JPS5892415A - Separation of liquid mixture - Google Patents

Abstract

PURPOSE:To enhance separation efficiency, in separating an org. liquid mixture by pervaporization, by using a high molecular membrane obtained by forming a porous layer with gas or liquid permeability on the surface of a high molecular membrane. CONSTITUTION:A binder, a thickening agent and a conductive extender are appropriately added to a metal or metal oxide, metal hydroxide, metal carbide, metal nitride or a mixture thereof and a fine powder of an org. polymer and, after all components are mixed in an appropriate medium, the resulting mixture is supplied on a filter to obtain a porous cake layer by a filtering method. This porous cake layer is adhered on the surface of a high molecular membrane or a paste formed from the aforementioned mixture is coated thereon by a screen printing method, a plasma spraying method, a transfer method or a roll coating method to form a porous layer and this porous layer is subsequently heated under pressure to obtain a composite membrane. This composite membrane is used as a separation membrane to carry out the separation or the concn. of an org. liquid mixture by pervaporization.

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 has been previously described in U.S. Pat. No. 2,953,500.
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 supplied to the secondary side (low pressure side). This is a method of preferentially transmitting it as vapor. This membrane separation method can separate or separate liquid mixtures that could not be separated by conventional simple methods, such as co-liquid mixtures, mixtures with close boiling points and low specific volatility, and mixtures containing substances that polymerize or denature when heated. It is attracting attention as a new method of decontamination.

Conventionally, polymer membranes used in such separation methods include polyethylene, polypropylene, cellulose-based polymers, polyacrylonitrile, polyamide, polyester, polystyrene, polytetrafluoroethylene, or copolymers thereof. membrane is known. However, when separating a wet liquid mixture by pervaporation using a membrane, the following practical difficulties are recognized. That is, (1) Since the rate of concentration (separation coefficient α) caused by the organic liquid mixture passing through the interlayer membrane once is small, a very large number of membranes are required to concentrate or separate the organic liquid mixture to the desired concentration. must be passed. Generally, the separation coefficient αAB is as follows.

(2) Transmission t of an organic liquid mixture passing through a polymer membrane
(generally expressed as unit membrane surface area, unit membrane thickness, and permeation amount per unit time) is small, so the membrane surface area is made very large, but the thickness of the polymer membrane must be made extremely thin. Therefore, the cost of equipment and equipment for the former fund would be higher than that of the prefectural university, and the latter would have problems with the strength and durability of the membrane.

Six improved processes have been proposed, including a method using a polymer membrane with sulfonic acid groups bonded to a polymer base, a method using a specific polyamide membrane, and a method using an ionomer polymer membrane. It is disclosed in Publication No. 52-111888, Publication No. 52-111889, Publication No. 54-33278, Publication No. 54-33279, etc.4'.

The present inventor has conducted various studies on means for separating or concentrating various organic liquid mixtures by pervaporation.
As a result of repeated studies, the following findings were obtained. That is, by forming a gas- and liquid-permeable porous layer on the surface of a polymer membrane such as an ion exchange membrane and performing pervaporation using the polymer membrane, the above-mentioned difficulties can be solved smoothly and advantageously. I discovered that. For example, the porous layer may serve as a reinforcing means for the polymer membrane, and has the effect of increasing the affinity with the liquid mixture and further promoting evaporation on the secondary side.

A porous layer can help increase the evaporation surface area.

Thus, the present invention has been completed based on the above findings, and provides a method for preparing a liquid mixture containing at least an organic liquid as one of its constituents, in which a gas and liquid permeable porous layer is formed on at least one side of the liquid mixture. The present invention provides a novel method for separating liquid mixtures, which is characterized by separation by pervaporation using a polymer membrane.

In the present invention, the gas- and liquid-permeable porous layer formed on the polymer membrane surface can be composed of various materials. That is, it may be a conductive material or a non-conductive material (B), and may be formed from either an inorganic material or an organic material. Usually, it is preferable to use a material that is resistant to the target organic liquid mixture and its constituent liquids and gases.

