JPS5889901A - Method for separating liquid mixture - Google Patents

Abstract

PURPOSE:To enhance efficiency of separating a mixture of organic liquid through pervaporation, by using a polymer membrane made by forming a copolymer of a fluorinated ethylenically unsatd. monomer and a functional monomer having an acid type functional group into a film through a specified procedure. CONSTITUTION:A monomer having an acid type functional group, such as carboxylic, sulfonic, or phosphonic group, and a fluorinated ethylenically unsatd. monomer, such as tetrafluorethylene, trifluorochloroethylene, or hexafluoropropylene, are polymerized in an aq. medium at 7-50kg/cm<2> pressure by irradiation of radioactive rays or use of a polymerization initiator. The obtained aq. dispersion is substituted by an aq. org. solvent, such as alcohol, ketone, org. acid, aldehyde, or amine, and a porous support is impregnated with this dispersion, and dried, thus permitting an org. liquid mixture to be separated with high separation coefft. and permeation rate by pervaporation using the obtained membrane.

Description

Detailed Description of the Invention The present invention provides a liquid mixture containing at least an organic liquid as one of its constituent components (hereinafter abbreviated as an organic liquid mixture).
It relates to a method for separating or concentrating by pervaporation using a specific polymer membrane.

A process for separating organic liquid mixtures using non-porous, uniform polymeric membranes has been previously described in U.S. Pat.
This is taught in Specification No. 2, etc. This separation process is generally called a pervaporation process using a membrane, in which the liquid to be treated is supplied to the primary side (high pressure side) of the polymer membrane, and substances that are easily permeable are removed from the secondary side (the high pressure side). This is a method of preferentially transmitting it as vapor to the low-pressure side. This membrane separation method can separate liquid mixtures that could not be separated using conventional simple methods.
For example, it is attracting attention as a new method for separating or concentrating azeotropic mixtures, mixtures with close boiling points and low specific volatility, and mixtures containing substances that polymerize or modify when heated.

Conventionally, polymer membranes used in such separation methods include poly-11 ethylene, poly-1] cellulose-based polymer substances, polyacrylonitrile, polyamide, polyester, and polystyrene.

Membranes made of polytetrafluoroethylene or copolymers thereof are known. However, when such a membrane is used to separate an organic liquid mixture by pervaporation, the following practical difficulties are recognized. That is, (1) Since the rate of concentration (separation coefficient "All") caused by an organic liquid mixture passing through a polymer membrane once is small, in order to concentrate or separate it to the desired concentration, it is necessary to pass through a very large number of The separation factor must be passed through a membrane.In general, the separation factor is as follows.

αAB = Senken (2) Since the amount of permeation of an organic liquid mixture through a polymer membrane (generally expressed as per unit membrane surface area, unit membrane thickness, and permeation cover per unit time) is small, the membrane surface area can be very large. Or, the thickness of the polymer membrane must be made extremely thin. Therefore, in the former case, the cost of equipment and equipment will be excessive.Therefore, as the above-mentioned improved process, a method using a polymer membrane in which sulfonic acid groups etc. are bonded to a polymer substrate, a method using a specific polyamide membrane, etc. Methods using ionomer polymer membranes, methods using ionomer polymer membranes, etc. are disclosed in JP-A-52-111888, JP-A-52-111889, JP-A-54-43278, JP-A-54-55279, etc. .

