JPH03240745A - Production of 4,4'-dihydroxybiphenyl - Google Patents

Abstract

PURPOSE:To obtain the title compound derived from a specific intermediate of enhanced selectivity by oxidation of 4,4'-diisopropylbiphenyl with molecular oxygen in the presence of a compound having primary amino group followed by acid decomposition. CONSTITUTION:When the objective 4,4'-dihydroxybiphenyl useful as a raw material for polymers of liquid crystal nature or heat-resistant resins is to be produced by oxidation of 4,4'-diisopropylbiphenyl followed by acid decomposition of the resulting product, the oxidation reaction is performed in the presence of 0.01-100 (pref. 0.1-70)mol%, based on the raw material, of a compound having in the molecule primary amino group such as n-hexylamine, glycine or ethylenediamine, whereby enhancing the selectivity of DHP (one of the oxidation products given in the table) leading to the objective compound through the acid decomposition and reducing the amount of the hydrogen peroxide to be used in said acid decomposition, thus obtaining the objective compound in high yield and in an industrially advantageous manner.

Description

Detailed Description of the Invention [Industrial Field of Application 1] The present invention relates to a method for producing 4.4'-dihydroxybiphenyl (hereinafter abbreviated as BPL), particularly 4.4°
The present invention relates to a method for producing BPL, in which diisopropylbiphenyl (hereinafter abbreviated as DIPBP) is oxidized with molecular oxygen and the obtained peroxide is decomposed with acid. BPL, which is the object of the present invention, is a compound useful as a raw material for liquid crystalline polymers, heat-resistant resins, and the like. [Prior Art] Conventional methods for producing BPL include a method in which 2,6-di-tert-butylphenol is oxidatively coupled and the resulting diphenoquinone is reduced and debutylated, and a method in which biphenyl is sulfonated and alkali-fused. However, there were problems as an industrial production method, such as the production process being complicated and a large amount of inorganic salts being produced as by-products. On the other hand, there is a method in which dialkylbenzenes are oxidized with molecular oxygen to form the corresponding dihydroperoxides, which are then decomposed with acid to obtain phenols. (Japanese Unexamined Patent Publication No. 48-72144), and a method of producing 2,6-dihydroxynaphthalene from 2,6-diitubrobylnaphthalene via 2,6-diitubropylnaphthalene dihydroberoxide. (Unexamined Japanese Patent Publication No. 61-93156)
etc. are known. As an example of applying this method to DIPBP,
-75440 publication discloses that DIPBP is oxidized to give 4.4
°-Diisopropylbiphenyl dihydroperoxide (
(hereinafter abbreviated as DHP), which is decomposed with acid to produce BP.
A method for obtaining L is disclosed. [Problem to be Solved by the Invention J] In the method described in JP-A-64-75440, substances shown in the following table are produced as oxidation products in addition to HP. Table Among these products, 4-(2-hydroxyisopropyl)-4°-(2-hydroperoxyisopropyl)
Biphenyl (abbreviated as HHP in the table above) and 4,4'-bis(2-hydroxyisopropyl>biphenyl (abbreviated as CA in the table above)) do not produce BPL when they are directly decomposed with acid, but are dehydration products. To produce 4-(4-impropenylphenyl)phenol and 4,4-diisopropenylbiphenyl, HHP can be produced by acid decomposition in the coexistence of at least 1 mole of hydrogen peroxide per mole of 2-hydroxyisopropyl group. However, in order to increase the yield of BPL, this method increases the conversion rate from DIPBP to DHP + HHP + DCA by extending the reaction time, increasing the amount of alkali, etc. The proportion of DHP among them decreases and H
The percentage of HP and OCA increases. In particular, 4-(2-hydroperoxyisopropyl)-4°-isopropylbiphenyl (abbreviated as Ml (P) in the above table), 4-(2-hydroxyisopropyl)-4°-isopropylbiphenyl (
When the reaction is carried out until the proportion of substances containing unreacted isopropyl groups such as MCA (abbreviated as MCA in the table above) and unreacted DIPBP is 10% or less, the generated DHP+HHP+
There is a problem in that the proportion of DHP in DCA is 35% or less, and the amount of hydrogen peroxide added during acid decomposition increases by the amount of 2-hydroxyisopropyl groups. The purpose of the present invention is to provide an industrially advantageous method for producing PL that increases the selectivity of DHP in the above oxidation reaction, uses less hydrogen peroxide during acid decomposition, and has a high yield of BPL. There is a particular thing. [Means for Solving the Invention] The present invention provides DHPBP by adding a compound having a primary amino group in the molecule during the oxidation reaction of DIPBP.