For example, a wide range of examples may include metals, metal oxides, hydroxides, carbides, nitrides, or mixtures thereof, as well as organic polymers. To give a specific example, group ■-A of the periodic table (preferably germanium, tin,
lead), IV-B group (preferably titanium, zirconium,
Hafnium'), V-B group metals (preferably niobium, tantalum), iron group metals (iron, cobalt, nickel), etc. alone or alloys, oxides, hydroxides, nitrides, or carbides are resistant to various liquids. It is exemplified as an excellent example. Others include silver, stainless steel, carbon, silica, alumina,
Alternatively, polymers such as tetrafluoroethylene resins and polyolefins, and tetrafluoroethylene resins treated to make them hydrophilic with potassium titanate or the like may also be used.

In forming the specific porous layer, the above material preferably has a particle size of 0.01 to 300μ, particularly 0.1 to 100μ.
used in powder form. At this time, if necessary, a binder such as a fluorocarbon polymer such as pholytetrafluoroethylene or polychlorotrifluoroethylene, and
Thickeners such as celluloses such as carboxymethyl cellulose, methyl cellulose, and hydroxyethyl cellulose, water-soluble substances such as polyethylene glycol, polyvinyl alcohol, polyvinyl pyrrolidone, sodium polyacrylate, polymethyl vinyl ether, casein, and polyacrylamide are used. These binders or thickeners are preferably 0 to 50% by weight based on the powder,
In particular, it is used in an amount of 05 to 3ON. At this time, if necessary, an appropriate surfactant such as a long-chain hydrocarbon or a fluorinated hydrocarbon, and another conductive filler such as graphite may be added to facilitate the formation of a porous layer. be able to. In any case, the content of particles forming the porous layer in the formed porous layer is 0.001 to 50 t/cr
It is preferable to set ls'lj to 0.01 to 30 W/*.

Formation of a specific porous layer from the above materials is described in Japanese Patent Application Laid-Open No. 54-1
12398, or by thoroughly mixing the above powder, a binder, a thickener, etc. used as necessary, in an appropriate medium, and then applying it onto a filter by a filtration method. Either a porous layer cake is obtained and the cake is attached to the membrane surface, or the above mixture is made into a paste and this is applied directly to the polymer membrane surface by screen printing or the like.

The porous layer formed on the surface of the polymer membrane is then preferably formed using a press molding machine, preferably at a temperature of 80 to 220
It is heated and pressed onto the membrane surface at 1-150 kg/- at a temperature of 1 to 150 kg/-, preferably partially embedded in the membrane surface. Thus, the porous layer formed on the membrane surface preferably has a porosity of 10 to 9.
9 inches, especially 25 to 95 inches, and the thickness is preferably 0.01 to 200μ, especially 0.1 to 10μ.
It is appropriate to set it to 0μ. Further, the average pore diameter is preferably 0.01 to 200μ.

In the present invention, various polymer membranes that have been conventionally used in paper papers may be used without particular limitation. Preferably, ion exchange membranes having various functional groups are employed, and the following polymer membranes made of fluorine-containing ion exchange resins are particularly preferred. Such a fluorine-containing ion exchange resin is preferably a resin made of a functional fluorine-containing polymer that completely blocks ion exchange groups such as carboxylic acid groups, sulfonic acid groups, phosphoric acid groups, and phenolic groups. Examples of such resins include those having a copolymer structure of vinyl monomers such as tetrafluoroethylene and chlorotrifluoroethylene, and fluorovinyl monomers containing ion exchange groups such as sulfonic acid, carbonic acid, and phosphoric acid groups. preferable.

In particular, it is preferable to use polymers having the following structures (a) and (b).

\Y where X is F, 61. H or -07g, and X'
ke
Fz-CF←A.

X X 1 7x+7+z
are both θ~10, and Z and Rf are selected from -Flld perfluoroalkyl groups having 1 to 1 o carbon atoms. Also, A is 100 OF! .

-Coo・7M, -8○s Hr -8Oa ”t
M, etc., or -802F, -ON, which can be converted to these groups by hydrolysis.

-C! OF, "-COOR", -8OaR", -
〇〇NR"R3, -8O2It is an acid type functional group such as NR"R", M is a metal atom such as an alkali metal or alkaline earth metal, or -NRRRR, t is the valence number of M, and R1 is an alkyl group having 1 to 2 carbon atoms, and R2゜R3, R4
, R6, R@ and R7 represent a hydrogen atom or R1.

