US3884776A - Preparation of hydroquinone - Google Patents

Preparation of hydroquinone Download PDF

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US3884776A
US3884776A US360427A US36042773A US3884776A US 3884776 A US3884776 A US 3884776A US 360427 A US360427 A US 360427A US 36042773 A US36042773 A US 36042773A US 3884776 A US3884776 A US 3884776A
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quinone
benzene
catholyte
anolyte
aqueous
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Frederick Andrew Keidel
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EIDP Inc
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EI Du Pont de Nemours and Co
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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
    • C25B3/00—Electrolytic production of organic compounds
    • C25B3/01—Products
    • C25B3/03—Acyclic or carbocyclic hydrocarbons
    • 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
    • C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
    • C25B11/02—Electrodes; Manufacture thereof not otherwise provided for characterised by shape or form
    • 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
    • C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
    • C25B11/02—Electrodes; Manufacture thereof not otherwise provided for characterised by shape or form
    • C25B11/036—Bipolar electrodes
    • 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
    • C25B3/00—Electrolytic production of organic compounds
    • C25B3/01—Products
    • C25B3/07—Oxygen containing 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
    • C25B9/00—Cells or assemblies of cells; Constructional parts of cells; Assemblies of constructional parts, e.g. electrode-diaphragm assemblies; Process-related cell features
    • C25B9/70—Assemblies comprising two or more cells
    • C25B9/73—Assemblies comprising two or more cells of the filter-press type
    • C25B9/75—Assemblies comprising two or more cells of the filter-press type having bipolar electrodes
    • 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
    • C25B9/00—Cells or assemblies of cells; Constructional parts of cells; Assemblies of constructional parts, e.g. electrode-diaphragm assemblies; Process-related cell features
    • C25B9/70—Assemblies comprising two or more cells
    • C25B9/73—Assemblies comprising two or more cells of the filter-press type
    • C25B9/77—Assemblies comprising two or more cells of the filter-press type having diaphragms

