JPH02250837A - Production of alkyl-substituting aromatic hydrocarbons - Google Patents

Abstract

PURPOSE:To employ, as a catalyst, a solid base which is prepared by heat- treating alumina, alkaline earth metal compounds and alkali metal in an inert gas atmosphere in the alkylation of an aromatic hydrocarbon bearing hydrogen atoms in the alpha-position on the side chain. CONSTITUTION:When the title substance such as t-amylbenzene is produced by alkylating an aromatic hydrocarbon having hydrogen atoms in the alpha-position of the side chain such as cumene with an olefin such as ethylene, a solid base which is prepared by heat-treating a mixture of alumina, 5 to 40wt.%, based on the alumina, of alkaline earth metal compound such as magnesium hydroxide and 2 to 15wt.%, based on the alumina, of an alkali metal such as potassium at 200 to 800 deg.C in an inert gas atmosphere. The catalyst shows markedly high alkylation activity to produce the objective substance efficiently with a reduced catalyst amount, the product can be readily separated and very easy to be handled, because there is no danger of ignition, even when the catalyst is exposed to air moisture.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a method for producing an alkyl-substituted aromatic hydrocarbon, and more particularly, to a method for producing an alkyl-substituted aromatic hydrocarbon. The present invention relates to a method for producing an alkyl-substituted aromatic hydrocarbon by reacting an aromatic hydrocarbon having a hydrogen atom at the α-position of the side chain with an olefin in the presence of the present invention to alkylate the α-position.

<Prior art> Alkyl-substituted aromatic hydrocarbons are useful as intermediate raw materials for fine chemicals such as agricultural products, pharmaceuticals, and chemical products. It can be obtained by reacting with lefin.

For example, a method using a catalyst consisting of metallic sodium and chlorotoluene as a catalyst, a method using a catalyst in which metallic sodium is supported on potassium carbonate, etc. are known (J,
^m, chem, soc,, 78.4316 (1956
), British Patent No. 1269280, JP-A-61-532
Publication No. 29).

<Problems to be Solved by the Invention> However, when the above-mentioned catalyst is used, there are problems such as insufficient catalytic activity and a low yield of alkyl-substituted aromatic hydrocarbons per catalytic light; There are problems in that the separation of substances is complicated, and furthermore, there is a problem in that the catalyst is easily deactivated when it comes into contact with air or moisture in the atmosphere, and there is a risk of ignition.

<Means for Solving the Problems> The present inventors have conducted intensive studies on alkylation catalysts in order to develop an excellent method for producing alkyl-substituted aromatic hydrocarbons by alkylating the α-position of aromatic hydrocarbons. result,
A specific solid base obtained by heat treating alumina, an alkaline earth metal compound, and an alkali metal exhibits extremely high alkylation activity, and can efficiently produce the desired alkyl-substituted aromatic hydrocarbon with a small amount of catalyst. However, it was found that the solid base can be easily separated from the reaction product, and that there is little risk of ignition even when it comes into contact with atmospheric air or moisture, and that it is extremely easy to handle. After further study, the present invention was completed.

That is, the present invention uses alumina, an alkaline earth metal compound, and an alkali metal as a catalyst when alkylating an aromatic hydrocarbon having a hydrogen atom at the α-position of the side chain with an olefin to produce an alkyl-substituted aromatic hydrocarbon. The present invention provides an industrially excellent method for producing alkyl-substituted aromatic hydrocarbons, which is characterized by using a solid base obtained by heat treatment at a temperature of 200 to 800°C in an inert gas atmosphere.

The present invention is characterized by using a solid base obtained by heat-treating alumina, an alkaline earth metal compound, and an alkali metal at a specific temperature.
Various forms other than alumina can be used, among them T
Alumina having a large surface area, such as -1χ-1ρ- type, is preferably used.

In preparing the solid base, it is preferable to heat alumina first with an alkaline earth metal compound and then with an alkali metal under an inert gas atmosphere.

As an alkaline earth metal compound, for example,
Examples include oxides, hydroxides, and alkoxides of group elements, but oxides and hydroxides of magnesium, calcium, barium, etc. are preferable. Two or more kinds of alkaline earth metal compounds can also be used. The amount used is usually 5 to 40 wt% based on alumina.

The alkaline earth metal compound is usually used in the form of a solution in water, an organic solvent, or the like, or a finely dispersed suspension.

