DE2941385A1 - DISPERSIONS OF NITROANTHRACHINONES, METHOD FOR THE PRODUCTION THEREOF AND THEIR USE - Google Patents

Description

BAYER AKTIENGESELLSCHAFT 5090 Leverkusen-Bayerwerk

B / bc / c

Oct 11, 1979

Central area B / bc / c

Patents, trademarks and licenses

Dispersions of nitroanthraquinones, process for their preparation and their use.

Nitroanthraquinones have a beneficial effect in certain processes for the extraction and bleaching of Pulp made from lignocellulosic materials such as wood, straw and bagasse when in amounts of 0.001 up to 10% by weight, based on the dry weight of the lignocellulosic material, can be used.

The nitroanthraquinones are generally in the form of powders. The use of such powdery Nitroanthraquinones in processes for the production of cellulose from lignocellulosic materials and however, their bleaching causes difficulties. If you put the powdery nitroanthraquinones lignocellulosic material to be digested directly to, the finer proportions of nitroanthraquinones easily get into the environment in the form of dust.

That way they are not just def intended Use withdrawn, but also lead to nuisance to those working in the vicinity of the feed point Humans and can even cause dust explosions. It is also because of the relatively low Amounts of the required nitroanthraquinones an equal

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moderate distribution difficult. A uniform distribution of the nitroanthraquinones is, however, to be achieved a uniform pulp quality is essential.

A uniform distribution of the nitroanthraquinones is also made more difficult by the fact that the nitroanthraquinones in water and in the aqueous digestion solutions used in pulp production in general are not only very sparingly soluble, but are also poorly wetted. Leave as a result of poor wetting the finer proportions of the powdery nitroanthraquinones do not stir in or only poorly and instead float unwetted, if necessary with the inclusion of air, on the surface.

¹ S Since the nitroanthraquinones a relatively high specific gravity have (for example, has 2.7-dinitroanthraquinone at 2O ⁰ C, a specific gravity of 1.558 g / cm) set, the coarser fractions of the powdery nitroanthraquinones, when stirred into water or into the digestion solution, rapidly and after standing briefly on the bottom of the vessel they form a compact layer that can only be swirled up again with difficulty. The addition of the nitroanthraquinones directly to the cooking liquor, in the mixture of lignocellulose materials and cooking liquor or in the form of a suspension in water is therefore not a way of achieving the required uniform distribution of the nitroanthraquinones.

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It has now been found that the difficulties described above when using the nitroanthraquinones can be avoided if the nitroanthraquinones are used in the form of certain dispersions. These dispersions are obtained by dispersing the nitroanthraquinones, not in conventional diapering agents, for example water, but rather in dispersing agents which have the same or a similar density as the _{nitroanthraquinones to be} dispersed.

The invention therefore relates to dispersions of nitroanthraquinones in liquid dispersants which have the same or a similar density as the nitroanthraquinones.

In the context of the invention, the term “pulp production” is understood to mean all processes and process stages in which lignin is converted into lignin and cellulosic materials are chemically acted upon. Examples are alkaline, neutral and acidic digestion processes for lignocellulose materials such as wood, straw, bagasse and grasses, as well as bleaching processes for partially or largely digested lignocellulosic materials

Representatives of the nitroanthraquinones to be dispersed according to the invention are, for example, mono- or Dinitroanthraquinones called, which optionally in addition to the nitro groups one or more may have further substituents. As another

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Substituents come, for example, alkyl, alkoxy, Halogen, amino, hydroxy, carboxy and / or sulfo groups and / or fused iso- or heterocyclic rings in question. Preferred as further substituents are alkyl and alkoxy groups each with 1 to 4 carbon atoms, as well as chloro and / or sulfo groups. the The number of further substituents can be, for example, 1 to 6, preferably 1 to 4. as Examples of such mono- and dinitroanthraquinones are: 1- and 2-nitroanthraquinone, 1.5-, 1.6-, 1.7-, 1.8-, 2.6- and 2.7-dinitroanthraquinone; i-Nitro-5, 1-Nitro-6, 1-Nitro-8, 2-nitro-i-chloro-anthraquinone, 2-nitro-4,5-dichloro-anthraquinone; 2. nitro-1,4-, 1-nitro-5.8-diamino-anthraquinone; 1-nitro-4-amino-anthraquinone; 1,3-dinitro-4-amino-anthraquinone; 1-nitro-4-hydroxyanthraquinone, 1-nitro-3.4-, 1-nitro-5.8-, 1.5-dinitro-4.8-dihydroxy-anthraquinone; 1,5-dinitro-4,8-dihydroxy-anthraquinone, 1,8-dinitro-4,5-dihydroxy-anthraquinone; 2-nitro-3.4.7-trihydroxyanthraquinone; 1-nitro-4-ethoxy-anthraquinone; 1-nitro-2-, 2-nitro-3-carboxy-anthraquinone; 1-nitro-3-carboxy-4-amino-anthraquinone; 4.4'-dinitro-1.1-diantrimide; i-nitro-4-, 2-nitro-1-methyl-anthraquinone; 1-nitro-4-bromo-anthraquinone and i-nitro-5-ethoxy-anthraquinone.

