DE2360792A1 - Highly pure organic pigments prepn - by forming suitable dyestuff salts (sulphates), recovering pure dyestuff and comminuting it - Google Patents

Abstract

Highly pure organic pigments are prepd. by treating organic dyestuffs having differing degrees of purity with suitable acids, which dissolve impurities in the dyestuffs, to form the corresp. dyestuff salts (pref. sulphates) which can be isolated; these salts are sepd. from the acids, and are treated with water so as to recover the dyestuff in pure form, and the dyestuff is then finely divided mechanically in aq., organic or aq. -organic medium. Organic dyestuffs such as highly halogenated (chlorinated) copper phthalocyanines, and dyes of the quinacridone, perylene tetra carboxylic acid, polycyclic quinone, dioxazine, indigo and thio indigo series and also acid-stable azo dyes, may be purified, but the process is esp. suitable for highly halogenated copper phthalocyanines. The procedure obviates the filtration of large volumes of greatly diluted acid (H2SO4) pigment suspension, and the working up of large volumes of dilute acid contg. impurities. The pigment are used for paper, plastics, resins, lacquers, textiles, paints, etc.

Description

»'ARB VV ERK E. HOEC II S Ϊ AG.
vermals '' Master Lucius & Brüning

File number: HOE 73 / F 373

Date; December 3, 1973

Process for the production of high-purity pigments

The subject of the application is a wastewater-friendly process for Production of high-purity pigments by treating raw color » substances with suitable, capable of forming salts with the dyes Acids that dissolve the impurities and then mechanical distribution of the pure paraffins to the pigment "

For converting a raw dye into an application technology Forms useful as a pigment are generally cleaning and a "so-called finishing process necessary. A combination of cleaning" For example, phthalocyanines have been providing treatment and finish for a long time known processes, the dye in short, sulfuric acid see below dissolve and then enter the solution in a large excess of water «

Processes are also known, according to which the raw dye in 60 - 90% sulfuric acid suspended and the suspension of the Dye sulfate formed by entering or spraying into finely divided an excess of water to release the original dye.

A disadvantage of this method, however, is that a large Part of the organic impurities, which are insoluble in dilute sulfuric acid, is precipitated again with the result that, although a Torture, but only limited purification of the dye is achieved.

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For this reason, processes have also been described where ν1οη «2ι ± one denotes Raw dye in conc. Sulfuric acid dissolves and then through Adding water only reduces the sulfuric acid concentrate to such an extent that the impurities remain dissolved in the acid, but at the same time the dye precipitates in the form of its sulfate and can be isolated. The fine distribution takes place then, such as B. in US Pat. No. 2,284,685, by redissolving the dye sulfate in conc. sulfuric acid and placing or spraying the solution in a large excess of water.

The decisive disadvantage of the previously known processes, however, is that the filtration of the large volumes of highly dilute sulfuric acid pigment suspension requires considerable technical and time expenditure and that large amounts of heavily contaminated and dilute sulfuric acid are produced, which are problematic to remove via the wastewater and to regenerate is expensive.

It has now been found that high-purity pigments with good properties can be produced inexpensively in terms of wastewater if one is acid-stable Raw dyes of different purity are converted into dye salts by means of suitable acids, these at a suitable acid concentration isolated, 'by decomposition of the dye salts with water The pure form of the dye is released again, filtered, with water Washes acid-free and then converted into the pigment form by mechanical fine distribution without pollution. Suitable acids are all acids which dissolve the impurities contained in the raw dyes and which can be used with them Coming dyes form isolable salts and economical technical processes exist for their regeneration.

Particularly suitable acids are for the claimed process _ z. B. sulfuric acid or oleum. But it can also z. B. highly concentrated Hydrohalic acids or halogenated acetic acids be used.

The claimed method is suitable in principle for all dyes that are against dilute and conc. Acids, especially against Sulfuric acid are stable and converted into isolable salts

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can be made from those with water the urti ^ rüilichero can be recovered. . '■' * ■

Suitable are see B «quinacridones, perylenetetracarboxylic acid dyes, polycyclic quinones, phthalocyanines, dioxazines, indigo and thioindigo dyes and acid-stable derivatives of the dyes mentioned, as well as acid-stable azo dyes. Really important are halogenated copper phthalocyanines, in particular highly halogenated copper phthalic cyanine.

From the strain of the quinacridones come especially those after the known ones Processes producible linear trans-quinacridones in question, which are unsubstituted or symmetrical or asymmetrical may be substituted, such as. B.

