JPS60158132A - Method for oxidizing organic compound - Google Patents

Abstract

PURPOSE:To obtain advantageously the aimed compound, by reacting an organic compound with a ceric salt in the presence of a water-immiscible organic solvent and tetralin in an aqueous solution of an acid in the reaction system to prepare the aimed oxidation product corresponding to the above-mentioned raw material. CONSTITUTION:An organic compound, preferably a polycyclic aromatic hydrocarbon, particularly naphthalene is reacted with a ceric salt, preferably ceric sulfate in a water-immiscible organic solvent, preferably benzene or a derivative thereof inert to the reaction, e.g. a 1,1-dialkyl-substituted alkylbenzene or chlorobenzene, containing about >=10%, preferably about >=15% tetralin in an aqueous solution of an acid, preferably sulfuric acid at 20-60 deg.C, preferably 30-55 deg.C to give the aimed oxidation product corresponding to the above-mentioned raw material, preferably quinone, particularly 1,1-naphthoquinone advantageously such as easy separation of the solvsnt layer from the aqueous layer after the reaction.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention involves reacting a ceric salt on a convertible organic compound such as naphthalene in an acid aqueous solution in the presence of an organic solvent that is immiscible with water. The present invention relates to a method for industrially advantageous production of corresponding oxidation products such as 1,4-naphthoquinone.

For example, an oxidizable organic compound such as naphthalene is oxidized using an aqueous solution of a ceric salt to produce ■,4-naphthoquinone, etc., and as a result, the ceric salt is reduced to produce a cerous salt. Methods for regenerating and reusing ceric salts by electrolytically depolymerizing them are well known, and typical examples thereof are as follows. In other words,
Publication No. 9-34978 describes a method in which a polycyclic aromatic hydrocarbon such as naphthalene is dissolved in an inert organic solvent that is immiscible with water, and the solution is reacted with an acid aqueous solution of a ceric salt. Water-immiscible inert organic solvents which are disclosed and suitable for the process include saturated aliphatic hydrocarbons such as n-hexane; ethers such as diethyl ether; benzene; ethylene dichloride, dichloride Only chlorinated aliphatic hydrocarbons such as methylene or carbon tetrachloride are mentioned. On the other hand, in the specifications of previously filed Japanese Patent Application No. 58-64315 and Japanese Patent Application No. 58-91452, the present inventors disclosed that tert-butylbenzene (hereinafter referred to as
We proposed 1,1-dialkyl-substituted alkylbenzenes (hereinafter abbreviated as tert-alkylbenzenes) such as "TBBJ" and chlorobenzene as new inert organic solvents for the above reaction. These solvents are particularly stable outside of the oxidation reaction caused by ceric salts, and also have excellent solubility of oxidation products such as quinone. Among the inert organic solvents listed above, the industrially preferred ones are 1. from the viewpoint of toxicity, specific gravity, solubility for oxidation products, especially quinone, and vapor pressure. te
These are benzene compounds such as rt-alkylbenzene, chlorobenzene, and hibenzene.

However, when naphthalene and ceric sulfate are reacted in an aqueous sulfuric acid solution using such an inert organic solvent, after the reaction, the solvent, water, and the sulfuric acid produced by the reaction are present between the solvent layer and the aqueous layer. A reaction method in which a mixed mud layer consisting of cerous crystals is generated, and the sulfur has a high concentration of ceric, so that crystals of cerous sulfate precipitate after the reaction. (slurry method) or a reaction method that does not precipitate cerous sulfate after the reaction (
Since it is produced no matter which method (solution method) is adopted, separation of the solvent layer and aqueous layer after the reaction is extremely difficult, resulting in a large loss of expensive cerium and l+'l-naphthoquinone.
Even if we try to recover cerium and 1-4-naphthoquinone from mud, there are many complicated steps and the cost is high.
Since it is not practical, a one-piece method without the above-mentioned drawbacks has been sought.

The present inventors have made extensive studies to solve the industrial drawbacks of the method of oxidizing organic compounds with an aqueous ceric salt-acid solution using the inert organic solvent. By using tetralin as an inert organic solvent or by making tetralin coexist with the inert organic solvent, the formation of the mixed mud layer is minimized, and as a result, the solvent layer and water layer after the reaction are separated. The present invention was achieved based on the discovery that the separation of

That is, the gist of the present invention is to react an organic compound and a ceric salt in an aqueous acid solution in the presence of an organic solvent that is immiscible with water, thereby producing a poration product such as a quinone corresponding to the organic compound. A method for oxidizing an organic compound, characterized in that the oxidation reaction is carried out in the presence of tetralin.

