NO803624L - DISPERSIONS OF DINITROANTRAKINONES PROCEDURE FOR THEIR PREPARATION AND THEIR USE - Google Patents

Abstract

For the Contracting States : BE, DE, FR, GB, IT, SE 1. Dispersions of dinitroanthraquinones for use in processes for the production of pulp, characterized in that they contain the dinitroanthraquinones, in finely divided form, surface-active agents and water and/or liquid organic compounds with boiling points above 80 degrees C. For the Contracting State : AT 1. Process for the preparation of dispersions of dinitroanthraquinones for use in processes for the production of pulp, characterized in that dinitroanthraquinones, surface-active agents and water and/or liquid organic water-miscible compounds with boiling points above 80 degrees C are group with one another.

Description

Dinitroanthraquinones exert a beneficial effect in certain methods for the production, bleaching of cellulose from lignocellulosic materials such as wood, straw and bagasse when they are used in amounts from 0.001 to 10% by weight, referred to the dry weight of the lignocellulosic material.

The dinitroanthraquinones are usually present in the form

of powder. However, the use of such powdered dinitroanthraquinones in processes for the production of cellulose from lignocellulosic materials and their bleaching presents difficulties. If the powdered denitroanthraquinones are added immediately to the lignocellulosic material to be digested, the finer parts of the •dinitroanthraquinones are easily dusted in the environment. In this way, the intended use is not only avoided, but also leads to strain on people working in the vicinity of the addition site and can even cause dust explosions. In addition, due to the relatively small amount of 'the ..necessary dinitroanthraquinones a uniform distribution difficult./A uniform distribution of the dinitroanthraquinones is, however, "inevitable to achieve a uniform cellulose quality.

An even distribution of the dinitroanthraquinones is also made difficult by the fact that these are usually not only very poorly soluble in the aqueous digestion solutions used in cellulose production, but also poorly wetted. Because of. the poor wetting does not allow the finer parts of the powdered dinitroanthraquinones to settle, or only with difficulty to stir in and instead float unmoistened, possibly under the entrapment of air, on the surface.

As dinitroanthraquinones have a relatively high specific gravity (e.g. 2,7-dinitroanthraquinone at 20°C has a specific gravity of 1.558 g/cm 3 ), the coarser parts of the powdered dinitroanthraquinones settle quickly when mixed with water or in the absorption solution and after a short period of time at the bottom of the vessel forms a compact layer that is only difficult to re-swirl. The addition of dinitroanthraquinones directly to the cooking liquor in the mixture of lignocellulosic materials and cooking liquor, or in the form of a slurry of water, is therefore no way to achieve the necessary even distribution of dinitro-

the anthraquinones.

It has now been found that the above-mentioned difficulties can be avoided by using dinitroanthraquinones when these are used in the form of specific dispersions. These dispersions are obtained by dispersing dinitroanthraquinones in finely divided form together with their ide- in water and/or organic water-miscible liquids whose boiling point is above 80°C. •

The invention relates to the following dispersions of dinitroanthraquinones for use • i.' methods for producing cellulose from lignocellulosic materials, the dispersion being characterized by the fact that they contain dinitroanthraquinones in finely divided form, tehs.ides and water and/or organic water-miscible liquids whose boiling point is above 80°C.

Within the framework of the invention, the term "cellulose production" is understood to mean all methods and procedural steps of putting Lingng in Lingng and acting on cellulose-containing material in a chemical way; Examples of this are alkaline, neutral and acidic digestion methods for lignocellulosic materials such as wood, straw, bagasse and grass, as well as bleaching methods for partially or strongly digested lignocellulosic materials.

As representatives of dinitroanthraquinones to be dispersed according to the invention, dinitroanthraquinones which in addition to the nitro groups have one or more additional substituents also come into consideration.

As representatives of dinitroanthraquinones to be dispersed according to the invention, the following should be mentioned, for example: 1,5-, 1.6-, 1.7-, 1.8-, 2.6- and 2.7 dinitroanthraquinones; 1,3-dinitro-4-aminoanthraquinones; 1. 5-dinitro-4,8-dihydroxyanthraquinone; 1,8-dinitro-4,4-dihydroxy-anthraquinone. - With dinitroanthraquinones, it is within the scope of the invention also to understand partially nuclear hydrogen derivatives of dinitroanthraquinones and/or their tautomeric forms.

