FR2475581A1 - SOLID POLYMER ELECTROLYTE AND PROCESS FOR PRODUCING THE SAME - Google Patents

Abstract

CATALYST PARTICLES ARE DEPOSITED IN A HYDROPHILIC THERMOPLASTIC, ION EXCHANGER MATERIAL ON THE PERMIONIC MEMBRANE WITH SOLID POLYMER ELECTROLYTE OR ON A CATALYST SUPPLY CURRENT COLLECTOR. THE ELECTROLYTE BASED ON SOLID POLYMER SO PREPARED IS USEFUL IN ELECTROLYSIS CELLS.

Description

e475581

The invention relates to the field of electrolysis.

Chlor-alkali cells with electrolyte based

solid polymer, especially cells with a membrane

zero spacing mionics, which function like

lules with electrolyte based on solid polymer, have a selective permionic membrane with respect to cations and

separating the anolyte liquor from the catholyte liquor.

In a zero-gap permionic membrane cell, either the anode electrocatalyst is in contact with the surface of the permionic membrane facing the anolyte, or the cathode electrocatalyst is in contact with the surface of the permionic membrane facing the

catholyte. In a cell with poly- electrolyte

solid mother, the anodic electrocatalyst is in

Tact with the surface of the permionic membrane facing the anolyte and the cathode electrocatalyst is in contact with the surface of the permionic membrane facing the catholyte. Electrolytic cells with electrolyte based on solid polymer are generally described in patents BE 872 632; 876 633 and 872 634 while

electrolytic cells with electrolyte based on poly-

solid mother with zero spacing are described in French patent application NO 80.23.765 filed on November 6, 1980 for: "Chlor-alkali electrolytic cell and process with a solid polymer electrolyte."

As described in the patents mentioned above

above, the electrocatalyst is typically embedded and surrounded by a hydrophobic material, for example sintered polytetrafluoroethylene, fluorinated ethylene-propylene or perfluoroalkoxy materials. As described there, the catalyst is in the form of particles embedded in the hydrophobic material. As described elsewhere in

the aforementioned Belgian patents, there is practically no

* - - 35 formation of the permionic membrane during the operation of fixing the catalyst particles, the sulfonyl type membranes described having a softening temperature 7-, re t5OU-i

close to its thermal decomposition temperature.

According to the present invention, there is provided an electrolyte based on solid polymer, which is particularly advantageous, in which at least one element of the pair of electrodes has its active catalyst elements, namely the catalytic particles, wire, mesh, sieve and the like. drowned, supported

or partially surrounded by a deformed portion thermoplastic-

only a hydrophilic material, resistant to the electrolyte.

As hydrophilic materials resistant to the appropriate electrolyte

required, mention may be made of halogenated hydrocarbon polymers characterized by the presence of acid groups, esters or alkali metal salts. According to a preferred embodiment

of the present invention, the hydrophilic polymer is -initial-

a thermally deformable thermoplastic form, from -

the permionic membrane or a thermophilic hydrophilic resin

tick compatible with permionic membrane and particles

The catalyst particles are embedded in the resin while the resin is thermoplastic, while the particles are then surrounded by a deformed portion of the resin. In other words, the resin can be an acid, for example a carboxylic acid or one of its lower alkyl esters,

for example a lower alkyl ester of a carboxylic acid

than. By portion deformed in the thermoplastic state of the resin is meant a portion, for example an area, surface, film, layer or volume of the resin which has been deformed, for example by application of heat or compression or the

two in the thermoplastic form, for example a car-

boxylic, an alkyl ester of a carboxylic acid or an acid chloride of a carboxylic or sulfonic acid, as will be described more fully below, even if the state

resin, for example after depositing the particles

those of catalyst and subsequent hydrolysis, can be rigid, brittle or infusible, such as one of its sodium or

potassium.

The material based on hydro-electrocatalyst-resin

phile can be in the form of a laminate of> 47.55s1

electrocatalyst particles and a hydro resin film

phile on the surface of the permionic membrane. Alternatively, the material based on hydrophilic electrocatalyst-resin may

be in the form of a laminate of electric particles

trocatalyst and hydrophilic resin particles on the

face of the permionic membrane. Alternatively, the electrocata-

lyser may be present in the form of catalytic particles

in and on a deformed portion in the thermoplastic state

that of the resinous material of the permionic membrane. According to yet another embodiment, the electrocatalyst and

the hydrophilic resin can be in the form of a

pot on a wire, mesh or sieve support, held in con-

tact with the permionic membrane with electrode based

solid polymer, i.e. as an electrode of a cell

electrolytic cell with polymer-based electrolyte

solid with zero spacing.

Solid polymer electrolytes considered

according to the invention can be prepared from a compound

sition of a thermoplastic resin, hydrophilic, resistant to

electrolyte and material for electrocatalyst.

According to a preferred embodiment, the composition

is kept in contact with the permionic membrane

above the glass transition temperature of the thermoplastic, hydrophilic, electrolyte-resistant material, this

to obtain from the resin composition and elect

trocatalyst a deposit, a film, a surface or a layer

adhering to the surface of the permionic membrane.

