JPH0625083B2 - Method for producing 1-bromo-4-fluorobenzene - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention is useful as an intermediate raw material for functional polymers.
It relates to a method for producing bromo-4-fluorobenzene.

(Prior Art) Regarding a method for producing 1-bromo-4-fluorobenzene, a method of using a Lewis acid such as antimony pentachloride or aluminum chloride as a catalyst when reacting fluorobenzene and bromine in a liquid phase [Bruten of The Chemical Society of Japan (Bullutin), 4
7 , 147 (1974)] or a method using a solid acid such as zeolite [Jeanal of Katalysis (J. Ca.
tal. ), 60 , 110 (1979)] is known. Also, regarding the method of reacting fluorobenzene and bromine in the gas phase, it is known that the reaction proceeds at a high temperature of 200 ° C. or higher without a catalyst [Journal of the Chemical Society (J. Chem. Soc.),
1957, 1823-9].

Further, regarding a method of oxidatively brominating fluorobenzene with bromine and oxygen, a method of brominating halogenated benzene with bromine and oxygen in an aqueous liquid containing iron or copper ions (JP-A-49- However, there are no examples using fluorobenzene as a raw material.

(Problems to be Solved by the Invention) In the above-mentioned reaction of fluorobenzene and bromine, bromine and equimolar hydrogen bromide are generated as a product, and the hydrogen bromide does not act as a brominating agent. There was a problem in terms of effective utilization rate. In that respect, the oxidative bromination method using bromine and oxygen is advantageous in terms of effective utilization of bromine as shown in the following formula.

However, the oxidative bromination method in the liquid phase, in the study of the present inventors, the reaction rate is slow, and because of the reaction in an aqueous liquid, there is a problem in terms of corrosion of the device,
It was found that it was not at the level of industrial implementation.

(Means for Solving Problems) The present inventors have studied a method for producing 1-bromo-4-fluorobenzene, which has a high reaction rate and little apparatus corrosion, and as a result, fluorobenzene was used with bromine and oxygen. When 1-bromo-4-fluorobenzene is produced by oxidative bromination by a reaction in the presence of a catalyst containing copper in the gas phase, the reaction rate is high and there is no equipment corrosion. The present invention has been completed and the present invention has been completed.

That is, according to the present invention, in producing 1-bromo-4-fluorobenzene by oxidatively brominating fluorobenzene using bromine and oxygen, the reaction is carried out in the gas phase in the presence of a catalyst containing copper. 1-bromo-characterized in that
A method for producing 4-fluorobenzene is provided.

Examples of the copper-containing catalyst used in the present invention include halides such as copper metal, copper chloride, copper bromide and copper iodide, various copper salts such as copper nitrate, copper acetate and copper sulfate, cuprous oxide, Various copper compounds such as oxides of cupric oxide can be mentioned, and it is considered that these copper compounds partially act as bromides in the reaction system to act as a catalyst. Therefore, the initial copper state of the catalyst is not particularly limited, but preferred is copper bromide.

These copper compounds can be used alone, but can also be used by supporting them on a carrier. In that case, examples of the carrier to be used include alumina, silica, silica-alumina, silica-titania, boria, silica-boria, magnesia, zeolite and the like. The amount to be supported is not particularly limited, but if it is too small, the activity is low and it is not sufficient, so it is preferably 0.5% by weight or more, and more preferably 1% by weight with respect to the carrier.

Further, as an effective catalyst in the present invention, a copper ion-exchanged zeolite can be mentioned. The amount of copper ions contained in the zeolite is not particularly limited, but if it is too small, the activity will be low, and therefore it is preferably 5% or more, more preferably 10% or more of the ion exchange capacity of the zeolite. The ion exchange capacity mentioned here is the total amount of cation sites paired with AlO ₄ ⁻ which is the anion site of zeolite. Preferred examples of the zeolite in the present invention include Y-type zeolite, mordenite, ZSM-5 and the like, and particularly preferable is Y-type zeolite.

The fluorobenzene / bromine molar ratio of the raw material in the present invention is in the range of 0.1 to 100, preferably 0.5 to 50, and more preferably 1 to 10.

The oxygen / bromine molar ratio in the present invention is in the range of 0.01 to 20, preferably 0.1 to 10, and more preferably 0.5 to 5. In addition, oxygen is supplied alone or diluted.

The reaction temperature in the present invention is not particularly limited as long as it is a temperature capable of maintaining the reaction system in the gas phase, but if it becomes too high, 1,
Due to the isomerization of the 4-form, by-products of the 1,2-form and the 1,3-form are increased, so that it is usually 60 to 400 ° C, preferably 100 to 300 ° C, more preferably 150 to 250 ° C.
Is the range.

