JPH04108751A - Production of 2,6-dihydroxy naphthalene - Google Patents

Abstract

PURPOSE:To profitably produce the subject compound in high yield by oxidizing 2,6-diisopropyl naphthalene with molecular oxygen in the presence of an aromatic heterocyclic compound containing a nitrogen atom as a hetero atom in the molecule, and subsequently decomposing the oxidation product with an acid. CONSTITUTION:When 2,6-diisopropyl naphthalene (DIPN) is oxidized with molecular oxygen and subsequently decomposed with an acid to produce 2,6-dihydroxy naphthalene useful as a raw material for heat-resistant resins, etc., an aromatic heterocyclic compound such as pyridine containing an nitrogen atom as a hetero atom in the molecule is added to the reaction system in an amount of 0.01-100mol.%, preferably 0.1-70mol.%, based on the raw material DIPN to largely improve the conversion of the DIPN, heighten the yield and selectivity of the oxidation product to be decomposed into the objective compound with the acid and reduce the amount of hydrogen peroxide used in the next acid decomposition reaction, thereby profitably providing the objective compound in a high yield.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention provides 2,6-dihydroxynaphthalene (hereinafter referred to as D
This invention relates to a method for producing DHN, in particular a method for producing DHN, in which a peroxide obtained by oxidizing 2,6-diisopropylnaphthalene (hereinafter abbreviated as rPN) with molecular oxygen is acid-decomposed. It is.

DHN, which is the object of the present invention, is a compound useful as a raw material for heat-resistant resins and the like.

[Conventional technology 1] As a conventional method for producing HN, a method of sulfonating naphthalene or β-naphthol and melting it with an alkali is known, but the production process is complicated and a large amount of inorganic salts are produced as by-products. , there was a problem as an industrial production method 7 Also, 2.6-bis=(2-hydroxyisopropyl)
A method for producing DHN by oxidizing and acid decomposing naphthalene (hereinafter abbreviated as OCA) with hydrogen peroxide in the presence of an inorganic acid in acetonitrile or dioxane (Japanese Patent Publication No. 1983-
54697, Japanese Unexamined Patent Publication No. 63-22532) are also known, but high-purity OCA is pre-dipped into DIPN.
Moreover, it has the disadvantage that more than 2 moles of hydrogen peroxide are required per 1 mole of OCA.

On the other hand, DIPN was oxidized with molecular oxygen to produce the corresponding hydroperoxide, 2,6-bis(2-hydroperoxyisopropyl)naphthalene (hereinafter abbreviated as DHP).
There is a method to obtain DHN by decomposing it with acid.
There are two methods for oxidizing IPN with molecular # elements, for example:
A method of oxidizing an aromatic hydrocarbon having a secondary alkyl group such as cumene with a molecular element
93156) and a method of oxidizing with molecular oxygen in a disease medium such as chlorobenzene (Japanese Patent Application Laid-Open No. 1983-100).
558) and a method of oxidizing an organic carboxylic acid with molecular hydrogen in the presence of an alkali metal salt in an inert hydrocarbon solvent (Japanese Unexamined Patent Publication No. 63-255241).

[Problems to be Solved by the Invention j] In the method described in JP-A-61-93156, aromatic hydrocarbons having a secondary alkyl group such as cumene also react with the corresponding hydroperoxide. Therefore, there is a drawback that an operation to separate these is required.

Also, JP-A-61-100558 and JP-A-63
In the method disclosed in Japanese Patent No. 255241, the oxidation reaction is carried out in an inert organic solvent, so it is necessary to recover the solvent.

The purpose of the present invention is to increase the selectivity of DHP in the above-mentioned oxidation reaction, to eliminate the need for IN+solvent, to reduce the amount of hydrogen oxide used per pass, and to achieve a high yield of IN, which is industrially advantageous. The purpose is to provide a manufacturing method.

[Means for Solving the Invention] The present invention provides an aromatic compound containing a nitrogen atom as a hetero atom in the molecule during the oxidation reaction of DIPN. ! The selectivity of DHP is increased by adding a ring compound.

This solves the above problems.