In the context of the present invention, nitroanthraquinones also include those which are partially hydrogenated in the nucleus To understand derivatives of nitroanthraquinones and / or their tautomeric forms.

The dispersions according to the invention preferably contain 1- and 2-nitroanthraquinone, 1-nitro-5-chloro

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anthraquinone, i-nitro-4-amino-anthraquinone, 1-nitro-4-hydroxy-anthraquinone, 1-nitro-2-carboyxy-anthraquinone, i-nitro-5-ethoxy-anthraquinone and / or 2-methyl-1-nitroanthraquinone and in particular 1.5-, 1.6-, 1.7-, 1.8-, 2.6- and 2.7-dinitroanthraquinone.

The dispersions according to the invention particularly preferably contain mixtures of unsubstituted mono- and / or dinitroanthraquinones. Such mixtures occur, for example, in technical nitration of anthraquinone and / or mononitroanthraquinones. In particular, the dispersions according to the invention can Contain mixtures of mono- and / or dinitroanthraquinones that arise when using anthraquinone on an industrial scale mono- or dinitrated or mononitroanthrachinongemisehe nitrated and from the resulting nitration products the isomers valuable as dye intermediates, e.g. 1-nitro-, 1.5-dinitro- and / or 1.8-dinitroanthraquinone separates. The latter mixtures contain 1.5-, 1.6-, 1.7-, 1.8, 2.6 and 2.7 dinitroanthraquinone. Contain particularly preferred mixtures as nitroanthraquinones for example 0 to 3% by weight 1-nitroanthraquinone, 5 to 12% by weight 1,5-dinitroanthraquinone, 15 to 35% by weight 1,6-dinitroanthraquinone, 15 to % By weight of 1,7-dinitroanthraquinone, 15 to 50% by weight of 1,8-dinitroanthraquinone, 0.5 to 3% by weight of 2,6-dinitroanthraquinone and 0.5 to 3 wt% 2,7-dinitroanthraquinone.

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The nitroanthraquinone content of the dispersions according to the invention can be from 5 to 80 wt .-%, preferably 20 to 70 wt .-%, based on the weight of the Dispersions.

As liquid dispersants to be used according to the invention liquids are suitable which have the same or a similar density as the nitroanthraquinones to be dispersed, i.e. liquids whose density ranges from 1.2 to 1.85 g / ml, preferably 1.4 to 1.65 g / ml. With these liquids suitable as dispersants it can be pure compounds as well as solutions and dispersions.

Dispersants according to the invention include, for example, electrolyte solutions such as aqueous solutions of metal oxides, hydroxides and / or salts and / or acids and / or aqueous solutions of nitrogen bases and / or of salts of nitrogen bases, e.g. the aqueous solutions of oxides, hydroxides, sulfides, sulfites, bisulfites, sulfates, thiosulfates, carbonates, Chlorides, bromides, iodides, nitrates and nitrites of sodium, potassium, ammonium, calcium and / or magnesium and / or sulfuric acid and / or phosphoric acid.

Preferred solutions are the aqueous solutions of sodium hydroxide, sodium sulfide, sodium sulfite, sodium bisulf it, sodium sulfate, sodium thiosulfate, sodium nitrite, sodium nitrate, potassium sulfide, magnesium bisulf it, calcium bisulfite and / or ammonium sulfite.

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Aqueous sodium hydroxide solution and, above all, aqueous potassium carbonate solution and sulfuric acid have proven particularly useful .

