JP2987949B2 - Porous resin and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a porous resin and a method for producing the same. More specifically, the porous resin of the present invention relates to a spherical porous resin having a novel crosslinked porous structure.

[0002]

2. Description of the Related Art A porous adsorbent (hereinafter, abbreviated as a porous adsorbent), which is a three-dimensional crosslinked copolymer of an aromatic addition polymerizable monomer such as styrene and a crosslinkable monomer, is known as a porous adsorbent. Due to its hydrophobic nature, it is widely used for recovery by adsorption of useful substances contained in water or an organic solvent-water mixture, or for selective removal of impurities.

[0003] As an application field of the porous adsorbent, useful substances such as pharmaceuticals and foods are recovered from a raw fermentation solution,
In some cases, impurity components are selectively adsorbed and removed from a mixture of pharmaceuticals, foods, and the like. In the process of recovering these useful substances or purifying and separating, usually, two types of steps are performed: adsorption of a substance to be adsorbed from a solvent onto a porous adsorbent, and elution of the adsorbed substance from the porous adsorbent. included.

In order to operate these processes efficiently, it is necessary to increase the amount of the substance to be adsorbed on the porous adsorbent and to increase the recovery rate of the substance in one operation. The adsorption of the substance to be adsorbed on the porous adsorbent differs depending on the properties of the adsorbent such as porosity and hydrophilicity.

However, the porosity of the adsorbent is not compatible with the aromatic addition polymer produced when the aromatic addition polymerizable monomer and the crosslinkable monomer are copolymerized. Applied and affected by the action of the solvent or mixture thereof. In addition, the porous adsorbent composed of these aromatic cross-linked copolymers lacks affinity with an aqueous solution containing the substance to be adsorbed in the actual purification / separation process due to its hydrophobic nature, and the porous adsorbent is porous. When the sorbent is dried, a floating phenomenon in the aqueous solution to be treated often occurs.

On the other hand, as a hydrophilic aromatic cross-linked copolymer, a cross-linked copolymer obtained by solution polymerization of p-acetoxystyrene and divinylbenzene is pulverized and classified, and then the obtained copolymer particles are hydrolyzed. Crosslinked polyhydroxystyrene obtained by decomposition is known (N. Ka).
wabata et al, Ind. Eng. Chem.
Res, 1990 , 29, 1889-1893).
However, since this is a crushed product, the shape is not uniform, and it is not suitable for use as an adsorbent.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to further improve a conventional cross-linked resin, which has improved affinity with an aqueous solution containing a substance to be adsorbed and efficiently and efficiently uses a useful substance. An object of the present invention is to provide a porous adsorbent that can be removed and recovered, and to provide a useful method for producing the porous adsorbent.

[0008]

Means for Solving the Problems The present inventors have conducted intensive studies with the aim of improving an adsorbent having a high affinity for the above-mentioned aqueous solution, and as a result, have found that a resin contains a certain functional group. As a result, a target resin was obtained, and it was found that the resin could be produced by a specific method, and the present invention was completed.

That is, according to the present invention, the structural units represented by the general formulas (A), (B) and (C) described in claim 1 are each contained in an amount of 0.5 to 96% by weight, 4 to 80% by weight and 0 to 50% by weight , specific surface area of 100 m ²
/ G or more, and a spherical crosslinked porous resin having a pore volume of 0.2 ml / g or more , and m- or p-
A mixture containing 0.5 to 96% by weight, 4 to 80% by weight and 0 to 50% by weight, respectively, of an alkoxystyrene, a polyvinyl compound and a monovinyl compound other than the alkoxystyrene, based on all monomers, is used as a porous forming agent and a radical. A spherical crosslinked copolymer is obtained by suspension copolymerization in the presence of a polymerizable initiator, and the copolymer is hydrolyzed in an acidic or basic atmosphere to obtain a unit derived from alkoxystyrene. the method of manufacturing the general formula (a) wherein spherical porous resin you and converting the structure represented by the consists in.

Hereinafter, the present invention will be described in detail. The structure represented by the general formula (A) contained in the spherical crosslinked porous resin in the present invention is generally introduced by an aromatic vinyl compound which is a precursor thereof. These include, for example, ethoxystyrene, methoxystyrene, propoxystyrene, t
-Alkoxystyrenes such as butoxystyrene are used.

