JPS6293244A - Production of 1-bromo-4-fluorobenzene - Google Patents

Abstract

PURPOSE:The gas-phase bromination of fluorobenzene is effected in the presence of a catalyst containing copper with hydrogen bromide and oxygen to produce the title compound which is used as an intermediate of functional polymers in high selectivity. CONSTITUTION:The gas-phase bromination of fluorobenzene is carried out in the presence of a copper-containing catalyst such as metallic copper, copper chloride, copper bromide or copper sulfate using hydrogen bromide and oxygen to produce 1-bromo-4-fluorobenzene. Especially, a catalyst a catalyst supporting metallic copper or a copper compound and/or an ion-exchanged zeolite (especially Y-type zeolite) is preferred. The reaction temperature is the one at which the reaction system can be kept gaseous, preferably 150-250 deg.C. EFFECT:Elementary bromine is efficiently utilized.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention provides 1-
The present invention relates to a method for producing bromo-4-fluorobenzene.

(Prior art) Regarding the production method of 1-bromo-4-fluorobenzene, there is a method in which a Lewis acid such as antimony pentachloride or aluminum chloride is used as a catalyst when fluorobenzene and bromine are reacted in the liquid phase [Plutenopelement]. The Chemical Industry of Japan (Bullutin)
), 47.147 (19741), and a method using solid acids such as zeolite [Journal Op Catalysis (J, Catal, ), 60.110 (1979)
)It has been known. Furthermore, regarding the method of reacting fluorobenzene and bromine in the gas phase, it is known that the reaction proceeds without a catalyst at high temperatures of 200C or higher [Journal Opza Chemical Research (J, Ch.
em, Soc, ).

1957.1825-9]6 However, there is no known method for oxidatively brominating fluorobenzene using hydrogen bromide.

(The invention is still trying to solve the problem) The reaction between fluorobenzene and bromine generates hydrogen bromide as a product, and this hydrogen bromide does not work as a brominating agent, so it is not an effective use of elemental bromine. There was a problem with the law.

(Means for Solving the Problems) The present inventors investigated a method of oxidatively brominating fluorobenzene with hydrogen bromide and oxygen as an effective method of utilizing bromine, and found that a catalyst containing copper The present inventors have discovered that 1-bromo-4-fluorobenzene can be produced with good selectivity by reacting fluorobenzene with bromine and oxygen in the gas phase in the presence of 1-bromo-4-fluorobenzene, and have completed the present invention.

That is, the present invention provides oxidative bromination of fluorobenzene using hydrogen bromide and oxygen to produce 1-bromo-4-fluorobenzene in the gas phase in the presence of a copper-containing catalyst. The present invention provides a method for producing 1-bromo-4-fluorobenzene, characterized in that the reaction is carried out.

Examples of copper-containing catalysts used in the present invention include copper metals, chlorides such as chloride steel, bromide steel, and iodide steel; various copper salts such as nitrate steel, acetate steel, and sulfate steel; Examples include various copper compounds such as copper and oxides such as cupric oxide.
It is thought that at least a portion of these copper metals or copper compounds function as bromides in the reaction system and function as catalysts.

Therefore, the initial state of copper in the catalyst is not particularly limited, but bromide steel is preferred.

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

Further, as an effective catalyst in the present invention, ion-exchanged zeolite with copper ions 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, so it is preferably at least 5% of the ion exchange capacity of the zeolite, more preferably at least 10%. Note that the ion exchange capacity referred to here is the total capacity of the cation sites that form a pair with the anion sites of zeolite, hto;. Preferred zeolites in the present invention include Y-type zeolite, zegenite, ZSM-5, etc., and Y-type zeolite is particularly preferred.

The molar ratio of fluorobenzene/hydrogen bromide as raw materials in the present invention ranges from 0.1 to 100, preferably from 0.5 to 50, and more preferably from 1 to 10.

The molar ratio of oxygen/hydrogen bromide in the present invention is 0.01 to 2
0, preferably 0.1 to 10, more preferably 0.5
It is in the range of ~5. Further, oxygen is supplied alone or diluted.

The reaction temperature in the present invention is not particularly limited as long as the reaction system can be maintained in the gas phase, but if the temperature is too high, 1,
Due to isomerization of 4-unit, 1,2-unit and 1.3-unit by-products increase, so the temperature is usually 60 to 400 C, preferably 100 to s o o C, more preferably 150 to
It is in the range of 250C.

