Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D231/00—Heterocyclic compounds containing 1,2-diazole or hydrogenated 1,2-diazole rings
  • C07D231/02—Heterocyclic compounds containing 1,2-diazole or hydrogenated 1,2-diazole rings not condensed with other rings
  • C07D231/10—Heterocyclic compounds containing 1,2-diazole or hydrogenated 1,2-diazole rings not condensed with other rings having two or three double bonds between ring members or between ring members and non-ring members
  • C07D231/14—Heterocyclic compounds containing 1,2-diazole or hydrogenated 1,2-diazole rings not condensed with other rings having two or three double bonds between ring members or between ring members and non-ring members with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached to ring carbon atoms
  • C07D231/44—Oxygen and nitrogen or sulfur and nitrogen atoms
  • C07D231/52—Oxygen atom in position 3 and nitrogen atom in position 5, or vice versa
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03C—PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES; PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY
  • G03C7/00—Multicolour photographic processes or agents therefor; Regeneration of such processing agents; Photosensitive materials for multicolour processes
  • G03C7/30—Colour processes using colour-coupling substances; Materials therefor; Preparing or processing such materials
  • G03C7/32—Colour coupling substances

Definitions

• Dye-forming coupler recovered from photographic color developer solution is purified by contacting the impure coupler in admixture with water with an organic solvent comprising an acylating agent so that the acylating agent reacts with the water to generate heat and bring about solution of the coupler and the impurities, whereupon the coupler is recovered in purified form by recrystallization from the solution.
• the acylating agent also acts to convert to coupler any amine derivative formed by alkaline hydrolysis of the acylamido group in the developer solution.
• This invention relates to color photography and more particularly to photographic color developer solutions and a novel method for recovering color forming coupler in pure form from used and/or exhausted color developer solutions.
• Color developing solutions are used in the processing of exposed photographic elements for color photography in order to produce the dye images that form the color picture in the processed element.
• the final picture is usually made by the formation of a cyan dye image, a yellow dye image and a magenta dye image in superposed relationship.
• the cyan dye image development is accomplished with an alkaline developer solution which contains a color developer and a cyan-forming coupler which is usually a phenolic or naphtholic type coupler.
• color developer is oxidized to a compound that couples with the cyan-forming coupler present to form a nondilfusing dye image.
• the yellow dye image development is accomplished with an alkaline developer solution containing a color developer and a yellow dye-forming coupler.
• the magenta dye image is developed with an alkaline developer containing a color developer and a magenta dye-forming coupler.
• acylacetamide type couplers are used in yellow dyeforming developers and a Z-pyrazolin-S-one or a coumarone type coupler is used in the magenta dye-forming developer.
• Each of these color-forming couplers have a reactive hydrogen on a methylene group that is adjacent to a keto group, or a reactive hydrogen atom on a methine group that is ortho to or para to a hydroxy group on an aromatic ring.
• the alkaline developer solution usually contains other constituents such as potassium bromide, sodium sulfite, sodium carbonate, and other materials in order to give a developed image having the desired sensitometric characteristics (that is, relationship between exposure and resulting image density).
• a batch process may be used in which developer solutions are used untilexhausted, then replaced with fresh developer for another batch of film.
• the exhausted or used developer solution still contains substantial concentrations of the color-forming coupler. Because of the relatively high cost of the coupler compounds, it is advantageous to recover them for reuse in fresh developer solution.
• One object of our invention is to provide a novel process for easily and efficiently purifying acid dye-forming couplers recovered from spent (used and/or exhausted) aqueous alkaline color developer solutions so that the purified recovered coupler is photographically indistinguishable from freshly synthesized coupler.
• Another object of our invention is to provide a novel process for contacting impure coupler recovered from spent aqueous alkaline color developer solutions with an brganic solvent comprising an acylating agent so that sufiicient heat is produced to dissolve the impurities and a substantial amount of the coupler, as Well as acylating any of the amine derivative of the said coupler which may have been further produced by alkaline hydrolysis of the acylamido groupon the said coupler, followed by recrystallization of the coupler and removal of substantially all of the dissolved impurities leaving pure coupler.
• Another object of our invention is to provide a novel process in which the deacylated coupler in impure recovered coupler is reconverted to the coupler and the necessary heat for recrystallization is simultaneously supplied, by contacting the impure coupler in the presence of water with an acylating agent, thus reforming coupler from an inert impurity which would otherwise be lost and eliminating the need for expensive equipment for supplying heat needed for recrystallization from external sources.
• Still another object of our invention is to provide a novel process for repurifying dried impure coupler recovered by prior art methods so that the unsatisfactory coupler can be purified sufficiently so that it can be used in place of freshly synthesized coupler.
• Our process is used advantageously to easily and effectively convert impure coupler recovered from spent color developer solutions by acidification methods so that the purified coupler is substantially free from both inactive and photographically active impurities and can be used weight by Weight in place of freshly synthesized coupler, producing uniformly high-quality photographic results.
• a very important feature of our method is the reformation of coupler from the amine derivative of the coupler (formed by alkaline hydrolysis of the acylamido group on couplers in used color developer solutions).