2 ', 9-dichloro-, 2,9-dimethoxy-, 2,9-dimethyl, 3,10-dimethyl, 3,10 ~ Di'chloT-, 3-methyl ~ 2-Chloi ¹ -, 4- -Chlor ~, 2,3-Mchlor-, 2-ChIOr-A-THe ^: / -! - or 2,9-Bichlor ~ 4,1 l-dimethyl-trans-quinacridone, 3,4,10, ii -Te'trachloro-quinacridone, 1,4,8,11-tetrachloroquinacridone or 2,4,9,1I-tetramethoxy-quinacridone.

Furthermore, trans-quinacridones with other than the acid-stable substituents mentioned are also suitable, as well as cis-quinacridones and angular quinacridones.

The term perylenetetracarboxylic acid dyes is used on the compound class of the general formula

IT-R

where R can be, for example, an alkyl, aryl, arylalkyl, alkoxy or a heterocyclic radical, which in turn can be substituted by various acid-stable groups.

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Furthermore, the perylene basic structure can also contain acid-acceptable substances, preferably halogen.

The polycyclic quinones include z. B. dyes with structures, by condensation of an ohinone residue with aromatic ones Remnants are obtained, such as. B. anthanurons, flavanthrones, Pyranthrones, Dibenzpyrenchinone, Anthraquinones with condensed aromatic residues, perinones and diperinones, violanthrones, isoviolanthrones and their acid-stable derivatives, preferably their halogenation products.

A dye sulfate is produced, for. B. by dissolving the dye in 96-100% sulfuric acid or in oleum and then diluting it with water or dilute sulfuric acid to an acid content at which the dye sulfate precipitates in a filterable form. The dye sulfate can, however, also be prepared by suspending the dye in sulfuric acid, the acid concentration being chosen so that it is sufficient for the complete conversion of the dye into the sulfate. This is generally the case in a sulfuric acid concentration range between $ 70 and $ 100.

The formation of the dye sulfate can usually be traced back to the training characteristically shaped crystals and their color, which usually deviates from the pure dye.

The amount of sulfuric acid is variable within wide limits, but it is expedient to use 4-20 times the amount based on the dye. Depending on the type of dye used, it can be advantageous to prepare the dye sulfate
to undertake.

Substance sulfate either at 20 - 30 ° or at a higher temperature

As soon as all of the dye has been converted into the isolable sulfate istj. this is isolated by filtration and washing with a small amount of 70 to 96% sulfuric acid of adherent Freed mother liquor. The isolated dye sulfate becomes the pure dye through the action of water in freedom set. To do this, the sulfate can either be washed acid-free directly with water or it can be stirred into water to isolate the

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- ς "

formed neutral particles and washes them acid-free.

The aqueous filter cake of the dye is then passed through mechanical fine distribution converted into pigment form »

For this purpose, all methods can be used that involve grain size reduction effect of dyes on pigment size, such as. B. the fine distribution in kneaders, with high-speed agitators Grinding action or in grinding units, the principle of which is based on the impact effect or mutual friction of grinding media due to rotation or vibration.

The fine distribution is preferably carried out on a roller mill, Vibrating mill or bead mill with the usual grinding media in practice and under the usual conditions,

Water, organic liquids and, above all, homogeneous mixtures of water and organic liquids can be used as grinding media. However, emulsions of water and organic liquids which are insoluble or only slightly soluble in water can also be used as grinding media. As organic liquids, for. B. alcohols, ketones, carboxylic acids, esters, ethers, hydrocarbons, halogenated hydrocarbons, amines and carboxamides in question «. Particularly favorable results are obtained when homogeneous mixtures of alcohols and water are used as the grinding medium. Preference is given to aqueous solutions of primary, secondary and tertiary aliphatic alcohols having 4 to 6 carbon atoms _f z. B. of isobutanol, tertiary butanol or cyclohexanol is used.

When using organic liquids as the grinding medium displaces the water adhering to the filter cake before the start of grinding and the fine division in the anhydrous medium using an organic liquid, e.g. B. isopropanol or xylene carried out.

The grinding can optionally be carried out with the addition of substances which facilitate the grinding and then evaporate without residue under the drying conditions of the ground material and allow it to be recovered through condensation, or which improve the properties of the ground pigment itself and therefore do not need to be removed. Such substances can, for. B. lcaticnen-active, anion-active 'or neutral interfacial

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be active substances in the usual amounts.

Following the grinding, the dye can be separated from the iv steel bodies in the usual way and dried. In In special cases, drying can be followed by an aftertreatment of the pigment paste by heating with water and / or with water miscible or immiscible liquids in suitable open or closed vessels.

