JPH02229125A - Production of 2,6-di-tert-butyl-4-methylphenol - Google Patents

Abstract

PURPOSE:To obtain the subject compound from 2,6-di-tert-butylphenol containing a specific impurity via a 4-methoxymethyl compound by carrying out the evaporation treatment after methoxymethylation, the evaporation and distillation treatment after catalytic decomposition and the crystallization treatment. CONSTITUTION:2,6-Di-tert-butylphenol containing 2,4-di-tert-butylphenol is made to react 1 with methanol and formaldehyde in the presence of a catalyst to form 2,6-di-tert-butyl-4-methoxymethylphenol. The product is subjected to catalytic decomposition 5 in the presence of hydrogen gas and a catalyst to obtain the subject compound useful as a raw material for antioxidant, etc. In the above process, the reaction product of the 1st reaction step 1 is evaporated 2 and the column bottom is subjected to catalytic decomposition 5 and, at the same time, the column bottom produced by the evaporation 7 of the decomposition product is further distilled 1 and the column top distillate is crystallized 11. The objective compound can be produced from the above raw material in high efficiency on an industrial scale at a low cost without using precision fractionation step.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for producing 2,6-di-tert-butyl-4-methylphenol.
The present invention relates to a method for industrially and efficiently producing r t-butyl-4-methylphenol.

(Problems to be solved by conventional techniques and inventions) 2
6-di-tert-butyl-4-methylphenol is
It is a compound useful as an antioxidant and other raw materials.

This 2,6-di-tert-butyl 4-methylphenol can be prepared, for example, in the presence of a tertiary amine as a catalyst.
2,6-di-tert-butylphenol is reacted with methanol and formaldehyde to produce 2,6-di-tert-butylphenol.
To produce butyl-4-methoxymethylphenol (see JP-A-63112529), the 2,6-di-tert-butyl-4-methoxymethylphenol is then catalytically cracked in the presence of hydrogen gas and a copper-chromium catalyst. (See US Pat. No. 3,006,969).

However, the above method is complicated to operate, and the raw material 26-di-tert-butylphenol contains 2,4-di-tert-butylphenol as an impurity derived from its production. It was customary to perform rectification to remove such impurities before using it as a raw material. Furthermore, up to now, there has been no industrial method for producing 26-di-tert-butyl-4-methylphenol from 26-di-tert-butylphenol via 2,6-di-tert-butyl-4-methoxymethylphenol. At present, no practical and efficient manufacturing method has been developed.

[Means for Solving the Problems] Therefore, the present inventor has solved the problem by using 2,4-terres as an impurity.
26-di-te still containing t-butylphenol
We have conducted extensive research to develop an industrially efficient method for producing 26j tert-butyl-4-methylphenol that can use r t-butylphenol as a raw material. As a result, it has been found that the above object can be achieved by performing each step of producing 2,6-di-tert-butyl-4-methylphenol in a specific order.

The present invention was completed based on this knowledge.

That is, according to the present invention, 2,6-di-tert-butylphenol containing 2,4-di-tert-butylphenol is reacted with methanol and formaldehyde in the presence of a catalyst to produce 2,6-di-tert-butylphenol. -4
-methoxymethylphenol, and then the 2,6-di-tert-butyl-4-methoxymethylphenol was catalytically cracked in the presence of hydrogen gas and a catalyst to produce 2,6-di-methoxymethylphenol.
In producing tert-butyl-4 methylphenol, a reaction obtained by reacting 26-di-tert-butylphenol containing the 24-di-tert-butylphenol with methanol and formaldehyde in the presence of a catalyst. The product is evaporated in an evaporation tower, the resulting bottom product is catalytically cracked in the presence of hydrogen gas and a catalyst, and the resulting decomposition reaction product is evaporated in an evaporation tower to obtain further The bottom product is distilled in a distillation column,
The present invention provides a method for producing 26-tert-butyl-4-methylphenol, which is characterized in that the top product obtained after that is subjected to crystallization treatment in a crystallization tower.

Hereinafter, the manufacturing method of the present invention will be explained with reference to the process diagram shown in FIG.

First, the raw materials 2,6-di-tert-butylphenol, methanol, formaldehyde, and a catalyst are introduced into the first reaction tower 1, and reacted according to the following reaction formula (1) to produce 2,6-di-tert- Butyl-4methoxymethylphenol is produced.

CH, OCH.

