JPS5889909A - Method for separating liquid mixture - Google Patents

Abstract

PURPOSE:To execute efficient pervaporation operation in separating or concentrating an org. liquid mixture, by using a membrane of a ternary copolymer of fluorinated olefin type monomers. CONSTITUTION:A mixture of org. liquids or water and an org. liquid is separated or concentrated by pervaporation, and a membrane used is made of a ternary copolymer of fluorinated olefin, carboxylic acid type fluorovinyl ether, and fluorovinyl ether monomers, and it has 0.01-3m.equiv./g, thus permitting efficiency and rate of separation or concentration to be enhanced in pervaportion operation. Suitable operation temp. and pressure are 0-200 deg.C and 0-100kg/cm<2>, respectively, and usable membrane thickness is 1-250mum. The membrane may be laminated on a porous support.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for producing a one-temperature 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. It relates to a method of separation or concentration.

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.The liquid to be treated is supplied to the primary side (high pressure side) of the polymer membrane, and the easily permeable substance is transferred to the secondary side (low pressure side). This is a method of preferentially transmitting it as vapor. This membrane separation method is
It is attracting attention as a new method for separating or concentrating liquid mixtures that could not be separated by conventional simple methods, such as azeotropic mixtures, mixtures with close boiling points and low specific volatility, and mixtures containing substances that polymerize or modify when heated. ing.

Conventionally, the polymer membranes used in such separation methods include BORIEL-SENSHIN, BORIPS-Pyrene, SENO-LP-based polymer substances, polyacrylonitrile, polyamide, Holiesdel, 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.

In other words, since the concentration ratio (separation coefficient αAB) of an organic liquid mixture when it passes through a polymer membrane once is small, it must pass through a very large number of membranes in order to concentrate or separate it to the desired concentration. 3. In general,
The separation factor 6AI is as follows.

(2) The amount of permeation of an organic liquid mixture through a polymer membrane (generally expressed as the permeation amount per unit membrane surface area, unit membrane thickness, and unit time) is small, so the membrane surface area is made very large. The thickness of the polymer membrane must be made extremely thin. Therefore.

In the former case, equipment costs will be excessive.

In the latter case, problems arise in the strength and durability of the membrane.

As the above-mentioned improved process, there are a method using a polymer membrane in which a snophonic acid group or the like is bonded to a polymer base, a method using a specific polyamide membrane, a method using an ionomer polymer membrane, etc. JP 52-111888, JP 52-111889, JP 54-33278
This method is disclosed in Japanese Patent Publication No. 54-55279, 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 studies, we found that a fluorinated olefin compound such as tetrafluoroethylene, a fluorinated vinyl compound having a carbonic acid type functional group, and a specific
It has been found that a polymer membrane made of a copolymer with r---Theno-L compound can overcome the above-mentioned difficulties.

In the present invention, a liquid mixture having at least an organic liquid as one of its constituent components is prepared by combining a fluorinated olefin compound (+) with the general formula % (X is a fluorine atom or -CF, Y and Y' is a fluorine atom or a fluoroalkyl group having 1 to 10 carbon atoms, l is 0 to 5, m is 0 to 1, n is 1 to 12, and A is -COOH, -COF, -CN .

-COOR', -Coo-iM or -CONR'R"
One of the Q.

R1 is an alkyl group having 1 to 20 carbon atoms 1M is a metal atom or -NR'R''R@R', X is the valence number of M and C is R8
, B & , 14, RA , RA and R' are hydrogen atom = child sentence is R゛σ is as described above and s Rt is a perfluoroalkyl group having 1 to 12 carbon atoms). The present invention provides a novel method for separating liquid mixtures using a polymer membrane of ~6 milliequivalents/g dry resin and separating by -t4 by pervaporation.

The polymer membrane in the present invention is as described above (1), @
and a copolymer of four. First, the above-mentioned fluorovinyl compound has the general formula CF, 2CX-(
OCF, CFY), -(o)m-(CFY')ll-A
It is expressed as Here, xs Ys ” * l
%m*n and A are the same as above, but from the point of view of performance and availability, X is a fluorine atom, Y is -cr,
, y' is -F %l is 0-1, m is O-1
, 11 is 0 to 8 and 1ha again. A is particularly preferably -COF or -COOR' from the viewpoint of ease of copolymerization. mosquito(
Preferred representative examples of fluorovinyl compounds include C
F, =CFO(CF, ). ~,coocus.