Preferably, the dispersion according to the invention contains mixtures of unsubstituted dinitroanthraquinones. Such ■mixtures are produced, for example, by "the technical nitration of anthraquinone and/or mononitroanthraquinones. In particular, the dispersion according to the invention can contain mixtures of the nitroanthraquinones that arise when one dinitrates anthraquinones on a technical scale or nitrites monoanthraquinone mixtures and from the resulting nitration products separate those which dyestuff intermediates valuable isomers, eg 1-nitro-, 1.5-dinitro- and/or 1.8-dinitroanthraquinone.- These latter' mixtures contain as essential constituents 1.5-, 1. 6-,'' 1; 7-, 1.8-, 2.6- and 2.7-dinitroanthraquinone ■ As dinitroanthraquinone, particularly preferred mixtures contain, for example, 0-3% by weight 1-nitroanthraquinone, 5 to 12% by weight 1''. 5-dinitroanthraquinone, 15 to 35% by weight 1.6 -dinitroanthraquinone, 15 to 35% by weight 1,7-dinitroanthraquinone, 15 to 50% by weight 1,8-dinitroanthraquinone, 0.5 to 3% by weight 2,6-dinitroanthraquinone, and 0.5 to 3% by weight 2,7-dinitroanthraquinone.

The dispersible dinitroanthraquinones according to the invention preferably consist of 80% by weight of particles with a particle size of less than 10 µm, especially less than 5 µm.

Surfactants for dispersions according to the invention include cationic, non-ionic and, above all, anionic surfactants.

Quaternary, long-chain and/or ox.ethylated amines, quaternary pyridinium compounds or long-chain phosphonium compounds should, for example, be mentioned as cationic surfactants. Long-chain thereby means a carbon chain with at least 4 C atoms, preferably with at least 6 C atoms.

The example of cationic surfactants is in particular: Trimethyl-hexadecy1-ammonium bromide, cety1-pyridin-ium bromide, laury1-dimethylbenzy1-ammonium chloride, monoester of triethanolamine with stearic acid as formic acid or acetic acid salts, N-laury 1-methylbenzimidazole hydrochloride and dodecyl-trimethyl1- phosphonium bromide.

A large part of these compounds of additional relevant cationic surfactants are discussed in K. Lindner, Tenside-Textilhilfsmittel-Waschrohstoffe, Volume 1, pages 963-1041

(1964).

Internal ionic surfactants include, for example, formation products of alkylene oxides, especially ethyl oxide to higher fatty acids, alcohols, phenols, acid amides, mercaptans, amines or alkylphenols. The learning products can, for example, be obtained from 5 to 50 mol of alkyl oxide and 1 mol of fatty acid, alcohol, phenol, acid amide, mercaptan>amine or alkylphenol, which have at least 4, preferably at least 6 -C atoms. As non-ionic surfactants, it also comes to the fore. products of allylene oxides, especially ..ethylene oxide to polypropylene oxide or to sugars as well as oxyethylated and non-oxyethylated sugar derivatives such as fatty acid esters of pentaerythritol or sucrose.

The example of non-ionic surfactants is in particular:

Learning products of 5' to 20 moles of ethylene oxide

to stearic acid, oleyl alcohol, polypropylene glycol, nonylphenol, oleic acid amide and dodeslamin.

A large part of these compounds and further applicable non-ionic surfactants are, e.g. discussed in N. Schonfeldt, Grenzflachenaktive Ethylenoxid-Addukte, pages 42 to 95 (1976) and in K. Lindner, Tenside-Textilhilfsmittel-Wasch-rohstoffe, Volume 1, pages 837 to 917, (1964).

