EP1458924A1 - Procede et appareillage pour l'hydrogenation electrocatalytique de colorants de cuve et de colorants au soufre - Google Patents

Procede et appareillage pour l'hydrogenation electrocatalytique de colorants de cuve et de colorants au soufre

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Publication number
EP1458924A1
EP1458924A1 EP02782627A EP02782627A EP1458924A1 EP 1458924 A1 EP1458924 A1 EP 1458924A1 EP 02782627 A EP02782627 A EP 02782627A EP 02782627 A EP02782627 A EP 02782627A EP 1458924 A1 EP1458924 A1 EP 1458924A1
Authority
EP
European Patent Office
Prior art keywords
dye
cathode
hydrogenation
electrochemical reaction
adsorbed
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.)
Withdrawn
Application number
EP02782627A
Other languages
German (de)
English (en)
Inventor
Walter Marte
Otmar Dossenbach
Albert Roessler
Ulrich Meyer
Paul Rys
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
TEX-A-TEC AG
TEX A TEC AG
Original Assignee
TEX-A-TEC AG
TEX A TEC AG
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Publication date
Application filed by TEX-A-TEC AG, TEX A TEC AG filed Critical TEX-A-TEC AG
Publication of EP1458924A1 publication Critical patent/EP1458924A1/fr
Withdrawn legal-status Critical Current

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Classifications

    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06P—DYEING OR PRINTING TEXTILES; DYEING LEATHER, FURS OR SOLID MACROMOLECULAR SUBSTANCES IN ANY FORM
    • D06P1/00—General processes of dyeing or printing textiles, or general processes of dyeing leather, furs, or solid macromolecular substances in any form, classified according to the dyes, pigments, or auxiliary substances employed
    • D06P1/22—General processes of dyeing or printing textiles, or general processes of dyeing leather, furs, or solid macromolecular substances in any form, classified according to the dyes, pigments, or auxiliary substances employed using vat dyestuffs including indigo
    • D06P1/221—Reducing systems; Reducing catalysts
    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06P—DYEING OR PRINTING TEXTILES; DYEING LEATHER, FURS OR SOLID MACROMOLECULAR SUBSTANCES IN ANY FORM
    • D06P1/00—General processes of dyeing or printing textiles, or general processes of dyeing leather, furs, or solid macromolecular substances in any form, classified according to the dyes, pigments, or auxiliary substances employed
    • D06P1/22—General processes of dyeing or printing textiles, or general processes of dyeing leather, furs, or solid macromolecular substances in any form, classified according to the dyes, pigments, or auxiliary substances employed using vat dyestuffs including indigo
    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06P—DYEING OR PRINTING TEXTILES; DYEING LEATHER, FURS OR SOLID MACROMOLECULAR SUBSTANCES IN ANY FORM
    • D06P1/00—General processes of dyeing or printing textiles, or general processes of dyeing leather, furs, or solid macromolecular substances in any form, classified according to the dyes, pigments, or auxiliary substances employed
    • D06P1/30—General processes of dyeing or printing textiles, or general processes of dyeing leather, furs, or solid macromolecular substances in any form, classified according to the dyes, pigments, or auxiliary substances employed using sulfur dyes
    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06P—DYEING OR PRINTING TEXTILES; DYEING LEATHER, FURS OR SOLID MACROMOLECULAR SUBSTANCES IN ANY FORM
    • D06P5/00—Other features in dyeing or printing textiles, or dyeing leather, furs, or solid macromolecular substances in any form
    • D06P5/20—Physical treatments affecting dyeing, e.g. ultrasonic or electric
    • D06P5/2016—Application of electric energy