According to another embodiment implemented in a cell with an electrolyte based on solid polymer with zero spacing, the composition of hydrophilic resin and of electrocatalyst is kept in contact with a support or metallic current carrier with open mesh, with sieve or in sheet form so as to produce a

electrode to which electrocata particles adhere

lyser and a hydrophilic resin.

For the practical implementation of the modalities

sages above, the hydrophilic resin resistant to the electrolyte can be in the form of particles, spheres, fragments,

pulverulent and similar materials from, for example,

full of crushing, grinding or pulverizing a

extrudate, film, sheets, strands and the like.

According to another embodiment of the invention, the permionic membrane can be a carboxylic acid or one of its lower alkyl esters or an acid chloride, for example a carboxylic acid chloride or a sulfonic acid chloride and can be made thermoplastic by

view of the deposition of a particulate catalyst thereon.

Chlor-alkali cells with electrolyte based

of solid polymer include an electrolyte based on poly-

solid mother separating the anolyte from the catholyte. The solid polymer electrolyte comprises a permionic membrane with either a cathode electrocatalyst in contact with

its surface facing the catholyte, i.e. an electrocataly-

anodic contactor in contact with the ano-facing surface

lyte, or still a cathodic electrocatalyst in contact

with the surface facing the catholyte and an electrocata-

anodic lyser in contact with the surface facing towards the

nolyte. The electrocatalyst in contact with the membrane

mionique adheres either to the permionic membrane, or to a catalyst support or a current carrier, or to a combination of catalyst support and current carrier maintained in contact with the permionic membrane, that is to say as in a cell with electrolyte based

solid polymer with zero spacing or hybrid cell.

When the electrocatalyst is moved away from the membrane

mionic, the electrocatalyst adheres to a cataly-

or a current carrier or a combination of catalyst support and current carrier such as

in a hybrid cell.

As provided by the invention, the electroca-

talyseur is present and in contact with a hydro-

phile, for example a layer, sheet, film, hydrophilic laminate or a deformed portion of fragments, particles, strands, hydrophilic extrudates and the like or a deformed portion of a layer, sheet, d '' hydrophilic film or laminate. The hydrophilic material is deformed, for example a deformed product

thermally and by compression from a thermal form

moplastic of hydrophilic matter.

The structure of hydrophilic matter and electrocata-

intended lyser is a thin, porous, permeable form or mass

gas bleed and wettable by the electrolyte, present on the permionic membrane or the catalyst support in the form of a film, a sheet, a laminate, a layer

and the like having the properties mentioned above.

is lying. As provided according to the invention, the charge of hydrophilic material on all of the hydrophilic material and of the electrocatalyst in the catalyst film is between approximately 5 and approximately 75% by weight, preferably between

about 10 and about 50% by weight and, in one embodiment

particularly preferred, between about 15 and about

% in weight. In this way we obtain a charge of cat-

lyser from about 0.1 to about 10 mg per cm2 of membrane per-

mionic and a film thickness of about 12 to 380 microns.

Especially preferred is a catalyst charge of approx.

ron 0.5 to 5 mg per cm2 of permionic membrane and a thick-

about 50 to 125 microns film thickness, although thick

thicker or thinner film sisters can be

used without harmful effect.

In an exemplary embodiment, the hydrophilic resin and the electrocatalyst particles are applied to a support, for example a permionic membrane or a catalyst support, under conditions where the resin is thermoplastic, so that deform

and cause adhesion of the electrocataly-

sor on the mass of hydrophilic resin-electrocatalyst,

which in turn adheres to the support.

In an embodiment given by way of

laughing, the electrocatalyst particles are applied directly to a support, for example a membrane

Z475531

permionic acid which is in thermoplastic form, for example a carboxylic acid, a lower alkyl ester of a

carboxylic acid or an acid chloride of a car-

boxylic or of a sulfonic acid under conditions of temperature and pressure where the support is thermoplastic so as to deform and cause adhesion of the

particles of electrocatalyst to the support.

Although, about the hydrophilic resin, it is

question of a thermoplastic resin or a portion

formed of a thermoplastic resin, it should be emphasized that its characterization as a thermoplastic resin

-reports to its condition at the time of manufacture of the elect

trolyte based on solid polymer or catalyst support

that the resin may later lose its character

thermoplastic, for example by hydrolysis

forming into alkali metal salt.

The resins provided according to the invention, namely ion exchange resins selective for cations, have thermoplastic properties, which depend on the substituents linked to the active ion exchange groups, on the presence of ether bonds and the practical absence of crosslinking. For example, resins with degrees

of equal crosslinking and equal concentrations of liai-

  ether sounds are thermoplastic in the ester form, ther-

  moplastics but less in the acid form and substantially

less thermoplastic in the form of an alkali metal salt.

In addition, the higher the concentration of ether bonds,

  the more the resin is thermoplastic and deformable.