Therefore, in the present invention, a fluorine-containing ion exchange resin (
(hereinafter abbreviated as acid-type fluororesin) is composed of a fluorinated ethylenically unsaturated single digit body (1) and an acid-type functional monomer (It).
It can be a copolymer with

Examples of (1) include tetrafluoroethylene, chlorotrifluoroethylene, propylene hexafluoride, ethylene trifluoride, vinylidene fluoride, and vinyl fluoride, with the general formula C! F2=C! It is a fluorinated olefin compound represented by XX' (X and X' are as defined above).

Among these, perfluoroolefin compounds are preferred, and tetrafluoroethylene is particularly preferred. (II) is preferably a fluorovinyl compound of the general formula 〇Fz=(J:Y (X and Y are as described above), and a preferable example is CF+=CX-(OOF2 C!FRf' )p-(OJ
CL-(CFR/f)r-A (where p is o~3,
q is an integer of θ~1, r is an integer of θ~12, and X, Rf, A
is as described above, and the arch is Rf). From the viewpoint of performance and availability, it is preferable that X is a fluorine atom, Rf is 10Fa, RI is a fluorine atom, p is 0-1, q is O-1, and r is 0-8. Fluorovinyl compound (It
) is a preferable representative example of CF 2 =CFO(C
! F2) t～a OOOR”, CF z=O
FO(CF2) 1~8 C0FCF2=CF (
C! F2). ~、C! OOR'.

0F2=CFOCF20F (CF's) O(!F
2CF2C! OOR”.

C1Fz=CFOCFzCF(CFs)OCFzOF2
00F'.

CF2=OFO(CF2), ~8SO2F.

CFz=OFOOF20F (OFm) QC! Fz
Examples include OFg 5OzF.

In addition, in the present invention, functional groups other than carboxylic acid type,
For example, reduction treatment of fluorinated copolymers having sulfonic acid type functional groups (JP-A No. 52-24175, No. 52-2417)
6, JP-A No. 52-24177, etc.), oxidation treatment (see JP-A-53-132094, JP-A No. 53-132069, etc.) to convert the sulfonic acid type functional group to a carboxylic acid type functional group. Polymers may be used as specific acid fluororesins. Of course, the carboxylic acid type can be converted to the sulfonic acid type, or the monomer can be converted to the carboxylic acid type or sulfonic acid type by similar treatment at the monomer stage, and the acid type functional monobutyrate ( It may also be used as II).

Furthermore, in the present invention, the above-mentioned (1), (It), (a), or (a) is used as a structural unit of the specific acid type fluororesin.
(b) can be used in combination of two or more, and in addition to these, other components such as olefin compounds such as ethylene, propylene, and isobutylene, CF
2=CFOQ, a fluorovinyl ether such as (Q represents a perfluoroalkyl group having 1 to 10 carbon atoms), C
Fs-0F-CF=CF2゜CFz=CFO(CFz
) 1~400F=C! Dihinyl monomers such as Fz,
Others can also be used singly or in combination of two or more.

The ion exchange capacity of the specific polymer membrane of the present invention can be varied over a wide range as described below, but since the ion exchange resin membrane is In the case of a specific fluorine-containing ion-exchange resin membrane made of a polymer, the polymerized unit (b) is preferably about 0.1 to 50 moles, particularly about 1 to 40 moles.

In the present invention, the content of the acid type functional group in the acid type fluororesin can be adopted over a wide range, and is selected from a wide range of 0.01 to 3 milliequivalents/g dry resin in terms of ion exchange capacity.

The ion exchange capacity is preferably about 0.1 to 2.2 mE: l': /g dry resin. In addition, from the viewpoint of mechanical strength as a polymer membrane, the molecular weight of a specific acid type fluororesin is 5 when expressed by the TQ value described below.
The temperature is preferably 0°C or higher, preferably about 70 to 300°C.

In this specification, the term rI'QJ is defined as follows. That is, the temperature at which a volume flow rate of 100 gJ/sec, which is related to the molecular weight of the polymer, is defined as TQ. In and \, the volumetric flow rate was determined by using a polymer with an acid type functional group of methyl ester type such as -C○0CHs group, and applying the polymer under a pressure of 30 kg/ah.
1m diameter at constant temperature.

