JPH03109342A - Production of 4,4'-dihydroxydiphenylmethane - Google Patents

Abstract

PURPOSE:To obtain the subject compound useful as a raw material for epoxy resin, etc., from phenol and a formaldehyde source in improved yield by adding a crown ether to the reaction system, reacting under specific condition, acidifying the reaction liquid and reacting with phenol. CONSTITUTION:Phenol is made to react with a formaldehyde source in an alcoholic organic solvent (preferably ethanol, n-propanol, i-propanol, i-butanol, etc.) under basic condition with sodium hydroxide, etc., in the presence of a crown ether at 0-130 deg.C, preferably 30-80 deg.C. In the 2nd stage, the reaction liquid obtained in the former stage and containing p-hydroxybenzyl alcohol is acidified and made to react with phenol to obtain the objective compound. The acid for the acidification is e.g. hydrochloric acid or nitric acid. The amount of phenol is 5-25 pts. per 1 pt. of hydroxymethylphenol in the reaction system.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for producing dihydroxydiphenylmethane from phenol and formaldehyde, particularly in 4.
The present invention relates to a method for selectively producing 4-dihydroxydiphenylmethane.

Dihydroxydiphenylmethane obtained by reacting phenol and formaldehyde under acidic conditions is usually 2.2°
It is a mixture of three isomers: monolithic, 2.4′-isomer, and 4.4′-isomer.

Dihydroxydiphenylmethane, which is a mixture of these three isomers, is a compound useful as a raw material monomer for polymers such as a raw material for epoxy resins.

Furthermore, 4,4-dihydroxydiphenylmethane is a very interesting compound as it is known that its polymer is improved in terms of heat resistance and the like compared to conventional dihydroxydiphenylmethane mixtures.

[Prior art l] Conventionally, dihydroxydiphenylmethane has been industrially produced by coexisting formaldehyde and phenol (13 to 30 molar excess relative to aldehyde) in the presence of various acids without a solvent and heating and stirring the mixture ( For example, JP-A-55-
124730, etc.), the isomer ratio of dihydroxydiphenylmethane obtained in this way is 1, usually 15-25% of 2.2-unit, 40-45% of 2.4-unit, 4
．． Some examples of selective synthesis of 64.4°-dioxydiphenylmethane with 30 to 40% of 4' monomers have been proposed. When the reaction is carried out in the presence of monomethylurea as an additive, the 4.4'-isomer is obtained with a selectivity of 68 to 74%, and when monomethylurea is used as an additive, the 4.4'-isomer selectivity is the highest. It is stated that the ratio is 74% at best. According to Japanese Patent Publication No. 48-38694, when phenol and formalin are heated and stirred using an acid catalyst in the presence of a polar aprotic solvent, the
4.4 integrals are obtained with a selectivity of 82%.

However, in a system in which alkyl-substituted urea is added, the 5 selectivity is only 74%, and methylolated urea is produced as a by-product. In addition, in systems run under polar aprotic solvents, the solvent that provides high selectivity is diethylformamide (boiling point 176-177°C, selectivity 77%).
, dimethylformamide (boiling point 152°C, selectivity 82%
), etc., and are expensive as solvents, and both are impractical for industrial production methods.

[Problem to be Solved by the Invention 1] The purpose of the present invention is to provide a new method for selectively producing 4,4'-dihydroxydiphenylmethane, which is interesting as a raw material monomer for polymers under these circumstances. It is in.

[Means for Solving the Problems 1] When producing dihydroxydiphenylmethane, the present invention first selectively synthesizes parahydroxybenzyl alcohol, which is an intermediate of 4.4°-dihydroxydiphenylmethane, under basic conditions, and then reacts it. By making the system acidic using an acid, adding phenol as necessary and heating and stirring, we succeeded in synthesizing 4.4°-dihydroxydiphenylmethane with high selectivity.