The alkoxystyrenes used herein are all easily converted to the structure represented by the general formula (A) under hydrolysis conditions under acidic or basic conditions. Further, compounds having a structural unit represented by the general formula (A), that is, hydroxystyrenes, are known to have higher reactivity than before, and are not suitable for performing a copolymerization reaction with the polyvinyl compound of the present invention. A method of hydrolyzing after introducing the alkoxystyrene is preferably used.

In the structural formula represented by the general formula (B), the alkyl group having 1 to 3 carbon atoms includes a methyl group and an ethyl group, and the arylene group includes a phenylene group such as a 1,4-phenylene group; Examples include naphthylene groups such as 1,4-naphthylene groups. Specific examples of the compound having the structural unit represented by the general formula (B) include an aromatic polyvinyl compound, and specifically, divinylbenzene, divinyltoluene, divinylxylene, divinylnaphthalene, and the like are used. As the compound, ethylene glycol dimethacrylate or trimethylolpropane trimethacrylate can also be used. Of these, aromatic polyvinyl compounds in which a benzene nucleus such as divinylbenzene or divinyltoluene is substituted with an alkyl group having 1 to 3 carbon atoms are useful.

Among the monovinyl compounds other than the alkoxystyrene constituting the spherical crosslinked copolymer represented by the general formula (C), examples of the aromatic monovinyl compound include styrene, vinyltoluene, vinylnaphthalene and ethylvinylbenzene. . In addition to the above aromatic vinyl compounds, aliphatic monovinyl compounds such as methyl methacrylate, acrylonitrile, 2-hydroxyethyl methacrylate, methacrylic acid, and ethyl acrylate can also be used.

These compounds may be used in an amount of from 0 to 50 based on the total amount of the vinyl monomers according to the properties of the desired porous resin.
By weight percent, the porous resin of the present invention can be produced. In producing the spherical crosslinked porous resin according to the present invention, the mixing ratio of the alkoxystyrene, the polyvinyl compound, and the monovinyl compound other than the alkoxystyrene can be changed at an arbitrary ratio. 0.5 to 96% by weight are used. In this case, if the amount is less than 0.5% by weight, the effect of the present invention is hardly obtained, and if it exceeds 96% by weight, the efficiency of the crosslinking reaction is poor and the obtained resin is not practical. The ratio of the polyvinyl compound as a crosslinking agent to the total vinyl compound is
Usually, it is selected in the range of 4 to 80% by weight, preferably 15 to 60% by weight.

The monovinyl compound and the polyvinyl compound are subjected to suspension polymerization according to a known method. In this case, as a polymerization initiator, dibenzoyl peroxide, lauroyl peroxide, t-butyl hydroperoxide, azobisisobutyronitrile, etc. And usually used in an amount of about 0.5 to 5% by weight based on all monomers. The polymerization temperature varies depending on the type and concentration of the polymerization initiator, but is usually 40 to 9
It is selected in the range of 0 ° C.

The polymer obtained by suspension polymerization according to the above known method is characterized by having a porous structure. That is, it is necessary to have a specific surface area of 100 m ² / g or more and a pore volume of 0.2 ml / g or more. Solvents used for imparting these porous structures during polymerization include, for example, aromatic compounds such as toluene and benzene, ester compounds such as ethyl acetate and butyl acetate, alcohols such as isoamyl alcohol and methyl isobutyl carbinol. , Saturated hydrocarbons such as n-heptane and isooctane, halogenated solvents such as dichloroethane and trichloroethylene, plasticizers such as dioctyl phthalate and dibutyl adipate, and polymers such as polystyrene and polyvinyl acetate are useful.

