GB1604102A - Laminar structures of fluorinated ion exchange polymers - Google Patents
Laminar structures of fluorinated ion exchange polymers Download PDFInfo
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- GB1604102A GB1604102A GB15537/78A GB1553778A GB1604102A GB 1604102 A GB1604102 A GB 1604102A GB 15537/78 A GB15537/78 A GB 15537/78A GB 1553778 A GB1553778 A GB 1553778A GB 1604102 A GB1604102 A GB 1604102A
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- tetrafluoroethylene
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B27/00—Layered products comprising a layer of synthetic resin
- B32B27/32—Layered products comprising a layer of synthetic resin comprising polyolefins
- B32B27/322—Layered products comprising a layer of synthetic resin comprising polyolefins comprising halogenated polyolefins, e.g. PTFE
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B27/00—Layered products comprising a layer of synthetic resin
- B32B27/30—Layered products comprising a layer of synthetic resin comprising vinyl (co)polymers; comprising acrylic (co)polymers
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F16/00—Homopolymers and copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an alcohol, ether, aldehydo, ketonic, acetal or ketal radical
- C08F16/12—Homopolymers and copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an alcohol, ether, aldehydo, ketonic, acetal or ketal radical by an ether radical
- C08F16/14—Monomers containing only one unsaturated aliphatic radical
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
- C08J5/20—Manufacture of shaped structures of ion-exchange resins
- C08J5/22—Films, membranes or diaphragms
- C08J5/2206—Films, membranes or diaphragms based on organic and/or inorganic macromolecular compounds
- C08J5/2218—Synthetic macromolecular compounds
- C08J5/2231—Synthetic macromolecular compounds based on macromolecular compounds obtained by reactions involving unsaturated carbon-to-carbon bonds
- C08J5/2237—Synthetic macromolecular compounds based on macromolecular compounds obtained by reactions involving unsaturated carbon-to-carbon bonds containing fluorine
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2457/00—Electrical equipment
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J2327/00—Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Derivatives of such polymers
- C08J2327/02—Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Derivatives of such polymers not modified by chemical after-treatment
- C08J2327/12—Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Derivatives of such polymers not modified by chemical after-treatment containing fluorine atoms
- C08J2327/18—Homopolymers or copolymers of tetrafluoroethylene
Abstract
Fluorinated ion exchange polymers which have pendant side chains which contain groups wherein W is F or CF3, and R is an inonizable group, or which have such pendant side chains and also pendant side chains which contain sulfonyl groups, when used in the form of membranes to separate the anode and cathode compartments of an electrolysis cell, permit operation at high current efficiency. They can be made by copolymerization of a mixture of monomers, one of which is a vinyl monomer which contains the indicated carboxylic funtional group.
Description
(54) LAMINAR STRUCTURES OF FLUORINATED
ION EXCHANGE POLYMERS
(71) We, E. I. DU PONT DE NEMOURS AND COMPANY, a
Corporation organised and existing under the laws of the State of Delaware, United
States of America, located at Wilmington, State of Delaware, United States of
America, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention concerns a laminar structure of fluorinated ion exchange polymers suitable for use in chloralkali electrolysis cells.
Fluorinated ion exchange membranes are known in the art. The fluorinated ion exchange polymer in such membranes can be derived from a fluorinated precursor polymer which contains pendant side chains in sulfonyl fluoride form.
The sulfonyl fluoride functional groups have been converted to ionic form in various ways, for example, to sulfonate salts by hydrolysis with an alkaline material, to the sulfonic acid by acidification of the salts, and to the sulfonamide by treatment with ammonia. Examples of such teachings in the art can be found in
U.S. 3,282,875, U.S. 3,784,399, and U.S. 3,849,243.
Although such polymers and membranes have many desirable properties which make them attractive for use in the harsh chemical environment of a chloralkali cell, such as good long-term chemical stability, their current efficiencies are not as high as is desired, especially when the caustic is produced at high concentration. As transport of hydroxyl ion in a chloralkali cell frpm the catholyte through the membrane to the anolyte increases, current efficiency drops. Larger amounts of oxygen impurity in the chlorine are thereby produced, and there is a greater buildup of chlorate and hypochlorite contaminants in the brine, which contaminants must be removed and discarded to maintain acceptable cell operation. Current efficiencies of at least 90 / are highly desirable.
Accordingly, there is a need for membranes which will permit cell operation at high current efficiencies, and especially for those which will permit operation at high efficiencies over long periods of time.