It has been found to be advantageous to use such aqueous electrolyte solutions as are used or obtained in any case in the various stages of cellulose production. The density of the electrolyte solutions obtained in the process, such as the so-called white liquors, cooking liquors , screed liquors, thick liquors and / or green liquors, can optionally be adjusted to the required values by concentration, for example evaporation of water, or by adding additional amounts of electrolyte.

The named alkalis are understood to mean the following solutions:

Solutions that combine with the lignocellulose material before digestion are called cooking liquor will. Their composition depends on the type of lignocellulosic material to be digested and the digestion process used in terms of type and concentration of the constituents Boundaries fluctuate. For example, the cooking liquor can be expressed as 8 to 20% by weight alkali metal base as a percent effective alkali based on the weight of the lignocellulosic material, next to it normally also contain alkali metal carbonate. However, cooking liquor can also, for example, 8 to 15% by weight Alkali metal base expressed as a percent effective

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Alkali (TAPPI T-120 S 61), based on lignocellulose material / and 5 to 40 wt% alkali metal sulfide / expressed as percent sulfidity (TAPPI T-1203 OS-61) / contain. This cooking liquor usually also contains alkali metal sulfate and alkali carbonate, if appropriate also sulfur in an amount of 1 to 5% by weight.

They are used as black eyes after the digestion has taken place used cooking liquor separated from the pulp of the lignocellulosic material. These contain the solubilized accompanying substances of cellulose, for example lignosulfonates, as organic constituents and / or alkali lignins, optionally also hemicelluloses and low molecular weight conversion products of the constituents of Lignocellulosematierals, as inorganic constituents, for example in the Mainly alkali metal sulfate and alkali metal carbonate, as well as bound to acidic organic components Alkali metal base, in addition usually also free alkali metal base, alkali sulfide, alkali sulfite and Alkali thiosulfate. The specific weight of the black liquor fluctuates depending on the concentration of the dissolved Substances generally from 1.05 to 1.2 g / ml. The solids content can, for example, be within the limits move from 10 to 70 wt .-%.

Thick liquor refers to those black liquors that, due to a high solids content of, for example more than 50% by weight are highly viscous at room temperature. Thick liquors can, depending on the

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final process directly by separating pulp or by evaporating black liquors with a low solids content.

The solutions are referred to as green liquors / which contain, for example, 5 to 20% by weight of alkali metal carbonate and contain, for example, 1 to 5% by weight of alkali metal sulfide. They are made of water and that molten salt that is produced when the organic components of the thick liquor are burned. Normally green liquors also contain sodium sulphate, sodium sulphate, Sodium thiosulfate and sulfur. Green liquor, for example, has a specific gravity in the range from 1.1 to 1.30 g / ml.

The alkalis obtained from green liquors by treatment with quick lime are called white liquors. White liquors contain, for example, 80 to 200 g of alkali metal base, 10 to 80 g of alkali metal sulfide and 20 to 50 g of alkali metal carbonate per liter of solution. Usually they also contain alkali metal sulfite, Alkali metal sulfate and alkali metal thiosulfate, optionally also sulfur. Your solid content is, for example, about 10 to 35% by weight, The specific weight of the white liquor is, for example, between 1.1 and 1.3 g / ml.

A particular embodiment of the dispersions according to the invention is characterized in that these additionally contain wetting agents. Cationic, anionic or nonionic wetting agents are used as wetting agents in question, preferably those that are in the

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drive to pulp production as by-products. Examples are black liquor, thick liquor and / or the lignosulfonates or alkali lignins obtainable therefrom. The wetting agents can be obtained based on the weight of the dispersions, in amounts of, for example, 0.01 to 20%, preferably 0.05 to 10 wt .-%, are added. The addition of wetting agents can be done, for example, that before the preparation of the Dispersion powdery wetting agent is added to the powdery substance to be dispersed. The wetting agent but can also be added to the liquid dispersant in liquid or solid form.

Another particular embodiment of the dispersions according to the invention is characterized in that these also contain substances that increase viscosity. As the viscosity-increasing substances come for example water-soluble polymeric compounds such as polyvinyl alcohol and / or methyl cellulose in Question. Thick liquor can also be used, i.e.

for example black liquor concentrated to a solids content of 50 to 70% by weight. Pure concentrated liquor having a solids content of, for example, 64 wt .-%, which is a highly viscous material at 2O ⁰ C, for example, forms at 8O ⁰ C with Nitroanthrachinonverbindungen a stable dispersion. The favorable viscosity-increasing effect of the thick liquor also has an effect in the case of mixtures of 60 parts of thick liquor and 40 parts of water or in the case of mixtures of 50 parts of thick liquor and 50 parts of white liquor. Inorganic substances such as polysilicates, for example

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fumed silica with a special

fish surface of approx. 380 m / g can be used. The use of inorganic, viscosity-increasing substances is not particularly advantageous, because these are not eliminated by incineration and are in the cell material recovery process can enrich. Polyvinyl alcohol is therefore particularly preferred as the viscosity-increasing substances and methyl cellulose are used. The use of thick liquor or mixtures containing thick liquor using water or electrolyte solutions is also beneficial.

