JPS5892407A - Separation of liquid mixture - Google Patents

Abstract

PURPOSE:To carry out efficient operation in separating or concentrating an org. liquid mixture by pervaporization, by using a fluorinated olefinic terpolymer membrane. CONSTITUTION:In separating or concentrating a mixture of org. liquids or a mixture of in org. liquid and water by pervaporization, a high molecular membrane comprising a terpolymer of fluorovinyl, fluorinated olefin and olefin is used to carry out separating or concentrating operation excellent in efficiency and a speed. An operation temp. is pref. 0-200 deg.C and operation pressure is pref. 0-100kg/cm<2>. The thickness of the high molecular membrane is 1-250mu and said membrane may be laminated on a porous support. As the mixture to be treated, benzene/cyclohexane, methanol/acetone, water/isopropanol or water/ ethanol are designated.

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.
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 permeable substances are 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 low relative volatility with close boiling waste, and mixtures containing substances that polymerize or modify when heated. has been done.

Conventionally, membranes made of polyethylene, polypropylene, cellulose-based polymers, polyacrylonitrile, polyamide, polyester, polystyrene, polytetrafluoroethylene, or copolymers thereof have been known as polymer membranes used in such separation methods. It is being However, when such a membrane is used to separate an organic liquid mixture by pervaporation, the following practical difficulties are observed. That is, (1) Since the concentration ratio (separation coefficient αAB) of an organic liquid mixture passing through a polymer membrane once is small, it is necessary to use a very large number of membranes in order to concentrate or separate the organic liquid mixture to the desired concentration. must be passed. Generally, the separation coefficient αAB is of the order of magnitude.

0-1171L ABA+/B+ (2) Since the amount of permeation of an organic liquid mixture through a polymer membrane (generally expressed as the amount of permeation per unit membrane surface area, unit membrane thickness, and unit time) is small, the membrane surface area must be made extremely large or the thickness of the polymer membrane must be made extremely thin. Therefore, in the former case, the equipment cost becomes excessive, and in the latter case, problems arise in the strength and durability of the membrane.

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

The present inventor has conducted various studies on means for separating and concentrating various organic liquid mixtures by pervaporation.
As a result of repeated studies, a polymer film made of a copolymer of a fluorinated olefin compound such as tetrafluoroethylene, a fluorovinyl compound having a carboxylic acid type functional group, and an olefin compound such as ethylene has been found to smoothly and advantageously overcome the above-mentioned difficulties. I found a solution. .

That is, the present invention provides a liquid mixture having at least an organic liquid as one of its components, which has the general formula 0%) to 12, X is a fluorine atom or -CF3, and Y
and Y' is a fluorine atom or a perfluoroalkyl group having 1 to 10 carbon atoms, AB -CN, -COF.

-COOH, -coon7, -coo --M or -〇〇NR2R3, R1 is an alkyl group having 1 to 20 carbon atoms, M is a metal atom -NR'R5R' R7, X is the valence number of M and R1, R3, R4, R11, R6
and R7 is a hydrogen atom or one of R1) (11 and the general formula CF2=CZ
Z' (here, Z and Z' are -H, -cl, -F or -
CF3) is a fluorinated olefin compound (Ill) and the general formula CH2=CR'R' (here,
R8 and R9 are a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or an aromatic nucleus)
The present invention provides a novel method for separating liquid mixtures, which is characterized by separation by pervaporation using a polymer membrane made of a terpolymer of

In the present invention, when obtaining a copolymer that forms a specific polymer membrane, the above fluorovinyl compound (1
The composition ratio of 1, the fluorinated olefin compound, and the olefin compound is important because it is related to all olfactory performance. First, the amount of fluorovinyl compound (11) is directly related to the ion exchange capacity of the membrane, but it is preferably 0.1 to 50 mol in the copolymer, particularly 1 to 40 mol.
Molarity is preferred. When the amount of the compound (11) is large, a membrane with high ion exchange capacity can be obtained. , (ff
The abundance of J+ olefinic compounds is related to the mechanical properties of the membrane. In the present invention, olefin compound container)/
The molar ratio of the fluorinated olefin compound rn) is preferably from 5/95 to 70/30°, especially from 111/9n to <SO
/40 is preferable.