It has now been found that laminar structures of fluorinated ion exchange polymers which contain pendant side chains in ionic carboxylic form and optionally also in ionic sulfonyl form have high current efficiencies.
More specifically, according to the present invention, there is provided a laminar structure having a base layer of a fluorinated ion exchange polymer, and having on at least one surface thereof a layer of a polymer having the repeating units:
whereinnis 1 or2,pis 1 to 10, q is 3 to 15,ris0to lOsisO, 1, 2 or 3, the X's taken together are four fluorines or three fluorines and one chlorine, W is F or CF3, Y is F or CF3, Z is F or CF3, R' is H, lower alkyl or
R2 is F, Cl or OR3, R3 is H or
M#1# t M#1# t M is alkali metal, alkaline earth metal, ammonium or quaternary ammonium, and t is the valence of M, the polymer of each layer having an equivalent weight no greater than 2000.
Preferred laminar structures are those wherein the layer of polymer on the base layer contains a polymer
(a) wherein R1 is H or
R2 is OR3, and R3 is H or
M#1# t M#1# t and/or either
(b) wherein r is O, W is F, the X's taken together are four fluorines, n is 1 to Y is CF3; or
(c) wherein r is at least 1, W is F, R' is H or
M#1# t Y is CF3, and Z is CF3.
Preferably the base layer is a fluorinated ion exchange polymer which has pendant side chains which contains {)CF2CF2SO2R2 groups wherein R2 is F, Cl or OR3; R3 is H or
M#1# t M is alkali metal, alkaline earth metal, ammonium; or quaternary ammonium and t is the valence of M.
The laminar structures fabricated of copolymers which contain ionizable carboxylic, or both ionizable carboxylic and su fonyl groups, as active ion exchange sites are highly desirable in comparison with prior art ion exchange membranes for several distinct reasons. Most importantly, outstanding efficiencies in a chlor-alkali cell have been obtained with laminar structurs thereof in comparison with similar structures whch contain only sulfonic acid ion exchange groups obtained by hydrolysis of pendant sulfonyl groups. This improvement is considered to be of predominant importance in commercial applicability in reducing the cost of producing a unit of chlorine and caustic. Illustratively, in a chlor-alkali plant producing, for example, 1000 tons per day of chlorine, the direct savings in electrical power for only 1% increase in efficiency are very significant.
The polymers used in the laminar structures of the present invention are characterized by their outstanding stability toward caustic. It has been found, for example, that the polymers are significantly more stable toward caustic than similar polymers wherein the carboxylic groups are in pendant side chains of the polymer which terminate as -OCF3COOR groups.
A need has developed in the chlor-alkali industry for improved ion exchange materials which can be used to replace existing cell compartment separators which have been used for decades without substantial improvement in design.
For use in the environment of a chlor-alkali cell, the membrane must be fabricated from a material which is capable of withstanding exposure to a hostile environment, such as chlorine and solutions which are highly alkaline. Generally, hydrocarbon ion exchange membranes are totally unsatisfactory for this kind of use because such membranes cannot withstand this environment.
For commercial use in the chlor-alkali industry, a film must go beyond the ability to be operable for prolonged time periods in the production of chlorine and caustic. A most important criterion is the current efficiency for conversion of brine in the electrolytic cell to the desired products. Improvements in current efficiency can translate into pronounced savings in the cost of production of each unit of chlorine and caustic. Additionally, from a commerical standpoint the cost of production of each unit of products will be determinative of the commercial suitability of an ion exchange membrane.
The ion exchange polymers used in the laminar structures of the present invention possess pendant side chains which contain carboxylic, or both carboxylic and sulfonyl groups, attached to carbon atoms having at least one fluorine atom connected thereto, as set forth above.
The ion exchange polymers which possess pendant side chains which contain carboxylic, or both carboxylic and sulfonyl groups, possess general utility as ion exchange resions. When used in a laminar structure to separate the anode and cathode compartments of an electrolysis cell, such as a chloroalkali cell, the polymer should have a total ion exchange capacity of 0.5 to 1.6 meq/g (milliequivalents/gram), preferably from 0.8 to 1.3 meq/g. Below an ion exchange capcity of 0.5 meq/g, the electrical resistivity becomes too high, and above 1.6 meq/g the mechanical properties are poor because of excessive swelling of the polymer. The values of p, q and r in the above formulas of the copolymer should be adjusted or chosen such that the polymer has an equivalent weight no greater than about 2000, preferably no greater than about 1500, for use as an ion exchange barrier in an electrolytic cell. The equivalent weight above which the resistance of a laminar structure becomes too high for practical use in an electrolytic cell varies somewhat with the thickness of the laminar structure. For thinner laminar structures, equivalent weights up to about 2000 can be tolerated. For most purposes, however, and for laminar structures having a thickness of ordinary membranes, a value no greater than about 1500 is preferred.