• the reformation of the coupler from the photographically inactive amine derivative makes available for recovery from approximately 3 to 10% of additional coupler which would otherwise be lost and could even be a very unwanted diluent in the recovered coupler material. This additional amount of coupler provides a saving which may pay for the cost of recovering the coupler.
• Our process provides a method in which a high concentration of organic solvent is obtained in the wet impure coupler precipitate with a relatively small volume of organic solvent. Since the acylating agent reacts exothermically with water present, all of the heat necessary for recrystallization is supplied by this reaction. This eliminates the need for an external source of heat as well as expensive heat exchanging equipment which would otherwise be necessary. The maximum temperature of the reaction is easily controlled by the choice of the ratio of damp coupler and the organic solvent used.
• our process is used to advantage in purifying any aqueous alkali-soluble acid color-forming coupler used in color developer solutions for photographic color processing provided that the coupler is free of substituents (e.g., amino, alkylamino, hydroxyalkylamino, etc.), that react with acylating agents, and preferably couplers that have an acylamido group substituent e.g., acetamido, propionamido, butyrylamido, etc.
• substituents e.g., amino, alkylamino, hydroxyalkylamino, etc.
• couplers that have an acylamido group substituent e.g., acetamido, propionamido, butyrylamido, etc.
• acid color-forming coupler is precipitated from the aqueous alkaline color developer solution by acidifying the solution with a mineral acid or preferably by bubbling carbon dioxide gas throughout the solution as described in Anselm, US. Patent 3,201,412, issued Aug. 17, 1965.
• the solution is then removed from precipitated coupler by any suitable means, such as by filtration, centrifuging, etc.
• the Wet coupler in the filter cake from the filtration or centrifuging contains in the range from about 25 to about 75% water by weight.
• the filter cake was dried.
• the wet impure recovered coupler (filter cake) containing at least about 25% water is contacted with an organic solvent comprising an acylating agent with or without an organic acid, e.g., acetic acid, pro pionic acid, butyric acid, etc.
• an organic solvent comprising an acylating agent with or without an organic acid, e.g., acetic acid, pro pionic acid, butyric acid, etc.
• a vent pipe adjacent to the top of the tank with sufficient air flow is used to advantage to remove solvent fumes.
• the dry material is moistened by adding about 200% by weight of water before treating with the organic solvent(s).
• the acylating agents used to advantage according to our invention include organic acid anhydrides, e.g., acetic anhydride, propionic anhydride, butyric anhydride, etc., organic acid halides, e.g., acetyl chloride, propionyl chloride, butyryl chloride, acetyl bromide, propionyl bromide, etc.
• the acylating agent used is chosen so that the desired acylamido group will be reformed on the amine derivative of the coupler.
• the organic acid anhydrides are usually the preferred acylating agents in our process.
• the amount of acylating agent used may be varied considerably and will depend upon the amount of water in the damp impure recovered coupler being treated, the amount of amine to be reconverted to coupler, the maximum temperature desired in the reacting mixture, etc.
• the mole ratio of acylating agent to water in the damp impure recovered coupler can advantageously be in the range from about 1:1 to about 1:8 with a range of from about 1:3 to about 1:4 being preferred. We have found a mole ratio of 1:4 to be excellent. In the preferred ratios there is a large excess of water so the amount of acylating agent used determines the amount of heat produced and the maximum amount of temperature rise.
• the temperatures used to advantage are in the range of from about F. to about 260 F., preferably in the range from about 180 F. to about 220 F.
• the minimum total solvent that is used advantageously is that which produces a slurry of coupler in the solvent that is thin enough to be stirred. This will depend upon the characteristics of the particular coupler involved.
• solvents such as acetic acid, propionic acid, etc. are used to advantage to give the desired volume.
• the reaction mixture After completion of the reaction of acylating agent with the amine derivative of the coupler and water, the reaction mixture is allowed to cool to room temperature or sufliciently to cause recrystallization of the coupler which dissolved during the reaction step when heat was involved.
• water it is not necessary to add water to the cooling reaction mixtures, it is advantageous to add water having a volume of from about one-half to about 10 times the volume of the organic solvents, any time after the maximum temperature has been reached. The addition of water gives a thinner slurry and will aid in recrystallization of the dissolved coupler.
• solvent is removed by suitable means e.g., filtration, centrifuging,
• the filter cake dried or water Washed, filtered (or centrifuged) and then dried.
• the dried coupler is sufficiently pure for use in making color developer solutions without blending it with freshly synthesized coupler.
• Example 1 Cyan color developer collected from the overflow of the cyan color developer tank in a color processing machine was acidified to precipitate the couple 2-(0- acetamido-fi-phenylethyl) 1 hydroxynaphthamide. The slurry was centrifuged to remove the solution leaving recovered damp coupler containing about 70% by weight water. Six kg. of this damp coupler was placed in a tank and stirred while a mixture of 5 liters of acetic anhydride and 4 liters of acetic acid were added. A maximum temtemperature of 196 F. was obtained in about 50 minutes. When the temperature receded to about 180 F., 6 liters of water were added, stirred and the mixture was allowed to cool to room temperature.