  As provided according to the invention, the hydrophilic resin is present in the ester or acid form and preferably in the ester form of a carboxylic acid and in the form of acid chloride for a carboxylic acid or an acid. sulfonic, during the formation of the solid polymer electrolyte. In addition, the resin should have a low content of crosslinking agents, namely lower.

  or equal to that of the permionic membrane resin under

with a high content of ether bonds, i.e.

greater than or equal to that of the permionic membrane under

underlying. When the hydrophilic resin is in the form of an alkali metal carboxylate, it can be converted into the carboxylic acid in hydrogen form, into the carboxylic acid anhydride or, in a preferred embodiment, into

the lower alkyl ester.

For example, the alkali metal carboxylate can be converted to the carboxylic acid by contacting the salt with an acid, for example an aqueous acid solution, in the presence of a suitable polar solvent. As suitable acids, mention may be made of inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid.

  or phosphoric acid among others and organic acids

such as acetic acid, haloacetic acids comprising trihaloacetic acids, for example trichloroacetic acid and trifluoroacetic acid as well as propionic acid among others. The acid is preferably added in the form of an aqueous solution, for example in the form of an aqueous acid solution of 0.5% by weight to 90% by weight and preferably in the form of an aqueous acid solution of 1 to

% in weight.

Suitable solvents are water and solvents

  polar organic, such as methanol, ethanol, ethyl-

  lene glycol, dimethyl sulfoxide, acetic acid, phenol and the like. The polar organic solvent, when it is

  used, is present at a concentration of 5 to 90% by weight.

The reaction is carried out at a temperature of 10 ° C. to 1200 ° C.

  from about 30 minutes to 24 hours.

  Then the carboxylic acid groups can be converted to alkyl ester groups by reaction with

  an alcohol. Desirable alcohols are the lower alcohols

  laughing, namely C1 to C5 alcohols such as methanol, ethanol, propanol, butanol, pentanol and their

isomers.

  Alternatively, the carboxylic acid groups can be converted to acid halide groups or acid anhydride groups with subsequent conversion to esters of acid halide or acid anhydride groups. ''

When the ester is formed from halo groups

carboxylic acid genide, the acid halide can be

  obtained by reaction of the carboxylic acid with trichlo-

phosphorus rure, phosphorus oxychloride, chloro

thionyl rure and the like, after which it is reacted

the acid halide with an alcohol.

  When the ester is formed from anhy-

carboxylic acid, carboxylic acid anhydride can be obtained by reaction of the carboxylic acid group

with an acid anhydride, for example acetate anhydride

that after which the acid anhydride formed is reacted with

an alcohol.

  When the permionic membrane is an a-

sulfonic acid, for example a sulfonic acid or a derivative thereof, in the form of an alkali metal salt, this can be converted into the sulfonyl halide, for example into

sulfonyl chloride, to make the membrane thermoplastic.

The conversion to the sulfonyl halide can be carried out by reaction with SOC12 or PCl5. For example, the acid membrane

  sulfonic acid or its alkali metal salt can be used

tact with PC15 vapor or with a solution of PC15,

for example PCl5 in POC13> or in POC13 and an organic solvent

such as a halohydrocarbon. Halohydrocarbon solvents

  suitable bonés are trichlorethylene, perchlorethy-

lene, 1,1,2-trichloroethane, 1,1,2,2-tetrachloroethane and 1,2difluoro-1,1,2,2-tetrachloroethane. The report of

PC1 on POC13 or on POC13 plus halohydrocarbon solvent -

  is between about 0.01 and about 1.6 and preferably between about 0.25 and about 1. In general, the time required for the conversion of sulfonic acid or

its salt in acid chloride is at least 8 hours

  at the atmospheric boiling point of the PC15 solution. Alternatively, the membrane based on sulfonic acid C47558 i or its alkali metal salt is brought into contact with SOC12 to form the acid chloride. This is done by reflux heating with SOC12 for a sufficient time

  to form the acid chloride, for example at least 8 hours

  res approximately and preferably approximately 16 to 48 hours. The application of the electrocatalyst particles to the hydrophilic thermoplastic resin and the application of the hydrophilic resin and the electrocatalyst to the support or substrate take place at high temperature and under pressure

  to make the resin flowable, deformable, sticky or partially

partially melted and then deform the resin with the

  particles incorporated so as to adhere the deformed portion and the catalyst particles to the substrate. Range

of temperature considered is high enough to give

  Give the hydrophilic resin a volumetric flow rate greater than approximately 0.1 mm 3 / second but below the temperature of

  thermal decomposition of the resin. The temperature required

  to provide the above-mentioned volumetric flow rate is functional

  tion of the ether linkages in the resin, the substituents in the resin, the rate of crosslinking and the degree of polymerization and can be determined by routine testing. From a practical point of view, this temperature

is at least 1200C and is generally between approxi-

ron 130'C and around 150'C.

The pressure required to deform the resin and deposit the electrocatalyst particles is at least

  About 1 kg per cm2 and is preferably between approx.

  ron 1 kg / cm2 and about 300 kg / cm2 although pressures su-

  can be used.

