US3884777A - Electrolytic process for manufacturing chlorine dioxide, hydrogen peroxide, chlorine, alkali metal hydroxide and hydrogen - Google Patents

Electrolytic process for manufacturing chlorine dioxide, hydrogen peroxide, chlorine, alkali metal hydroxide and hydrogen Download PDF

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US3884777A
US3884777A US429998A US42999874A US3884777A US 3884777 A US3884777 A US 3884777A US 429998 A US429998 A US 429998A US 42999874 A US42999874 A US 42999874A US 3884777 A US3884777 A US 3884777A
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compartment
alkali metal
anode
chloride
cathode
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Cyril J Harke
Jeffrey D Eng
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Occidental Chemical Corp
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Hooker Chemicals and Plastics Corp
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Priority to BR10588/74A priority patent/BR7410588D0/pt
Priority to CA216,840A priority patent/CA1043736A/en
Priority to JP751086A priority patent/JPS5322960B2/ja
Priority to FI3769/74A priority patent/FI376974A/fi
Priority to FR7443249A priority patent/FR2256263B1/fr
Priority to SE7416364A priority patent/SE409884B/xx
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    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B1/00—Electrolytic production of inorganic compounds or non-metals
    • C25B1/01—Products
    • C25B1/28—Per-compounds
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B1/00—Electrolytic production of inorganic compounds or non-metals
    • C25B1/01—Products
    • C25B1/24—Halogens or compounds thereof
    • C25B1/26—Chlorine; Compounds thereof
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B1/00—Electrolytic production of inorganic compounds or non-metals
    • C25B1/01—Products
    • C25B1/28—Per-compounds
    • C25B1/29—Persulfates
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B1/00—Electrolytic production of inorganic compounds or non-metals
    • C25B1/01—Products
    • C25B1/34—Simultaneous production of alkali metal hydroxides and chlorine, oxyacids or salts of chlorine, e.g. by chlor-alkali electrolysis
    • C25B1/46—Simultaneous production of alkali metal hydroxides and chlorine, oxyacids or salts of chlorine, e.g. by chlor-alkali electrolysis in diaphragm cells

Definitions

  • ABSTRACT Chlorinedioxide, hydrogen peroxide, chlorine, alkali metal hydroxide and hydrogen are produced from alkali metal chloride, alkali metal chlorate, sulfuric acid and water, utilizing an electrolytic cell having anode and cathode compartments separated by two intermediate buffer compartments, the boundaries between the anode and cathode compartments and the buffer compartments being of cation-active permselective membranes which are resistant to attack by the medium and the buffer compartments being separated by 52 U.S. Cl.
  • Chlorine dioxide, hydrogen peroxide, chlorine, and salt-free aqueous alkali metal hydroxide are chemicals that are frequently employed in pulp mill operations, especially for the pulping of wood chips and bleaching of wood pulps. It has long been desired, for reasons of economy and convenience, to'prepare these chemicals together at a single site, preferably adjacent to the pulp mills.
  • the known methods of producing each of these chemicals require comparatively costly and complex apparatuses and multiplicities of reaction stages, so that single-site productions of these reagents has heretofore proved impractical.
  • aqueous alkali metal chloride is electrolyzed to the chlorate, which is treated with hydrogen chloride to form chlorine and chlorine dioxide, which are separated by treatment with water in an absorption tower.
  • This process employs a very slow countercurrent contact of chlorate solution and hydrogen chloride so-that, in addition to an electrochemical cell, the procedure requires a costly array of cascading reactors with a large storage tank for holding the chlorate solution prior to its reaction with hydrogen chloride [see the article by W. H. Rapson, Canadian Journal of Chemical'Engineering Vol. 36, p. 6 (1958)].
  • this process does not produce hydrogen peroxide or a substantially salt-free alkali metal hydroxide, i.e., aqueous sodium hydroxide containing less than about one percent of alkali metal chloride.
  • the present invention provides a novel method, utilizing a relatively simple reaction apparatus, for co-producing chlorine dioxide, hydrogen peroxide, chlorine, substantially chloridefree alkali metal hydroxide solution and hydrogen, from aqueous alkali metal chlorate, aqueous alkali metal chloride, sulfuric acid, water and electric power.
  • This method comprises electrolyzing in a cell having an B to the cathode compartment through M sulfuric acid is oxidized at the anode to produce a sulfuric acid solution of persulfuric acid in the anode compartment, hydrogen chloride and aqueous chlorate anions are reacted to produce chlorine and chlorine dioxide in B, and water and aqueous alkali metal cation are reacted at the cathode to produce aqueous, substantially alkali metal chloride-free alkali metal hydroxide and hydrogen in the cathode compartment, after which the persulfuric acid solution, chlorine dioxide, chlorine, hydrogen and aqueous alkali metal hydroxide are removed from the cell compartments. Subsequently, the aqueous persulfuric acid solution is converted to sulfuric acid and hydrogen peroxide.
  • the FIGURE is a schematic diagram of a fourcompartment electrochemical cell for converting water, alkali metal chloride, alkali metal chlorate and sulfuric acid to chlorine dioxide, chlorine, aqueous alkali metal hydroxide, hydrogen and persulfuric acid.
  • FIGURE also includes hydrolysis means for converting anode compartment with anode therein, a cathode each other by an anion-active permselective membrane, M, solutions resulting from feeding sulfuric acid to the anode compartment and alkali metal chloride and alkali metal chlorate to B", so that with the passage of electric current through the cell hydrogen ,ion selectively diffuses or passes from the anode compartment to B through M chloride and chlorate anions selectively diffuse or pass from B to B through M" and alkali metal cations selectively diffuse or pass from the persulfuric acid to hydrogen peroxide by reaction with water in the form of steam.
  • hydrolysis means for converting anode compartment with anode therein, a cathode each other by an anion-active permselective membrane, M, solutions resulting from feeding sulfuric acid to the anode compartment and alkali metal chloride and alkali metal chlorate to B", so that with the passage of electric current through the cell hydrogen ,ion selective
  • FIGURE the points of addition and withdrawal of typical and preferred reactants and products are illustrated.
  • sodium hydroxide solutions using sodium chloride and sodium chlorate reactants is illustrated, other alkali metal cations, such as potassium, may also be employed.
  • hydrolysis means illustrated is a steam distillation apparatus, it will be appreciated that other suitable vessels or apparatuses for reacting the persulfuric acid solution with water can also be used.
  • electrolytic cell 11 includes outer wall 13, anode l5, cathode l7 and conductive means 19 and 21 for connecting the anode and the cathode to sources of positive and negative electrical potentials, respectively.
  • a cation-active permselective membrane M" 23 Inside the walled cell a cation-active permselective membrane M" 23, anion-active permselective membrane M 25, and cation-active permselective membrane M 27, divide the volume into an anode or anolyte compartment 29, a buffer compartment B 31, a buffer compartment B 33, and a cathode or catholyte compartment 35.
  • Aqueous sulfuric acid is fed to the anode compartment through line 37.
  • Aqueous sodium chlorate and aqueous sodium chloride are fed to B through line 39 and water is fed to the cathode compartment through line 41.
