JPH0774176B2 - Process for producing 2-t-butyl-6-alkylphenol - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing 2-t-butyl-6-alkylphenol from o-alkylphenol and isobutylene.

[Conventional technology]

2-t-butyl-from o-cresol and isobutylene
As a method for producing 6-methylphenol, a method of using sulfuric acid as a catalyst (US Pat. No. 2,836,627) and a catalyst of T
_{i (OAr) n · (Ar'So} 3) 4-n ( provided that Ar, Ar 'is an aryl radical, n is from 3 to 3.9) How to use (U.S. Pat. No. 3, 26
7,152), a method of using titanium catecholate as a catalyst (US Pat. No. 3,267,155), a method of using an aluminum halide as a catalyst (US Pat. No. 2,923,745), and the like.

[Problems to be Solved by the Invention] However, the above conventional methods have the following problems. First, the method of using sulfuric acid as a catalyst contains a large amount of 4-t-butyl-6-methylphenol as a by-product (25%).
Since it is produced, the yield of the desired product is extremely low at 50%. Further, in the method of using Ti (OAr) _n · (Ar′SO ₃ ) _4-n or titanium catecholate as a catalyst, hydrogen chloride gas is generated when TiCl ₄ is reacted with phenol or catechol to prepare a catalyst. Since it occurs, there is a problem of reactor corrosion, and the yield of the target product is 41%, which is considerably low. Further, the method of using aluminum halide as a catalyst also generates hydrogen halide gas, which causes a problem of reactor corrosion.

The present invention is to solve the above problems, and proposes a method for producing 2-t-butyl-6-alkylphenol, which is free from corrosion, has a high reaction yield, and is easy to remove the catalyst. Has an aim.

[Means for solving problems]

In the present invention, an o-alkylphenol and isobutylene are reacted in the presence of an aluminum o-alkylphenolate catalyst, the reaction mixture is washed with an aqueous acid solution, and the catalyst is hydrolyzed and removed together with washing waste water, and then an alkaline aqueous solution is used. A method for producing 2-t-butyl-6-alkylphenol, which comprises washing.

The 2-t-butyl-6-alkylphenol produced in the present invention is not particularly limited, but the alkyl group bonded to the 6-position includes, for example, a lower alkyl group having 6 or less carbon atoms.

The o-alkylphenol which is a raw material in the present invention is not particularly limited, and is an o-alkylphenol corresponding to the desired 2-t-butyl-6-alkylphenol such as o-cresol and o-ethylphenol, The water content is preferably 1000 ppm or less.

As isobutylene, pure isobutylene or butene gas containing isobutylene can be used.

The catalyst used in these reactions is aluminum o-alkylphenolate, which is obtained by the reaction of metallic aluminum with o-alkylphenols. Although this catalyst may be prepared separately, it may be used as a starting material in the production of 2-t-butyl-6-alkylphenol.
The catalyst can also be prepared by reacting an alkylphenol with aluminum metal.

Hereinafter, a preferable manufacturing method of the present invention will be described based on a systematic diagram of the drawings. The drawing shows a preferred embodiment, 1 is a catalyst preparation tank, 2 is a reactor, 3 is a catalyst removal tank, and 4 is a distillation column. The manufacturing process by this apparatus consists of four steps of catalyst preparation step, reaction step, catalyst removal step and distillation purification step.

The catalyst preparation process is carried out under the nitrogen atmosphere with metallic aluminum and o-
It is a step of reacting with an alkylphenol to prepare an aluminum o-alkylphenolate catalyst. Although metal aluminum and o-alkylphenol are supplied to the catalyst preparation tank 1 to prepare the catalyst, the catalyst preparation tank 1 may be omitted and the catalyst may be prepared in the reactor 2.
In this catalyst preparation step, the amount of aluminum metal / o-alkylphenol is 0.1 to 10% by weight, preferably 0.3 to 5% by weight, the reaction temperature is 130 to 300 ° C, preferably 160 to 220 ° C, and the pressure is 0.1 to 10% at atmospheric pressure or higher. The reaction is carried out for a period of time, preferably 0.1-5 hours, in solution or partially suspended.

The reaction step is a step of producing a 2-t-butyl-6-alkylphenol by reacting an o-alkylphenol with isobutylene in the presence of an aluminum o-alkylphenolate catalyst under a nitrogen, hydrogen or mixed gas atmosphere thereof. is there. After supplying the catalyst and the excess o-alkylphenol from the catalyst preparation tank 1 to the reactor 2, isobutylene is supplied and the reaction of the o-alkylphenol and isobutylene is performed. When the catalyst is prepared in the reactor 2, isobutylene is supplied after the preparation of the catalyst to carry out the reaction.

