds during adsorption, resulting in the generation of impurities other than the water-insoluble organic compounds or a decrease in the amount of adsorbed impurities such as aldehydes and organic acids.

[0049] When a reactive functional group, for example, an epoxy group, is deactivated, a method of deactivating the group by reacting it with water in the presence of a catalyst is preferred because it is safer and more economical.

[0050] Examples of catalysts used in inactivating epoxy groups by reacting them with water include aqueous solutions of inorganic acids such as phosphoric acid and sulfuric acid; aqueous solutions of alkalis such as sodium hydroxide and potassium hydroxide; and aqueous solutions of organic acids such as formic acid. These may be used alone or in combination of two or more. Among these catalysts, sulfuric acid is preferred because of its excellent reactivity.

[0051] The concentration of the catalyst used when inactivating the epoxy groups by reacting them with water is preferably 1% by mass to 50% by mass, and more preferably 3% by mass to 30% by mass, in 100% by mass of the aqueous solution, because this can suppress side reactions.

[0052] The reaction temperature when the epoxy group is inactivated by reacting it with water is preferably 10°C to 90°C, more preferably 20°C to 80°C, as this provides excellent reactivity.

[0053] The reaction time when the epoxy group is inactivated by reacting it with water is preferably 0.1 to 24 hours, more preferably 1 to 10 hours, since side reactions can be suppressed.

[0054] When an acid is used to deactivate the reactive functional groups, the primary amino groups are regenerated using an alkali by contacting the deactivated adsorbent with an alkaline aqueous solution of 0.01 mol / L to 5 mol / L.

[0055] <Method (2)> The method of polymerizing a monomer containing a monomer that generates a primary amino group in a post-reaction and then generating a primary amino group in a post-reaction is preferable because it has excellent industrial productivity.

[0056] Examples of monomers that generate a primary amino group in a post-reaction include N-vinylformamide, N-methyl-N-vinylformamide, N-vinylacetamide, N-methyl-N-vinylacetamide, N-vinylpropionamide, N-methyl-N-vinylpropionamide, N-vinylbutylamide, and N-vinylisobutylamide. These N-vinylcarboxylic acid amides may be used alone or in combination of two or more. Among these N-vinylcarboxylic acid amides, N-vinylformamide and N-vinylacetamide are preferred, with N-vinylformamide being more preferred, due to their excellent atom efficiency and ease of availability and synthesis.

[0057] A preferred method of hydrolysis is to add an aqueous alkali solution to a polymer of a monomer containing N-vinylcarboxylic acid amide and heat the mixture while stirring.

[0058] The alkali for the alkaline aqueous solution may be sodium hydroxide, potassium hydroxide, lithium hydroxide, or the like. These alkalis may be used alone or in combination of two or more. Among these alkalis, sodium hydroxide is preferred because of its availability, economy, and ease of post-treatment.

[0059] The alkali concentration of the alkaline aqueous solution is preferably 1% by mass to 50% by mass, and more preferably 3% by mass to 30% by mass, based on 100% by mass of the aqueous solution, in order to suppress side reactions.

[0060] The reaction temperature during the hydrolysis reaction is preferably 50°C to 100°C, more preferably 80°C to 95°C, as this provides excellent reactivity.

[0061] The reaction time during hydrolysis is preferably 0.1 to 24 hours, more preferably 1 to 10 hours, since side reactions can be suppressed.

[0062] The shape of the adsorbent may be spherical or amorphous, but a spherical shape is preferred because it can suppress pressure loss when the adsorbent is packed into a column and a liquid is passed through it, increase the liquid passing rate, and provide excellent productivity in the adsorption process.

[0063] (Physical properties of adsorbent) The volume average particle diameter of the adsorbent of the present invention is preferably 1 μm to 1000 μm, more preferably 4 μm to 700 μm, and even more preferably 10 μm to 500 μm. When the volume average particle diameter of the adsorbent is 1 μm or more, pressure loss when the adsorbent is packed into a column and a liquid is passed through the column can be suppressed, the liquid passing rate can be increased, and the productivity of the adsorption process can be excellent. Furthermore, when the volume average particle diameter of the adsorbent is 1000 μm or less, the column efficiency can be excellent, and the adsorption amount and separation performance can be excellent. In this specification, the volume average particle size of the adsorbent is determined by measuring the particle sizes of 100 randomly selected particles of the adsorbent using an optical microscope, and calculating the volume median size from the distribution.