The polymers can be made by copolymerizing a mixture of the appropriate monomers. The carboxylic-containing monomer is one or more compounds from first group represented by the formula
wherein
R' is H, lower alkyl or
M(tl) M is alkali metal, alkaline earth metal, ammonium or quaternary ammonium, t is the valence of M,
W is F or CF3,
Y is F or CF3, and n is 1 or 2.
The most preferred monomers or those wherein R1 is H or lower alkyl, generally C, to C5, because of ease in polymerization and conversion to ionic form. Those monomers wherein n is 1 are also preferred because their preparation and isolation in good yield is more easily accomplished than when n is 2.
Preparation of those monomers wherein R1 is lower alkyl is described in
Application No. 15526/78 (Specification No. 1593222).
The compounds
whose preparation is described therein, and the corresponding free carboxylic acids are especially useful monomers.
The carboxylic-containing monomer of the first group is copolymerized with chlorotrifluoroethylene or tetrafluoroethylene or mixtures thereof.
Optionally, there may be included along with the monomers from the first and second groups, one or more monomers from a third group, which is the sulfonylcontaining monomers of the formula
wherein s and Z are as hereinbefore defined and A is F or Cl, preferably F.
Illustrative of such sulfonyl fluoride containing comonomers are
CF2=CFOCF2CF2SO2F,
The most preferred sulfonyl fluoride containing comonomer is perfluoro(3,6 dioxa - 4 - methyl - 7 - octenesulfonyl fluoride),
The sulfonyl-containing monomers are disclosed in such references as U.S.P.
3,282,875, U.S.P. 3,041,317, U.S.P. 3,718,627 and U.S.P. 3,560,568.
The copolymers can be prepared by general polymerization techniques developed for homo- and copolymerizations of fluorinated ethylenes, particularly those employed for tetrafluoroethylene which are described in the literature.
Nonaqueous techniques for preparing the copolymers include that of U.S.P.
3,041,317, that is, by the polymerization of a mixture of the desired component monomers in the presence of a free radical initiator, preferably a perfluorocarbon peroxide or azo compound, at a temperature in the range W200 C and at pressures in the range 1--200, or more atmospheres. The nonaqueous polymerization may, if desired, be carried out in the presence of a fluorinated solvent. Suitable fluorinated solvents are inert, liquid, perfluorinated hydrocarbons, such as p erfluoromethyl cyclohexan e, perfluorodimethylcyclobutane, perfluorooctane, perfluorobenzene and the like, and inert, liquid chlorofluorocarbons such as 1,1,2 - trichloro - 1,2,2 trifluoroethane, and the like.
Aqueous techniques for preparing the copolymers include contacting the monomers with an aqueous medium containing a free-radical initiator to obtain a slurry of polymer particles in non-water-wet or granular form, as disclosed in U.S.
Patent 2,393,967, or contacting the monomers with an aqueous medium containing both a free-radical initiator and a telogenically inactive dispersing agent, to obtain an aqueous colloidal dispersion of polymer particles, and coagulating the dispersion, as disclosed, for example, in U.S.P. 2,559,752 and U.S.P. 2,593,583.
The layer of polymer on the base layer can, for example, be 0.05 to 0.5 mm (0.002 to .02 inch) thick. Excessive thicknesses will aid in obtaining higher strength, but with the resulting deficiency of increased electrical resistance.
The laminar structures can have as one layer a support, such as a fabric, imbedded therein.
It is possible according to the present invention for the polymer in the layer on the base layer to have pendant side chains which are essentially wholly (i.e., 90 /O or more) or wholly (i.e., 99% to 100%) in the carboxylic form or which are in carboxylic and sulfonyl form, for example 10 to 90% of each. Control in this respect is exercised in the choice of the mixture of monomers used in the polymerization.
When a precursor polymer contains sulfonyl halide (-SO3A) groups, it can be treated with water, caustic, or other reagents such as ammonia or an amine to convert the sulfonyl halide groups to sulfonic acid groups or metal, ammonium or quaternary ammonium salts thereof.