Preferably, the dispersion according to the invention contains anionic surfactants. Anionic surfactants include, for example, alkylsulfonates, sulfated unsaturated, higher fatty acids, sulfonates of polycarboxylic acid esters, alkylbenzenesulfonates, sulfated aliphatic alcohols with an inorganic polybasic acid such as phosphoric acid or especially sulfuric acid in acid esters transferred learning products of ethylene oxide to higher amines, acids, phenols or alcohols, as well as lignin sulphonates or derivatives of lignin sulphonates, condensation products of aromatic sulphonic acids and formaldehyde and polyphosphates.

The example for anionic surfactants is in particular: Sodium dodecyl sulfonate, sodium lauryl sulfate, sodium dodecylbenzene sulfonate, sodium dibutyl naphthalene sulfonate,. acidic sulfuric acid esters of formation products of 2 mol of ethylene oxide on 1 mol of nonylphenol, sodium dioctyl sulfosuccinate, condensation products of cresol, 2-naphthol-6-sulfonic acid and formaldehyde, as well as sulfonic acid of naphthalene, terphenyl or ditolyl ethers.

A large part of these compounds and other relevant anionic surfactants are described in K. Lindner, Tenside-Textilhilf smittel-Waschrohstoffe, Volume 1, pages 571 to 835

(1964).

The dispersion according to the invention contains surfactants, particularly preferably equation sulfonates and/or condensation products of aromatic sulfonic acid and formaldehyde.

The dispersion according to the invention can also contain mixtures of anionic and non-ionic surfactants.

Water and/or organic liquids miscible with water, whose boiling point is above 80°C, preferably above 100°C, are used as dispersants for the dispersion according to the invention.

As such liquids, all polyhydric alcohols, further liquid acid amides, come into consideration above all. Examples include: Di-, Tri- and polyols such as ethylene glycol, propylene glycol, glycerol and their ethers such as glycol monoethyl ether, diethylene glycol monomethyl ether and diethylene glycol monoethyl ether; such as acid amides formamide and dimethylformamide. These organic liquids not only serve as a dispersant, but when used together with water also serve as a means of reducing the frost sensitivity of the dispersion. In the dispersion according to the invention, water and organic liquids can exist in desirable mixing ratios. The content of the dispersion according to the invention of these organic liquids is preferably 5 to 20% by weight referred to the weight of the overall dispersion: The dispersion according to the invention can for example contain 30 to 70% by weight dinitroanthraquinones in finely divided form, 0.5 to 30% by weight surfactant or surfactant mixture and at least 30% by weight of water and/or organic water-miscible liquids. Preferably, the dispersion contains according to the invention

45 to 65% by weight dinitroanthraquinones in finely divided form, 1 to

10% by weight surfactant or surfactant mixtures and at least 35% by weight water' and/or organic liquids miscible with water.

The dispersion according to the invention can in addition to

the above-mentioned components contain additional substances,

for example preservatives, anti-drying agents and/or agents for stabilizing the dispersion.

As 'preservative' there are substances such as e.g. prevents mold formation and/or bacterial attack. Common preservatives are suitable for this, e.g. sodium pentachlorophenol, addition products of paraformaldehyde on aliphatic alcohols such as benzyl alcohol ■ and/or formaldehyde solutions. The preservatives can be added to the dispersion according to the invention, for example in amounts from 0 to 3% by weight, preferably in amounts of ;0.05 to 0.5% by weight referred to the weight of the dispersion.

Common soluble anti-drying agents such as polyalkylene glycols, e.g. polyethylene glycols with molecular weights from 200 to 2000, and polyhydroxyalkylurethanes as well as preferably the organic and water-miscible liquids already mentioned as dispersants or as means for reducing frost sensitivity. The drying inhibitors can be added to the dispersion according to the invention, for example in amounts of 2 to 20, preferably 5 to 10% by weight, referred to the dispersion. weight.

As agents that have a stabilizing effect on the dispersion, the following should be mentioned, for example: highly dispersed silicic acid, magnesium and aluminum silicate, montmorillonites, which may also contain organic bases, chalk and/or thickeners such as methyl cellulose, hydroxymethyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, as well as polyacrylate and /or polymethacrylate and/or their mixed polymers, polyvinyl alcohols, as well as combinations of the aforementioned substances. The stabilizers can be added to the dispersion according to the invention, for example in amounts from 0 to 2, preferably 0.1 to 1% by weight, referred to the total weight of the dispersion.

