JPS6130544A - Preparation of 1,3,5-trialkyl-2,4,6-tris(3,5-dialkyl-4-hydroxybenzyl)benzene - Google Patents

Abstract

PURPOSE:To produce the titled compound useful as an antioxidant, from 2,6-dialkylphenol, etc., economically, in two steps, by carrying out the first-stage reaction while removing water from the reaction system, and using the obtained reaction mixture as the raw material for the second-stage reaction. CONSTITUTION:A mixture of 2,6-dialkylphenol, formaldehyde (or its polymer), a secondary amine and a carboxylic acid is heated and reacted with each other under heating while removing the produced water from the reaction system to obtain a reaction mixture containing 1-acyloxymethyl-3,5-dialkyl-4-hydroxybenzene. The obtained reaction mixture is made to react with 1,3,5-trialkylbenzene in the presence of an acid catalyst to obtain the objective 1,3,5-trialkyl-2,4,6-tris(3,5-dialkyl-4-hydroxybenzyl)benzene in high yield compared with conventional method. The process is economical because of the reduced consumption of the acid catalyst and the simplified production procedure.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of the Invention] The present invention relates to i,5.5-)realkyl-2,4,6-tris(5,5-dialkyl-4-hydroxybenzyl)
This invention relates to an improved method for producing benzene.

[Industrial application field]

t,5-trialkyl-2,4,6-)ris(5゜5-
Dialkyl-4-hydroxybenzyl)benzene is a compound useful as an antioxidant.

[Prior art]

1.5.5-) Real Kill-2,4,6-) Squirrel (5
Regarding the conventional manufacturing method of ゜5-dialkyl-4-hydroxybenzyl)benzene, for example, Japanese Patent Publication No. 46-4i55
The following method is described in Publication No. 6. That is, 2
, 6-dialkylphenol with formaldehyde or its polymer, a secondary amine, and a carboxylic acid to produce an ester of 6,5-dialkyl-4-hydroxybenzyl alcohol ('), and then the benzyl ester is reacted with sulfuric acid and a 1.3. in the presence of an active solvent.
5-) 1,5.5- by reacting with alkylbenzene
) Realkyl-2,4,6-)lis(3,5-dialkyl-4-hydroxybenzyl)benzenes are known in the art. Furthermore, in the publication, the procedures for isolating and purifying the benzyl ester are omitted, and 1,5.5
- ) realkyl-2,4,6-tris(5,5-dialkyl-4-hydroxybenzyl)benzene in the presence of the entire reaction mixture containing the benzyl ester, which is an intermediate in the production of benzyl ester. .5-) React with listylbenzene to form 1,3.5-) Limete Ru2
．． 4.6-) A simple process for producing lis(5,5-dialkyl-4-hydroxybenzyl)benzene is described.

However, in this method, if the reaction mixture containing the benzyl ester is used as it is as a raw material for the second stage reaction, the acid catalyst is used in a large amount, for example, 10 times the mole of the alkylbenzene. The disadvantage is that it is necessary. As a way to educate yourself on this, in the publication, page 3, right column, lines 12 to 16 and Example 1, dilute the reaction mixture containing the benzyl ester with an inert organic solvent that is immiscible with water, such as methylene chloride, This diluted mixture was then extracted with water, the organic phase of the mixture was dried with a desiccant such as magnesium sulfate, and this was then used as a raw material for the second stage reaction. In some cases, it is stated that the amount of acid catalyst (sulfuric acid) used can be reduced without substantially changing the yield of the desired product. but,
This method requires complicated processing operations and cannot be said to be a practical method when considering industrialization.

[Purpose of the invention]

The present inventors recognized that the prior art related to the production of i,5-trialkyl-2,4,6-tris(5,5-dialkyl-4-hydroxybenzyl)benzene is in the above situation, and We investigated a method for producing the desired product in high yield using an hourly method with a small number of steps.

[Structure of the invention]

As a result, they discovered that the objective could be achieved by using the following method, and completed the present invention.