The present inventor has conducted various studies and studies regarding means for separating or concentrating various organic liquid mixtures by pervaporation, and as a result, has obtained the following interesting findings. That is, acid type fluorinated polymers having acid type functional groups such as carboxylic acid groups, sulfonic acid groups, and phosphonic acid groups can be produced as a highly concentrated aqueous dispersion by emulsion polymerization in an aqueous medium. Yes, it is possible to replace the aqueous medium of such an aqueous dispersion with a hydrophilic organic solvent such as an alcohol. Although the reason is not necessarily clear, the dispersion state is not destroyed even when replaced with a hydrophilic organic solvent, and a non-aqueous dispersion liquid that maintains a stable dispersion state can be obtained. Furthermore, the non-aqueous dispersion thus obtained can be applied to film formation in the same way as an organic solvent solution. For example, an aqueous latex of a hecarponic acid type or sulfonic acid type fluorinated polymer can be separated into an aqueous medium layer and a latex layer with an increased polymer concentration by an appropriate centrifugation operation.
Possibly, by adding a hydrophilic organic solvent to the concentrated latex layer and repeating the centrifugation operation, the aqueous medium content in the concentrated latex layer is reduced and replacement by the hydrophilic organic solvent is achieved. The acid type fluorinated polymer is dispersed in a hydrophilic organic solvent while maintaining the dispersion state of an aqueous latex.

By such substitution treatment, a non-aqueous dispersion can be obtained which maintains a polymer concentration similar to that in the aqueous latex. See Japanese Patent Application No. 54-149479 and Japanese Patent Application No. 54-157989.

The present invention has been developed and completed from the above knowledge,
The fact that a film-like material can be smoothly and advantageously formed from the non-aqueous dispersion by a casting method, and the polymer film thus obtained can overcome the above-mentioned difficulties in the separation process of liquid mixtures by pervaporation. It is based on the discovery of

That is, the present invention involves polymerizing a liquid mixture containing at least an organic liquid as one of its components with a fluorinated ethylenically unsaturated monomer and a polymerizable functional monomer having an acid type functional group. Copolymerization is carried out in an aqueous medium by the action of an initiating source to obtain an aqueous dispersion containing the acidic fluorinated polymer having a functional monomer content of 0.1 to 50 molt in a dispersed state; A non-aqueous dispersion of an acid type fluorinated polymer is obtained by replacing the aqueous medium of the aqueous dispersion with a hydrophilic organic solvent without destroying the dispersion state, and a film is formed from the non-aqueous dispersion. The present invention provides a novel method for separating liquid mixtures, which is characterized by separation by pervaporation using a molecular membrane.

In the present invention, it is important to use a non-aqueous dispersion of a specific acidic fluorinated polymer.

According to the specific replacement processing means of the present invention,
Non-aqueous dispersions with high concentrations of about 50% by weight can be easily obtained using a wide variety of hydrophilic organic solvents, and the mechanical and specific gravity stability of the dispersions is extremely good. The viscosity of the dispersion can be adjusted freely depending on the purpose and application by selecting the type of solvent used.One thing is that by casting the non-aqueous dispersion, it is possible to obtain a good quality product without defects such as pinholes. A copolymer film can be obtained smoothly and advantageously.

In the present invention, as the functional monomer, a carboxylic acid group,
It is important to use polymerizable monomers containing sulfonic acid groups, phosphonic acid groups, or acid type functional groups convertible to these groups. The acid type functional monomer (1) is usually preferably a fluorovinyl compound,
Preferably, the general formula cp, = CX −(c
t;'x'), - is exemplified by a fluorovinyl compound. Here, p is 0 to 1.1 is 0 to 3. m is 0~
1. n is an integer from 0 to 12, X is a fluorine atom, a chlorine atom, or -CF3, and X is a fluorine atom or -CF
3, Y is a fluorine atom or -CF, and Y' is a fluorine atom or a fluoroalkyl group having 1 to 10 carbon atoms. Still A is -CN.

-〇〇F, -C00H1-C00R1, -C00, 10M
.

-cozeE', -5caF, to -s, +M, 5o3H
.

is an acid type functional group, ba is an alkyl group having 1 to 20 carbon atoms, M is a metal atom such as an alkali metal or alkaline earth metal, or -Nt is bi, χ is the valence number of M, and g ,
*, t, R:', and represent hydrogen atoms or W. From the viewpoint of performance and availability, X is a fluorine atom and Y is 10F3. Y' is a fluorine atom, p is 0, 1 is 0
~19m is O~1゜n is 0~8, and A is -coore, -5o2p, or - due to copolymerization reactivity etc.
i: (OR)2, and lv is preferably a lower alkyl group. Preferred representative examples of such fluorovinyl compounds include: CF2=CFCF2: CFO(CF2), ~8C'00C2)(x
.