That is, the present invention provides a method for producing dihydroxydiphenylmethane from phenol and a formaldehyde source, in which phenol and a formaldehyde source are reacted in an alcoholic organic solvent under basic conditions with the addition of crown ether to produce parahydroxybenzyl. This is a method for producing 4,4-dihydroxydiphenylmethane, which is characterized by producing alcohol, then acidifying the reaction solution, and further reacting with phenol.

In the present invention, formaldehyde sources to be reacted with phenol include formalin, paraformaldehyde, and lower alcohol hemiformal.

Examples include hemiformal, which is a polyhydric alcohol having 2 to 5 carbon atoms, and among them, paraformaldehyde is preferred.

Formalin may be used in small amounts, but as the water-containing layer in the reaction system increases, the rose selectivity decreases slightly.

In particular, when formaldehyde purified by sublimation from formaldehyde is used, the reaction proceeds quickly, side reactions are suppressed, and the reaction can be carried out in high yield.

■ Bases that create basic conditions include metal hydroxides such as sodium hydroxide and potassium hydroxide, metal alkoxides such as sodium methoxide, sodium ethoxide, and potassium tert-butoxide, and metal hydroxides such as sodium hydroxide. A metal-containing base with higher basicity than phenol, such as phenol, is used.

Examples of alcohol-based organic solvents used in alcohol 7, -2 and the method of the present invention include methanol, ethanol, n-propanol, i-propanol, and n-butanol.

i-butanol and alkyl alcohols having a carbon number of 10 or less, ethylene glycol,
Various alcohols such as polyhydric alcohols such as 2.3-butanediol, benzyl alcohol, and similar aromatic alcohols may be used alone or in combination. Among these, lower alcohols such as ethanol, n-propanol, i-propanol, and i-butanol are particularly preferred because of their high selectivity and fast reaction rate.

As the alcoholic organic solvent of the present invention, a non-alcoholic organic solvent can be mixed with these alcohols. Non-alcoholic solvents that can be mixed include aromatic solvents such as benzene, toluene, and xylene, aliphatic solvents such as pentane, hexane, and heptane, alkyl halides such as chloroform, dichloromethane, and dichloroethane, and dimethylacetamide. ,
Various organic solvents include amides such as dimethylformamide, sulfoxides such as dimethyl sulfoxide, and nitriles such as acetonitrile and benzonitrile.

The mixing ratio of the non-alcoholic heating medium is preferably 70% or less, and 7
If more than 0% is used, the reaction rate will be slow. Generally, it is preferable to use a solvent consisting of alcohol alone or in combination.

Crown ether In the method of the present invention, examples of crown ethers added as additives include 1, for example, 1B-crown ether-6.
, dibenzo-18-crown ether-6, dicyclohexano-18-crown ether-6, benzo-18-
So-called 18-crown ethers such as crown ether-6 and cyclohexanor 18-crown ether-6
Category 6, also equivalent to the above! 5-Crown Aether 5
Examples include crown ethers with various ring sizes such as 24-crown ether-8, and rice crown ethers having binaphthol or an aromatic group in the ring. Moreover, polymers containing the above-mentioned crown ethers are also included in the crown ethers referred to in the present invention.

Various methods are known for immobilizing crown ethers (for example, see Michio Hiraoka's "Crown Compounds").
- Addition-polymerized polymeric crown ether of dibenzo-18-crown-6 and aldehyde, polycondensation-type crown ether polymer of diaminobenzo-18-crown-6 and diacid chloride, diisocyanate, etc., as inside the shell; Polymers such as polyvinyl crown compounds have been synthesized.

Various acidic catalysts can be used as the acid used in the oxidation reaction, such as hydrochloric acid, sulfuric acid, phosphoric acid, &A acid, perchloric acid, para-toluenesulfonic acid, sulfone group type ion exchange resin, acid clay, silica alumina, etc. .