At this time, the raw material 2,6-di-tert-butylphenol usually contains 2,4-di-tert-butylphenol, but the raw material used in the present invention does not contain 2,4-di-tert-butylphenol as an impurity. 24-tert
-Butylphenol is preferably 10% by weight or less. If this impurity is contained in too large a quantity, there is a risk that production efficiency will decrease. Therefore, 2.4
- If a large amount of di-tert-butylphenol is contained, a simple rectification operation can be performed to reduce the content to 10%.
It is desirable that the content be less than % by weight. Note that this 2.4-di-tert-butylphenol is also the same as the above-mentioned 2,6-di-tert-butylphenol.
Reacts in the same manner as t-butylphenol to form 2,40-di-
tert-butyl-6-methoxymethylphenol is produced. Furthermore, 4,4'methylenebis(2,6-di-tert-butylphenol) and the like are similarly produced as by-products. At the same time, the 24-di-tert-butyl-6-methoxymethylphenol was also catalytically cracked,
A by-product, 2,4-di-tert-butyl-6-methylphenol, is produced.

On the other hand, as the catalyst, various catalysts commonly used in this type of reaction can be used, but it is particularly preferable to use tertiary amines. This tertiary amine is
For example, 1-trimethylamine triethylamine; tripropylamine, tributylamine; triamylamine;
Trihensylamine; triphenylamine; N N-dimethylethylamine; N N-dimethyl-n-propylamine, N N-diethylmethylamine, N N diconithyl-n-propylamine propylethylamine, and the like.

In the method of the present invention, the blending ratios of various raw materials and catalysts are appropriately determined depending on their types and reaction conditions.
For 1 mole of formaldehyde (referred to as DTBP), use 0.5 parapolmaldehyde or formalin.
-10 mol, preferably 1-5 mol, and methanol is 50-20 mol per 1 mol of DTBP.
00 InR, preferably in the range of 100 to 1000 InR. Further, the amount of the catalyst is 1 to 200 g, preferably 10 to 200 g, for example, triethylamine, per 1 mole of DTBP. A range of O O g is suitable.

The reaction conditions in the first reaction tower 1 vary depending on the types and amounts of raw materials and catalysts, but usually the reaction temperature is set at 50°C.
It can be carried out at a temperature of ~200°C, preferably 70-140'C, under natural pressure (self-pressure).

The reaction time is 0.5 to 20 hours, preferably 1 to 10 hours, and the reaction format may be batch, semi-batch, or continuous.

The reaction product produced in the first reaction tower 1 is introduced into the first reaction tower 2, where it is subjected to evaporation treatment. The treatment conditions in the first evaporation column 2 are such that the reaction products and unreacted raw materials are treated in the first evaporation column 2. Although it is determined by the type of catalyst or their ratio, the temperature is usually 50 to 250°C, preferably 10 to 17°C.

°C, and the pressure is 1 to 76 oIllfflIg, preferably L< is l.

~200 mm tl g, it can be carried out for 1 to 10 hours, preferably 2 to 7 hours.

The top product obtained by the evaporation treatment in the first evaporation column 2 is mainly a mixture of the catalyst, methanol added in excess, formaldehyde, water produced by the reaction, and the like. This column overhead product is introduced into the first distillation column 3 and subjected to distillation treatment. This column overhead material is subjected to distillation treatment in the first distillation column 3.
Low-boiling components such as a catalyst such as tertiary amine and methanol are separated at the top of the first distillation column 3, and high-boiling components such as formaldehyde and water are separated at the bottom of the column. This makes it possible to recover the catalyst and methanol at the top of the tower.
If these are collected in the hold tram 4 and introduced into the first reaction tower 1 for reuse, the consumption of raw materials and catalysts can be reduced. The recovery of the catalyst and methanol in the first distillation column 3 can be carried out as appropriate depending on the component state of the catalyst and the top product of the first evaporation column 2.

On the other hand, the bottom of the first evaporation column 2 is mainly 2,6-di-tert-butyl-4-methoxymethylphenol, as described above, and 2,4-di-tert-butyl-4-methoxymethylphenol as a by-product.
tert-butyl-6-medoxymethylphenol and 4
．． Contains 4'-methylenebis (26=di-tert-butylphenol). The bottom product of the first evaporation tower 2 is directly introduced into the second reaction tower 5 without removing heavy components, and in the presence of hydrogen gas and a catalyst, the following reaction formula (
Catalytic cracking according to n) to obtain the desired 2,6-di-te
A decomposition reaction product containing r t-butyl-4-methylphenol is obtained.

C H2O C H3 The catalyst used here can be any of a variety of catalysts that can be used in general hydrogenolysis. Particularly preferred catalysts include copper-chromium-barium catalysts and copper-chromium-barium-manganese catalysts.

