JPS6153234A - Industrial production of p-halogenated bromobenzene - Google Patents

Abstract

PURPOSE:To produce a p-halogenated bromobenzene, in high selectivity, in an industrial scale, by brominating a halogenated benzene using a small amount of a Y type zeolite in the absence of solvent, at a temperature within a specific range. CONSTITUTION:A halogenated benzene is brominated in the presence of a Y type zeolite to obtain a p-halogenated bromobenzene. The bromination is carried out by mixing 1mol of the halogenated benzene with 0.01-10g of a Y type zeolite in the absence of solvent, introducing a brominating agent, and reacting at a temperature above 60 deg.C and below the boiling point of the reaction mixture, preferably <=200, especially <=100 deg.C. USE:Raw material for the production of pharmaceuticals, agricultural chemicals, etc.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a method for producing P-halogenated promobenzene, which is used as a raw material for producing medicines, agricultural chemicals, etc. The present invention relates to a method for industrially producing P-halogenated promobenzene with good selectivity by brominating halogenated benzene using zeolite.

(Prior art) As a method for producing P-halogenated promobenzene by brominating halogenated benzene in the presence of Y-type zeolite, 10 Y-type zeolite is used per mole of halogenated benzene.
A method is known in which bromine is reacted with 00 g of bromine in a solvent in the presence of sodium hydrogen carbonate and zeolite KA at a reaction temperature of 25°C.
taxis+ Volume 60 Pages 110-120 (19
(1979)) (Problems to be Solved by the Invention) In the prior art described above, it is possible to produce P-halogenated promobenzene with high selectivity, but it is possible to produce P-halogenated promobenzene with high selectivity, but it is not possible to react with bromine at a reaction temperature of 25°C. In this reaction process, hydrogen bromide, which is produced as a by-product, is adsorbed onto the Y-type zeolite and reduces the activity of the catalyst, so it is necessary to use a large amount of sodium hydrogen carbonate as a scavenger for hydrogen bromide. Because water is produced in the reaction with hydrogen bromide,
It is necessary to use zeolite KA as a dehydrating agent, and since this alone cannot sufficiently prevent a decrease in catalyst activity, it is necessary to use 1000 g of Y-type zeolite as a catalyst per 1 mole of promobenzene. Ta.

There is even a description that reducing the amount of catalyst reduces the selectivity of the two bodies. Furthermore, since a large amount of A is used in the Y-type zeolite hydrogen bromide scavenger sodium hydrogen carbonate and the dehydrating agent zeolite, it is necessary to carry out the reaction in a solvent. As mentioned above, in addition to a large amount of catalytic Y-type zeolite, a large amount of hydrogen bromide scavenger (hydrogen carbonate), dehydrating agent (zeolite), and reaction solvent are used, so P-dihalogenation can be carried out economically and industrially. It was not suitable as a method for producing benzene.

(Means for Solving the Problems) In view of the current situation, the present inventor has conducted extensive research in order to provide a method for industrially producing P-halogenated promobenzene, and as a result has unexpectedly discovered the following. We have found that the conventional problems can be solved by carrying out bromination in the absence of a solvent, using 0.01 to 10 g of Y-type zeolite per mole of halogenated benzene, at a temperature range of 60'C or higher and below the boiling point of the reaction mixture. Based on this finding, we have completed the present invention.

Examples of the halogenated benzene used as a raw material in the method of the present invention include chlorobenzene, promobenzene, fluorobenzene, and iodobenzene.

In addition, the Y-type zeolite used as a catalyst contains silicon oxide (
It is a crystalline aluminasilicate with a SiO□)/aluminum oxide (A1203) molar ratio of 4 to 7, and generally any synthetic zeolite or natural zeolite that has the same X-ray diffraction spectrum as that is sufficient. The ion-exchangeable cation contained in the zeolite is usually sodium or potassium, but other cations,
Examples of such cations include those from Group IA, Group IIA, Group IIIA of the periodic table, rV
Mention may be made of ions or protons of metals of group A, group VA, transition metals or ammonium. One type of these cations may be inserted, or two or more types may be included.