The amount of polymer melted and flowed out from an orifice with a length of 2 mm is shown in units of -7 seconds. In addition, "ion exchange capacity" was determined as follows. That is, a specific acid-type fluororesin whose acid-type functional group is H-type, such as 1000H, is left in IN HOI at 60°C for 5 hours, completely converted to H-type, and HOI remains. Wash thoroughly with water to prevent stains. After that, this H-type resin 052 was converted into O]N Na
It was left standing at room temperature for 2 days in a solution prepared by adding 25 mt of water to 25 mt of OH. Next, the resin was taken out and the amount of NaOH in the solution was reduced to 0. It is determined by back titration using the HOI of IN.

In the present invention, a polymer film is formed by the above-mentioned acid-type fluororesin force or other suitable means.

The polymer membrane thus obtained does not necessarily need to be formed from one type of polymer, nor does it need to have only one type of acid type functional group.

For example, two types of polymers may be used in combination for the ion exchange capacity, or a polymer membrane may be used in combination with a weakly acidic functional group such as a carboxylic acid group and a strongly acidic functional group such as a sulfonic acid group. . For film formation, various conventionally known methods can be employed. In addition, the specific polymer membrane may be preferably made of cloth, net, or other fabrics made of a fluorine-containing polymer such as polytetrafluoroethylene, non-fertile cloth,
Alternatively, it can be reinforced with metal mesh, porous material, etc.

In the present invention, when heating and melting is involved during the above-mentioned manufacturing or formation of a specific porous layer, the fluorine-containing ion exchange resin is treated with an appropriate material that does not cause decomposition of the ion exchange groups it has. When the ion exchange group is a carboxylic acid group, it is preferably an acid or ester type, and when a sulfonic acid group is used, it is preferably an 18O2F type.

In the present invention, a specific porous layer is formed on at least one side of the polymer membrane as described above. The specific porous layer will be explained in more detail. First, the materials constituting the porous layer can be used over a wide range of materials as described above. That is, molten metal oxides (e.g., molten titanium oxide, zirconium oxide,
tin oxide, niobium oxide, chromium oxide, etc.), conductive metals (valve metals, iron group metals, scissors, stainless steel, etc.), inorganic solid electrolytes (for example, Na5ZrzSizPO□2.
Na5bOa, Na5YSi4012, KzS
b*Ot1. Li14ZnG1340111, etc.),
Non-oxide ceramics (for example, carbides, nitrides, silicides, borides, sulfides, etc.), fluororesins, polyamide resins, polyamide resins, polyphenylene oxide resins, polyphenylene sulfide resins, polypropylene resins, etc. are also included in addition to the above-mentioned examples. , can be exemplified as a constituent material of the porous layer. Such constituent materials are used not only in powder or granular form, but also in the form of a porous thin layer such as carbon vapor, cloth of various resins, and nonwoven fabric. Furthermore, it may be in the form of fine fibers or may be composed of fine particles of alkali metal titanate. In addition, as the constituent material of the porous layer, ion exchange resins such as acid-type fluororesins, which are the constituent materials of the above-mentioned polymer membrane, can also be used, and fluorine-containing monomers having various acid-type functional groups, CaFs, CzC
Modified polytetrafluoroethylene obtained by copolymerizing a small amount of IFa, perfluorovinyl ether, etc. may also be used. Of course, the porous layer may be formed by using two or more of the above-mentioned materials in combination, such as a combination of an inorganic material and an organic material, a combination of a granular material and a fibrous material, or a combination of a conductive material and a non-conductive material. may be used in combination as appropriate.

The constituent materials of the specific porous layer as described above are bonded to the surface of the polymer membrane as a porous layer by various means. For example, a porous thin layer may be prepared in advance as described above and applied to the surface of the polymer membrane, and the constituent material may be used as a paste or various dispersions by screen printing, spraying, transfer, or roll coating. - It may be formed by coating by a method or the like. In addition, in the case of screen printing, transfer method, etc., the porous layer can be formed in various patterns such as a lattice shape or polka dot shape, or it can be formed as a dense porous layer such as in a flat coating. Furthermore, particles or particle groups made of the material constituting the porous layer may be bonded to the surface of the polymer membrane independently of other particles or particle groups to form a porous layer as a whole.

The porous layer forming means will be explained in more detail.