Definitions

  • An economical process for producing hydroquinone in a single electrolytic cell comprises anodizing benzene dispersed in an aqueous anolyte in one half cell to produce a quinone-rich benzene phase while catholyzing quinone-rich benzene dispersed in aqueous catholyte of the other half cell to produce a benzene phase depleted in quinone and an aqueous catholyte containing hydroquinone, transferring quinone-rich benzene phase from the anolyte to the catholyte, transferring the benzene phase depleted in quinone from the catholyte to the anolyte and recovering hydroquinone from the catholyte by crystallization.
  • the dispersions of benzene phases in the anolyte and the catholyte are flowed at high velocity along the anode and the cathode having expanded electrically active surface.
  • Catholysis can be accelerated in the presence of a selected redox couple such as Cr Cr 11 Claims, 7 Drawing Figures PATENTED MAY 2 01975 SHEET 1 BF 3 FATENTEU 3491201975 SHEET 20F 3 FIG. 3
  • An electrolytic process for hydroquinone production which oxidizes benzene to quinone and simultaneously reduces quinone to hydroquinone in the same cell is highly desirable because it is capable of saving electrochemical energy and process investment. It is desirable, however, to avoid expensive organic solvent extraction for hydroquinone isolation and minimize electrolyte discard.
  • this invention is directed to a process for preparing hydroquinone from benzene in a single electrolytic cell having an anode and a cathode separated by an ion-permeable membrane which comprises A. anolyzing a dispersion of benzene phase in aqueous anolyte at the anode electrode, thereby producing benzene enriched with quinone while B. simultaneously catholyzing a dispersion in aqueous catholyte of benzene phase enriched with quinone at the cathode electrode, thereby producing a benzene phase of lowered quinone content and aqueous catholyte phase enriched with hydroquinone.
  • FIG. 1 is a section through the axis of a suitable cell.
  • FIG. 2 is section 22 across the axis of FIG. 1.
  • FIG. 3 shows a section through an exploded assembly of another embodiment of suitable apparatus.
  • FIG. 4 is a typical assembly of a spacer and electrode used in apparatus of FIG. 3.
  • FIG. 5 shows a typical face configuration of projections on the electrodes in FIGS. 3 and 4.
  • FIG. 6 shows alternate shapes and arrangements of projections on the electrodes in FIGS. 3 and 4.
  • FIG. 7 shows a schematic arrangement of equipment in a continuous process for making hydroquinone from benzene.
  • the process of this invention uses at least one electrolytic cell having an anode and a cathode and having an ion-permeable membrane interposed between them such as to form an anode chamber and a cathode chamber on opposite sides of the membrane.
  • This integrated process reuses both anolyte and catholyte as such. It uses benzene as raw material to be oxidized to quinone and as a liquid carrier for the quinone to be reduced to hydroquinone at the cathode. The residual benzene phase, depleted in quinone, is returned from the cathode chamber to the anode chamber to become enriched in quinone. Make-up benzene is added for oxidation at the anode to replace benzene consumed as hydroquinone.
  • a dispersion of benzene in an aqueous anolyte is anolyzed so as to produce a quinone-enriched benzene phase while a dispersion of the quinone-enriched benzene phase in an aqueous catholyte is catholyzed so as to produce a benzene phase of lowered quinone content and an aqueous catholyte containing hydroquinone formed by reduction.
  • Quinone-enriched benzene phase is separated from aqueous anolyte and dispersed in aqueous catholyte.
  • Benzene phase of lowered quinone content is separated from aqueous catholyte and dispersed in aqueous anolyte. These transfers of benzene phases can be made in batch operations between the two electrolyzing chambers at specified time intervals or, preferably, they can be made continuously in a continuously operating process.
  • I-Iydroquinone formed is chiefly in the aqueous catholyte and in minor proportions is in the benzene phase of lowered quinone content.
  • I-Iydroquinone can be allowed to accumulate in aqueous catholyte and can then be recovered by concentrating and/or chilling the catholyte when enough hydroquinone has been formed.
  • Hydroquinone can be recovered from the benzene phase by extracting with water prior to returning it to the anolyte and then crystallizing it from the extract.
  • a preferred embodiment of this process is to flow the dispersion of a benzene phase along the surface of the appropriate electrode.
  • the velocity is sufficient to displace desired product at the electrode surface with new reactant. Normally the velocity is at least 375 cm. per minute and preferably 875 to 4,500 cm. per minute.
  • the velocity can be any higher rate at which contact with liquid phase is preserved.
  • a more preferred embodiment of this process is to flow the dispersed benzene phase along the appropriate electrode which has an expanded electrochemically active surface.
  • Typical of such an electrode is one provided with projections perpendicular to its broad face. With such an electrode, the dispersed benzene phase is flowed along the anode while the projections are pointed in a direction perpendicular to the general direction of flow. Flow along such an electrode is especially beneficial to anodic oxidation of benzene.
  • This process can be carried out as a continuous process.
  • the quinone-enriched benzene phase produced at the anode is continuously separated from the aqueous anolyte and a portion of the separated benzene phase is continuously led away to be dispersed in the aqueous catholyte.
  • the catholyzed dispersion of benzene phase is continuously separated from the catholyte containing hydroquinone.
  • the benzene phase which has been depleted of its quinone content, and nonnally contains a proportion of the hydroquinone forned at the cathode, is optionally water-extracted to remove its hydroquinone content, and is recycled for redispersion in aqueous anolyte.
  • FIG. 1 shows an axial section of a circular electrolysis cell and consists of shells i and 2 clamped together by means not shown on either side of diaphragm 3.
  • the diaphragm 3 is an ion-conductive, semipermeable membrane separating the cell into an anode compartment and a cathode compartment, and is capable of passing currentcarrying ions while segregating the anode reaction products from the cathode compartment and the cathode reaction products from the anode compartment.
  • Circular anode 4 and cathode 5 are provided with projections 6 arranged as shown in FIG. 2.
  • Anode 4 has central hole 7 through which anolyte can be introduced for radial flow through the space bounded by the diaphragm 3 and the anode 4.
  • Cathode 5 has central hole 8 through which catholyte can be introduced through the space bounded by the diaphragm 3 and the cathode 5.
  • Clear space 9 around the periphery of anode 4 and clear space 10 around the periphery of cathode 5 provide outlets for anolyte to chamber 11 and for catholyte to chamber 12.
  • Inlet 13 directs anolyte, forced from a source not shown, through the center of anode 4 at suitable velocity in a radial path through space between projections 6 of anode 4. Sealing means 14 prevents anolyte leakage from shell 1 or around inlet 13.
  • Projection 15 is electrically integral with anode 4 and insulated from shell 1 by seal 16.
  • Vertical outlet 17 and recycle outlet 18 positioned as shown ensure a liquidfull chamber 11 and allow anolyte flow to a hold tank, not shown, from which anolyte is recycled through inlet 13.
  • Chamber 12 is provided with similar closures, inlets, seals and recirculating means not shown for recirculating catholyte in like manner.
  • FIG. 3 showing a section through an exploded electrolysis cell assembly, uses a bipolar arrangement of electrodes with projections.
  • the cell uses monopolar end electrodes, anode 21 and cathode 22, and bipolar electrode 23 separated by current permeable diaphragms 24 and 25.
  • Each electrode is provided with projections as shown schematically.
  • Electrically insulating spacers 26, 27, 28 and 29 have thicknesses equal to the heights of projections on anode 21, cathode 22 and electrode 23 so that the projections can just touch ion-conductive diaphragms 24 and 25 in the assembled cell.
  • Supporting plates 30 and 31 are drawn together by means not shown around interposed insulating plates 32 and 33.
  • FIG. 4 shows electrode 21 positioned against spacer 26.
  • Cutout 34 in spacer 26 provides communicating space between anode 21 and alined entry holes in anode 21 and insulating plates, not shown, to allow anolyte entry to anode 21.
  • Cutout 35 in spacer 26 provides communicating space between anode 21 and alined entry holes in anode 21 and insulating plates, not shown, to allow anolyte exit from anode 21.
