JPH07108145A - Composite reverse-osmotic membrane - Google Patents

Abstract

PURPOSE:To provide a composite reverse-osmotic membrane having high desalting property and water permeability with a low pressure operation and excellent in chlorine resistance in the composite reverse-osmotic membrane for selectively penetrating and separating a component in a liquid mixture. CONSTITUTION:In the composite reverse-osmotic membrane composed of a thin film and a slightly porous supporting body supporting the thin film, the thin film is composed mainly of (a) an amine component containing at least one kind selected among amine compounds, which are substantially monomers and have at least two primary and/or secondary amino groups, and (b) a polyamide formed from a acid halide component composed mainly of an acid halide containing >=80% tetrahydrofuran-2,3,4,5-tetracarboxylic halide, in which the angle (phi) of torsion exhibiting relative position of at least one pair of adjacent acid halides is in positional relation except phi=0 deg. to + or -60 deg. according to the designation of conformation by IUPAC recommendation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite reverse osmosis membrane for selectively permeating and separating components in a liquid mixture, and more specifically, a thin film containing a polyamide having a specific structure as a main component is formed on a support. The present invention relates to a composite reverse osmosis membrane formed by.
Such a composite reverse osmosis membrane is preferably used for the production of ultrapure water, desalination of brackish water, etc., and also, from stains and the like that cause pollution such as dyeing wastewater and electrodeposition paint wastewater, a pollution source or It is possible to remove and collect effective substances, and thus contribute to the closure of wastewater.

[0002]

2. Description of the Related Art Conventionally, as a semi-permeable membrane used industrially, for example, a lob type membrane having an asymmetric structure made of cellulose acetate is known. However, such a semi-permeable membrane made of cellulose acetate is inferior in hydrolysis resistance, microbial resistance, chemical resistance and the like, and further, pressure resistance and durability are not sufficient, so that it is a device having high permeability. It was difficult to do so, and the application had to be limited. Therefore, in order to eliminate the above-mentioned drawbacks of the asymmetric semipermeable membrane made of cellulose acetate, in recent years, for example,
A semipermeable membrane made of aromatic polyamide (US Pat. No. 3,567,632), crosslinked polyamic acid (JP-A-56-3769, etc.), polybenzimidazole (JP-A-58-92403, etc.), etc. has been proposed. A semipermeable membrane made of such a polymer is
Although it is possible to eliminate some of the drawbacks of the asymmetric semipermeable membrane made of cellulose acetate, it is still inferior in selective separation and permeation performance.

Therefore, as a semipermeable membrane having a structure different from that of an asymmetric semipermeable membrane, a composite semipermeable membrane formed by forming an active thin film having substantially selective separation on a microporous support membrane is known, for example. U.S. Pat.Nos. 3,744,642, 4,039,440, 4,25
9,183, JP-A-55-147106, JP-A-58-2430
As described in No. 3, JP-A-63-197501 and the like, various developments have been made in recent years. In many of these, in order to obtain high water permeability, the thin film is made of polyamide or polyurea, and generally, an aqueous solution of a polyfunctional amino compound having two or more amino groups in the molecule and an amino acid contained in these polyfunctional amino compounds are used. On the support film by interfacial reaction with a hydrocarbon solution of a polyfunctional compound having two or more functional groups capable of reacting with a group in the molecule (for example, a polyfunctional acid halide compound). It is obtained by forming an ultrathin film made of polyamide or polyurea.

[0004]

Many of the polyfunctional acid halide compounds used here are aromatic compounds, and these polyfunctional aromatic acid halides are generally difficult to handle and have poor reactivity. Furthermore, there was a problem of substitution with an aromatic ring.

Therefore, as new acid halides replacing these polyfunctional aromatic acid halides, aliphatic or alicyclic polyfunctional acid halides have been attracting attention from the viewpoint that their reactivity is good. A semipermeable composite membrane (Japanese Patent Laid-Open No. 62-247808) using tetrahydrofuran-2,3,4,5-tetracarboxylic acid chloride which is a cyclic polyfunctional acid halide is known. However, there is a problem that the composite membrane described in this publication is inferior in desalination performance and water permeation performance.