Organic compounds used as raw materials for the oxidation method of the present invention include:
Compounds (referred to as oxidizable organic compounds) that are oxidized to produce corresponding oxidation products such as quinones outside the reaction area of the oxidation method of the present invention, specifically, for example, polycyclic aromatic carbonization. Examples include hydrogen and its derivatives, toluene compounds, and secondary alcohols. Further details 17< refers to polycyclic aromatic hydrocarbons and their derivatives and oxidation products obtained therefrom (hereinafter, the numbers in parentheses represent the oxidation products obtained from raw materials outside the parentheses), such as naphthalene (
1,4-naphthoquinone), 2-argylnaphthalene (2-alkyl-1,4-naphthoquinone or 7-alkyl-5)8-naphthoquinone) such as 2-methylnaphthalene,
1-nitronaphthalene (5-nitro-1,4-naphthoquinone), anthracene (9,10-anthraquinone),
Examples include ethyl anthracene (ethyl-LIO-anthraquinone), phenanthrene (9,10-phenanyl-lenequinone), and haphenyl (2-phenylbenzoquinone). Examples of toluene-based compounds and oxidation products obtained from them include toluene (benzaldehyde), toluene (tolylaldehyde), methylanisole (anisaldehyde), and nitrotoluene and trobenzaldehyde. In addition, secondary alcohols and oxidation products obtained from them include, for example, 4-
Examples include dodecanol (4-dodecanone). Among these organic compounds and the oxidation products obtained therefrom, the method of the present invention is capable of converting naphthalene to 1+4-
It is particularly advantageously applied industrially to the production of naphthoquinones.

The ceric salts used as oxidizing agents in the method of the present invention include salts of mineral acids such as sulfates, nitrates, perchlorates, acetates, chloroacetates, fluoroacetates, or ceric salts. Examples include methanesulfonate,
Industrially, ceric sulfate is usually preferred.

In addition, in order to stably exist the ceric salt aqueous solution used in the oxidation reaction in the method of the present invention, the acid aqueous solution must be sufficiently acidic.

As such an acid, an acid corresponding to the anion forming the ceric salt as described above can be used, but a
Mineral acids, particularly sulfuric acid, are preferred from the viewpoint of stability when regenerating cerous salts, which are produced by reduction as a result of oxidation reactions with nicerium salts, into ceric salts by electrolytic oxidation.

The concentration of such acid is usually 5 to 15, preferably 6 to 1.
Selected from a range of 2%.

The concentration of the ceric salt in the above acid aqueous solution is not particularly limited, and for example, it may be used at a level higher than its solubility in the initial stage of the reaction, that is, in the form of a slurry. However, it is generally at least 0.3 mol/1, preferably at least 0.3 mol/71, or its dissolution 1. The reaction is carried out at a ceric salt concentration below f. For example, in a ceric sulfate-sulfuric acid aqueous solution, the -1 mt ceric acid concentration is usually 01
~0.6 mol/l is used for reaction.

In the method of the present invention, it is an essential requirement that the oxidation reaction of an organic compound with a ceric salt in an acid aqueous solution be carried out in the presence of tetralin, and tetralin may be used alone or in a water-immiscible solution as described above. It can also be used as a mixture with an organic solvent. In the case of the latter mixture of tetralins, other industrially preferred water-immiscible organic solvents to achieve the object of the invention include benzene, which is substantially inert to the oxidation reaction of the process of the invention. Alternatively, a benzene derivative can be mentioned, and examples of the benzene derivative include ], ]1-dialkyl-substituted alkylbenzene, chlorobenzene, and the like. More specifically, the preferred 1.1-dialkyl-substituted alkylbenzene has the general formula: (wherein, R+ + R2+ Ra represents an alkyl group, and the number of carbon atoms in these alkyl groups varies from 3 to 6).
In the tert-alkylbenzene having one tertiary alkyl group having 4 to 7 carbon atoms, R1゜R2 and R3 include linear or branched alkyl groups, but generally linear ones are used. selected from. It takes ter
Examples of t-alkylbenzene include tert-butylbenzene, tert-pentylbenzene, I+1
-dimethylphthylbenzene (tert-hexylbenzene>, 111-dimethylpentylbenzene (tert-hexylbenzene)
heptylbenzene), etc. On the other hand, the total number of carbon atoms of R11R2 and R3 in the general formula (1) is 6.
In other words, if the number of carbon atoms in the tertiary alkyl group exceeds 7, the boiling point becomes high, making it difficult to recover the solvent, and the solubility of the target oxidation product, such as quinone, decreases. It's not scary. When a mixture of tetralin and such other organic solvent is used in the method of the present invention, in order to achieve the object of the present invention, it is necessary to use a mixture of tetralin and other organic solvents, although it varies depending on the content of the other organic solvent. The content of tetralin may be about 10 parts or more, preferably 15 parts or more.