Polyvinyl alcohol and / or methyl cellulose are obtained, for example, in amounts of 5 to 20% by weight on the weight of the dispersant / thick liquor in amounts of, for example, 50 to 100% by weight, based on the weight of the dispersant used.

The addition of viscosity-increasing substances has proven particularly useful when using dispersants proven, the density of which differs noticeably from the density of the nitroanthraquinone to be dispersed. at The viscosity-increasing substances can also be used as dispersants, their density stable dispersions at the lower limit of the density range according to the invention, i.e. 1.2 g / ml produce. When using aqueous electrolyte solutions as a dispersant, the

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The use of substances that increase the viscosity of the electrolyte can be saved.

A similar effect, as with the addition of the viscosity-increasing substances, is obtained in the case of the invention Dispersions obtained when carrier dispersions are used as the dispersant. Under the term carrier dispersion is understood in the context of the present invention, a dispersant that already present as a dispersion before the addition of the nitroanthraquinones. Such carrier dispersions are e.g. obtained when using thick liquor or black liquor with concentrated aqueous electrolyte solutions or solid Electrolytes, especially caustic soda or caustic soda, are added. The use of carrier dispersions as a dispersant has the advantage that it allows for the recycling of waste materials produced by the process permits the preparation of the dispersions according to the invention.

The temperature is not important for the preparation, stability and use of the dispersions according to the invention decisive and can fluctuate within wide limits. For practical reasons, the temperature for production, Storage and use between room temperature and the temperature chosen at which below Under normal pressure no noticeable amounts of water evaporate and in this way the specific gravity move the dispersant.

When using thick lye as a wetting agent, as a viscosity-increasing substance and / or as a component

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in the manufacture of a carrier dispersion, a working temperature of 50 is recommended to 9O ⁰ C, because thick liquor solidifies on contact with cold water or electrolyte solution, and is only slowly dissolved or dispersed.

The dispersions according to the invention can be prepared in various ways. So can it Nitroanthraquinone to be dispersed in the optionally with wetting agent and / or viscosity-increasing agent Substituted dispersing agents are stirred in. The nitroanthraquinone to be dispersed can also into the dispersant, e.g., an equal or dense similar aqueous electrolyte solution or The carrier dispersion is stirred in and the resulting dispersion

■ I5 persion subsequently with a wetting agent and / or a viscosity-increasing substance are added. One can also proceed in such a way that one has to disperse the Nitroanthraquinone first mixed with a wetting agent in solid or liquid form and then this mixture into the dispersion medium, e.g. an electrolyte solution or a carrier dispersion, brings in. Furthermore, the nitroanthraquinone to be dispersed can be mixed with the solid electrolyte, for example Sodium hydroxide, optionally together with a wetting agent, mix and add to this mixture Add water or add this mixture to water.

Particularly preferred dispersions according to the invention are characterized in that they contain 30 to 70% by weight, based on the weight of the dispersion, a technical

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niche mixture of nitroanthraquinones contain, and 70 to 30% by weight, based on the weight of the dispersion, of an aqueous solution of sodium hydroxide, Sodium sulfide, sodium sulfite, sodium thiosulfate, sodium carbonate, potassium carbonate, magnesium bisulfite, Calcium bisulfite, ammonium sulfite, sulfuric acid and / or phosphoric acid, preferably of sodium hydroxide and especially potassium carbonate or sulfuric acid, a density of 1.45 to 1.62 g / ml, and optionally 0.05 to 10% by weight, based on the total weight of the dispersion, of wetting agent and, if appropriate, the 50 to 100% by weight aqueous solution is replaced by thick liquor or by a carrier dispersion.