  • sulfuric acid in the anode compartment is oxidized at the anode to form persulfuric acid which is withdrawn as an aqueous sulfuric acid solution through line 43.
  • hydrogen ions selectively diffuse or pass from the cathode compartment through cation-active membrane M into buffer compartment B while chlorate and chloride anions selectively pass from buffer compartment B through anion-active membrane M into buffer compartment B.
  • the aqueous hydrogen chloride introduced by the aforementioned diffusion processes reacts with the chlorate anions to produce chlorine dioxide and chlorine, which are withdrawn through line 45.
  • sodium cations selectively diffuse from buffer compartment B through cation-active membrane M into the cathode compartment where they are reacted with water to form hydrogen, which is withdrawn through line 47, and aqueous sodium hydroxide, which is withdrawn through line 49.
  • the aqueous sulfuric acid solution of persulfuric acid which is recovered from the anode compartment is fed to a steam distillation apparatus 51 and is hydrolytically distilled with steam fed to the apparatus through line 53.
  • the resulting steam distillate, an aqueous hydrogen peroxide solution is withdrawn from the steam distillation apparatus through line 55 and the steam distilland, an aqueous sulfuric acid, is withdrawn from the apparatus through line 57.
  • Equation (1) the overall electrolytic cell reaction is represented by Equation (1),
  • Equation (2) Equation (2)
  • the anode compartments of the cell are charged with sufficient sulfuric acid, in aqueous solution, as to initiate the electrolytic oxidation of the H 80, to H S O while the buffer compartments are charged with sufficient alkali metal chlorate and/or alkali metal chloride, also in aqueous solution, to avoid depletion and concentration polarization. Additionally, an aqueous solution containing about 0.1 to 1 percent of alkali metal hydroxide is charged into the cathode compartments.
  • the cell is filled so as to provide a small free space, e.g., about 1 to 10 percent, preferably 1 to percent of the cell volume, above the compartments so as to facilitate collection and withdrawal of the gaseous products, chlorine dioxide, chlorine and hydrogen.
  • sulfuric acid, alkali metal chlorate and alkali metal chloride are fed to the cell at rates sufficient to establish concentrations which will effect the electrolysis according to Equation (1).
  • these will be in molar proportioned rates, of about 2:1:l, with the usual variance from these of about :20 percent, preferably percent and most preferably about :2 percent.
  • electrolysis water is charged at a sufficient rate to maintain the desired caustic concentration.
  • the cell is operated at a temperature above the freezing point of the liquid contents of the cell, i.e., above about 2 to 5C. and below about 60C. or the temperature at which the rate of electrolytic formation of persulfuric acid from sulfuric acid is about equal to the rate of hydrolytic decomposition of the peracid.
  • the cell is operated at a temperature of about 5 to 40C., more preferably at about to 35C. and most preferably at about to C.
  • the sulfuric acid charged to the anode compartment is generally aqueous sulfuric acid containing at least about 80 percent by weight sulfuric acid and is preferably concentrated sulfuric acid, aqueous sulfuric acid containing about 90 to 100 percent, usually 93 to 97 percent sulfuric acid. If desired and useful, stronger,
  • the alkali metal chloride and alkali metal chlorate are generally charged in aqueous solution or solutions at concentrations of from about 1 Normal up to about the saturation solubility of the salts. Preferably the con centrations of the aqueous alkali metal chlorate charged are about 3 N.
  • the chlorate and chloride salts may be charged in individual feed streams to compartment B but preferably the salts are charged in the same feed solution.
  • the sulfuric acid solution of persulfuric acid produced in the anode compartment is reacted with water at about 60 to 100C, preferably at about 100C, to produce hydrogen peroxide, in accord with known processes for the hydrolytic conversion of persulfuric acid to hydrogen peroxide.
  • At least about two molar portions of water per mol of persulfuric acid are employed in the hydrolysis in accord with the stoichiometry of Equation (2) above.
  • the water is charged in excess, e.g., 10 to 300 percent or 20 to 100 percent.
  • the water which is charged to the hydrolysis operation is in the form of steam.
  • the persulfuric acid solution is subjected to steam distillation to prepare hydrogen peroxide, the distillation being effected in a steam distillation apparatus comprising a still and a condenser of the types conventionally used for the manufacture of hydrogen peroxide from persulfuric acid.
  • the hydrogen peroxide is recovered from i the steam distillation apparatus as an aqueous steam distillate, with the concentration of the hydrogen peroxide in the distillate being determined by the amount of water used in the steam distillation.
  • the proportion of water may be regulated to produce the peroxide in best form for use, e.g., in bleaching, especially of woodpulps.
  • the distilland remaining is aqueous sulfuric acid which can be concentrated, if desired, by addition of stronger sulfuric acid, oleum or sulfur trioxide, and may then be recycled to the sulfuric acid feed stream to the anode compartment of the present electrolytic cell. Alternatively, it may be sent to that compartment directly.
  • the chlorine and chlorine dioxide produced in buffer compartment B are recovered as a gaseous mixture. If desired, these products can be separated by contacting the mixture with water to preferentially dissolve the chlorine dioxide.
  • this separation can be effected by contacting the chlorine dioxide-chlorine mixture with a countercurrent stream of water in a conventional absorption tower of the type utilized for separation of chlorine dioxide and chlorine in the previously discussed Day-Kesting process.
  • the chlorine dioxide and chlorine may remain together and be employed in such mixture.
  • the separate or mixed products are useful as bleaching agents, especially for woodpulps.
  • the aqueous alkali metal hydroxide solution recovered from the cathode compartment generally contains about 60 to 250 g./l., usually about to g./l. of alkali metal hydroxide and is free or substantially free of alkali metal chloride, i.e., the product solution generally contains less than about 1 percent alkali metal chloride and under most preferred operating conditions, less than about 0.1 percent.
  • the aqueous caustic product is often suitable, without further purification, for many applications wherein substantially salt-free aqueous alkali metal hydroxides or caustic is desirable or necessary, for example, in pulping wood chips, neutralizing acids, peroxide bleaching, making caustic sulfites and regenerating ion-exchange resins.
  • the present electrolytic cells operate at a voltage of about 2.3 to 5 volts, preferably about 2.5 to 4 volts, and most preferably, about 3 volts.
  • the current density in the cell is about 0.5 to 4, preferably about 1 to 3, more preferably about 3 amperes per square inch of electrode surface.
  • the current efficiency of the present cell is generally at least about 70 percent, and, under preferred operating conditions, is about 75 to 80 percent or greater.
  • the caustic efficiency of the electrolytic cell is generally greater than about 75 percent and, under preferred operating conditions may be 85 to 90 percent or greater.
  • the membranes utilized in the invention to divide the electrolytic cell into compartments and to provide selective ion diffusion are preferably mounted in the cell on networks or screens of supporting material such as polytetrafluoroethylene, perfluorinated ethylenepropylene copolymer, polypropylene, asbestos, titanium, tantalum, niobium or noble metals.
  • polytetrafluoroethylene screening is used.
  • the cation-active and anion-active permselective membranes used are of known classes of proprietary organic polymers, initially often being thermoplastics, which are substituted with a multiplicity of ionogenic substituents and which, in thin film form, are permeable to a certain type of ion. Certain ions, apparently by means of ion exchange with the ionogenic substituents on the polymer film, are able to pass through the polymer membrane, while other ions, of opposite sign, are not able to do so.