That is, the present invention provides a method for producing DHN in which DIPN is oxidized with molecular oxygen and the resulting product is decomposed with acid, and the oxidation reaction is carried out by the presence of an aromatic heterocyclic compound containing a nitrogen atom as a heteroatom in the molecule. D) A method for producing IN, which is characterized by carrying out the following steps.

Basic aqueous solvent The oxidation reaction of DIPN with molecular oxygen is generally carried out in a basic aqueous solvent.

The basic compound used is preferably an alkali metal compound.6 Specifically, alkali metal hydroxides such as sodium hydroxide, potassium hydroxide, and lithium hydroxide; alkali metal carbonates such as sodium carbonate and potassium carbonate; Alkali metal bicarbonates such as sodium hydrogen and potassium hydrogen carbonate; alkali metal phosphates such as sodium phosphate, potassium phosphate, sodium hydrogen phosphate, potassium hydrogen phosphate, sodium dihydrogen phosphate, and potassium dihydrogen phosphate; , and alkali metal boron compounds such as sodium tetraborate.

These can be used either alone or in a mixture of two or more in any proportion.

The amount of these alkali metal compounds added in the aqueous solvent is preferably 30% by weight or less based on water.

The amount of basic water solvent used is 0 parts by weight of DIPN.
．． It ranges from 1 to 10 parts by weight, preferably from 0-3 to 5 parts by weight. If it is less than 0.1 part by weight, the oxidation reaction will not proceed sufficiently, and if it is used in excess of 10 parts by weight, the effect will not change and the amount of basic waste liquid will increase, which is not preferable.

(Aromatic heterocyclic compounds) Aromatic heterocyclic compounds containing a nitrogen atom as a heteroatom used as an additive include i1) Although there are no particular limitations, examples include pyridine-9-virol, quinoline, etc., which have one nitrogen atom in the molecule. Aromatic heterocyclic compounds and derivatives thereof containing two nitrogen atoms in the molecule, such as pyrazine, pyridazine, pyrimidine, pyrazole, and quinazoline, 1.3.5- or 1.2. 4
Examples include aromatic heterocyclic compounds containing three nitrogen atoms in the molecule, such as -1-riazine and 1,2,4-triazole, and derivatives thereof. These can be used either alone or as a mixture of two or more in any proportion.

The amount of these nitrogen-containing aromatic heterocyclic compounds used is based on the raw material (
7) For DIPNf7+, 0. [ll ~100 moJ
L,% is preferably in the range from 0.1 to 70 mol%, particularly preferably from 1 to 50 mol%. If it is less than 0.1 mol %, the effect of addition will not be exhibited, and even if 1 (10 mol % or more) is used, the effect will not change.

(Surfactant) In the method of the present invention, a surfactant may be added to carry out the reaction if necessary. When adding a surfactant, the surfactant! Class 4 is not particularly limited and includes, for example, fatty acid soaps, alkyl sulfone #salts, sulfonates of alkylbenzenes and alkylnaphthalenes, alkyleftyl sulfonates, alkyl phosphates, alkyl ether phosphates, and the like. These may be used alone or in combination of two or more in any proportion.

If a surfactant is used, the amount used should be the same as the raw material DrP.
N 0.001 to 5% by weight, preferably 0.01 to 5% by weight
It is in the range of 2% by weight.

(Molecular Oxygen) As the molecular oxygen used for oxidation, oxygen gas or air is preferable. When using oxygen gas, it may be diluted to an arbitrary concentration with an inert gas such as nitrogen, argon, or helium.

(Radical Reaction Initiator) During the oxidation reaction, a radical reaction initiator can be used to shorten the induction period of the reaction.

Specific examples of the radical reaction initiator include 2.2-azobisisobutyronitrile, 1.1°-azobis(cyclohexane-1-carbonitrile), cumene hydroperoxide, and tert-butyl hydroperoxide. It will be done. Furthermore, an oxidation reaction product containing a hydroperoxide group obtained by the oxidation reaction of DIPN can also be used as a reaction initiator.

