KR830001290B1 - Catalyst for Nucleochlorination of Alkylbenzene - Google Patents

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Description

Catalyst for Nucleochlorination of Alkylbenzene

The present invention relates to a catalyst for nucleation excellent in selectivity to the p-position of alkylbenzene.

Nucleochlorinated compounds of alkylbenzenes are useful as raw materials for various organic synthetic chemistries including medicines and pesticides, but in particular, the amount of p-chloro-alkylbenzenes such as p-chlorotoluene is high.

However, in the conventional method of chlorination with chlorine gas using Lewis acids such as antimony chloride, ferric chloride, and aluminum chloride, which are generally performed chlorination reactions, o-chloroalkylbenzene is mainly produced. In addition, m-chloro and polychlorinated substituents are byproducts, and p-chloroalkyl benzene cannot be produced in a yield of 40% or more.

Thus, various catalysts have been developed for producing high yield of p-chloroalkylbenzene.

For example, in a method using Lewis acid and sulfur or selenium as a catalyst, p-chloro is obtained in a yield of 45 to 52%, and in the method using Lewis acid and thianslene as a catalyst, p-chloro is 55 Obtained with a yield of -60% (Japanese Patent Laid-Open No. 52-19630).

Iris acid and thialslen as catalysts can be said to have a very good selectivity to the p-phase, but this thianslen compound is oxidized in the presence of water and passes through 5, 5-dioxythianeslens, When diphenyl sulfides are used repeatedly, there are problems such as deterioration of catalytic activity and byproducts of chlorolation of side chain alkyl groups.

The present inventors have intensively studied to develop a catalyst having excellent selectivity to the p-phase and also having no problems with the thianslen compound. As a result, when the Lewis acid and phenoxanthine compound are used as catalysts, The phenoxanthin compound having excellent selectivity stops with 10-oxyphenoxanthin even when it is oxidized due to the presence of water, and it is found that the catalytic activity is not lowered even after repeated use, and chlorination of the branched alkyl group does not occur. The present invention has been achieved.

루이스산 및

일반식That is, the present invention,

Lewis and

General formula

Nucleochlorination of alkylbenzenes with phenoxanthine compounds represented by (wherein X ₁ , X ₂ , X ₃ and X ₄ represent the same or different hydrogen atoms, electron withdrawing groups or electron donating groups, respectively) To provide a catalyst.

In the present invention, Lewis acid includes not only Lewis acid, which means synergism, but also metals or compounds which form Lewis acid during nucleating reaction or function as Lewis acid, for example, antimony, iron, tin, and the like. And metals such as lead, aluminum, molybdenum, tellurium, halides, moles of oxides, sulfides, carbonyl compounds, and the like thereof, and particularly preferred examples thereof include antimony trichloride, antimony tetrachloride, aluminum chloride, and antimony trifluoride. Ferric chloride, ferric chloride, antimony oxychloride, antimony trioxide, antimony tetraoxide, antimony pentoxide, tellurium tetrachloride, ferric oxide, lead sulfide, ferrous sulfide, ferric sulfide, molybdenum hexacarbonyl, Iron ventacarbonyl etc. are mentioned.

Moreover, in the phenoxatin compound represented by general formula (I), X <_1> , X <_2> , X <_3> and X <_4> are hydrogen atoms, an electron withdrawing group, or an electron donating group, These may be same or different, respectively. Here, examples of the electron withdrawing group include a chlorine atom, a bromine atom, a halogen atom such as a fluorine atom, an alkanoyl group such as an acetyl group, an aroyl group such as a benzoyl group, a nitro group, a sulfonyl group, a cyano group, and a trifluoromethyl group. As an electron donating group, an alkyl group, an alkoxy group, etc. are mentioned. Such phenoxatin compounds may be used alone or in combination. As the phenoxanthine compound, a halogen having a degree of substitution of 2.0 or more is particularly suitable, but even if the degree of substitution is lower than that, the nuclear substitution proceeds with halogen while being used for the halogenation reaction, and finally the degree of substitution becomes 2.0 or more. It is enough to use.

In the present invention, the Lewis acid and the phenoxatin compound are used in a molar ratio of 0.1 to 10: 1, preferably 0.25 to 4: 1.