  • Cation-active permselective membrane materials which selectively permit passage or diffusion of cations generally contain a multiplicity of sulfonate or sulfonic acid substituents or, in some instances, carboxylate or phosphonate substituents.
  • Cation-active membranes can be prepared by introducing the cation-exchanging substituent, e.g., sulfonate, into a thin film of polymer, e.g., phenol formaldehyde polymer, by chemical reaction, e.g., sulfonation.
  • a homoor copolymer containing the cation-exchanging group(s) can be prepared by polymerizing a monomer substituted with the group(s).
  • phenol sulfonic acid can be substituted for some or all of the phenol normally used as a reactant in preparing a phenol formaldehyde polymer to obtain polysulfonated phenol formaldehyde polymer.
  • acrylic, methacrylic or maleic acid or its anhydride can be polymerized or copolymerized, e.g., with divinyl benzene, to obtain a cation-active membrane material in which the cation exchanging substituents on the polymer base are carboxylate groups.
  • anion-active permselective membranes permit selective passage or diffusion of anions and are impermeable or substantially impermeable to cations.
  • the anion exchanging substituents on the polymer base are generally quaternary ammonium substituents wherein the substituent groups on the nitrogen atoms can be lower alkyl groups, i.e., alkyl groups of l to 6 carbon atoms, such as methyl, ethyl, t-butyl and isopropyl; aralkyl groups, such as benzyl; aryl groups such as phenyl or tolyl; or heterocyclics, such as hydrocarbyl-nitrogen ring-containing compounds, e.g., those containing pyridine groups.
  • Anion-active membrane materials can be made by conventional aminations of thin films of polymer base, e.g., phenol-formaldehyde polymer, polyethylene, polyvinyl chloride and the like, followed by quaternizing of the amino substituents by conventional reaction with an alkylating agent, e.g., a lower alkyl halide, such as methyl iodide or dilower alkyl sulfate such as dimethyl sulfate.
  • an alkylating agent e.g., a lower alkyl halide, such as methyl iodide or dilower alkyl sulfate such as dimethyl sulfate.
  • thin films of polymer bases such as polystyrene, polyethylene and styrene-divinyl benzene copolymers can be haloalkylated, for example, by conventional chloromethylation, to introduce the group -CH Cl, and thereafter may be reacted with a tertiary amine, such as trimethyl amine, to produce the quaternary ammonium substituted anion-active membrane.
  • polymer bases which contain replaceable halogen substituents such as polyvinyl chloride, chlorinated polyethylene, and chlorinated rubber, can be condensed with polyalkylene polyamines, such as tetraethylene pentamine, to produce anion-active polymeric membranes.
  • the cation-active and anion-active polymeric membranes used for selective diffusion of ions are further classified as homogeneous, i.e., polymers visually appearing to be of only one phase, or as heterogeneous, i.e., polymers visually appearing to include more than one phase because of the presence of a matrix material in which the ion exchange polymer is embedded in powdered form.
  • anion-active permselective membranes In addition to the examples of anion-active permselective membranes listed above, the following proprietary compositions are anion-active permselective membranes, and may also be considered as representative of preferred membranes of such type: AMFion 310 series anion type quaternary ammonium substituted flurocarbon polymer, manufactured by American Machine and Foundry Co.; and lonac types MA 3148, MA 3236 and MA 3475-quaternary ammonium substituted polymers derived from heterogeneous polyvinyl chloride, manufactured by the Ritter-Pfaudler Corp., Permutit Division.
  • compositions are representative examples of cation-active permselective membranes which may be used in practicing the present invention: lonac MC 3142, MC 3235, and MC 3470 XL types polysulfonate-substituted heterogeneous polyvinyl chloride, manufactured by the Ritter-Pfaudler Corp., Permutit Division; Nafion XR type hydrolyzed copolymer of perfluorinated olefin and a fluorosulfonated perfluorovinyl ether, manufactured by E. 1.
  • Preferred cation-active permselective membranes of the invention are the hydrolyzed copolymer of perfluoroolefins and fluorosulfonated perfluorovinyl ether, the -SO NHNa modifications thereof and the sul fostyrenated perfluoroethylene-propylene copolymers.
  • the sulfostyrenated perfluoroethylene-propylene polymers useful as cation-active membranes in a preferred embodiment of the invention are generally those which have two-thirds to eleven-sixteenths of the phenyl groups therein monosulfonated and which are about 16 to 18 percent styrenated.
  • FEP perfluoroethylene-propylene copolymer
  • a standard perfluoroethylene-propylene copolymer (hereinafter referred to as FEP), such as is manufactured by E].
  • DuPont de Nemours & Company, Inc. is styrenated and the styre nated polymer is then sulfonated.
  • a solution of styrene in methylene chloride or benzene at a suitable concentration in the range of about 10 to 20 percent is prepared and a sheet of PEP polymer having a thickness of about 0.02 to 0.5 mm., preferably 0.05 to 0.15 mm., is dipped into the solution.
  • the rate of application may be in the range of about 8,000 rads/hr. and a total radiation application is about 0.9 megarad.
  • the phenyl rings of the styrene portion of the polymer are monosulfonated, preferably in the para position, by treatment with chlorosulfonic acid, fuming sulfuric acid or S
  • chlorosulfonic acid in chloroform is utilized and the sulfonation is completed in about one-half hour.
  • Examples of useful membranes made by the described process are the RA] Research Corporation products previously mentioned, l8STl2S and 16 ST13S, the former being 18 percent styrenated and having two-thirds of the phenyl groups monosulfonated and the latter being 16 percent styrenated and having thirteen-sixteenths of the phenyl groups monosulfonated.
  • l8STl2S and 16 ST13S the former being 18 percent styrenated and having two-thirds of the phenyl groups monosulfonated and the latter being 16 percent styrenated and having thirteen-sixteenths of the phenyl groups monosulfonated.
  • 18 percent styrenation a solution of 17 /2 percent of styrene in methylene chloride is utilized and to obtain 16 percent styrenation a solution of 16 percent of styrene in methylene chloride is employed.
  • the especially preferred cation-active permselective membranes of the invention are of a hydrolyzed copolymer of perfluorinated hydrocarbon, e.g., an olefin, and a fluorosulfonated perfluorovinyl ether.
  • the perfluorinated olefin is preferably tetrafluoroethylene, although other perfluorinated hydrocarbons of 2 to carbon atoms may also be utilized, of which the monoolefinic hydrocarbons are preferred, especially those of 2 to 4 carbon atoms and most especially those of 2 to 3 carbon atoms, e.g., tetrafluoroethylene, hexafluoropropylene.
  • PSEPVE perfluoro-[ 2-( 2-fluorosulfonylethoxy )-propyl vinyl ether
  • the copolymer may be made by reacting PSEPVE or equivalent with tetrafluoroethylene or equivalent in desired proportions in water at elevated temperature and pressure for over an hour, after which time the mix is cooled. It separates into a lower perfluoroether layer and an upper layer of aqueous medium with dispersed desired polymer.
