JPS5888007A - Separation of liquid mixture - Google Patents

Abstract

PURPOSE:To use a high molecular membrane obtained from a solution prepared by dissolving a carboxylic acid type fluorinated copolymer in a hydrophilic org. solvent, in a method for separating a mixture containing an org. liquid according to vapor separation. CONSTITUTION:In separating or concentrating a mixture comprising org. liquids or an org. liquid and water according to vapor separation, when a high molecular membrane, which is formed from a solution prepared by dissolving a copolymer consisting of a fluorinated ethylenic monomer and a carboxylic acid group containing ethylenic monomer (pref., fluorine contained one) in a hydrophilic org. solvent containing a small amount of water, is used, the efficiency of separation or concn. is enhanced and a permeation speed is also made fast. A separation temp. is selected from a range of 0-200 deg.C and pressure from a range of vacuum -100kg/cm<2>.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for separating or separating a liquid mixture containing at least an organic liquid as one of its components (hereinafter abbreviated as an organic liquid mixture) by pervaporation using a specific polymer membrane. Concerning the method of concentrating.

A process for separating organic liquid mixtures using non-porous, uniform polymeric membranes is disclosed in U.S. Patent No. 295,350.
This is taught in Specification No. 2, etc. This separation process is generally called a pervaporation process using a membrane.The liquid to be treated is supplied to the secondary side (high pressure side) of the polymer membrane, and substances that are easily permeable are transferred to the secondary side (low pressure side). This is a method of preferentially transmitting it as vapor. This membrane separation method separates or concentrates liquid mixtures that could not be separated using conventional simple methods, such as azeotropic mixtures, mixtures with close boiling points and low relative volatility, and mixtures containing substances that polymerize or modify when heated. It is attracting attention as a new way to do so.

Conventionally, membranes made of polyethylene, polypropylene, cellulose-based polymers, polyacrylonitrile, polyamide, polyester, polystyrene, polytetrafluoroethylene, or copolymers thereof have been known as polymer membranes used in such separation methods. It is being However, when an organic liquid mixture is separated by pervaporation using a fragile membrane, the following practical difficulties are observed. That is, (1) The rate of concentration (separation coefficient α□,) when an organic liquid mixture passes through a polymer membrane once is small, so in order to concentrate or separate the organic liquid mixture to the desired concentration, it is necessary to pass through a very large number of It must pass through a membrane. In general, the separation factor α
AB is as follows.

(2) Amount of permeation of the organic-organic liquid mixture through the polymer membrane (
Generally, the membrane surface area (expressed as unit membrane surface area, unit membrane thickness, and permeation amount per unit time) is small, so the membrane surface area must be made very large or the membrane thickness of the polymer membrane must be made extremely thin. Therefore, in the former case, the equipment cost becomes excessive, and in the latter case, problems arise in the strength and durability of the membrane.

As the above-mentioned improved process, a method using a polymer membrane in which sulfonic acid groups etc. are bonded to a polymer base, a method using a specific polyamide membrane, a method using an ionomer polymer membrane, etc. are disclosed in Japanese Patent Application Publication No. It is disclosed in Japanese Patent No. 52-111888, Japanese Publication No. 52-111889, Japanese Publication No. 54-33278, Japanese Publication No. 54-33279, etc.

The present inventor has conducted various studies on means for separating or concentrating various organic liquid mixtures by pervaporation.
As a result of repeated investigations, we came to the following interesting findings. That is, the carboxylic acid side chain of a carboxylic acid type fluorinated polymer is made into a 1000H form, and the polymer is heated in a hydrophilic organic solvent such as acetone, alcohol, or glycol ether in the presence of a small amount of water. They have surprisingly discovered that when added, it exhibits good solubility and can be made into a highly concentrated solution of about 20% by weight or more. The reason for this is not necessarily clear, but in the case of a hydrophilic organic solvent alone, a fluorinated polymer having a side chain in the form of -〇〇H hardly dissolves in the solvent. It is thought that the addition of water has a significant effect on the affinity between the carboxylic acid type fluorinated polymer and the hydrophilic organic solvent. According to this method, a highly concentrated organic solution with a concentration of up to about 40% by weight can be easily obtained using a wide variety of hydrophilic organic solvents, and the mechanical or chemical stability of the solution is low. Very good. The viscosity of the solution can be freely adjusted depending on the purpose and use by selecting the type of solvent used. By casting the organic solution, a good copolymer film free from defects such as pinholes can be obtained.