When these ternary or quaternary metal catalysts are used, it is preferable that each metal is an oxide. There are no particular restrictions on the proportions of metals in these ternary or quaternary metal catalysts, but in copper-chromium-barium catalysts, copper is usually 20-42% by weight, chromium 17-33% by weight, and barium 2-20% by weight. In copper-chromium-barium manganese catalysts, copper is usually 15 to 45% by weight, chromium is 12 to 40% by weight, and barium is 0.5 to 15% by weight.
The amount of this catalyst used is not particularly limited, but usually,
The amount is in the range of 0.1 to 100 g, preferably 1 to 50 g per 1 kg of the column bottom material. If the amount of catalyst used is small,
2,6-di-t, which is the target product, does not exhibit sufficient catalytic action.
The yield of er t-butyl-4-methylphenol may decrease. On the other hand, even if it is used in excess, it cannot be expected to improve the yield commensurate with the amount used.

Further, a carrier is not particularly required, but if desired, silica,
Alumina, magnesium, zirconia niobium oxide, thoria, boria, silica-alumina.

Silica-magnesia, chromia-alumina, alumina
Boria, molybdenor alumina, tungsten oxide-alumina 1 silica-titania zeolite, high silica zeolite, mordenite, gallosilicate, iron silicate, silicalite hojazite, crystalline aluminum phosphate, perovskite, clay, activated carbon, carbonized fiber 5 diatomaceous earth, etc. It is also possible to use one supported on a carrier.

Additionally, this reaction can be performed using methanol and ethanol.

Alcohols such as isopropanol and pentane.

The process can be carried out using aliphatic hydrocarbons such as hexane, heptane, octane, nonane, decane, etc. as a solvent. The amount of these solvents is 200 ~
5000 ml, preferably in the range of 500-3000 mfl.

The decomposition reaction in the second reaction tower 5 can be carried out under general conditions. That is, the reaction temperature is 80-2
50°C, preferably 100 to 200°C. If the reaction temperature is too low, the reaction will not proceed sufficiently, and
If it is too high, side reactions may occur and the yield of the target product may not be sufficiently increased.

In addition, the pressure of hydrogen gas is 0 to 100 kg/cnlG,
Preferably, it is selected within the range of 10 to 50 kg/+JG.

If the pressure of hydrogen gas is too low, the reaction may not proceed sufficiently, and if it is too high, the result may not be reflected in the improvement in yield. It is preferable that the hydrogen used here be sufficiently purified, for example, water electrolysis, water gas denaturation, etc.
Those obtained by various methods such as gasification of petroleum and modification of natural gas can be used. In some cases, a mixed gas of hydrogen gas and an inert gas, such as nitrogen, helium, or argon, may be used. When using a mixed gas, it is preferable to adjust the hydrogen partial pressure to the above hydrogen gas pressure.

The reaction time in the second reaction tower 5 is usually 0.5 to 10 hours, preferably 1 to 8 hours. This reaction time is 0,
If it is shorter than 5 hours, 2,6-tert-butyl-4-methylphenol will not be sufficiently produced, and 1
Even if it is longer than 0 hours, 2゜6-di-tert-butyl-
This tends not to contribute much to improving the yield of 4-methylphenol.

The reaction format of this second reaction column 5 can be any of a batch type, semi-batch type, and continuous type. In addition, before introducing into the second reaction tower 5, evaporation treatment is performed in advance according to a conventional method to remove heavy components and the like, and the target 26-di-
It is also possible to perform hydrogenolysis after obtaining only 2,6-di-tert-butyl-4-methoxymethylphenol, which is the raw material for producing tert-butyl-4-methylphenol. (decomposition reaction product) is introduced into a filter 6 to separate the catalyst, if necessary, and is further introduced into a second evaporation column 7δ for evaporation treatment. In the evaporation treatment carried out in the second evaporation column 7, the temperature is usually 50 to 250°C, preferably 70 to 150°C.
and the pressure is 1 to 760 mmHg, preferably 10 to 760 mmHg.
This can be carried out under conditions of 500 mmHg. Through this evaporation treatment, 2,6-di-tert-butyl-4-methylphenol and the like produced by the hydrogenolysis reaction can be taken out as a bottom product, and the alcohol added as a solvent in the second reaction tower 5 can be removed. Solvents such as can be separated as overhead. The top of the second evaporation tower 7 is then introduced into the third evaporation tower 8, where it is evaporated with acid added thereto. The evaporation process in the third evaporation tower 8 involves recovering the solvent added to the second reaction tower 5, and adding it to the first reaction tower 1 as a catalyst, which accompanies the products of each stage. This is carried out for the purpose of removing nitrogen compounds (tertiary amines or reactants derived therefrom). As the acid, mineral acids such as sulfuric acid, hydrochloric acid, nitric acid, and phosphoric acid, and organic acids such as formic acid and acetic acid can be used, and the amount added depends on the amount and properties of nitrogen compounds contained in the tower top. Although different, it is desirable to add a sufficient amount to remove the nitrogen compound as a salt through a neutralization reaction.

Further, the conditions for the evaporation treatment are set within a range that allows the solvent to be evaporated and recovered. For example, change the temperature to 40-250°C1
Preferably the temperature is 60-150°C and the pressure is 1 mmHg.
~5 kg/clfl, preferably 10-760mm
As for Hg, the treatment can be carried out for 0.5 to 10 hours, preferably 1 to 5 hours.

The solvent recovered by the second evaporation tower 8 can be introduced into the second reaction tower 5 again via the hold tram 9, and a portion can be introduced into the first reaction tower 1 as a solvent. This results in
It is possible to reduce the amount of solvent used. Further, by adding acid in the third evaporation column 8 and performing evaporation treatment, nitrogen compounds can be removed and accumulation of nitrogen compounds in the hydrogenolysis system can be prevented.

On the other hand, the bottom product of the second evaporation column 7 is mainly 2,6-di-tert-butyl-4 methylphenol which is the target product, but 24-di-tert-butyl-4 methylphenol is the by-product.
t-butyl-6-methylphenol; 24-di-ter
t-phthyl-6-meth4-dimethylphenol and 4
4゛methylenebis(2,6-di-tert(2,6-di-
tert-butylphenol). Therefore, by introducing this column bottom product into the first distillation column 10 and subjecting it to distillation treatment, these by-products mainly consisting of heavy components can be separated at the column bottom.

Further, the top product of the second distillation column 10 is purified in the same manner as in the conventional purification process to obtain the target 2,6-di-tert-butyl-4
-Methylphenol can be obtained. In this purification process, water, alcohol, etc. are added to the top product of the second distillation column 10, and the crystallization process is performed in the crystallization column 11, followed by filtering with the filter 12 to obtain 2.6-di-tert- Butyl-
This can be carried out by a method such as separating 4-methylphenol and then drying it in a dryer 13. In addition, the filtrate from the filter 12 is distilled in the third distillation column 14 to remove unreacted 2,4-di-2,4-di-di-2, and other heavy components such as alcohol.
tert-butylphenol and by-product 24-di-
Tert-butyl-6-medoxymethylphenol can be separated, alcohol etc. can be separated using Bold Drum J.
5 can be reused.

Note that it is not necessary to recover the catalyst and solvent that have passed into the first distillation column 3 and the third evaporation column 8, and it is not necessary to perform evaporation treatment between the first evaporation column 2 and the second reaction column 5. Although 2,6-ditar t-butyl-4-methylphenol can be produced in the same way by performing these steps, by performing at least one of these steps, it is possible to reduce production costs and improve production efficiency. be able to.

[Example] Next, the present invention will be explained in more detail with reference to Examples. Note that the apparatus shown in FIG. 1 is used as the apparatus, and the explanation of this embodiment will be made for each apparatus.

a) In a first reaction column with a first reaction column capacity of 300 mR, 2,4-di-tert
-2,6-di-t containing 3% by weight of butylphenol
80 g (0.39 mol) of ert-butylphenol, 13.9 g of formaldehyde, 200 g of methanol, and 32 g of triethylamine as a catalyst were charged.
The reaction was carried out at °C for 7 hours.

After the reaction was completed, gas chromatography analysis of the product revealed that 2,6-di-tert-butyl-4-methoxymethylphenol was 89% by weight and 4.4''-methylenebis(26tert-butylphenol) was 3.5% by weight. 4
The yield was % by weight.

b) First evaporation tower The reaction product of the first reaction tower is heated to 110″C in the first evaporation tower.
, 760 ng of coconut for 1 hour, and further at 160°C.

Evaporation treatment was performed at 20 mmHg for 20 minutes. The bottom product after the treatment contained 89% by weight of 2,6-di-tert-butyl-4-methoxymethylphenol, and contained 1100 ppm by weight of nitrogen based on total nitrogen analysis.

C) First Distillation Column The top of the first evaporation column was distilled using a concentric precision fractionator (HC-5500F, manufactured by Shibata Kagaku Kikai Kogyo ■) at a top temperature of 65° C. and a pressure cuff of 60 mm and 11 g.