  • the molecular weight is indeterminate but the equivalent weight is about 900 to 1,600 preferably 1,100 to 1,400, e.g., 1,250, and the percentage of PSEPVE or corresponding compound is about 10 to percent, preferably 15 to 20 percent and most preferably about 17 percent.
  • the unhydrolyzed copolymer may be compression molded at high tem-' perature and pressure to produce sheets or membranes, which may vary in thickness from 0.02 to 0.5 mm. These are then further treated to hydrolyze pendant -SO F groups to -SO -,H groups, as by treating with 10 percent sulfuric acid or by the methods of the patents previously mentioned. The presence of the -SO H groups may be verified by titration, as described in the Canadian patent. Additional details of various processing steps are described in Canadian Pat. No. 752,427 and U.S. Pat. No. 3,041,317, also hereby incorporated by reference.
  • the copolymer membrane is preferably joined to the backing tetrafluoroethylene or other suitable filaments prior to hydrolysis, when it is still thermoplastic, and the film of copolymer covers each filament, penetrating into the spaces between them and even around behind them, thinning the films slightly in the process, where they cover the filaments.
  • the aminated and hydrolyzed improvements or modifications of the polytetrafluoroethylene PSEPVE copolymers are made, as previously mentioned, by treatment with ammonia of one side of the copolymer, before hydrolysis thereof, and then hydrolyzing with caustic or other suitable alkali. Acid forms may also be utilized.
  • the final hydrolysis may be conducted after the membrane is mounted on its supporting network or screen.
  • the membranes so made are fluorinated polymers having pendant side chains containing sulfonyl groups which are attached to carbon atoms bearing at least one fluorine atom, with sulfonyl groups on one surface being in -(SO NH),,M form, where M is H, N11 alkali metal or alkaline earth metal and n is the 'valence of M, and the sulfonyls of the polymer on the other membrane surface being in -(SO ),Y form or -SO F, wherein Y is a cation and p is the valence of the cation, with the requirement that when Y is H,M is also H.
  • the sulfonamide side faces the cathode.
  • the membranes of hydrolyzed copolymer of perfluorinated olefin and fiuorosulfonated perfluorovinyl ether and the one-side hydrolyzed aminated modifications thereof described are far superior in the present processes to various other cation-active membrane materials.
  • the RA] type membranes are also generally superior to those previously known.
  • the preferred membranes last for much longer time periods in the medium of the cell electrolytes and do not become brittle when subjected to long term contact withchlorine, chlorine dioxide and persulfuric acid. Considering the savings in time and fabrication costs, the present membranes are more economical.
  • the voltage drops through the membranes are acceptable and do not become inordinately high, as they do with many other cation-active membrane materials, when the caustic concentration in the cathode compartment increases to above about 200 g./l. of caustic.
  • the selectivity of the membrane and its compatibility with the electrolyte do not decrease detrimentally as the hydroxyl concentration in the catholyte liquor increases, as has been noted with other cation-active membrane materials.
  • caustic efficiency of the electrolysis does not diminish I as significantly as it does with other membranes when the hydroxyl ion concentration or the alkalinity in the catholyte increases.
  • these differences in the present process make it practicable, whereas previously described processes have not attained commercial acceptability.
  • the more preferred copolymers are those having equivalent weights of 900 to 1,600, with 1,100 to 1,400 being most preferred, some useful resinous membranes employable in present methods may be of equivalent weights from 500 to 4,000.
  • the medium equivalent weight polymers are preferred because they are of satisfactory strength and stability, enable better selective ion exchange to take place and are of lower internal resistances, all of which are important to the present electrochemical cell's improved operation.
  • the improved versions of the TFE PSEPVE copolymers made by chemical treatment of surfaces thereof to modify the -SO l-l group thereon, may have the modification only on the surface or extending up to as much as halfway through the membrane.
  • the depth of treatment will usually be from 0.001 to 0.2 mm., e.g., 0.01 mm.
  • Caustic and other efficiencies of the invented processes, using such modified versions of the present improved membranes can increase about 3 to 20 percent, often about 10 to 20 percent, over the unmodified membranes.
  • the membranes M and M may, if desired, be composed of different cation-active permselective membrane materials but preferably both are of the same polymer.
  • the walls of membranes used in-the present process will normally be from 0.02 to 0.5 mm. thick, preferably 0.1 to 0.4 mm. thick.
  • the networks, screens or cloths have an area percentage of openings therein from about 8 to 80 percent, preferably about 10 to percent and most preferably about 20 to 70 percent.
  • the crosssections of the filaments will be circular but other shapes, such as ellipses,, squares and rectangles, are also useful.
  • the supporting network is preferably a screen or cloth and although it may be cemented to the membrane it is preferred that it be fused to it by high temperature, high pressure compression before hydrolysis of the copolymer. Then, the membrane-network composite can be clamped or otherwise fastened in place in a holder or support.
  • the electrodes of the cell and the conductive means connected thereto can be made of any electrically conductive material which will resist the attack of the various cell contents.
  • the cathodes are made of graphite, iron, lead dioxide, iron in graphite, lead dioxide on graphite, steel or noble metal, such as platinum, iridium, ruthenium or rhodium.
  • noble metals may be deposited as surfaces on conductive substrates, e.g., copper, silver, aluminum, steel, iron.
  • the cell cathode is of mild steel, althoughgraphite, especially high density graphite, i.e., graphite having a density of about 1.68 to 1.78 grams per milliliter may also be used, particularly in a bipolar configuration.
  • the conductive means attached to the cathode may be aluminum, copper, silver, steel or iron,
  • the anode shouldv be resistant to attack by persulfuric acid and accordingly should often be of persulfuric acidinert noble metal.
  • the anode preferably is platinum or platinumclad tantalum, with platinum being much preferred.
  • the conductive means attached to the anode, is also desirably protected against the persulfuric acid in the cathode compartment and preferably is tantalum encased in platinum.
  • the material of construction of the cell body is conventional, including steel, concrete, stressed concrete or other suitably strong material, lined with mastics, rubbers, e.g., neoprene, polyvinylidene chloride, FEP, chlorendic acid based polyester, polypropylene, polyvinyl chloride, polytetrafluoroethylene, or other suitable plastics, usually being in tank or box form.
  • Substantially self-supporting structures such as rigid polyvinyl chloride, polyvinylidene chloride, polypropylene or phenol formaldehyde resins may be employed, preferably reinforced with molded-in fibers, cloths or webs, such as asbestos fibers.
  • compartments of the present cell will usually be separated from each other by flat membranes and will usually be of substantially rectilinear or parallelepipedal construction, various other shapes, including curves, e.g., cylinders, spheres, ellipsoids; and irregular surfaces, e. g., sawtoothed or plurally pointed walls, may also be utilized.
  • curves e.g., cylinders, spheres, ellipsoids
  • irregular surfaces e. g., sawtoothed or plurally pointed walls
  • the volumes of the buffer compartments B and B will be about the same and the combined volume of both buffer compartments will normally be from 1 to 100 percent that of the sum of the volumes of the anode and cathode compartments, preferably from 5 to 70 percent, and the anode and cathode compartment volumes will be approximately the same.