The invention also relates to the use of the dispersions according to the invention, in particular the technical mixtures of dispersions containing nitroanthraquinones, in processes for producing cellulose. The dispersions according to the invention can be fed in the pulp production before the boiling, but advantageously before the impregnation, in which the lignocellulose material is ^{soaked at a temperature of 80 to 100 °} C. with the aqueous solution of the digestion chemicals. The aqueous solution of the digestion chemicals also serves as a conveying medium for charging the impregnator and / or digester with the lignocellulosic material. The dispersions according to the invention can be pumped in doses into the returning solution or into the solution loaded with wood chips,

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optionally also directly into the impregnator or digester. With the aid of the dispersions according to the invention In this pulping process, pulps of excellent uniform quality become obtain.

The dispersions according to the invention are used in such amounts in pulp production used that the amount of nitroanthraquinone added 0.001 to 10 wt .-%, based on the Dry weight of the lignocellulosic material to be processed is.

The preparation of the dispersions according to the invention is simple and can be carried out without special apparatus. The dispersions according to the invention can with the aid of suitable pumps, for example peristaltic pumps, Eccentric screw pumps or piston pumps metered and conveyed through pipelines will. The dispersions according to the invention are stable over long periods of time. At least you can stored for a few days, but generally even for several weeks. As a result of their stability the production of the dispersions according to the invention can be locally separated from the production of pulp take place, for example at the manufacturers of nitroanthraquinones. The preparation of the invention However, dispersions can also be used in the production of pulp, as with the exception of the to dispersing nitroanthraquinones only those substances are required that are used in the production of pulp

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used and / or incurred anyway.

The metering of the dispersions according to the invention is particularly simple. With a given delivery rate A metering pump can be used to meter the dispersed substance in the pulp recovery plant change by adding higher levels of dispersed substance by adding powdered nitroanthraquinone and adjusts lower levels of dispersed matter by adding dispersing agent.

In this way, the dispersions according to the invention the operating conditions of the pulp production are adapted and changed, if necessary without having to change the delivery rate of the dosing pump.

By using the dispersions according to the invention in pulp production processes including pulp bleaching can have the beneficial effect the nitroanthraquinones are optimally used as disintegrating agents. The organic components of the Dispersions according to the invention are also incinerated when the process wastewater is incinerated. The inorganic Components of the dispersions according to the invention, in particular the aqueous electrolyte solutions can be selected so that none of them are extraneous to the process Substances get into the respective pulp production process.

With the aid of the dispersants to be used according to the invention can nitroanthraquinones of a pulpy

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th grain size range in stable dispersions. The grain size of the nitroanthraquinones to be dispersed can be up to 5 mm; preferably the grain size of the nitroanthraquinones to be dispersed is in the range from 0.1 μm to 3 mm. Since the Particle size distribution of the dispersed nitroanthraquinones has no effect on the stability of the dispersions according to the invention, technical mixtures of nitroanthraquinones can be dispersed in such a way that as they arise in technical production.

It is surprising that the dispersions according to the invention meet the requirements for use in pulp production fully meet including pulp bleaching. Stable dispersions will be known to be obtained only when the dispersed particles have a grain size of less than 10 / µm exhibit. In the case of coarser dispersions, the dispersed particles usually settle earlier or later from (see Römpp, Chemielexikon 6th edition, column 6285 (1966)). Particles with a grain size of less than 10 μm but can only be obtained with the help of complex grinding processes. Such grinding processes are at the It is not necessary to prepare the dispersions according to the invention.

A great advantage of the dispersions according to the invention is that they can be prepared with dispersants allow an adaptation to the respective cell

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permit material recovery processes. It can be practical a dispersion according to the invention is made available for each conventional pulp production process in which no non-process substances have to be introduced.

The invention further relates to a method for producing cellulose from lignocellulosic materials in Presence of nitroanthraquinones, which is characterized in that the nitroanthraquinones in Form of the dispersion according to the invention applies.

The process for producing pulp from lignocellulose materials as such are carried out in a manner known per se. For example, these procedures be carried out, by placing lignocellulosic materials in a sulfite solution that is acidic, neutral or can be alkaline, digested and the digestion solution before or after the addition of the lignocellulosic material adding dispersions according to the invention. The dispersions according to the invention can also be used in the known Use pulp recovery processes known as the Kraft process, the soda process, and the polysulfide process are designated. The dispersions according to the invention can also be used in the known oxygen-alkali process for pulp production and / or in the bleaching processes known for pulp production insert.