So that the laminar structure will have as low an electrical resistivity as possible, it is desirable that essentially all of the carboxylic and sulfonyl groups in the polymer of the layer on the base layer be in the form of active cation exchange groups, i.e. carboxylic and optionally sulfonyl groups of a type which will ionize or form metal salts. In this respect, it is highly undesirable for a film or membrane to be used for ion exchange purposes in an electrolytic cell to have a neutral layer, or that a film or membrane to be used in a chloroalkali cell have either a neutral layer or an anion exchange layer. The laminar structures of the present invention do not have neutral or anion exchange layers. In this context, fiber or fabric reinforcing is not considered as a neutral layer, inasmuch as such reinforcing has openings, i.e., its effective area is not coextensive with the area of the laminar structure. In the case of laminar structures to be used as separators in a chloroalkali cell, polymers which contain 40 100% pendant side chains containing carboxylic groups and 0 60% pendant side chains containing sulfonyl groups provide excellent current efficiency. Those polymers wherein 100% of the functional groups are carboxylic groups, i.e., where r is zero in the structural formula, provide the highest current efficiency.
An equally important criterion in a chloroalkali cell, however, is the amount of power required for each unit of chlorine and caustic. It is considered that the polymers of the type disclosed herein permit a proper combination of operating conditions to realize an excellent and unexpected reduction in power. Since the power requirement (which may be expressed in watt-hours) is a function of both cell voltage and current efficiency, low cell voltages are desirable and necessary.
However, a polymer without a high current efficiency cannot operate effectively from a commercial standpoint even with extremely low cell voltages. Additionally, a polymer with an inherent high current efficiency allows a proper combination of parameters as in fabrication into the laminar structure and/or operation of the electrolytic cell to release the potential theoretical reduction in power. Illustratively, the polymer can be fabricated at a lower equivalent weight which may result in some loss of current efficiency which is more than compensated by a reduction in voltage. Polymers which have 5095% pendant side chains containing carboxylic groups and 5-50% pendant side chains containing sulfonyl groups have low power consumption.
The fluorinated ion exchange polymer of the base layer can have pendant side chains wholly in sulfonyl form, wholly in carboxylic form, or in both carboxylic and sulfonyl form.
When only the layer of polymer on the base layer contains carboxylic groups, the thickness of the carboxylic layer will normally be from 0.01% to 80% of the total thickness. When both layers contain carboxyl groups, the thickness of each layer will be less than half the thickness of the structure, and will normally be from 0.01 to 40% of the thickness. The thickness of a layer which contains carboxylic groups will ordinarily be at least 200 angstroms. The laminar structures can be made by melt-pressing together layers of the desired composition. When only one layer of the structure contains carboxylic groups, that layer can face either the anode or cathode in an electrolysis cell, and in the case of a chloralkali cell it will ordinarily face the cathode.
Under most circumstances, the layered structures will be such that the layer which contains carboxylic groups will be 1/4 to 5 mils thick, the base layer (which will usually contain sulfonyl groups) will be 1 to 15 mils thick, and the total thickness of the structure will be 2 to 20 mils. The indicated thicknesses are effective film thicknesses, i.e. thicknesses which exclude reinforcing fibers and other members which do not contain ion exchange groups.
A specific use for the laminary structures of the present invention is in a chloralkali cell, such as disclosed in German patent application 2,251,660, published April 26, 1973, and Netherlands patent application 72.17598, published
June 29, 1973. In a similar fashion as these teachings, a conventional chloralkali cell is employed with the critical distinction of using the laminar structure to separate the anode and cathode portions of the cell from which chlorine and caustic are respectively produced from brine flowing within the anode portion of the cell.
While the description of said German and Dutch publications is directed to use in a chloralkali cell, it is within the scope of the present disclosure to produce alkali or alkaline earth metal hydroxides and halogen such as chlorine from a solution of the alkali or alkali earth metal salt. While efficiencies in current and power consumption differ, the operating conditions of the cell are similar to those disclosed for sodium chloride.
An outstanding advantage has been found in terms of current efficiency in a chlor-alkali cell with the laminar structures of the present invention.
To further illustrate the present invention, the following examples are provided. Examples 1 to 4 illustrate the preparation of copolymers suitable for use in the layer of polymer on the base layer, while Examples 5 and 6 illustrate the laminar structures of the invention.