  • the present process provides efficiently, without excessive costly reaction equipment being needed, important woodpulp bleaching reagents, hydrogen peroxide, chlorine dioxide and chlorine together with aqueous caustic which is useful in pulping wood chips. Even the hydrogen produced can be used as a fuel to heat materials for bleaching or pulping. Since the present process requires at most only two or three reaction vessels, it can be readily set up at a single location, which advantageously should be near pulp-manufacturing and pulpbleaching facilities, so as to take advantage of its efficient production of the described pulping chemicals. However, it is also useful for off-site production, too.
  • EXAMPLE 1 A four-compartment electrolytic cell, as illustrated in the FIG., is utilized to produce chlorine, chlorine dioxide, aqueous, substantially salt-free sodium hydroxide, hydrogen and persulfuric acid, which is subsequently hydrolyzed to hydrogen peroxide.
  • the anode is of platinum mesh which is communicated with a positive direct current electrical source through a platinum-clad tantalum conductor rod.
  • the cathode is of mild steel, and is communicated with a negative direct current sink through a copper conductor rod.
  • the anode and cathode are each about two inches wide and about thirty inches high.
  • the cell walls are of asbestos-filled polypropylene.
  • the two cation-active permselective membranes M and M are Nafion membranes manufactured by E. I. duPont de Nemours and Company, Inc. and sold as their XR-type membranes.
  • the membranes are 7 mils thick (about 0.2 rnm.)and are joined to a backing or supporting network of polytetrafluoroethylene (Teflon) filaments of a diameter of about 0.1 mm., woven into cloth which has an area percentage of openings therein of about 22 percent.
  • Teflon polytetrafluoroethylene
  • the membranes are initially flat and are fused onto the Teflon cloth by high temperature, high compression processing, with some of the membrane portions actually flowing around the filaments during the fusion process to lock onto the cloth without, thickening the membrane between the cloth filaments.
  • the anion-active permselective membrane M is derived from a heterogeneous polyvinyl chloride polymer containing a multiplicity of quaternary ammonium substituents.
  • the anion-active membrane is lonac type MA-3475R membrane (manufactured by Ritter- 12. Pfaudler Corporation, Permutit Division), having a thickness of about 14 mils (0.4 mm. which is mounted on a Teflon cloth similar to that employed as a supporting network for the cation-active permselective membranes.
  • the cell electrodes are in contact with the cationactive permselective membranes, with the flatter side of the membranes facing and contacting the electrodes. In some experiments spacings of about 0.01 to 5 mm. between the electrodes and the membranes are utilized and satisfactory results are obtained but the present arrangement, with no spacings, is preferred.
  • the interelectrode distance and the total width of the two buffer compartments, B and B are about 6 mm. and the volume ratio of anode compartment:buffer compartment B zbuffer compartment B cathode compartment is about lO:0.5:0.5:10.
  • the cell is filled with water to about 99 percent of usual capacity, a small open volume, about 5 percent, being left at the top of the cell to facilitate collection of gaseous products from buffer compartment B and the cathode compartment.
  • sulfuric acid is introduced into the anode compartment
  • sodium chloride is charged to buffer compartments B and B
  • sodium hydroxide is introduced into the cathode compartment, to provide about a 1 percent concentration of these electrolytes in the indicated compartments and thereby to provide conduction of electric current through the cell.
  • the cell is externally cooled by circulating water to maintain the cell contents at a temperature of about 30 to 35C.
  • Electrolysis is initiated by passage of direct current through the cell, concentrated aqueous sulfuric acid 1 (containing about 93 percent sulfuric acid) is continuously fed to the anode compartment, an aqueous solution containing about 3 equivalents per liter, i.e., 3 N, of sodium chlorate and about 3 equivalents per liter of sodium chloride is fed continuously to buffer compartment B and water is continuously added to the cathode compartment.
  • the rates of addition of sulfuric acid, chlorate and chloride are adjusted so that the mo] ratio of acid, chlorate, and chloride feed rates is about 2: l 1.
  • Water is charged continuously to the cathode compartment at a rate sufficient to maintain the liquid level in the cell substantially constant.
  • the voltage drop in the cell is about 3 volts and the current density is about 2 amperes per square inch of electrode surface.
  • a sulfuric acid solution of persulfuric acid is continuously withdrawn as product from the anode compartment.
  • This solution is subjected to distillation with steam at 100C. in stoichiometric excess, in a conventional glass steam distillation apparatus, including a still pot equipped with an inlet tube for introducing steam below the surface of liquid in the pot, agitation means, a Water-cooled condenser and a distillate receiver.
  • the steam distillate recovered from the steam distillation is aqueous hydrogen peroxide containing about 4 percent of the peroxide.
  • the distill-and recovered from the steam distillation still pot is about 50 percent aqueous sulfuric acid which is adjusted to the concentration of the sulfuric acid feed stream for the anode compartment by addition of oleum and then is combined with the sulfuric acid feed stream for recycling to the electrolytic cell.
  • a gaseous mixture of chlorine dioxide and chlorine containing about 0.63 parts of chlorine dioxide per part of chlorine is continuously withdrawn as product from buffer compartment B.
  • the mixture is introduced into the base of a conventional chlorine dioxide absorption tower or column of the type illustrated in FIG. 4 of the Canadian Journal of Chemical Engineering, Vol. 36 (1958), page 3, and is contacted with a downwardly flowing counter-current stream of water at ambient temperature to remove chlorine dioxide as about a 3 percent aqueous solution which is recovered from the base of the tower, the purified chlorine gas being recovered from the top of the tower.
  • the aqueous chlorine dioxide product solution is cooled enough so as to precipitate chlorine dioxide as a solid hydrate containing about 16 percent chlorine dioxide, which can be recovered by filtration or decantation.
  • Gaseous hydrogen and aqueous sodium hydroxide are continuously withdrawn as products from the cathode compartment during electrolysis.
  • the aqueous caustic product contains about 80 grams per liter of sodium hydroxide and less than about 0.1 percent sodium chloride.
  • the cell operates at a caustic efficiency of about 90 percent and a current efficiency of about 75 percent.
  • the thicknesses of the cation-active permselective membranes can be increased to to 14 mils, at which thicknesses the caustic efficiency increases but the voltage drop also increases. Accordingly, although cation-active membranes of greater thicknesses are operative in the present process, it is preferred to employ the 7 mil membranes. Cationactive membranes which are 4 mils thick are also used and are satisfactory although caustic efficiency is decreased slightly.
  • the cation-active membranes of the present experiment do not show any deterioration in appearance or operating efficiency or adverse selectivity toward ion diffusion, even after operation in electrolytic processes in contact with oxidizing chemicals such as chlorinde and chlorates, for as long as three years. They withstand the present cells harsh environment very well and require fewer replacements than other nonpreferred membranes. More frequent replacements of the anion-active membranes may be needed but the process efficiency is satisfactory because only one-third of the membranes used by this method are anionactive.
  • Example 2 The procedure of Example 1 is repeated substantially as described except that the anion-active permselective membrane employed is an AMFion 310 series anion type membrane (manufactured by American Machine and Foundry Co.) This membrane, which has a thickness of about 6 mils (about 0.17 mm.), is a proprietary fluorocarbon polymer containing a multiplicity of quaternary ammonium substituents as anion-exchanging groups.