Before using the substantially inert reactive organic solvent used in the present invention (used alone or as a mixture of tetralin), the oxidizable organic compound such as the raw material polycyclic aromatic hydrocarbon is generally dissolved. Usually, the amount of solvent is set so that the concentration of the dissolved raw material is 1% or more, but in order to increase the reaction rate, it is preferable to use an amount that can bring the concentration close to the solubility of the raw material at the reaction temperature. For example, when the raw material is naphthalene, the above-mentioned solvent is generally used in an amount that can bring the degree of dissolved naphthalene to 20 to 60%, usually 40 to 50%.

In the method of the present invention, the reaction temperature is 20 to 60°C, preferably 30 to 55°C, and the reaction time is generally 10 minutes to 2 hours, although it depends on stirring conditions, raw material concentration, and reaction temperature. It will be held in The above reaction temperature is 30°C, especially 20°C.
This is because the reaction rate becomes slow at temperatures below .degree. C., and tetralin becomes easily oxidized at temperatures above 60.degree. However, it is possible to increase the reaction rate of the raw materials to almost 100% in one reaction. However, in order to increase the selectivity of the desired reaction product, such as 1,4-naphthoquinone, the reaction rate of the raw material is suppressed to 50 parts or less, and the remaining raw material (for example, naphthalene) and the above-mentioned inert organic solvent are used as a mixed solvent. The mixed solvent solution after the above reaction, which is immiscible with water and in which the first target product (e.g. naphthoquinone) is dissolved, is directly used in the next reaction using the naphthoquinone as a raw material, e.g. Diel-Alder reaction with butadiene. and convert the naphthoquinone into a water-soluble second target product, 1ν4 r
After substantially fractional removal of the first desired product, e.g. naphthoquinone, by methods such as separation into an aqueous layer as the disodium salt of 4a + 9a-tetrahydroanthraquinone or other methods, the raw material (1 By repeating the process of adding the required amount of Naphthalene and circulating it to react with the ceric salt, as a result, the raw material (Naphthalene)
For example, it is often advantageous from an industrial standpoint to substantially increase the reaction rate of naphthalene to approximately 100 degrees.

The method of the invention is generally carried out as follows. In other words, a sulfuric acid aqueous solution of a ceric salt such as ceric sulfate with a predetermined concentration and a raw material such as naphthalene are mixed with an organic solvent of tetralin or water in which tetralin coexists with a predetermined amount. The solution dissolved in the solvent is reacted under pressure at a predetermined temperature for a predetermined time, and then the solvent layer and the aqueous layer are separated [7. Some of the products still dissolved in the aqueous layer are extracted using the above organic solvent. and combine with the previously separated solvent layer. This combined solvent layer is then processed depending on the purpose. For example, in order to obtain a quinone such as 1v4-naphthoquinone, the desired product is crystallized or dried using a membrane solvent under reduced pressure.

In addition, if the product is to be used subsequent to the next reaction step, it is used for that purpose after an appropriate post-treatment such as washing with water.

In the above method, the reaction step and the separation step of the solvent layer and the aqueous layer can also be carried out by a multistage countercurrent process instead of combining several reactors and separation vessels, etc.

Since the aqueous layer from which the solvent layer was separated in the above step mainly contains the cerous (trivalent) salt produced by the reaction, this aqueous layer is again subjected to the oxidation reaction of the method of the present invention. For this purpose, it is necessary to oxidize and regenerate the cerium salt to ceric salt. Although a chemical regeneration method using hydrogen peroxide or the like has been proposed as a regeneration method, a method using electrolytic oxidation is generally used. For example,
No. 978, the process of the present invention is applied to a batch or continuous electrolytic cell using an electrical connection made of an inert conductive material such as platinum, platinized titanium or carbon. The aqueous solution of cerous salt produced in the oxidation reaction will be delivered to the ship and electrolytically oxidized to convert the cerous salt into ceric salt. During this electrolysis, it is preferable to provide a porous partition wall or an ion exchange membrane between the electrodes.

The electric temperature is generally 40~40°C due to the corrosion resistance of the material.
Since it is carried out at 60° C., which matches the temperature conditions of the method of the present invention, the regeneration method by electrolytic oxidation described above can be carried out industrially and economically.

In addition, in the regeneration process using the above-mentioned 8'tIR conversion,
From an industrial standpoint, it is necessary to maintain high current efficiency, so
Generally, it is not economical to reduce the concentration of cerous salt to 0, and usually the electrolysis is finished with the cerous salt remaining, and the cerous salt containing a certain amount of the cerous salt is removed.
The acid aqueous solution is subjected to the reaction step.

Next, the present invention will be explained in more detail with reference to Examples. Note that "%" used in this specification means "by weight" unless otherwise specified.

Example 1 Tert-butylbenzene (hereinafter, [TBB
, abbreviated as l. ), chlorobenzene (rOA-
It is abbreviated as BZj. ) or benzene (hereinafter abbreviated as "Bz") and tetralin (hereinafter abbreviated as "TLN J") in the proportions shown in Table 1 below. (Abbreviation:
Np) −(F, P.