The object of the present invention is, unlike the conventional polyfunctional aromatic acid halides, various kinds of alicyclic polyfunctional acid halides such as tetrahydrofuran-2,3,4,5-tetracarboxylic acid chloride. An object of the present invention is to provide a composite reverse osmosis membrane having excellent chlorine resistance as well as having extremely high water permeability and desalting property by low pressure operation by controlling the structure of isomers.

[0007]

Means for Solving the Problems The inventors of the present invention have conducted diligent research to obtain a composite reverse osmosis membrane having high desalination and water permeability by a low pressure operation and further excellent in chlorine resistance.
In forming a membrane, by using a composite reverse osmosis membrane provided with a thin film made of a polymer obtained by using a specific acid halide compound having an isomer structure controlled to a specific structure as an acid component, the above-mentioned problems The present invention can be remarkably improved.

That is, the present invention has the following configuration. "In a composite reverse osmosis membrane comprising a thin film and a microporous support supporting the thin film, the thin film comprises (a) an essentially monomeric compound having at least two primary or / and secondary amino groups. The twist angle (φ) indicating the relative position of the amine component containing at least one selected from the group of amine compounds and (b) at least one pair of adjacent acid halide groups is φ = Tetrahydrofuran having a positional relationship other than 0 ° to ± 60 ° -2,3,4,5-
A composite reverse osmosis membrane comprising a polyamide formed from an acid halide component containing an acid halide containing 80% or more of a tetracarboxylic acid halide as a main component, as a main component. "

In the present invention, the amine component (a) forming a polymer with the acid halide compound is selected from an essentially monomeric amine compound having at least two primary or / and secondary amino groups. There is no particular limitation as long as it is a polyfunctional amine containing at least one of the amine compounds mentioned above, and examples thereof include aromatic, aliphatic, or alicyclic polyfunctional amines.

Examples of such aromatic polyfunctional amine compounds include m-phenylenediamine, p-phenylenediamine, 1,3,5-triaminobenzene, 1,2,4-triaminobenzene and 3,5-diamino. Examples thereof include benzoic acid, 2,4-diaminotoluene, 2,4-diaminoanisole, amidole and xylylenediamine. Examples of the aliphatic polyfunctional amine compound include ethylenediamine, propylenediamine, tris (2-diaminoethyl) amine and the like. Further, as the alicyclic polyfunctional amine, for example, 1,3-
Examples thereof include diaminocyclohexane, 1,2-diaminocyclohexane, 1,4-diaminocyclohexane, piperazine, 2,5-dimethylpiperazine, 4-aminomethylpiperazine and the like. These amines may be used alone or as a mixture.

Acid halide component used in the present invention
(b) shows that the twist angle (φ) indicating the relative position of at least a pair of adjacent acid halide groups has a positional relationship other than φ = 0 ° to ± 60 ° according to the conformational display according to the IUPAC recommendation. Franc-2,3,4,5-
80% or more of tetracarboxylic acid halide, preferably 9
The main component is an acid halide containing 0% or more, particularly preferably 100% as much as possible. Alternatively, the acid halide component used in the present invention is the above acid halide component.
(b) wherein at least a pair of adjacent acid halide groups are in trans form with each other, tetrahydrofuran-2α, 3
80% or more of β, 4α, 5α-tetracarboxylic acid halide,
It is preferably 90% or more, particularly preferably 10 as much as possible.
The main component is an acid halide containing 0%. In addition, since at least a pair of adjacent carboxylic acid halides are trans isomers to each other, in addition to the above -2α, 3β, 4α, 5α-, -2β, 3α, 4α, 5α-, -2α, 3β, 4β, 5α- Or -2α, 3
There are β, 4α, 5β- isomers, which may be used alone or as a mixture. Alternatively, the acid halide component used in the present invention is the above acid halide component (b),
Acid halide containing 80% or more, preferably 90% or more, particularly preferably 100% of tetrahydrofuran-2α, 3β, 4α, 5β-tetracarboxylic acid halide having adjacent acid halide groups in trans form Is the main ingredient. In both cases, when the content is less than 80% and the content of the cis isomer exceeds 20%, there is a problem that the obtained composite reverse osmosis membrane has poor chlorine resistance and poor practicality.