  • Similar cutouts in space 28 of FIG. 3 provide communicating space between the anode portion of electrode 23 and alined entry holes in diaphragm 24, spacer 27 and electrode 23 to also allow anolyte to exit from the anode portion of electrode 23.
  • the alined holes for anolyte entry and exit can be lined with an insulating sleeve, not shown, to avoid electrical losses through the anolyte.
  • Like selective flow means not shown, allow catholyte flow along cathode 22 and the cathode side of electrode 23 by using like entry and exit arrangements and passages alined to accommodate catholyte flow through plate 31, plate 33, cathode 22, spacer 29, diaphragm 25, spacer 28 and electrode 23.
  • FIG. 5 shows typical electrode projections of anode, electrode and cathode.
  • the projections can be cylindrical or other shape such as projected square shape both as shown in FIG. 6.
  • Aqueous anolyte which settles in settler 43 is recycled to the anode chamber 42 through heat exchanger 58.
  • Benzene phase from settler 43 enriched in quinone, is pumped by pump 44 into the aqueous catholyte and dispersed therein by pump 45. The dispersion is moved through the cathode chamber 46, then to the liquid-liquid settler 47.
  • Aqueous catholyte which settles in settler 47 is recycled to cathode chamber 46 through heat exchanger 59.
  • Benzene phase from the settler 47, containing hydroquinone is passed to the liquid-liquid extractor 48 where the benzene phase is extracted with water.
  • the benzene phase now essentially free of hydroquinone, is recycled to pump 49 along with a small benzene make-up from source 50, and recycled through the anode chamber 42.
  • Water reclaimed by condenser 52 is recycled through pump 53, along with needed make-up water from source 54, through extractor 48.
  • Vapors from settlers 43 and 47 are vented to condenser 55 where noncondensibles exit through stack 57 and condensate is recycled via tank 56 to anode chamber 42.
  • Potentials in the electrolyzing cells are in the 2.5 to volt range and preferably are in the 2.5 to 7 volt range.
  • Current densities normally range from 4 to 31 amperes per square decimeter, and preferably from 5 to 16 amperes per square decimeter of electrically active anode or cathode surface. Current density can be increased when flow velocity along an electrode is increased without a penalty in current efficiency of the oxidation or reduction.
  • Temperatures of the electrolytic reactions are conveniently 10 to 60C, and preferably are 25 to 40C.
  • Electrolytes used should have low electrical resistance. They are aqueous solutions comprising acids exemplified by aqueous phosphoric and, preferably, sulfuric acid, normally containing up to 20%, preferably 5 to 10% by weight of the acid.
  • Dispersions of benzene phases used normally contain 5 to 25%, and preferably 10 to by volume of benzene. They can be produced by the mixing action of the pumps moving them and maintained by their movement along electrode surface.
  • the benzene solution of hydroquinone separated as a distinct phase from the catholyte can be extracted by small proportions of water and the benzene can then be recycled for use at the anode.
  • the catholyte will contain a member of a suitable redox couple in an amount effective to accelerate the reduction rate without increasing current.
  • a suitable redox couple comprises an oxidized form and a reduced form both of which are soluble in the catholyte. It is only required that the oxidized form be electrochemically reducible to the reduced form under the process conditions and that the reduced form be capable of chemically reducing quinone'to hydroquinone and thereby be converted back to the oxidized form. More particularly suitable, redox couples are those which can be converted from the reduced to the oxidized form at a standard potential at least as positive as 0.7 volt.
  • Typical redox systems are Fe( CN) Fe(CN Sn Sn, AsO; AsOf, TiO Ti and, preferably Cr Cr.
  • Typical concentrations are 0.02 to 0.2, preferably 0.04 to 0.15, gram atom equivalent per liter of catholyte.
  • a gram atom equivalent is the gram molar amount of one form divided by the valence change on conversion to the other form.
  • redox couples in the anolyte can also be employed to advantage in this process. Suitable in this process is the use of the Cr" Cr couple in concentrations of 0.03 to 0.3 gram atom equivalent per liter of anolyte, such as is provided by 0.9 to 9 grams CrO per liter of anolyte.
  • a member of the redox couple is added as a suitable salt whose complementary anion or cation provides solubility in the catholyte and does not interfere with the process.
  • Variable valent cationic redox systems are conveniently added as their sulfates.
  • Variable valent anionic systems are most conveniently added as their group IA metal salts. Either redox form can be added. If the reduced form is added, it will react in situ with quinone and be converted to the oxidized form which can then be reduced at the cathode to the reduced form for further reaction with quinone.
  • Redox couple use as defined assures increased hydroquinone formation from quinone without increased current use. Complete quinone reduction in the absence of a redox couple is slow and often requires more ampere hours than quinone formation from benzene, though its theoretical requirement is one-third that required for quinone formation from benzene.
  • An integrated batch process using enough redox couple in the catholyte can enable complete reduction of a batch of quinone to hydroquinone at the cathode during the production at the anode of a like batch of quinone.
  • An integrated continuous process with sufficient redox couple in the catholyte can almost completely reduce quinone sent to the cathode and maintain a relatively low quinone content at the anode because little unreduced quinone is recycled to the anode.
  • the effect of keeping a low quinone content at the anode is to increase current efficiency of its production by avoiding the further oxidation of quinone, the desired anodic product, and to extend the useful life of the continuously recycled anolyte.
  • EXAMPLE 1 Apparatus was arranged essentially as in FIG. 7 except that the quinone-enriched benzene phase from settler 47 was sent directly to pump 49 and elements 48, 51, 52, 53 and 54 were not used.
  • the anolyte system was charged with 640 cc. 5% aqueous sulfuric acid containing 5 grams CrO and 400 cc. benzene, part of which was dispersed in the acid.
  • the catholyte system was charged with 550 cc.
  • the electrodes had cast-in lead projections 1/16 inch in diameter, /8 inch high and triangularly arranged [ainch center-to-center.
  • the electrodes were mounted with heads of the projections against a diaphragm like that used in Examples 2 to 7.
  • nil less than 0.015 gm.
  • Example 16a parable volume flow rates and comparable current densities
  • Example 16b clearly shows improvement in current efv ficiency due to increased flow velocity over Example 16a.
  • Example 17 shows that despite increased current density the current efficiency is higher than in Example 15, which is attributed to the greater flow velocity.
  • the dispersion of benzene was ducing benzene enriched with quinone while pumped past the anode for 90 minutes under selected B. simultaneously catholyzing a dispersion in aquecurrent application to a hold tank and recycled along ous catholyte of benzene phase enriched with quithe anode while 0.5 molar sulfuric acid filled the cathnone at the cathode electrode, thereby producing ode chamber.
  • volume flow was raised for last half.
  • Example 15 By comparing Example 15 with Example 16a at com- D. separating the benzene phase of lowered quinone content from the aqueous catholyte phase and dispersing it in the aqueous anolyte, and
  • the aqueous catholyte contains at least one member of a redox couple, which can be converted from the reduced to the oxidized form at a standard potential at least as positive as 0.7 volts, in an amount sufficient to accelerate the reduction of quinone to hydroquinone, the couple comprising an oxidized and a reduced form wherein A. both the oxidized and reduced forms are soluble in the catholyte,
  • the oxidized form is electrochemically reducible to its reduced form
  • the reduced form is capable of chemically reducing quinone to hydroquinone and thereby be converted to the oxidized form.
  • steps (A) and (B) are carried out with a flowing dispersion at the electrode.
  • step (A) and step (B) electrodes has an expanded electrically active surface.
  • step (D) A process of claim 1 wherein the benzene phase of step (D) is extracted with water before its dispersion in the anolyte.
  • the expanded electrically active surface has a multiplicity of projections disposed such that they are pointed in a direction perpendicular to the flow of dispersion along the electrode.
  • a process of claim 6 wherein the electrodes have benzene phase of lowered quinone content is continuously separated from the catholyte and is dispersed in the anolyte.

