EP0328818B1 - Production of chlorine dioxide in an electrolytic cell - Google Patents

Production of chlorine dioxide in an electrolytic cell Download PDF

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Publication number
EP0328818B1
EP0328818B1 EP88311380A EP88311380A EP0328818B1 EP 0328818 B1 EP0328818 B1 EP 0328818B1 EP 88311380 A EP88311380 A EP 88311380A EP 88311380 A EP88311380 A EP 88311380A EP 0328818 B1 EP0328818 B1 EP 0328818B1
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EP
European Patent Office
Prior art keywords
cathode compartment
ions
cathode
chlorine
compartment
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP88311380A
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German (de)
English (en)
French (fr)
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EP0328818A3 (en
EP0328818A2 (en
Inventor
Marek Lipsztajn
James Duncan Mcgilvery
Zbigniew Twardowski
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Sterling Canada Inc
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Sterling Canada Inc
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Priority to AT88311380T priority Critical patent/ATE91306T1/de
Publication of EP0328818A2 publication Critical patent/EP0328818A2/en
Publication of EP0328818A3 publication Critical patent/EP0328818A3/en
Application granted granted Critical
Publication of EP0328818B1 publication Critical patent/EP0328818B1/en
Anticipated expiration legal-status Critical
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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
    • C25B1/34—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
    • 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