When acting on alumina, the solution or suspension may be added to the alumina stirred at a predetermined temperature, or the solution or suspension may be used to support the alkaline earth metal compound on the alumina in advance. After this, heating may be applied.

Also, examples of alkali metals include lithium, which is in group II of the periodic table;
Alkali metals such as sodium, potassium and rubidium are used, preferably sodium, potassium or a mixture thereof, and more preferably potassium.

The amount of alkali metal used is usually 2 to 15 per alumina.
−tχ.

Examples of the inert gas include nitrogen, helium, and argon.

The catalyst preparation temperature is important, usually 200 to 800°C,
Preferably, the temperature at which the alumina and the alkaline earth metal compound are allowed to react is 250 to 600°C, and the temperature at which the alkali metal is allowed to react is preferably 200 to 450°C.

The heating time depends on the selected temperature conditions, etc., but the process of allowing the alkaline earth metal compound to act usually takes 0.5 to 10 minutes.
Time is sufficient, and the step of exposing the alkali metal usually takes 10 to 300 minutes.

In this way, a solid base is obtained which is highly active, has good fluidity and operability, and has no risk of ignition even when exposed to air.

The present invention uses such a solid base to react an aromatic hydrocarbon having hydrogen at the α-position of the side chain with an olefin. , a fused polycyclic aromatic hydrocarbon is used. The side chains may be combined to form a ring.

For example, toluene, ethylbenzene, isopropylbenzene, n-propylbenzene, n-butylbenzene, 5e
e-butylbenzene, isobutylbenzene, xylene,
Cymene, diisopropylbenzene, methylnaphthalene,
Examples include tetrahydro-naphthalene and indane. Toluene, ethylbenzene and isopropylbenzene are preferably used.

Further, as the olefin, an olefin having 2 to 20 carbon atoms is usually used, and it may be either a straight chain or a branched olefin, and it can be used even if the double bond is at the terminal or internally. Terminal olefins are preferably used.

Specific examples of these compounds include ethylene, propylene, 1-butene, 2-butene, isobutylene, 1-pentene, 2-pentene, 1-hexene, 2-hexene,
3-hexene, 1-heptene, 2-heptene, 3-heptene, octene, nonene, 3-methyl-1-butene, 2
-Methyl-2-butene, 3-methyl-1-pentene, 3
-methyl-2-pentene and the like. ethylene,
Propylene, 1-butene, 2-butene are preferably used.

In carrying out the alkylation reaction, batch method,
Both distribution systems using fluidized beds and fixed beds can be adopted.

The reaction temperature is usually 0 to 300°C, preferably 20 to 200°C.
00°C, and the reaction pressure is usually atmospheric pressure to 200Kg.
/c■8, preferably 2 to 100) [g/cm".

The molar ratio of olefin to aromatic hydrocarbon is usually 0.1 to 10, preferably 0.2 to 5.

The amount of catalyst used in the batch process is usually 0.00% of the aromatic hydrocarbon used. tl to 20w tl, preferably 0
．． 05 to 5wtχ, and the reaction is usually 0.5 to 50
time, preferably 1 to 25 hours. In addition, the total feed rate of aromatic hydrocarbons and aliphatic olefins in the flow reaction is usually 0.1 to 1000 hr-' at LHSV.
, preferably 0.5 to 500 hr-'.

<Effect of the invention> In this way, alkyl-substituted aromatic hydrocarbons are produced,
According to the present invention, target alkyl-substituted aromatic hydrocarbons can be produced extremely efficiently with a small amount of catalyst and even under mild conditions.

In addition, the process of the invention is advantageous in this respect as not only the handling of the catalyst but also the post-reaction work-up is extremely convenient.

<Example> The present invention will be explained in more detail with reference to Examples below.
The present invention is not limited only to these examples.

Catalyst Preparation Example (Solid Base A) 26.5 g of activated alumina (NKHD-24, manufactured by Sumitomo Chemical Co., Ltd.) arranged in a mesh size of 42 to 200 was added to a solution consisting of 2.5 g of magnesium hydroxide and 50 g of water, and then this was mixed with approx. It was evaporated to dryness at 70°C under reduced pressure using a rotary evaporator.

