KR840001030B1 - Preparation of para chloro alkybenzene - Google Patents

Abstract

Title compds, useful as intermediates for organic synthesis, were prepd. by chlorinating of alkylbenzenes in the presence of a phenoxathiin I(R1-R4 independently=H, an electron-withdrawing group or an electron-donating group) and a Lewis acid or precursor as catalyst. Thus, passing Cl2 into a mixt. of toluene, SbCl3, and phenoxathiin at 50-55≰C and 300 ml/min gave nomo-chlorotoluene in 0.85-0.87 ortho-para ratio.

Description

Method for preparing alkyl benzene nucleide

The present invention relates to a process for the continuous production of nucleochlorides on p-selectivity of alkylbenzenes with good selectivity.

Nucleochlorides of alkylbenzenes are useful as raw materials for various organic synthetic chemistries, including medicines and pesticides. In particular, the demand amount of the nucleochloride on p- of alkylbenzenes, such as p-chlorotoluene, is large.

MEANS TO SOLVE THE PROBLEM The present inventors have already made the method of preparing the nucleochloride on p-position of alkylbenzene with good selectivity.

(Wherein X ₁ , X ₂ , X ₃ , and X ₄ each represent the same or different hydrogen atom, electron withdrawing group or emulsifying group)

A method of nucleating with chlorine in the presence of a catalyst consisting of a phenochisatin compound represented by

In this method, since the stability of the catalyst is good, it is possible to obtain a good yield by repeating the nucleation of alkylbenzene by 5 to 6 without adding or exchanging the catalyst. The selectivity of chlorination for the p- stomach worsens. This is indicated by the increase in the non-so-called o / p ratio of the o-top nucleochloride and the p-nucleochloride to the alkyl group of the alkylbenzene.

MEANS TO SOLVE THE PROBLEM As a result of earnestly researching in order to develop the method which the selectivity of the nucleus of p-position does not fall even if it repeats nucleochlorination of alkylbenzene again using the said catalyst, after carrying out nucleation, In the case where the residue containing the catalyst after separation of the desired product of chlorine by distillation or the like is treated with hydrogen halide, the alkyl benzene may be nucleated again using this catalyst. It has been found that p-chlorine can be produced at high yields without increasing the ratio, and the present invention has been made in accordance with transplant dogs.

That is, the present invention is an alkyl benzene Lewis acid and a general formula [I]

(Wherein X ₁ , X ₂ , X ₃ and X ₄ each represent the same or different hydrogen atom, electron withdrawing group or electron donating group).

Nucleochlorination in the presence of a catalyst consisting of a phenochisatin compound represented by In the continuous preparation of the nucleochloride of, to provide a method for producing a nucleated chloride of alkylbenzene characterized in that the catalyst is activated by introducing hydrogen halide to the residue containing the catalyst in any step.

Examples of the alkylbenzene to be chlorinated in the present invention include various linear and branched alkylbenzenes and substituted alkylbenzenes, but particularly preferably those having 1 to 4 carbon atoms in the alkyl group.

The Lewis acid used in the present invention includes not only Lewis acid in the usual sense but also a metal or compound which forms Lewis acid during nucleating reaction or functions as a Lewis acid, for example, antimony, iron, Metals such as tin, lead, aluminum, molybdenum, tellurium, halides, oxides, sulfides and carbonyl compounds thereof, and the like, and particularly preferred examples thereof include: trimonium trichloride, ferrous chloride and ferric chloride; Tellurium chloride, antimony oxychloride, antimony trioxide, antimony tetraoxide, antimony pentoxide, ferric iron oxide sulfide ferric sulfide, ferric sulfide, molybdenum hexacarbonyl, iron pentacarbonyl, and the like.

In addition, as the phenoxystatin compound represented by the general formula [I], X ₁ , X ₂ , X ₃ and X ₄ in the general formula [I] are hydrogen atom electron inhalable groups or electron donor groups, each of which is the same or Or may be different. Examples of the electron withdrawing group include an aloyl group, a titro group, a sulfonyl group, a cyano group, a trifluoromethyl group, and the like, such as an alkanoyl group and a benzoyl group, such as a halogen atom acetyl group such as a chlorine atom, a bromine atom, and a fluorine atom. As an electron-porous group, an alkyl group, an alkoxy group, etc. are mentioned.

In the present invention, the Lewis acid and the phenokisarin compound may be used alone or in combination.

In the present invention, in the nucleochlorination of alkylbenzene, the catalyst is present in a total amount of leunic acid and phenoxysatin compound in an amount of 0.001 to 5.0% by weight, preferably 0.01 to 1.0% by weight of the amount of alkylbenzene. The chlorinating agent is introduced at a temperature below the boiling point of the reaction mixture. If the temperature is too high, the amount of polychloride produced increases, and the yield of p-chloride decreases, which is unfavorable. The reaction can be carried out even at a low temperature of 1 pen or less than -10 ° C, and the selectivity of p-chlorine increases, but the reaction rate is slow and economical. Therefore, it is usually industrially at a temperature of 0 to 80 ° C. It is appropriate to carry out at the temperature of 70 degreeC. As the chlorinating agent at this time, commonly used chlorinating agents such as thionyl chloride and hypochlorite can be used, but chlorine gas is particularly preferable. When this chlorine gas is used, either pressure reduction or pressurization may be used, but usually at normal pressure.