Definitions

  • the present invention relates to the production of chlorine dioxide in substantially pure form, i.e. substantially free from chlorine.
  • Chlorine dioxide is widely used as a bleaching chemical and is known to be produced by reduction of sodium chlorate in an acid aqueous reaction medium.
  • the reaction whereby chlorine dioxide is formed is represented by the equation: ClO3 ⁇ + Cl ⁇ + 2H+ ⁇ ClO2 ⁇ + 1 ⁇ 2Cl2 + H2O Generally, therefore, chlorine is co-produced with the chlorine dioxide.
  • Processes are known wherein the chlorine so-produced is reduced chemically, for example, using sulphur dioxide or methanol, thereby producing chloride ions for the process in situ .
  • Such processes employ sulphuric acid as the acid source, resulting in sodium sulphate by-product.
  • EP-A-0293151 (equivalent to U.S. Patent No. 4,731,169), wherein chlorate ions are reduced by electrolytically-produced chlorite ions at an acid normality of at least 7 normal sulfuric acid, the chlorite ions being produced by electrochemical reduction of a portion of the chlorine dioxide produced by the process.
  • EP-A-0293151 claims a priority date of 29 May 1987 but was not published until 30 November 1988.
  • an electrolytic process for the production of chlorine dioxide which is carried out in the cathode compartment of a cation-exchange membrane divided cell in which co-produced chlorine is reduced electrolytically in the cathode compartment in which is positioned a high surface area cathode having a three-dimensional electroconductive surface.
  • Chlorate ions usually in the form of an aqueous sodium chlorate solution, are fed to the cathode compartment in which are provided hydrogen ions and chloride ions.
  • the chlorate ions are reduced with the hydrogen ions and chloride ions in the cathode compartment to produce the chlorine dioxide, which is vented from the cathode compartment, while an electric current is applied to reduce the co-produced chlorine to chloride ions.
  • Hydrogen ions are electrolytically formed in the anode compartment and are transferred from the anode compartment to the cathode compartment. In this way, high purity chlorine dioxide is produced electrolytically from chlorate feed.
  • the chlorine dioxide is generated chemically in the cathode compartment according to the equation: NaClO3 + 2H+ + 2Cl ⁇ ⁇ ClO2 + 1 ⁇ 2Cl2 + NaCl + H2O
  • the chlorine co-produced with the chlorine dioxide in the cathode compartment in accordance with this equation is electrolytically reduced to chloride ions, leaving the product chlorine dioxide exiting from the cathode compartment substantially free from the chlorine.
  • Water is fed to the anolyte compartment of the cell, after an initial charge of an oxy-acid.
  • the electrolysis carried out in the cell produces oxygen gas, which is vented from the anode compartment, and hydrogen ions, which migrate across the cation-exchange membrane into the anode compartment to provide hydrogen ions therein for the chemical reaction producing chlorine dioxide therein.
  • oxygen gas which is vented from the anode compartment
  • hydrogen ions which migrate across the cation-exchange membrane into the anode compartment to provide hydrogen ions therein for the chemical reaction producing chlorine dioxide therein.
  • the cathode compartment requires the feed of 1 mole of sodium chlorate, 1 mole of hydrogen ions and 1 mole of chloride ions to maintain the chlorine dioxide production as a continuous process.
  • 1 ⁇ 2 mole of chlorine may be fed to the cathode compartment along with one mole of sodium chlorate.
  • two moles of H+ are transferred from the anode compartment to the cathode compartment to satisfy the hydrogen ion requirement of the process, while the 1 ⁇ 2 mole of chlorine fed to the cathode compartment and the 1 ⁇ 2 mole of chlorine co-produced in the cathode compartment are electrochemically reduced to provide the two moles of chloride ions.
  • FIG. 1 there is shown therein an electrolytic cell 10 for the production of chlorine dioxide in accordance with one embodiment of the invention.
  • Aqueous sodium chlorate solution is fed by line 12 to the cathode compartment 14 of the cell 10, which contains a three-dimensional electrode.
  • An acid, preferably hydrochloric acid, also is fed to the cathode compartment 14 by line 16.
  • the aqueous sodium chlorate solution fed by line 12 has a concentration sufficient to establish, at its flow rate, a relatively high concentration of sodium chlorate in the cathode compartment 14, generally greater than about 5 molar, preferably about 5 to about 6.5 molar.
  • the sodium chlorate feed solution has a concentration in the range of about 3 to about 7 molar.
  • the cell 10 has a cation-exchange membrane 18 separating the cathode compartment 14 from an anode compartment 20.
  • an oxy-acid usually sulfuric acid
  • water is fed by line 22 to the anode compartment 20 and hydrogen ions produced by electrolysis of the anolyte migrate across the cation-exchange membrane 18 to the cathode compartment 14.
  • the anolyte sulfuric acid solution is recirculated by line 23.
  • the hydrogen ion migration across the cation-exchange membrane 18 and the feed of hydrochloric acid by line 16 establish a total acid normality in the cathode compartment 18 of at least about 0.01 normal, preferably at least about 0.05 normal.
  • the oxygen co-produced in the electrolysis step in the anode compartment is vented by line 24 from the anode compartment 20.