The copolymer constituting the polymer membrane of the present invention is (11(IT
) and @) consisting of a terpolymer of specific monomer compounds. Here, the fluorovinyl compound (■) is represented by the general formula (%) as described above. In the formula, X, Y, Y', 1, m, and A are the same as above, but from the standpoint of performance and availability, X is a fluorine atom, Y is a fluorine atom, and Y is -Fll is 0 to 1, m is D to 1, n is 0 to 8, and A
100F, -C'OO due to ease of copolymerization reaction etc.
R' is particularly preferred. Preferred representative examples of such fluorovinyl compounds include CF2==CFO(CF2)+ ~B COOCH
3, CF2: CFO(CF2)+, s' COF
, CF2 "CF2CF2 CF (CF3)o
CF2 CF2 COOCH3, CF22CFOCF2
CF2 (CFs) COF20F2 COF.

Examples include CF2=CF-(CF2)o ~5cOOcHs.

In addition, the second monomer compound in the present invention (
The old fluorinated olefin compound is represented by the following general formula as described above.

CF22czz' Here, 2 and Z' are -Fl-cl, -H or -CF
3, and its preferred representative examples are tetrasulfonated ethylene,
Examples thereof include ethylene chloride trifluoride, propylene hexafluoride, ethylene trifluoride, vinylidene fluoride, and vinyl fluoride. Among these, perfluoro compounds are preferred, and ethylene tetrafluoride is particularly preferred.

Furthermore, the third monomer compound in the present invention, O
The olefin compound of I[l is represented by the following general formula as described above.

Here, R8 and R9 represent -H, an alkyl group having 1 to 8 carbon atoms, or an aromatic nucleus. Preferred representative examples include ethylene, propylene, butene-1, isobutylene, styrene, α-methylstyrene, pentene-1, hexene-1,
1, heptene-1,3-methyl-butene-1,4-methylpentene-1, among others, production-
Ethylene, propylene, and inobutylene are particularly preferred in terms of F and the performance of the resulting membrane.

In addition, A in the specific polymer membrane of the present invention is selected as described above from the viewpoint of copolymerization reactivity, etc., and may also be selected as appropriate depending on the organic liquid mixture to be pervaporated. obtain.

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'Fl'R'.

In producing the above copolymer, the resulting copolymer can be modified by using one or more of the above compounds and also copolymerizing other monomers. For example, CF2=CFORf (Rf is carbon number 1 to 1
By using a perfluoroalkyl group (0 perfluoroalkyl group),
Further flexibility can be imparted to the resulting membrane, or CF2=
CF-CF2CF2, CF2=CF-0(CF2)! ,
By using a divinyl monomer such as 5-OC'F=CF2 in combination, the resulting copolymer can be crosslinked. Furthermore, one or more types of other functional monomers having a sulfonic acid type functional group can also be used in combination.

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 azo compound, ultraviolet rays, or ionizing radiation can be employed. For example, Japanese Patent Publication No. 4R-2223, Japanese Patent Publication No. 48-2 [1
It can be carried out by the method described in Japanese Patent Publication No. 788 and Japanese Patent Publication No. 48-41942. As for the polymerization method, various methods such as bulk polymerization, solution polymerization, suspension polymerization, and precipitation polymerization can be adopted.

The fluorine-containing copolymer of the present invention may be a graft copolymer or a block copolymer, but the carboxylic acid type functional group is uniformly dispersed in the copolymer, and the polymer film has a uniform ion exchange capacity. A copolymer obtained by directly copolymerizing each of the above-mentioned monomer compounds is particularly preferred in that it provides the following.

In the present invention, means for forming a polymer membrane from a fluorine-containing copolymer having a specific carboxylic acid type functional group (hereinafter abbreviated as carboxylic acid type fluororesin) as described above may be any known means, For example, press molding, roll molding, extrusion molding, solution casting, dispersion molding, powder molding, etc. are used.

In the present invention, the content of the carboxylic acid type functional group of the carboxylic acid type fluororesin can be adopted over a wide range, but J
In a preferred embodiment, the ion exchange capacity described below is 0.01.
Selected from a wide range of ~3 mm/t/g dry resin. The ion exchange capacity is preferably 0.1 to 2.
An IJ equivalent of about 7/g dry resin is adopted.

Further, from the viewpoint of mechanical strength as a polymer membrane, the molecular weight of the carboxylic acid type fluororesin is preferably 50° C. or more, preferably about 70 to 30,000 when expressed by the TQO value described below.