The approx. 70-96 consecutive sulfuric acid obtained during the filtration of the dye sulphate is suitable for dye cleaning again, if necessary after concentrating to the original acid concentration and after replacing the sulfuric acid loss. The acid can therefore be used several times without regeneration. _ · _.

More heavily contaminated sulfuric acid, on the other hand, can because of its high Acid content can be cleaned economically according to the known regeneration process and then used again. as Regeneration processes are followed by the Pauling process, the thermal one Cleavage process or distillation in question.

The neutral washing of the dye sulfate in the Dilute sulfuric acid that forms when decomposed with water is completely free of inorganic and organic impurities and can therefore again lead to the precipitation of the dye sulfate from cons, Sulfuric acid used, or after-the immersion burner process on- concentrated and used again for dye cleaning.

The decisive advantage of the claimed process is therefore that the dye sulfate is produced and isolated the concentration of sulfuric acid is so high that "economical regeneration is possible" and therefore no ecological burden.

Another decisive advantage of the claimed process is that the decomposition of the dye sulfate accruing dye is obtained in a highly pure form and is extremely easy to finely distribute, so that it is already through the course Grinding can be converted into pigment form.

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Since the dye is in its purest form, subjected to grinding, v / ir & ^ ge long no impurities in the grinding medium due to the grinding process. The pigment is separated from the grinding medium in the usual way by filtration and provides, e.g. B. for the Pail that water was used as grinding medium, a waste water neutral Filtrate. If the grinding takes place in organic liquids, these can be repeated after filtration without regeneration can be used as grinding media. However, this makes the process particularly simple and inexpensive, that because of the high purity of the dye obtained, the expensive filtration after der.Mahlung completely dispense and can evaporate the grinding stock after separation from the grinding bodies directly in suitable drying apparatus.

The pigments produced by the claimed process are suitable for coloring paints, for coloring paper, plastics and synthetic resins, for coloring synthetic fibers in bulk, for Printing of paper and textiles and for metal effect coatings as well as for paints and inks,

The parts and percentages given in the examples are weight parts and "G-ev / icht percents. The temperature is in oelsius degrees specified. -:

BAD ORiGiNAL

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Example 1;

33 parts of raw copper phthalocyanine with a chlorine content of $ 48 are divided into 500 parts icons. Entered sulfuric acid and ^{stirred at 25-3O 0} C for 8 hours. Then one drips "at 70 - 8O ⁰ C 65 parts of water and sucks the crystal mass of the copper · - sulfata from an acid-resistant filter is washed with 160 parts of 80 ^ strength sulfuric acid and stirring the filter cake then at 25 -. 30 ° in 330 parts of water, filtered off with suction and washed acid-free with water. Yield: 93 parts of aqueous filter cake with a solids content of $ 35 ·

The filter cake produced in this way is made up of 117 parts share

Water and. 120ÖYu> uarzbeads. of approx. 2 mm 0 in a porcelain mill for 15 hours. Ground on a vibrating table. The mixture is then separated, filtered and dried in vacuo at 6O ⁰ C and the grinding media. Yield * 31 »3 parts pigment. With the pigment produced in this way, stoving enamels can be colored by known methods in brilliant, deeply colored green tones of high transparency. "

Example 2: ^;

33 parts of copper phthalocyanine nit a chlorine content of 48 # are the unter.Verwendung obtained in the purification of Example 1, about 85 follow Schwefelsäurefiltrats by the procedure of Example 1 to give the Schwefelsäurekonzentrati on the verwendetet filtrate beforehand by adding oleum to 96 - 100 tfo sulfuric acid is strengthened.

The more heavily contaminated sulfuric acid that occurs after the filtrate has been used several times is regenerated by distillation.

Example 3 «

V.

50 parts of 80 $ iges crude copper phthalocyanine (chlorine content of the copper phthalocyanine 48 - 49 f °) are concentrated in 400 parts. Sulfuric acid and, after adding a small amount of sodium nitrite, stirred at 25 - 30 ° - until the conversion into the

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! Dye sulfate is complete. Then "52 parts of Yfes'ser" are added dropwise at 70-80 ° and the crystalline mass of the copper phthylcyanine sulfate is filtered off with suction at room temperature through an acid-resistant filter. It is washed with about 200 parts of 80% sulfuric acid and stirred the filter cake then at 25 - 30 ⁰ G -in 400 parts of water, filtered off and washed with water until acid free. Yield: 98 parts of aqueous filter cake with a pesticide content of 40% .