  • the sodium chlorate fed by line 12 reacts chemically with the hydrogen ions and chloride ions fed by line 16, the electrolytically-produced hydrogen ions transferred across the cation-exchange membrane and the chloride ions electrolytically produced in the cathode compartment 14 as described below, to form chlorine dioxide and chlorine in accordance with the equation: NaClO3 + 2H+ + 2Cl ⁇ ⁇ ClO2 + 1 ⁇ 2Cl2 + NaCl + H2O
  • One half of the hydrogen ion requirement is provided by the acid fed by line 16 with the remainder of the hydrogen ion requirement is provided by the hydrogen ions transferred from the anode compartment 20.
  • the co-produced chlorine is reduced under the electrochemical conditions which exist in the cathode compartment 14, selectively with respect to the chlorine dioxide present therein.
  • the chloride ions so produced provide half the chloride ions for the chemical reduction of the chlorate, with the remainder of the chloride ions being provided by the hydrochloric acid feed in line 16, or from some other convenient external source of chloride ions, such as sodium chloride.
  • the chloride ions may be produced directly from the co-produced chlorine by electrochemical reduction, in accordance with the equation: 1 ⁇ 2Cl2 + e ⁇ Cl ⁇ or indirectly by reduction chemically with chlorite ion electrolytically produced from chlorine dioxide, in accordance with the equations: In this latter procedure, the chlorite ion formation is controlled so as to avoid further electrolytic reduction of chlorite, which inefficiently produces chlorine.
  • the chlorine concentration in the product off-gas stream in line 26 may be monitored and the current applied to the cell is used to control the chlorine concentration.
  • the feeds of sodium chlorate by line 12 and of chloride ions by line 16 as well as the electrochemically-produced chloride ions establish a chlorate to chloride ion ratio in the cathode compartment 14 generally at least about 1:1, preferably about 2:1 to about 4:1.
  • the electrode potential which is applied to the cathode is more positive than -1 volt as compared with a saturated calomel electrode (SCE) and as determined at the current feeder to the cathode and more negative than the open circuit potential under the prevailing conditions, preferably about -0.2 volt.
  • SCE saturated calomel electrode
  • the electrode potential of the cathode refers to the solution potential measured at the current feeder, in analogous manner to a flat plate electrode.
  • the cathode compartment 14 preferably is maintained at an elevated temperature to assist in the rate of chlorine dioxide formation. Usually, a temperature in excess of about 50°C is employed, preferably about 60° to about 70°C.
  • chlorine can be fed to the cathode compartment 14 in place of the hydrogen ions and chloride ions in line 16, for selective reduction to chloride ions along with the selective reduction of the co-produced chlorine.
  • the anolyte feed is increased so as to provide twice as much hydrogen ion migration across the membrane 18 and hence provide all the hydrogen ion requirement of the cathode compartment 14.
  • the chlorine dioxide produced in the chemical reaction is vented from the cathode compartment 14 as the product gas stream by line 26.
  • This chlorine dioxide stream may be utilized further, as described, for example, with respect to the embodiment of Figure 2 below.
  • the by-product sodium chloride from the chemical production of chlorine dioxide is removed from the cathode compartment as an aqueous solution by line 28.
  • This aqueous sodium chloride solution may be forwarded to a chlorate cell for electrolytic conversion to aqueous sodium chlorate solution for recycle to the cathode compartment 14 to provide at least part of the sodium chlorate in line 12.
  • the cathode employed in the cathode compartment 14 is a high surface area electrode having a three-dimensional electrolyte-contacting surface, which permits a long contact time between the reactants.
  • high surface area in relation to the cathode refers to an electrode of the type wherein the electrolyte is exposed to a large surface area of electrode surface in comparison to the physical dimensions of the electrode.
  • the electrode is formed with interstices through which the electrolyte flows, and so has a three-dimensional surface of contact with the electrolyte.
  • the high surface area cathode may be the so-called "flow through” type, wherein the electrode is formed of electroconductive porous material, for example, layers of electroconductive cloth and the electrolyte flows through the porous structure generally parallel to the current flow while being subjected to electrolysis, and thereby is exposed to the high surface area of the mesh of the electrode.
  • the high surface area cathode also may be the so-called "flow by" type, wherein the electrode comprises a packed bed of individual electroconductive particles and the electrolyte flows through the packed bed generally perpendicular to the current flow while being subjected to electrolysis, and thereby is exposed to the high surface area of the electroconductive particles in the packed bed.
  • the electrode may be constructed of materials having a low overpotential or preferably high overpotential, particularly graphite, for the reaction Cl2 ⁇ Cl ⁇ .
  • the overpotential of an electrode towards the electrochemical reaction Cl2/Cl ⁇ refers to the relationship of the potential applied to the electrode to the equilibrium potential to sustain the electrochemical reaction at a reasonable rate. If the electrode potential is close to the equilibrium potential, then the electrode is considered to have a "low" overpotential while, if a much more negative potential is required to achieve a significant reduction rate, then the electrode is considered to have a "high" overpotential.