[0064] When the adsorbent is a resin, the volume average particle diameter of the adsorbent can be adjusted by setting the polymerization conditions for suspension polymerization or emulsion polymerization, specifically, the type and amount of monomer, the type and amount of dispersion stabilizer and emulsifier, the stirring rotation speed, etc. After completion of polymerization, the adsorbent may be classified using a sieve, water sieve, air sieve, or other method to make the volume average particle diameter of the adsorbent uniform.

[0065] The uniformity coefficient of the adsorbent is preferably 2.0 or less, more preferably 1.0 to 2.0, and even more preferably 1.0 to 1.6, since this can suppress pressure loss when the adsorbent is packed into a column and a liquid is passed through it. In this specification, the uniformity coefficient of an adsorbent is an index of the particle size distribution width, and is defined as the value obtained by dividing the particle size of the largest 40% of the particles in the volume distribution of the adsorbent by the particle size of the largest 90% of the particles.

[0066] The adsorbent is preferably porous because it can efficiently remove impurities such as aldehydes and organic acids from water-insoluble organic compounds such as fats and oils.

[0067] The specific surface area of the adsorbent is 1m 2 / g~1000m 2 / g is preferred, and 10m 2 / g~500m 2 / g is more preferable. 2 / g or more, the frequency of contact of impurities, such as aldehydes and organic acids, with the surface of the adsorbent is excellent. 2 When the saturation energy is 0.1 to 1.0 wt %, the impurities such as aldehydes and organic acids are not easily hindered from diffusing and penetrating into the pores of the adsorbent, resulting in excellent adsorption. In this specification, the specific surface area of the adsorbent is measured by the nitrogen gas adsorption method (BET method). Specifically, the amount of monolayer adsorption is calculated from the pressure change before and after nitrogen gas adsorption using the BET equation, and the specific surface area of the adsorbent is calculated from the cross-sectional area of one nitrogen gas molecule, according to ISO 9277.

[0068] When the adsorbent is a resin, the specific surface area of the adsorbent can be adjusted by setting the reaction conditions for polymerization, the conditions for introducing a crosslinked structure, and the like.

[0069] The pore diameter of the adsorbent is preferably 1 nm to 1000 nm, more preferably 2 nm to 500 nm, and even more preferably 3 nm to 200 nm. When the pore diameter of the adsorbent is 1 nm or more, the frequency of contact of impurities such as aldehydes and organic acids with the adsorbent surface is excellent. When the pore diameter of the adsorbent is 1000 nm or less, the mechanical strength of the adsorbent is excellent, the generation of spaces inside the pores that do not contribute to adsorption can be suppressed, and the adsorption of impurities such as aldehydes and organic acids is excellent. In this specification, the pore diameter of an adsorbent is the most frequent diameter measured by mercury porosimetry when the most frequent diameter is 100 nm or greater, or by nitrogen gas adsorption when the most frequent diameter is less than 100 nm. Specifically, in the case of mercury porosimetry, pressure is applied to the adsorbent to cause mercury to penetrate the pores, and the pore diameter is calculated using the Washburn equation based on the pressure value and the corresponding volume of penetrated mercury, assuming that the pores are cylindrical. ISO 15901-1 is applied mutatis mutandis. In the case of nitrogen gas adsorption, ISO 15901-2 is applied mutatis mutandis.

[0070] When the adsorbent is a resin, the pore diameter of the adsorbent can be adjusted by setting the polymerization conditions for suspension polymerization or emulsion polymerization, specifically, the type and amount of the monomer, the type and amount of the porosifying agent, the type and amount of the polymerization initiator, etc.

[0071] The pore volume of the adsorbent is preferably 0.01 mL / g to 3.0 mL / g, more preferably 0.1 mL / g to 2.5 mL / g, and even more preferably 0.2 mL / g to 2.0 mL / g. When the pore volume of the adsorbent is 0.01 mL / g or more, the adsorbent has excellent adsorption properties for impurities such as aldehydes and organic acids. When the pore volume of the adsorbent is 3.0 mL / g or less, the adsorbent has excellent mechanical strength. In this specification, the pore volume of an adsorbent is the most frequent volume measured by mercury intrusion porosimetry when the most frequent diameter is 100 nm or greater, and by nitrogen gas adsorption when the most frequent diameter is less than 100 nm. Specifically, in the case of mercury intrusion porosimetry, pressure is applied to the adsorbent to cause mercury to penetrate the pores, and the pore volume is calculated using the Washburn equation based on the pressure value and the corresponding volume of penetrated mercury, assuming that the pores are cylindrical. ISO 15901-1 is applied mutatis mutandis. In the case of nitrogen gas adsorption, ISO 15901-2 is applied mutatis mutandis.