CF2=CF(CF'ri.~, c('X')C'I-4
゜CF2= C)'0CF2CF (OCF, ) 0
CF2C1;', on C■C1.

CF2=cvccv:cF(CF, )ocp,c
tr, so, p.

CF2=CFS02F, CF2=CFCF20CF2C
F2SqF.

1 CF, = CF'0(CF2), ~a P(QC"
H,,)2.

1 CF2=CFO(CF2), ~8P(QC,)%,)2
Examples include ゜.

In the present invention, from the viewpoint of copolymerization reaction in an aqueous medium, the above-mentioned suitable functional groups are exemplified as -, acid, and type functional monomers. The acid-type functional groups in the molecular film can be appropriately selected depending on the organic liquid mixture, etc. Then, after forming the polymer film, the functional groups can be converted to an appropriate type. For example, , a sulfonic acid type functional group was disclosed in JP-A-52
-24175. 52-241'76゜5-2-24
Reduction processing 5 such as No. 177, or JP-A-51-
152094. It can be converted into a carboxylic acid type functional group by oxidation treatment such as that in Publication No. 55-152069,
Furthermore, conversion of functional groups may be carried out in a similar manner at the monomer stage. Functional group transformations are selected to best suit each step.

Next, as the fluorinated ethylenically unsaturated monomer (II), ethylene tetrafluoride, ethylene trifluoride chloride, propylene hexafluoride, ethylene trifluoride, vinylidene fluoride, vinyl fluoride, etc. Illustrated and preferred general formula CF2=CZZ
It is a fluorinated olefin compound represented by (C, Z, 'Zi = fluorine atom, chlorine atom, hydrogen atom, or 1-CF3). Among these, perfluoroolefin compounds are preferred, and tetrafluoroethylene is particularly preferred.

In the present invention, two or more types of each monomer compound of the functional monomer (1) and the ethylenically unsaturated monomer (It) can be used, and in addition to these compounds, Other components, for example, an olefin compound 111 represented by the general formula CJ4=C1 (where -R5 represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or an aromatic nucleus)
D, fluorovinyl ether such as CF2=CFORf (I (f represents a perfluoroalkyl group having 1 to 10 carbon atoms), CF2=CF-CF'=CF2.CI', 2αη(CF2)1-40CF=CF Divinyl monomers such as !, furthermore, carboxylic acid type functional monomers can be used in combination with one or more other sulfonic acid type functional monomers. Preferred representative of olefin compound (2) Examples include ethylene, propylene, butene-1,
Imbutylene, styrene.

Examples include α-methylstyrene, pentene-1, hexene-1, heptene-1,3-methyl-butene-1゜4-methyl-pentene-1, among others, due to manufacturing reasons and the performance of the resulting copolymer. Particularly preferred are ethylene, propylene, 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 acid-type fluorinated polymer of the present invention, the composition ratios of the functional monomer (1), the fluorinated olefin compound (n), and the olefin compound Cll0 and other components are determined firstly. This is important because it relates to coalescence performance, etc., and also to the stability of the dispersion state during substitution treatment with a hydrophilic organic solvent from an aqueous dispersion to a non-aqueous dispersion. The amount of the functional monomer (1) is directly related to the ion exchange capacity and also to the stability of the dispersed state.
The amount in the copolymer is preferably from 0.1 to 50 mol, particularly from 1 to 40 mol.

In the present invention, the reason why the presence of acid type side chains in the fluorinated polymer is related to the stability of the dispersion state is not necessarily clear. However, during centrifugal separation of aqueous dispersions, acid-type fluorinated polymers containing acid-type functional groups such as carboxylic acid groups and sulfonic acid groups cannot be maintained in a stable dispersion state in the concentrated latex layer. On the other hand, with fluorinated polymers that do not have functional groups such as carboxylic acid groups or sulfonic acid groups, latex destruction is observed at the same level of concentration.
It is thought that the acid type side chain makes some contribution to the stability of the dispersed state. It goes without saying that such explanations are provided to assist in understanding the present invention and do not limit the present invention in any way.