Reaction 12 (first stage reaction) The reaction is carried out by adding 0.1 to 10 moles of phenol, preferably 0.3 to 10 moles of phenol, to lβ, a single or mixed solvent consisting of the above-mentioned alcohol-based organic solvents, usually under a nitrogen atmosphere. 3 moles,
Formaldehyde to phenol, 0. 5 equivalents, preferably 0.1-1 equivalents of base, 0.1-10 equivalents, preferably 0.3-1.2 equivalents of base to phenol, and 0.1-10 equivalents of crown ether to base, Preferably, 0.8 to 5 equivalents are added to hydroxymethylate the phenol first.

The reaction temperature is in the range of 0 to 130°C, preferably 30 to 80°C. The reaction time depends on the reaction temperature and the solvent used, for example, when the reaction temperature is 60°C, the reaction time is usually 6 to 24 hours. Although the 6-hydroxymethylation reaction has higher rose selectivity at lower temperatures, the reaction rate decreases accordingly.

The reaction ends when formaldehyde is no longer present, and the reaction system is returned to room temperature.

(Second stage reaction) Next, add the above acid to the reaction system which has returned to room temperature to neutralize the base in the reaction system, and add excess acid, preferably 0.3~
Adjust so that 20 mol% acid is present. In addition, phenol is 3
Phenol is added as necessary to increase the amount by 50 times, preferably 6 to 25 times.

The first stage reaction product prepared in this way was heated to room temperature to J20°C.
4.4°-dihydroxydiphenylmethane is obtained by heating and stirring, preferably at 60 to 90° C. under a nitrogen atmosphere. The time required for the second stage reaction is 1 to 10 hours.

After the reaction is completed, the reaction solution is returned to room temperature, washed with water, the organic layer is separated, and unreacted phenol and solvent are removed by distillation or other methods to obtain 4,4'-dihydroxydiphenylmethane. If it is necessary to further increase the purity, recrystallization is performed using aromatic hydrocarbons such as toluene, ethylbenzene, and xylene.

〔Example】

Hereinafter, the present invention will be described in detail based on Examples, but the present invention is not limited to these Examples, and may have various embodiments.

Example 1 5 ml of isopropyl alcohol and 0.544 g of phenol (5,7
8 mmol), sodium hydroxide 0.242g + 5.7
8 mmol) and 1.5 I8-crown-6-ether
After adding 33 g (5.78 mmol) and purging with nitrogen, the mixture was heated to 80° C. and stirred. After confirming that the contents had melted, the temperature was returned to room temperature.

A pure hemiformal isopropyl alcohol solution with a concentration of 0.67 mol/I2 in which sublimated rose formaldehyde is dissolved in isopropyl alcohol. 0.86 ta
l (0.578 mmol formaldehyde) was added,
The atmosphere was again purged with nitrogen, and the mixture was heated and stirred at 50° C. for 24 hours to obtain a first-stage reaction product.

Analysis of the products in the reaction solution by liquid chromatography revealed that there were two types of products: barahydroxybenzyl alcohol and orthohydroxybenzyl alcohol, and the selectivity of barahydroxybenzyl alcohol was 88.3%, indicating that formaldehyde conversion The yield was 100% and the yield based on formaldehyde was 85.6%.

12N-1icj was added to this reaction mixture to adjust the amount of acid to be 0.05 mmol in excess. After purging this acidic liquid with nitrogen, it was heated to 80°C and stirred for 4 hours.

When the reaction mixture was cooled to room temperature and analyzed, no hydroxybenzyl alcohol was found in the reaction mixture, and the product was 4,4-dihydroxydiphenylmethane, 2.4'
-dihydroxydiphenylmethane, 2.2-dihydroxydiphenylmethane and some polynuclear bodies, the content of 4.4 units in the dihydroxydiphenylmethane mixture is 80.
2%, 2.4° integral was 19.8%, and 2.2 integral was 0.1%.

Comparative example! 5sj of isopropyl alcohol and 0.515g of phenol in a 15ml closed pressure glass reactor 15.47
mmol) and sodium hydroxide 0.230 g (5,
After purging with nitrogen, the mixture was heated and stirred at 80°C, and after confirming that the contents had melted, the temperature was returned to room temperature.