  • Such electrodes generally comprise a substrate, which is titanium, zirconium, tantalum or hafnium, having an electroconductive coating thereon, which may be a precious metal, for example, platinum; a precious metal alloy, for example, a platinum-iridium alloy; a metal oxide, for example, ruthenium oxide or titanium dioxide; a palatinate, for example, lithium palatinate or calcium palatinate; or mixtures of two or more of such materials. Any of these materials may be employed to provide the material of construction of a low overpotential cathode.
  • the cell 10 in which the electrolytic production of chlorine dioxide is effected in accordance with the present invention may have any convenient construction.
  • the cell is divided into anolyte and catholyte compartments 20 and 14 by an ion-exchange membrane 18, usually a cation-exchange membrane so as to promote hydrogen ion transfer and to prevent the interaction of gases produced at the anode, usually oxygen, with the chlorine dioxide and the electroreduction at the cathode.
  • the anode of the cell may be constructed of any desired electroconductive material, for example, graphite or metal.
  • Chlorine dioxide formed in the generator 10 is forwarded by line 26 to the cathode compartment 36 of the chlorite-generating cell 32.
  • Sodium chloride is fed by line 38 to an anode compartment 40 of the chlorite-generating cell 32.
  • Anodic electrolysis produces chlorine while sodium ions migrate across a cation-exchange membrane 42 separating the anode compartment 40 from the cathode compartment 36.
  • the chlorine dioxide forwarded by line 26 forms chlorite ions, resulting in a discharge of sodium chlorite solution in line 44 from the cathode compartment 36.
  • Depleted sodium chloride solution exiting the anode compartment 40 is recycled by line 46.
  • the chlorine formed in the anode compartment 40 is passed by line 48 to the cathode compartment 14 of the chlorine dioxide generator 10.
  • all the hydrogen ions and chloride ions for the cathodic production of chlorine dioxide are produced in situ in compartment 14 from the chlorine fed by line 48 and hydrogen ion migration. This result is achieved by increasing the current supplied to the cell from 1 Faraday to 2 Faradays per mole of chlorine dioxide produced.
  • the overall process between the chlorine dioxide generator 10 and the chlorite cell 32 requires no additional input of hydrogen ions and/or chloride ions, since all the hydrogen ions and/or chloride ions required by the chlorine dioxide generator are provided within the system and no chlorine output requires to be handled. Further integration with the chlorate cell produces a system wherein the only inputs are sodium chloride and power and the only outputs are sodium chlorite, hydrogen and oxygen.
  • a modification of the procedure of Figure 2 involves forwarding sodium chloride from the anolyte chamber 40 of the chlorite-generating cell 32 to the chlorate cell 30.
  • any hypochlorous acid in the hydrogen off-gas stream 34 may be condensed and recycled to cathode compartment of the chlorine dioxide generator 10.
  • FIG 3 there is illustrated integration of the chlorine dioxide generator 10 with a caustic-chlorine cell 50.
  • the sodium chloride by-product, along with unreacted sodium chlorate is forwarded by line 28 to the anode compartment 52 of the caustic-chlorine cell 50.
  • An electrolyte is forwarded by line 54 to the cathode compartment 56 of the caustic-chlorine cell 50, separated from the anode compartment 52 by a cation-exchange membrane 58.
  • Chlorine produced in the anode compartment 52 is forwarded as an aqueous solution in the unreacted sodium chlorate, by line 60 to the cathode compartment of the chlorine dioxide generator 10.
  • Sodium hydroxide is recovered from the cathode compartment 50 as product in line 62 and by-product hydrogen gas is vented by line 64.
  • the invention is illustrated by the following Example: An experimental cell was set up as seen in Figure 1.
  • the cell was a conventional MP cell from Electrocell AB which had been modified to accommodate a three-dimensional electrode formed by inserting a graphite felt (Union Carbide Corporation) into the cathode compartment.
  • the cell was divided into anode and cathode compartments by a cation exchange membrane (NAFION 120).
  • NAFION 120 cation exchange membrane
  • the membrane area was 1 sq.dm while the area of the cathode was estimated to be approximately 100 to 1000 times the membrane area.
  • An oxygen-evolving dimensionally-stable electrode was used as the anode.
  • Feed to the cathode compartment was 8.626 moles of sodium chlorate, 2.356 moles of sodium chloride and 1.536 moles of HCl. 6N H2SO4 was used as the anolyte.
  • An electrode potential of about -0.7 volts vs. SCE was applied to the cathode at a current density of 1.97 kA/m2 for a period of 4 hrs at 70°C.
  • the effluent from the cathode chamber contained 7.659 moles NaClO3 and 3.548 moles NaCl.
  • the off-gases were analyzed and contained 0.626 moles of ClO2 and 0.068 moles of Cl2.
  • the chlorine dioxide had a purity of 90.2%, produced at a chemical efficiency of 82.2%.
  • the present invention provides a novel electrolyte process for the production of chlorine dioxide in substantially pure form. Modifications are possible within the scope of this invention.