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Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4071429A (en) * 1976-12-29 1978-01-31 Monsanto Company Electrolytic flow-cell apparatus and process for effecting sequential electrochemical reaction
US4462876A (en) * 1983-03-25 1984-07-31 Ppg Industries, Inc. Electro organic method and apparatus for carrying out same
US4464236A (en) * 1982-05-10 1984-08-07 The Dow Chemical Company Selective electrochemical oxidation of organic compounds
US4472251A (en) * 1983-03-25 1984-09-18 Ppg Industries, Inc. Electrolytic synthesis of organic compounds from gaseous reactant
US4472252A (en) * 1983-03-25 1984-09-18 Ppg Industries, Inc. Electrolytic synthesis of organic compounds from gaseous reactants
US4543173A (en) * 1983-05-12 1985-09-24 The Dow Chemical Company Selective electrochemical oxidation of organic compounds
US4636286A (en) * 1983-03-25 1987-01-13 Ppg Industries, Inc. Electro organic method
US5009869A (en) * 1987-12-28 1991-04-23 Electrocinerator Technologies, Inc. Methods for purification of air
US5114544A (en) * 1988-09-26 1992-05-19 Imperial Chemical Industries Plc Production of fluorocarbons
WO2003006714A1 (en) * 2001-07-10 2003-01-23 Pinnacle West Capital Corporation System and method for removing a solution phase metal from process liquor