The present invention has been developed and completed from the above knowledge,
The polymer film obtained by forming a film from the high concentration organic solution is
This invention is based on the discovery that the above-mentioned difficulties can be overcome in the separation process of liquid mixtures by pervaporation. That is, the present invention provides a liquid mixture having at least an organic liquid as one of its components,
Fluorinated ethylenically unsaturated monomer and carboxylic acid group (-
A film is formed from an organic solution of a fluorinated copolymer containing carboxylic acid groups, in which a copolymer with a polymerizable functional monomer having a COOH group is dissolved in a hydrophilic organic solvent containing a small amount of water. The present invention provides a novel method for separating liquid mixtures, which is characterized by separating liquid mixtures by pervaporation using a polymer membrane obtained by the present invention.

In the present invention, it is important to use a polymerizable monomer having a carboxylic acid group as the functional monomer.

The carboxylic acid type functional monomer (1) is usually desirably a fluorovinyl compound in consideration of the chlorine resistance, oxidation resistance, etc. of the resulting polymer; 〇F2 = CX (OCF20FY), 1
(0)m(CFY') nA (where l is 0 to 3
, m is an integer of θ to 1, n is an integer of 0 to 12, X is a fluorine atom or -CF3-1c-ary, and Y and Y' are a fluorine atom or a perfluoroalkyl group having 1 to 10 carbon atoms.

Further, a fluorovinyl compound represented by (A is -COOH) is exemplified. From the viewpoint of performance and availability, it is preferable that X is a fluorine atom, Y is 10F3, Y' is a fluorine atom, 1 is 0 to 1, m is (1 to 1), and n is 0 to 8. A preferred representative example of such a fluorovinyl compound is CF2=CFO(CF2) 1-8COOH.

CF2=CFO(CF2), 8COOH.

CF2-CF (CF2). ~8C○OH.

CF22C'FOCF2C"F(COF3)○CF2
Examples include CF2COOH.

Next, a fluorinated ethylenically unsaturated monomer (I [l is ethylene tetrafluoride, ethylene trifluoride chloride, propylene hexafluoride, ethylene trifluoride, vinylidene fluoride, vinyl fluoride, etc. Illustrated, preferably, the general formula CF2 "CZZ'
(where z and z' are a fluorine atom, a chlorine atom, a hydrogen atom, or -CF3). Among these, perfluoroolefin compounds are preferred, and tetrafluoroethylene is particularly preferred.

In the present invention, each of the monomer compounds of the functional monomer (11) and the ethylenically unsaturated monomer (Ill) can be used in combination of two or more, and in addition to these compounds, other monomer compounds can also be used. components, e.g. general formula CF2CR4R
5 (herein, R4 and R5 represent a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or an aromatic nucleus)
10] (representing a -fluoroalkyl group), CF22CF-CF20F2, C'
One or more types of divinyl monomers such as F2=CF○(CF2)1-40CF=CF2 and other functional monomers such as sulfonic acid type functional groups can also be used in combination.

Preferred representative examples of the olefin compound (Tsukuda) include ethylene, propylene, butene-1, isobutylene, styrene, α-methylstyrene, peatea-1, and hexene-1.
, heftene-1,3-methyl-butene-1,4-methyl-pentene-1, etc. Among them, ethylene, propylene,
Particular preference is given to using isobutylene and the like.

Further, for example, by using a divinyl monomer in combination, it is possible to crosslink the resulting copolymer and improve the mechanical strength of molded products such as films and membranes.

In the present invention, the carboxylic acid type fluorinated copolymer may be obtained by copolymerization of monomers as described above, but when it is dissolved in a hydrophilic organic solvent in the presence of water, the carboxylic acid type fluorinated copolymer is It is sufficient if the acid group is in the -COOH form. Therefore, as a functional monomer, A is -CN, -COF, -CO
OR, 1-C00M or C0NR2R3 (R1 is an alkyl group having 1 to 10 carbon atoms, R2, R3 is a hydrogen atom or R
1, M is an alkali metal or a quaternary ammonium group) to obtain a copolymer, and the copolymer is subjected to hydrolysis or other treatment to change the carboxylic acid side chain to a -CoOH type axis. You may also adopt one. Further, reduction treatment of fluorinated copolymers having functional groups other than carboxylic acid type, for example, sulfonic acid type functional groups (Japanese Patent Application Laid-Open No. 52-24175.
52-24176.51-24177, etc.), oxidation treatment (JP-A-53-132094.53-13)
The present invention can also be achieved by changing a sulfonic acid type functional group to a carboxylic acid type functional group, and converting this to a -C'OOH form carboxylic acid as necessary. carboxylic acid type fluorine-containing copolymers are available.