In this reaction step, isobutylene / o-alkylphenol (molar ratio) is 0.5 to 3, preferably 0.7 to 1.5, and the temperature is 5
0 ~ 180 ℃, preferably 70 ~ 130 ℃, 0.1 ~ above normal pressure
The reaction is carried out in the liquid phase for 20 hours, preferably 0.1 to 10 hours. Isobutylene / o-alkylphenol (molar ratio) 1.1, A
0.015 (molar ratio) of l / o-alkylphenol, reaction temperature
When the reaction time is 4 hours at 100 ° C., the concentration of 2-t-butyl-6-alkylphenol produced is 88% by weight and the yield is about 90 mol%.

Unreacted isobutylene is purged after completion of the reaction or in the next catalyst removal step. The above reaction may be a batch system or a continuous system. An isobutylene recovery device is required to make it continuous, but this device may also be attached to a batch type.

The catalyst removing step is carried out in a catalyst removing tank 3 at a temperature of 50 to 95 ° C., preferably 60 to 90 ° C. with an aqueous acid solution such as an aqueous sulfuric acid solution.
Wash ~ 5 times to hydrolyze catalyst and remove with wash drain. The hydrolyzed aluminum transfers to the aqueous phase and is easily removed without depositing as a solid or gel. The o-alkylphenol remains in the oil phase and is reused as a raw material. After that, add 1 with alkaline solution such as sodium hydroxide solution or sodium carbonate solution.
Wash ~ 5 times. When washing with an alkaline aqueous solution, the oil phase has a pH
Repeat until it is 7 or more. As a result, the free acid remaining in the oil phase is removed, and the product, 2-t-butyl-6-
The decomposition of alkylphenol is prevented. After washing with the alkaline aqueous solution, washing with water may be performed 1 to 5 times. Oily
For the pH measurement method, water having the same volume as that of the oil phase, adjusted to pH 7.0, is put into a separating funnel, shaken for 10 minutes, and allowed to stand for 10 minutes or longer. After oil-water separation, the pH of the water phase is measured.

The concentration of the acid aqueous solution is 1 to 30% by weight, preferably 3 to 15% by weight, and the concentration of the alkaline aqueous solution is 1 to 30% by weight, preferably 3 to 15% by weight. The amount of the acid aqueous solution used for the first washing is such that the amount of acid contained therein is 1/2 to 10 equivalents, preferably 1/2 to 3 equivalents of Al of the catalyst. Is 1/20 to 2 times, preferably 1/10 to 1 times the amount of the first time. The amount of the first alkaline aqueous solution is 0.01 to 5 times, preferably 0.1 to 2 times the equivalent amount of the acid amount contained in the final acidic aqueous solution, preferably 0.1 to 2 times, and the second and subsequent 1/20 times of the first. ~ Double amount,
The amount is preferably 1/10 to 1 time. The stirring time for cleaning
0.01-5 hours, preferably 0.1-2 hours, standing time 0.1
~ 5 hours, preferably 0.1-2 hours.

The distillation purification step is a step of purifying the produced 2-t-butyl-6-alkylphenol by distillation and collecting it as a product. In this step, the reaction liquid from which the catalyst has been removed in the catalyst removal tank 3 is purified by distillation in the distillation column 4. The distillation column 4 comprises a topping column 4a and a tailing column 4b. In the topping column 4a, low boiling fractions such as o-alkylphenol and water are removed, and in the tailing column 4b, 2-t-butyl-6-alkylphenol as a product is removed. Collect and discharge the distillation residue.

2-t-butyl-in the catalyst removal step and the distillation purification step
The 6-alkylphenol did not decompose at all, and the distillation recovery rate was
More than 99%. The 2-t-butyl-6-alkylphenol produced as described above is used as a raw material for resin additives.

〔The invention's effect〕

According to the present invention, an o-alkylphenol and isobutylene are reacted in the presence of an aluminum o-alkylphenolate catalyst, the reaction mixture is washed with an aqueous acid solution, and the catalyst is hydrolyzed to remove it with washing wastewater, followed by alkali removal. Since it was cleaned with an aqueous solution, there is no risk of corrosion if the reactor is made of corrosion resistant steel, which is a general material,
The reaction yield of -butyl-6-alkylphenol is good, and a large amount of impurities that are difficult to separate are not produced during distillation purification. Removal of the catalyst is also easy, aluminum produced by hydrolysis is removed without precipitation as a solid or gel, and o-alkylphenol remains as it is for reuse as a raw material, and residual free acid is removed. , It is possible to prevent the decomposition of the product.
Further, the catalyst can be prepared from aluminum metal and o-alkylphenol, so the catalyst cost is low. Furthermore, since the process is simple, the facility cost is low, existing equipment can be easily converted, and handling is easy.