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0728318U (ja) * 1993-11-05 1995-05-30 進 垂井 草刈払機の刈刃保護装置
CN1048956C (zh) * 1996-05-14 2000-02-02 汪承源 二次结晶超细白炭黑的制法

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1322580A (en) * 1919-11-25 Method and apparatus for producing quinone and quinol
US3423300A (en) * 1967-10-25 1969-01-21 Great Lakes Carbon Corp Electrolytic regeneration of reduced chromium compounds
US3721615A (en) * 1971-02-24 1973-03-20 Union Rheinische Braunkohlen Process for the production of hydroquinone

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1322580A (en) * 1919-11-25 Method and apparatus for producing quinone and quinol
US3423300A (en) * 1967-10-25 1969-01-21 Great Lakes Carbon Corp Electrolytic regeneration of reduced chromium compounds
US3721615A (en) * 1971-02-24 1973-03-20 Union Rheinische Braunkohlen Process for the production of hydroquinone

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4071429A (en) * 1976-12-29 1978-01-31 Monsanto Company Electrolytic flow-cell apparatus and process for effecting sequential electrochemical reaction
US4464236A (en) * 1982-05-10 1984-08-07 The Dow Chemical Company Selective electrochemical oxidation of organic compounds
US4462876A (en) * 1983-03-25 1984-07-31 Ppg Industries, Inc. Electro organic method and apparatus for carrying out same
US4472251A (en) * 1983-03-25 1984-09-18 Ppg Industries, Inc. Electrolytic synthesis of organic compounds from gaseous reactant
US4472252A (en) * 1983-03-25 1984-09-18 Ppg Industries, Inc. Electrolytic synthesis of organic compounds from gaseous reactants
US4636286A (en) * 1983-03-25 1987-01-13 Ppg Industries, Inc. Electro organic method
US4543173A (en) * 1983-05-12 1985-09-24 The Dow Chemical Company Selective electrochemical oxidation of organic compounds
US5009869A (en) * 1987-12-28 1991-04-23 Electrocinerator Technologies, Inc. Methods for purification of air
US5114544A (en) * 1988-09-26 1992-05-19 Imperial Chemical Industries Plc Production of fluorocarbons
WO2003006714A1 (en) * 2001-07-10 2003-01-23 Pinnacle West Capital Corporation System and method for removing a solution phase metal from process liquor
US6685819B2 (en) 2001-07-10 2004-02-03 Pinnacle West Capital Corporation System and method for removing a solution phase metal from process liquor

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