As the screen printing method, various known and well-known methods are employed, but the screen used in the present invention preferably has a mesh size of 10 to 2400, particularly 1
A thickness of 50 to 1,000 mesh is suitable, and a thickness of preferably 4 to 2 mm, particularly 8 to 300 microns. If the mesh number is too large, the screen will become clogged, resulting in uneven printing; if the mesh number is too small, excessive paste will be deposited. On the other hand, if the thickness is too large, the printing will be uneven, and if the thickness is too small, the printing will be uneven.
I am unable to print a fixed quantity. A screen mask is cut into strips in order to provide a porous layer of an appropriate size and shape on the surface of the polymer membrane, but the shape is formed by cutting out the shape of the electrode layer to be formed on the membrane surface. Usually, the thickness is preferably from 3 to 500 μm to 1 μm. The material of the screen and screen mask should have sufficient strength, for example, polyurethane, stainless steel, tetron, nylon 7, etc.
Mataha x.

Boxy resin is used.

A screen with a screen mask attached is installed on the polymer membrane on which the porous layer is formed, and the paste-like material is supplied onto the screen and printed while applying pressure with a squeegee. A porous layer having a shape excluding the screen mask is formed on the surface of the polymer membrane.

The thickness of the porous layer on the polymer membrane surface is the thickness of the screen,
It depends on the paste viscosity and the mesh number of the screen. The thickness of the porous layer is preferably 1 to 50
It is preferable to adjust the screen thickness, paste viscosity, screen mesh number, etc. so that the thickness is 0μ, particularly 1 to 300μ.

Furthermore, the distance between the screen plate and the polymer membrane during screen printing, the material of the squeegee, and the applied pressure of the squeegee are also related to the physical properties, thickness, and uniformity of the porous layer formed on the surface of the polymer membrane, so In order to obtain a predetermined value, for example, the distance between the screen plate and the polymer film is set to a predetermined distance depending on the type and viscosity of the paste. Furthermore, it is preferable that the squeegee has straight edges, that the hardness and material match the paste viscosity, and that the applied pressure of the squeegee is constant.

The viscosity of the paste is determined by screen printing.
Preferably O, 1 to 1011 voids, especially H 1.0 to 1
It is 41 off to control to about 0.04 poise.

Alternatively, a thermal spraying method may be employed in which particles of the constituent material of the porous layer are sprayed while being melted, or a dispersion, a paste, or the like containing the particles as described above may be sprayed. As the porous layer-constituting particles produced by the injection method, an aqueous suspension containing the porous layer-constituting particles and modified polytetrafluoroethylene as a binder is applied to the surface of a polymer membrane placed on a hot plate at about 100°C. , a method of spraying the water using a spray can and drying the water can be suitably employed.

Next, a transfer method is exemplified as a means for forming the porous layer. A preferred embodiment of the transfer method includes a method in which a paste-like material as described above is applied onto a base film such as a plastic film, and the paste is transferred onto the surface of a polymer film. The base film is not particularly limited as long as it has a smooth surface and a certain degree of heat resistance, and a wide range of materials can be employed. Considering the transfer process in which the polymer film is layered and heated, the thickness of plastic films such as saturated polyester resin, polyamide resin, polycarbonate resin, high-density polyethylene, polypropylene, cellulose acetate, polyimide resin, and fluororesin is in the range of 12 to 2000μ. Preferably. Of course, a metal film such as aluminum foil may also be employed as the base film.

Various methods can be used to apply the coating to the base film, such as spray painting, brush painting, and screen printing. In that case, a general-purpose coating method such as an air knife coater, a blade coater, a rod coater, a knife coater, a reverse roll coater, a cracker roll coater, a kiss coater, a calendar coater, a nip coater, or a dip coater is preferable. Either is fine.

By using such a coating method, the solid content concentration of the paste is controlled, and the above-mentioned o, o
Apply so that the solid content of t adheres to one side of the base film. After coating, the evaporable solvent is evaporated at room temperature or by heating to form a porous layer on the base film.

For forming a porous layer on a base film, it is preferable to use a paste-like material such as the one described above. It is also possible to form a porous layer by adhesion coating using an electric powder coating method, a fluidized dip coating method, or the like.

Next, the porous layer formed on the base film as described above is transferred onto the surface of the polymer membrane.