Example I
Copolymerization of Tetrafluoroethylene and CF2=CFOCF2CF(CF3)OCF2CF2COOCH3 A 330-ml stainless steel pressure tube was charged with 32.2 g
CF2=CFOCF2CF(CF3)OCF2CF2COOCH3, 20 g tetrafluoroethylene and 15 ml of a solution containing 0.05% perfluoropropionyl peroxide in 1,1,2 - trichloro - 1,2,2 trifluoroethane. After heating for 3 hours at 50 C., the unreacted gases were vented and the liquid and solid product evaporated to dryness. The solid polymeric product was washed thoroughly with aqueous acetone and dried in a vacuum oven to give 3.9 g of white solid. The product was pressed into a clear 54 mil film at 240 C., reacted with a mixture of KOH, dimethyl sulfoxide and water and dried to give a copolymer of tetrafluoroethylene and CF2=CFOCF2CF(CF3)OCF2CF2COO-K+. Infrared spectra showed the presence of appreciable carboxylate salt. Titration indicated the carboxylate content of the final product to be 0.98 meq/g and the equivalent weight to be 1020.
Example 2
Copolymerization of Tetrafluoroethylene and C F2=CFOCF2CF(CF3)OC F2CF2COOCH3 A 330-ml stainless steel pressure tube was charged with 40 g CF2=CFOCF2CF(CF3)OCF2CF2COOCH3, 26 g 1,1,2 - trichloro - 1,2,2 trifluoroethane, 20 g tetrafluoroethylene and 20 ml of a solution containing 0.05 perfluoropropionyl peroxide in 1,1,2 - trichloro - 1,2,2 - trifluoroethane. After heating for 3 hours at 509C., the unreacted gases were vented and the liquid and solid product evaporated to dryness. The solid polymeric product was washed thoroughly with aqueous acetone and dried in a vacuum oven to give 5.5 g of white solid. The product was pressed into a clear 56 mil film at 2400 C., reacted with a mixture of KOH, dimethyl sulfoxide and water, and dried to give a copolymer of tetrafluoroethylene and CF2=CFOCF2CF(C F3)OCF2CF2COO-K+. Infrared spectra showed the presence of appreciable carboxylate salt, while titration indicated the carboxylate content of the product to be 0.838 meq/g, and the equivalent weight to be 1190. The final film had a resistivity of 1.15 ohm-cm2.
Example 3
Copolymerization of Tetrafluoroethylene and CF2=CFO[CF2CF(CF3)O12CF2CF2COOCH3 A 330-ml stainless steel pressure tube was charged with 31.1 g CF2=CFOlCF2CF(CF3)Ol2CF2CF2COOCH3, 20 g tetrafluoroethylene and 15 ml of a solution containing 0.05% perfluoropropionyl peroxide in 1,1,2 - trifhloro 1,2,2 - trifluoroethane. After heating for 3 hours at 500 C., the unreacted gases were vented and the liquid and solid product evaporated to dryness. The solid polymeric product was washed thoroughly with aqueous acetone and dried in a vacuum oven to give 4.3 g of white solid.
Example 4
Copolymerization of Tetrafluoroethylene, CF2=CFOCF2CF(CF3)OCF2CF2SO2F
and C F2=C FOCF2C F(CF3)OC F2CF2COOCH2 A 330-ml stainless steel pressure tube was charged with
25.4 g CF2=CFOCF2CF(CF3)OCF2CF2CF2SO F 8.lug CF2=CFOCF2CF(CF3)OCF2CF2COOCH3, 20 g tetrafluoroethylene and 15 ml of a solution containing 0.05% perfluoropropionyl peroxide in 1,1,2 - trichloro - 1,2,2 - trifluoroethane.
After heating for 3 hours at 50 C., the unreacted gases were vented and the remaining product washed thoroughly with aqueous acetone, filtered and dried in a vacuum oven. The 5.3 g of white solid polymeric product was pressed into a 56 mil film at 2800C. The infrared spectrum of this material showed the presence of appreciable carbomethoxy and sulfonyl fluoride groups having absorptions at 5.6 and 6.8 microns, respectively. After reaction with a mixture of dimethyl sulfoxide, KOH and water, the infrared spectrum showed that all the sulfonyl fluoride and carbomethoxy groups were converted to sulfonate and carboxylate groups, respectively.