Definitions

  • the present invention relates to a process for the electrocatalytic hydrogenation of vat and sulfur dyes in aqueous solutions according to claim 1 and an apparatus for carrying out this process according to claim 15.
  • Vat and sulfur dyes are applied to textile materials in the reduced form, since only this is water-soluble and has a high affinity for substrates. As a result of the oxidation carried out after dyeing, the dye is converted from its leuco form back into the water-insoluble pigment structure.
  • vat and sulfur dyes for printing and dyeing textile fibers has hitherto been linked to the use of overstoichiometric amounts of reducing agent (based on the amount of dye to be reduced).
  • the vat dyes are usually reduced in alkaline (pH> 9), aqueous solutions with sodium dithionite (hydrosulfite) or reducing agents derived from them (e.g. RONGALIT C, BASF) in conjunction with wetting agents and complexing agents.
  • reducing agents such as thiourea dioxide or endiolates have barely become established for cost reasons.
  • the reducing agents suitable for reducing the vat dyes show a redox potential of -400 mV to -1000 mV under the conditions necessary for the vatting of the dyes.
  • Both the use of hydrosulfite and thiourea dioxide lead to a high sulfite or sulfate load in the waste water. These Saiz loads are toxic on the one hand and corrosive on the other hand and lead to the destruction of concrete pipes.
  • Another problem of the sulfate load in the wastewater resulting from the sulfite is the formation of hydrogen sulfide in the sewer pipes caused by anaerobic organisms. Even newer methods were only able to partially solve the problems mentioned.
  • the mediators are reversible redox systems such as iron (II / III) complexes that reduce the dye and are constantly regenerated at the cathode. Due to the high amounts used and the ecological concern of such mediators, there is still an acute environmental problem that can only be solved by additional investments in adequate wastewater technology or by a recycling process. Another disadvantage of these processes is the permanent addition of mediators to maintain the redox cycle in continuous dyeing. The replenishment of the mediator system results from the discharge of the liquor, which is proportional to the tissue or the graft flow.
  • a "method for the electrochemical reduction of vat dyes is known from WO 01/46497 is known, which is based on the method described in EP 0808920-B1 process principle of so-called precoat-layer-cell.
  • the dye having a cathode comprising a porous, electrically conductive and filter-shaped support and an electrically conductive, cathodically polarized layer formed thereon by precoating, brought into contact in the presence of a base and electrochemically reduced by the application of voltage formed layer stabilized.
  • solubilizing agents which is state-of-the-art and necessary for rapid coupling with high degrees of conversion, and in particular the use of ultrasound to produce a much more homogeneous and fine-grained distribution of the color pigments, would lead to very large pressure losses and to blockage of the electrode designed as a filter ,
  • Electrocatalytic hydrogenation using nickel or similar large-area, conductive, catalytically active materials with low hydrogen overvoltage is a long-known method and has been successfully applied to numerous organic compounds.
  • Platinum, nickel, palladium and Rhodium was used for the hydrogenation of acetophenone (SJC Cleghom, D. Pletcher, Electrochim. Acta 1993, 38, 425-430), palladium in alkenes (K. Junghans, Chem. Ber. 1974, 107, 3191-3198) and palladium as well Nickel for the hydrogenation of nitrobenzene (SJC Cleghorn, D. Pletcher, Electrochim. Acta 1993, 38, 2683-2689).
  • Nickel surfaces are very often used because of the low cost and the relatively simple possibility of forming extremely large surfaces (Raney nickel).
  • This type of electrode has been successfully used for the electrocatalytic hydrogenation of unsaturated hydrocarbons such as polycyclic compounds (D. Robin, et. Al., Can. J. Chem. 1990, 68, 1218-1227), phenols (A. Martel, et. Al., Can J. Chem. 1997, 75, 1862-1867), ketones (P. Dabo, et.
  • Raney nickel aluminum alloy US 4,302,322
  • Raney copper aluminum alloy US 4,584,069
  • PTFE polytetrafluorethylene
  • the object of the present invention is to provide a completely reducing agent-free coupling process for the production of fully reduced dye solutions while avoiding the disadvantages of known reduction processes mentioned.
  • Another object of the invention is to provide an apparatus for performing this method.
  • FIG. 1 Schematic representation of an apparatus for continuous, electrocatalytic veining
  • Vat dyes for the purposes of the present invention include, in addition to the indigo dyes, indigo itself being preferred, also anthraquinones, and sulfur and other vat dyes. They are referred to below as dye A, which is usually present as a dye pigment.
  • the process is essentially based on the electrocatalytic hydrogenation of dye A to the reduced dye species P, further briefly referred to as species P, which represents the leuco form of dye A (reaction equations I - IV). This involves the formation of adsorbed hydrogen on the cathode (I) and the hydrogenation process known from catalytic hydrogenation (II - IV):