Therefore, the remainder of the above (+) compound in the copolymer of the present invention is occupied by the above (n) and further (II [l) and other compounds, but It is related to the mechanical properties of the case.Olefin compounds (1
! When D is used in combination, the molar ratio of olefin compound II)/fluorinated olefin compound (n) is preferably 5/95 to 70/30, particularly 10/9'0 to 60/4.
It is preferable that it be over 0. However, even when fluorovinyl ether, divinyl ether, etc. are used in combination, it is preferable to use the copolymer in a proportion of 30 mol or less, preferably about 2 to 20 mol.

The concentration of acid-type functional groups in the acid-type fluorinated polymer of the present invention can be adopted over a wide range, but in a preferred embodiment, the concentration of acid-type functional groups in the acid-type fluorinated polymer is 0.01 to 3 milliequivalents per ion exchange capacity as described below.
Selected from a wide range of gram dry resins. The ion exchange capacity is preferably about 0.1 to 2.2 milliequivalents/g dry resin for 11. In addition, from the viewpoint of mechanical strength as a polymer membrane, the molecular weight of the acid type fluorinated polymer is preferably 5°C or more, preferably about 70 to 300 tll' when expressed as the TQ value described below. It is.

In the unspecified text, the term "TQ" is defined as follows. That is, the volumetric flow rate, which is related to the molecular weight of the polymer, is 100. The temperature in J/sec is defined as TQ. child\
The volumetric flow rate in the polymer is -CO
Using a methyl ester type like OCH3,
The polymer was heated at a constant temperature, with a diameter of 1fi and a length of 2, under a pressure of 30mm.
The amount of polymer melted and flowed out from the orifice of fi is expressed in units of 1/sec. Moreover, "ion exchange capacity" was determined as follows. That is,
A resin in which the acid type functional group is a 1-1 type such as -cOa1,
6 Or in HCl IN.

The mixture was left to stand for 5 hours, completely converted to type 11, and thoroughly washed with water so that no I2C1 remained. Thereafter, 0.52 of this H-type resin was left standing at room temperature for 2 days in a solution prepared by adding 25 of water to 0.1N NaαI25. Next, the resin is taken out and the amount of Nao) in the solution is determined by back titration with 0.1N HCl.

In the present invention, in the copolymerization reaction between the functional monomer and the fluorinated olefin compound, the amount of aqueous medium used is preferably 20/1 or less in the weight ratio of aqueous medium/functional monomer. It is preferable to control the ratio to 10/1 or less. If too much aqueous medium is used, the copolymerization reaction rate will be significantly reduced, and if too much is used, it will be difficult to achieve a high molecular weight when using a high ion-exchange capacity to obtain a high copolymer yield. It becomes difficult. Furthermore, the use of a large amount of an aqueous medium poses the following difficulties. For example, there are disadvantages in operational aspects such as an increase in the size of the reactor and separation and recovery of the copolymer.

Next, in the present invention, 7Kg/an? It is preferable to employ the above copolymerization reaction pressure. If the copolymerization reaction pressure is too low, the copolymerization reaction rate cannot be maintained at a level that is practically satisfactory, and there are also difficulties in forming a high molecular weight copolymer. Furthermore, if the copolymerization reaction pressure is too low, the ion exchange capacity of the resulting copolymer will become extremely high. In addition, the copolymerization reaction pressure is desirably selected from 50 υ or less, taking into consideration the reaction apparatus or work operation in industrial implementation. Although it is possible to employ a copolymerization reaction pressure higher than this range, it is not possible to proportionately improve the objects of the present invention. Therefore, in the present invention, the copolymerization reaction pressure is 7 to 50 mm, preferably 9 to 50 mm.
It is best to select from the range of 0\i.