That is, by stacking the base film on one or both sides of the polymer membrane via the porous layered wide surface and applying heat and pressure, the porous layer is formed from the base film side to the polymer layer side. The porous layer is partially embedded in the diurnal membrane surface. The pressing temperature in this case is selected from a wide range of conditions under which the film softens or melts, and is usually selected from a range of about 100 to 300"C. In addition, the press pressure is 1000 to 1,000 ℃ per child in the case of a flat plate press. CWn% preferably 1-20
In the case of a roll press using a pair of rolls, a roll length of 0.5 to 200 kg/7 cm, preferably 1 to 100 kg/crn-roll length is adopted.

It can also be used as a means of forming a porous layer.Roll coating method desirable from the viewpoint of

In this case, the coater includes a rod coater, blade coater, knife coater, air knife coater,
Any general-purpose coating method such as a reverse roll coater, clavia roll coater, kiss coater, calendar coater, nip coater, or tip coater can be employed. Normally, a paste-like material such as the one described above is uniformly applied to the surface of the polymer membrane, and then the evaporated components in the paste-like material are continuously dried in a drying oven.
Formation of porous layers is possible. After forming a porous layer on one side of the polymer membrane by roll coating, if it is long, roll it up and then apply roll coating to the back side in the same way to form the polymer membrane. It is also possible to form porous layers on both sides.

The amount of solid particles attached after application and drying depends on the solid content concentration of the paste, the viscosity, the conveyance speed of the polymer film to be applied,
It can be controlled by the rotational speed of each roll, or in the case of a single bar coater, the distance between the backup roll and the bar coater. In the case of a gravure coater, etc., it can also be controlled by an engraved pattern on the gravure roll. In any case, the amount of paste applied is 0001 to 50/6I11 in terms of particle solid content.
It is desirable to apply the coating to a predetermined thickness as uniformly as possible, preferably within the range of 0.01 to 309/7.

The applied paste can be dried at a temperature within a range that does not cause thermal deterioration of the polymer film, for example, 320° C. or lower,
The temperature, time, etc. can be selected and carried out depending on the bath string I5 in the paste-like material.

In this way, a porous layer with uniform thickness and high adhesion is formed on one or both surfaces of the polymer membrane, but it is preferable to press the porous layer against the membrane surface under pressure as necessary. is preferred. Such pressing methods include the flat plate pressing method, in which the coated film is cut into predetermined dimensions and then pressed between heated flat plates, and the rolled film is pressed between a pair of heated rolls, especially a metal roll and a rubber roll. Any roll press method that presses continuously while rotating can be adopted. In this case, the pressing temperature can range from about 100 to 300[deg.] C. under a wide range of warming conditions, such that the film becomes cold and melts. The press pressure is 4/1 to 1000 in the case of a flat plate press.
d, preferably about 1-2ooKg/d, in case of roll press O65-200Kg/cm-roll length,
Preferably, about 1 to 100 Kg/cnz-roll length is adopted.

Furthermore, in the present invention, the following method may also be adopted as a means for forming the porous layer. That is, the method of embedding and bonding the material particles constituting the porous layer in the membrane surface as described above is not sufficient, but the method of bonding and holding the porous layer material to the membrane surface with a coating made of various film formation 4&□T resins. It is. In this case, there are various examples of the film, including the above-mentioned organic solution of acid type fluororesin (for example, Japanese Patent Publication No. 48-13333,
JP-A-54-107949, - JP-A-55-=149
336) or those formed from non-aqueous dispersions are suitable. In particular, JP-A-56-7
Films made from non-aqueous dispersions described in JP-A No. 2022 and JP-A-56-81342 are preferably employed.

The polymer itself forming the porous layer used in the present invention is a non-porous homogeneous material, and its I! ＃Thickness is 1-3
00 microns, preferably about 5 to 250 microns. If the film thickness is 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-like material in the membrane, or laminating the membrane on a porous reinforcing body.

The method of the present invention uses a polymer membrane in which the above-mentioned porous layer is formed,
- It is carried out using a device that is divided into a secondary and a secondary chamber. - the next chamber contains the organic liquid mixture to be separated or concentrated in liquid form; - the gunfire chamber is evacuated in a suitable manner or other liquids or gases are circulated; In this way, the organic liquid mixture is permeated through the polymer membrane and separated or concentrated by pervaporation.

−The liquid inside the next chamber can be removed or circulated internally, −
It is preferable to provide a suitable stirring device inside the next chamber for stirring. 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 permeate the polymer membrane from the next chamber are taken out from the second chamber and collected. and usually a suitable heating device, e.g.
It is desirable to appropriately heat the secondary chamber and/or the secondary chamber by using a heating jacket or the like.