  • the cell using this anion-active membrane is operated continuously with substantially no or little membrane deterioration and with excellent operating results, substantially similar to those obtained in Example 1.
  • Example 3 The procedure of Example I is followed and essentially the same results are obtained, utilizing as cationactive membranes RAI Research Corporation membranes identified as 18ST12S and l6St13S, respectively, and DuPont improved membranes made by the method previously described, instead of the hydrolyzed copolymer of tetrafluoroethylene and sulfonated perfluorovinyl ether.
  • the former of the RAI products is a sulfostyrenated FEP in which the FEP is 18 percent styrenated and has two-thirds of the phenyl groups thereof monosulfonated, and the latter is 16 percent styrenated and has thirteen-sixteenths of the phenyl groups monosulfonated.
  • the anion-active membranes are also changed, to Amberlite resins of the same thick ness, also supported on polytetrafluoroethylene and polypropylene screening.
  • the Amberlites utilized are made by Dow Chemical Corp., and are ammonium and quaternary ammonium functionalized styrenes grafted onto polymeric bases, such as those of PEP, TFE, PVE, PE, nylon and polypropylene.
  • anion-active permselective membranes are employed with cation-active membranes other than the RAI products, including the Ionacs and Nations and the electrodes are both platinum, in one series, or platinum-clad tantalum, in another.
  • two or four additional buffer compartments are employed, inserted between B and B and maintained in the same order as B and B
  • the reactions described produce the desired products, with the sodium hydroxide being even lower in chloride content when additional buffering compartments are utilized.
  • the Amberlite resins do not appear to resist deterioration by the electrolyte as well as the Ionac and Nafion (and modified Nafion) resins previously discussed.
  • drogen peroxide, chlorine, hydrogen and substantially alkali metal chloride-free aqueous alkali metal hydroxide from aqueous alkali metal chloride, aqueous alkali metal chlorate, sulfuric acid and water which comprises electrolyzing in a cell having an anode compartment with an anode therein, a cathode compartment with a cathode therein and intermediate buffer compartments, B and B the anode compartment being separated from B by a cation-active permselective membrane, M the cathode compartment being separated from B by a cation-active permselective membrane, M and B and B being separated from each other by an anion-active permselective membrane, M,
  • chloride and chlorate anions selectively pass from B to B through M
  • alkali metal cations selectively pass from B to the cathode compartment through M
  • sulfuric acid is oxidized at the anode to produce persulfuric acid in the anode compartment
  • chloride and chlorate ions react to produce chlorine and chlorine dioxide in B
  • water and alkali metal cation react at thecathode to produce an aqueous substantially alkali metal halidefree alkali metal hydroxide and hydrogen in the cathode compartment
  • alkali 7 metal chloride, the alkali metal chlorate and the alkali metal hydroxide are sodium chloride, sodium chlorate and sodium hydroxide respectively
  • the M and M cation-active membranes are of the same cationexchange material
  • the cell is operated at a temperature below about 60C. and the persulfuric acid solution recovered from the anode compartment is reacted with at least about 2 moles of water per mol of persulfuric acid in the solution.
  • the material of the anion-active membrane is selected from the group consisting of quaternary ammonium groupsubstituted fluorocarbon polymers and quaternary ammonium-substituted polymers derived from heterogeneous polyvinyl chloride
  • the cation-active membranes are selected from the group consisting of hydrolyzed copolymers of perfluorinated olefin and a fluorosulfonated perfluorinated vinyl ether, fluorinated polymers having pendant side chains containing sulfonyl groups which are attached to carbon atoms bearing at least one fluorine atom, with sulfonyl groups on one surface being in -(SO NH),.M form where M is H,NH alkali metal or alkaline earth metal and n is the valence of M, and the sulfonyls of the polymer on the other membrane surface being in -(SO ),,Y form wherein Y is a
  • anode is of a persulfuric acid-inert noble metal
  • the cathode is a material selected from the group consisting of platinum, iridium, ruthenium, rhodium, graphite, iron and steel
  • the hydrolyzed copolymer is derived from tetrafluoroethylene and fluorosulfonated perfluorovinyl ether of the formula and an equivalent weight of about 900 to 1,600
  • M and Y are both sodium and n and p are both 1
  • the sulfostyrenated perfluorinated ethylene propylene copolymer is about 16 to 18 percent styrenated and has from about two-thirds to thirteensixteenths of the
  • material(s) selected from the group consisting of polytetrafluoroethylene, asbestos, perfluorinated ethylene-propylene copolymer, polypropylene, titanium, tantalum, niobium and noble metals, which have area percentage(s) of openings there
  • a method according to claim 5 wherein the cell operates at a voltage of about 2.3 to 5 volts and a current density of about 0.5 to 4 amperes per square inch of electrode surface, the anode is of platinum or platinum on titanium, the cathode is of mild steel and the substantially sodium chloride-free hydroxide solution contains about 60 to 250 grams per liter of sodium hydroxide.
  • the cationactive' membranes are of the hydrolyzed copolymer having an equivalent weight of about 1,250, the cell operates at about 3 volts and a current density of about 2 amperes per square inch of electrode surface, the anode is of platinum, the concentrations of sodium chlorate and sodium chloride in the feed solution to B are each 3 N, the hydroxide solution recovered from .the cathode compartment contains about grams per liter of sodium hydroxide, and the aqueous sulfuric acid distilland is recycled to the sulfuric acid feed to the anode compartment.
  • anionactive membrane is a quaternary ammonium substituted fluorocarbon polymer.
  • anion-active membrane is a quaternary ammonium substituted polymer derived from a heterogeneous polyvinyl chloride.