The pressure and the temperature are maintained until the particles of electrocatalyst are fixed in the resin and the mass of resin and electrocatalyst adheres to the support, for example between approximately 1 minute and

about 5 hours.

  Specific combinations and permutations of

time, temperature and pressure within specified limits

ties depend on the resin and the size of the electrocatalyst particles and can be determined by

routine testing.

  Hydrophilic thermoplastic resin used to

  the adhesion of the electrocatalyst to the support and to

  To provide a hydrophilic bed may be, for convenience, the same ion exchange material based on halogenated hydrocarbon as the underlying permionic membrane. When the

  hydrophilic thermoplastic resin differs from the per-

underlying ionic, the thermoplastic resin may have a lower glass transition temperature than the underlying permionic membrane for a volumetric flow

given, as described above. Alternatively, the hydro-

  phile and the underlying permionic membrane may have

der of similar halocarbon skeletons, differing in

  selective substituents with respect to ions or by properties

  physical tees, for example thermoplastic properties

  or by both. However, the hydrophilic thermoplastic resin

tick considered is a halogenated hydrocarbon polymer, preferably a fluorinated hydrocarbon comprising groups

  ion exchangers, selective with respect to cations, immobi-

them on a halocarbon skeleton.

  The permionic membrane sandwiched between the anolyte

  and the catholyte is also a poly- halogenated hydrocarbon

  mother with ion-exchange groups, selective for

  live cations, motionless on a halocarbon skeleton. The membrane can be from about 50 to about 250 microns thick although thicker or thinner permionic membranes can be used. This provides an electrolyte based on solid polymer having a thickness of about 75 microns to about 1000 microns (or 1 mm). The

permionic membrane can be a laminate of two sheets-

  membranes or more. In addition, it may include

internal reinforcement bres.

The permionic membrane as well as the hydro-

philes can be copolymers (1) of a fluoro polyether

  rovinyl having pendant ion exchange groups

and corresponding to formula (I).

I) CF2 = CF-Oa- [(CF2) b (CX'X ") c (CFX ') d (CF2-O- (X'X") e (CX "X'O-CF2) f] -A where a is O or 1, b is O to 6, c is O to 6, d is O-to 6, e is O to 6, f is O to 6; X, X 'and X "

  are -H, -C1, -F and - (CF2) gCF3; q is 1 to 5, [] is an ar-

discretionary ranking of fractions and A is the group é-

  ion changer during as will be described below.

Preferably a is 1 and X, X 'and X "are -F and (CF2) gCF3.

  Fluorovinyl polyether can be poly-

  merited with (II) a fluorovinyl compound (II) CF2 = CF-Oa- (CFX "d) -A and (III) a perfluorinated olefin

(III) CF2 = CXX '

or (I) can be copolymerized with only one per-

  fluorinated (III) or (I) can be copolymerized with only

a perfluorovinyl compound (II).

  The ion exchange group is a selected group

  tif vis-à-vis cations.It can be a phosphonic group,

a phosphoric group, a sulfonic group, a car-

  boxylic, one of their precursors or their reaction products, for example an ester. We prefer groups

  carboxylates, their precursors and their reaction products

  tion. As provided by the invention, A is pre-

Ference chosen from the groups:

- COOH,

- COOR1,

- COOM,

* - COF,

- COC1,

- CN,

-CONR2R3,

- SO3H,

- S03M

- S02F, and

- SO2C1

o R1 is a C 1 to C alkyl group O, R2 and R3 are hydrogen or C1 to C10 alkyl groups and M is an alkali metal or a quaternary ammonium group. According to a particularly preferred embodiment, A is -COF, -COCli,

-COOH,

-COOR1,

-S02F, or -S02Ci

o R is C1 to C5 alkyl.

The permionic membrane considered has a capacity

ion exchange city of approximately 0.5 to approximately 2 milliequiva-

slow per gram of dry polymer, preferably from about 0.9 to about 1.8 milliequivalents per gram of dry polymer and, in a particularly preferred embodiment, it is between about 1 and about 1.6 milliequivalents

per gram of dry polymer. The permionic membrane considers

rée has a volumetric flow of 100 mm3 per second at

a temperature of 150 to 300 C and preferably at a temperature

strikes between 160 and 250 C. The transition temperature

the polymer of the permionic membrane is located in

below 70 C and preferably below about 50 C.

The planned permionic membranes can be pre-

trimmed by the methods described in U.S. Patent 4,126,588

to which a person skilled in the art can refer if necessary.

Although the hydrophilic hydrocarbon resin used in combination with the electrocatalyst is deemed to be constituted by an ion exchange material, it goes without saying

that the resin can be more elastic and more thermoplastic

that the ion exchange material used to manufacture

tion of the permionic membrane. As it was envisioned,

the hydrophilic resin has a substantial volumetric flow rate-

equal to or greater than that of the permionic membrane,

a temperature for a given volumetric flow which is in-

lower than or equal to that of the permionic membrane and a glass transition temperature which is less than or equal to that of the permionic membrane. The increased ability to extrude, form or deform the hydrophilic resin, when these properties exist, is such that it

-2475581

allows its deformation during the manufacture of the elect

trolyte based on solid polymer while ensuring

less formation of the underlying permionic membrane.