  • the radical species occurring under certain conditions during the hydrogenation can be hydrogenated in an analogous manner. In contrast to the process described in WO 00/31334, however, they are not necessary to maintain the reaction, since the dye A itself is electrocatalytically hydrogenated directly at the electrode.
  • the electrocatalytic hydrogenation differs clearly from the so-called electrochemical hydrogenation. This is because electrochemical hydrogenation relates to a process which takes place on an electrode with little or no catalytic hydrogenation activity, a small surface area and a large hydrogen overvoltage, with electrons being transferred directly to the substrate.
  • the electrocatalytic hydrogenation is carried out using a conductive, catalytically active electrode with a large surface area and low hydrogen overvoltage, which simultaneously acts as an electrode for the electrochemical generation of adsorbed hydrogen atoms and as a hydrogenation catalyst for the reduction of the dye.
  • the hydrogen produced is ideally not formed in molecular form, i.e. does not desorb from the cathode and readsorb on the catalyst, but the reaction takes place simultaneously with the generation of the adsorbed hydrogen atoms on the same cathodic surface.
  • the method according to the invention also differs from a process in which electrochemically produced, gaseous hydrogen is used for the catalytic hydrogenation of organic substances.
  • this catalytic hydrogenation requires two separate reaction steps - first the electrochemical hydrogen production, then the purely chemical, catalytic hydrogenation - in spatially separate reactors.
  • the dye is hydrogenated in an oxygen-free, electrochemical reaction cell.
  • Various cell connections allow continuous and batch operation of the electrolysis equipment.
  • the dye A is introduced on the cathode side in an aqueous suspension containing various additives into an electrolysis vessel or into a catholyte tank.
  • the alkaline pH value required for dye hydrogenation is pH 9 to 14, preferably 12 to 13, and is combined with alkali hydroxide, in particular sodium hydroxide. solutions set.
  • the acidic or alkaline anolyte which is spatially separated by a separator (eg membrane, diaphragm), preferably consists of an aqueous solution of sulfuric acid or alkali hydroxide.
  • dye-related solubilizing or dispersing agents are used as additives:
  • Alcohols e.g. Methanol, ethanol, iso-propanol, with methanol and iso-propanol being particularly preferred,
  • Acetals e.g. Glycol ether, propylene glycol, ethylene glycol monomethyl, ethyl or butyl ether, diethylene glycol monomethyl or ethyl ether,
  • Pyridines e.g. Pyridine and ⁇ -, ß- and ⁇ -picolines
  • Lactams such as Pyrrolidone, N-methylpyrrolidone and 1, 5-dimethylpyrrolidone,
  • Naphthalenesulfonic acid derivatives such as for example " .
  • Setamol WS naphthalenesulfonate condensed with formaldehyde
  • additives are used in amounts of approximately 0.1 to 90%, preferably 1 to 30%, based on the dye composition used.
  • ultrasound has proven itself as a dispersion aid.
  • the suspension is subjected to ultrasonic energy during or before the hydrogenation of the dye.
  • ionic or non-ionic surfactants and protic and aprotic solvents are also used as additives which have both affinity for dye and electrode and do not themselves have a reducing effect.
  • Typical representatives of these substances are alcohol propoxylates such as e.g. Lavotan SFJ, alcohol sulfates such as e.g. Sandopan WT, Subitol MLF and alkyl sulfonates such as Levapon ML.
  • the amounts used of these additives are in the range from 0.1 to 10 g / l, preferred concentrations are between 1 and 5 g / l.
  • auxiliaries for adjusting the conductivity of the Electrolyte solutions used are used as auxiliaries.
  • Salts of metal cations such as sodium, potassium or tetraalkylammonium ions such as tetramethylammonium and anions such as halide ions, sulfates or sulfonates such as toluenesulfonate are used as auxiliary substances.
  • the content is about 0.1 to 10% by weight, preferably 1-5% by weight.
  • all electrically stable, large-area, catalytically active materials with low hydrogen overvoltage that are stable in the alkaline range (pH 9 to 14) can be used as the cathode material.
  • metals such as Raney copper, cobalt, molybdenum, platinum black, ruthenium black and palladium black or corresponding active Raney alloys (for example Raney nickel molybdenum and nickel molybdenum), Raney nickel preferably being used. These are usually applied to different electrically conductive carrier materials and configured as an electrode.
  • suitable supports are metals such as nickel, V2A steel or carbon, which are used as porous, perforated materials such as nets, expanded metal sheets, grids and smooth sheets.
  • a bed of conductive particles can also serve as the carrier.
  • the current is supplied via a contact electrode.
  • This bed of particles is located in a flow channel and the electrolyte flows through it, whereby entrainment or the removal of particles is avoided.
  • the catalytically active layer is permanently fixed on the carrier particles.
  • the particle bed is flowed through from bottom to top, for example. If the inflow velocity exceeds the so-called loosening velocity, there is a fluidized bed, while the electrode works as a fixed bed at low velocities.