That is, according to the present invention, a mixture of 2,6-dialkylphenol, formaldehyde (or a polymer thereof), a secondary amine, and a carboxylic acid is reacted while removing water generated from the reaction system while heating. A reaction mixture containing 1-acyloxymethyl-5,5-dialkyl-4-hydroxybenzene was obtained, and the resulting reaction mixture was then reacted with 1,5,5-trialkylbenzene in the presence of an acid catalyst to obtain 1,5-dialkylbenzene. A method for producing .5-)9alkyl-2,4,6-)lis(5,5-dialkyl-4-hydroxybenzyl)benzene is provided.

[Structure of the first stage reaction] In the first stage reaction carried out in the method of the present invention, 2,6-dialkylphenol, formaldehyde (or a polymer thereof), a secondary amine, and a carboxylic acid are used. The mixture was reacted with heating while removing water from the reaction system to form 1-acyloxymethyl-3,5-dialkyl-
A reaction mixture containing 4-hydroxybenzene is obtained.

The 2,6-dialkylphenol used in the present invention is
It is a compound having lower alkyl having about 1 to 5 carbon atoms, specifically 2,6-dimethylphenol, 2,
6-diethylphenol, 2,6-propylphenol, 2,6-di-8ec-butylphenol, 2,6-tart-butylphenol, 2,6-dipentylphenol, 2-methyl-6-tert-butylphenol, etc. For example, 2,6-sheet tert
-Butylphenol is preferred The formaldehyde used in the present invention is generally used in the form of an aqueous solution or a polymer such as paraformaldehyde.

The secondary amine used in the present invention is a dialkylamine having an alkyl group having about 1 to 8 carbon atoms, and specifically includes dimethylamine, diethylamine, methylethylamine, diisopropylamine, dibutylamine, and probylpentylamine. , diethylamine, dioctylamine and the like, among which diethylamine is preferably used.

The carboxylic acid used in the present invention is an aliphatic monocarboxylic acid having about 1 to 12 carbon atoms, and specifically, formic acid,
Examples include acetic acid, propionic acid, butyric acid, pentane acid, dodecanoic acid, etc. Among these, acetic acid is preferred from the viewpoint of economy and ease of carrying out the first stage reaction of the method of the present invention with high efficiency.

The proportions of each of the above-mentioned components to be added in the '1st stage reaction of the present invention can be varied, but usually, the ratio of each component to 1 mole of 2,6-dialkylphenol is
Formaldehyde or its polymer is 1 to 6 mole parts in terms of formaldehyde, and secondary amine is 0.1 to 0.2 parts.
molar parts, and carboxylic acid is 4 to 8 molar parts. If necessary, each of these components may be added in an appropriate amount to satisfy the above range as the reaction progresses, instead of adding the entire amount at once at the start of the reaction.

The temperature of the first stage reaction is usually preferably 80 to 110°C, and the reaction time is usually 6 to 10 hours.

The first stage reaction of the present invention is carried out while removing water from the reaction system. In this case, water can be removed by, for example, incorporating a distillation column into the reactor to remove water by distillation. can be exemplified. The reaction is usually carried out under atmospheric pressure, but if necessary, the pressure can be appropriately reduced to facilitate distillation of water. In the present invention, when a carboxylic acid that is easily miscible with water, such as acetic acid, is used, an amount of carboxylic acid corresponding to the amount of carboxylic acid that is released accompanied by water is added to the charged amount of carboxylic acid. [Effects of the invention due to the configuration of the first stage reaction] One of the features of the present invention is that in the first stage reaction, the reaction is carried out while removing water from the reaction system. By adopting this method, the yield of 1-acyloxymethyl-6,5-dialkyl-4-hydroxybenzene can be increased from about 70% compared to the conventional method. Approximately 80%
and can be improved.

[Structure of the second stage reaction] The second stage reaction carried out in the method of the present invention is performed using the 1-acyloxymethyl-
It consists of reacting a reaction mixture containing 5,5-dialkyl-4-hydroxybenzene with 1.5.5-) realkylbenzene in the presence of an acid catalyst, thereby producing the desired product 1.5.5-) Real Kill-2,4,6-
) Lis(3,5-dialkyl-4-hydroxybenzyl)benzene is obtained.