• the cooled mixture was filtered through filter paper and the coupler filter cake was washed twice with about 5 liters of water each time.
• the damp coupler was spread in glass trays and dried by a combination of hood-drying for 5 days and oven-drying at 212 F. for 32 hours. Based on the dry weight of 400 grams of the same damp coupler used for purification, a 94% yield was obtained.
• Example 2 Six kg. of the recovered damp coupler containing about 70% by weight water obtained by centrifuging acidified cyan developer solution was stirred in a tank while 5 liters of acetic anhydride and 2 liters of acetic acid were added. The slurry was too thick to stir well and another liter of acetic acid was added. A maximum temperature of 210 F. was attained. When the temperature dropped to 205 F., 6 liters of water were added, stirred, and the mixture allowed to cool at room temperature. Some of the batch was collected in a small centrifuge, washed with hot water and dried at 212 F. The rest of the batch was filtered, washed and dried as in Example 1.
• Example 3 Example 2 was repeated excepting that the 3 liters of acetic acid were all added with the acetic anhydride. A maximum temperature of 200 F. was obtained with stirring being continued until the temperature receded to 150 F., then 5 liters of water were added, stirred 10 minutes and the mixture allowed to cool to room temperature. The cooled material was filtered, washed, and dried as in Example 1. An 88% yield was obtained. Four photographic tests showed that although starting material was unacceptable, the purified material was indistinguishable from fresh coupler.
• Example 4 Similar results are obtained when Example 1 is repeated in which a cyan developer containing the cyan coupler 5-propionylamide-Z-phenyl carbamylphenol is used in place of the color developer solution of Example 1. In this process propionyl chloride is used in place of acetic anhydride.
• Example 5 Similar results are obtained when Example 1 is repeated in which a magenta color developer solution containing the magenta coupler l-(p-acetamidophenyl)-3- anilino-2-pyrazolin-5-one is used in place of the cyan color developer in Example 1.
• Our process is used to advantage in purifying any aqueous alkali-soluble, acid, color-forming coupler used in color developer solutions for photographic color processing providing that the coupler is free of substituents, e.g., amino, alkamino, hydroxyalkyl, etc. that react with acylating agents and preferably couplers that have an acylamido group substituent.
• Our process produces a coupler which is photographically indistinguishable from freshly synthesized couplers when used in making color developer solutions.
• the reaction used not only reforms coupler from photographically inert coupler derivatives formed by alkaline hydrolysis of the coupler in spent color developer solutions, but furnishes all of the heat required for recrystallization of the coupler. All of these advantages provide a substantial technical advance through the use of our process.
• a process for purifying impure acid dye-forming coupler that has been recovered from aqueous alkaline photographic color-forming developer solution by precipitation with a mineral acid or carbon dioxide, said coupler bearing an alkanoylamido group substituent and being free of substituents that react with acylating agents and said impure coupler containing as one impurity the amine derivative of said coupler, said amine derivative having been formed in said color developer solution as a result of alkaline hydrolysis of said alkanoylamido group; said process comprising the steps of (l) contacting a mixture comprising said impure coupler and water wherein the water is at least about 25 percent by weight of said mixture with an organic solvent comprising a sufficient amount of an acylating agent, selected from the group consisting of the anhydride and the halide of the alkanoic acid corresponding to the alkanoyl radical of said alkanoylamido group, to convert said amine derivative to said coupler and to react with the water present to elevate the temperature of the mixture formed
• step (1) recrystallizing said dissolved coupler in the mixture from step (1) by cooling or by diluting with water in an amount equal to from about one-half to about ten times the volume of organic solvent utilized in step (1) to thereby leave the impurities in solution, and
• step (3) extracting from the mixture from step (2) substantially all of the solution containing the impurities to thereby leave wet purified coupler which, when dried, can be used in place of newly synthesized coupler in color developer solutions.
• a process for recovering aqueous-alkali-soluble acid dye-forming coupler from a photographic color-forming developer solution said coupler bearing an alkanoylamido group substituent and being free of substituents that react with acylating agents and said developer solution comprising water, an alkali, a primary aromatic amino color developing agent, a water-soluble alkali metal salt of said coupler, and a water-soluble alakli metal salt of the amine derivative formed by alkaline hydrolysis of the alkanoylamido group on said coupler; said process comprising the steps of:
• step (3) recrystallizing said dissolved coupler in the mixture from step (3) by cooling or by diluting with water in an amount equal to from about one-half to about ten times the volume of organic solvent utilized in step (3) to thereby leave the impurities in solution, and

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• 1966
  • 1966-02-21 US US528767A patent/US3458574A/en not_active Expired - Lifetime
• 1967
  • 1967-01-09 GB GB1083/67A patent/GB1139152A/en not_active Expired
  • 1967-02-09 BE BE693878D patent/BE693878A/xx unknown
  • 1967-02-16 FR FR95122A patent/FR1511490A/fr not_active Expired
  • 1967-02-20 DE DE19671547776 patent/DE1547776A1/de active Pending

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