In the copolymerization reaction of the present invention, conditions and operations other than the above-mentioned reaction conditions are not particularly limited and may be adopted over a wide range. For example, the copolymerization reaction temperature can be arbitrarily selected depending on the type of polymerization initiation source, reaction molar ratio, etc., but usually, too high or too low a temperature is disadvantageous for industrial implementation. 90C1 preferably 60-80
O selected from approximately r. Therefore, in the present invention, it is desirable to select a polymerization initiation source that exhibits high activity at the above-mentioned suitable reaction temperature. For example, it is possible to use highly active ionizing radiation even below room temperature, but it is usually more advantageous for industrial implementation to use an azo compound or a no-oxy compound. Polymerization initiation sources suitably employed in the present invention include dicono-phosphoric acid peroxide, pen/silver oxide, lauroyl-no-chlorine oxide, and dipenta phosphate peroxide, which exhibits high activity at about 20 to 90 C under the copolymerization reaction conditions. Diacyl peroxides such as fluoroprobionyl monooxide, 2,2'-azobis(2-amidinopropane) hydrochloride, 4°4'-azobis(4-cyanowalleric acid), azobisisobutyronitrile, etc. azo compounds, peroxy esters such as -butyl peroxy isobutyrate and t-butyl peroxy pivalate, peroxy dicarbonates such as diisopropyl peroxy dicarbonate, di-2-propyl hexyl peroxy dicarbonate, Hydroperoxides such as diisoprobyl benzene hydroperoxide, potassium persulfate.

These include inorganic peroxides such as ammonium persulfate and their redox systems.

In the present invention, the concentration of the polymerization initiator is 0.0001 to 3% by weight, preferably 0.001 to 2% by weight based on the total monomers.
It is about % by weight. By lowering the initiator concentration,
It is possible to increase the molecular weight of the resulting copolymer, and it is possible to obtain a polymer that retains a high ion exchange capacity. If the initiator concentration is too high, the tendency to decrease the molecular weight increases, which is disadvantageous to the production of high ion exchange capacity, high molecular weight copolymers.

In addition, surfactants 9 dispersants, buffers, pH adjusters, etc. used in ordinary aqueous medium polymerization can also be added. In addition, as long as it does not inhibit the copolymerization reaction between the fluorinated olefin compound and the specific functional monomer and has little chain transfer, for example, fluorinated solvents known as fluorocarbon solvents or fluorinated chlorine may be used. Inert organic solvents such as saturated hydrocarbons can also be added.

Therefore, in the copolymerization in an aqueous medium in the present invention, it is preferable to control the concentration of the produced copolymer to 40% by weight or less, preferably 60% by weight or less. If the concentration is too high, problems such as increased stirring load, difficulty in heat removal, and insufficient diffusion of the fluorinated olefin monoar are observed. 'In the present invention, the aqueous dispersion obtained as described above is subjected to a substitution treatment with a hydrophilic organic solvent. As for the replacement treatment means, as long as the dispersion state of the aqueous dispersion is not destroyed, a combination of separating the aqueous medium layer by various methods and adding a hydrophilic organic solvent, separating the aqueous medium layer by an electric tilting method or a freezing method. Examples include a combination of adding a hydrophilic organic solvent and a hydrophilic organic solvent, or a method of removing water overnight after adding a hydrophilic organic solvent having a boiling point higher than that of water. Usually, it is effective to gradually separate the aqueous medium layer by repeating the steps of separating the aqueous medium layer by centrifugation, adding a hydrophilic organic solvent to the concentrated layer, and subjecting this to centrifugation. ° Can be adopted.

As the hydrophilic organic solvent used in the displacement treatment in the present invention, there are various examples. Usually, it is desirable to employ a water-soluble organic solvent for the purpose of smoothly and advantageously displacing and separating the aqueous medium. Preferably, those that dissolve in water in an amount of 0.5% by weight or more. Specifically, alcohol,
Examples include ketones, organic acids, aldehydes, and amines. In addition, hydrophilic organic solvents that are easily compatible with water even if their solubility in water is not necessarily high, such as pyro-11 tons and esters.