Examples of acid catalysts used in the present invention include mineral acids such as sulfuric acid and phosphoric acid, organic sulfonic acids such as methanesulfonic acid and para-toluenesulfonic acid, Lewis acids such as aluminum chloride, molybdenum vinegar, and tungstic acid. However, among these, it is preferable to use sulfuric acid◇ The 1,5,5-) real grass rubenzene used in the present invention is a benzene having an alkyl group having about 1 to 5 carbon atoms, and specifically, 1,5- ,5-) Limethylhenzene, 1,5.5-triethylbenzene, 1,5゜5-)
Examples include lyisoprobylbenzene, 1,6-nomethyl-5-ethylbenzene, and 1,5-dimethyl-5-tert-butylbenzene, among which it is preferable to use 1,6°5-trimethylbenzene.

The second stage reaction in the present invention can be carried out using only the reaction mixture obtained in the first stage reaction, an acid catalyst and 1,6°5-trialkylbenzene,
Usually, an inert organic solvent is further added to carry out the reaction.

Examples of the inert organic solvent include pentane, cyclohexane,
Examples include paraffin hydrocarbons such as decane, ethers such as methyl ethyl ether and methyl isopyl ether, and halogenated hydrocarbons such as chloroform, methyl chloride, methyl chloride, methyl bromide, and ethylene dichloride. The use of hydrocarbons is preferred, of which methyl chloride is most preferred.

In the second stage reaction of the present invention, the charging ratio of each component is as follows: 1 mole of 1-acyloxymethyl-5,5-E/'alkyl-4-hydroxybenzene in the first stage reaction mixture. Normally, the range is as follows.

1.5.5-) Realgylbenzene: about 0.25 to about 0.62 mole parts Acid catalyst: about 0.1 to about 3 moles Inert organic solvent: 0 to about 40 moles Second stage in the present invention The temperature of the reaction is about θ to about 100°C, preferably about 5 to about 50°C. The reaction time varies depending on the reaction temperature, amount of catalyst, etc., but is usually about 5 to about 10 hours.

[Separation of target product]

After the completion of the second stage reaction in the present invention, 1. +, 5-) Real kill-2,4゜6-
Tris<5.5-dialkyl-4-hydroxybenzyl)benzene is separated by a method such as crystallization. In particular, in the present invention, after the second stage reaction is completed, for example, when an inert organic solvent with a low boiling point such as a halogenated hydrocarbon is used, only the inert organic solvent is distilled off, and the remaining carbon atoms are mainly removed. This is preferred because crystals of the target product with excellent purity and color can be obtained directly from acid.

〔Effect of the invention〕

In the method of the present invention, the first step is performed while removing water from the reaction system.
By performing the second stage reaction using the reaction mixture obtained by performing the first stage reaction, 1,5.5-)
When the method for producing realkyl-2,4,6-)lis(5゜5-dialkyl-4-hydroxybenzyl)benzene is adopted, the yield of the target product is higher than that of conventional methods, and Since the amount of acid catalyst used is reduced and the production process is simplified, the desired product can be produced economically and at low cost. Also, regarding the effect of carrying out the first stage reaction of the present invention while removing water, Furthermore, when this method is adopted, the reaction mixture in the first stage is not subjected to water extraction treatment to remove water-soluble impurities as in the conventional method (Japanese Patent Publication No. 46-41556). The inventors have discovered that the reaction in the first step can be carried out in high yield, and have thereby completed the simple production process of the present invention.

[Embodiments of the invention]

Hereinafter, the content of the present invention will be explained in more detail with reference to Examples.

Example 1 A 2°6
-sheet tθrt-butylphenol 20.6 g, diethylamine 0.87 g, paraformaldehyde (
Add 6.52 g (purity 95%) and 30 mn of acetic acid one after another, stir at room temperature, and add 10 m+ of acetic acid for addition to the dropping funnel (A).
j? prepared. The flask was immersed in an oil bath and heated to 100°C to react for 8 hours, during which time nitrogen was introduced little by little from the nitrogen inlet (B) and a mixture of water and acetic acid was distilled out at a rate of 1 m4 per hour. While extracting from (0), acetic acid was added from (5) at a rate of 1 ml per hour. Analysis of the reaction mixture by high performance liquid chromatography revealed that the yield of the ester, 2,6-tert-but-4-acetoxymethylphenol, was 86.5%.