The amount of Y-type zeolite used is 1 1 of the raw material halogenated benzene.
o, oi to 10 g per mole.

To carry out the bromination of halogenated benzene according to the method of the present invention, 0.01 to 10
Y-type zeolite is mixed in a proportion of 1.5 g, and the brominating agent is introduced while stirring without solvent.

The reaction temperature at this time is 60°C or higher, below the boiling point of the reaction mixture, preferably 200°C or below, more preferably 100°C or below.If the reaction is carried out below 60°C, the reaction will not proceed smoothly. The purpose of the invention cannot be achieved. Bromine, N-bromosuccinimide and the like are used as the brominating agent in the present invention, but bromine is particularly preferred. These can also be used after being diluted with an inert gas such as nitrogen, if desired. The above reaction may be carried out either under reduced pressure or increased pressure, but it is usually carried out at normal pressure. After the reaction, the reaction mixture is post-treated by a conventional method such as catalytic filtration or distillation to produce P-halogenated promobenzene. can be obtained in high yield.

(Operation of the invention) According to the method of the present invention, adsorption of hydrogen bromide, which inactivates the catalyst, can be prevented by performing the reaction by selecting a specified temperature range. Not only is it unnecessary to add sodium bicarbonate, a hydrogen bromide scavenger to prevent hydrogen adsorption to the catalyst, and A in zeolite, which is added for dehydration, but the amount of Y-type zeolite added is also 1 mole of promobenzene. against 0. ．． This method is very suitable as a method for selectively producing P-halogenated promobenzene industrially, since only a small amount of 0.01 to 10 g is required, and the catalyst can be reused.

(Example) Next, the present invention will be explained in more detail with reference to Examples.

Example 1 200m1 equipped with cooling tube, thermometer, stirrer and blowing tube
Add 5 g of Y-type zeolite (trade name LZ-) to the reaction flask.
YB2. UNION CARBIDE C0RP,
157.0 g (1.0 mol) of promobenzene was added, and the mixture was stirred at 70° C. for 30 minutes under a Nt stream. Subsequently, bromine was added dropwise at 0.25 mol/hour over 4 hours. After the reaction was completed, the reaction solution obtained was analyzed by gas chromatography, and the reaction rate of promobenzene was 76.2%.
〇-dipromobenzene/P-dipromobenzene ratio is 0.
137, and the selectivity of P-dipromobenzene is 95.
It was 0%.

The Y-type zeolite used in the reaction had the following chemical composition (as determined by atomic absorption spectrometry).

S80□ (wt%) Dry base 76.9% Al
z 03(” ) ” 22.3%
NazO(” )” 0.12%(
NH4)20(”)
3. 86%SiO□/A 1gos molar ratio
5.86 Example 2 The reaction was carried out in the same manner as in Example 1 except that the reaction temperature was changed. The results are shown in Table -■.

Table - ■ Example 3 112.6g of chlorobenzene instead of promobenzene
The reaction was carried out in the same manner as in Example 1, except that the reaction rate of chlorobenzene was 80.9%, and the 0-bromochlorobenzene/P-bromochlorobenzene ratio was 0.051.
and the selectivity of P-bromochlorobenzene is 95.0
%Met.

Example 4 96.1 g of fluorobenzene instead of promobenzene
The reaction was carried out in the same manner as in Example 1, except that the reaction rate of fluorobenzene was 96.1%, and the 0-bromofluorobenzene/P-bromofluorobenzene ratio was 0.
029, and the selectivity of P-bromofluorobenzene was 97.2%.

Claims (1)

[Claims] In the method of producing P-halogenated promobenzene by brominating halogenated benzene in the presence of Y-type zeolite, 0.0.
An industrial method for producing P-halogenated promobenzene, characterized in that the reaction is carried out using 01 to 10 g of Y-type zeolite at a temperature range of 60°C or higher and lower than the boiling point of the reaction mixture.