This method solves the above problems by increasing the selectivity of That is, the present invention provides a method for producing BPL in which DIPBP is oxidized with molecular oxygen and the resulting product is decomposed with acid, and the oxidation reaction is carried out in the presence of a compound having a primary amino group in the molecule. This is a method for manufacturing BPL characterized by the following. The oxidation reaction of DIPBP with molecular oxygen is generally carried out in a basic aqueous solvent. The basic compound used is preferably an alkali metal compound, 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 bicarbonate and potassium bicarbonate; alkali metal phosphates such as sodium phosphate, potassium phosphate, sodium hydrogen phosphate, potassium hydrogen phosphate, sodium dihydrogen phosphate, and potassium dihydrogen phosphate; salts, and alkali metal boron compounds such as sodium tetraborate. These can be used alone or in a mixture of two or more in any proportion. The concentration of these alkali metal compounds in water solvent is 30%
The following are preferred. The amount of the basic aqueous solvent to be used is sufficient as long as it keeps the pH of the reaction mixture at 8 or more, and specifically, it is 0.1-10 parts by weight, preferably 0.3-5 parts by weight per 1 part of DIPBP. Parts by weight range. 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. Examples of compounds having a primary amino group in the molecule used as additives include methylamine, ethylamine, 0-propylamine, isopropylamine, n-butylamine, nibutylamine, tertiary-butylamine, n-
Aliphatic amines such as hexylamine, n-decylamine, ethylenediamine, 1,2-diaminopropane, 1,3-diaminopropane, and ethanolamine, amino acids such as glycine, alanine, serine, lysine, and glutamic acid, aniline, o- , rrr-, p-toluidine and other aromatic amines, and benzylamine and other aralkylamines. These can be used alone or in a mixture of 6 or more types in any proportion. The amount of the compound having a primary amino group in the molecule is in the range of 0.01 to 100 mol%, preferably 0.1 to 70 mol%, particularly preferably 1 to 50 mol%, based on the raw material DIPBP. be. If it is less than 0.01 mol%, the effect of addition will not be exhibited, and even if it is used at 100 mol% or more, the effect will not change. In the method of the present invention, a surfactant may be added to carry out the reaction if necessary. When adding a surfactant, there is no particular restriction on the type of surfactant, such as fatty acid soap,
Examples include alkyl sulfonates, alkylbenzene sulfonates, alkylnaphthalene sulfonates, alkyl ether sulfonates, alkyl phosphates, and alkyl ether phosphates. 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 determined by the DIP of the raw material.
0.001 to 5% by weight based on BP, preferably 0.01 to 5% by weight
It is in the range of 2% by weight. As the molecular oxygen used for oxidation, oxygen gas or air is preferable. When oxygen gas is used, it may be diluted to an arbitrary concentration with an inert gas such as nitrogen, argon, or helium. During the oxidation reaction, a radical reaction initiator is preferably used in order 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. Further, an oxidation reaction product containing a hydroperoxide group obtained by the oxidation reaction of DIPBP can also be used as a radical reaction initiator. The amount of the radical reaction initiator used is in the range of o, oos to 20% by weight based on the raw material DIPBP.The oxidation reaction is performed by adding DIPBP to the basic aqueous solvent, using a compound having a primary amino group in the molecule, and using a radical reaction initiator. This is done by adding an initiator and, if necessary, a surfactant, and supplying molecular oxygen while stirring. 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 will be extremely slow, and if the temperature is higher than 150°C, the decomposition of the hydroperoxide group will be significantly accelerated, which is not preferred. The pressure during the reaction may be normal pressure or elevated pressure, but the pressure may be from normal pressure to 10
It is preferable to carry out the reaction under a pressure of kg/cm"G. The reaction time varies depending on conditions such as the reaction temperature and the presence or absence of a radical reaction initiator, but is usually 4 to 48 hours. The oxidation products include DHP as the main component, and HHP, OCA, and MH as byproducts.