CF, 2 CFO (CF,). ~8COF.

CF, -cvocr, cr (cr,) OCF, CF, C
00CH,.

CF, 2CFOCF, CF, (CF,)OCF, εF,
C.O.F.

CF, -, CF- (CF, ). -,coocu,
.

Examples include.

Moreover, the fluorovinyl ether compound (2) is.

As above [, general formula CF, =CX-(OCF, CF
Y), -OR.

Here, X, Y, l and Rf are the same as above, but the use of such a fluorovinyl ether compound and the nature of R2 therein are one of the factors in the durability of the above-mentioned membrane, From this point of view, Rt is particularly preferably a perfluoroalkyl group having 3 to 6 carbon atoms. Preferred specific examples of such fluorovinyl ether compounds include perfluoro-propyl vinyl ether, perfluorobutyl-3,6-thioxer-4-methyl-7-octene, and the like.

On the other hand, the fluorinated olefin compound (T) is preferably represented by the following general formula.

cr,=czz where z and z' are -F, -CI, -H or -CF.

Preferred typical examples thereof include tetrafluoroethylene, trifluorochloroethylene, hexafluoropropylene, trifluoroethylene, vinylidene heptafluoride, and hinyl fluoride, among which /(-fluoro compound are preferred, and tetrafluoroethylene is particularly preferred.

Incidentally, A in the specific polymer membrane of the present invention is selected as described above from the viewpoint of σ2 such as copolymerization reactivity, but it can also be selected as appropriate depending on the organic liquid mixture to be pervaporated.

For example, it is possible to convert the functional groups into an appropriate form after forming a polymer film. Examples of M include metal atoms such as alkali metals and alkaline earth metals, or -NR'R''HmBl.

In the present invention, two or more of the above compounds are used as a constituent unit of a fluorine-containing copolymer having a specific carboxylic acid type functional group (hereinafter abbreviated as carbonic acid type fluororesin). In addition to these, other components such as olefin compounds such as egg ash, propylene, and isobutylene, CF, =CF-CF-CF,
,CF,=cro(CFs),~40CF=CF,
It is also possible to use divinyl monomers such as ζ and one or more other functional monomers having a sulfonic acid type functional group. Combined with divinyl monomer,
The resulting copolymer can be modified as appropriate, such as by crosslinking.

In the present invention, the content of a fluorovinyl compound (W) having a specific carbonic acid type functional group is related to the performance as a polymer membrane, especially the ion exchange capacity described below, and is preferably 0% in the carbonic acid type fluororesin. The content of the fluorovinyl ether compound (or less) may be employed in a range of about .1 to 50 moles, especially about 1 to 40 moles.The content of the fluorovinyl ether compound (or less) is particularly related to mechanical performance such as flexibility as a polymer membrane. Preferably, 1 to 30 mol%, particularly about 2 to 20 mol%, is employed.

Means for carrying out the copolymerization include peroxy compounds, with or without inert organic or aqueous solvents;
Known means such as carrying out the reaction under the action of a polymerization initiation source such as an ab compound, ultraviolet rays, or ionizing radiation can be employed. For example, Japanese Patent Publication No. 48-2223, Japanese Patent Publication No. 48-207
It is carried out by the method described in Japanese Patent Publication No. 88 and Japanese Patent Publication No. 4B-41942. As for the polymerization method, various methods such as bulk polymerization, solution polymerization, suspension polymerization, and precipitation polymerization are employed.

The fluorine-containing copolymer of the present invention may be a graft copolymer or a block copolymer, but it is a polymer in which carbonic acid type functional groups are uniformly dispersed in the copolymer and has a uniform ion exchange capacity. A copolymer obtained by directly copolymerizing each of the above-mentioned monomer compounds is particularly preferred since a membrane can be obtained.

The carboxylic acid type fluororesin of the present invention obtained by
Due to the need for a mechanical strength of 1- on the membrane or as a polymer membrane, the molecular weight is usually about 5.
000 to 300,000, preferably about 10,000 to 100,000.

Further, the means for forming a polymer membrane from the specific calphone tube type fluororesin can be carried out by any known means, such as press molding, roll molding, extrusion molding, solution casting, dispersion molding, or powder molding. h”7-, .