In the present invention, activation of the catalyst is performed by introducing hydrogen halide at any stage into the residue containing the catalyst after the nucleated chlorine which is the desired product is separated, for example, by distillation or the like. Hydrogen fluoride, hydrogen chloride, hydrogen bromide etc. are mentioned as hydrogen halide used here. There is no restriction | limiting in particular in the introduction amount and introduction time of hydrogen halide, Preferably it is the range of 10 to 24 hours at 20-1000 ml / min.

In the present invention, a solvent is not particularly used in the nucleation reaction and activation of the catalyst, but an inert solvent may be used for the purpose of smoothly reacting, or alkylbenzene as a raw material may be used as the solvent. Moreover, in activating a catalyst, the alkylbenzene which should be chlorinated may remain.

In the present invention, the hydrogen halide used for the activation of the catalyst is very economical because hydrogen chloride which is a byproduct in the nucleation of alkylbenzene can be used.

According to the present invention, p-chloroalkylbenzene can be produced repeatedly with good selectivity, and production of m-chloro bodies and polychloro bodies can be extremely reduced. In addition, since the catalyst can be used repeatedly, not only can the catalyst amount of the produced p-chloroalkylbenzene sugar be significantly reduced, but also the amount of waste liquid and waste can be reduced, which is preferable in terms of waste treatment. The value is extremely high.

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

Example 1

To a 1 L four-necked flask equipped with a stirrer, a thermometer, a gas blowing tube, and a reflux condenser, 368 g of toluene, 0.1 g of antimony trichloride, and 0.14 g of 2,3,7,8-tetrachlorophenoxysarin were mixed and stirred while stirring Heated until it became 50 degreeC, chlorine gas was introduce | transduced at the rate of 300 ml / min, and it was made to react for 5 hours, keeping temperature at 50-55 degreeC. After completion of the reaction, distillation was carried out to separate the nucleated chloride of toluene, new toluene was added to the residue containing the catalyst, chlorine gas was introduced again, and the chlorination reaction was carried out as above. Thus, the chlorination reaction was repeated 6 times. After the nucleated toluene was separated from the sixth reaction mixture, hydrogen chloride was introduced at 100 ml / min for 1 hour while stirring the residue containing the catalyst and treated. Subsequently, toluene was newly added and the same chlorination reaction was repeated 7 times and 13 times in total again.

The produced monochlorotoluene had an o / p ratio of 0.85 to 0.87 no time, and no nucleated chloride was identified. In addition, after analyzing the residue after the sixth kind, 52% of the used 2,3,7,8-tetrachlorophenokistine was oxidized to 10-oxygen, but after treatment with hydrogen chloride, the 80% was 2%. It turned out that it was 3,7,8-tetrachloro phenoxysatin.

In addition, it was found that the absolute amount of 2,3,7,8-tetrachlorophenoxysatin did not change from the first to the 13th time, and was not subjected to chemical changes such as decomposition except being oxidized to a 10-oxygen. The chlorination reaction of toluene was repeated nine times in the same manner as in Example 1 except that the hydrogen chloride treatment was not performed before the seventh chlorination reaction.

The o / p ratio of the produced monochlorotoluene was 0.86 from the first to the sixth time, and there was no change of nucleated chloride, but the o / p ratio was 1.5 in the seventh time and a large amount of nucleated chloride was also detected. . After the ninth kind, only 10% of 2,3,7,8-tetrachlorophenokistine was present, and the rest was 10-oxygen.

Example 2

Chlorination of toluene was carried out in the same manner as in Example 1 except for changing the type of catalyst and the amount of catalyst. Hydrogen chloride treatment was also performed before starting the seventh reaction as in Example 1.

The results are shown in the first table.

[Table 1]

Example 3

A chlorination reaction of ethylbenzene was repeated 13 times in the same manner as in Example 1 except that 424 g of ethylbenzene was mixed instead of 368 g of toluene. Before performing the seventh reaction, hydrogen chloride treatment of the residue was carried out as in Example 1.

The produced monochloroethylbenzene had no O / P ratio of 0.60 to 0.64 at any time, and no nucleated chloride was identified.

Example 4

The cumene was chlorinated 13 times in the same manner as in Example 1 except that 480 g of cumene was mixed instead of 368 g of toloene. Before performing the seventh reaction, hydrogen chloride treatment of the residue was carried out as in Example 1. The produced monochloro cumene had an O / P ratio of 0.45 to 0.48 at any time, and no nucleated chloride could be confirmed.

Claims (1)

Alkylbenzenes with Lewis acids and general formula

Nucleochlorination in the presence of a catalyst of phenochisatin compounds represented by (wherein X ₁ , X ₂ , X ₃ and X ₄ each represent the same or different hydrogen atoms, electron withdrawing groups or electron donating groups), and then To the residue containing the catalyst at any stage of the continuous production of the alkyl chloride of the alkylbenzene by separating the desired product of the nucleated chloride and nucleating by adding a new alkylbenzene to the residue containing the catalyst A method for producing nuclear chlorination of alkylbenzene, comprising the step of introducing hydrogen halide.