It is a mixture containing P, MCA, etc. Cellulose Reaction The above oxidation reaction product is collected by filtration, then dissolved in an organic solvent, and subjected to acid decomposition using an acid catalyst and hydrogen peroxide to obtain BPL. Examples of organic solvents that dissolve oxidation reaction products include ketones such as acetone, methyl isobutyl ketone, and methyl ethyl ketone, lower alcohols such as methanol and ethanol, ethers such as diethyl ether, diisopropyl ether, and tetrahydrofuran, acetic acid, and propion. Carboxylic acids such as acids, nitriles such as acetonitrile, aromatic hydrocarbons such as benzene, toluene, and xylene, alicyclic hydrocarbons such as hexane, heptane, and isooctane, and alicyclic hydrocarbons such as cyclopentane and cyclohexane. There are various types. These can be used alone or in a mixture of 6 or more types in any ratio. Examples of acid catalysts include inorganic acids such as sulfuric acid, hydrochloric acid, nitric acid, and phosphoric acid, organic acids such as trichloroacetic acid, p-toluenesulfonic acid, p-phenolsulfonic acid, and oxalic acid, and phosphomolybdic acid and phosphotungstic acid. Examples include solid acids such as telopolyacid, strongly acidic ion exchange resins, activated clay, silica alumina, and zeolite. The amount of acid catalyst used is 0.01 to 2% relative to the oxidation reaction product.
It is in the range of 0% by weight. Hydrogen peroxide is used to convert HHP and OCA among the oxidation reaction products into DHPC and increase the yield of BPL. Further, it is preferable to use hydrogen peroxide because it significantly suppresses the dehydration condensation reaction of carbinols. As hydrogen peroxide, in addition to hydrogen peroxide and its aqueous solution,
Substances that generate hydrogen peroxide under acid decomposition reaction conditions, such as sodium peroxide and calcium peroxide, can also be used, but it is preferable to use an aqueous hydrogen peroxide solution, with a hydrogen peroxide concentration of 5 to 70%. preferable. The amount of hydrogen peroxide used is 1 per mole of 2-hydroxyisopropyl group possessed by HHP, DCA, MCA, etc.
~2 mol, preferably l-1.5 mol. The acid decomposition reaction is carried out by bringing an organic solvent in which the oxidation reaction product is dissolved and hydrogen peroxide into contact in the presence of an acid catalyst and heating the mixture. Reaction temperature is 10-120°C, preferably 20-100°C
is within the range of The reaction time depends on the reaction temperature, but is usually in the range of 0.5 to 12 hours, preferably 1 to 8 hours. After the reaction is completed, 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. [Example 1] Hereinafter, the present invention will be explained in more detail with reference to Examples and Comparative Examples. All yields in the text are expressed in mol % based on the raw material DIPBP, that is, as follows. Analysis and quantification were performed by high performance liquid chromatography. In addition, the radical reaction initiator used in the oxidation reaction in the following Examples and Comparative Examples was an oxidation reaction product having a 2-hydroperoxyisoprobyl group obtained by the following method. (Preparation of radical reaction initiator) DIPB in a 50 mj/steroid B autoclave
Plo, 0 g 141.9 mmol), 4.5% by weight aqueous sodium hydroxide solution 10. og and 0.01 g of 1.1'-asobis(cyclohexane-1-carbonitrile) as a radical reaction initiator, and oxygen was introduced until the gauge pressure reached 2 kg/c1. 100℃, 150
While stirring at 0 rpm, oxygen was continuously supplied so that the internal pressure was maintained at 2 kg/c+w"G, and the reaction was carried out for 22 hours. The sodium hydroxide aqueous solution was removed from the reaction mixture, and the pH of the washing solution was adjusted to 7. The obtained solid was dried to obtain 11.2 g of a white powdery solid. This solid was used as a radical reaction initiator for the oxidation reaction in the following Examples etc. Its composition was as follows. DHP 16.8%, HHP 3B, 1%