The pressure in the present invention may be any of reduced pressure, normal pressure and increased pressure, but is usually 0.5 to 10 atm, preferably 0.8 to 5 atm.

(Effects of the Invention) The present invention enables the production of 1-bromo-4-fluorobenzene that makes effective use of bromine, which is very advantageous for industrial implementation.

(Example) Example 1 As a catalyst, Cu-Y type zeolite (Cu2 ⁺ ion exchange rate =
70%, Na ⁺ = 30%), and the reaction was carried out under the following conditions.

Fluorobenzene _{/ Br 2 / O 2 / N} 2 molar ratio = 4/1/1 /
4. Reaction temperature 200 ° C., WHSV (fluorobenzene standard) = 5.0 hr ⁻¹ , pressure = normal pressure.

2-3 hours after the start of the reaction, the fluorobenzene conversion rate is 35%, the bromofluorobenzene selectivity is 98%,
Proportion of 1,4-body in bromofluorobenzene = 96%
It was.

Example 2 A catalyst in which CuBr ₂ is supported on a Y-type zeolite (C to the carrier is
The supported amount of u was 25% by weight) and the reaction was carried out under the following conditions.

Fluorobenzene _{/ Br 2 / O 2 / N} 2 = 3/1 / 1.5 / 4,
Reaction temperature 220 ° C., WHSV = 8.0 hr ⁻¹ , pressure: normal pressure.

6 to 7 hours after the start of the reaction, the fluorobenzene conversion rate = 50%, bromofluorobenzene selectivity = 98%,
Proportion of 1,4-body in bromofluorobenzene = 95%
It was.

Example 3 As a catalyst, Cu-mordenite (Cu ₂₊ ion exchange rate = 6
5%, Na ⁺ = 35%), and the reaction was carried out under the following conditions.

Fluorobenzene / Br ₂ / O ₂ / N ₂ = 5/1/2/4, reaction temperature 250 ° C., WHSV = 9.0 hr ⁻¹ , pressure: normal pressure.

5 to 6 hours after the start of the reaction, the fluorobenzene conversion rate was 30% and the bromofluorobenzene selectivity was 97.5.
%, Ratio of 1,4-body in bromofluorobenzene = 9
It was 5%.

Example 4 As a catalyst, ZSM-5 carrying CuBr ₂ (Cu loading = 15 wt%) was used and a reaction was carried out under the following conditions.

Fluorobenzene / Br ₂ / O ₂ / N ₂ 2/1/1/4, reaction temperature 185 ° C., WHSV = 2.0 hr ^-1 , pressure: normal pressure.

After 3 to 4 hours from the start of the reaction, the conversion of fluorobenzene was 60%, the selectivity of fluorobenzene was 98%, and the ratio of 1,4-isomer in fluorobenzene was 94%.

Example 5 Using a catalyst in which CuBr ₂ was supported on various carriers, a reaction was carried out under the following conditions.

Fluorobenzene / Br ₂ / O ₂ / N ₂ = 4/1/1/4, reaction temperature 200 ° C., WHSV = 5.0 hr ⁻¹ , pressure: normal pressure.

The results of 4 to 5 hours after the start of the reaction are shown in Table 1.

Example 6 The Y-type zeolite was immersed in a 20% copper nitrate aqueous solution, evaporated to dryness, and further calcined in air at 400 ° C. for 4 hours to prepare a CuO-supporting Y-type zeolite. Further, this catalyst was subjected to reduction treatment in a hydrogen stream at 450 ° C. for 4 hours to obtain a Y-zeolite carrying metallic copper. The amount of metallic copper supported was 11% by weight.

Using this catalyst, the reaction was carried out under the following conditions.

Fluorobenzene / Br ₂ / O ₂ / N ₂ = 5/1/1/4, reaction temperature 250 ° C., WHSV = 3.0 hr ⁻¹ , pressure: normal pressure.

2-3 hours after the start of the reaction, fluorobenzene conversion rate = 14%, bromofluorobenzene selectivity = 99%,
Proportion of 1,4-body in bromofluorobenzene = 95%
It was.

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Claims (3)

[Claims] 1. When producing 1-bromo-4-fluorobenzene by brominating fluorobenzene with bromine and oxygen, the reaction is carried out in the gas phase in the presence of a catalyst containing copper. A method for producing 1-bromo-4-fluorobenzene. 2. The method according to claim 1, wherein the catalyst is a supported catalyst of copper metal or a copper compound and / or an ion-exchanged zeolite. 3. The method according to claim 2, wherein the zeolite is a Y-type zeolite.