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example 1

40 g of a technical mixture of nitroanthraquinones (composition: 30.7% by weight 1.8-, 27.1% by weight 1.6-, 23.0% by weight 1.7, 10.0% by weight 1.5, 1.1% by weight 2.7, 1.0% by weight 2.6-dinitroanthraquinone; 0.7 wt% 1-nitroanthraquinone and 6.4% by weight of other nitroanthraquinones; Grain size: 40 to 400μ, πι) are in 60 g Entered 66% aqueous sulfuric acid.

First, a thin, greenish dispersion is obtained, on which part of the dispersed nitroanthraquinone floats as a result of trapped air. A uniform, stable dispersion is obtained by slow stirring.

Example 2

150 g of the technical mixture of nitroanthraquinones described in Example 1 are stirred into a mixture of 90 g of 66% strength sulfuric acid and 10 g of black liquor (density: 1.07 g / ml). A slightly viscous, 60% dispersion is obtained. The sediment separating from the dispersion can still be stirred well even after standing for a long time.

Example 3

40 g of the technical mixture of nitroanthraquinones described in Example 1 is converted into a dispersion (Carrier dispersion) stirred in, which by stirring 9.6 g of black liquor (density: 1.07 g / ml) and 50.4 g of sodium hydroxide solution (density: 1.51 g / ml) had been prepared.

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It becomes thick and stable for several months Obtained dispersion that can be pumped without difficulty.

Example 4

40 g of a mixture of nitroanthraquinones (composition: 33% by weight 1.6%, 21.7% by weight 1.8%, 21.6% by weight 1.7, 6.5% by weight, 1.5, 1.9% by weight, 2.6 and 1.8% by weight of 2.7-dinitroanthraquinone and 1.4% by weight of 1-nitroanthraquinone; Grain size 100-500 nm) are dispersed in 60 g of 74% phosphoric acid (density 1.565 g / ml).

A stable, thin-bodied dispersion is obtained, from which even after storage for 2 months there is still no Solid has settled.

Example 5

50 g of the nitroanthraquinone mixture described in Example 1 are dispersed in 50 g of 53% strength potash solution.

First of all, a thin-bodied dispersion is obtained from which part of the dispersed substance becomes trapped as a result Air floats. After destroying the foam layer by carefully stirring a uniform, stable dispersion obtained which does not change even after storage for two months.

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Example 6

233 g of the nitroanthraquinone mixture described in Example 4 are added to a mixture of 90 g of 50% strength potash solution and stir in 10 g of black liquor (density; 1.07 g / ml).

A stable, viscous 70% dispersion is obtained, which is easy to pump and meter excels.

Example 7

40 g of 1-nitroanthraquinone (grain size 50 to δΟΟμπι) are in 57 g of 51% potassium iodide solution, the 3 g of black liquor (Density: 1.07 g / ml) were added, dispersed.

A uniform, stable dispersion is obtained, which can be easily stirred and pumped even after 2 months.

Example 8

40 g powdery 1.5-dinitroanthraquinone will be stirred into 57 g of 46% calcium bromide solution mixed with 3 g of black liquor (density: 1.07 g / ml) .

After slowly stirring the components, a stable, low-viscosity, uniform dispersion is obtained.

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Example 9

40 g of 1.8-dinitroanthraquinone (max. Particle size: about 100μΐη) are in a solution of 3 g of black liquor (1/07 g / ml), 29 g water and 28 g anhydrous zinc chloride are stirred in.

A thin, stable dispersion is obtained which is still undamaged even after eight weeks of storage. is changing.

Example 10

80 g of the 1-nitroanthraquinone described in Example 7 are stirred into 120 g of a carrier dispersion composed of 84% by weight of 43% sodium hydroxide solution and 16% by weight of black liquor (solids content: 16%) had been.

A viscous, uniform, stable dispersion is obtained, which is easy to pump and meter excels.

Example 11

40 of the mixture described in Example 4 of nitroanthraquinones g at 8O ⁰ C with 48 g of concentrated liquor (density: 1.25 g / mL at 8O ⁰ C, solid content: 64 wt .-%) and mixed with 12 g of saturated sodium carbonate solution. The density of the dispersing agent is at 2O ⁰ C 1.34 g / ml.

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A very viscous dispersion which is stable at room temperature is obtained.