, DCA20.6%, HHP8.8%, MCA3.7
%, DIPBP O, 9%, and others 6.1%. Example 1 In a 50 mj Hastelloy 8 autoclave, DIPBP
5.0g (21.0 mmol), 0.5% by weight aqueous sodium hydroxide solution 15.0g, n-hexylamine 0
．． 10 g (1,0 mmol) of Nonsal LN, a mixture of aliphatic carboxylic acid sodium salts as surfactant
-1 (NOF■Product name) 0.025g and 0.050g of the oxidation reaction product containing the 2-hydroperoxyisoprobyl group prepared in advance as a radical reaction initiator
I prepared g. Oxygen was introduced at a gauge pressure of 2 kg/cm2, and an oxidation reaction was carried out at a reaction temperature of 100° C. and stirring at 150 rpm. Oxygen was continuously introduced so that the pressure of the reaction system was maintained at 2 kg/cm"G. Eight hours after the start of the reaction, 0.1 Oa of n-hexylamine was added.
11. Romilimol) was added and the reaction was continued for an additional 8 hours. The conversion rate of DIPBP was 99% and the yield of DHP was 43.3.
%Met. The yield of HIP was 33.4%, the yield of OCA was 7.3%, and the DH in DHP+HHP+DCA was
The selectivity of P was 51.5%. Also, MHP,
The yields of MCA were 6.3% and 2.7%, respectively. 6.3 g of the oxidation reaction product obtained by filtering the oxidation reaction mixture, washing with water, and drying was dissolved in 20 g of acetone to give a solution of 30%
A homogeneous acetone solution A was prepared by adding 1.5 g (13.2 mmol) of hydrogen peroxide. The amount of hydrogen peroxide used is 1
! The molar equivalent was 1.2 with respect to the 2-hydroxyisopropyl group in the product of the I-formation reaction. 3 g of acetone was charged into a 100 mj four-eye flask equipped with a reflux condenser and a thermometer, and heated to 50°C. 97
Acetone solution B was prepared by dissolving 0.31 g of % sulfuric acid in 5 g of acetone. Acetone solution A and acetone solution B were continuously supplied into the flask using separate pumps. All feedings were completed in 1.5 hours, and the molds were then allowed to react for 1.5 hours. Add 5% aqueous sodium hydroxide solution to the reaction solution to prepare p)I.
6 and the aqueous layer was separated. When acetone was recovered from the organic layer, 4.0 g of a slightly yellow solid was obtained. There are 3
．． Contained 40g of BPL. DHP. )1) The conversion rates of IP and OCA were both 100%, and the yield of BPL was 84%. Example 2 In place of n-hexylamine, glycine was initially added to 0,1
Og (1,33nuaoll, 0.10 after 8 hours
The oxidation reaction was carried out for 16 hours in exactly the same manner as in Example 1, except that 1.5 g of the oxidation reaction solution was added. The conversion rate of DIPBP was 99.6%, and the yield of DHP was 39%.
．． 3%, HIP yield 37.5%, DCA yield 6.2%, and the DHP selectivity in these total is 47.3%,
7.1% of HHP and 3.2% of MCA were produced as by-products. The oxidation reaction mixture was filtered, washed with water, and dried, and the acid decomposition reaction was carried out under exactly the same conditions as in Example 1, except that the amount of 30% hydrogen peroxide solution used was 1.5 g. The amount of hydrogen peroxide used was 1.2 molar equivalent relative to the 2-hydroxyisopropyl group in the oxidation reaction product. As a result, 4.05 g of a slightly yellow solid was obtained. This contained 3.24g of BPL. DHP, H
The conversion rates of HP and DCA were both 100%, and the yield of BPL was 83%. Example 3 An oxidation reaction was carried out for 16 hours in exactly the same manner as in Example 1, except that ethylenediamine was used instead of n-hexylamine, and 0.1 Og (1 mmol) was added initially and no additional addition was made. Ta. The conversion rate of DIPBP was 99.7% and the yield of DHP was 28%.