Example 5
A piece of 5-mil film of a copolymer of tetrafluoroethylene and perfluoro(3,6 dioxa - 4 - methyl - 7 - octenesulfonyl fluoride) having an equivalent weight of 1100 was placed in a press and one surface covered with 1 g of a powder of a copolymer of tetrafluoroethylene and methyl perfluoro(4,7 - dioxa - 5 - methyl 8 - nonenoate) having an equivalent weight of 980. The material was heated for 4 minutes at 2000C with no pressure and 2 minutes at 2000 under 30,000 psi pressure.
The resulting laminar structure was treated with a mixture of dimethylsulfoxide, water and potassium hydroxide at 900C for 1 hour, and washed and dried to give a clear structure. The infrared spectrum of the resulting 8-8.5 mil thick structure showed very strong carboxylate absorption at 5.95 microns. The structure was placed in a chlor-al ali cell operated at 2.0 asi with the carboxylate side facing the catholyte and aqueous sodium chloride electrolyzed to give 29.537.8% NaOH at current efficiencies of 8591% at a cell voltage of 3.8--4.0 volts.
Example 6
A piece of 7-mil film of a copolymer of tetrafluoroethylene and perfluoro(3,6 dioxa - 4 - methyl - 7 - octenesulfonyl fluoride) having an equivalent weight of 1100, and which had a net of "Teflon" (Registered Trade Mark) T-12 cloth imbedded in it and had one surface layer in which the sulfonyl fluoride groups were converted to the corresponding potassium sulfonate salt to a depth of 0.8 mil, was placed in a press with the sulfonyl fluoride surface up. The upper surface was covered with a powder of a copolymer of tetrafluoroethylene and methyl perfluoro(4,7 - dioxa - 5 - methyl - 8 - nonenoate) having an equivalent weight of 996. The material was heated for 4 minutes at 210"C with no pressure and one minute at 210"C under 30,000 psi pressure. The resulting laminate was treated with a mixture of dimethyl sulfoxide, water and potassium hydroxide at 900C for one hour and washed with water to convert the remaining sulfonyl fluoride groups and ester groups to sulfonate and carboxylate, respectively. The laminate was placed in a chloralkali cell operated at 2.0 asi with the carboxylate side facing the catholyte and aqueous sodium chloride electroylyzed to give 32.338.2% NaOH at current efficiencies of 9096% at a cell voltage of 4.6-4.8 volts.
WHAT WE CLAIM IS:
1. A laminar structure having a base layer of a fluorinated ion exchange polymer, and having on at least one surface thereof, a layer of a polymer having the repeating units:
**WARNING** end of DESC field may overlap start of CLMS **.
Claims (9)
1. A laminar structure having a base layer of a fluorinated ion exchange polymer, and having on at least one surface thereof, a layer of a polymer having the repeating units:
whereinnis 1 or 2,p is 1 to 10, q is 3 to 15,ris0to 10,sis0, 1, 2 or 3, the X's taken together are four fluorines or three fluorines and one chlorine, W is F or CF3, Y is F or CF3, Z is F or CF3, R1 is H, lower alkyl or
R2 is F, Cl or OR3, R3 is H or
tt) Rt) M is alkali metal, alkaline earth metal, ammonium or quaternary ammonium, and t is the valence of M, the polymer of each layer having an equivalent weight no greater than 2000.
2. A laminar structure according to Claim 1, wherein the layer of polymer on the base layer has an equivalent weight no greater than 1500.
3. A laminar structure according to Claim I or 2, wherein R' is H or
R2 is OR3, and R3 is H or
t M#1# t
4. A laminar structure according to any one of Claims 1 to 3 wherein r is 0, W is
F, the X's taken together are four fluorines, n is 1 and Y is CF3.
5. A laminar structure according to any one of Claims I to 3 wherein r is at least 1, W is F, R' is H or
M#1# t Y is CF3, and Z is CF3.
6. A laminar structure according to any one of the preceding claims wherein the base layer is a fluorinated ion exchange polymer which has pendant side chains which contain WCF2CF2SO2R2 groups wherein R2 is F, Cl or OR3; R3 is H or
rt) M is alkali metal, alkaline earth metal, ammonium or quaternary ammonium; and t is the valence of M.
7. A laminar structure according to Claim I substantially as described with reference to Example 5 or 6.
8. An electrolytic cell comprising a housing with separate anode and cathode sections, said cell being separated by a laminar structure as claimed in any one of
Claims 1 to 7.