Next, a method for preparing the acid halide compound used in the present invention will be described below. The acid halide compound can be obtained by acid-compounding a compound in an acid state with a halogenating reagent such as thionyl chloride or phosphorus pentachloride. At this time, an acid halide compound satisfying the above conditions can be preferentially obtained by using a specific halogenating reagent.

A compound satisfying a relationship other than φ = 0 ° to ± 60 ° by isomerizing an acid in which the twist angle of the adjacent acid is φ = 0 ° to ± 60 ° before the acid halide is formed. After that, it can be converted into an acid halide. The method of such isomerization is not particularly limited, but for example, 1. Compounds in the acid state, such as LiOH, KOH, NaOH
Neutralize with a base such as, and heat and / or pressurize. 2. The compound in the acid state is esterified, heated and / or
Or pressurize. (At this time, the hydrolysis reaction may be performed at the same time.) And the like.

Specifically, most of this compound is cis-type tetrahydrofuran-2,3,4,5-tetracarboxylic acid (Ald
(rich company) in accordance with (German published 2,105,010) in a thermal isomerization treatment in an aqueous solution to increase the ratio of trans-hydrogenated tetrahydrofuran-2α, 3β, 4α, 5β-tetracarboxylic acid to 70% or more. According to a conventional method, it can be obtained by acid chloride formation using a halogenating reagent of thionyl chloride and / or phosphorus pentachloride. In order to obtain tetrahydrofuran-2α, 3β, 4α, 5β-tetracarboxylic acid chloride with an isomerization rate of 100%, the above-mentioned starting material, tetrahydrofurano-2α, 3β, 4α, 5β-tetracarboxylic acid, is converted into acetic acid. A method in which recrystallization is performed using a solvent such as ethyl, the trans isomer ratio is set to 100%, and then acid chloride is formed is preferably used. On the other hand, the method for producing an acid halide containing 80% or more of tetrahydrofuran-2α, 3β, 4α, 5α-tetracarboxylic acid halide in which a pair of adjacent carboxylic acid halide groups are mutually in trans form is Hydrofuran-2α, 3α, 4α, 5α-tetracarboxylic acid can be obtained by heating to 100 ° C. with phosphorus pentachloride in an arbitrary solvent. The synthetic method shown here is an example, and the isomerization method and the like are not limited at all. Confirmation of cis / trans is possible by Phase Sens.
It can be performed accurately by itive NOESY. For details, see Noggle, JH, Schirmer, re, "The nucle
The structure may be determined by measurement according to the method described in "ar overhouser effect" (Academic Press. NY) (1971).

The most widely used method for determining the twist angle (φ) showing the relative position of adjacent acid halide groups in the present invention is ¹ H-NMR. ^{In 1} H-NMR, the signal of a certain proton is split by the interaction with a nearby proton, and the position of the signal is affected by other substituents and shifted. Then, the magnitude of such influence is governed by the distance from the substituents. Therefore, ¹ H-NMR is an effective means for measuring the distance between protons and substituents, and as a means for knowing the steric structure of isomers and conformational isomers based on the difference in distance between substituents. Very good. Therefore, the twist angles of the adjacent acid halide groups can be determined based on the relationship shown below.

Hydrogen on adjacent carbons in a molecule are spin-bonded to each other, which results in signal splitting. It has been clarified that the split width of the signal due to spin coupling, that is, the spin coupling constant (J value) is determined by the twist angle formed by H-C-C-H. That is, the twist angle (φ) and the binding constant (J
_vic ) values, J _vic (Hz) = 8.5 cos ² φ−0.28 (0 ° ≦ φ ≦ 90 °) J _vic (Hz) = 9.5 cos ² φ−0.28 (90 ° ≦ φ ≦ 180
°) is established. Although the J value is somewhat affected by the electronegativity of the substituent, this relational expression generally applies well. If the twist angle formed by hydrogen bonded to the adjacent carbon is clarified by the above formula, the angle formed by the acid halide group on the same carbon is determined by the relative relationship with hydrogen.

Therefore, the twist angle (φ) of the adjacent acid halide groups of the isomer structure is out of the above range,
It can be easily determined using ¹ H-NMR as described above.

The acid halide component (b) used in the present invention contains an aromatic, aliphatic or alicyclic polyfunctional acid halide having at least two acid halide groups in addition to the specific acid halide described above. You can leave.

