JPS6293242A - Production of p-dibromobenzene - Google Patents

Abstract

PURPOSE:In the gas-phase oxidative bromination of benzene or brombenzene using bromine or a combination of hydrogen bromide and oxygen, a Y-type zeolite bearing metallic copper and/or copper compounds is used as a catalyst to obtain the title compound in high selectivity. CONSTITUTION:A Y-type zeolite supporting more than 5wt%, preferably 5-200wt%, particularly 15-100wt% of metallic copper and/or copper compounds, calculated as copper element, is used as a catalyst to effect gas- phase oxidative bromination of benzene and/or brombenzene at a molar ratio of 0.5-5.0, preferably 0.8-3.0 (a) bromine and/or hydrogen bromide to (b) oxygen whereby p-dibromobenzene which is used as an intermediate of p- penylenediamine (a starting material for aramide fibers) or other material for various heat-resistant resin. The process can high reaction selectivity and the content of the p-isomer exceeds 80% with industrial advantage.

Description

Detailed Description of the Invention (Field of Industrial Application) Himi FJA relates to a method for producing para-dibromobenzene, which is useful as an intermediate raw material for para-phenylenediamine, which is a raw material for aramid fibers, and as a raw material for various heat-resistant resins. .

(Prior art) Paradibromobenzene is produced by brominating benzene or brombenzene in the liquid phase in the presence of a Lewis acid catalyst such as iron bromide or aluminum bromide (Feuser Bottle New Organic Chemistry 1). ■Page 47), or a method of oxidative bromination using bromine and oxygen in the presence of an aqueous solution containing iron ions or copper ions in a liquid phase of benzene or bromobenzene (Japanese Unexamined Patent Publication No. 49-20126). No.) is known.

(Problems to be Solved by the Invention) The bromination method using bromine using the Lewis acid described above has a low proportion of para-isomer in dibromobenzene of 60 to 70%, and para-dibromobenzene is useful as an intermediate raw material. The manufacturing method was not satisfactory. Furthermore, regarding the method of oxidative bromination using bromine and oxygen in the presence of an aqueous solution containing iron or copper ions, there is no data regarding the proportion of loose bodies in dibromobenzene, and this researcher et al. According to the results of the study, the percentage of caries was 60.
It was found to be as low as ~70%.

Means for Solving Problem C) As a result of intensive studies to solve these problems, the present inventors used Y-type zeolite supporting metal copper and/or copper compounds as a catalyst, and It was discovered that by oxidatively brominating bromine and /lfc in the phase with hydrogen bromide and oxygen, para-dibromobenzene can be obtained with high selectivity, with a proportion of loose bodies in dibromobenzene of 80 or more. , we have completed the present invention.

In other words, the present invention provides a process for producing paradibromobenzene by oxidatively brominating benzene, bromobenzene, or both in a gas phase using bromine, hydrogen bromide, or both, and oxygen. , is a method for preparing puffed dibromobenzene, which is characterized by using Y-type zeolite supporting metallic copper and/or a copper compound as a catalyst.

The Y-type zeolite used in the present invention has a crystal structure generally called faujasite, and has a crystal structure of S io, /
A40. (molar ratio) is a zeolite of 4 to 6.

The copper element in the catalyst used in the present invention includes metallic copper and/or
Alternatively, it is supported on Y-type zeolite in the form of various compounds. Examples include metallic copper, oxidized steel, copper halide, nitrate steel, sulfuric acid steel, copper acetate, etc. In the reaction system, these metallic copper and copper compounds are at least partially catalyzed in the form of bromide steel. Therefore, it is preferable to support gA bromide.

The amount of metallic copper and/or copper compound supported in the catalyst in the present invention is not particularly limited, but if it is too small, the activity will be low, so it is preferable that the amount of copper element supported is 5 to 200% by weight relative to the Y-type zeolite support. f%, more preferably 15-100
It is within the range of heavy attack.

Moreover, although the Y-type zeolite that is a carrier contains cations in its crystal structure, there is no particular restriction on the type of cation in the Y-type zeolite used in the present invention.

As a method for producing Y-type zeolite supporting such metallic copper or a copper compound, an impregnation method using an ordinary metal salt aqueous solution, a vapor phase supporting method using sublimation of a copper compound, etc. can be considered, but the impregnation method is preferable.

The molar ratio of benzene and/or bromobenzene to Br2 and/or HBr in the present invention is 0.01 to 5.
0, preferably 0.1 to 10, more preferably 0.5
It is in the range of ~5.

The molar ratio of O, Br, and/or HBr in the present invention is 0.5 to 5.0, preferably 0.8 to 3.0.