[0072] When the adsorbent is a resin, the pore volume of the adsorbent can be adjusted by setting the reaction conditions for polymerization, the conditions for introducing a crosslinked structure, and the like.

[0073] The amount of compounds having a primary amino group in the adsorbent can be determined by the nitrogen content or total exchange capacity.

[0074] The nitrogen content of the adsorbent is preferably 0.3% by mass to 30% by mass, and more preferably 0.5% by mass to 25% by mass, based on 100% by mass of the adsorbent. When the nitrogen content of the adsorbent is 0.3% by mass or more, the adsorbent has a sufficient number of primary amino groups, resulting in excellent adsorption of impurities such as aldehydes and organic acids. When the nitrogen content of the adsorbent is 30% by mass or less, the adsorbent has excellent mechanical strength and a pore volume sufficient to allow impurities such as aldehydes and organic acids to diffuse and penetrate sufficiently, resulting in excellent adsorption of impurities such as aldehydes and organic acids. In this specification, the nitrogen content of the adsorbent is calculated from the total exchange capacity of the adsorbent, which will be described later.

[0075] The total exchange capacity of the adsorbent is preferably 0.1 meq / g to 20 meq / g, and more preferably 0.2 meq / g to 10 meq / g. When the total exchange capacity of the adsorbent is 0.1 meq / g or more, the adsorbent has excellent adsorption properties for impurities such as aldehydes and organic acids. When the total exchange capacity of the adsorbent is 20 meq / g or less, the adsorbent has excellent mechanical strength and a pore volume sufficient to allow impurities such as aldehydes and organic acids to diffuse and penetrate sufficiently, resulting in excellent adsorption properties for impurities such as aldehydes and organic acids. In this specification, the total exchange capacity of the adsorbent is calculated from the measurement results obtained by precisely weighing out an amount equivalent to 0.5 g to 1.5 g of dried adsorbent, adding it to 250 mL of 0.2 mol / L hydrochloric acid, shaking it at 30°C for 8 hours, and then measuring the hydrochloric acid concentration of the supernatant by titration.

[0076] (Method for removing impurities) The method for removing impurities of the present invention is a method for removing impurities in water-insoluble organic compounds using the adsorbent of the present invention. The impurities in the adsorbent and water-insoluble compound of the present invention are as described above.

[0077] Examples of methods for removing impurities include a batch treatment method in which a liquid containing a water-insoluble organic compound is mixed and contacted with an adsorbent in a container, and a column treatment method in which a column is filled with an adsorbent and a liquid containing a water-insoluble organic compound is passed through the column, etc. Among these methods for removing impurities, the column treatment method is preferred because it allows impurities such as aldehydes and organic acids to be efficiently adsorbed onto the adsorbent.

[0078] In the method of the present invention, water-insoluble organic compounds, such as fats and oils, may be dissolved in a solvent and then adsorbed onto the adsorbent of the present invention, or may be adsorbed directly onto the adsorbent of the present invention. However, since this allows the step of removing the solvent after adsorption to be omitted, it is preferable to adsorb the compounds directly onto the adsorbent of the present invention.

[0079] (Application) The adsorbent of the present invention exhibits excellent adsorption properties, particularly for impurities such as aldehydes and organic acids in water-insoluble organic compounds such as fats and oils, and can efficiently produce water-insoluble organic compounds such as fats and oils from which impurities such as aldehydes and organic acids have been highly removed on an industrial scale. Therefore, the adsorbent is of extremely high practical value in the edible fat and oil industry. [Example]

[0080] The present invention will be explained in more detail below using examples, but the present invention is not limited to the description of the following examples as long as it does not deviate from the gist of the invention.

[0081] (Volume average particle size) The volume average particle diameter of the adsorbents obtained in the examples was measured using an optical microscope (model name "SMZ1500", manufactured by Nikon Corporation) by measuring the particle diameters of 100 randomly selected particles of the adsorbent, and the volume median diameter was calculated from the particle diameter distribution.