Pure hemiformal isobrobyl alcohol 0.82 Peng I (formaldehyde 0.547 mmol) with a concentration of 0.67 mol/β was added, and the mixture was purged with nitrogen again and heated at 50°C. The mixture was heated and stirred for 9 hours. When this reaction mixture was returned to room temperature and analyzed by liquid chromatography, it was found that there were two types of products, parahydroxybenzyl alcohol and orthohydroxybenzyl alcohol, and the selectivity for parahydroxybenzyl alcohol was 40.3%.

Next, 12N-HGi was added to this reaction solution, adjusted to have an excess of 0.05 mol of acid, and the mixture was replaced with nitrogen.
The mixture was heated and stirred at 0°C for 4 hours.

When the reaction solution was returned to room temperature and analyzed, no hydroxybenzyl alcohol was found in the reaction solution, and the product was
4.4'-dihydroxydiphenylmethane, 2.4-
They were dihydroxydiphenylmethane, 2.2'-dihydroxydiphenylmethane, and some polynuclear substances. The content of 4.4 in the dihydroxydiphenylmethane mixture was 36.1%.

2.4゛ one-piece 57.7%, 2,2゛ one-piece 6.2%
Met.

Example 2 In a 15 ml closed pressure glass reactor, 5 sl of isopropyl alcohol, 0.497 g phenol (0.497 g + 5.28 mmol), 0.222 g (5.28 mmol) sodium hydroxide and 1.840 g 18-crown-6-ether
g! After purging with nitrogen, the mixture was heated and stirred at 80°C, and after confirming that the contents had melted, the temperature was returned to the original temperature in the chamber.

The concentration of rose formaldehyde purified by sublimation dissolved in isopropyl alcohol is 0.67 mol/! Pure hemiformal isopropyl alcohol solution 1.58a+1
(Formaldehyde!, 06 mmol) was added, the atmosphere was replaced with nitrogen again, and the mixture was heated and stirred at 40° C. for 92 hours to complete the first stage reaction.

The products in the reaction solution are three types: parahydroxybenzyl alcohol, orthohydroxybenzyl alcohol, and dimethylolphenol. The ratio of parahydroxybenzyl alcohol among the three types is 86.1%, and the paraselectivity in monomethylolation is 88. .1%, and the formaldehyde conversion rate was 100%.

This reaction mixture was added with 0.992 g of phenol (10,54
mmol), 12N-11c10.45+++11
After adding 5.40 mmol) and purging with nitrogen, the reaction solution was heated and stirred at 60°C for 7 hours. When the reaction solution was returned to room temperature and analyzed, no hydroxybenzyl alcohol was observed in the reaction solution, and the product was 4.40 mmol). 4°-dihydroxydiphenylmethane, 2.4-dihydroxydiphenylmethane.

2.2'-dihydroxydiphenylmethane and some polynuclear substances containing three or more aromatic rings, the selectivity of dihydroxydiphenylmethane is 92.3%, and the isomer ratio of dihydroxydiphenylmethane is 4.4' and 81' ．．
1%, 2.4 body is 17.3%, 2.2°-body is 1
．． [Effect of the invention 1] The present invention is a method for synthesizing dihydroxydiphenylmethane from phenol and formaldehyde, in which an alcoholic organic solvent is used under basic conditions and a crown ether is added as the first step reaction. Through the process of selectively synthesizing parahydroxybenzyl alcohol, it was possible to selectively produce 4.4° monomer.

The present invention is a novel method for producing 4,4-dihydroxydiphenylmethane, whereby 4,4'-dihydroxydiphenylmethane can be obtained in high yield.

Claims (1)

[Claims] (1) In a method for producing dihydroxydiphenylmethane from phenol and a formaldehyde source, phenol and a formaldehyde source are reacted in an alcoholic organic solvent under basic conditions with the addition of crown ether to produce parahydroxybenzyl alcohol. A method for producing 4,4'-dihydroxydiphenylmethane, which is characterized in that the reaction solution is acidified, and further phenol is reacted.