Examples 12 and 13

100 g of the technical mixture of nitroanthraquinones described in Example 1 are mixed with 1 g of dry Lignosulfonate mixed with grinding. The grain size of the mixture after grinding is about 40 up to 100μΐη. 50.5 g of this mixture are in 49.5 g 50% potash solution or 49.5 g 66% sulfuric acid are stirred in.

Stable, uniform 50% strength dispersions are obtained which are unchanged even after storage for two months and which are characterized by good pumpability and meterability.

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Claims (1)

Claims 1) j dispersions of nitroanthraquinones, characterized in that they contain the nitroanthraquinones in liquid dispersants the same or similar Density like the nitroanthraquinones contain. 2) dispersions according to claim 1, characterized by that pure compounds, solutions or dispersions are used as liquid dispersants will. 3) dispersions according to claim 1 and 2, characterized in that the liquid dispersant aqueous solutions of metal oxides, hydroxides and / or salts and / or acids and / or solutions of nitrogen bases and / or of salts of nitrogen bases can be used. 4) dispersions according to claim 1 to 3, characterized in that the liquid dispersant aqueous solutions of oxides, hydroxides, sulfides, sulfites, bisulfites, sulfates, thiosulfates, Carbonates, chlorides, bromides, iodides, nitrates, nitrites of sodium, potassium, ammonium, Calcium and / or magnesium and / or sulfuric acid and / or phosphoric acid are used will. 5) dispersions according to claim 1 to 4, characterized in that the liquid dispersant Le A 19 966 130017/0316 ORIGINAL INSPECTED aqueous solutions of sodium hydroxide, sodium sulfide, Sodium sulfite, sodium bisulfite, sodium sulfate, Sodium thiosulphate, sodium nitrite, sodium carbonate, Potassium hydroxide, potassium carbonate, potassium nitrate, potassium sulfide, magnesium bisulfite, Calcium bisulfite and / or ammonium sulfite can be used. 6) dispersions according to claim 1 to 5, characterized in that the liquid dispersing agent aqueous solutions of sodium hydroxide, potassium carbonate or sulfuric acid can be used. 7) dispersions according to claim 1 and 2, characterized in that the liquid dispersant from thick liquor or black liquor and solid electrolytes or concentrated aqueous electrolyte solutions prepared carrier dispersions are used. 8) dispersions according to claim 1 to 7, characterized in that the grain size of the to be dispersed Nitroanthraquinones up to 5 mm. 9) dispersions according to claim 1 to 8, characterized in that the grain size of the to be dispersed Nitroanthraquinones ranges from 0.1 µm to 3 mm. - | 0) dispersions according to claim 1 to 9, characterized in that that their content of nitroanthraquinones 5 to 80 wt .-%, based on the weight of the dispersions. Le A 19 966 130017/0316 11) dispersions according to claim 1 to 10, characterized characterized in that they are as nitroanthraquinones 1-, 2-nitroanthraquinone, 1.5-, 1.6-, 1.7-, 1.8-, 2.6- and / or 2.7-dinitroanthraquinone contain. 12) dispersions according to claim 1 to 10, characterized in that they are used as nitroanthraquinones Contain mixtures of mono- and / or dinitroanthraquinones, as they are in mono- or dinitration of anthraquinone or in the nitration of mononitroanthraquinone mixtures in technical Scale and subsequent separation of the isomers valuable as dye intermediates from the nitration products. 13) dispersions according to claim 1 to 12, characterized characterized in that they additionally contain wetting agents. 14) dispersions according to claim 13, characterized in that they are by-products as wetting agents contained in pulp production. 15) dispersions according to claim 13 and 14, characterized in that they are used as a wetting agent black liquor, Contain thick liquor and / or lignosulfonates and / or alkali lignins obtainable therefrom. 16) dispersions according to claim 13 to 15, characterized characterized in that they use the wetting agents in quantities Le A 19 966 130017/0316 from 0/01 to 20% by weight based on weight the dispersion. 17) dispersions according to claim 1 to 16, characterized in that that they also contain viscosity-increasing substances. 18) dispersions according to claim 17, characterized in that that they are used as viscosity-increasing substances polyvinyl alcohol, methyl cellulose and / or thick liquor. 19) Process for the preparation of dispersions of Nitroanthraquinones, characterized in that one uses the nitroanthraquinones in liquid dispersants, which have the same or a similar density as the nitroanthraquinones, dispersed. 20) Use of the dispersions according to claim 1 to 18 in a process for the production of pulp from Lignocellulosic materials. Le A 19 966 130017/0316