[0082] (Uniformity coefficient) The uniformity coefficient of the adsorbents obtained in the examples was determined by measuring the particle diameters of 100 randomly selected particles of the adsorbent using an optical microscope (model name "SMZ1500", manufactured by Nikon Corporation), and dividing the particle diameter of the largest 40% of the particles by the particle diameter of the largest 90% of the particles.

[0083] (specific surface area) The specific surface areas of the polymers used in the examples and the adsorbents obtained in the examples were measured by weighing the dried adsorbents and using a specific surface area measuring device (model name "Flowsorb III", manufactured by Micromeritics) by the nitrogen gas adsorption method (BET method).

[0084] (Pore diameter / pore volume) The pore diameters and pore volumes of the polymers used in the examples and the adsorbents obtained in the examples were measured by mercury intrusion using an automatic porosimeter (model name "Autopore 9520", manufactured by Micromeritics Co., Ltd.) or by nitrogen gas adsorption using a pore size distribution analyzer (model name "ASAP2400", manufactured by Micromeritics Co., Ltd.).

[0085] (Nitrogen content / total exchange capacity) The nitrogen content and total exchange capacity of the adsorbents obtained in the examples were calculated from the measurement results after precisely weighing an amount equivalent to 0.5 g to 1.5 g of dried adsorbent, adding it to 250 mL of 0.2 mol / L hydrochloric acid, and shaking it at 30°C for 8 hours to measure the hydrochloric acid concentration of the supernatant by titration.

[0086] [Example 1] <Production of adsorbent> It consists of 20% by mass of structural units derived from glycidyl methacrylate and 80% by mass of structural units derived from ethylene glycol dimethacrylate, and has a specific surface area of 305 m 2To 40 parts by mass of a polymer having a pH of 1.0 / g, a pore diameter of 120.4 nm, and a pore volume of 1.06 mL / g, 140 parts by mass of diethylene glycol dimethyl ether and 60 parts by mass of polyethyleneimine (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., molecular weight 600) were added and stirred to form a suspension. The suspension was heated to 80°C and reacted for 6 hours. After cooling, the resulting particles were washed with water. 200 parts by mass of sulfuric acid with a concentration of 10% by mass was added to the particles and stirred to form a suspension. The suspension was heated to 50°C and maintained for 5 hours to inactivate unreacted epoxy groups by adding water. After cooling, the resulting particles were washed with water and the ion exchange groups were regenerated with a 2 mol / L aqueous sodium hydroxide solution. Particles with particle diameters of 75 μm to 220 μm were selected using a sieve to obtain adsorbent (1) having primary amino groups. The resulting adsorbent (1) had a specific surface area of 113 m 2 / g, pore diameter 38.2 nm, pore volume 0.76 mL / g, nitrogen content 4.3 mass%, and total exchange capacity 3.09 meq / g.

[0087] <Adsorption treatment> To an oil containing 1.8143 parts by mass of triolein (manufactured by Nacalai Tesque Inc.) and 0.0035 parts by mass of (E,E)-2,4-decadienal (manufactured by Tokyo Chemical Industry Co., Ltd.) (addition amount 1920 ppm), 0.0999 parts by mass of adsorbent (1) was added, and the mixture was allowed to stand at 25 ° C. for 18 hours to perform an adsorption treatment. The (E,E)-2,4-decadienal in the oils and fats after the adsorption treatment was analyzed by high performance liquid chromatography under the following conditions. Column: Cadenza CD-C18 (trade name, manufactured by Intact, inner diameter 4.6 mm, length 75 mm) Column temperature: 40℃ Eluent: acetonitrile / water = 70 / 30 Flow rate: 1.00mL / min Injection volume: 2μL Detection: UV absorption detector (wavelength 210 nm) The obtained chromatogram is shown in Figure 1. The amount of (E,E)-2,4-decadienal in the oil before and after the adsorption treatment, as determined by high-performance liquid chromatography analysis, was reduced from 1.92 mg / g to 0.67 mg / g (reduction rate: 65.2%).