The compound having such a bifunctional acid halide group is not particularly limited, and examples thereof include biphenyldicarboxylic acid dichloride, biphenylenedicarboxylic acid dichloride, terphenyldicarboxylic acid dichloride, quaterphenyldicarboxylic acid dichloride, methylene-dibenzoic acid. Dichloride, isolopyridene dibenzoic acid dichloride, bibenzyl dicarboxylic acid dichloride, stilbene dicarboxylic acid dichloride, transdicarboxylic acid dichloride, pseudodicarboxyparacyclophane dichloride, carbonyl dibenzoic acid dichloride, oxy dibenzoic acid dichloride, dithio dibenzoic acid dichloride , Azobenzenedicarboxylic acid dichloride, ethylenedithiodibenzoic acid dichloride, bis (p
-Carboxyphenyl) phenylphosphine oxide dichloride, bis (p-carboxymethoxyphenyl) methylphosphine oxide dichloride, dibenzofurandicarboxylic acid dichloride, dimixodibenzothiophene dicarboxylic acid dichloride, oxoxanthene dicarboxylic acid dichloride, dibenzodioxin dicarboxylic acid dichloride, phenoxy Satinine dicarboxylic acid dichloride, thianthrene dicarboxylic acid dichloride, oxophenylphenoxysaphosphine dicarboxylic acid dichloride, phenazine dicarboxylic acid dichloride, terephthalic acid chloride, isophthalic acid chloride, 1,3-cyclohexanedicarboxylic acid chloride,
Aromatic bifunctional acid chlorides such as 1,4-cyclohexanedicarboxylic acid chloride, aliphatic 2 such as glutaryl chloride, adipoyl chloride and sebacyl chloride
Examples thereof include alicyclic bifunctional acid halides such as functional acid halides, cyclopentanedicarboxylic acid chloride, cyclobutanedicarboxylic acid chloride, cyclohexanedicarboxylic acid chloride and tetrahydrofurandicarboxylic acid chloride. Further, for example, those having a pendant benzene ring in the side chain such as biphenyl succinic acid dichloride, methylene biphenyl dipropionic acid dichloride, oxybiphenyl diacetic acid dichloride, isopropylidene biphenyl dioxydiacetic acid dichloride, etc. Is mentioned.

Further, the benzene ring in the bifunctional acid halide may be substituted with an alkylene group having 1 to 4 carbon atoms, halogen or the like.

In the present invention, it is preferable to mix a polyfunctional acid halide component having at least three acid halide groups with these difunctional acid halide components, and thereby, as a crosslinked polyamide, various resistances are further improved. There is an effect that it can be improved.

The polyfunctional acid halide having at least three acid halide groups is not particularly limited, and examples thereof include aromatic, aliphatic, alicyclic and other polyfunctional acid halides. Examples of the aromatic polyfunctional acid halide include trimesic acid halide and the like. Examples of the aliphatic polyfunctional acid halide include propane tricarboxylic acid chloride, butane tricarboxylic acid chloride, pentane tricarboxylic acid chloride and the like. Examples of the alicyclic polyfunctional acid halide include cyclobutane tricarboxylic acid chloride, cyclobutane tetracarboxylic acid chloride, cyclopentane tricarboxylic acid chloride, cyclopentane tetracarboxylic acid chloride, cyclohexane tricarboxylic acid chloride and the like.

In the present invention, the amine component (a) is used.
And the acid halide component (b) are subjected to interfacial polymerization to obtain a composite reverse osmosis membrane in which a thin film containing a crosslinked polyamide as a main component is formed on a microporous support membrane.

In the present invention, by using the polyfunctional acid halide compound having such a specific structure as an acid component, as a result, a composite reverse osmosis membrane having excellent desalination property, water permeability and chlorine resistance can be obtained. The reason for this is not clear, but it is presumed that the steric hindrance of adjacent acid halide groups is reduced, the resulting polymer has a high molecular weight, and a crosslinked structure is easily formed.

In the present invention, the microporous support membrane for supporting the thin film is not particularly limited as long as it can support the thin film, and examples thereof include polysulfone, polyarylethersulfone such as polyethersulfone, polyimide, polyfluorinated. Although various ones such as vinylidene can be mentioned, in particular, since they are chemically, mechanically and thermally stable,
A microporous support membrane made of polysulfone or polyarylethersulfone is preferably used. Such a microporous support membrane is usually about 25 to 125 μm, preferably about 40 to 125 μm.
It has a thickness of 75 μm, but is not necessarily limited thereto.