．． 3%, HHP yield 41.2%, DCA yield 15.0%
The DHP selectivity of the total was 33.5%, with 5.7% of HHP and 3.9% of MCA occurring as by-products. An acid decomposition reaction was carried out under exactly the same conditions as in Example 1, except that the oxidation reaction mixture was filtered, washed with water, and dried, and the amount of 30% hydrogen peroxide used was 2.1 g. The amount of hydrogen peroxide used was 1.2 molar equivalent relative to the 2-hydroxyisopropyl group in the product of the aI reaction. As a result, 4.1 Og of a slightly yellow solid was obtained. This contained 3.24g of BPL. DHP, H
The conversion rates of HP and OCA were both 100%, and the yield of BPL was 84.5%. Comparative Example 1 An oxidation reaction was carried out for 16 hours in the same manner as in Example 1, except that n-hexylamine was not added and 5.0% by weight aqueous sodium hydroxide solution 0.2+sj was added every 2 hours. . The conversion rate of DIPBP was 98.6%, the yield of DHP was 42.5%, the yield of HHP was 24.7%, and the yield of DCA was 3.8%.
%, the total DHP selectivity was 59.8%, but 68% of 1M essential and 4.4% of MCA were produced as secondary products. The oxidation reaction mixture was filtered, washed with water, and dried, and the acid decomposition reaction was carried out under exactly the same conditions as in Example 1, except that the amount of 30% hydrogen peroxide used was 1.01%. The amount of hydrogen peroxide used was 1.2 molar equivalent relative to the 2-hydroxyisopropyl group in the oxidation reaction product. As a result, 3.97 g of a slightly yellow solid was obtained. This contained 2.78g of BPL. DHP,
HHP. The addition rate of DCA was 100% in all cases, and the yield of BPL was 71%. Comparative Example 2 Without adding n-hexylamine and surfactant, 0.5
4.5% by weight instead of aqueous sodium hydroxide solution
The oxidation reaction was carried out continuously for 42 hours in the same manner as in Example 1 except that 10 g of aqueous sodium hydroxide solution was used. The conversion rate of DIPBP is 99.8% and the yield of 1DHP is. 9.9%, HHP yield 40.8%, DCA yield 34.5
%, and the DHP selectivity in these totals was 11.6%, with 2.7% MnF and 6.0% MCA occurring as by-products. The oxidation reaction mixture was filtered, washed with water, and dried, except that the amount of 30% hydrogen peroxide used was increased from 1.5 g to 3.3 g.
The acid decomposition reaction was carried out under exactly the same conditions as in Example 1. The amount of hydrogen peroxide used was 1.2 molar equivalent to the 2-hydroxyisopropyl group in the oxidation reaction product. As a result, 4.15 g of a slightly yellow solid was obtained. This contained 3.32g of BPL. DHP, H
HP. The addition rate of DCA was 100% in all cases, and the yield of BPL was 85%. [Effect of the invention 1] According to the method of the present invention, in the oxidation reaction of orpep, by adding a compound having a primary amino group in the molecule, the DHP selectivity can be increased, and as a result, the following Since the amount of hydrogen peroxide used in the acid decomposition reaction is small, it is suitable as an industrial method.

Claims (1)

[Claims] (1) Oxidizing 4,4'-diisopropylbiphenyl with molecular oxygen and acid decomposing the resulting product 4,4-
A method for producing 4,4'-dihydroxybiphenyl, characterized in that the oxidation reaction is carried out in the presence of a compound having a primary amino group in the molecule.