This can be achieved by adding plasticizers or by reducing the rigidity of the chain or by both

at a time. By reduced chain stiffness is meant the ef-

fet observed with short side chains having

for example ether bonds, compared to chat-

longer side tubes with fewer ether bonds.

As envisioned, the hydrophilic resin which binds

catalyst particles at the permionic membrane or at the sup-

catalyst port has an ether bond content at

less equal and preferably greater than the content of liiai-

ether sounds of the permionic membrane. The content of ether bonds in the hydrophilic resin can be increased by providing fractions of formula (IV) CF2 = CFOR4 in the polymer, where R4 is a perfluoroalkyl radical from C1 to C5. Resin

hydrophilic is preferably applied to the per-

mionic or on the catalyst support in the form of an ester, for example in the form of a methyl alcohol ester,

ethyl alcohol, butyl alcohol or propyl alcohol

than. Alternatively, it can be applied to the membrane or to the current carrier in the acid form or in the form of an acid halide. However, the form of

alkali metal salt does not have sufficient volumetric flow in the molten state to allow its use.

As foreseen by the invention, the permionic membrane

underlying as well as the hydrophilic resin are copoly-

mothers which may contain: (I) fluorovinyl ether-acid fractions, derived from: CF = CF-O- {CF2) b (CX'X ") (CFX ') (CF2-O-cx'X") e (CX 'X "-O-CF2) 1A, illustrated by

CF2 = CFOCF2CF (CF3) OCF3CF2CF2COOOCH3,

CF2 = CFO (CF2) 330CFCOOCH3,

CF

CF2 = CFO (CF2) 40OFCOOCH3,

CF3 CF2 = CFOCF2CFCF2COOCH3, and CF3 CF2 = CFOCF2CF (CF3) OCF (COOCH3 CF3, among others (II) fluorovinyl fractions derived from

CF = CF- (O) - (CFX ') -A,

2 a CXdA illustrated by

CF2 = CF (CF2> 2-4C00CH3 TO

CC

1 CF2 = CF (CF2) 2_4COOCH3,

CF2 = CFO (CF2) 2-4C0OCH3

CF2 = CFO (CF2) 24C0C2H5, and CF2 = CFO (CF2) 2_4C00CH3, among others (III) fractions based on fluorinated olefin derivatives

CF2 = CXX '

of

as illustrated by tetrafluoroethylene, trichloro-

fluoroethylene, hexafluoropropylene, trifluoroethylene, vinylidene fluoride and the like and (IV) vinyl ethers derived from

CF2 = CFOR4,

the content of ether bonds of the hydrophilic resin being

equal to or greater than the content of ether bonds in the mem-

underlying permionic brane.

Although the above resins are illustrated by

esters of carboxylic acid, it will be noted that one can also

Also use sulfonyl halide resins, for example sulfonyl chloride resins, capable of

thermoplastic behavior.

The hydrophilic thermoplastic resin supporting the

electrocatalyst can be distinct from the permionic membrane

that underlying. In other words, it may not be a deformed surface of the underlying permionic membrane, but may be a laminate, laminate, film or the like, deposited thereon, bonded or adhered to another

way to the permionic membrane.

In one embodiment, the hydrophilic resin and

the electrocatalyst particles are present on the mem-

permionic bran in the form of a bound, thin, porous mass, permeable to gases and wettable by the electrolyte. The hydrophilic resin and the electrocatalyst form a film, a layer

che, sheet, laminate or surface which is in con-

tact with the permionic membrane and can be drowned or enro-

open in it or even be linked to it.

In an alternative embodiment, the particles of

electrocatalyst is found in and on a portion deformed in the thermoplastic state of the permionic membrane, namely

as when the permionic membrane is in the thermal state

moplastic during the adhesion of the particles and that the mem-

brane is then hydrolyzed to a metal salt form

alkaline infusible.

In another alternative embodiment, the hy-

drophile and the electrocatalyst particles are linked to a mesh, a sieve or a perforated metal film, which serves, for example, as a catalyst support and as a current collector. The electrocatalytic particles and the hydrophilic resin are present on the metallic structure in the form of a sheet, a layer, a film, a fabric or the like, thin, porous, permeable to gases and wettable by the electrolyte. , by covering individual fibers

or strands or by making the connection between fibers ad-

and strands of the current collector or support

of catalyst. The fine mesh rests on the per-

Mionic. According to another alternative embodiment, the electrolysis cell can be a hybrid electrolytic cell with a zero-spacing electrode as described above.

and an electrode bound and embedded in the membrane.

Various electrocatalysts can be used with advantage. The electrocatalysts can for example be graphite, fluorinated graphite, metals and various metallic compounds. The electrocatalyst particles are preferably fine mesh particles, for example particles

less than 0.15 mm. Particularly preferred are

cules less than 0.044 mm. These fine particles, for example nickel particles smaller than 0.044 mm, can be pyrophoric and require treatment in organic solvents, for example in alcohols,

ketones, ethers and the like or in water.

