JPS6045170B2 - Method for molding 1,4,4a,9a-tetrahydroanthraquinone - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention involves the wet collection and separation of the hot gas from the catalytic gas-phase oxidation reaction of naphthalene, and the separation of 1,4-naphthoquinone (hereinafter abbreviated as NQ) and butadiene into an inert organic compound. The present invention relates to an industrial method for obtaining a molded product of THAQ from a reaction solution containing 1,4,4a,9a-tetrahydroanthraquinone (hereinafter abbreviated as THAQ) as a main component obtained by reaction in a solvent.

THAQ is used as a raw material for dye intermediates, agricultural chemicals, and other anthraquinones and their derivatives. THAQ is
Generally, it is produced by the Diels-Alder reaction between NQ and butadiene, but it is dehydrogenated by air or light, or enolized in the presence of some acid components.
4-dihydroanthrahydroquinone (hereinafter referred to as DHAHQ)
), and dihydroanthraquinone (hereinafter referred to as I
It is chemically unstable, producing DHAQ (abbreviated as DHAQ).

This tendency is particularly strong in THAQ obtained using industrial NQ. Therefore, in order to stably store or transport THAQ, it is preferable to form it into flakes, granules, or pellets. However, industrially THAQ
In order to produce NQ, the raw material NQ can be purified to some extent (for example, by washing an organic solvent solution of naphthoquinone with an organic polybasic alkali salt solution as shown in JP-A-51-8257). It is necessary to use a material containing acid components such as phthalic acid and benzoic acid in an amount of about 0.1% by weight or more. These acid components are introduced into the THAQ solution, which is the reaction product of the NQ and butadiene, during the Diers-Alder reaction, and after desolvation, the liquid TH
Enolization, that is, isomerization of THAQ to DHAHQ, is promoted until AQ is molded. The melting point of purified THAQ is 102-4°C, while the melting point of the aforementioned industrial product THAQ is about 90-95°C. On the other hand, the melting points of DH and AHQ, which are isomers of THAQ, are 205T to 210℃.
and as the content of DlIAHQ increases, liquid THAQ
DFlAHQ crystallizes out, and in the molding process DHAH
Troubles such as Q depositing in pipes etc. and clogging occur, making it impossible to mold liquid THAQ. As a result of intensive research to overcome such drawbacks, the inventors of the present invention discovered that TH
Solvent step of AQ solution and then obtained liquid THAQ
In the molding process, it is recognized that the main factors that affect enolization are the acid component content in NQ and the processing temperature, and furthermore, in controlling these conditions and molding, it is necessary to control the DHAHQ content in liquid THAQ. The present invention was completed by discovering that a THAQ molded product can be obtained without any trouble by keeping the amount below a certain level. The present invention wet-collects hot gas containing NQl phthalic anhydride obtained by catalytic gas-phase oxidation reaction of naphthalene using an aqueous medium, and separates NQ from the aqueous slurry of NQ and phthalic acid produced.
After removing the acid component in the NQ to 0.4% or less based on the NQ, the solvent was removed from the THAQ reaction solution obtained by reacting the NQ and butadiene in an aromatic hydrocarbon solvent.
The resulting molten THAQ was distilled off at a temperature below 120°C.
How to mold THAQ, which is characterized by maintaining the temperature below ℃ or above the melting point and molding by a known method! lies in the law.

In the present invention, an industrial grade product is generally used as the raw material NQ.