In the present invention, from the viewpoint of a highly concentrated organic solution, suitable functional groups in the functional monomer are exemplified as described above.
Of course, the functional groups in the polymer membrane during pervaporation may be converted into an appropriate type. For example, the above A in the polymer membrane may of course be -COOH, but it can also be -〇N, -COF, -COOR+, -CO
It may be O-%, -CONR2R3, etc. Here, R1 is an alkyl group having 1 to 20 carbon atoms, Q is a metal atom such as an alkali metal or alkaline earth metal, or -NR4R
5Re R7, X is the valence number of Q, R2,
R3, R4, Hs, R6 and R7 are hydrogen atoms or R
1 is shown.

Conversion to a functional group that protects is usually carried out after forming a film from a specific organic solution, and it is recommended to select the form of the functional group as appropriate depending on the organic liquid mixture to be subjected to pervaporation. desirable. Moreover, it may be used as a polymer membrane converted to an acid type functional group other than those mentioned above.

In the carboxylic acid type fluorinated copolymer of the present invention, the composition ratios of the functional monomers (11, fluorinated olefin compound (formerly, furthermore, the olefin compound a) and other components are firstly fluorinated It is related to the performance of the copolymer, such as the separation coefficient and permeation amount when made into a polymer membrane, as well as the solubility in hydrophilic organic solvents containing small amounts of water and the stability of the generated organic solution. First of all, the amount of functional monomer (Il) is directly related to the ion exchange capacity and is also related to the stability of the solution;
Variations between 1 and 40 molar, particularly between 1 and 40 molar, are preferred.

In the present invention, it is not always clear why the presence of carboxylic acid type side chains in the 100OH form in the fluorinated copolymer and the presence of water in the organic solvent are related to solubility and solution stability. Not. However, when the carboxylic acid type side chain is in other forms such as the alkyl ester form, it shows almost no solubility, and as mentioned above, even in the -COOH form, it shows almost no solubility in a hydrophilic organic solvent alone without adding water. It is considered that the side chain in the -C○OH form and the added water make some contribution to the solubility in the hydrophilic organic solvent and the stability of the solution. It goes without saying that such explanations are provided to assist in understanding the present invention, and are not intended to limit the present invention in any way.

Therefore, the remainder of the above (11) compounds in the copolymer of the present invention is occupied by other compounds ((It) and furthermore, Tsukuda). It relates to the nature of things. Olefin compounds (til
When Ill is used in combination, the molar ratio of olefin compound side)/fluorinated olefin compound (Ill) is preferably 5.
/95 to 70/30, particularly preferably 10/90 to 60/40. Also, when using fluorovinyl ether or divinyl ether in combination, 3% in the copolymer
It is suitable that the usage ratio is 0 molti or less, preferably about 2 to 20 molti. The concentration of acid-type functional groups in the acid-type fluorinated polymers of the present invention can be employed over a wide range, but in preferred embodiments, the concentration of acid-type functional groups in the acid-type fluorinated polymer may be within a wide range of 0.001 <3 meq/g dry resin at the ion exchange capacity described below. Selected from. The ion exchange capacity is preferably 0.
A value on the order of 1 to 2.2 milliequivalents/gram dry resin is employed. In addition, from the viewpoint of mechanical strength as a polymer membrane, the molecular weight of the acid type fluorinated polymer is preferably 50°C or higher, preferably about 70 to 300°C, when expressed as the TQ value described below. It is.

As used herein, the term "TQ" is defined as follows. That is, TQ is defined as the temperature at which the volumetric flow rate, which is related to the molecular weight of the polymer, is 100 mm3/sec. child,! In , the volumetric flow rate is 30 kg/L: 1n2 under pressure, diameter tmi, length at a constant temperature. The amount of polymer melted and flowed out from a 2m1K Oriswiss is shown in units of 3/sec. Moreover, "ion exchange capacity" was determined as follows. That is, a resin with an acid type functional group in H type such as 1000H is left in IN HCI at 60°C for 5 hours to completely convert to H type, and then water is added to prevent HCI from remaining. Washed thoroughly. After that, this H-type resin 0.5
+! 9, 0. It was left standing at room temperature for 2 days in a solution prepared by adding 25 ml of IN NaOH and 25 ml of K water. Next, the resin was taken out and the amount of Na OHO in the solution was reduced to 0. It is determined by back titration with IN HCI.