The filter cake thus prepared is, together with 1.31 parts Y / ater, 15 parts Isohutanol and 1300 parts of quartzite beads of about 1 mm 0 in a porcelain mill for 15 hours on a vibration, ground table. It is then separated from the grinding media and the mixture is evaporated to dryness at 60 ° in vacuo. Yield: 39 parts of pigment.

With the pigment produced in this way, stoving enamels can be produced in brilliant green tones of high transparency according to the "known methods" stain. "· '·' Draw the PYC colors obtained by known methods are characterized by high color strength and purity of the color shade. Is used in the aqueous-organic grinding medium instead of 15 parts of isobutanol, 15 parts of tertiary butanol or 15 parts tertiary amyl alcohol or 7 parts of cyclohexanol, pigments are obtained comparable quality.

example

28 parts of 90 series "perchlorinated Boh copper phthalocyanine (chlorine content of the copper phthalocyanine 48 - 49 ° C) are added to 250 parts of 100 " series sulfuric acid and stirred in a nitrogen atmosphere after adding a small amount of mtrosylsulfuric acid for several hours at .70 - 80 °, until the transfer to the coloring. sulfate is complete * Then 44 parts Y / ater are added dropwise at 70 - 80 °. After cooling to 20-30 °, the sulfate dye is acid-resistant. Filter suction filtered and washed with 80 parts of 80% sulfuric acid. The filter cake is then washed neutral with water.

62 parts of a 40.3 follow aqueous filter cake are obtained perchlorinated pure copper phthalocyanine, corresponding to 25 parts Pure dye.

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' ^J

The filter cake thus prepared is exhale with Bf parts of acetone and 1200 parts of quartzite pearls of 2 mm in a Porzellannröhle 0 for 20 hours at a vibratome-vibration table milled. The dye suspension is then separated from the grinding media and evaporated to dryness in vacuo at 60 °.

The dye produced in this way gives brilliant, strongly colored green tones when stoving enamels are colored. The pigment Compared to the "known commercial products, it is also characterized by a significantly improved dispersibility in paint systems.

A pigment of comparable quality is obtained if the dye suspension is not made by vibratory grinding but finely divided by continuous bead milling and then continuously evaporated to dryness at normal pressure.

Used instead of perchlorinated copper phthalocyanine Hexadecabromo-copper phthalocyanine, then one obtains a pigment dyestuff ", which, when coloring stoving enamels, produces yellowish, deeply colored green tones.

Example 5 «,

25 parts of perchlorinated copper phthalocyanine (in the form of the 62 parts of a 40.3 / fig aqueous filter cake described in Example 4) are introduced into 150 parts of technical-grade xylene mixture. The water is then removed by circling. The water-free dye suspension is ground with 1200 parts of quartzite pearls of 2 mm 0 in a porcelain mill for 20 hours on a vibrating table. The dye suspension is then separated from the grinding media. The suspension is stirred in an autoclave at 150-160 for 3 hours. After cooling to below 100, the dye is suctioned off and dried at 100 ° in a vacuum «

The pigment produced in this way provides when staining Stoving enamels brilliant, strong green tones. The colorations

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are more opaque than those using the after. Example 1 o-lsr 4 obtained pigment. The Dispergierbarkoii in Lacquer systems is excellent.

Draw the PVC colors obtained by "known methods" are characterized by high color strength and purity of the color tone.

Example 6;

35 parts IT, IT ^f -dirnethylperylen-3 »4 * 9 * 10-tetracarboxylic acid diimide (95%) v / earth in 350 parts conc. "Solved sulfuric acid is then added dropwise to water at 50" 6.0 ⁰ O..67 parts, filtering the precipitated dye-sulfate through an acid-resistant filter and washed with 160 parts of 80 $ strength sulfuric acid.

Stirring is then the filter cake in 330 parts water eir> _y filtered off and washed with water until acid free. , 8t parts of an aqueous filter cake is obtained ca 40 "$ solids content. The filter cake thus obtained is mixed with 129 parts of water and 1200 parts of quartz beads of approximately 2 mm 0 milled 15 ^Ί in a porcelain mill on a rocking table. After separation -veη the grinding media is filtered and dried "in vacuo at 6O ⁰ O with the pigment thus produced can stoving lacquers according to known methods in clear! strong color shades of red dye.

Example 7 ?