Ethers may also be used, and a mixed solvent system may also be used.

In the operation of adding a hydrophilic organic solvent to the concentrated layer to replace the aqueous medium layer, it is sufficient to repeat the operation depending on the tolerance of water remaining in the non-aqueous dispersion, and usually several times is sufficient. It is. There is no particular limitation on the amount of organic solvent to be added, but it is usually 0.5 to 2% by weight of the polymer.
0 parts by weight.

In the present invention, the concentration of the non-aqueous dispersion can be as high as 60% by weight, but it is usually 5% to 50% by weight.
, preferably in a concentration of 10% to 40% by weight. The viscosity of the non-aqueous dispersion varies from 1.0 centipoise to 1 centipoise depending on the concentration of the dispersion and the type of hydrophilic organic solvent used.
Although it can vary up to 1,000,000 centipoise, it is usually 1,000 centipoise for the purpose of obtaining a good copolymer film in the present invention.
It is used in the range of 00 centipoise to 10,000 voise.

When obtaining a film-like material from the non-aqueous dispersion by a casting method or the like, various means, operating conditions, etc. can be employed over a wide range without particular limitation. According to the present invention, it is possible to manufacture films ranging in thickness from thin to thick, and there is no limit to 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 non-aqueous dispersion in a film on a predetermined mold and volatilizing the hydrophilic organic solvent. By peeling the formed film-like material from the mold, a specific acid-type polymer film can be obtained. Of course, if the mold itself can be used for the purpose as it is, it is also possible to integrally form a film-like material on the mold and use it as a product. This is the case when a mold is used as a mold and a film-like substance is coated on the surface of the mold, or the surface is coated with an impregnated coating.

Casting is also a means of applying a non-aqueous dispersion onto a mold.

Various methods are used, including 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,
Too rapid volatilization may cause foaming, so it is better to avoid it.

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.

A polymer membrane can be easily formed by impregnating a porous support with a non-aqueous dispersion as described above and drying it. As the porous support, those conventionally known or well-known as reinforcing supports such as ion exchange membranes can be appropriately employed.

For example, in terms of materials, fluorine-based resins such as polytetrafluoroethylene, asbestos 1. Metals, glass fibers, etc., as well as woven fabrics, mesh materials, non-woven fabrics, perforated plates, porous sheets, and even arbitrary shapes are acceptable. Impregnation means, volatilization of hydrophilic organic solvents, drying, etc. This is 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 from the above-mentioned non-aqueous dispersion is formed on the surface of the base material. Such a 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, the ion exchange capacity on the coating side may be larger than that on the substrate side, or the coating side may have weakly acidic functional groups such as carboxylic acid groups, and the substrate side may have strong acidic functional groups such as sulfonic acid groups. It is possible to make it into a composite membrane.

The polymer film formed from the non-aqueous dispersion 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 bill contains the organic liquid mixture to be separated or concentrated in liquid form, while the two bills are subjected to reduced pressure in a suitable manner or circulated with other liquids or gases. In this way, the organic liquid mixture is permeated through a polymer membrane and separated or concentrated by pervaporation. - The liquid inside the primary chamber can be circulated externally or internally, or - An appropriate stirring device is installed inside the membrane. It is preferable to use a filter to stir or cool the mixture. The specific polymer membrane is held in a suitable manner to partition the primary chamber and the secondary chamber, but it is advantageous in terms of durability if it is supported by, for example, a perforated reinforcing plate. - Substances that have passed through the polymer membrane from the bill are taken out from the secondary chamber and collected.
. It is usually desirable to appropriately heat the bill 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, usually from 0 to 200C, preferably from room temperature to 100C.
Selected from a range of degrees.

If the temperature is too high, there will be a problem 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. Further, the usable pressure range is usually vacuum to 100 yen, preferably vacuum to 30 t8 degrees, 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. However, all of the organic liquid mixture may be uniformly dissolved in each other, 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 employed pressure range.