As the hydrophilic organic solvent used in the present invention, various examples may be mentioned. Usually, it is desirable to employ a water-soluble organic solvent, and one that dissolves in water at 20° C. by 0.5 weight or more is preferable. Specifically, Ryukoru class,
Examples include ketones, organic acids, aldehydes, and amines. In addition, hydrophilic organic solvents that are easily compatible with water, such as pyrrolidones, esters, and ethers, may also be used even if their solubility in water is not necessarily high, and a mixed solvent system may also be used. Therefore, in the present invention, a small amount of water is added to such a hydrophilic organic solvent. The amount of water added is usually about 0.001 to 30 ttl11, preferably about 0.05 to 20 ttl11, as the concentration in the organic solvent.

When dissolving a specific carboxylic acid type fluorinated copolymer in a solvent, a predetermined amount of the specific fluorinated copolymer is added to the solvent, and if necessary, known dissolution promoting means such as heating and stirring are applied. This is done by giving. The specific fluorinated copolymer used may be in any shape such as a lump, a film, a sheet, a fiber, a rod, or a pellet, but from the viewpoint of promoting dissolution, it is preferably a subdivided product of 20 or more meshes, For example, granules, powders, etc. are preferable. Regarding the temperature during dissolution, a higher temperature is preferable for promoting dissolution, and is usually 20 to 250°C, preferably 30°C.
It is carried out at ~150°C, but l is added to promote dissolution.
It can also be carried out under an increased pressure of -10 atmospheres.

According to the present invention, the concentration of the organic solution can be as high as 40% by weight, but can usually be prepared from 5% to 30% by weight, preferably from 10% to 25% by weight. be. The viscosity of the organic solution can vary from 10 centipoise to 1 million centipoise depending on the concentration of the solution and the type of hydrophilic organic solvent used, but for purposes such as obtaining a good copolymer film by casting etc. Usually 100
It is used in the range of centipoise to 10,000 poise.

When obtaining a film-like material from the specific organic solution by a casting method or the like, various means, operations, conditions, etc. can be employed in a wide range without particular limitation. Accordingly, in the present invention, it is possible to manufacture films ranging in thickness from thin to thick. Furthermore, there are no restrictions on the shape of the film, and even fairly complex film-like products can be manufactured. Usually, a film of the acid type fluorinated polymer can be formed by applying the specific organic solution in the form of a film onto a predetermined mold and volatilizing the hydrophilic organic solvent. A specific acid-type polymer film can be obtained by peeling the formed film-like material from the mold. Of course, if the mold itself can be used for the intended purpose, a film-like material can be integrally formed on the mold and the tile product can be produced as is. For example, a reinforcing porous plate or reinforcing cloth, which will be described later, may be used as a mold, and the surface thereof may be coated with a film-like material or impregnated.

Various means for applying the specific organic solution to the mold may be used, such as casting, coating, and spraying, and roll coating, doctor knife coating, screen printing coating, etc. are also possible. For volatilization of the hydrophilic organic solvent, heating, reduced pressure, etc. may be used as appropriate depending on the type of solvent. In general, it is better to avoid rapid volatilization of the residue as it may cause foaming.

For example, it is preferable to carry out the volatilization operation in consideration of the volatility and boiling point of the hydrophilic organic solvent. It goes without saying that reheating treatment of the formed film may also be used.

In the present invention, polymer membranes containing various porous supports can be employed. Such a polymer membrane can be easily formed by impregnating a porous support with a specific organic solution as described above and drying it. As a porous support,
Conventionally known reinforcing supports such as ion exchange membranes can be appropriately employed.

For example, materials such as fluorine-based resins such as polytetrafluoroethylene, asbestos, metals, glass fibers, etc., and shapes such as woven fabrics, nets, non-woven fabrics, perforated plates, porous sheets, and even arbitrary shapes, For example, it may be sheet-like, cylindrical, or other complicated shape. The impregnation means, volatilization of the hydrophilic organic solvent, drying, etc. are the same as in the above-mentioned casting method.

Furthermore, in the present invention, various composite membranes,
A structure in the form of a laminated film or the like may also be adopted. For example, there may be mentioned a composite membrane in which various conventionally known or well-known ion exchange membranes are used as a base material, and a coating film made from the above-mentioned specific organic solution is formed on the surface of the base material. A strong composite membrane has the advantage that it is possible to freely change the ion exchange capacity or the type of functional group between the base material and the coating film. For example, if the ion exchange capacity is larger on the coating side than on the base material side, the coating side has weak acidic functional groups such as carboxylic acid groups, and the base material side has strong acidic functional groups such as sulfonic acid groups. It is possible to create a composite membrane with

The polymer film formed from the specific organic solution of the acid type fluorinated polymer of the present invention is a non-porous uniform film, and the film thickness is about 1 to 250 microns, preferably about 5 to 180 microns. Adopted.

If the film thickness becomes too thin, the film will lack strength or durability. Furthermore, if the membrane is too thick, the amount of permeation of the liquid mixture becomes small, making it impractical. The shape of the polymer membrane is usually a flat membrane, but it can also be used in other shapes such as a cylindrical shape or a hollow fiber shape to increase the surface area. Furthermore, various reinforcing means may be applied, such as embedding a reinforcing material such as a cloth in the membrane, or laminating the membrane on a porous reinforcing body.

The method of the present invention is carried out using an apparatus partitioned into a primary chamber and a secondary chamber by an acidic polymer membrane as described above. - The next chamber contains the organic liquid mixture to be separated or concentrated in liquid form, while the secondary chamber is reduced in pressure in a suitable manner or circulated with other liquids or gases. In this way, the organic liquid mixture is permeated through the polymer membrane to create a barbeque...
Separate or concentrate using - The liquid inside the next chamber is preferably circulated externally or internally, or - agitated by providing a suitable stirring device inside the next chamber. It is advantageous in terms of durability if the specific polymer membrane is held in an appropriate manner so as to partition the primary chamber and the secondary chamber, or supported by, for example, a perforated reinforcing plate. - Substances that permeate the polymer membrane from the next chamber are taken out from the second chamber and collected.

It is usually desirable to appropriately heat the secondary chamber and/or the secondary chamber using a suitable heating device, such as a heating jacket.

The separation method of the present invention is carried out over a wide range of temperatures, typically from 0 to 20-0°C, preferably from room temperature to 100°C.
Selected from a range of approximately ℃.

If the temperature is too high, problems will arise in maintaining the shape of the polymer membrane, and if the temperature is too low, the amount of liquid permeated will be small. Generally, the amount of permeation can be increased at high temperatures, but the concentration ratio (separation coefficient) due to membrane permeation becomes smaller. In addition, the pressure range that can be adopted is usually from vacuum to 100 kg/cIrL.
2. Preferably, the pressure is from vacuum to about 30 kli'/cm2, and if the pressure is too high, it becomes difficult to maintain the shape of the polymer membrane.

The organic liquid mixtures that can be separated by the method of the present invention include various combinations, such as mixtures of organic substances that cannot be separated by normal distillation methods because of the presence of azeotropic points, and mixtures of organic substances that cannot be separated by ordinary distillation methods because their boiling points are close to each other. This method is particularly effective in the case of mixtures of organic substances that are difficult to separate by distillation. Further, the organic liquid mixture may be entirely dissolved in each other uniformly, or a part of the organic liquid mixture may exceed the solubility and precipitate into a suspended state.

However, the organic liquid mixture needs to be in a liquid state in its mixed state within the above-mentioned implementation temperature range and at normal pressure or within the adopted pressure range.

Examples of organic liquid mixtures that have an azeotropic point include benzene/cyclohexane and benzene/n.
- Mixtures of organic substances such as hexane, methanol/acetone, benzene/methanol, acetone/chloroform; water/isoglopanol, water/ethanol, water/n
7' O/: /～ru, water/allyl alcohol, water/2
-methoxyethanol, water/isobutanol, water/n-
Water/alcohol mixtures such as butanol, water/2-butanol, water/furfuryl alcohol, water/n-pentanol, water/2-pentanol, water/4-methyl-1-butanol; water/tetrahydrofuran, water/ Examples include dioxane and water/organic solvent mixtures such as water/methyl ethyl ketone.