9. A process for producing halogen and metal hydroxide of an alkali or
alkaline earth metal, or combinations thereof, by electrolysis of a halide of said metal employing separate anode and cathode sections in an electrolytic cell, wherein ions of said metal are passed through a laminar structure as claimed in any one of Claims 1 to 7, the base layer of which laminar structure has sulfonyl groups at least a majority of which are present as ion exchange sites in ionic form, and the surface layer of which faces the cathode section of the cell.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US78972577A | 1977-04-20 | 1977-04-20 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB1604102A true GB1604102A (en) | 1981-12-02 |
Family
ID=25148505
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB15537/78A Expired GB1604102A (en) | 1977-04-20 | 1978-04-19 | Laminar structures of fluorinated ion exchange polymers |
Country Status (15)
| Country | Link |
|---|---|
| JP (2) | JPS53132089A (en) |
| AU (2) | AU525335B2 (en) |
| BE (1) | BE866121A (en) |
| BR (1) | BR7802433A (en) |
| CA (1) | CA1133425A (en) |
| DE (1) | DE2817344A1 (en) |
| FR (1) | FR2388012A1 (en) |
| GB (1) | GB1604102A (en) |
| IL (1) | IL54540A (en) |
| IT (1) | IT1094102B (en) |
| MX (1) | MX151031A (en) |
| NL (1) | NL7804221A (en) |
| NZ (1) | NZ187023A (en) |
| SU (1) | SU1165239A3 (en) |
| ZA (1) | ZA782225B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2233252A (en) * | 1989-05-15 | 1991-01-09 | Pall Corp | Hydrophobic membranes |
Families Citing this family (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4329434A (en) * | 1979-05-31 | 1982-05-11 | Asahi Kasei Kogyo Kabushiki Kaisha | Novel fluorinated cation exchange membrane and process for producing the same |
| DE3050931C2 (en) * | 1979-05-31 | 1994-06-09 | Asahi Chemical Ind | Fluorinated carboxylic acid derivatives and process for their preparation |
| US4329435A (en) | 1979-05-31 | 1982-05-11 | Asahi Kasei Kogyo Kabushiki Kaisha | Novel fluorinated copolymer with tridihydro fluorosulfonyl fluoride pendant groups and preparation thereof |
| DE3036066A1 (en) * | 1980-09-25 | 1982-05-06 | Hoechst Ag, 6000 Frankfurt | Bonding electrode to fluorine contg. copolymer electrolysis membrane - by applying electrode powder to membrane and pressing opt. with heating |
| JPS5792028A (en) * | 1980-11-29 | 1982-06-08 | Asahi Chem Ind Co Ltd | Fluorocarbon cation exchange membrane |
| JPS58189210A (en) * | 1982-04-30 | 1983-11-04 | Daikin Ind Ltd | Production of tetrafluoroethylene/fluorinated alkyl vinyl ether copolymer |
| WO1994003503A2 (en) * | 1992-07-30 | 1994-02-17 | Imperial Chemical Industries Plc | Fluorinated polymers |
| JP2003246906A (en) * | 2002-02-25 | 2003-09-05 | Asahi Kasei Corp | Fluorine-containing copolymer composition |
| US7071271B2 (en) * | 2003-10-30 | 2006-07-04 | 3M Innovative Properties Company | Aqueous emulsion polymerization of functionalized fluoromonomers |
| WO2010066823A1 (en) * | 2008-12-11 | 2010-06-17 | Solvay Solexis S.P.A. | Purification of fluoroionomer compositions |
| JP5799926B2 (en) * | 2012-09-27 | 2015-10-28 | 旭硝子株式会社 | Method for producing fluorine-containing copolymer |
Family Cites Families (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3282875A (en) * | 1964-07-22 | 1966-11-01 | Du Pont | Fluorocarbon vinyl ether polymers |
| FR1527816A (en) * | 1966-02-16 | 1968-06-07 | Du Pont | Perfluorinated alkyl-vinyl ethers bearing substituents, preparation of these ethers by pyrolysis of the corresponding salts, and their use as components of copolymers |
