JPS588373B2 - Production method of quinizarin (1,4-dihydroxyanthraquinone) - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Quinizarin, an important intermediate in dye production, is commercially available from Ullmanns Encyclop. Ndie
Dertechnischen Chemie,
in the presence of boric acid in sulfuric acid according to the method described in 3rd edition (1953), volume 3, pages 669-670, or with boron trihalide and/or trihalogen according to DE 2014566 A1. It is produced by the reaction of phthalic anhydride and p-chlorophenol at a temperature of 170 to 210°C in the presence of a boron complex.

The quinizarin is isolated by dilution of the melt with water and separation of the precipitated reaction product, optionally after treatment with an alkaline agent and in the presence of an oxidizing agent.

The 1,4-dihydroxyanthraquinone obtained by this technique and method is purer at lower production temperatures and purer at higher sulfuric acid concentrations.

However, this reaction is very slow when carried out at 180°C, which poses an economic problem;
℃, the purity of the product remains unsatisfactory.

Performing the reaction with a higher concentration of sulfuric acid increases the purity of the reaction product but reduces the yield.

The lower the sulfuric acid concentration, the greater the amount of acid used.

In either case, a large amount of waste sulfuric acid is generated, and its treatment by neutralization and the removal of the large amount of salts produced during this process are ecologically and economically important.

Surprisingly, applying essentially smaller amounts of highly concentrated sulfuric acid at higher reaction temperatures reduces waste sulfuric acid by at least 50%.
It has been found that 1,4-dihydroxy-anthraquinone can be obtained in good yields and purity at least as good as the known method.

The new process involves the reaction of p-chlorophenol with phthalic anhydride in at least 25% oleum in the presence of boron trioxide at a temperature of 180-220°C, preferably 200-210°C.
It consists of carrying out continuously or discontinuously at ℃ without applying pressure.

The reaction product obtained can, if desired, be worked up in known manner using alkaline agents and optionally in the presence of oxidizing agents.

Both starting materials may be reacted in stoichiometric amounts.

However, it is advantageous to apply the inexpensive phthalic anhydride in an excess of up to 1.5 times, especially up to 1.3 times, the stoichiometric amount.

Usually the reaction is carried out using 35% oleum in a weight ratio of fuming sulfuric acid to sotalic acid of 1:1 to 4:1, preferably 1.1 to 1.5:1.
The ratio of boron trioxide to phthalic anhydride is 1:2 to 1:4.

The concentration of fuming sulfuric acid used is not critical and is about 70
It can also be expressed as a percentage.

The new process is carried out for example at 100 DEG -150 DEG C., preferably at 120 DEG-13 DEG C., while stirring in at least 25% oleum.
Boron trioxide is added at 0°C.

Then phthalic anhydride at 130-150°C, then p
- add the chlorophenol and then heat the reaction mixture to 180-220° C., advantageously 200-210° C., with good mixing;
Heat to 0°C and keep at this reaction temperature for 6-15 hours.

After the reaction is completed, the mixture is cooled to 160-170°C, and the hot reaction mixture is poured into 4-5 times the amount of water, and treated under reflux cooling for 2-5 hours at a temperature of up to 100°C.

The product is then filtered hot, optionally washed until neutral with the application of a weakly alkaline agent, and dried.

The amount of waste sulfuric acid per 1k9 of crude quinizarin produced is determined by the conventional technology (Ullmanns Encyklop! di
e dert. echnischen Chemi
e, 4th edition, Vol. 7, p. 604, 1973). 3 kg, compared to only 1.3 kg according to the new method of the present invention. Only 7 kg is produced.

Example 1 sulfuric acid monohydrate in a 500 ml sulfonation flask
2 4.5 9-6 Add 8ml of 62% oleum 1
44L? = When 72ml is added, the temperature becomes 45-50°C.
rises to.

Then, when 50 g of boron trioxide is added while stirring, the temperature rises to 120-125°C.

This requires approximately 20 minutes. A milky solution forms.

The flask contents were heated to 150°C, then 130~
At 150 DEG C., 160 g of phthalic anhydride and then 104 g of p-chlorophenol were added.

The reaction mixture is then heated to 205±2° C. and kept at this temperature for 14 hours.

After the reaction was completed, the reaction product was cooled to 160-170°C and diluted with 20% water.
00ml and then boiled under reflux with stirring for 4 hours.

After that, when hot, suction the tears, wash with warm water until neutral,
Dry in vacuo at 60-70°C.

170-175 g of "crude quinizarin" (approximately 90%) is obtained.

The "crude quinizarin" yield is 90% of theory (calculated with p-chlorophenol).

The "crude quinizarin" can be purified by known purification operations such as sublimation, recrystallization or treatment with alkaline agents such as dilute sodium hydroxide solution or aqueous sodium bicarbonate solution or with sodium carbonate or ammonia (in which case oxidizing agents such as sodium hypochlorite or chlorine). (sodium acid may be added).

A yield of "pure quinizarin" of 80% or more of the theoretical value (calculated with p-chlorophenol) is thus obtained.

Claims (1)

[Claims] 1. Phthalic anhydride, characterized in that the reaction between phthalic anhydride and p-chlorophenol is carried out in at least 25% oleum in the presence of boron trioxide at a temperature of 180 to 220°C. A method for producing quinizarin by the reaction of and p-chlorophenol. 2. The method according to item 1, wherein the reaction is carried out at 200 to 210°C. 3. The method according to item 1 or 2 above, wherein 3p-chlorophenol and phthalic anhydride are used in a stoichiometric ratio of 1:1 to ]:1.5. 4 The weight ratio of oleum and phthalic anhydride is 1:1 to 4:1.
The method described in any one of the preceding sections 1 to 3 used in . 5 Boron trioxide and phthalic anhydride in a weight ratio of 1:2 to 1:
4. The method described in any one of 1 to 4 above.