The amount of radical reaction initiator used is 0 relative to the raw material DIPN.
．． In the oxidation reaction, DIPN, an aromatic heterocyclic compound containing nitrogen as a heteroatom, a surfactant, and a radical reaction initiator are added to the basic aqueous solvent, and the mixture is stirred. This is done by supplying molecular oxygen at the same time.

Reaction temperature is 60-150°C, preferably 80-130°C
is within the range of If the temperature is lower than 60°C, the reaction rate becomes extremely slow, and if the temperature is higher than 150°C, the decomposition of the hydroperoxide group is significantly accelerated.
Preferably, the reaction is carried out under a pressure of .

The reaction time varies depending on conditions such as the number of reaction sites and the presence or absence of a radical reaction initiator, but is usually 4 to 48 hours.

(oxidation product) What is the oxidation product obtained by this oxidation reaction?

The main component is DHP, 2-(2-hydroxyisopropyl i 6-+2-hydroperoxyisopropyl)naphthalene (hereinafter abbreviated as HHP), OCA,
1,21
It is a mixture containing 2-hydroxyisopropyl)-6-itubrobylnaphthalene (hereinafter abbreviated as MCA) and the like.

The above oxidation reaction product is filtered, then dissolved in an organic heating medium and decomposed with an acid catalyst and hydrogen peroxide to produce DH.
Get N.

(I solvent) Examples of the Ia solvent for dissolving the oxidation reaction product include acetone, ketones such as methyl isobutyl ketone and methyl ethyl ketone, lower alcohols such as methanol and ethanol, and diethyl ether.

Ethers such as diisopropyl ether and tetrahydrofuran, carboxylic acids such as acetic acid and propionic acid, aromatic hydrocarbons such as benzene, toluene, and xylene,
Examples include aliphatic hydrocarbons such as hexane, heptane, and isooctane, and alicyclic hydrocarbons f4m such as cyclopentane and cyclohexane. These can be used alone or in a mixture of two or more in any proportion.

(#Catalyst) Examples of acid catalysts include inorganic acids such as sulfuric acid, hydrochloric acid, nitric acid, and phosphoric acid; monoacids such as trichloroacetic acid, p-toluenesulfonic acid, p-phenolsulfonic acid, and oxalic acid;
Examples include heteropolyacids such as phosphomolybdic acid and phosphotungstic acid, strongly acidic ion exchange resins, and solid acids such as active clay, silica alumina, and zeolite.

The amount of acid catalyst used is 0.1 to 20% relative to the oxidation reaction product.
% by weight.

(Hydrogen peroxide) Hydrogen peroxide is one of the oxidation reaction products mentioned above.
It is used to oxidize CA to DHP and increase the reserve of DHN. Further, it is preferable to use hydrogen peroxide because it significantly suppresses the dehydration condensation reaction of carbinol neck.

As hydrogen peroxide, in addition to hydrogen peroxide and its aqueous solution, 1
Substance that generates hydrogen peroxide under M decomposition reaction conditions 1 For example, sodium peroxide, calcium peroxide, etc. can also be used, but it is preferable to use hydrogen peroxide 6 The concentration of hydrogen peroxide is preferably 5 to 70%. .

The amount of hydrogen peroxide used is 1 per mole of 2-hydroxyisopropyl group that HIP, DCA, MCA, etc. have.
~2 mol, preferably 1-1.5 mol.

(Acid Decomposition Reaction) The acid decomposition reaction is carried out by reacting an organic solvent in which the #ized reaction product is dissolved with hydrogen peroxide in the presence of an acid catalyst q.

The reaction temperature is IO~12 (1℃, preferably 20~100℃)
℃ range.

The reaction time depends on the reaction temperature, but is usually 0.5 to 12 hours.
Preferably it is in the range of 1 to 8 hours.

After completion of the reaction, a base is added to the reaction product solution to neutralize the acid catalyst, and the aqueous layer is separated. The organic solvent is recovered from one organic layer to obtain the product.

C Example 1 The present invention will be specifically explained below with reference to Examples and Comparative Examples.

All yields in the text are expressed as mole % based on DIPN as the starting material.