79.8°C; 8 min 023 (0.0 as thionaphthene)
The predetermined amount shown in Table 1 of Section 98) Contained] was added. Then cerous sulfate (Oe2(S04)3) 2.
951 (f), 10t) 2mol/[), sulfur 11W
g Nicerium CCe (SO4)2 ) 723t (
0,420mol/71), im enemy 4.51? and 51.81 mj of an aqueous solution consisting of 48.52 f of water (the concentration of sulfuric acid as a sulfuric water bath liquid is 85%)! , put in the rotor for magneti and Kustahler, and make 100 (l r,
Pom, pay with.

The reaction was carried out at 50° C. for 30 minutes while stirring. After one core, it was allowed to stand still and the state of formation of mud at the interface between the organic solvent layer (hereinafter abbreviated as "oil layer") and water layer was observed, and then benzene 201M was added as an extraction solvent. The reaction product was extracted, and the aqueous layer separated from the oil layer was further heated with 20 rJ of benzene.
The whole oil layer was extracted twice using a gas chromatograph, and the aqueous layer was analyzed using a high performance liquid chromatograph. The results are summarized in Table 1 below and expressed as a ratio.

Table 1 (Note) (-): Trace amount, (+): Small amount, (++): Slightly large amount.

Example 2 ce(SO4)2 (each concentration shown in Table 2 below) charged in a glass lined reactor with a stirrer with a capacity of 100β,
ce2(so4)3 (0,15mol/n) and H2
Naphthalene (F, P, 79.8°C; thionaphthene 0.98%
3,31 kg (containing) and 4.3 kg of TBB and/or TLN as the reaction solvent, respectively, as shown in Table 2 below.
Add 28 kg, stir and react at 50°C for 30 minutes,
The results shown in Table 2 below were obtained.

Table 2 As is clear from the results in Tables 1 and 2, when TLN is used as a sole solvent, the formation of interfacial mud between the oil layer and the water layer after the reaction is a small-scale laboratory reaction. There is no such thing at all, and there are only traces of it even in approximately 1009 large-scale industrial reactions. On the other hand, when conventional favorable inert reaction solvents such as TBB, C1-Bz or Bz are used, the formation of the interfacial mud is somewhat common even in laboratory small-scale reactions, much less in industrial large-scale reactions. In the reaction, a large amount (approximately 3
It reaches the 6th section. ), which makes it difficult to separate the oil layer and the water layer, and also makes it difficult to recover the cerium and the produced 1,4-naphthoquinone without much loss. However, if TLN is used as a mixed solvent in which TLN is 10 or more in the case of TBB, 20 or more in the case of C1)-Bz, and 30 or more in the case of Bz, the above-mentioned interfacial sludge can be formed. Since the amount of 1,4-naphthoquinone produced is very small or trace, separation of the oil and water layers after the reaction is extremely easy in any scale reaction, and cerium and the 1,4-naphthoquinone produced can be easily recovered with almost no loss. It becomes possible.

Furthermore, when TLN is used in place of part or all of the TBB solvent, the solubility of the 1,4-naphthoquinone produced at 50°C was measured, and as shown in Table 3 below, the solubility was approximately 10 to 30%. increased. That is, the method of the present invention has an industrial advantage in that the amount of solvent used can be reduced more than ever before.

Table 3 Patent applicant: Kawasaki Chemical Industries, Ltd. Representative Patent Attorney Tsune Ogawa Department

Claims (1)

[Claims] (1) An organic compound and a ceric salt are reacted in an aqueous solution in the presence of an organic solvent that is immiscible with water to produce an oxidation product such as a quinone corresponding to the organic compound. A method for oxidizing an organic compound, characterized in that the oxidation reaction is carried out in the presence of tetralin. (2) The method according to claim 1, wherein the organic compound is a polycyclic aromatic hydrocarbon and the corresponding oxidation product is quinone. (3) The aromatic hydrocarbon is naphthalene, and the quinone is 1
, 4-naphthoquinone. (4) The method according to claim 1, wherein the ceric salt is ceric sulfate. (5) Claim 1 in which the acid aqueous solution is an aqueous solution of sulfur.
The method described in section. (6) The method according to claim 81, wherein the organic solvent is benzene or a benzene derivative that is substantially inert to the oxidation reaction. The reaction is carried out in the presence of claim 6, wherein the benzene derivative is 1,1-sialgyl-substituted alkylbenzene (however, ],]1-dialkyl-substituted alkyl has 4 to 7 carbon atoms) or chlorobenzene. (10) The method according to claim 1, wherein the reaction temperature is 20 to 60°C. (11) 11.) The method according to claim 10, wherein the temperature of the reaction source r is 30 to 55°C.