As the NQ used in the present invention, it is preferable to use highly purified NQ from which acid components have been completely removed, but NQ itself is inflammatory to the skin and is difficult to handle. If this is done, it would be extremely disadvantageous industrially, so the use of high-purity NQ is usually not considered. Industrial NQ is usually NQ obtained by catalytic gas phase oxidation reaction of naphthalene.
NQ can be separated from a hot gas containing phthalic anhydride and naphthalene, for example, by wet collection and separation using an aqueous medium. For example, NQ obtained by washing and collecting the reaction product gas in the catalytic gas phase oxidation of naphthalene with water or an aqueous medium containing maleic acid, phthalic acid, etc.
The aqueous slurry of phthalic acid and phthalic acid is heated to dissolve the phthalic acid in water, and then only the NQ is extracted into an inert organic solvent (substantially an aromatic hydrocarbon such as toluene, xylene, etc.). The NQ solution obtained in this way contains about 0.3 to 0.8% phthalic acid and 0.1 to 0.2% of the NQ.
% of benzoic acid, so it is washed with a weakly alkaline aqueous solution such as disodium phthalate to remove phthalic acid and organic acids such as benzoic acid. The NQ solution thus obtained is used for the reaction with butadiene. The lower the acid component in the NQ solution, the better, especially 0.2
% or less, but since the acid component usually exists in the NQ solution purified in this way at a concentration of 0.1 to 0.4% (relative to NQ), the acid component is also present in the reaction between the NQ and butadiene. Even when the resulting reaction solution containing THAQ as a main component is heated, it is difficult to completely prevent the production of DHAHQ due to enolization of THAQ.

The aromatic hydrocarbon solvent used in the present invention is preferably a solvent that can be relatively easily distilled off by distillation or steam distillation at 120° C. or lower under normal pressure or reduced pressure.

Examples include benzene, toluene, and xylene. In particular, ortho-xylene is preferred industrially. That is, NQ is selectively extracted from the reaction product gas by catalytic gas phase oxidation of naphthalene as a solution of aromatic hydrocarbons,
The purified NQ solution is fed to the Diels-Alder reaction. This is because molten THAQ can be easily obtained by removing the solvent. The reaction between NQ and butadiene is carried out in the above-mentioned aromatic hydrocarbon solvent using known methods such as NQ.
A polymerization inhibitor such as t-butylcatechol and N
Adding 1 mol or more of butadiene to Q, 90 to 1
A solution of THAQ can be easily obtained by reacting at 50° C. and then removing butadiene.

The method for distilling off the organic solvent from the THAQ solution is as follows:
A method of removing the solvent by distillation or steam distillation at normal pressure or reduced pressure at 120° C. or lower is adopted, and the conditions at that time are determined depending on the type of organic solvent used.

However, in any case, below 120℃,
Preferably, a temperature condition of 100° C. or less must be maintained. This is because, as shown in FIG. 1, at temperatures above 120° C., THAQ is rapidly enolized by the acid component derived from the raw material NQ to produce DHAHQ. DHAH
If Q is contained in THAQ in an amount of 10% or more, DH and AHQ will crystallize in the subsequent molding process, causing problems such as clogging and making molding impossible. Therefore, when the acid content is high, that is, when the acid content is 0.3% or more, the time required for removing the solvent must be shortened. For example, a thin film evaporator is used to remove the solvent in a short period of several tens of seconds. However, D in THAQ is usually treated in a commonly used vacuum concentrator, either batchwise or continuously with a suitable residence time.
Suppress the generation of HAHQ to 10% or less as much as possible. Next,
The molten THAQ from which the solvent has been removed is molded using a molding device.

Examples of the molding device include a flaker, a pelletizer, a spray cooling granulation device, and a granulation molding machine. Industrially, flakers are used because they are cheap. Types of flakers include belt type, table type, drum type, etc., and drum type devices are preferred because they are compact and are easy to operate in terms of temperature conditions and other aspects. When molding THAQ using such molding equipment, the most important point is to maintain the content of DHAHQ contained in the molten T]IAQ at 1% by volume or less while it remains in the molding process. That's true. As mentioned above, when DHAHQ exceeds 15%, molten TH
This is because DHAHQ crystallizes from AQ.

If the temperature is raised to dissolve this, enolization will progress and the production of DHAHQ will be accelerated. Also, DHA
If the temperature is raised above 200°C, which is the melting point of HQ, regardless of the formation of HQ, DIU-Q will change to anthrone, etc., which is not preferable. Therefore, the temperature is maintained at 120°C or lower, preferably 100°C or lower, above the melting point (approximately 93'C due to the inclusion of impurities), and the content of DHAHQ in molten THAQ is reduced to 10% or less in the molding process. must be treated as such. For example, when molten THAQ containing 4% by weight of DHAHQ after desolvation and 0.3% by weight of acid component in molten THAQ is continuously treated with a flaker, the holding temperature is 100°C. The average residence time may be within about 5 hours before molding. Preferably, the process from the THAQ solution to molding is continuous, for example, the THAQ solution is desolvated in a rotary thin film evaporator,
It is then preferably processed in a short period of time by continuous flaking or spray cooling to solidify. The flaky molded TIIAQ obtained by the method of the present invention is extremely convenient for stable storage or transportation over long periods of time.