30 parts of 2,9-dimethyl-trans-china.cridone are dissolved in 600 parts of concentrated sulfuric acid. To the resulting blue solution is added dropwise at 50 - 7O ⁰ C, 150 parts of water are added, the needle crystals formed are filtered off on an acid-resistant filter and washed with 200 parts of 80 ^ strength sulfuric acid. The filter cake is poured into 300 parts of water, the released dye is filtered and washed acid-free with water. 69 parts of an aqueous filter cake with a solids content of 40 ° are obtained.

The filter cake is milled with 158 parts of water and 1200 parts of quartz beads of approximately 2 mm 0 8 hours in a porcelain mill on the vibrating table and evaporated after separation of the grinding media to dryness.
The pigment produced in this way colors stoving enamels in pure red

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Tones of high brilliance; and part »strength,

Example 8 :

30 parts of raw flavanthrone are concentrated in 300 parts. Dissolved sulfuric acid. Then drops at 50 to 36 parts water to 70 ⁰ O that flavanthrone sulfate crystals formed drawn in through · an acid-resistant filter at room temperature and washed with 150 parts of 80 $ strength sulfuric acid. The filter cake is stirred into 300 parts of water, the dye is filtered off and washed acid-free with water. This gives 63 parts of an aqueous filter cake with 43 $> solids content. · The filter cake is ground with 174 parts of water and 1,200 ropes quartz beads of approximately 2 mm 0 15 hours in a Poraellanmühle on a vibrating table. The grinding paste separated from the grinding media is then filtered and dried in vacuo at 60 °.

The stoving enamels colored with the pigment obtained in this way are distinguished by a pure yellow hue and high color strength the end.

Example 9s

30 parts of crude 4,10-dibromoanthanthrone are used in 750 parts of kona. Dissolved sulfuric acid. 90 parts of water are then added dropwise at 50-70 ° C., the dye sulfate formed is filtered off through an acid-resistant filter and washed with 300 parts of 80 subsequent sulfuric acid. The filter cake is stirred into 300 parts of water, and the dye formed is filtered off and washed acid-free with water. This gives 117 parts of an aqueous filter cake with 23 i "solids content"

The filter cake is ground with 120 parts of water and 1200 parts of quartz beads of approximately 2 mm 0 15 Stund.en in a porcelain mill on the vibrating table and after separation from the milling bodies ~ evaporated to dryness.

The pigment produced in this way colors stoving enamels in pure orange tones of high color strength «

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Claims (13)

Expectations . 1. A process for the production of high-purity organic pigments, characterized in that organic dyes of different degrees of purity are converted into isolable dye salts by means of suitable acids which dissolve the impurities contained in the dye, and these are separated from the acid from the dye salts by the action of water
the dyes are recovered in pure form and the isolated dye is subjected to mechanical fine division in an aqueous, organic or aqueous-organic medium. 2. The method according to claim 1, characterized in that the
Dye salts which can be isolated represent dye sulfates. ■ 3. The method according to claim 1 and 2, characterized in that the dye sulfate by reaction, the dye with
70 to 100% sulfuric acid and then
optionally the acid by adding water to a
Concentration at which the dye sulfate can be isolated. 4. The method according to claim 1 to 3, characterized in that the organic dye is a highly halogenated copper phthalocyanine is. · 5. The method according to claim 1 to 4 »characterized in that the organic dye is a highly chlorinated copper ph.thaloc.y ~ anin is, 6 «Method according to claim 1 to 3> characterized in that the organic dye is a polycyelic ohinone. 7. The method according to claim 1 to 3, characterized in that the organic dye belongs to the perylerite tetracarboxylic acid series. BATH ORIGINAL 509824/07 64 8. The method according to claim 1 "to 3» characterized in that the organic dye belongs to the ghinacridone series. 9. The method according to claim 1 "to 8, characterized in that mechanical fine distribution takes place in a vibrating mill, roller mill or bead mill. 10. The method according to claim 1 "to 9» characterized in that mixtures of water and alcohols are used as the aqueous-organic grinding medium. 11. The method according to claim 1 to 10, characterized in that the aqueous-organic grinding medium used is homogeneous mixtures of water and primary, secondary and tertiary aliphatic alcohols having A to 6 carbon atoms. 12. The method according to claim 1 to 11, characterized in that the grist is dried without filtration. * 13. The method according to claim 1 to 8, characterized in that one obtained in the isolation of the dye sulfate Sulfuric acid used several times for the cleaning process without regeneration. 14c The prepared by the method according to claims 1 to 13 Pigment dyes. Use of the pigments produced according to claims 1 to 13 for coloring paper, plastics, synthetic resins and synthetic fibers in bulk, for coloring paints, for printing paper and textiles, for paints and for inks, as well as for metal effect finishes. 509824/0764