  • a method of manufacturing chlorine dioxide, hydrogen peroxide, chlorine, substantially alkali metal chloride-free aqueous alkali metal hydroxide and hydrogen from alkali metal chloride, alkali metal chlorate, sulfuric acid and water- which comprises electrolyzing with a direct current, in a cell having an anode in an anode compartment, a cathode in a cathode compartment and a plurality of intermediate buffer compartments, with the anode compartment being separated from a buffer compartment by a cation-active permselective membrane, the cathode compartment being separated from a buffer compartment by a cation-active permselective membrane and at least one buffer compartment being separated from another by an anion-active permselective membrane, electrolytes resulting from feeds of sulfuric acid to the anode compartment, alkali metal chloride and alkali metal chlorate to a buffer compartment nearer to the cathode compartment than another buffer compartment, and water to the cathode compartment, so that with

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US429998A US3884777A (en) 1974-01-02 1974-01-02 Electrolytic process for manufacturing chlorine dioxide, hydrogen peroxide, chlorine, alkali metal hydroxide and hydrogen
AU75815/74A AU7581574A (en) 1974-01-02 1974-11-27 Electrolytic process for manufacturing chlorine dioxide
BR10588/74A BR7410588D0 (pt) 1974-01-02 1974-12-18 Processo e celula eletrolitica para a producao de dioxido de cloro peroxido de hidrogenio cloro hidrogenio e hidroxido de metal alcalino aquoso substancialemnte isento de cloreto de metal alcalino
CA216,840A CA1043736A (en) 1974-01-02 1974-12-20 Electrolytic process for manufacturing chlorine dioxide, hydrogen peroxide, chlorine, alkali metal hydroxide and hydrogen
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US4000057A (en) * 1974-11-21 1976-12-28 Hooker Chemicals & Plastics Corporation Electrolytic cell membrane conditioning
FR2318665A1 (fr) * 1975-07-25 1977-02-18 Asahi Glass Co Ltd Electrodialyse d'une solution aqueuse de base
US4067787A (en) * 1974-11-13 1978-01-10 Kernforschungsanlage Julich Gesellschaft Mit Beschrankter Haftung Method of making hydrogen peroxide
US4113585A (en) * 1975-10-20 1978-09-12 E. I. Du Pont De Nemours And Company Method and apparatus for electrolysis of alkali or alkaline earth metal halide
US4115217A (en) * 1976-05-11 1978-09-19 Kemanord Ab Process for electrolytic preparation of chlorites
US4246091A (en) * 1977-03-04 1981-01-20 Kureha Kagaku Kogyo Kabushiki Kaisha Process for the electrolytic treatment of alkali halide
US4253900A (en) * 1977-02-28 1981-03-03 Allied Chemical Corporation Method of making novel two component bipolar ion exchange membranes
US4310396A (en) * 1978-12-01 1982-01-12 Societe D'etudes Et De Recherches En Sources D'energie Nouvelles (Sersen) Method for desalination of water, in particular sea water
US4350575A (en) * 1977-12-06 1982-09-21 Battelle Memorial Institute Method for preparing an aqueous treatment solution containing at least hydrogen peroxide ions and hydroxyl ions in predetermined concentrations
US4357218A (en) * 1974-03-07 1982-11-02 Asahi Kasei Kogyo Kabushiki Kaisha Cation exchange membrane and use thereof in the electrolysis of sodium chloride
US4357217A (en) * 1981-10-02 1982-11-02 Occidental Research Corporation Three compartment electrolytic cell method for producing hydrogen peroxide
US4362707A (en) * 1981-04-23 1982-12-07 Diamond Shamrock Corporation Preparation of chlorine dioxide with platinum group metal oxide catalysts
US4381290A (en) * 1981-04-23 1983-04-26 Diamond Shamrock Corporation Method and catalyst for making chlorine dioxide
US4426263A (en) 1981-04-23 1984-01-17 Diamond Shamrock Corporation Method and electrocatalyst for making chlorine dioxide
US4501824A (en) * 1982-02-01 1985-02-26 Eltech Systems Corporation Catalyst for making chlorine dioxide
US4731169A (en) * 1986-10-29 1988-03-15 Tenneco Canada Inc. Selective removal of chlorine from solutions of chlorine dioxide and chlorine
US4780796A (en) * 1987-01-13 1988-10-25 The Japan Carlit Co., Ltd. Solid electrolytic capacitor
EP0365113A1 (en) * 1988-10-20 1990-04-25 Sterling Canada, Inc. Production of chloric acid
WO1990010733A1 (en) * 1989-03-15 1990-09-20 Pulp And Paper Research Institute Of Canada Process for generating chloric acid and chlorine dioxide
US5074975A (en) * 1990-08-08 1991-12-24 The University Of British Columbia Electrochemical cogeneration of alkali metal halate and alkaline peroxide solutions
US5256261A (en) * 1992-08-21 1993-10-26 Sterling Canada, Inc. Membrane cell operation
US5407547A (en) * 1993-10-06 1995-04-18 Eka Nobel Ab Process for production of acidified process streams
FR2731021A1 (fr) * 1995-02-28 1996-08-30 Chemoxal Sa Procede et installation de fabrication de pate a papier utilisant les effluents de traitement basiques d'une installation de production de peroxyde d'hydrogene
US5851374A (en) * 1996-01-11 1998-12-22 Sterling Canada, Inc. Process for production of chlorine dioxide
WO2001038607A1 (en) * 1999-11-26 2001-05-31 Akzo Nobel N.V. Process for production of an alkaline hydrogen peroxide solution and chlorine dioxine
US6387238B1 (en) 1999-08-05 2002-05-14 Steris Inc. Electrolytic synthesis of peracetic acid
US20030082095A1 (en) * 2001-10-22 2003-05-01 Halox Technologies, Inc. Electrolytic process and apparatus
US6666030B2 (en) * 2001-05-30 2003-12-23 Permelec Electrode Ltd. Ice composition containing hydrogen peroxide and method of storing perishable food
US20040071627A1 (en) * 2002-09-30 2004-04-15 Halox Technologies, Inc. System and process for producing halogen oxides
US20050034997A1 (en) * 2003-08-12 2005-02-17 Halox Technologies, Inc. Electrolytic process for generating chlorine dioxide
US20050163700A1 (en) * 2002-09-30 2005-07-28 Dimascio Felice System and process for producing halogen oxides
US20060113196A1 (en) * 2004-07-29 2006-06-01 Chenniah Nanjundiah High-capacity chlorine dioxide generator
US20070012578A1 (en) * 2005-06-30 2007-01-18 Akzo Nobel N.V. Chemical process
US20070012579A1 (en) * 2005-06-30 2007-01-18 Akzo Nobel N.V. Chemical process
WO2007064850A2 (en) * 2005-11-30 2007-06-07 Pureline Treatment Systems, Llc Chlorine dioxide generator
US7399344B1 (en) * 2005-01-28 2008-07-15 Uop Llc Hydrogen peroxide recovery with hydrophobic membrane
FR3066199A1 (fr) * 2017-05-10 2018-11-16 Claude Agneletti Dispositif de valorisation du gaz carbonique dans le cadre d'une cogeneration perfectionnee
US20180370795A1 (en) * 2016-06-22 2018-12-27 Earl Lorenzo Hamm Apparatus and method for hydrogen production from an alkali metal and hydrogen dioxide

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JPS5222866A (en) * 1975-08-15 1977-02-21 Victor Co Of Japan Ltd Demodulation system for angle modulated signal wave
CA1287815C (en) * 1987-05-29 1991-08-20 Marek Lipsztajn Electrolytic production of chlorine dioxide
WO1993021106A1 (en) * 1992-04-15 1993-10-28 A. Ahlstrom Corporation Production of bleaching chemicals on site at a pulp mill