A group of particular anode electrocatalysts

highly satisfactory includes oxides of metals of the platinum group, especially oxides with a specific area

increased. Alternatively, the oxides of metals of the platinum group

tine may be present with oxides or oxidized compounds of other metals. Other metal oxides can

be oxides of titanium, tungsten, tantalum, nio-

bium, vanadium and the like. Second metal oxide

may be present as powders or particles

conductors of a low chlorine overvoltage or in the form of

mixed crystals, inter-metallic oxides, oxy-

intermetallic dice and the like, with metal oxides

of the platinum group.

A group of particularly advanced electrocatalysts

tagging which can be used with hydrophilic resins pre-

seen according to the invention are the thermal decomposition products

platinum group metal halide mique, e.g.

ple ruthenium, iridium and ruthenium-iridium alloys.

These catalysts are prepared by thermal decomposition of

halides under oxidizing conditions, followed by a frag-

mentation, washing, reduction, for example with hydrogen or carbon monoxide and fragmentation

complementary and washing.

The cathode electrocatalysts are preferably porous particles of transition metals, for example iron, cobalt, nickel and the like. In addition, others

substances may be present there, for example molyb-

dene with nickel to stabilize the characteristics

hydrogen overvoltage of nickel. Electro- particles

porous cathodic catalysts can be prepared by

conventional means.

As described above, the catalysts are typically applied by shaping

of a composition of the thermoplastic resin and of particu-

those of catalyst. The resin may be in the form of a mass

fragmented, extrudate or the like. After that, the com-

position is made thermoplastic and is applied to the support, namely the permionic membrane or the catalyst support. According to a particularly preferred embodiment, an electrolyte based on solid polymer is prepared having an anodic surface of an ion exchange resin based

perfluorinated carboxylic acid with grit particles

phite, a cathode surface of an ion exchange resin

based on perfluorinated carboxylic acid with, inside,

porous nickel cules and, in between, a per-

selective perfluorinated mionic with respect to cations.

According to the embodiment considered, a composition is prepared containing three parts of graphite for

a part of perfluorinated carboxylic acid. This is

lined on a permionic membrane with a thickness of 250 mi-

crons approximately and heated to 210 ° C for 10 minutes under a pressure of about 20 kg / cm. A composition of ten parts of a mixture of 60% by weight of fine particles of

iron and 40% by weight of fine particles of nickel is met

dipped with a part of fine particles of exchanging resin

ion geuse based on perfluorinated carboxylic acid and is applied to the opposite surface of the permionic membrane, by heating for 10 minutes at 200 ° C. under a pressure of

200 kg / cm2.

The solid polymer electrolyte thus prepared

is placed in an electrolytic cell between a collection

titanium mesh anode current tester and a collector

cathode current with copper mesh. The electrolysis

abuts with an anolyte liquor based on sodium chloride

aqueous and a catholyte liquor based on sodium hydroxide

aqueous dium, in which case chlorine is released on the surface

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anodic electrolyte based on solid polymer,

hydrogen is released on the cathode surface of the electro-

lyte based on solid polymer and hydroxyl ion is formed

in the catholyte.

According to an alternative embodiment, a

electrolyte based on solid polymer by providing a mem-

brane ion exchange based on perfluorinated carboxylic acid

inserted and in contact with an anodized catalyst support

that on one of its faces and a cathode catalyst support

than on the opposite side.

As provided according to the invention, each of the cathode supports has a film, a sheet, a layer

or a thin, porous, gas permeable and wet coating

ble by the electrolyte on the wires, strands or filaments indi-

of the catalyst support with possibly a

some bridging between them.

Depending on the embodiment considered,

adorns a composition containing five parts of fine particles of a rutile-type crystalline material containing ruthenium and titanium oxides and one part of particles

fines of an ion exchange material based on carboxy-

perfluorinated liquor. This is applied to a camera support

titanium grid talyser with a mesh of 10 filaments per 25 mm x ten filaments per 25 mm, each filament having

a diameter of 0.75 mm and an open area of approximately 50%.

The composition is pressed into the mesh under a pressure of approximately 175 kg / cm 2 and at a temperature of 200 ° C. for minutes.

Depending on the embodiment considered,

adorns a composition containing 5 parts of fine particles of grade 316 stainless steel attacked by NaOH and 1 part of ion exchange resin based on methyl ester of a perfluorinated carboxylic acid. This is applied to a mesh grid of stainless steel wire with a

mesh of 8 filaments per 25 mm x 8 filaments per 25 mm, each

that filament having a diameter of 0.75 mm and a surface

65% pledge. The mesh grid and composition are

heated to around 200 ° C for 20 minutes under a pressure

150 kg / cm2 in order to produce a cathode.