The dispersion according to the invention can e.g. is prepared by mixing the dinitroanthraquinones to be dispersed, surfactants or the surfactant mixture, water and/or the water-miscible organic liquid whose boiling point is above 80°C and any stabilizer in the desired ratio and adding to a conventional wet crusher. Suitable wet crushers are e.g. knuckles,. grinders, ball mills, rotor-stator mills, dissolvers, corundum disc mills and swing mills. Preferably, high-speed pipework mills with grinding bodies are used whose grinding bodies preferably have a diameter of 0.1 to 10 mm. The painting takes place..preferably that long

until at least 80% by weight of the dinitroanthraquinone particles have a grain size below 10 µm, preferably below 5 µm. Preservatives and/or anti-drying agents can be added to the dispersion before or after painting.

If the dispersion according to the invention is to be used

in cellulose production processes that are carried out in an alkaline environment, it can be advantageous to add smaller quantities of an alkaline reacting substance to the dispersion. Such alkaline reacting substances are e.g. aqueous lye or aqueous lye. These substances can be added to the dispersion in amounts from 0 to 2% by weight, referred to the total weight of the dispersion.

The dispersion according to the invention is used in the process for producing cellulose from lignocellulosic materials. The dispersion according to the invention can be added during cellulose production before boiling, preferably, however, before impregnation, where the lignocellulose material is impregnated at a temperature from 80 to 100°C

with the aqueous solution of the dissolution chemicals. IN

in the cases in which the aqueous solution of the dissolving chemicals also serves as a carrier medium for coating the impregnation and/or the digester with lignocellulosic material, the dispersion according to the invention can also be introduced into the receding solution or into the solution charged with chops as well as immediately into the impregnating agent or digester.

The dispersion according to the invention is used when used in methods for the production of cellulose, usually in an amount of from 0.01 to 10% by weight, referred to the weight of the lignocellulosic material.

With the aid of the dispersion according to the invention, the desired fine distribution of the dinitroanthraquinones in the digestion liquid is achieved. The dispersion according to the invention is stable and pumpable, i.e. they can be dosed using suitable pumps, for example long pressure pumps, eccentric screw pumps or piston pumps and transported through pipelines. Because of. due to their stability, they can be stored for several weeks or even months without dispersed substances settling or floating up, respectively only settling down or floating up so little that with simple means, e.g. slow-moving stirrers can again be brought into the dispersed state. In the form of the dispersion according to the invention, the dinitroanthraquinones can be dosed using simple volume and quantity measurements.

When using the dispersion according to the invention

since cellulose bleaching is included in methods for cellulose production, the beneficial effect of the dinitroanthraquinones can be utilized optimally.

It is to be described as very, very surprising that the dispersion according to the invention completely fulfills the requirements for use in cellulose production;': including . cellulose peeling because it the small, however not negligible solubility of dinitroanthraquinones in water was to be reckoned with their recrystallization or particle growth and therefore the finely divided state could not be expected and thus stable dispersions could be maintained for a long time.

The invention further relates to a method for producing cellulose from lignocellulosic materials in the presence of dinitroanthraquinones, the method being characterized in that the dinitroanthraquinones are used in the form of the dispersion according to the invention.

The process for cellulose production of lignocellulosic materials as such is carried out in a manner known per se. For example, these methods can be carried out by placing lignocellulosic materials in a sulphite solution which can be acid neutral or alkaline and adding the dispersion according to the invention to the digestion solution before or after adding the lignocellulosic material. The dispersion according to the invention can also be used in the known cellulose production methods which are referred to as the kraft method, the soda method and the polysulphide method. The dispersion according to the invention can also be used in the known oxygen-alkali process for cellulose production and/or in the bleaching processes known for cellulose production.

With the help of the method according to the invention, due to the even distribution of dinitroanthraquinones in the digestion solution cellulose of particularly uniform quality.