The pressure in the present invention may be reduced pressure, normal pressure, or increased pressure, but is usually 0.5 to 10 atms, preferably 0.
It is carried out in the range of 8 to 5 atm.

(Effect of the invention) 1-Bromo-4 that effectively utilizes bromine element according to the present invention
- It becomes possible to produce fluorobenzene, which means that
This is very advantageous for industrial implementation.

(Examples) Example 1 An oxybromination reaction of fluorobenzene was carried out under the following conditions using Cu-Y type zeolite (Cu''+ ion exchange rate = 65%, Na+-55%) as a catalyst.

Fluorobenzene/HBr10□/N7 molar ratio = 2/1
/1/3, reaction temperature 200 C, WH8V (based on fluorobenzene) wlohr-', pressure: normal pressure.

The results at VL 2 to 3 hours after the start of the reaction were: fluorobenzene conversion rate = 50%, bromofluorobenzene selectivity -, 9
8%, proportion of 1.4 monomer in bromofluorobenzene =
It was 95chi.

Example 2 Oxybromination reaction of fluorobenzene was carried out under the following conditions using a catalyst in which CuBr2 was supported on Y-type zeolite (Cu supported amount (relative to the carrier) - 20 weight).

Fluoropenzea/HBr10. IN,,,L5/1/
1.5/6, reaction temperature 16 DU, WHS V
-5, Ohr', normal pressure.

The results 9 to 10 hours after the start of the reaction are fluorobenzene E.
conversion rate -62%, selectivity of phamofluorobenzene: 99, ratio of 1.4 monomer in bromofluorobenzene = 96
%Met.

Example 3 An oxybromination reaction of fluorobenzene was carried out under the following conditions using Cu-mordenite (Cu''+ ion exchange rate = -70, H-30%) as a catalyst.

Fluorobenzene/HBr/01/Nz-
5/1/115, reaction temperature 250 C% WHS V
-8hr-'.

Pressure crab normal pressure.

The results 6 to 7 hours after the start of the reaction were: fluorobenzene conversion rate -3os, fluorofluorobenzene N selectivity rate -97
1. Ratio of 1,4 monomer in bromofluorobenzene = 9
4 I was disappointed.

Example 4 Oxybromination reaction of fluorobenzene was carried out under the following conditions using a catalyst in which CuBrl was supported on various carriers.

Fluoropenzey/HBr 10. IN,=2/
1/1/4, reaction temperature 200 C, WHS V −
5, Ohr-'.

Pressure crab normal pressure.

Table IK shows the results 3 to 4 hours after the start of the reaction.

Table 1 Example 5 Using CuO as a catalyst, oxybromination reaction of fluorobenzene with hydrogen bromide was carried out under the following conditions.

Fluorobenzene/HBr/Ox = 6/
1/1, reaction temperature 250 C, WHS v-a
1.0hr-', normal pressure.

The results 2 to 3 hours after the start of the reaction were: fluoropen-4i conversion rate -ta%, fluoropene-abenzene selectivity -9
Coordination 8, proportion of 1.4 units in bromofluorobenzene -
It was 95%.

Example 6 Y-type zeolite was immersed in a 20% copper nitrate aqueous solution, evaporated to dryness, and further calcined in air at 400C for 4 hours.
The Y-type zeolite supporting CuO is exactly the same. moreover,
This catalyst was reduced to 4501:: in a hydrogen stream for 4 hours to obtain a Y-type zeolite supporting metallic copper. The amount of metal steel supported was 11 weight units.

Using this catalyst, oxybromination reaction of fluorobenzene with hydrogen bromide was carried out under the following conditions.

Fluoropenzea/HBr10. IN, = 5/1
/ 1/4, reaction temperature 23 D C% WHS V -2
, Ohr-'.

Pressure crab normal pressure.

The results 2 to 3 hours after the start of the reaction were fluorobenzene conversion rate = 15% and bromofluorobenzene selectivity III! 9
9%, proportion of 1,4 monomer in bromofluorobenzene =
It was 95%.

Claims (3)

[Claims] (1) In producing 1-bromo-4-fluorobenzene by brominating fluorobenzene using hydrogen bromide 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.