Nucleochlorination of alkylbenzenes using the catalyst of the present invention comprises the presence of a catalyst at a rate of 0.001 to 5.0% by weight, preferably 0.01 to 1.0% by weight, of the amount of alkylbenzene in the total amount of the Lewis acid and the phenoxatin compound. Chlorine gas is introduced at a temperature below the boiling point of the reaction mixture. If the temperature is too high, the amount of polychloride produced is large, and the yield of p-chloro is reduced, which is not good. On the other hand, the reaction can be carried out even at a low temperature of 10 ° C or lower, and the selectivity of p-chloro is increased, but the reaction rate is slow and economical. Therefore, it is usually industrially at a temperature of 0 to 80 ° C. Is appropriately performed at a temperature of 20 to 70 ° C. The pressure of the chlorine gas may be any of normal pressure, pressure, and reduced pressure, but is usually reacted under normal pressure.

Examples of the alkylbenzenes nucleated using the catalyst of the present invention include benzene monosubstituted with various linear and branched alkyls, but particularly preferably those having 1 to 4 carbon atoms in the alkyl group.

When the catalyst of the present invention is used, chlorination of the alkylbenzene on the o-position can be suppressed and chlorinated efficiently on the p-position, and the formation of m-chloro and polychloride is extremely low. Moreover, even if it uses repeatedly, the catalyst of this invention is excellent in durability, excellent in durability, and suitable for industrially manufacturing p-chloro body of alkylbenzenes, such as toluene, and its industrial value is high.

Next, the present invention will be described in more detail with reference to the following Examples.

Example 1

Into a 1-four-necked flask equipped with a stirrer, a thermometer, a gas inlet pipe, and a reflux condenser, 480 g of cumene, 2 g of antimony trichloride, and 2 g of phenoxanthine were added, and the mixture was warmed to about 50 ° C. in a water bath while the temperature was kept constant. After that, chlorine gas is introduced at a rate of 300 ml / min, and the reaction temperature is maintained at 50 to 55 캜 in a water bath. The reaction was stopped by introducing chlorine gas for 5 hours, and the reaction solution was analyzed by gas chromatography. As a result, the composition of the produced monochloro cumene was 2-chloro cumene / 4-chloro cumene ratio (o / p) = 0.57.

Example 2

The reaction was carried out under the same conditions as in Example 1 except that 424 g of ethyl benzyl was used instead of cumene. As a result of analysis by the gas chromatograph method, the reaction liquid composition was 2-chloroethylbenzene / 4-chloroethylbenzene ratio (o / p) = 0.68.

Example 3

Halogenation was carried out under the same conditions as in Example 1 except for using toluene instead of cumene and changing the type and amount of catalyst.

The 2-chlorotoluene / 4-chlorotoluene ratio (o / p) in the product thus obtained is shown in a 1st table | surface.

[Table 1]

Reaction temperature 10-15 ℃

** reaction temperature 30 ~ 35 ℃

*** reaction temperature 40 ~ 45 ℃

Example 4

The reaction was carried out under the same conditions as in Example 1 except that 0.135 g of antimony trichloride, 0.135 g of 2, 3, 7, 8-tetrachloropheno chisarin was used to clarify the repeating effect of the catalyst. After the completion of the reaction, the toluene nucleochloride was isolated by distillation, and then toluene was added to the residue again, and the catalyst was repeatedly used. The results are shown in the second table.

As can be seen from this table, the reaction proceeded normally even at the sixth time of repeated use of the catalyst, the o / p ratio was 0.86 to 0.87, and no nucleated chloride was identified. In addition, 2, 3, 7, 8-tetrachloropheno chisatin in the residue after 6 repetitions was analyzed by gas chromatograph, and 2, 3, 7, 8-tetrachloropheno chisatin and 10-oxy- A mixture of 2, 3, 7, 8-tetrachloropheno chisatin, 52% of which was 2, 3, 7, 8-tettachloropheno chisatin. In addition, these totals were added initially. It was an amount equivalent to 2, 3, 7, 8-tetrachloropheno chisatin.

[Table 2]

[Comparative Example]

The chlorination reaction was carried out under the same conditions as in Example 4, except that 0.142 g of 2, 3, 7, 8-tetrachlorothiaxylene was used instead of 2, 3, 7, 8-tetrachlorophenochisatin. The results are shown in Table 3.

[Table 3]

Claims (1)

Lewis and

General formula

For nucleochlorination of alkylbenzenes of phenoxysatin compounds or mixtures thereof represented by X ₁ , X ₂ , X ₃ and X ₄ each representing the same or different hydrogen atoms, electron withdrawing groups or electron donating groups catalyst.