In this specification, the term "TQ" is defined as follows. That is, the temperature at which the volume flow rate is 100 mtx3/sec, which is related to the molecular weight of the polymer, is defined as Tq. In this case, the volumetric flow rate is determined by using a polymer in which the carboxylic acid type functional group is -C○OCH3 group, and applying the polymer under a pressure of 30 kg/d, at a constant temperature, with a diameter of 1 mm and a length of 2 liters. There is a graph C that shows the amount of polymer melted and flowed out from an orifice in units of 3/sec.

In addition, "ion exchange capacity" was determined as follows. That is, a carboxylic acid type fluororesin with a carboxylic acid type functional group of 1000H group was left in 1N HCl at 60°C for 0.5 hours to completely convert it to the H type, and to prevent Hcl from remaining. Wash thoroughly with water.

Then, 0.5 g of this H-type resin was mixed with 0.1N NaO
It was left standing at room temperature for 2 days in a solution prepared by adding 25 liters of H25m/K water. The resin is then taken out and the amount of Na OHO in the solution is determined by back titration with 0.1N HCl.

The carboxylic acid type fluororesin of the present invention may be made of an olefin polymer such as polyethylene or polypropylene, preferably a fluorine-containing polymer such as a polyfluoroethylene or a copolymer of ethylene and tetrafluoroethylene, if necessary during film formation. The copolymer can be blended and molded, or the membrane can be reinforced by supporting the copolymer with a support made of cloth, net, or other fabric, nonwoven fabric, or porous film made of these polymers. can. Nao, ka\
The weight of the resin forming the blend or support is not included in the above ion exchange capacity values.

The polymer film made of carboxylic acid type fluororesin used in the present invention is a non-porous uniform film, and the film thickness is 1 to 25 mm.
0 micron, preferably about 5 to 18 microns.If the film thickness is too thin, the film will lack strength or durability.Also, if the film thickness is too thick, , the amount of permeation of the liquid mixture becomes small, making it impractical.The shape of the polymer membrane is usually used as a flat membrane, but
Other shapes such as a cylindrical shape or a hollow fiber shape can also be used 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 uses the above-mentioned carboxylic acid type fluororesin membrane, -
It is carried out using a device that is divided into a secondary chamber and a secondary chamber.

- The next chamber contains the organic liquid mixture to be separated or concentrated in liquid form, - The pressure in the crab firebox 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. It is usually desirable to appropriately heat the secondary chamber and/or the secondary chamber using a suitable heating device, such as a heating jacket.

The separation method of the present invention is carried out over a wide range of temperatures, typically from 0 to 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. Further, the usable pressure range is usually vacuum to 100 kg/cri', preferably vacuum to 3 n kg/cm2 or about 1 degree; if the pressure is too high, it becomes difficult to maintain the shape of the polymer membrane.

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

However, the organic liquid mixture needs to be in a liquid state in its mixed state within the above-mentioned implementation temperature range and at normal pressure or within the 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 such as hexane, methanol/acetone, benzene/methanol, acetone/chloroform; water/isopropanol, water/ethanol, water/n
-Glopanol, water/allyl alcohol, water/2-methoxyethanol, water/isobutanol, water/n-butanol, water/2-butanol, water/furfuryl alcohol, water/n = pentanol, water/2-pen Examples include water/alcohol mixtures such as tanol and water/4-mef-1-butanol; water/organic solvent mixtures such as water/tetrahydrofuran, water/dioxane, and water/methyl ethyl ketone.゛Also, as mixtures whose boiling points are close to each other, ethylpene, yne/styrene, P-chloroethylbenzene/P-chlorostyrene, toluene/methylcyclohexane, butadiene/butenes, butadiene/butanes, n
-butene/coptene, etc. Others, water/
Examples include glycerin, water/glycols, water/propylene chlorohydrin, water/propylene dichlorohydrin, water/epichlorohydrin, water/hydrazine, and isomer mixtures.

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

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

Example 1 32.5f CF22CFOCF2 C'l'i'' (C
'Fs)O(CF2).

C○○CH3, 18f/ trichlorotrifluoroethane, and 80m9 azobisisobutyronitrile to 2
The mixture was placed in a stainless steel pressure-resistant reaction vessel of 00 m/cm. After sufficiently degassing with liquid nitrogen, the reaction vessel was heated to 700C, and a mixed gas of tetrafluoroethylene and ethylene (molar ratio of tetrafluoroethylene and ethylene: 92/8') was added at 12.5 kg/cIn.
2 was prepared and the reaction was carried out.