In addition, as mixtures whose boiling points are close to each other, ethylbenzene/styrene, p-chloroethylbenzene/p
-Chlorstyrene, toluene/methylcyclohexane,
Examples include butadiene/butenes, butadiene/butanes, n-butene/1-butene, and the like. Other examples include water/glycerin, water/glycols, water/propylene chlorohydrin, water/propylene dichlorohydrin, water/epichlorohydrin, water/hydrazine, and isomer mixtures.

Furthermore, the method of the present invention can be applied to these mixtures not only in the above two-component systems but also in multi-component systems, such as ternary or more. Of course, the method of the invention can also be applied to mixtures containing organic and inorganic substances, such as wastewater containing organic liquids.

The mixing ratio of the liquid mixture to be treated can be changed within an arbitrary range, but in general, the closer the ratio is to the equivalent situation, the higher the concentration ratio will be. If the desired purity cannot be obtained by passing through a polymer membrane once (-membrane concentration), pass it through a similar device multiple times (multi-stage concentration).
It is also possible to concentrate or separate the organic liquid mixture to the desired degree.

Examples of the present invention will be described in more detail below, but it goes without saying that the present invention is not limited to the above description.

Example I C2F4 and CF2 = CFO(CF2)3 C00C
The copolymer obtained by bulk polymerizing Hs with diisopropyl peroxydicarbonate as an initiator at 40°C at 6-7 kg/cm'' was hydrolyzed to obtain an ion exchange capacity of 192 milliequivalents/g of the carboxylic acid of the polymer. A type copolymer was obtained. To the polymer 20.9, 2 g of water and 1789 acetone were added.
was added and stirred at room temperature for 16 hours, resulting in a homogeneous and transparent solution with a concentration of 10% by weight and a viscosity of 500 centipoise. A good film with a thickness of 30 μm was obtained by casting the solution at 30° C.

The film was hydrolyzed with caustic soda, treated with pure water at 90°C for 16 hours, and then dried at 70°C for 24 hours. Using the obtained film, a mixture of water and impropatuol was prepared using de-papering. (Improper Tools/Water=s 2/
1 s, weight ratio) was separated. At a temperature of 40°C, a pressure of 10-' on the permeate side, and 1 Hg, the separation coefficient of water for Improper Tool was 9.7, and the amount of permeation was 213.
011/m2・hr.

Example 2 C2F4 and CF22CF○(C'F'2)a COOC
H3 to C8F, CCX) NH.

Using NH4) 28208 as a surfactant and an initiator, the copolymer obtained by emulsion polymerization at 57°C and 11 kg/cm2 was hydrolyzed to give an ion exchange capacity of 1.45 meq/cm2.
An acid type copolymer of g was obtained. 4 g of water to 20 g of the copolymer,
By adding 76 g of acetone and stirring for 40 hours, a slightly cloudy solution with a concentration of 20% by weight and a viscosity of 9000 centipoise was obtained. A good film with a thickness of 30 μm was obtained by casting the solution at 60° C.

After the film was hydrolyzed in caustic soda, the functional groups were changed to --COOH type in hydrochloric acid, treated with 90':c in pure water for 16 hours, and dried at 70 DEG C. for 24 hours. M Jli
A mixture of water and ethanol (ethanol/water 94/6, weight ratio) was separated by pervaporation. The separation coefficient of the water obtained at 40°C, 1o-1mm) (g) with respect to ethanol was 4.91, and the permeation amount was 248°, 9/m2·hr.

Procedural amendment written in April 1980, Haruki Shimada, Commissioner of the Patent Office1, Indication of the case, Patent Application No. 185527, filed in 19832, Name of the invention, Method for separating liquid mixtures3, Person making the amendment, Connection with the case Related Patent applicant address: 2-1-2 Marunouchi, Chiyoda-ku, Tokyo Name (
004) Asahi Glass Co., Ltd. Second Okada Building 6, Number of inventions increased by amendment None 7, Subject of amendment Specification

Claims (1)

[Scope of Claims] 1. A liquid mixture containing at least an organic liquid as one of its constituents is made of a fluorinated ethylenically unsaturated monomer and a polymerizable functional group having a carboxylic acid group (-C'OOH group). A polymer film obtained by forming a film from an organic solution of a fluorinated copolymer containing a carboxylic acid group, in which the copolymer with a monomer is dissolved in a hydrophilic organic solvent containing a small amount of water, is used. hand,
A method for separating a liquid mixture, characterized by separation by pervaporation. 2. The separation method according to claim 1, wherein the concentration of water in the hydrophilic organic solvent is 0.001 to 30% by weight.