More specifically, a first layer consisting of an aqueous solution containing the amine component (a) is formed on the microporous support film, and then a water-containing layer containing the acid halide component (b) is formed. It can be obtained by forming a layer made of a miscible organic solvent solution on the first layer, performing interfacial polycondensation, and forming a thin film made of crosslinked polyamide on the microporous support film.

The aqueous solution containing a polyfunctional amine is further added with a water-soluble material such as polyvinyl alcohol, polyvinylpyrrolidone or polyacrylic acid in order to facilitate film formation or to improve the performance of the obtained composite reverse osmosis membrane. A polymer or a polyhydric alcohol such as sorbitol or glycerin may be contained.

The amine salts described in JP-A-2-187135, such as salts of tetraalkylammonium halides or trialkylamines with organic acids, can also be added to the support membrane of the amine solution to facilitate membrane formation. It is preferably used in terms of improving the absorbability, accelerating the condensation reaction, and the like.

Further, a surfactant such as sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, sodium lauryl sulfate can be contained. These surfactants are effective in improving the wettability of the aqueous solution containing the polyfunctional amine to the microporous support film. further,
In order to accelerate the polycondensation reaction at the interface, sodium hydroxide or trisodium phosphate capable of removing hydrogen halide generated in the interface reaction is used, or as a catalyst,
It is also beneficial to use quaternary ammonium salts, acylation catalysts, phase transfer catalysts and the like.

The organic solvent for preparing the water-immiscible organic solvent solution containing the acid halide component may be an organic solvent which dissolves the acid halide component used well and does not dissolve the microporous support membrane used. For example, Freon (trademark of DuPont) containing hydrocarbons such as n-hexane and cyclohexane, and trichlorotrifluoroethane.
Examples thereof include halogenated hydrocarbons.

In the organic solvent solution containing the acid halide (b) and the aqueous solution containing the polyfunctional amine, the concentrations of the acid halide and the polyfunctional amine are not particularly limited, but the acid halide is usually 0.01 5% by weight, preferably 0.05 to 1% by weight, and the polyfunctional amine is usually 0.1% by weight.
-10% by weight, preferably 0.5-5% by weight.

When hydrogen halide is produced as a by-product in the process of obtaining the polymer thin film, it is preferable to allow an acid acceptor to exist in the first solution to promote the polycondensation reaction. As such an acid acceptor, it is also advantageous to use amines such as triethylamine, sodium hydroxide or the like, or to use a quaternary ammonium salt, an acylation catalyst, a phase transfer catalyst or the like as a catalyst.

Thus, after coating the microporous support membrane with an aqueous solution containing a polyfunctional amine, and then coating an organic solvent solution containing the difunctional acid halide compound of the present invention thereon, Remove each excess solution, then
Usually about 20-150 ° C, preferably about 70-130 ° C
Then, it is dried by heating for about 1 to 10 minutes, preferably about 2 to 8 minutes to form a water-permeable thin film made of crosslinked polyamide. This thin film usually has a thickness of about 0.05 to 1 μm,
It is preferably in the range of about 0.15 to 0.5 μm.

Further, the composite reverse osmosis membrane of the present invention has
As described in Japanese Patent No. 36803, it is also possible to further improve the salt blocking performance by performing a chlorine treatment with hypochlorous acid or the like.

[0035]

INDUSTRIAL APPLICABILITY The composite reverse osmosis membrane according to the present invention comprises a thin film containing, as a main component, a polymer obtained by using a polyfunctional acid halide compound having a specific structure as an acid component. It has extremely high water permeability and desalination properties depending on the operation, and also has excellent chlorine resistance. For example, desalination by desalination of brackish water, seawater, etc., and production of ultrapure water required for semiconductor production. And the like can be suitably used.

[0036]

The present invention will be described below with reference to examples.
The present invention is not limited to these examples.
A polysulfone-based ultrafiltration membrane was used as the microporous support membrane. The performance of the obtained composite reverse osmosis membrane was determined by allowing the composite reverse osmosis membrane to permeate an aqueous solution of pH 6.5 containing 1500 ppm of sodium chloride at an operating pressure of 15 kg / cm ² and a temperature of 25 ° C. for 1 hour, and then The removal rate and water permeation rate were measured. The sodium chloride removal rate was determined by ordinary conductivity measurement.