CN114314765A (zh) * 2021-12-28 2022-04-12 湖北华德莱节能减排科技有限公司 一种电化学资源化脱硫废水协同产氢的方法、装置及应用

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US3234110A (en) * 1959-02-06 1966-02-08 Amalgamated Curacao Patents Co Electrode and method of making same
US3344053A (en) * 1964-05-04 1967-09-26 Dow Chemical Co Chlorine cell
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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

Cited By (48)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4357218A (en) * 1974-03-07 1982-11-02 Asahi Kasei Kogyo Kabushiki Kaisha Cation exchange membrane and use thereof in the electrolysis of sodium chloride
US4067787A (en) * 1974-11-13 1978-01-10 Kernforschungsanlage Julich Gesellschaft Mit Beschrankter Haftung Method of making hydrogen peroxide
US4000057A (en) * 1974-11-21 1976-12-28 Hooker Chemicals & Plastics Corporation Electrolytic cell membrane conditioning
FR2318665A1 (fr) * 1975-07-25 1977-02-18 Asahi Glass Co Ltd Electrodialyse d'une solution aqueuse de base
US4113585A (en) * 1975-10-20 1978-09-12 E. I. Du Pont De Nemours And Company Method and apparatus for electrolysis of alkali or alkaline earth metal halide
US4115217A (en) * 1976-05-11 1978-09-19 Kemanord Ab Process for electrolytic preparation of chlorites
US4253900A (en) * 1977-02-28 1981-03-03 Allied Chemical Corporation Method of making novel two component bipolar ion exchange membranes
US4246091A (en) * 1977-03-04 1981-01-20 Kureha Kagaku Kogyo Kabushiki Kaisha Process for the electrolytic treatment of alkali halide
US4350575A (en) * 1977-12-06 1982-09-21 Battelle Memorial Institute Method for preparing an aqueous treatment solution containing at least hydrogen peroxide ions and hydroxyl ions in predetermined concentrations
US4310396A (en) * 1978-12-01 1982-01-12 Societe D'etudes Et De Recherches En Sources D'energie Nouvelles (Sersen) Method for desalination of water, in particular sea water
US4381290A (en) * 1981-04-23 1983-04-26 Diamond Shamrock Corporation Method and catalyst for making chlorine dioxide
US4362707A (en) * 1981-04-23 1982-12-07 Diamond Shamrock Corporation Preparation of chlorine dioxide with platinum group metal oxide catalysts
US4426263A (en) 1981-04-23 1984-01-17 Diamond Shamrock Corporation Method and electrocatalyst for making chlorine dioxide
US4357217A (en) * 1981-10-02 1982-11-02 Occidental Research Corporation Three compartment electrolytic cell method for producing hydrogen peroxide
US4501824A (en) * 1982-02-01 1985-02-26 Eltech Systems Corporation Catalyst for making chlorine dioxide
US4731169A (en) * 1986-10-29 1988-03-15 Tenneco Canada Inc. Selective removal of chlorine from solutions of chlorine dioxide and chlorine
US4780796A (en) * 1987-01-13 1988-10-25 The Japan Carlit Co., Ltd. Solid electrolytic capacitor
EP0365113A1 (en) * 1988-10-20 1990-04-25 Sterling Canada, Inc. Production of chloric acid
WO1990010733A1 (en) * 1989-03-15 1990-09-20 Pulp And Paper Research Institute Of Canada Process for generating chloric acid and chlorine dioxide
US5074975A (en) * 1990-08-08 1991-12-24 The University Of British Columbia Electrochemical cogeneration of alkali metal halate and alkaline peroxide solutions
US5256261A (en) * 1992-08-21 1993-10-26 Sterling Canada, Inc. Membrane cell operation
US5407547A (en) * 1993-10-06 1995-04-18 Eka Nobel Ab Process for production of acidified process streams
FR2731021A1 (fr) * 1995-02-28 1996-08-30 Chemoxal Sa Procede et installation de fabrication de pate a papier utilisant les effluents de traitement basiques d'une installation de production de peroxyde d'hydrogene
WO1996027046A1 (fr) * 1995-02-28 1996-09-06 Chemoxal S.A. Procede et installation de fabrication de pate a papier utilisant les effluents de traitement basiques d'une installation de production de peroxyde d'hydrogene
US5851374A (en) * 1996-01-11 1998-12-22 Sterling Canada, Inc. Process for production of chlorine dioxide
US6387238B1 (en) 1999-08-05 2002-05-14 Steris Inc. Electrolytic synthesis of peracetic acid
WO2001038607A1 (en) * 1999-11-26 2001-05-31 Akzo Nobel N.V. Process for production of an alkaline hydrogen peroxide solution and chlorine dioxine
US6666030B2 (en) * 2001-05-30 2003-12-23 Permelec Electrode Ltd. Ice composition containing hydrogen peroxide and method of storing perishable food
US20030082095A1 (en) * 2001-10-22 2003-05-01 Halox Technologies, Inc. Electrolytic process and apparatus
US6869517B2 (en) 2001-10-22 2005-03-22 Halox Technologies, Inc. Electrolytic process and apparatus
US7241435B2 (en) 2002-09-30 2007-07-10 Halox Technologies, Inc. System and process for producing halogen oxides
US20040071627A1 (en) * 2002-09-30 2004-04-15 Halox Technologies, Inc. System and process for producing halogen oxides
US20050095192A1 (en) * 2002-09-30 2005-05-05 Dimascio Felice System and process for producing halogen oxides
US6913741B2 (en) 2002-09-30 2005-07-05 Halox Technologies, Inc. System and process for producing halogen oxides
US20050163700A1 (en) * 2002-09-30 2005-07-28 Dimascio Felice System and process for producing halogen oxides
US20050034997A1 (en) * 2003-08-12 2005-02-17 Halox Technologies, Inc. Electrolytic process for generating chlorine dioxide
US7179363B2 (en) 2003-08-12 2007-02-20 Halox Technologies, Inc. Electrolytic process for generating chlorine dioxide
US20060113196A1 (en) * 2004-07-29 2006-06-01 Chenniah Nanjundiah High-capacity chlorine dioxide generator
US7914659B2 (en) 2004-07-29 2011-03-29 Pureline Treatment Systems, Llc High-capacity chlorine dioxide generator
US7399344B1 (en) * 2005-01-28 2008-07-15 Uop Llc Hydrogen peroxide recovery with hydrophobic membrane
US20080237057A1 (en) * 2005-01-28 2008-10-02 Lin Li Hydrogen Peroxide Recovery with Hydrophobic Membrane
US20070012578A1 (en) * 2005-06-30 2007-01-18 Akzo Nobel N.V. Chemical process
US20070012579A1 (en) * 2005-06-30 2007-01-18 Akzo Nobel N.V. Chemical process
US8034227B2 (en) 2005-06-30 2011-10-11 Akzo Nobel N.V. Chemical process
WO2007064850A2 (en) * 2005-11-30 2007-06-07 Pureline Treatment Systems, Llc Chlorine dioxide generator
WO2007064850A3 (en) * 2005-11-30 2008-03-06 Pureline Treat Systems Llc Chlorine dioxide generator
US20180370795A1 (en) * 2016-06-22 2018-12-27 Earl Lorenzo Hamm Apparatus and method for hydrogen production from an alkali metal and hydrogen dioxide
FR3066199A1 (fr) * 2017-05-10 2018-11-16 Claude Agneletti Dispositif de valorisation du gaz carbonique dans le cadre d'une cogeneration perfectionnee

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FR2256263A1 (US06368395-20020409-C00050.png) 1975-07-25
FR2256263B1 (US06368395-20020409-C00050.png) 1976-12-31
JPS5098499A (US06368395-20020409-C00050.png) 1975-08-05
BR7410588D0 (pt) 1975-09-02
FI376974A (US06368395-20020409-C00050.png) 1975-07-03
SE7416364L (US06368395-20020409-C00050.png) 1975-07-03
AU7581574A (en) 1976-05-27
CA1043736A (en) 1978-12-05
JPS5322960B2 (US06368395-20020409-C00050.png) 1978-07-12
SE409884B (sv) 1979-09-10

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