The separation method of the present invention is carried out over a wide range of temperatures, typically from 0 to 200°C, preferably from room temperature to 100°C.
Selected from a range of degrees.

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/dl,
Preferably, the pressure is from vacuum to about 30 kg/cli; 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, in its mixed state, needs to be liquid within the above-mentioned operating temperature range and at normal pressure or within the adopted pressure* range.

Examples of such liquid mixtures include benzene/cyclohexane and benzene/n as mixtures having an azeotropic point.
- Mixtures of organic substances such as hexane, methanol/acetone, benzene/methanol, acetone/chloroform; water/isopropanol, water/ethanol, water/
n-propertool, water/allyl alcohol, water/2-methoxyethanol, water/isobutanol, water/n-butanol, water/2-butanol, water/furfuryl alcohol, water/n-pentanol, water /2-pentanol,
Water/alcohol mixtures such as water/4-methyl-1-butanol; water/tetrahydrofuran, water/dioxane,
Examples include water/organic solvent mixtures such as water/methyl ethyl ketone.

However, as mixtures whose boiling points are close to each other, TE, 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 even if they are not two-component scales as described above, but multi-component systems 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 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).
, 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 73 d of tin oxide powder with a particle size of 44 μm or less was suspended in water, and polytetrafluoroethylene (pTy) was added to this.
g) Add the suspension so that PTFK is 7.3111y, add a nonionic surfactant (Rohm and Haas,
After dropping (trade name: TRITON

The thin layer has a thickness of 30μ, a porosity of 75%, and an air permeability coefficient of 3.
．． It had 8 x 10 mol/6 Il-CrrIHg and contained 5/- of tin difluoride.

On the other hand, by the same method as above, nickel oxide of 44 μ or less was contained, 7 my/cr/l was formed, the thickness was 35 μ, and the porosity was 73.
H, air permeability coefficient 3.5×10 mol/crI・mi
! A thin layer of r −cm Hg was obtained.

Next, each thin layer was coated with an ion exchange capacity of t45me.
q/f, thickness 200μ, and a copolymer of tetrafluoroethylene and 0F2==OFO(CF2)8coocI(3). Laminated, temperature 160℃,
The porous PTFK film was applied to the surface of the polymer membrane by applying pressure at 60 Kp/cd, and then the porous PTFK film was removed, and porous thin layers of tin oxide and nickel oxide were adhered to each surface. A polymer membrane was obtained.

The film was hydrolyzed with caustic soda, and then heated to 90°C in pure water.
After processing for 6 hours, it was dried at 70°C for 24 hours. Using the obtained membrane, a mixture of water and isopropanol (impropanol/water = s 2
/1B, weight ratio) were separated. At a temperature of 40°C and a pressure on the permeate side of 10 tmHg, the separation coefficient of the obtained water for isopropanol was 19.6, and the permeation amount was 340 f/m''.

Example 2 In Example 1, instead of the porous tin oxide thin layer, a thickness of 28μ, a porosity of 78%, and an air permeability coefficient of 4.0×10
A polymer membrane was prepared in the same manner except that a porous thin layer containing hardened titanium 59/d having physical properties of mol/d-i-crnHg was used.

After the membrane was hydrolyzed in caustic soda, it was converted into a q-cooH functional group in salt water, treated in pure water at 90°C for 16 hours, and then dried at 70°C for 24 hours. A mixed solution of water and ethanol (ethanol/water = 94/6. weight ratio) was separated by pervaporation using the membrane. 4
The number of separators for ethanol in water obtained by heating at 0° C. and 10 w Hg Ic was 5.23, and the amount of permeation was 5602/silence/maru.

Procedural amendment defense form) April 1980 Commissioner of the Japan Patent Office Haruki Shimada1, Indication of the case Patent Application No. 190703 filed in 19822, Name of the invention Method for separating liquid mixtures 3, Person making the amendment Related Patent applicant address: 2-1-2 Marunouchi, Chiyoda-ku, Tokyo Name (
004) Asahi Glass Co., Ltd. 4, Agent 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 membrane separated by pervaporation using a gas- and liquid-permeable porous layer or a polymer membrane formed on at least one side of the porous layer. A method for separating liquid mixtures.