〔Example〕

Examples of the present invention will be described below. Unless otherwise specified,% in each example is% by weight.

Example 1 A 1-volume corrosion-resistant steel (SUS) autoclave equipped with an isobutylene supply pipe, a thermometer sheath, and a rotary stirring device,
230 g of o-cresol and 0.9 g of metallic aluminum were charged.

On the other hand, the head portion of the isobutylene supply pump connected to the isobutylene supply port of the autoclave is cooled to -10 ° C or lower, and an isobutylene cylinder is connected to the head. Then, the inside of the autoclave was replaced with nitrogen, and heating was started.

When the internal temperature of the autoclave reached 190 ° C., the temperature was maintained and the mixture was stirred for 1 hour and 30 minutes to prepare a catalyst (aluminum o-cresolate). Then, the internal temperature of the autoclave was cooled to 100 ° C. and depressurized, the by-produced hydrogen gas was released to the outside of the system, and the inside of the autoclave was further replaced with nitrogen.

Then, by operating the isobutylene supply pump, 130 g of isobutylene was supplied over 1 hour while maintaining the reaction temperature of 100 ° C, and further post-reaction was carried out at the reaction temperature of 100 ° C for 3 hours to obtain 2-t-butyl- 6-Methylphenol was produced. After completion of the reaction, a part of the reaction mixture was taken out and a small amount of water was added to hydrolyze the catalyst. When this reaction mixture was analyzed using a gas chromatography analyzer, the concentration of 2-t-butyl-6-methylphenol was 88.
% (Yield 90 mol%).

Example 2 320 g of the reaction solution (before hydrolysis) synthesized in Example 1 was charged into a flask equipped with a heat-retaining jacket and equipped with a draining cock equipped with a cooling tube, a thermometer and a rotary stirrer, and warm water was passed through the jacket. The internal temperature was raised to 70 ° C. Inner temperature is 70
When the temperature reaches ℃, 200m of 10% sulfuric acid solution while stirring
l was added and stirred for 1 hour. Then, the mixture was allowed to stand for 1 hour, and the aqueous phase was extracted. 50 ml of 10% sulfuric acid aqueous solution while stirring again
Was added, and the mixture was stirred for 1 hour and allowed to stand for 1 hour, and the aqueous phase was extracted. Then, with stirring, 10% aqueous sodium carbonate solution
After adding 30 ml, the mixture was stirred for 1 hour and allowed to stand for 1 hour, and the aqueous phase was extracted. Furthermore, 30 ml of a 10% sodium carbonate aqueous solution was added with stirring, and the mixture was stirred for 1 hour and allowed to stand for 1 hour, and the aqueous phase was extracted. As a result, the washing oil phase (catalyst removal oil phase) 32
I got 1g. The pH of this wash oil phase was 7.5, and when a part of this wash oil phase was analyzed by a gas chromatography analyzer, the concentration of 2-t-butyl-6-methylphenol was 88%. Comparison of this value with the results of Example 1 shows that no decomposition occurred during catalyst removal (washing).

Next, 303.9 g of this washed oil phase was subjected to distillation purification using a 15-stage Oldershaw distillation apparatus, and as a result, 2-t- with a purity of 99.1% was obtained.
Butyl-6-methylphenol fraction (132-135 ℃ / 22mmH
255.5 g of g) was obtained. Distillation recovery rate at this time is 99.1%
And no decomposition occurred at the time of distillation.

Example 3 Using the catalyst prepared in the same manner as in Example 1, Example 1
The experiment was conducted by changing the reaction temperature of 95 ° C., the amount of isobutylene to 115 g, and the post reaction time to 6 hours. As a result, 2-t-
The yield of butyl-6-methylphenol was 83 mol%.

Example 4 Using the catalyst prepared in the same manner as in Example 1, Example 1
The experiment was conducted by changing the reaction temperature of 110 ° C., the amount of isobutylene to 142 g, and the post-reaction time to 1 hour. As a result, 2-t
The yield of -butyl-6-methylphenol was 82 mol%.

[Brief description of drawings]

 The drawing is a systematic diagram showing an embodiment.

Claims (3)

[Claims] 1. An o-alkylphenol and isobutylene are reacted in the presence of an aluminum o-alkylphenolate catalyst, the reaction mixture is washed with an aqueous acid solution, the catalyst is hydrolyzed and removed together with washing waste water, and then an aqueous alkali solution is used. 2-t-butyl-6-, characterized by being washed with
Method for producing alkylphenol. 2. The production method according to claim 1, wherein the isobutylene is pure isobutylene or isobutylene-containing butene gas. 3. The method according to claim 1 or 2, wherein the aluminum o-alkylphenolate catalyst is obtained by reacting aluminum metal with o-alkylphenol.