The above reaction mixture was cooled to 15°C while adding 50m# of methylene chloride, 2.75 g of 1,3.5-)limethylbenzene was added, and 4 g of concentrated sulfuric acid was added while stirring.
(1,5,5-)limethylbenzene (1.7 times the mole amount) was added dropwise over 50 minutes. Then at 15℃ for 2 hours, 4
After stirring at 0°C for 5 hours, the reaction solution was analyzed by gas chromatography, and it was found that: -Hydroxybenzyl)benzene production amount is 16.
0 g (yield based on 1,5,5-tributylbenzene: 90.4%).

When methylene chloride is distilled out while maintaining the reaction mixture at 40°C while introducing nitrogen, 1,5,5-)lime, 2,4,6-)lis(5,5-di-tert-p,1,000) is obtained.
Crystallization of 1/-4-hydroxybenzyl)benzene began. After cooling to 10°C to complete crystallization and washing the collected crystals with a small amount of acetic acid, a white and highly pure 1.3.5
-) Lime 1,000 Rus 2.4.6-1 Lis (3,5-Gt
ert-butylene-4-hydroxybenzyl]penzene 1
3.9 g was obtained.

Example 2 In Example 1, 78% paraformaldehyde 7.6.
The same procedure was carried out except that 9 g was used. 2゜6-
Yield of tert-butyl-4-acetoxymethylphenol c'i 82.2%, 1,5.5-) Lime 1,000 roux 2.4. 6-) Formation of lith(3,5-tert-butylene-4-hydroxybenzyl)benzene iHa15
．． 8g (1.

3.5-) The yield of remethylbenzene-based fishing is 89.0%.
), the crystallization yield was 15.6 g.

Example 5 The steps up to the ester synthesis step were carried out in the same manner as in Example 1, and the subsequent reaction was carried out using p-)luenesulfo: 44 g (L) instead of sulfuric acid.
! 1.5-) 0.9 times mole relative to remethylbenzene)
It was carried out in exactly the same manner except that . As a result of analysis of the reaction mixture, 1,5.5-) IJ Methyl Ru 2.4.6-
) Lis(5,5-di-tert-butylene-4-hydroxybenzyl)benzene was produced in an amount of 15.8 g (1,
5,5') Yield based on remethylbenzene is 89.0%
) Comparative Example In Example 1, the first stage was carried out without removing water to synthesize 2,6-tert-butyl-4-acetoxymethylphenol. In addition, Example 1 except that 4.25 g of 78% rose formaldehyde was used at this time.
It was carried out in the same way. 2,6-tert-butyl-4
As a result of analysis of the reaction mixture during the -acetoxymethane compound/-ruylation, the yield of the compound was 69%. To this, add 50ml of methylene chloride (1.1,3.5-)limethylbenzene 2.10g and concentrated W&acid 8g (1+5
+5-trimethylbenzene (6.5 times mole) was added according to Example 1, and the mixture was stirred at 15°C for 5 hours and at 40°C for 5 hours. As a result of analyzing the reaction mixture, i, 5.
5-) dimethyl-2,4,6-tris(6,5-di-t)
The amount of produced art-butylene (4-hydroxybenzyl)benzene was 2.6 g, and the crystallization yield after distilling off methylene chloride was 10.15.

[Brief explanation of the drawing]

1, S, 5-)' according to the method of the present invention! J alkyl-2,4.6-)lis(5,5-dialkyl-4
An example of an apparatus for producing (hydroxybenzyl)benzene is shown below. A: Dripping device for adding solvent B; Nitrogen inlet 0: Water outlet D: Stirrer Applicant Mitsui Petrochemical Industries Co., Ltd. Agent Kazuhiro Yamaguchi Figure 1

Claims (1)

[Claims] (1) A mixture of 2,6-dialkylphenol, formaldehyde (or its polymer), secondary amine, and carboxylic acid is reacted with 1-acyloxymethyl- obtaining a reaction mixture containing 3,5-dialkyl-4-hydroxybenzene;
The resulting reaction mixture was then reacted with 1,3,
1,3,5-trialkyl-2,4,6-tris(3
, 5-dialkyl-4-hydroxybenzyl)benzene.