| US3784399A (en) * | 1971-09-08 | 1974-01-08 | Du Pont | Films of fluorinated polymer containing sulfonyl groups with one surface in the sulfonamide or sulfonamide salt form and a process for preparing such |
| US3849243A (en) * | 1971-11-08 | 1974-11-19 | Du Pont | Laminates of support material and fluorinated polymer containing pendant side chains containing sulfonyl groups |
| AU464313B2 (en) * | 1971-12-27 | 1975-08-21 | Hooker Chemicals And Plastics Coup | Electrolysis method and apparatus |
| JPS551351B2 (en) * | 1974-03-07 | 1980-01-12 | ||
| JPS5224176A (en) * | 1975-07-09 | 1977-02-23 | Asahi Chem Ind Co Ltd | Cathion exchange membrane |
| JPS5223192A (en) * | 1975-08-15 | 1977-02-21 | Asahi Glass Co Ltd | Preparation of improved fluoropolymer bearing cation exchange groups |
| GB1518387A (en) * | 1975-08-29 | 1978-07-19 | Asahi Glass Co Ltd | Fluorinated cation exchange membrane and use thereof in electrolysis of an alkali metal halide |
| JPS5228586A (en) * | 1975-08-29 | 1977-03-03 | Asahi Glass Co Ltd | Method for manufacturing an improved fluoropolymer having cation excha nge groups |
| JPS5228587A (en) * | 1975-08-29 | 1977-03-03 | Asahi Glass Co Ltd | Method for manufacturing an improved fluoropolymer having cation excha nge groups |
| JPS52120999A (en) * | 1976-04-05 | 1977-10-11 | Asahi Chem Ind Co Ltd | Electrolysis of alkali metal halides |
-
1978
- 1978-03-15 FR FR7807444A patent/FR2388012A1/en active Pending
- 1978-04-17 AU AU35164/78A patent/AU525335B2/en not_active Ceased
- 1978-04-18 CA CA301,559A patent/CA1133425A/en not_active Expired
- 1978-04-18 JP JP4490778A patent/JPS53132089A/en active Granted
- 1978-04-19 SU SU782605603A patent/SU1165239A3/en active
- 1978-04-19 ZA ZA00782225A patent/ZA782225B/en unknown
- 1978-04-19 BE BE186898A patent/BE866121A/en not_active IP Right Cessation
- 1978-04-19 NZ NZ187023A patent/NZ187023A/en unknown
- 1978-04-19 BR BR787802433A patent/BR7802433A/en unknown
- 1978-04-19 IL IL54540A patent/IL54540A/en unknown
- 1978-04-19 MX MX173172A patent/MX151031A/en unknown
- 1978-04-19 GB GB15537/78A patent/GB1604102A/en not_active Expired
- 1978-04-19 IT IT22494/78A patent/IT1094102B/en active
- 1978-04-20 NL NL7804221A patent/NL7804221A/en not_active Application Discontinuation
- 1978-04-20 DE DE19782817344 patent/DE2817344A1/en active Granted
-
1983
- 1983-11-16 JP JP58214233A patent/JPS59211583A/en active Pending
-
1988
- 1988-03-11 AU AU13048/88A patent/AU1304888A/en not_active Abandoned
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2233252A (en) * | 1989-05-15 | 1991-01-09 | Pall Corp | Hydrophobic membranes |
| GB2233252B (en) * | 1989-05-15 | 1992-11-18 | Pall Corp | Hydrophobic membranes |
Also Published As
| Publication number | Publication date |
|---|---|
| IL54540A0 (en) | 1978-07-31 |
| BR7802433A (en) | 1979-01-16 |
| SU1165239A3 (en) | 1985-06-30 |
| CA1133425A (en) | 1982-10-12 |
| ZA782225B (en) | 1979-04-25 |
| NL7804221A (en) | 1978-10-24 |
| BE866121A (en) | 1978-10-19 |
| MX151031A (en) | 1984-09-12 |
| AU3516478A (en) | 1979-10-25 |
| DE2817344A1 (en) | 1978-10-26 |
| IL54540A (en) | 1981-09-13 |
| AU525335B2 (en) | 1982-11-04 |
| NZ187023A (en) | 1980-11-28 |
| DE2817344C2 (en) | 1990-11-15 |
| FR2388012A1 (en) | 1978-11-17 |
| JPS53132089A (en) | 1978-11-17 |
| JPS59211583A (en) | 1984-11-30 |
| IT7822494A0 (en) | 1978-04-19 |
| JPS6356257B2 (en) | 1988-11-07 |
| IT1094102B (en) | 1985-07-26 |
| AU1304888A (en) | 1988-06-16 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PS | Patent sealed [section 19, patents act 1949] | ||
| PCNP | Patent ceased through non-payment of renewal fee |