In the case where an organic solvent or a plasticizer is used, the proportion of the solvent for imparting the porous structure is 50 to 250% by weight based on all monomers, and a linear polymer such as polystyrene is used. In this case, 1 to 1
Use 20% by weight. The copolymer thus obtained is
After removing the solvent used for the suspension polymerization reaction, an acidic aqueous solution,
Alternatively, the alkoxy group is converted to a hydroxyl group by hydrolysis treatment in a basic aqueous solution. As the acidic aqueous solution, any of inorganic acids such as hydrochloric acid, sulfuric acid, and nitric acid can be used. The reaction can be allowed to proceed if the concentration is 1 mol / l or more, but the concentration is preferably 2 mol / l or more and the reaction is carried out at a temperature of 50 ° C. or more. As the basic aqueous solution, various alkaline aqueous solutions such as sodium hydroxide, potassium hydroxide and calcium hydroxide can be used. The concentration is 1 mol / l
Above, a temperature of 40 ° C. or higher is used.

The spherical porous crosslinked copolymer thus obtained can be used as a synthetic adsorbent by itself, or can be converted to an ion exchange resin or a chelate resin by sulfonation or chloromethylation and subsequent amination by a conventional method. Is also possible. When a porous adsorbent obtained by the method of the present invention is used, an appropriate solvent is selected and used for elution of the substance to be adsorbed from the adsorbent. , Chemical structure, chemical stability and the like. As a general selection of the solvent in the operation, a solvent which strongly promotes the solubility of the substance to be adsorbed is preferably used as compared with the solvent used in the step of adsorbing the substance to be adsorbed. As these solvents, for example, alcohols such as methyl alcohol, ethyl alcohol, propyl alcohol, butyl alcohol, amyl alcohol,
Ketones such as acetone and methyl isobutyl ketone, and organic solvents such as acetonitrile are used.

Further, various buffer solutions, acidic solutions and alkaline solutions which act on the ionic dissociation group of the substance to be adsorbed are used. For example, acetate buffer, phosphate buffer and the like. Alternatively, a hydrochloric acid solution, a sulfuric acid solution, a sodium hydroxide solution, an aqueous ammonia solution, or the like is used. The above-mentioned eluents are used, but these may be used alone, mixed or used one by one.

Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to these examples. In the examples, the specific surface area was measured by a nitrogen adsorption method.

[0021]

EXAMPLES Production Example 1 70 parts by weight of divinylbenzene (purity 80%, the remainder being ethylvinylbenzene), 30 parts by weight of p-tert-butoxystyrene (manufactured by Hokuko Chemical), and 100 parts by weight of toluene were mixed. A mixture of 1.0 parts by weight of benzoyl peroxide was dropped into a suspension medium containing a dispersant,
Under stirring, oil droplets formed. Heating and bath temperature 80 ℃
After that, the temperature was maintained at 80 ° C. for 10 hours to polymerize the droplets.

The obtained copolymer beads were washed with water to remove the dispersant adhering to the beads. The copolymer beads were suspended again in water, heated under stirring and kept at 95 ° C. for 5 hours to remove toluene contained in the beads.
The yield of the obtained copolymer beads was 91% based on the weight of the raw material monomer. The obtained copolymer beads (100 parts by weight) were suspended in 400 parts by weight of a 20% hydrochloric acid aqueous solution.
And kept for 5 hours.

The obtained resin was washed with a column with water to obtain a desired resin. From the weight loss in terms of dry resin, it was confirmed that 30 parts by weight of the butyl group had been removed according to the theoretical amount. This resin is referred to as Sample A.

Production Example 2 A reaction was carried out in the same manner as in Production Example 1, except that 150 parts by weight of toluene was used instead of 100 parts by weight of toluene. The yield of the obtained copolymer beads was 91% based on the weight of the raw material monomer. The obtained resin is designated as Sample B.

Production Example 3 The reaction was carried out in the same manner as in Production Example 2 except that 150 parts by weight of isooctane was used instead of 150 parts by weight of toluene. The yield of the obtained copolymer beads was 91% based on the weight of the raw material monomer. The obtained resin is designated as Sample C.

Comparative Production Example 1 70 parts by weight of divinylbenzene (purity 80%), 30 parts by weight of styrene, and 100 parts by weight of toluene were mixed.
1.0 part by weight of dibenzoyl peroxyside was mixed,
The mixture was added dropwise to a suspension medium containing a dispersant to form oil droplets under stirring. After heating and raising the bath temperature to 80 ° C,
The solution was kept at 80 ° C. for 10 hours to polymerize the droplets. The obtained copolymer beads were washed with water to remove the dispersant adhering to the beads.