In addition, analysis and quantification were performed using high performance liquid chromatography.

Example 1 In a 501 Hastelloy B autoclave, DIPN 5-
0g (2:1.5 mmol), 15-0g of 02 Toko % sodium hydroxide aqueous solution, 0.13g of pyridine
(1,59 mmol), Nonsal LN-1 (1,59 mmol), a mixture of aliphatic carboxylic acid sodium salts as surfactant (
0.025 g of NOF ■Product name) was charged.

Oxygen was introduced at a gauge pressure of 2 kg/cm'', and the oxidation reaction was carried out at a reaction temperature of 100°C with stirring at 150 Orpm.
(2) The reaction was carried out for 2 hours.

1) The conversion rate of 1PN was 98.3%, and the yield of ROHP was 35.4%. The yield of HHP was 27.4%, O
The yield of CA is 6.8%, DHP+HHP+DC
The selectivity of DI(P) in A was 50.8%.The yields of MHP and MCA were 13.9% and 7.7%, respectively.
It was 9%.

5.9 g of the oxidation reaction product obtained by filtering, washing with water, and drying the oxidation reaction mixture was dissolved in 20 g of acetone, and 1.56 g (13.8 mmol) of 30% hydrogen peroxide solution was added to obtain homogeneous acetone. It was made into dissolved MA. The amount of hydrogen peroxide used was 12 moles per 2-hydroxyisobu-a-vir group in the oxidation reaction product.

3 g of acetone was charged into a 100IIj four-eye flask equipped with a reflux condenser and a thermometer, and heated to 50°C. 9
Acetone solution B was prepared by dissolving 0.30% of 7% sulfuric acid in 5 g of acetone. Use separate pumps for acetone soluble aA and acetone Nagisa MB.

Continuously fed into the flask. Both supplies are 1.5
The reaction was completed in a few minutes, and the reaction was continued for an additional 1.5 hours.

A 5% aqueous sodium hydroxide solution was added to the reaction solution to adjust the pH to 6, and the aqueous layer was separated. Acetone was recovered from the 6 organic layers to obtain 3.9 g of a brown solid. This includes 2.62
g of DHN was included. DHP, HHP,
The conversion rate of D-CA was 100% in all cases, and the yield of DIN was 69.6%.

Comparative Example 1 An oxidation reaction was carried out for 18 hours in the same manner as in Example 1 except that pyridine was not added.

The conversion rate of DIPN was 89.9%, and the DHP yield was 25.9%.
7%, old (P yield was 212%, DCA yield was 6.2%, and the DHP selectivity of these total was 48.4%, MHP was 18.0%, MCA was I: The amount was 1.1%.

The oxidation reaction mixture was filtered, washed with water, and dried, and the amount of 30% hydrogen peroxide solution used was 1.06 g + 1). The acid decomposition reaction was carried out under exactly the same conditions as in Example I, except that the concentration was 0 mmol).

The amount of hydrogen peroxide used was 12 molar equivalents relative to the 2-hydroxyisopropyl group in the oxidation reaction product.

As a result, 4.2 g of a brown solid was obtained. This includes 2.
It contained 00g of DHN. [lHP, HH
The conversion rates of P and DCA were both 100%, and the yield of DIN was 53.1%.

[Effect of the invention 1] According to the method of the present invention, by adding an aromatic heterocyclic compound containing a nitrogen atom as a heteroatom in the oxidation reaction of DIPN, the conversion rate of DIPN is significantly improved,
Among the reaction products, the yield of DHP + HHP + OCA is improved and the selectivity is high, so the amount of hydrogen peroxide used in the next acid decomposition reaction is small and the desired DHN can be obtained in high yield 1) This method is suitable as a detailed method.

Claims (1)

[Claims] (1) In the method for producing 2,6-dihydroxynaphthalene, in which 2,6-diisopropylnaphthalene is oxidized with molecular oxygen and the resulting product is decomposed with acid, the oxidation reaction involves a nitrogen atom as a heteroatom in the molecule. 1. A method for producing 2,6-dihydroxynaphthalene, which is carried out in the presence of an aromatic heterocyclic compound.