This was stirred for 2 hours at 500°C under a nitrogen atmosphere, and then for 2 hours.
After cooling to 90°C, 2.0 g of metallic potassium was added and stirred at the same temperature for 0.2 hours. This was allowed to cool to room temperature to obtain 26.2 g of solid base A.

(Solid Base B) Solid base A was prepared according to the preparation example of solid base A except that calcium hydroxide was used instead of magnesium hydroxide, and 27.5 g of solid base B was obtained.

(Solid Base C) Solid base A was prepared in accordance with the preparation example of solid base A, except that barium hydroxide was used instead of magnesium hydroxide, and 27 g of solid base C was obtained.

(Solid base D) Solid base A was prepared in accordance with the preparation example of solid base A, except that magnesium oxide was used instead of magnesium hydroxide, and 26.8 g of solid base was obtained.

Example 1 0.43 g of solid base A and 240 g of cumene were placed in a 600 d autoclave equipped with a magnetic stirrer under a nitrogen atmosphere.
After raising the temperature to 160° C. with stirring at 000 r, p, m, the reaction was carried out for 3 hours at the same temperature while supplying ethylene gas at 10 kg/cm”·G.

After the reaction, the autoclave was cooled, the catalyst was filtered off, and the reaction solution was analyzed by gas chromatography. The reaction results are shown in Table 1.

Example 2 In Example 1, 0.48 g of solid base A was used to prepare 1
Table 1 shows the results of the 0 reaction carried out in accordance with Example 1 except that the reaction was carried out at 00°C.

Examples 3-5 In Example 1, solid base B was substituted for solid base A,
Example 1 using C and D, respectively, except for the conditions shown in Table 1.
Table 1 shows the results of the 0 reaction carried out in accordance with the above. still,
In Examples 1 to 5, the catalyst was still active after the reaction was completed, and when the reaction was further carried out, the reaction proceeded.

Comparative Example 1 8.19 g of anhydrous potassium carbonate and 0.30 g of sodium were calcined in advance at 400°C for 2 hours in a 200 gf autoclave with a magnetic stirrer under a nitrogen atmosphere.
After adding 26.7 g of cumene and 26.7 g of cumene, the temperature was raised to 190'C, and stirring was continued at 1000 r, p, m for 2 hours at the same temperature.

Next, the autoclave was cooled, and after adding 53.3 g of cumene, the temperature was raised to 160 °C under stirring at 1000 r, p, a+, and the reaction was continued at the same temperature for 3 hours while supplying ethylene gas at 10 kg/cm'G. went. Table 1 shows the reaction results.
It was shown to.

TAB s tart-amylbenzene Example 6 300ij with magnetic stirrer! Put 2.86 g of solid base A and 80 g of toluene into an autoclave under a nitrogen atmosphere,
After pressurizing liquefied propylene 70Id, 164°C, 1
The reaction was continued for 6 hours under stirring at 000 r, p, m.

After the reaction, it was analyzed by gas chromatography in the same manner as in Example 1. The results are shown in Table 2.

Examples 7-9 In Example 6, instead of solid base A, solid base B,
Example 6 using C and D, respectively, except for the conditions shown in Table 2.
Table 2 shows the results of one reaction carried out in accordance with the above. still,
In Examples 6 to 9, the catalyst was still active after the reaction was completed, and when the reaction was further carried out, the reaction proceeded.

Comparative Example 2 200mj with TL magnetic stirrer under nitrogen atmosphere! After adding 8.45 g of anhydrous potassium carbonate, 0.30 g of sodium, and 26.6 g of toluene, which had been calcined for 2 hours under a 400" C1 nitrogen atmosphere, to the autoclave, 190"
'c for 2 hours 1000r.

Stirring was continued at p, m.

Then, the autoclave was cooled and 53.2 g of toluene was added.
After adding 70 att of liquefied propylene, 1
The mixture was stirred at 60°C for 6 hours.

The results are shown in Table 2.

1BB-isobutylbenzene

Claims (1)

[Claims] When producing an alkyl-substituted aromatic hydrocarbon by alkylating an aromatic hydrocarbon having a hydrogen atom at the α-position of the side chain with an olefin, alumina, an alkaline earth metal compound, and an alkali metal are used as catalysts in an inert gas atmosphere. ,
A method for producing an alkyl-substituted aromatic hydrocarbon, which comprises using a solid base that is heat-treated at a temperature of 200 to 800°C.