Example 1 [Production of Acid Halide Compound] Tetrahydrofuran-2
α, 3β, 4α, 5β-Tetracarboxylic acid chloride was obtained by the following method. Tetrahydrofuran-2α, 3β, 4α, 5β-
A raw material having a ratio of tetracarboxylic acids to isomers of 70%, thionyl chloride (2 times mol per carboxylic acid) and 1 drop of DMF were put into heptane and heated to 60 ° C. After reacting for 4 hours at this temperature, it was cooled. After distilling excess thionyl chloride under reduced pressure, the reaction residue was extracted with heptane to obtain the desired tetrahydrofuran-2α, 3β, 4α, 5β-tetracarboxylic acid chloride.

Tetrahydrofuran-2α, 3β, 4 thus obtained
As a result of ¹ H-NMR analysis of α, 5β-tetracarboxylic acid chloride, the twist angle formed by the carboxylic acid chloride groups at the adjacent positions 1 and 2, 2, 3, 3 and 4 was φ = about 13
It was 5 °. The isomer ratio was 100%.

[Production of Composite Reverse Osmosis Membrane] 3.0 wt% of m-phenylenediamine and 0.1% of sodium lauryl sulfate.
An aqueous solution containing 1.0% by weight of triethylamine and 2.0% by weight of camphorsulfonic acid in an aqueous solution containing 25% by weight is brought into contact with the polysulfone membrane for several seconds and then drained. At this time, the film surface is swept several times with a wiper. The surface of the support thus coated with m-aminophenol and an amine salt was treated with the above-obtained tetrahydrofuran-2.
0.2 of α, 3β, 4α, 5β-tetracarboxylic acid chloride
Contact with a hexane solution containing 5% by weight. Then, the coated support was kept in a hot air dryer at 120 ° C. for 5 minutes to obtain a composite reverse osmosis membrane. When the performance of the obtained composite reverse osmosis membrane was evaluated, the salt removal rate was 99.4% and the water permeation rate was 0.
It was 8 t / m ² days.

Further, as a resistance test of the composite reverse osmosis membrane, when it was immersed in a 100 ppm sodium hypochlorite aqueous solution for 17 hours and then re-measured under the above conditions, the salt removal rate was 99.3% and the water permeation rate was 0. It was confirmed that the film performance was not deteriorated at 9 t / m ² days, and the chlorine resistance was excellent.

Example 2 [Production of Acid Halide Compound] Tetrahydrofuran-2
α, 3β, 4α, 5α-Tetracarboxylic acid chloride was obtained by the following method. Tetrahydrofuran-2α, 3α, 4α, 5α-
Tetracarboxylic acid and phosphorus pentachloride (2 moles per carboxylic acid) were placed in heptane and heated to 100 ° C.
After reacting for 4 hours at this temperature, it was cooled. After distilling excess phosphorus pentachloride under reduced pressure, the reaction residue was extracted with heptane to give the desired tetrahydrofuran-2α, 3
β, 4α, 5α-tetracarboxylic acid chloride was obtained.

Tetrahydrofuran-2α, 3β, 4 thus obtained
As a result of ¹ H-NMR analysis of α, 5α-tetracarboxylic acid chloride, α, β of adjacent carboxylic acid chlorides
Has a twist angle of about 135 °, α, α has a twist angle of about 45 °
Met. The isomer ratio was 100%.

Tetrahydrofuran-2α, 3β, 4α, 5β-
Tetracarboxylic acid chloride tetrahydrofuran-2
α, 3β, 4α, 5 α -Tetracarboxylic acid chloride (isomer ratio 100%, α, β twist angle of carboxylic acid chloride is about 135 °, α, α twist angle of carboxylic acid chloride is about 45 ° The performance of the composite reverse osmosis membrane obtained in the same manner as in Example 1 except that the salt removal rate was 99.0% and the water permeation rate was 1.4 t / m ² days was changed. there were. 100 pp as a resistance test of the obtained composite reverse osmosis membrane
When the sample was immersed in an aqueous solution of sodium hypochlorite of m for 17 hours and then re-measured under the above conditions, the salt removal rate was 98.7.
%, The water permeation rate was 1.8 t / m ² days, and almost no deterioration of the membrane performance was observed, and it was confirmed that the chlorine resistance was excellent.