[0088] [Example 2] <Production of adsorbent> A polymerization bath was prepared by mixing 362 parts by weight of demineralized water, 241 parts by weight of ammonium sulfate, and 6.20 parts by weight of an aqueous solution of polydiallyldimethylammonium chloride (polymer concentration 18% by weight, weight-average molecular weight 500,000). A monomer solution was prepared by mixing 100 parts by weight of N-vinylformamide, 11.1 parts by weight of divinylbenzene, 23.8 parts by weight of ethyl acetate, 47.6 parts by weight of acrylonitrile, and 0.79 parts by weight of 2,2'-azobis(2,4-dimethylvaleronitrile) (trade name "V-65" manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.). The monomer solution and the polymerization bath were mixed and stirred at 100 rpm while purging with nitrogen. After 30 minutes, the temperature was raised, and polymerization was carried out at 40°C for 100 minutes, then at 50°C for 60 minutes, and then at 60°C for 30 minutes. After polymerization, the mixture was filtered, washed with water, and filtered again, yielding hydrous spherical polymer particles. To 100 parts by mass of the obtained polymer spherical particles, 150 parts by mass of a 24% by mass aqueous solution of sodium hydroxide was added, and the mixture was hydrolyzed with stirring at 90° C. for 8 hours. After washing with water and filtration, an adsorbent (2) having a primary amino group was obtained. The resulting adsorbent (2) had a volume average particle diameter of 685 μm, a uniformity coefficient of 1.54, and a specific surface area of 4 m 2 / g, pore diameter 41.8 nm, pore volume 0.01 mL / g, nitrogen content 9.6 mass%, and total exchange capacity 6.87 meq / g.

[0089] <Adsorption treatment> To an oil containing 1.8143 parts by mass of triolein (manufactured by Nacalai Tesque Inc.) and 0.0035 parts by mass of (E,E)-2,4-decadienal (manufactured by Tokyo Chemical Industry Co., Ltd.) (addition amount 2010 ppm), 0.1020 parts by mass of adsorbent (2) was added, and the mixture was left to stand at 25 ° C. for 18 hours to perform an adsorption treatment. After the adsorption treatment, (E,E)-2,4-decadienal in the oil was analyzed by high performance liquid chromatography in the same manner as in Example 1. The obtained chromatogram is shown in Figure 2. The amount of (E,E)-2,4-decadienal in the oil before and after the adsorption treatment, as determined by high-performance liquid chromatography analysis, was reduced from 2.01 mg / g to 1.87 mg / g (reduction rate: 6.7%).

[0090] [Reference example] An oil containing 0.7651 parts by mass of triolein (manufactured by Nacalai Tesque, Inc.) and 0.0017 parts by mass (addition amount 2270 ppm) of (E,E)-2,4-decadienal (manufactured by Tokyo Chemical Industry Co., Ltd.) was analyzed by high performance liquid chromatography in the same manner as in Example 1. The obtained chromatogram is shown in FIG.

[0091] As is clear from the above results, the adsorbent of the present invention was able to adsorb and remove aldehydes in fats and oils with high efficiency using a simple treatment method. [Industrial Applicability]

[0092] The adsorbent of the present invention exhibits excellent adsorption properties for impurities, such as aldehydes and organic acids, in water-insoluble organic compounds, such as fats and oils, and can efficiently produce, on an industrial scale, water-insoluble organic compounds, such as fats and oils, from which impurities, such as aldehydes and organic acids, have been highly removed. Therefore, the adsorbent is of extremely high practical value in the edible fat and oil industry.

Claims

1. An adsorbent for removing impurities including aldehydes and organic acids from water-insoluble organic compounds including fats and oils, the adsorbent containing a resin and having a primary amino group immobilized thereon by a covalent bond. The adsorbent, wherein the resin comprises at least one resin selected from the group consisting of an acrylic resin and a polyvinylamine resin.

2. The adsorbent according to claim 1 , wherein the resin has a cross-linked structure.

3. The acrylic resin contains an epoxy group-containing (meth)acrylate unit and a crosslinkable (meth) 3. The adsorbent of claim 1 or 2, comprising acrylate units.

4. The adsorbent according to claim 1 or 2, wherein the polyvinylamine-based resin contains an N-vinylcarboxylic acid amide unit.

5. The adsorbent according to any one of claims 1 to 4, wherein the primary amino group is introduced by at least one selected from the group consisting of polyalkylene polyamine, polyvinyl amine, and polyallyl amine.

6. The adsorbent according to any one of claims 1 to 5, which has porosity.

7. The adsorbent according to claim 6, wherein the pore diameter is from 1 nm to 1000 nm.

8. A method for removing impurities, comprising removing impurities including aldehydes and organic acids from water-insoluble organic compounds including fats and oils using the adsorbent according to any one of claims 1 to 7.

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