  • a cathode consisting of graphite granules alone shows a similarly advantageous electrochemical reduction behavior.
  • the selection of the anode material is not very critical, but depends on the solvent of the anolyte. Possible materials are, for example, graphite, iron, nickel, platinum, titanium coated with platinum and titanium coated with ruthenium oxide.
  • the voltage applied to the electrodes is a function of the hydrogen overvoltage of the respective electrode material and also depends on the reaction medium. Usually cell voltages between 1 to 5 V, preferably between 2 and 3 V, applied.
  • the current densities are 50-1000 A / m 2 , preferably 100-2000 A / m 2 . In addition to using a constant current, it is also possible to use pulsating currents.
  • the process is usually carried out at atmospheric pressure and temperatures between 20 and 100 ° C, preferably between 25 and 60 ° C.
  • the electrocatalytic hydrogenation can be carried out both in a batch and in a continuous reactor, the construction of which is considerably simpler and cheaper compared to normal hydrogenation reactors.
  • the electrochemical reaction cell can also be designed as a pressure vessel and can be operated at pressures of 1-10 bar, preferably 1-6 bar. The pressure drop across the electrochemical reaction cell remains essentially constant over time. There is no blockage, which eliminates the need for backflushing through flow reversal.
  • the method according to the invention achieves surprising advantages in the field of dyeing textile materials with vat and sulfur dyes, in particular indigo.
  • the coupling technique described allows a new start of the reaction, even after longer downtimes, without any addition of reducing agents.
  • Controlling the formation of hydrogen on the catalyst surface by the flowing current or the applied voltage leads to the avoidance of an over-reduction of the dye, as is very often the case with hydrosulfite and thiourea dioxide as reducing agents.
  • dye concentrations can reach up to 200 g / l, but preferably 80-120 g / l, can be achieved in the stock vats.
  • the high level of dye solubility is of particular importance, as color overflows in the dyebaths can be prevented by means of more concentrated stock pools.
  • Warp yarns that are dyed with these solutions are characterized by good rub fastness and a high weaving factor. Further advantages are the high stability of the reduced vat fleet in the oxygen-free electrolysis vessel, the high dye solubility of the linked species, the continuous dye reduction and thus the "just in time" - preparation of the dye solution.
  • the electrocatalytic hydrogenation according to the invention is suitable both for color master batches and for dye liquors.
  • the enormous economic advantage lies in the reduction in the consumption of chemicals (reducing agents and sodium hydroxide solution), the manufacture of a better quality product and significantly lower wastewater costs due to the existing biocompatibility of the remaining wastewater constituents. There are no toxic loads on the waste water side, which makes it possible to recycle the waste water with significantly lower expenditure compared to conventional dyeing systems.
  • the process according to the invention has the following advantages over the known catalytic hydrogenation: (1) the kinetic barrier of the splitting of the hydrogen molecule is completely avoided; (2) the inhibition of transport of the poorly soluble hydrogen is also avoided; (3) hydrogen and the catalyst material are used much more efficiently, which means that less loading of the reactor with active catalyst is necessary; (4) only small amounts of gaseous hydrogen are released, which minimizes the risk of explosion and the risk of fire; (5) the formation of hydrogen arf on the catalyst surface can be controlled and controlled much more easily by the flowing current or the applied voltage, which leads to improved product selectivity and possibly avoids so-called over-reduction of the dye; (6) the operating temperature is low and (7) no pressure vessels and compressors are required to transport the gaseous hydrogen.
  • Dithionite and its derivatives e.g. Formaldehyde sulfoxylate (e.g. RONGALIT C, BASF),
  • hydroxy ketones e.g. Monohydroxyacetone, dihydroxyacetone,
  • hydroxy aldehydes e.g. Glycolaldehyde, triose reductone (2,3-dihydroxyacrylic aldehyde or
  • Fig. 1 shows a schematic representation of an apparatus for continuous, electro-catalytic dye hydration.
  • the dye suspension in the catholyte tank 1 with the alkali and the selected additives is circulated in a circulation stream V1 by means of the pump P1 during the entire reaction time in order to avoid sedimentation in the catholyte tank 1.
  • a second circuit branches off a second, substantially constant volume flow V2 measured over time, consisting of second lines 17, 17 'and 17 ", a second pump P2, a steel tube spiral 3, an electrochemical reaction cell 7 and a second inlet tube 6, which is also via returns the lid 1 'to the catholyte tank 1.
  • the steel tube spiral 3 is located on an ultrasonic vibrator 5.
  • the energy input via the ultrasonic vibrator 5 is 100-1000 watts and serves to disperse the dye, the steel tube spiral 3 with the ultrasonic vibrator 5 as Dispersion aid work.