Example 1

600 g of a technical mixture of dinitroanthraquinones (composition: 30.7 wt% 1.8-, 27.1 wt% 1.6-, 23.0 wt% 1.7-, 10.0 wt% 1.5-, 1.1 wt% 2 . .'7-, 1.0 wt% 2-6 dinitroanthraquinone; 0.7 wt% i-nitroanthraquinone and 6.4 wt% other nitroanthraquinones), 318 g of water, 60 g of ethylene glycol and 20 g of a condensation product of a md .1 '.naphthalene sulphonate and 1 mol of formaldehyde and 2 g of a preservative based on a formaldehyde-releasing compound are mixed in a dissolver. (high-speed pipework) and ground in a pipework mill until 80% of the dinitroanthraquinones have a grain size below 10 µm.

A flowable stable dispersion of the dinitro-anthraquinone mixture is obtained. The dispersion is pumpable and can be mixed without difficulty into wood digestion sludge from the sulphite, kraft and soda processes.

Example 2

500 g of a mixture of dinitroanthraquinones (composition: 3 3 wt% 1.6-, 21.7 wt% 1/8-, 21.6 wt% 1.7-,

6.5% by weight of 1.5, - 1.9% by weight of 2.6-, and 1.8% by weight of 2.7-dinitroanthraquinone and 1.4% by weight of 1-nitroanthraquinone) are mixed with 480 g of ethylene glycol and 20 g of sodium dinaphthyl tertane sulfonate in a dissolver and then ground in a bead mill until 80% of the dinitroanthrachione mixture has a grain size below 5 µm.

A stable pumpable dispersion is obtained which can be easily pumped and distributed in wood digestion liquors from the sulphite, kraft and soda processes.

Example 3

• 600 g of the dinitroanthraquinone mixture mentioned in example 1, 60 g ethylene glycol, 313 g water and 20 g sodium dinaphthyl methanesulfonate are ground as indicated in example 1. The suspension is thickened with aluminum silicate, made alkaline with 3 g 50% caustic soda .

A pumpable, stable dispersion is obtained.

Example 4

600 g of the mixture of dinitroanthraquinones mentioned in example 1 is ground with 60 g of propylene glycol, 315 g of water and 20 g of lignin sulfonate as indicated in example 1. The suspension is mixed with a preservative based on a formaldehyde addition product to berizyl alcohol and made alkaline with 3 g 50% caustic soda.

A stable, flowable dispersion is obtained which allows

distributed in the wood digestion end from the :kraft and soda process.

Claims (10)

1. Dispersion of dinitroanthraquinones for use in methods for cellulose production, characterized in that they contain the nitroanthraquinones in finely divided form, surfactants and water and/or liquid organic water-miscible compounds whose boiling point is above 80°C. 2. Dispersions according to claim 1, characterized in that at least 80% by weight of the dinitroanthraquinones consist of particles of a grain size below 10 µm. 3. Dispersions according to claim 1, characterized in that at least 80% by weight of the dinitroanthraquinones consists of particles of a grain size below 5 µm. 4. Dispersions according to claims 1-3, characterized in that they contain anionic surfactants as surfactants. 5. Dispersions according to claim 1^4, characterized in that they contain lignin sulfonates and/or condensation products of aromatic sulfonic acids and formaldehyde as anionic surfactants. 6. Dispersions according to claims 1-5, characterized by those as organic water-miscible liquids whose boiling point is above 80°C, contain di-, tri- and polyols and/or their ethers and/or acid amides. 7. Dispersions according to claims 1-6, containing 30 to 70% by weight of dinitroanthraquinones, 0.5 to 30% by weight of surfactants and at least 30% by weight of water and/or organic, water-miscible liquids whose boiling point is above 80°C. 8. Dispersions according to claims 1-6, characterized in that they additionally contain preservatives, drying agents and/or agents for stabilizing the dispersions. 9. Process for producing dispersions according to claims 1-8, characterized in that dinitroanthraquinones, surfactants and water and/or organic with water-miscible liquids whose boiling point is above 80°C are ground together until at least 80% by weight of the dinitroanthraquinones consists of particles with a grain size below 10/ um. 10.. Use of the dispersion according to claims 1-8 in methods for producing cellulose from lignocellulosic materials.