The copolymer beads were suspended again in water, heated under stirring and maintained at 95 ° C. for 5 hours to remove toluene contained in the beads. The yield of the obtained copolymer beads was 91% based on the weight of the raw material monomer. The obtained resin is referred to as Sample D.

Comparative Production Example 2 70 parts by weight of divinylbenzene (purity 80%), 30 parts by weight of p-tert-butoxystyrene, 100 parts by weight of toluene
Parts by weight, and further, 1.0 part by weight of dibenzoyl peroxide was mixed and dropped into a suspending medium containing a dispersant to form oil droplets with stirring. After heating and raising the bath temperature to 80 ° C., the temperature was maintained at 80 ° C. for 10 hours to polymerize the droplets.

The obtained copolymer beads were washed with water to remove the dispersant adhering to the beads. The copolymer beads were suspended again in water, heated under stirring and kept at 95 ° C. for 5 hours to remove toluene contained in the beads.
The yield of the obtained copolymer beads was 91% based on the weight of the raw material monomer. The unhydrolyzed resin in Production Example 1 thus obtained is referred to as Sample E.

Example 1 Evaluation of Adsorption Capacity of Resin Samples A, B, C, D and E obtained in each of the above production examples were subjected to an adsorption test using a standard substance.

(Adsorption test of cephalosporin-C) An aqueous solution of cephalosporin-C (pH adjusted to 2.5 with hydrochloric acid) was added to a column filled with each sample, and the equilibrium adsorption concentration at each concentration was measured. I asked. From this equilibrium adsorption isotherm,
The equilibrium adsorption amount at the point where the external solution concentration reached 2000 ppm was determined. The results are summarized in Table 1.

Table 1 also shows the physical structures of the samples A, B, C, D, and E.

Evaluation of hydrophilicity of resin Samples A, B, C, D, and E obtained were subjected to 0.1 torr.
It was kept at 50 ° C. for 6 hours and dried. 2.0 g of each dried sample was collected and placed in a 25 ml measuring cylinder. Next, 10 ml of deionized water or 0.1 mol / l sodium hydroxide aqueous solution was added to each measuring cylinder, and the sedimentation time of each resin at the bottom of the measuring cylinder was recorded. The results are shown in Table 1.

[0034]

Industrial Applicability The present invention improves the diffusion of a substance to be adsorbed on a porous adsorbent, rapidly adsorbs the substance, and elutes the substance in a short time. It is effectively used in the field of refining pharmaceuticals and foods.

[0035]

[Table 1]

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-3-200811 (JP, A) JP-A-4-226110 (JP, A) (58) Fields investigated (Int.Cl. ⁶ , DB name) C08F 12/00-12/36 C08F 212/00-212/36

Claims (2)

(57) [Claims] 1. The structural unit represented by the general formulas (A), (B) and (C) is 0.5 to 96% by weight, respectively, and 4 to 80% by weight.
% By weight and 0 to 50% by weight , and the specific surface area is
100m ² / g or more, pore volume 0.2ml / g or more
Spherical crosslinked porous resin wherein there. Embedded image (Wherein the OH group is at the m-position or the p-position) Embedded image (In the formula, X represents an aryl group, a carboxyl group, or a carboxyl ester group which may have a substituent,
R ³ represents hydrogen or an alkyl group having 1 to 3 carbon atoms. ) 2. An m- or p-alkoxystyrene, a polyvinyl compound and a monovinyl compound other than the alkoxystyrene are added in an amount of 0.5 to 96% by weight, based on all monomers, respectively.
To 80% by weight and a mixture containing 0 to 50% by weight in the presence of a porous forming agent and a radical polymerizable initiator, are subjected to suspension copolymerization to obtain a spherical crosslinked copolymer, and the copolymer is made acidic or acidic. hydrolyzed under basic atmosphere, you and converting the structure shown units derived from alkoxy styrene by formula (a) in claim 1 wherein
Method of manufacturing a spherical shaped porous resin according to claim 1.