The carbonic acid-type fluororesin of the present invention may be made of olefin polymers such as polyethylene, polypropylene, etc., preferably fluorine-containing fluorine-containing polymers such as polytetrafluoroethylene and copolymers of ethylene and tetrafluoroethylene, if necessary during film formation. Copolymers can be blended and molded, or woven fabrics such as cloths and nets made of these polymers.

The membrane can be reinforced by supporting the copolymer with a support made of nonwoven fabric or porous film. Nao, huh? The weight of the resin forming the blend or support is
It is not included in the ion exchange capacity value below.

The content of carbonic acid type functional groups may vary over a wide range, but in preferred embodiments is selected from a wide range of 0.01 to 5 milliequivalents/gram dry resin in terms of ion exchange capacity as described below. The ion exchange capacity is preferably 0.
．． A level 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 carbonic acid type fluororesin is preferably 50°C or higher, preferably about 70 to 500°C when expressed as the T9 value described below. .

In this specification, the term "tqj" 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 one polymer, is 100 md/sec. In this case, the volume flow rate was determined by using a polymer with a carbonic acid type functional group as a 1'C00CR= group, and applying the polymer to a diameter of 1 m and a length of 2 mm at a constant temperature under a pressure of 50 kg/cd. The melt flows out from the orifice of
It shows the amount of polymer flowing out in units of 1/sec.

[The ion exchange capacity f1 was determined as follows.

That is, a carbonic acid type 7) base resin in which the carbonic acid type functional group is a 1000H group is left in 1N HCI at 60°C for 5 hours to completely convert to the H type and no HCI remains. Wash thoroughly with water.

After that, this H-type resin 0.5f was mixed with 0.1N NaO
In a solution of H25mC and 25ml of water.

It was left standing at room temperature for 2 days. The resin is then taken out, and the amount of NaOH in the solution is determined by back titration with 1N ICI.

The polymer membrane made of carbonic acid type fluororesin used in the present invention is a non-porous σ) uniform membrane I), and its thickness is 1).
~250 microns, preferably about 15 to 180 microns. If the film thickness becomes too thin, the strength and durability of the film will be insufficient. In addition, if the membrane thickness is too thick, the permeation amount of the liquid mixture becomes small and it is not practical.The shape of the polymer membrane is usually used as a Gt flat membrane, but other shapes such as cylindrical or 42 mm It can also be used by increasing the surface area by making it into a shape such as a hollow fiber.Furthermore, it can be used by embedding a reinforcing material such as a cloth inside the membrane, or by laminating the membrane on a porous reinforcing body. Various reinforcing means may be applied.

The method of the present invention uses the above-mentioned carbonic acid type fluororesin membrane, -
It is carried out using a device that is divided into a secondary chamber and a secondary chamber.

- In the next chamber, the organic liquid mixture to be separated or concentrated is placed in liquid form, - The pressure of the crab bill is reduced by an appropriate method, or
or circulating other liquids or gases. 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 is preferably circulated externally or internally, or - agitated by providing a suitable stirring device inside the next chamber. 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 by means of a suitable heating device, such as a heating jacket.

- It is desirable to heat the bottom chamber and the secondary chamber appropriately.

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 reduced. 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 1 normal vacuum to 100 to 9/d, preferably vacuum to about 30 kg/crl; if the pressure is too high, it becomes difficult to maintain the shape of the polymer membrane.

Examples of organic liquid mixtures that can be separated by the method of the present invention include mixtures of various organic substances, such as mixtures of organic substances that cannot be separated by ordinary distillation methods due to the presence of azeotropic points, and mixtures of organic substances whose boiling points are close to each other. This is particularly effective in the case of mixtures of organic substances that are very 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 employed pressure range.

Examples of such organic liquid mixtures include benzene/n-hexane and benzene/n-hexane, which have an azeotropic point.
Mixtures of organic substances such as hexane, methanol/7 setone, benzene/methanol, 7 setone/chloroform; water/isoph c-panol, water/ethanol, water/n
n-purpanol water/allyl alcohol, water/2-methoxyethanol, water/isobutanol, water/n-buta 7
water/2-butanol, water/furfuryl alcohol, water/n-pentanol, water/2-pentanol,
Water/alcohol mixtures such as water/4-methyl-1-butamele; water/tetrahydrofuran, water/dioxane,
Examples include water/organic solvent mixtures such as methyl ethyl ketone.

