JPS5840589B2 - Method for producing β-crystalline phase linear quinacridone - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing β-crystalline phase linear quinacridone.

Conventionally, linear quinacridone (hereinafter referred to as quinacridone) represented by the following formula (1) has been used.

) are known to have α-crystalline phase, β-crystalline phase, and r-crystalline phase, all of which have a bright red or purple color tone and are heat resistant, weather resistant, solvent resistant, and resistant to solvents. It is an organic pigment with excellent chemical properties.

Among these, the β crystal phase has the strongest blue tinge among the three crystal phases, and has a wide range of uses as a unique reddish-purple organic pigment.

The following methods are known to date to obtain quinacridone in the β-type crystal phase.

(1) A method in which crude quinacridone is ground in a ball mill in the presence of common salt and a nonpolar organic solvent such as an aromatic hydrocarbon or a halogenated aromatic hydrocarbon.

(2) A method in which quinacridone is made into an alkali salt using caustic alkali in alcohol, and then hydrolyzed using water or dilute sulfuric acid.

(3) A method in which crude quinacridone is dissolved in methyl sulfuric acid and diluted with water.

(4) A method in which a concentrated sulfuric acid solution of quinacridone and aromatic sulfonic acid is dropped into water.

(5) A wet cake obtained by condensing 2.5-dianilinoterephthalic acid with polyphosphoric acid is heated at about 120 to 200°C under high pressure with (a) an aqueous inorganic alkali solution and an organic solvent.
or (b) heated to about 120-200°C under pressure with an inorganic alkali aqueous solution, and then heated under high pressure with an organic solvent.
A method of heating to 20-180°C.

However, these methods have drawbacks as shown below.

That is, method (1) requires the use of a large amount of inorganic salt such as common salt and a long treatment time during ball milling.

Furthermore, the crude quinacridone must be dried once, and an aqueous wet cake cannot be used.

Method (2) also does not substantially utilize a water wet cake and uses a large amount of an expensive organic solvent, which requires removal and recovery of this solvent and is extremely complicated in terms of operation.

Methods (3) and (4) require a large amount of sulfuric acid when dissolving quinacridone, and it is difficult to regenerate methyl sulfuric acid and sulfuric acid.

Furthermore, from an environmental standpoint, waste sulfuric acid must be treated after use, and this method is also not industrially advantageous.

Method (5) is an excellent method that uses an aqueous paste, but it is not necessarily a satisfactory method because it requires the use of a high-temperature and pressure-resistant container that requires equipment costs.

The present inventors have arrived at the present invention as a result of various studies aimed at improving these points.

That is, the present invention provides linear crude quinacridone obtained by oxidizing 6,13-dihydroquinacridone in an alcoholic caustic alkali with an organic oxidizing agent.
The present invention relates to a method for producing β-crystal phase linear quinacridone, which is characterized by carrying out a heating rearrangement treatment in a benzyl alcohol mixed system.

Next, the present invention will be explained in more detail.

The crude quinacridone to be heat-treated in the present invention is a linear crude quinacridone obtained by oxidizing 6,13-dihydroquinacridone in an alcoholic caustic alkali with an organic oxidizing agent. is caustic soda or caustic potash,
Further, as the organic oxidizing agent, sodium m-nitrobenzenesulfonate, nitrobenzene, orthonitrotoluene, etc. are used.

Specifically, the crude quinacridone is, for example, 10 parts by weight of 6
, 13-dihydroquinacridone, 200 parts of ethyl alcohol, 25 parts of water, 20 parts of sodium m-nitrobenzenesulfonate, and 4 parts of sodium hydroxide were added together, heated and stirred under reflux for 4 hours, and after cooling, The product is obtained by filtering off and washing with hot ethyl alcohol followed by displacement with water.

In the present invention, the crude linear quinacridone obtained as described above is heat-treated together with a water-alkali-benzyl alcohol mixed system.

Linear crude quinacridone is obtained as a wet cake, but in the present invention, this wet cake can be directly subjected to rearrangement treatment without drying, which is industrially advantageous.

Of course, the wet cake may be suitably dried beforehand and then subjected to the heating rearrangement treatment.

This heating rearrangement treatment is carried out at 70° C. or higher, preferably under reflux. By heating for 3 to 8 hours, the rearrangement to the β type is completed.

This heat treatment is usually performed under stirring.

Caustic soda and caustic potash are suitable as the alkali to be used.

In addition, the water used is 10 to 30% of the crude quinacridone.
The concentration of alkali used is 25 to 40 times the weight of water.

The appropriate amount of benzyl alcohol to be used is about 1 to 10 times the weight of crude quinacridone.

The method of the present invention has advantages over the above-mentioned known methods, such as being able to directly convert crude quinacridone into the β-form without intermediate drying, and requiring only one conversion step, and its industrial value is high. Extremely large.

Hereinafter, the present invention will be explained in more detail with reference to Examples.
The present invention is not limited to the following examples unless it exceeds the gist thereof.

Example 1 10 parts by weight of 6,13-dihydroquinacridone, 200
1 part of ethyl alcohol, 25 parts of water, 20 parts of sodium m-nitrobenzenesulfonate, and 4 parts of sodium hydroxide were added together, and the mixture was heated and stirred under reflux for 4 hours.

After cooling, wash with hot ethyl alcohol, followed by displacement with water.

102 parts of the wet filtrate thus obtained (cake purity: 9.
5 parts) was transferred to a mixed system consisting of 70 parts by weight of sodium hydroxide, 100 parts by weight of water, and 40 parts by weight of benzyl alcohol, and refluxed for 6 hours.

After cooling, it was filtered, washed with hot alcohol, followed by water until the filtrate was neutral, and dried under vacuum at 50°C.

The powder obtained in this way was analyzed by X-ray diffraction.
It shows the characteristic peak of β-type quinacridone described in Publication No.-13833, and it can be seen that it is β-type quinacridone.

When this product was used in printing inks and paints, it exhibited a purple color tone and had excellent fastness properties.

Claims (1)

[Claims] A β-crystalline phase characterized in that linear crude quinacridone obtained by oxidizing 16,13-dihydroquinacridone with an organic oxidizing agent in an alcoholic caustic alkali is subjected to heat rearrangement treatment in a water-alkali-benzyl alcohol mixed system. Method for producing linear quinacridone.