Examples of such organic liquid mixtures include benzene/cyclohexane and benzene/n as mixtures having an azeotropic point.
- Mixtures of organic substances with each other such as hexane, methanol/acetone, benzene/methanol, acetone/chloroform; water/isoph: lopanol, water/ethanol, water/
n-furopanol, water/allyl alcohol, water/2-methoxyethanol, water/isobutanol.

Water/n-butanol, water/2-butanol/-/l'l water/furfuryl alcohol, water/n-pentanol, water/2
- Water/alcohol mixtures such as pentanol, water/4-methyl-1-butanol; water/tetrahydrofuran,
Examples include water/organic solvent mixtures such as water/dixane and water/methyl ethyl ketone.

In addition, as mixtures whose boiling points are close to each other, ethylbenzene/styrene, p-chloroethylpenze//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. The method of the present invention can be applied not only to a two-component system as described above, but also to a multi-component system of three or more components. 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 a homogeneous mixture, 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).
, the organic liquid mixture can also be concentrated or separated to a desired extent.

Examples of the present invention will be described in more detail below, but it goes without saying that the present invention is not limited by such explanations.

Example 1 1 portion of ion-exchanged water was placed in a 0.2 t stainless steel pressure-resistant reaction vessel.
002, ξF, 7COONI (, 0.2f.

Na21(PO4,12HQO 0.59.Na)(
PQ, 2H20 0.52, (NH4)28208
to, 026y charge, then 2Of CF2
-CFO(CF2)3αCH3 was charged. After sufficiently degassing with liquid nitrogen, the temperature was raised to 57C, and tetrafluoroethylene was introduced to a temperature of 11.0 to cause a reaction. During the reaction, tetrafluoroethylene was continuously introduced into the system and the pressure was increased to 11
．． It was kept at 0￥i. After 4.5 hours, unreacted tetrafluoroethylene was purged to terminate the reaction. Furthermore, unreacted CF2
: CPO(CF2)s C00CH, trichlorotrifluoroethane was added and extracted and separated to obtain a stable aqueous dispersion having a concentration of 19 wt. CF2= in copolymer
The composition of CFO(CF, )s C0OH, is 20.3
It was morchi. The aqueous dispersion was separated into an aqueous medium and a polymer concentrated layer using a centrifuge. Remove the aqueous medium layer, add the same amount of new water, and repeat the centrifugation operation.

The electrolyte used in the polymerization was removed by repeating the edging six times. Next, 152 of a mixed solvent of N-methylpyrrolidone and methanol (N-methylpyrrolidone/methanol = 2.5/1 weight ratio) was added to the concentrated layer to form a dispersion, and the centrifugation operation was repeated again. Finally, an organic solvent having the above composition was added to the concentrated layer again to produce a non-aqueous dispersion having a copolymer concentration of 20% by weight. The viscosity of the dispersion was 1000 centipoise.

The dispersion was cast onto a thoroughly washed glass plate and heated at 50C.
By leaving the film in an electric furnace for 10 hours, a film with a thickness of 60 μm was obtained.

The film was hydrolyzed with caustic soda, treated in pure water at 90C for 16 hours, and then dried at 70C for 24 hours to obtain a membrane with an ion exchange rating of 1.4' 3 +neq/9. A mixture of water and Impropanol (Isopropanol/Water-82/1B-1
weight ratio) was separated. Temperature 40C1 Permeate side pressure 1. o
The minute m coefficient for isopropanol of water obtained at arm Hg is 1.82, and the permeation amount is 1530 f
/m”, hr.

Example 2 A non-aqueous dispersion having a copolymer concentration of 35% by weight was produced by carrying out the same procedure except for changing the mixed solvent of methylpyrrolidone and methanol to propatool. The viscosity of the dispersion was 250 centivoise, and 50 tZ' on the glass plate.
A good film with a thickness of 50 μm was obtained by leaving it for 20 hours at 0.0 The film was hydrolyzed in caustic soda, the functional group was changed to the 1αηI] type in hydrochloric acid, and the film was treated with pure water at 90C for 16 hours. , 70 tl' for 24 hours. A mixed solution of water and ethanol (ethanol/water = 94/69 weight ratio) was separated by pervaporation using a loading/unloading device. 40
C910rra.