During the reaction, a mixed gas of tetrafluoroethylene and ethylene with a molar ratio of 60/4n was introduced into the system, and the polymerization pressure was increased to 12.5 kg/
cm'' K was maintained. After 2 hours, a white copolymer of 7.29 was obtained. The TQ of this copolymer was 240°G, and in the polymer (r) CF2==cF'ocF'2CF(CF
3) The molar ratio of 0 (CF2)3 COOCH3, tetrafluoroethylene, and ethylene is 26.5:44.0:
It was 29.5. The copolymer was press-molded at 260'C to form a film with a thickness of 100μ.

After hydrolyzing the film in caustic soda,
The membrane was treated at 0°C for 16 hours and then dried at 70°C for 24 hours to obtain a membrane with an ion exchange capacity of 1.49 meq/g. A mixture of water and Impropatool (Isopropatool/Water = 82/18,
weight ratio) was separated. Temperature 406C1 Permeate side pressure 10-
The separation coefficient of water for menproper tool obtained at 1 Hg is 17.5, and the permeation amount is 5209
/ m2・hr.

Example 2 20.5 g of CF in a 2 nnml stainless steel reaction vessel
2: Charge CFO(CF2)3COOCH3, 18g of trichlorotrifluoroethane, and 80rn9 of azobisisobutyronitrile. After degassing, the reaction vessel was heated to 70°C and a mixed gas of tetrafluoroethylene and ethylene (
C2F4/C2H4 nomolar ratio 8n/20) & 15.5 +91/crn2! The reaction was carried out using the following method.

A mixed gas of tetrafluoroethylene and ethylene with a molar ratio of 53/47 was introduced into the reaction system, and the polymerization pressure was increased to 15.5 kl.
? /ryn2. As a result, a terpolymer with an ion exchange capacity of 1.78 meq was obtained. The copolymer was press-molded into a film with a thickness of 100 μm. After hydrolyzing the film thus obtained in caustic soda,
The functional group was changed to -COOH type in hydrochloric acid, and the mixture was heated at 90°C in pure water for 1
It was treated for 6 hours and 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. The separation coefficient of the obtained water with respect to ethanol at 40°C and 10-lmmHg was 4.47, and the permeation amount was 1030 g/m2·br.

Example 3 CF,, =CF○(CF2)3COOCH3:tetrafluoroethylene:ethylene molar ratio is 18.1/57.3
/24.6, and the ion exchange capacity is 1.52 meq
/g of the copolymer was prepared in the same manner as in Example 1. The copolymer was press-molded into a 100μ thick film.

The film was hydrolyzed in lithium hydroxide and diluted with pure water at 9%
After processing at n°C for 16 hours, it was dried at 70°C for 24 hours to obtain a film with -COOLi type functional groups. A separation experiment similar to that in Example 2 was conducted using this membrane, and as a result, the separation coefficient and permeation amount were each 4.96.5849/m2·hr.

April 1980, Commissioner of the Patent Office Haruki Shimada1, Indication of the case Patent Application No. 189257 of 19892, Name of the invention Method for separating liquid mixtures3, Person making the amendment Case and Relationship Patent applicant address 2-1-2 Marunouchi, Chiyoda-ku, Tokyo Name (
004) Asahi Glass Co., Ltd. 4, Agent No. 2 Okada Building 6, Number of inventions increased by amendment None 7, Subject of amendment Specification

Claims (1)

[Claims] A liquid mixture having at least an organic liquid as one of its constituents is defined by the general formula CF2-=CX-(OC'l'i'2
CFY), -(o)m-(CFY')ゎ-A (where 1 digit is 0-6, m is O-1, n is 1-12,
X is a fluorine atom or -0F3, Y and Y' are a fluorine atom or a perfluoroalkyl group having 1 to 10 carbon atoms, and humans are -CN, -COF, -COOH, -C0
0R', -Coo --M or -CoNR2R3, R1Id is an alkyl group having 1 to 20 carbon atoms, M is a metal atom, or -NR'R5R'R', X is the valence number of M, R2R3, R4 , R5, R6 and R7 are one of hydrogen atoms or R1), and the general formula CF2=CZZ' (where Z
and Z' is -H1-cl, -F or -〇F3), and a fluorinated olefin compound represented by the general formula CH2CF18R9 (wherein R8 and R9 are hydrogen atoms or carbon atoms 1 to 8 (alkyl group or aromatic nucleus)
1. A method for separating a liquid mixture, which comprises separating a liquid mixture by nitrogenation using a polymer membrane made of a terpolymer with an olefin compound (III) represented by: