JPH0237332B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a catalyst in which a metal oxide is pretreated with a phenol, and a method for activating a phenolate-containing catalyst, which is used in a method for producing alkylphenols by reacting phenols and alcohols. .

Alkylphenols, especially the orthoalkylated 2,6-xylenol, are not only important as raw materials for the production of polyphenylene ether (PPE), a useful plastic, but also as resins, plasticizers, and antioxidants. It is well known that it is used as a raw material for disinfectants, fungicides, agricultural chemicals, etc.

Aluminum oxide, magnesium oxide, manganese oxide,
It is known to use iron oxide, chromium oxide, zeolite, etc., or their mixtures with various components as catalysts. Furthermore, in order to improve the overall performance of these catalysts, the present inventors have proposed a method in which these metal oxides are treated with phenols and then used as catalysts, and a method in which phenolates of these metals are used as catalysts. (Japanese Patent Application Laid-Open No. 58-38225, Japanese Patent Application Laid-open No. 128333-1982)
Publication No.).

However, even in the metal oxide catalyst and the phenolate catalyst, the induction period of the catalyst is long, and it often takes a long time, such as several tens of hours, for the catalyst activity to reach a steady state.

The present inventors have studied various ways to shorten the induction period of such catalysts, and have found that these objectives can be easily achieved by pretreatment with a water vapor-containing gas, and have completed the present invention. .

That is, the present invention provides a method for producing alkylphenols by reacting phenols having at least one hydrogen atom on an aromatic ring with alcohols, which contain at least one of magnesium, manganese, and iron. This is a method for producing alkylphenols, which comprises treating a catalyst obtained by treating an oxide with phenols or a catalyst containing magnesium phenol with a steam-containing gas at a temperature of 300°C or more and 700°C or less.

The phenols used in the method of the present invention are phenolic compounds having one or more hydrogen atoms on the aromatic ring, and have the general formula (In the formula, R ₁ to _{R 5} are hydrogen, a hydrocarbon group, a hydroxyl group, or an unsubstituted or substituted aromatic hydrocarbon group such as phenyl or naphthyl, and at least one of them is a hydrogen atom.) It is expressed as Examples of such compounds include phenols, cresols, xylenols, trimethylphenols, various ethylphenols, n-, iso-, and tert-butylphenols,
Examples include phenylphenols and naphthylphenols. Similarly, phenol compounds in which one or more different functional groups are substituted on the aromatic ring can also be used.

The alcohols used in the method of the present invention are lower alcohols having 1 to 4 carbon atoms, such as methanol, ethanol, n-propanol, iso-
Examples include propanol, n-butanol, iso-butanol, and tert-butanol.

The reaction temperature for producing alkylphenols is
Although the reaction can be carried out at 300 to 600°C, preferably 350 to 540°C, and the reaction pressure is below atmospheric pressure, it is usually carried out under normal pressure or increased pressure. In order to obtain the highest yields of alkylated products, the alcohol should be methylated at least 1 mole, preferably 2 to 4 moles, per hydrogen atom of the phenol to be alkylated to give 2,6-xylenol in high yields. If you want to obtain it, add 4 to 4 methanol per mole of phenol.
It is desirable to use 8 mol. The raw material is preferably supplied to the reaction system at a liquid hourly space velocity of 0.2 to 10 hr ^-1 .
Generally, in a region where the reaction temperature is high, a direction in which the liquid hourly space velocity is large is appropriate, and in a region where the reaction temperature is low, a direction in which the liquid hourly space velocity is small is appropriate. It is also possible to include an inert gas such as nitrogen, or a reducing gas such as hydrogen or carbon monoxide when supplying the raw material. Oxides of alkaline earth metals, earth metals, transition elements, etc. are effective as metal oxides treated with phenols and used as catalysts, but oxides containing at least one of magnesium, manganese and iron are particularly effective. Preferably. In addition, the metal component elements of phenolates used as catalysts include alkali metals, alkaline earth metals, earth metals, transition elements, etc. Among them, magnesium is particularly good when used in the production of alkylphenols. It is recognized that this catalyst exhibits much higher performance than conventional catalysts, such as improved catalytic activity, improved ortho-selectivity, and extended catalyst life due to lower reaction temperatures. The metal oxide treated with phenols is granulated into an optimal shape by a conventional method, either alone or in combination with a binder. Phenolates can be used as they are after being made into an appropriate shape and strength by a conventional granulation method, but they can also be used after being impregnated with a metal oxide carrier, coated, or mixed. As the metal oxide carrier, common catalyst carriers such as alumina, silica, magnesia, titania, and zirconia can be used.

The catalyst obtained in this way can be heated to temperatures above 300°C and 700°C.
Processed through water vapor-containing gas under the following temperature conditions: In this case, if the treatment temperature is as low as 300°C or less, the induction time can be shortened, but the catalyst life tends to be shortened. There are no particular restrictions as long as the temperature is 300℃ or higher, but in industry it is generally 300℃ or higher.
Suitable results can be obtained when carried out at a temperature of about 700°C.

Although there are no particular restrictions on the water vapor concentration of the water vapor-containing gas used in the method of the present invention, in general, when the water vapor concentration is low, it tends to require a long time.

Further, the gas entrained in the water vapor at this time may be an inert gas, and nitrogen, carbon dioxide, etc. are used.

Treatment of the catalyst with a steam-containing gas is accomplished by contacting the catalyst with steam under the temperature conditions described above, but is generally carried out by passing the steam-containing gas through the catalyst bed.

As described above, according to the method of the present invention, the time required to activate the catalyst can be easily shortened by the simple operation of treatment with a water vapor-containing gas, and therefore it is extremely useful industrially.

The present invention will be described in more detail below with reference to Examples, but the present invention is not limited by these Examples.

The catalyst performance in Examples and Comparative Examples is shown by the phenol conversion rate and 2,6-xylenol selectivity, and each is defined by the following formula.

Conversion rate of phenol = (1 - Amount of unreacted phenol (mol) / Amount of phenol supplied) × 100 Selectivity of 2,6-xylenol based on phenol = Amount of 2,6-xylenol produced (mol) / Amount of phenol supplied (mol) - Amount of unreacted phenol (mol) x 100 2,6-xylenol selectivity based on phenol = 2 x Amount of 2,6-xylenol produced (mol) / Amount of methanol supplied (mol) - Amount of unreacted methanol (mol) x 10
0 Furthermore, activation refers to the time after the start of the reaction when the selectivity of 2,6-xylenol (based on phenol) reaches 90%.

Example 1 282 g of phenol was added to 86 g of magnesium methylate synthesized from magnesium metal and methanol, and after heating and dissolving at 70°C, 300 ml of n-heptane was added.
The mixture was refluxed at 98° C. for a day and night, then cooled and heptane, phenol and methanol were removed by evaporation using a rotary evaporator to obtain 170 g of magnesium phenolate. Take 10g of this, mix well with 90g of magnesium oxide powder, press-mold, rectify 10 to 16 meshes, fill a quartz reaction tube with 20ml of the mixture as a catalyst for methylation of phenol, and use nitrogen at 30ml/min and water at 33.0ml/min. hr and catalyst layer temperature 400
The catalyst was treated for 3 hours at .degree.
Then LHSV1.65hr ^-1 , methanol:phenol:
When the reaction was carried out at a temperature of 500° C. with a molar ratio of water of 5:1:1.69, the time required for activation was 30 hours. At a reaction temperature of 490°C, the phenol conversion rate was 94%, the 2,6-xylenol selectivity based on phenol was 91%, and the selectivity based on methanol was 79%.
It was %.

Example 2 Commercially available magnesium oxide powder was calcined at 550° C. for 3 hours, then pressure molded and subsequently sized to obtain a granular catalyst of 10 to 16 meshes. After filling 20ml of this catalyst into a quartz reaction tube, nitrogen 60ml/min, phenol
The treatment was carried out at a catalyst bed temperature of 500° C. for 2 hours at a rate of 0.9 g/hr. Subsequently, the catalyst was treated at a catalyst bed temperature of 500° C. for 5 hours while passing nitrogen at 30 ml/min and water at 16.5 ml/hr. Using this catalyst, LHSV1.65hr ^-1 , methanol:phenol:water in a molar ratio of 5:1:
When the reaction was carried out at a temperature of 500°C with 1.69, it took 24 hours to activate. At a reaction temperature of 480°C, the phenol conversion rate is 100%, the 2,6-xylenol selectivity based on phenol is 97%, and the 2,6-xylenol selectivity based on methanol is 86.
It was %.

Comparative Example 1 The reaction was carried out in the same manner as in Example 2 except that water was not used to treat the catalyst, and the time until activation was 33 hours. At a reaction temperature of 490 DEG C., the phenol conversion rate was 96%, the 2,6-xylenol selectivity based on phenol was 93%, and the 2,6-xylenol selectivity based on methanol was 83%.

Example 3 Commercially available granular manganese dioxide was calcined at 500°C for 5 hours and then pulverized into 10 to 16 meshes. This catalyst 20
ml was charged into a quartz reaction tube, treated with nitrogen at 60 ml/min, phenol at 10 g/hr, and catalyst bed temperature at 450°C for 3 hours, and then nitrogen at 30 ml/min and water at 20 ml/hr at catalyst bed temperature at 430°C. The catalyst was treated.

Next, when the reaction was carried out at a temperature of 430°C with a LHSV of 1.20 hr ^-1 and methanol:phenol:water at a molar ratio of 5:1:1.41, the time required for activation was 15
It was time.

Comparative Example 2 A reaction was carried out in the same manner as in Example 3 except that water was not used for the activation treatment of the catalyst, and the time required for activation was 25 hours.

Claims (1)

[Claims] 1 In a method for producing alkylphenols by reacting phenols having at least one hydrogen atom on an aromatic ring with alcohols, magnesium and/or manganese oxides are treated with phenols or Catalyst containing magnesium phenolate from 300℃ to 700℃
A method for producing alkylphenols, which comprises using as an alkylation catalyst an alkylphenol treated with a steam-containing gas under the following temperature conditions.