The separation coefficient of water obtained in Hg to ethanol is 5.05, and the permeation rate is 1930 f/m'.

He was talented.

Example 6 In Example 1, CF2=CFO(CF2)s co
αM.

Tsukawarini CF2 = CFOCF2CFO (CF2), c
OOC) (Polymerization was carried out in the same manner except that 3 was charged with CF3 and the reaction was carried out at a polymerization pressure of 13υ, and Cl12=CFOCF2CFO (C)).

A 19% by weight aqueous dispersion of a copolymer of C00CII3CF3 having a composition of 16.0 mol was obtained. The electrolyte was desalted from the aqueous dispersion using an ion exchange resin, 1002 diethylene glycol monomethyl ether was added to the aqueous dispersion, and water was evaporated using a rotary evaporator. This operation was repeated three times while adding diethylene glycol monomethyl ether, and finally the diethylene glycol monomethyl ether was concentrated to obtain a stable non-aqueous dispersion having a copolymer concentration of 30% by weight and a viscosity of 380 centipoise. By leaving the non-aqueous dispersion on a glass plate at 100C for 5 hours, a thickness of 2
A good film of 0μ was obtained.

The film was hydrolyzed in lithium hydroxide and diluted with pure water at 9%
0. After being treated with C for 16 hours, it was dried at 70C for 24 hours to obtain a film with -αηIji type functional groups. As a result of conducting a separation experiment similar to Example 2 using loading and unloading, the separation coefficient and permeation amount were 5.92. 2230 f/
It was m', hr.

Example 4 CF2=CpOCF2CF(CF3)OCF20F2S
An aqueous dispersion obtained by emulsion polymerization of 02F and tetrafluoroethylene was subjected to the same operation as in Example 1 to obtain a non-aqueous dispersion of a copolymer with an ion exchange capacity of 0.85 meq7j at a concentration of 20% by weight. Manufactured. The viscosity of the non-aqueous dispersion is 120
It was 0 centipoise. 5 from the dispersion by a casting method.
A film with a thickness of 30 μm was obtained at 0C for 10 hours.

The film was hydrolyzed with caustic soda, treated in pure water at 90C for 16 hours, and then dried at 70C for 24 hours to obtain a membrane with an ion exchange capacity of 0.85 meq/l. A mixed solution of water and ethanol (ethanol/water = 94/6. weight ratio) was separated by pervaporation using a loading/unloading method. The separation coefficient of water for ethanol obtained in 40C110-'waa, lIg is 941, and the permeation amount is 2600t/W? , it was hr.

Procedural amendment form) August 2, 1980 Haruki Shimada, Commissioner of the Patent Office1, Indication of the case 1986 Patent Application No. 1868272, Name of the invention Method for separating liquid mixtures 3, Person making the amendment Case and Relationship Patent applicant address 2-1-2 Marunouchi, Chiyoda-ku, Tokyo Name (
004) Asahi Glass Co., Ltd. 6. Number of inventions increased by amendment None 7. Subject of amendment Specification

Claims (1)

[Claims] A liquid mixture containing at least an organic liquid as one of its components is mixed with a fluorinated ethylenically unsaturated monomer and a polymerizable functional monomer having an acid type functional group in an aqueous medium by the action of a polymerization initiator. to obtain an aqueous dispersion containing the acid type fluorinated polymer having a functional monomer content of 0.1 to 50 mol in a dispersed state, and to destroy the dispersion state of the aqueous dispersion. Instead, the aqueous medium of the aqueous dispersion is replaced with a hydrophilic organic solvent to obtain a non-aqueous dispersion of the acid type fluorinated polymer, and a polymer film obtained by forming a film from the non-aqueous dispersion is used. , a method for separating a liquid mixture characterized by separation by pervaporation.