  • a third circuit is provided for the anode, consisting of an anolyte tank 31 with a lid 31 ', tightly closed by means of seals 32, with third lines 18, 18' and 18 ", with a third pump P3 and a third inlet pipe 19, which via the lid 31 'is returned to the anolyte tank 31.
  • the electrochemical reaction cell 7 there is a pair of electrodes separated by a membrane 9, consisting of a cathode 8 and an anode 8', to which an electrical cell voltage of approximately 2 to 3 V is applied. It is usually a normal DC voltage, but pulsating DC voltages are also used.
  • the equipment for continuous hydrogenation equipment is expanded with the equipment additions described below.
  • a second volume flow V5 corresponding to the first volume flow V4 is removed from the catholyte tank 1 and metered by means of a fifth pump P5 via fifth lines 15, 15 'and a fourth inlet pipe 16 into an oxygen-free storage tank 21 which is equipped with the cover 21' and seals 22 is tightly closed.
  • reductant-free, electrocatalytic dye hydrogenation carried out in this way corresponds to the principles of continuous reaction control in an ideally mixed stirred kettle.
  • the apparatus described is suitable for laboratory operation and can be operated with a wide variety of sizes of electrochemical reaction cells.
  • catholyte tanks with a volume of 80 - 500 l are common.
  • Example 1 describes an electrocatalytic hydrogenation of indigo in a batch reactor and the production and activation of the. electrocatalytic hydrogenation electrodes used.
  • a mesh made of stainless steel (square mesh, 250 ⁇ m mesh size) with the outer dimensions of 4 x 10 cm is first cleaned in aqueous alkali (NaOH 30 g / l) at 50 ° C and then in a galvanotechnical step for 15 minutes with a Nickel plated layer.
  • the nickel bath at 50 ° C has the following composition: 300 g / l NiS0 4 - 6H 2 0; 45 g / l NiCI 2 - 6H 2 0; 30 g / l H 3 B0 3 .
  • a nickel sheet is used as the anode.
  • the current density is approximately 1 A / dm 2 .
  • Electrocatalytic hydrogenation In order to optimize the electrocatalytic properties, the electrode must be activated at 70 ° C for about 10 hours in 20% sodium hydroxide solution. This is followed by a washing process with deionized water. Electrocatalytic hydrogenation:
  • the activated electrode 8, 8 ' is installed in an electrochemical batch reactor 7 (H cell) in which the anode and cathode compartments are separated by a membrane 9 (Nation 324, DuPont).
  • indigo is dispersed in 95 ml of water and 5 ml of methanol, which simultaneously contains 4.0 g of sodium hydroxide solution and 2 g of Setamol WS as a dispersant, and is added on the cathode side into the electrolysis vessel 7, which has been thermostated to 50 ° C. After degassing the reaction mixture with nitrogen (99%) for about 2 hours, a cathode potential of -1200 mV vs. Ag / AgCI applied in 3 M KCI solution. A mixture of 95 ml of water and 5 ml of methanol, which contains 4.0 g of sodium hydroxide solution, serves as the anolyte. The working current is about 0.3 A.
  • a coloring solution with a dye concentration of 0.1 g / l is prepared with 20 ml of this stock vial.
  • the dyeing is carried out in the absence of oxygen using 10 g of cotton fabric at a temperature of 30 ° C. for 10 minutes. After the dyeing process is complete, the sample is oxidized in air, rinsed and finally washed at 50 ° C.
  • the sample produced in this way shows a brilliant shade of blue, the color depth is identical to that of a color sample produced by the conventional dyeing method with sodium hydrosulfite.
  • Example 2 describes an electrocatalytic hydrogenation in a flow reactor in filter press design in batch operation.
  • the reactor 7 (Electro MP-Cell, Electrocell AB, Sweden) consists of two anodes 8 '(nickel sheet), which are located on both sides of the central cathode 8. This also consists of a nickel sheet on which several layers of the Raney nickel electrodes known from Example 1 with the outer geometric dimensions of 10 ⁇ 10 cm are spot welded on both sides. The total outer geometric cathode surface is 1 m 2 . Catholyte and anolyte flow vertically through the respective electrode space from bottom to top with a volume flow of 0.6 l / min. A commercially available Nafion membrane 9 (Nation 324, DuPont) is used as the diaphragm.
  • indigo 20 g of indigo are dispersed in 2 l of water, which simultaneously Contains 80 g of sodium hydroxide solution and 4 g of Setamol WS (BASF) as a dispersant.
  • 2 l of water, which contains 80 g of sodium hydroxide solution are introduced on the anode side.
  • the hydrogenation of the dye suspension is carried out at 30 ° C. in the reactor after appropriate degassing with nitrogen (99%) by simply applying a cathode potential of -1200 mV vs. Ag / AgCI reached in 3 M KCI solution.
  • the working current is approximately 3 A.
  • the dyeings made with this solution meet all criteria (depth of color and fastness) as they are achieved with conventionally produced vat dye liquors.
  • Example 3 describes a continuous electrocatalytic hydrogenation in one
  • batch hydrogenation is carried out analogously to Example 2.
  • a 1, 75% dye suspension is then from the storage tank 11 in the
  • Circulation flow V1 is conveyed by means of the fourth pump P4 with a first volume flow V4 of 10 ml / min.