The top product was a mixture of methanol and triethylamine, and the water content was less than 500 ppm by weight.

Furthermore, as a result of gas chromatography analysis of the column overhead material, the amount of triethylamine in the column overhead material was 31 g.

As a result, most of the triethylamine added as a catalyst to the first reaction tower could be recovered.

d) 94g of the bottom of the second reaction column and the first evaporation column and 0.47g of the copper-chromium catalyst
g and 190 ml of methanol were charged into the second reaction tower, and the hydrogen gas was kept at a constant pressure of 30 kg/c+flG.
The reaction was carried out at 140°C for 4.5 hours.

After the reaction was completed, gas chromatography analysis of the product revealed that 2,6-di-tert-butyl-4-methylphenol was 89.7% by weight and 4,4'methylenebis(
26-di-tert-butylphenol) is 3.3% by weight, and 2,4-di-tert-butylphenol is 0.5% by weight.
The yield of 2,4-di-tert-butyl-6-medoxymethylphenol was 1.5% by weight.

e) Second evaporation tower The mother liquor from which the catalyst in the reaction solution in the second reaction tower was removed using a filter was heated in the second evaporation tower at 80°C and 760mmHg for 1 hour, and then at 80°C and 20mm 11g for 20 minutes. Evaporation treatment was performed.

A total nitrogen analysis of the methanol recovered at the top of the column revealed that it contained 400 ppm by weight of nitrogen.

f) Add 1 g of sulfuric acid to the top of the second evaporation tower, and heat to 65'C, 7
Evaporation treatment was performed at 60+n+nHg. A total nitrogen analysis of the top product (recovered methanol) of the third evaporation column revealed that the nitrogen content had decreased to 1 ppm by weight or less. As a result, most of the nitrogen compounds in the recovered methanol could be removed.

g) Second distillation column The bottom product of the second evaporation column is heated to 127°C 10m in the second distillation column.
Distillation was carried out at mHg.

69.4 g of 2.6-di-tert-butyl-4-methylphenol (total yield: 81.2 mol%) was obtained from the top of the column. This 2,6-di-tert-butyl-4-methylphenol contained 0.47% by weight of 2,4-di-tert-butylphenol and 0.86% by weight of 2,6-di-tert-butylphenol as impurities.
, 4-di-tert-butyl-6methoxymethylphenol.

Thereafter, crystallization treatment was performed in the same manner as in the conventional method, and 2゜6-di-
tert-butyl-4-methylphenol was purified.

[Effects of the Invention] As explained above, according to the present invention, since 2,6-di-tert-butyl-4-methylphenol is produced through a specific process, impurities are easily and reliably removed from the subsequent stage. Can be separated during the process. Therefore, as an impurity, 2
, 2 containing 4-di-tert-butylphenol,
It has become possible to use 6-di-tert-butylphenol as a raw material, and it has become possible to use 2,6-di-tert-butylphenol, which was previously required.
The advanced rectification step of tert-butylphenol can be omitted.

Therefore, according to the method of the present invention, it is possible to provide 26-di-tert-butyl-4-methylphenol, which is a raw material for various chemical products, at a low cost.

[Brief explanation of the drawing]

FIG. 1 is a process diagram showing an example of the manufacturing process for carrying out the method of the present invention. 1... First reaction column, 2... First evaporation column 3...
・First distillation column, 4... Bold drum 5...
Second reaction column, 6... Filter 7... Second evaporation column, 8... Third evaporation column 9... Hold drum,
10...Second distillation column 11...Crystallization tower, 12...Filter 13...Dryer, 14...Third distillation column 15...Hold drum

Claims (1)

[Claims] (1) 2,6-di-tert-butylphenol containing 2,4-di-tert-butylphenol is reacted with methanol and formaldehyde in the presence of a catalyst to produce 2,6-di-tert-butyl-4 -methoxymethylphenol and then the 2,6-di-tert-
In producing 2,6-di-tert-butyl-4-methylphenol by catalytic cracking of butyl-4-methoxymethylphenol in the presence of hydrogen gas and a catalyst, the 2,4-di-tert-butylphenol is Contains 2
, 6-di-tert-butylphenol, methanol and formaldehyde are reacted in the presence of a catalyst, the reaction product is evaporated in an evaporation column, and the bottom product obtained is evaporated in the presence of hydrogen gas and a catalyst. The resulting decomposition reaction product is evaporated in an evaporation column, the bottom product is distilled in a distillation column, and then the top product is transferred to a crystallization column. 1. A method for producing 2,6-di-tert-butyl-4-methylphenol, which comprises performing a crystallization treatment in .