These raw material gases may be introduced as they are or may be diluted with an inert gas.

The reaction temperature in the present invention is 100 to 400C, preferably 150 to 300C.

The pressure in the present invention may be reduced pressure, normal pressure, or increased pressure, but is preferably in the range of 0.5 to 10 atm, more preferably 0.8 to 5 atm.

(Effects of the Invention) By the method of the present invention, para-dibromobenzene can be obtained with a high selectivity such that the ratio of ni-(carboxylate) in dibromobenzene is 80% or more. is very advantageous.

(Example) Example 1 Na-Y type zeolite (manufactured by Linde, trade name: 5
K-40) was immersed in a 20% by weight CuBr2 aqueous solution and then evaporated to dryness to prepare a Y-type zeolite supporting CuBr2. The amount of Cu supported on the obtained catalyst was 18 weight.

Using this catalyst, oxidative bromination reaction of bromobenzene with hydrogen bromide was carried out under the following conditions.

Bromobenzene/HBr/0□/N, molar ratio=2/1/1/4 Reaction temperature r20 CI C,
WHS V (bromobenzene standard) = 4. Oh
r”, pressure crab normal pressure.

The results 6 to 4 hours after the start of the reaction were: bromobenzene conversion rate = 45%, dibromobenzene J selectivity = 95%, )! /bromobenzene selectivity = 3 excellent, ratio of para isomer in dibromobenzene = 88%.

Example 2 Using the catalyst used in Example 1, oxidative bromination reaction of bromobenzene with bromine was carried out under the following conditions.

Bromobenzene/Brl/o,/'Nt=4
/j/2/4, reaction temperature 220C, WH8V
-2, Ohr″″11 pressure crab normal pressure.

The results 5 to 6 hours after the start of the reaction were: bromobenzene conversion -47%, dibromobenzene selectivity: 96%, tribromobenzene selectivity: 34, and the proportion of para-isomer in dibromobenzene -90. Ta.

Example 3 NaY-type zeolite was immersed in a 50 IIl % CuBr aqueous solution and then evaporated to dryness to prepare Y-type zeolite supporting CuBr1. The amount of Cu supported was 23% by weight.

Using this catalyst, oxidative bromination reaction of benzene with hydrogen bromide was carried out under the following conditions.

Benzene/HBr/OH/Nx = 1/1
/ 178, reaction temperature 190C% WH8V (benzene standard) = 2, Ohr-', pressure crab normal pressure.

The results for 3 to 4 hours after the start of the reaction are the benzene conversion rate,...
609%, brominated benzene selectivity = 99%, and the distribution of products in brominated benzene is as shown in Table 1.

Table 1 Example 4 Using the catalyst used in Example 3, the oxidative bromination reaction of a mixture of benzene and bromobenzene with hydrogen bromide was carried out.
The test was conducted under the following conditions.

Benzene/Brombenzene/HBr/Os/
Nt=1/5/1.8/1.8/6
．． 8. Reaction temperature 200C.

WHS V (benzene/bromobenzene group S) =
2, Ohr-1, pressure crab normal pressure.

2-3 hours after the start of the reaction, 50-51 hours, 100-10
Table 2 shows the composition of the organic phase of the solution produced for 1 hour.

Table 2 Example 5 Y-type zeolite was immersed in a copper nitrate aqueous solution of 20%, evaporated to dryness, and further calcined in air at 400C for 4 hours to prepare Y-type zeolite supporting Cu0. This catalyst was further reduced at 450 C for 4 hours in a hydrogen stream to obtain a Y-type zeolite supporting metallic copper. The amount of metal copper supported was 11.

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

Bromobenzene/HBr 10t/N, = 4/
1/1/4, reaction temperature 2207::%WH8V=2.
Ohr'.

Pressure crab normal pressure.

The results at 3 to 4 hours after the start of the reaction were as follows: bromobenzene conversion rate = 20%, dibromobenzene selectivity = 95%, tribromobenzene selectivity = 3, 1 in dibromobenzene.
, the ratio of 4 units = 88 regrets.

Claims (3)

[Claims] (1) When producing paradibromobenzene by oxidatively brominating benzene, bromobenzene, or both in the gas phase using bromine, hydrogen bromide, or both, and oxygen, a metal is used as a catalyst. A method for producing paradibromobenzene, characterized by using Y-type zeolite supporting copper and/or a copper compound. (2) The method according to claim 1, characterized in that the amount of metallic copper and/or copper compound supported is 5% by weight or more based on the Y-type zeolite of the carrier. (3) The molar ratio of oxygen to bromine and/or hydrogen bromide is 0
．． 5 to 5.0.