  • the indigo suspension in the storage tank 11 has the same composition as that described at the beginning.
  • a second volume flow V5 of 10 ml / min corresponding to the paint inlet or the volume flow V4 is taken from the catholyte tank 1 and in the oxygen-free
  • Storage tank 21 metered by means of the fifth pump P5.
  • Example 4 describes a continuous electrocatalytic hydrogenation on an industrial scale in a flow-through reactor in a filter press construction.
  • the reactor 7 consists of ten reaction cells connected in parallel in a filter press construction (Electro Prod-Cell, Electrocell AB, Sweden), each consisting of two anodes 8 '(nickel sheet), which are located on both sides of the centrally located cathode 8.
  • This also consists of a nickel sheet on which several layers of the Raney nickel electrodes described in Example 1 with the outer geometric dimensions of 60 x 60 cm are spot welded on both sides.
  • the total outer geometric cathode surface of the reactor is 120 m 2 .
  • the catholyte flows vertically through the respective reaction cells from bottom to top with a volume flow V1 of 20 l / min.
  • a commercially available Nafion membrane 9 (Nation 324, DuPont) is used as the diaphragm between the individual cells.
  • batch hydrogenation is carried out analogously to Examples 2 and 3.
  • indigo 20 kg of indigo are dispersed in a mixture of 190 l of water and 10 l of methanol, which simultaneously contains 8 kg of sodium hydroxide solution and 800 g of Setamol WS (BASF) as a dispersant.
  • 200 l of water, which contains 8 kg of sodium hydroxide solution are introduced on the anode side.
  • the hydrogenation of the dye suspension is carried out at 60 ° C. in the reactor after corresponding degassing with nitrogen by simply applying a cathode potential of -1200 mV vs. Ag / AgCI reached in 3 M KCI solution. These conditions are maintained for 24 hours to fully hydrogenate dye A.
  • An indigo suspension with 100 g / l is then conveyed from the storage tank 11 into the circulation flow V1 by means of the pump P4 with a volume flow V4 of 2.5 l / min.
  • the indigo suspension in the storage tank 11 has the same composition as that described at the beginning.
  • a volume flow V5 of 2.5 l / min corresponding to the paint inlet V4 is taken from the catholyte tank 1 and metered into the oxygen-free storage tank 21 by means of the pump P5.
  • the indigo stock vat available in the storage tank is used with a volume flow of 1.75 l / min in the dye bath to dye a warp game det.
  • the warp yarn the weight of which is 250 g / lm, is continuously dyed at a speed of 35 m / min for 8 hours. Due to the general conditions on the warp dyeing machine and the supplied vat volume flow of 1.75 l / min, there is a 2% dyeing (based on the warp yarn weight).
  • Example 5 describes an electrocatalytic hydrogenation in a fixed bed reactor in batch operation.
  • the reactor 7 consists of a cathode 8, which is designed as a bed electrode. 50 g of nickel balls with a diameter of 1 mm are used as the electrode material, which were previously electroplated with a layer of platinum black. Below is a platinum network as a contact electrode. The balls are located in a flow channel made of glass (cross section 7 cm 2 ) between two sieves (mesh size 0.5 mm). Anode 8 '(DeNora DSA) with an electrode area of 20 cm 2 is located in the anode space, which is spatially separated by a membrane 9 (Nation 324, DuPont). 2% sulfuric acid, which is not circulated, serves as the anolyte.
  • a membrane 9 (Nation 324, DuPont).
  • Example 6 describes an electrocatalytic hydrogenation in a fluidized bed reactor in a batch business.
  • the reactor 7 consists of a cathode 8, which is designed as a bed electrode. 50 g of nickel balls with a diameter of 1 mm are used as the electrode material, which were previously electroplated with a layer of platinum black. Below is a platinum network as a contact electrode. The balls are located in a flow channel made of glass (cross-section 7 cm 2 ) between two sieves (mesh size 0.5 mm), but there is enough space above the bed to not hinder expansion of the fluidized bed. Anode 8 '(DeNora DSA) with an electrode area of 20 cm 2 is located in the anode space, which is spatially separated by a membrane 9 (Nation 324, DuPont). 2% sulfuric acid, which is not circulated, serves as the anolyte.
  • a membrane 9 (Nation 324, DuPont).
  • Example 7 describes an electrocatalytic hydrogenation on a rotating fixed bed electrode in batch operation.
  • the reactor 7 consists of a cathode 8, which is designed as a bed electrode. 250 g of nickel balls with a diameter of 2 mm are used as the electrode material, which were previously electroplated as described in Example 1 with a layer of nickel in which Raney nickel particles were embedded. The balls are in a ring-shaped, rotating fixed bed basket (mesh size 1 mm). The electrolyte is sucked in axially by the self-pumping action of the reactor and flows radially outwards through the fixed bed. Power is supplied to the inside of the electrode via sliding contacts.
  • the fixed bed basket has an outside diameter of 3.5 cm, an inside diameter of 2.5 cm and a height of 4 cm. It is operated at a speed of 1,800 rpm.
  • Anode 8 '(DeNora DSA) with an electrode area of 20 cm 2 is located in the anode space, which is spatially separated by a membrane 9 (Nation 324, DuPont). Serves as an anolyte 1.5% sulfuric acid.