The zero-gap permionic membrane cell

which works like an electrolytic cell with electro-

lyte based on solid polymer is assembled by compression of a permionic membrane between anode and cathode elements prepared as described above. Electrolysis can

then be undertaken with a sodium chloride brine

dium as anolyte and aqueous sodium hydroxide as

catholyte.

The following examples are illustrative and in no way limitative.

Example I

An anode element with poly-electrolyte

solid mother was prepared by simultaneous deposition of an electro-

catalyst and a thermoplastic ion exchange material

that, based on perfluorinated carboxylic acid, on a membrane

permionic based on perfluorinated carboxylic acid.

The anode was prepared by mixing 4.5 g of graphite powder having a particle size less than 0.044 mm

as an anode electrocatalyst and 1.5 g of exchangeable material

crushed ion geuse, based on perfluorinated carboxylic acid,

in the acid form.

This was applied to a permionic membrane based on perfluorinated carboxylic acid with a thickness of 0.25 mm and heated for 10 minutes at 2000C and under a pressure of kg / cm The current conductor was titanium coated with a platinum-tin-ruthenium alloy and supported

on the solid polymer electrolyte.

The potential for release of anodic chlorine has been

measured in saturated brine at pH = 2. The results are in-

shown in Table I below:

TABLE I

Release potential Current density of anodic chlorine per Ampere / m2 compared to Ag / AgCl

1.17 2150

1.22 4300

1.24 6450

1.29 8600

1.32 10750

Example II

An anode element with poly-electrolyte

solid mother was prepared by simultaneous deposition of an electro-

catalyst and ion exchange material, thermoplastic

that, based on perfluorinated carboxylic acid, on a support

of titanium mesh catalyst.

The anode was prepared by mixing 10 g of powder

graphite having a particle size less than 0.044 mm, im-

pregnated with palladium-tin-ruthenium alloy as electro-

anodic catalyst and 20 g of ground ion exchange material based on perfluorinated carboxylic acid, in the form

acid.

This was applied to a cataly-

titanium mesh switcher with an opening of 0.177 mm and a gauge of 0.13 mm. The coated titanium mesh was heated for 10 minutes at 210 ° C. under a pressure of 170 kg / cm 2. The potential for release of anodic chlorine was measured in saturated brine at pH = 2. The results are shown in Table II below:

TABLE II

Release potential Current density of anodic chlorine per Amperes / mt

compared to Ag / AgCl -

1.16 7526

1.17 4300

1.19 6450

1.24 8600

1.30 10750

Example III A cathode element with an electrolyte based on

solid polymer was prepared by simultaneous deposition of an

trocatalyst and an ion exchange material, thermoplas-

tick, based on perfluorinated carboxylic acid, on a support

of metal catalyst.

The cathode was prepared by mixing 3 g of grade 316 stainless steel having a particle size of less than 0.044 mm in water as a cathode electrocatalyst and 2 g of ground thermoplastic ion exchange material,

based on perfluorinated carboxylic acid, in the acid form.

This was applied to a cataly-

0.15 mm mesh and 0.13 mm gauge copper sieve supported on a permionic membrane based on perfluorinated carboxylic acid, having a thickness of 0.25 mm and was heated for 10 minutes at 2000C under a pressure of 125 kg / cm The resulting cathode element with electrolyte based on solid polymer was then evaluated as a cathode in aqueous NaOH at 25% by weight. The cathodic potential with respect to an Ag / AgCl reference electrode was

* 1.53 volt at 2150 Amp./m2.

Example IV

A cathode element with electrolyte based on

solid polymer was prepared by simultaneous deposition of a

electrocatalyst and an ion exchange material, ther-

moplastic, based on perfluorinated carboxylic acid on a

metal catalyst support.

The cathode was prepared by mixing 3 g of mixed metal powder having a particle size less than 0.044 mm, containing 58% by weight of iron powder and 42%

by weight of nickel powder as cathode electrocatalyst

0.3 g of thermoplastic ion exchange material

that, ground, based on perfluorinated carboxylic acid, under the

acid form.

This was applied to a copper catalyst support of 0.177 mm mesh opening and a caliber of 0.13 mm, supported on a permionic membrane based on fluorinated carboxylic acid of 0.25 mm thick and was heated for 10 minutes at 200 C under a pressure of

kg / cm2.

The resulting cathode unit with solid polymer electrolyte was then evaluated as a cathode in

25% by weight aqueous NaOH. The cathodic potential compared to

port to an Ag / AgCl reference electrode was 1.41 volts

at 2150 Amp./m2.

Example V

  A cathode element with electrolyte based on

solid polymer was prepared by simultaneous deposition of an electro-

catalyst and ion exchange material, thermoplastic

  that, based on perfluorinated carboxylic acid, on a support of

metallic catalyst.

The cathode was prepared by mixing 3 g of a powder prepared by attacking a 316 stainless steel powder, with a particle size less than 0.044 mm, in aqueous NaOH at 70% by weight for 116 hours at 150 ° C. with subsequent washing in dilute HCl as electrocatalyst

  cathodic and 0.3 g of ion exchange material thermo-

  plastic, crushed, based on perfluorinated carboxylic acid,

in the acid form.