Furthermore, THAQ obtained according to the present invention may be partially oxidized to DHAQl, further oxidized to produce anthraquinone, or THAQ may be halogenated and then nitrated to produce 1
- Can be used as a synthetic raw material in the production of nitroanthraquinone.

Hereinafter, the present invention will be specifically explained with reference to Examples.

However, % represents weight %. Example 1 NQ2 obtained by washing and collecting the gas produced by the catalytic vapor phase oxidation reaction of naphthalene, and then extracting it using ortho-xylene.
The 2% ortho-xylene solution was washed with 0.3 times the volume of a 2.7% aqueous solution of disodium phthalate.

The resulting NQ solution contained 0.3% phthalic acid and 0.02% benzoic acid based on NQ. The N
0.054 parts of t-butylcatechol and 18 parts of butadiene are reacted with 1 (1) part of the Q solution and the NQ solution in an autoclave at a reaction temperature of 120° C. for 13 hours.

After the reaction was completed, ortho-xylene was distilled off from the reaction solution at 95° C. for 3 hours to obtain 29.4 parts of molten THAQ based on 10 CE of NQ solution.

The molten THAQ contained 6% DHAHQ. 7 A flaking test was conducted using 50 kg of the molten THAQl.

The flaker used was a drum type flaker, the liquid supply method was a dip charge method, the drum cooling method was a spray method, and the drum had a diameter of 318wn x width of 300WrIn and a surface area of 0.3d. The test conditions were a drum rotation speed of 7 RPM, a drum cooling temperature of 41 to 43°C, and molten THAQ was flaked while maintaining it at 100°C. The average molding amount was 45 kg/hr, and the test was completed after about 3 hours, during which time it was extremely easy to form flakes, and the amount of DHAQ in the final molten THAQ was about 10%.
It was hot. Example 2 In Example 1, the NQ solution obtained by washing with a 2.7% aqueous solution of disodium phthalate was
It was further washed with 5 times the amount of warm water at about 80° C. to obtain a 22% NQ ortho-xylene solution containing 0.08% phthalic acid and 0.02% benzoic acid based on NQ.

Using this solution, reaction, distillation of the solvent, and molding were carried out in the same manner as in Example 1, but flaking was extremely easy, and the amount of DHAHQ in the final molten THAQ was approximately 5%. It was hot.

[Brief explanation of the drawing]

FIG. 1 shows the relationship between the acid content in THAQ and the DHAHQ production rate.

Claims (1)

[Claims] 1 1 obtained by catalytic gas phase oxidation reaction of naphthalene
- 1,4-naphthoquinone is separated from the aqueous slurry of 1,4-naphthoquinone and phthalic acid produced by wet collection of hot gas containing 4-naphthoquinone and phthalic anhydride using an aqueous medium. The acid component inside is 1.4-
From a 1,4,4a,9a-tetrahydroanthraquinone reaction solution obtained by reacting the 1,4-naphthoquinone and butadiene in an aromatic hydrocarbon solvent after removing the naphthoquinone to 0.4% or less. The solvent was distilled off at 120°C or lower, and the obtained solvent molten 1, 4, 4a, 9a
- A method for molding 1,4,4a,9a-tetrahydroanthraquinone, which comprises maintaining the tetrahydroanthraquinone at a melting point of 120° C. or higher and molding it by a known method. 2. The method according to claim 1, wherein the aromatic hydrocarbon solvent is benzene, toluene, or xylene. 3 The acid content in 1,4-naphthoquinone used for the reaction with butadiene is 0.2 relative to 1,4-naphthoquinone.
2. A method according to claim 1, comprising removing less than %. 4. The method according to claim 1, which comprises distilling off the solvent from the 1.4.4a.9a-tetrahydroanthraquinone reaction solution at 100°C or lower. 5. The method according to claim 1, wherein molten 1,4,4a,9a-tetrahydroanthraquinone is held and molded at a temperature of 100°C or lower.