  • indigo 1 g of indigo is dispersed in a solution of 490 ml of water, 5 ml of methanol and 5 ml of ethanol, which at the same time contains 10 g of sodium hydroxide solution.
  • the hydrogenation of the dye suspension is carried out at 55 ° C in the reactor after corresponding degassing with nitrogen (99%) by simply applying a cathode potential of -1000 mV vs. Ag / AgCI reached in 3 M KCI solution.
  • the working current is 1.2 A.
  • the catholyte flows through the reactor with a volume flow of 40 l / h. These conditions are maintained for 12 hours to fully hydrogenate dye A.
  • Example 8 also describes an electrocatalytic hydrogenation in a fixed bed reactor in batch operation.
  • the graphite-like electrode material used is activated by the application of platinum.
  • the reactor 7 consists of a cathode 8, which is designed as a bed electrode.
  • 40 g of the modified graphite granulate serve as the electrode material.
  • a centrally arranged platinum wire serves as the contact electrode.
  • the balls are located in a flow channel made of glass (cross section 7 cm 2 ) on a perforated glass plate.
  • Anode 8 '(DeNora DSA: electrode area 20 cm 2 ) is located in the anode space, which is spatially separated by a membrane 9 (Nation 324, DuPont).
  • Sodium hydroxide solution with a concentration of 40 g / l serves as the anolyte.
  • indigo 2 g of indigo are dispersed in 2000 ml of water, which also contains 80 g of sodium hydroxide solution.
  • the hydrogenation of the dye suspension is carried out in a simple manner at 50 ° C. in the reactor after corresponding degassing with nitrogen (99%) Applying a cathode potential of -1100 mV vs. Ag / AgCI reached in 3 M KCI solution.
  • the working current is 5.5 mA.
  • the catholyte flows vertically from bottom to top at 1.23 l / h. These conditions are maintained for 2.5 hours to fully hydrogenate dye A.
  • Example 9 describes an electrocatalytic hydrogenation in a flow-through reactor in filter press construction.
  • palladium on aluminum oxide built into a sponge-like glassy carbon structure is used as the electrode.
  • the RVC material commercially available in sheet form (100 ppi, reticulated vitreous carbon, ERG Materials and Aerospace Corporation, Oakland, USA) with the outer geometric dimensions of 10 x 10 x 0.5 cm is contacted by a copper wire and for 1 h with 1 I Phosphate buffer solution wetted (1 M potassium dihydrogen phosphate (KH 2 P0 4 ) and 1 M sodium hydroxide solution (NaOH), adjusted to pH 7). Then 7 g of Pd / Al 2 0 3 (5 w / o Pd) catalyst are added and the suspension is moderately stirred at 50 ° C. for about 2 h (450 rpm). During this time, the coal flow is polarized as a cathode with a constant current of 20 mA. Over time, the turbidity of the suspension disappears due to the incorporation of the metal particles into the carbon network.
  • the reactor 7 (Electro MP-Cell, Electrocell AB, Sweden) consists of two anodes 8 '(nickel sheet), which are located on both sides of the central cathode 8. This also consists of a nickel sheet on which a piece of RVC material with the outer geometric dimensions of 10 x 10 cm is attached on both sides. Catholyte and anolyte flow vertically through the respective electrode space from bottom to top with a volume flow of 1.2 l / min. A commercially available Nafion membrane 9 (Nation 324, DuPont) is used as the diaphragm.
  • indigo 20 g of indigo are dispersed in 2 l of water in the catholyte tank, which simultaneously contains 80 g of NaOH and 4 g of Setamol WS (BASF) as a dispersant.
  • 2 l of water, which contains 80 g of sodium hydroxide solution, are introduced on the anode side.
  • the hydrogenation of the dye suspension is carried out at 50 ° C. in the reactor after degassing Nitrogen (99%) by simply applying a cathode potential -1100 mV vs. Ag / AgCI reached in 3 M KCI solution. These conditions are maintained for 60 minutes to fully hydrogenate the dye.
  • Example 10 describes a further linkage in the fixed bed reactor in batch operation.
  • the reactor 7 consists of a cathode 8, which is designed as a bed electrode.
  • 40 g of graphite granulate material 00514, enViro-Cellmaschinetechnik GmbH, Oberursel, Germany
  • a centrally arranged platinum wire serves as the contact electrode.
  • the balls are located in a flow channel made of glass (cross section 7 cm 2 ) on a perforated glass plate.
  • Anode 8 '(DeNora DSA: electrode area 20 cm 2 ) is located in the anode space, which is spatially separated by a membrane 9 (Nation 324, DuPont).
  • Sodium hydroxide solution with a concentration of 40 g / l serves as the anolyte.
  • indigo is dispersed in 2000 ml of water, which also contains 80 g of sodium hydroxide solution.
  • the hydrogenation of the dye suspension is carried out at 50 ° C. in the reactor after corresponding degassing with nitrogen (99%) by simply applying a cathode potential of -1100 mV vs. Ag / AgCI reached in 3 M KCI solution.
  • the working current is 7 mA.
  • the catholyte flows vertically from bottom to top at 1.23 l / h. These conditions are maintained for 5 hours to fully hydrogenate dye A.
  • solubilizing agents and in particular the use of ultrasound, required for rapid coupling with high degrees of conversion leads to no pressure losses due to blockage of the electrodes, as a result of which backwashing by reversing the flow is eliminated.