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  • Chemical & Material Sciences (AREA)
  • Inorganic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Electrolytic Production Of Non-Metals, Compounds, Apparatuses Therefor (AREA)
EP88311380A 1988-02-16 1988-12-01 Production of chlorine dioxide in an electrolytic cell Expired - Lifetime EP0328818B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT88311380T ATE91306T1 (de) 1988-02-16 1988-12-01 Herstellung von chlordioxyd in einer elektrolytischen zelle.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CA558945 1988-02-16
CA000558945A CA1330964C (en) 1988-02-16 1988-02-16 Production of chlorine dioxide in an electrolytic cell

Publications (3)

Publication Number Publication Date
EP0328818A2 EP0328818A2 (en) 1989-08-23
EP0328818A3 EP0328818A3 (en) 1989-12-06
EP0328818B1 true EP0328818B1 (en) 1993-07-07

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Application Number Title Priority Date Filing Date
EP88311380A Expired - Lifetime EP0328818B1 (en) 1988-02-16 1988-12-01 Production of chlorine dioxide in an electrolytic cell

Country Status (17)

Country Link
EP (1) EP0328818B1 (pl)
JP (1) JPH01219185A (pl)
AR (1) AR240340A1 (pl)
AT (1) ATE91306T1 (pl)
AU (1) AU604590B2 (pl)
BR (1) BR8807003A (pl)
CA (1) CA1330964C (pl)
DE (1) DE3882220T2 (pl)
ES (1) ES2041321T3 (pl)
FI (1) FI87936C (pl)
NO (1) NO173513C (pl)
NZ (1) NZ227199A (pl)
PL (1) PL160949B1 (pl)
PT (1) PT89221B (pl)
RU (1) RU1836493C (pl)
YU (1) YU46719B (pl)
ZA (1) ZA889170B (pl)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7153586B2 (en) 2003-08-01 2006-12-26 Vapor Technologies, Inc. Article with scandium compound decorative coating
US8123967B2 (en) 2005-08-01 2012-02-28 Vapor Technologies Inc. Method of producing an article having patterned decorative coating

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA1324976C (en) * 1988-07-26 1993-12-07 Zbigniew Twardowski Combined process for production of chlorine dioxide and sodium hydroxide
DE102007017625A1 (de) * 2007-04-12 2008-10-16 Hosni Dr. Khalaf Verfahren zur Herstellung von Chlordioxid
FR2961756B1 (fr) * 2010-06-29 2014-03-07 Michelin Soc Tech Systeme de production et d'alimentation en hydrogene et en chlorate de sodium, comportant un electrolyseur au chlorure de sodium pour produire le chlorate de sodium
AU2015289095B2 (en) * 2014-07-17 2019-04-04 Industrie De Nora S.P.A. Catalytic or electrocatalytic generation of chlorine dioxide
CN114921799B (zh) * 2022-05-11 2024-09-06 上海交通大学 单原子阴阳极同时合成高纯二氧化氯气体的方法及其装置

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4426263A (en) * 1981-04-23 1984-01-17 Diamond Shamrock Corporation Method and electrocatalyst for making chlorine dioxide
CA1252753A (en) * 1986-10-29 1989-04-18 Sterling Canada, Inc. Selective removal of chlorine from solutions of chlorine dioxide and chlorine
CA1287815C (en) * 1987-05-29 1991-08-20 Marek Lipsztajn Electrolytic production of chlorine dioxide
US4767510A (en) * 1987-06-03 1988-08-30 Tenneco Canada Inc. Electrolytic protection of chlorine dioxide

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7153586B2 (en) 2003-08-01 2006-12-26 Vapor Technologies, Inc. Article with scandium compound decorative coating
US8123967B2 (en) 2005-08-01 2012-02-28 Vapor Technologies Inc. Method of producing an article having patterned decorative coating

Also Published As

Publication number Publication date
JPH021917B2 (pl) 1990-01-16
ATE91306T1 (de) 1993-07-15
ZA889170B (en) 1989-10-25
FI87936B (fi) 1992-11-30
FI890172L (fi) 1989-08-17
JPH01219185A (ja) 1989-09-01
NZ227199A (en) 1990-03-27
NO885436L (no) 1989-08-17
CA1330964C (en) 1994-07-26
PT89221A (pt) 1990-03-08
BR8807003A (pt) 1990-08-07
EP0328818A3 (en) 1989-12-06
DE3882220D1 (de) 1993-08-12
ES2041321T3 (es) 1993-11-16
NO885436D0 (no) 1988-12-07
PL160949B1 (pl) 1993-05-31
AU604590B2 (en) 1990-12-20
FI87936C (fi) 1993-03-10
PT89221B (pt) 1993-09-30
DE3882220T2 (de) 1994-02-17
RU1836493C (ru) 1993-08-23
EP0328818A2 (en) 1989-08-23
FI890172A0 (fi) 1989-01-13
AR240340A1 (es) 1990-03-30
NO173513C (no) 1993-12-22
PL276597A1 (en) 1989-08-21
YU235988A (en) 1990-10-31
YU46719B (sh) 1994-04-05
NO173513B (no) 1993-09-13
AU2697788A (en) 1989-08-17

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