Example 3 Tetrahydrofuran-2α, 3β, 4α, 5β-tetracarboxylic acid chloride (90%) and tetrahydrofuran-2
α, 3α, 4α, 5α- Tetracarboxylic acid chloride (10
%), The composite reverse osmosis membrane obtained in the same manner as in Example 1 had a salt removal rate of 9%.
The water permeation rate was 9.0% and the rate was 0.9 t / m ² days. As a resistance test of the obtained composite reverse osmosis membrane, it was immersed in a 100 ppm aqueous sodium hypochlorite solution for 17 hours and then re-measured under the above conditions. The salt removal rate was 98.8% and the water permeation rate was 1.1 t /. m was ² days. It was confirmed that there was almost no deterioration in the membrane performance as compared with Example 1, and the chlorine resistance was excellent.

Comparative Example 1 Tetrahydrofuran-2α, 3β, 4α, 5β-tetracarboxylic acid chloride was converted into tetrahydrofuran-2α, 3α , 4α, 5.
α -Tetracarboxylic acid chloride (isomer ratio 100
%, Carboxylic acid chloride α, α twist angle is about 45
It was °. ) Was performed in the same manner as in Example 1, except that the salt removal rate was 9%.
The water permeation rate was 8.2% and the rate was 1.5 t / m ² days. As a resistance test of the obtained composite reverse osmosis membrane, it was soaked in a 100 ppm aqueous sodium hypochlorite solution for 17 hours and then re-measured under the above-mentioned conditions. The salt removal rate was 68.7% and the water permeation rate was 3.8 t /. m was ² days. The salt removal rate was lower than that of Example 1. In particular, the performance of the composite reverse osmosis membrane was significantly reduced in the resistance test using the aqueous solution of sodium hypochlorite.

Comparative Example 2 Tetrahydrofuran-2α, 3β, 4α, 5β-tetracarboxylic acid chloride ( 70% ) and tetrahydrofuran-2
α, 3α, 4α, 5α- Tetracarboxylic acid chloride ( 30
% ), The composite reverse osmosis membrane obtained in the same manner as in Example 1 had a salt removal rate of 9%.
The water permeability was 9.2% and the permeation rate was 1.1 t / m ² days. As a resistance test of the obtained composite reverse osmosis membrane, it was immersed in a 100 ppm sodium hypochlorite aqueous solution for 17 hours and then re-measured under the above-mentioned conditions. The salt removal rate was 88.7% and the water permeation rate was 2.1 t /. m was ² days. Compared with Example 1, a large decrease in the performance of the composite reverse osmosis membrane was observed particularly in the resistance test using the sodium hypochlorite aqueous solution.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Masahiko Hirose 1-2-1, Shimohozumi, Ibaraki City, Osaka Prefecture Nitto Denko Corporation

Claims (3)

[Claims] 1. A composite reverse osmosis membrane comprising a thin film and a microporous support supporting the thin film, wherein the thin film essentially comprises (a) at least two primary or / and secondary amino groups. The amine component containing at least one selected from the group of monomeric amine compounds, and (b) the twist angle (φ) indicating the relative position of at least a pair of adjacent acid halide groups is a conformational display according to the IUPAC recommendation. According to the above, tetrahydrofuran = 2,3,4,5-with a positional relationship other than φ = 0 ° to ± 60 °
A composite reverse osmosis membrane comprising a polyamide formed from an acid halide component containing an acid halide containing 80% or more of a tetracarboxylic acid halide as a main component, as a main component. 2. An acid halide component (b) containing at least 80% of tetrahydrofuran-2,3,4,5-tetracarboxylic acid halide in which at least a pair of adjacent acid halide groups are in trans form. The composite reverse osmosis membrane according to claim 1, which comprises a halide as a main component. 3. The acid halide component (b) is tetrahydrofuran in which adjacent acid halide groups are in trans form.
-2α, 3β, 4α, 5β- tetracarboxylic acid halide 80%
The composite reverse osmosis membrane according to claim 1, wherein the acid halide contained above is a main component.