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  • Engineering & Computer Science (AREA)
  • Textile Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrodes For Compound Or Non-Metal Manufacture (AREA)
  • Electrolytic Production Of Non-Metals, Compounds, Apparatuses Therefor (AREA)

Abstract

L'invention concerne un procédé pour l'hydrogénation électrocatalytique de colorants de cuve et de colorants au soufre dans des solutions aqueuses. Ce procédé peut être mis en oeuvre en mode discontinu comme en mode continu. Il ne fait intervenir aucun agent de réduction et autorise par conséquent, en raison de la quasi-absence de sels, des concentrations de colorants pouvant atteindre jusqu'à 200 g/l. Les fils colorés selon ce procédé se distinguent par une bonne résistance à l'abrasion et par un haut rendement au tissage. Ce procédé n'a pas d'effets nocifs sur les eaux résiduaires et réduit la charge en sels, ce qui permet de recycler les eaux résiduaires beaucoup plus facilement qu'avec les systèmes de teinture conventionnels. L'invention concerne également un appareillage pour la mise en oeuvre dudit procédé.
EP02782627A 2001-12-20 2002-12-20 Procede et appareillage pour l'hydrogenation electrocatalytique de colorants de cuve et de colorants au soufre Withdrawn EP1458924A1 (fr)

Applications Claiming Priority (5)

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CH23222001 2001-12-20
CH232201 2001-12-20
CH8012002 2002-05-13
CH801022002 2002-05-13
PCT/CH2002/000718 WO2003054286A1 (fr) 2001-12-20 2002-12-20 Procede et appareillage pour l'hydrogenation electrocatalytique de colorants de cuve et de colorants au soufre

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EP1458924A1 true EP1458924A1 (fr) 2004-09-22

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DE102004040601A1 (de) * 2004-08-21 2006-03-02 Dystar Textilfarben Gmbh & Co. Deutschland Kg Neuartige flüssige Chinonimin-Schwefelfarbstoff-Zusammensetzungen sowie Verfahren zu ihrer Herstellung und ihre Verwendung zum Färben von cellulosehaltigem Material
WO2008012231A2 (fr) * 2006-07-27 2008-01-31 Basf Se Utilisation de 1,5-diméthylpyrrolidone
CN113195791A (zh) * 2018-11-30 2021-07-30 赛杜工程股份有限公司 作为分散助剂的无色染料(例如靛白)
EP3887577B1 (fr) 2018-11-30 2022-12-07 Sedo Engineering SA Élimination de sous-produits (impuretés)
WO2020109595A1 (fr) * 2018-11-30 2020-06-04 Sedo Engineering Sa Réacteur électrochimique et son nettoyage ou régénération
CA3119492A1 (fr) 2018-12-14 2020-06-18 Redelec Technologie Sa Reacteur electrochimique
CN113227458B (zh) * 2018-12-14 2024-07-30 拉德伊莱克技术公司 电化学反应器
CN113120866B (zh) * 2021-03-31 2022-04-22 中南大学 一种利用二氧化硫制备单质硫的方法

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US1247927A (en) * 1914-09-25 1917-11-27 Andre Brochet Manufacture of leuco derivatives of vat dyestuffs.
FR2265901B1 (fr) * 1974-04-02 1977-10-14 Bombay Textile Res Assoc
JPS54112785A (en) * 1978-02-24 1979-09-03 Asahi Glass Co Ltd Electrode and manufacture thereof
US4584069A (en) * 1985-02-22 1986-04-22 Universite De Sherbrooke Electrode for catalytic electrohydrogenation of organic compounds
US5266731A (en) * 1991-07-17 1993-11-30 Reilly Industries Electrocatalytic hydrogenations of nitriles to amines
TW251325B (fr) * 1993-03-30 1995-07-11 Basf Ag
DE19513839A1 (de) * 1995-04-12 1996-10-17 Basf Ag Verfahren zur elektrochemischen Reduktion von Küpenfarbstoffen
AT408455B (de) * 1997-09-04 2001-12-27 Basf Ag Verfahren zur reduktion von schwefelfarbstoffen
DE59912528D1 (de) * 1998-11-24 2005-10-13 Walter Marte Verfahren und apparatur zur reduktion von küpen- und schwefelfarbstoffen
DE19962155A1 (de) * 1999-12-22 2001-06-28 Basf Ag Verfahren zur elektrochemischen Reduktion von Küpenfarbstoffen

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US20050121336A1 (en) 2005-06-09
AU2002347126A1 (en) 2003-07-09

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