Also, examples of mixtures whose boiling points are close to each other include ethylbenzene/styrene, p-ri p-ethylbenzene,
p-chlorostyrene, toluene/methylfuclohexane, phtadiene/=/thenes, butadiene/butanes, n
-buteno/'1-butene and the like. Others: water/glycerin, water/g, recalls, water/propylene chlorohydrin, water/propylene dichlorohydrin, water/
Examples include epichlorohydrin, water/hydrazine, and isomer mixtures.

Furthermore, the method of the present invention can be applied to the mixture of stiff straw not only in a one-component system as described above, but also in a multi-component system of three or more components. Of course, the method of the invention may 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 an equal mixture, the more difficult the concentration ratio will be. If the desired purity cannot be obtained by passing through a polymer membrane once (-membrane concentration), the product is passed 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 by such explanations.

Example 1 20.52 CF, = CPO (CF snow), C00CHI, 4.5 in a 200 m1 stainless steel pressure-resistant reaction vessel
9 cr = CFOCsF7 and 18f trick I
:I rottrifluoroethane and 76 μl of azohisisobutylene were charged. After thoroughly degassing with liquid nitrogen,
The reaction vessel was heated to 70°C, and 14°5 kg of tetrafluoroethylene was added.
/crA was charged and the reaction was carried out. After 20 hours, a 9.5F copolymer was obtained. The copolymer was press-molded at 180°C to form a film with a thickness of 100μ, then hydrolyzed in caustic soda, treated with pure water at 90°C for 16 hours, and then dried at 70°C for 24 hours to form an ionized film. Exchange capacity 1
．． A film of 2 n+@q/f was obtained.

Using the pancreas, a mixture of water and isopropanol (isopropano-IL/water-82/1) was prepared by pervaporation.
8, weight ratio) were separated. Temperature 40℃, permeation side pressure 10
Isopropano-/ of water obtained at -'i+mHg
The separation coefficient for l· is 25.2, and the permeation amount is 31
C1/fi”・hr.

Example 2 18.82 of trichlorotrifluoroethane, 80 of 7zobisisobutyronitrile and 285F of CF were placed in a 200 me stainless steel pressure reactor.
CFOCF, CF2C00CR, and 5. Of's CF
i = CFoci FuCF1 was charged. After degassing with liquid nitrogen.

Raise the temperature to 70℃. Then, add tetrafluoroethylene to 14.0
Start the Preparation 1 reaction until it reaches kg/cm 7, :, 2
After 4 hours, a white coelectric material of 5.9 f was obtained with a thickness of 100 mm.
〃 film. After hydrolyzing the film in caustic soda, the functional group was changed to -COOH type in hydrochloric acid, treated with pure water at 90°C for 16 hours, and dried at 70°C for 24 hours to give an ion exchange capacity of 1.18. A film of m@q:/f was obtained.

A mixed solution of water and ethanol (ethanol/water = 9476, weight ratio) was separated by pervaporation using a loading/unloading device. The separation coefficient of the tl water obtained at 40° C. and 10 −1 to Hg was 5.68 with respect to ethanol, and the permeation amount was 72 atim·hr.

Procedural amendment (letter) April 2, 1980 Haruki Shimada, Commissioner of the Japan Patent Office1, Indication of the case, Patent Application No. 188389 filed in 19882, 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 M

Claims (1)

[Scope of Claims] A liquid mixture having at least an organic liquid as one of its constituents is treated with a ``refine compound'' of the general formula CF22cx-(ocr,cry), -(0)IIl-
(CFY') -A (where, X is an atom atom or -CF
, where Y and Y' are fluorine atoms or carbon atoms 1 to 10
is a perfluoroalkyl group, l is 0 to 5, m is 0
~1, n is 1 to 12, A is -COOH, = -CO
F. -CN, -COOR', -Coo・÷M or -C
is one of ONR snow R3, Hli is an alkyl group having 1 to 20 carbon atoms, M is a metal atom or -NR'R''HIR7,
X is the valence number of M, )(*, Hl, R4, R',
R6 and Rf are hydrogen atoms or one of R1) is a fluorovinyl compound Ql) having a first carbonic acid type functional group, and the general formula % is as described above. A polymer consisting of a ternary copolymer with a fluorovinyl ether compound 4 (perfluorofurkyl group having numbers 1 to 12) and whose ion exchange capacity is 0.01 to 5j IJ equivalent/g dry resin. A method for separating a liquid mixture, the method comprising separating a liquid mixture by pervaporation using a membrane.