This was applied to a cataly-

  copper seur having a mesh opening of 0.177 mm and a gauge of 0.13 mm and heated for 10 minutes at 'C under a pressure of 125 kg / cm The resulting cathode element, with electrolyte based on solid polymer, was then evaluated as a cathode in 25% by weight aqueous NaOH. The cathodic potential with respect to an Ag / AgCl reference electrode was 1.34 volts at 2150 Amp./m Although the invention has been described by some

  of its preferred embodiments and examples illus-

  However, it should be noted that the invention should in no way be limited to them and that embodiments presented in the form of a variant or equivalent fall within the scope of the invention.

part of the invention.

Claims (14)

R E V E N D I C A T IONS 1. Electrolytic cell divided into two compartments electrolyte by an electrolyte-based polymer   solid, said electrolyte based on solid polymer comprising   both a permionic membrane with a pair of electrodes   anodic electrocatalyst in contact with one of its sur-   faces and of cathode electrocatalyst in contact with its opposite surface, said cell being characterized in that at least one element of said pair of electrodes comprises   electrocatalyst particles adhering to a portion   formed in the thermoplastic state of an exchange material ion, hydrophilic, fluorinated.   2. electrolysis cell according to claim 1,   characterized in that the hydro-ion exchange material   phile fluorinated is a deformed portion in the thermoplastic state- permionic membrane tick. -   3. Electrolysis cell according to one of the claims   1 or 2, characterized in that the electrode comprises a catalyst support resting on the permionic membrane and comprising a particulate material as electrocatalyst as well as a hydrophilic fluorinated ion exchange material,   said fluorinated ion exchange material adhering to the material of the electrocatalyst in particles and with the support of   talyseur. 4. Electrolysis cell according to any one of   Claims 1 to 3, characterized in that the material   hydrophilic ion exchange is a deformed portion at   the thermoplastic state of a resin chosen from the resi   Carboxylic acid resins, alkyl esters of al-   lower cools and carboxylic acid, halo resins   sulfonyl genide and carid acid halide resins boxylic. 5. Method for obtaining an electrolyte based on solid polymer comprising a permionic membrane with an electrocatalyst adhering to one of its surfaces, said   process of keeping the electrocatalyst in contact tact with the permionic membrane at a temperature and under 54755o 1 a high pressure so as to ensure the adhesion between   these, and being characterized in that it consists in main- keep the electrocatalyst in contact with an exchanging material   ion geuse, hydrophilic, thermoplastic, at a temperature and under a pressure sufficient to deform the material   ion exchange, hydrophilic, thermoplastic. 6. Method according to claim 5, characterized in what the ion-exchange, hydrophilic, thermoplastic material   tick is the permionic membrane and it consists in putting   the surface of the permionic membrane in contact with the elect   trocatalyst at sufficient temperature and pressure to deform the permionic membrane, so that ensure adhesion of the electrocatalyst to the membrane Mionic.   7. Method according to one of claims 5 or 6, characterized in that the hydrophilic ion exchange material   thermoplastic is selected from car- boxylic, alkyl ester resins of lower alcohols and carboxylic acids, acid halides of carboxylic acid resins and acid halides of sulfonyl resins. 8. Method according to any one of the claims   to 7, characterized in that a composition of e-   electrocatalyst and ion exchange material, thermoplas- tick, hydrophilic and that the composition is deposited on the permionic membrane. 9. Method according to any one of the claims   to 8, characterized in that the hydrophilic thermoplastic ion exchange material is in the form of particles or of an extrudate.   10. Process for obtaining a catalyst support   sor for an electrolytic cell with electrolyte based on solid polymer, comprising a permionic membrane with an electrocatalyst in contact with one of its surfaces and   supported by a catalyst support, said process consists   both to deposit the electrocatalyst on the cataly- and being characterized in that it consists in depositing said electrocatalyst and a hydrophilic thermoplastic ion exchange material on the catalyst support   at a temperature and pressure sufficient to form the ion exchange material, thermoplastic, hydro- philei so as to cause adhesion of the electrocatalyst to the ion-exchange material, thermoplastic hydrophilic, and that of the ion exchange material, ther-   moplastic, hydrophilic, on the catalyst support. 11. Method according to claim 10, characterized in that the ion exchange material is chosen from carboxylic acid resins of halogenated hydrocarbon, carboxylic acid lower alkyl ester resins than halogenated hydrocarbon, the acid halides of halogenated hydrocarbon carboxylic acid sines and ha-   acid casings of hydrocarbon sulfonic acid resins. halogenated bure. 12. Method according to one of claims 10 and 11,   characterized in that an electro- hydrophilic ion exchange material and catalyst moplastic and in that the composition is deposited on the support catalyst port. 13. Method according to any one of the claims to 12, characterized in that the hydrophilic thermoplastic ion exchange material is in the form of particles or extrudate. 14. Method according to any one of the claims to 13, characterized in that the catalyst support is metallic.