JPS61171455A - Method for aminating 1,4-dibromobenzene - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention provides a method for aminating 1,4-dibromobenzene,
1, which is an intermediate raw material for synthetic fibers, dyes, antioxidants, etc.
The present invention relates to a method for synthesizing 4-diaminobenzene and/or 4-bromoaniline, which is an intermediate raw material for dyes, synthetic fibers, etc.

(Prior art) There is no known amination technology for 1.4-dibromobenzene.As a related reaction, a method for producing diaminobenzene by aminating dichlorobenzene is known (dichlorobenzene method) (Unexamined Japanese Patent Publication No. (Sho 51-59824, JP 53-77023, JP 56-16449).

Another synthetic route for 1.4-diaminobenzene is a method starting from aniline and passing through diazobenzene nitrate, etc. (aminoazobenzene method) (JP-A-52-65
No. 230, JP-A-55-94349, JP-A-57-1
22047), a method starting from 1,4-benzenedicarboxylic acid and utilizing the Hofmann decomposition reaction (Hoffmann decomposition method) (JP-A-49-13125, etc.), starting from acetanilide and passing through 4-nitroaniline. Nitroaniline method [edited by Kirk Othmer, Encyclopedia of Chemical Industry (Ki)
rk-Othmerliil, t! ncyclop
edia of chemical technology
ology).

3rd edition, Vol. 2, pp. 313, 365], Aminophenol process starting from nitrobenzene via 4-aminophenol [edited by Kirk Othmer, Encyclopedia of the Chemical Industry (
Kirk-Othmer [, Encyclopedia
ofChe+m1cal Technology),
3rd edition, 2 volumes, 371 pages and JP-A-1537-1537
51], the hydroquinone method synthesized by amination of hydroquinone (Japanese Patent Application Laid-open No. 49-29176), the direct amination method synthesized from aniline and ammonia (US Pat. No. 3,919,155) via 4-iodoaniline A method is known (US Pat. No. 3,975,349).

A method for producing halogenated aniline includes ammonolysis of halogenobenzene with an ammonia aqueous solution using an 8-hydroxyquinoline derivative as a complexing agent (Japanese Unexamined Patent Publication No. 59-1375O).
Method by reduction of 4-nitrobenzene (JP-A-51-1
No. 22029) is known.

(Problems to be Solved by the Invention) The conventional techniques for producing 1,4-diaminobenzene and/or 4-bromoaniline each have serious problems.

1. Among the known synthesis methods for 4-diaminobenzene, the dichlorobenzene method requires high temperature and high pressure as reaction conditions, produces a large amount of tar-like high boiling point substances as a by-product, and is difficult to purify. difficult to convert. For example,
No. 263 teaches that at temperatures below 175° C., amination of dichlorobenzene with ammonia does not proceed much.

In addition, Japanese Patent Publication No. 56-40145 states that since the amination of aromatic cibarides (all examples are aromatic dichlorides) with ammonia hardly proceeds below 160°C, it should be carried out at 170 to 240°C; It is taught that 5 to 7% of heavy substances are produced as by-products based on the aromatic diamine that is the main product.

In these methods, the coexistence of water is essential, but on the other hand, the coexistence of water makes separation of the reaction product diamine extremely difficult. In order to separate the diamine, more than the stoichiometric amount of sodium hydroxide is added to the reactant, the copper compound of the catalyst is precipitated and separated, and the diamine salt produced is converted to free diamine, and then the diamine is extracted. Special Publication No. 55-33709).

Tsukuda et al. 0)) L/ -) (7) *717 (D production method 60 also has problems. Easy,
It is a danger. The Hofmann degradation method also involves long steps, and the purification of intermediates and products is complicated. In the nitroaniline method, the starting material acetanilide is expensive and the process is long.

The aminophenol method is an electrolytic method in which the synthesis of the intermediate 4-aminophenol is complicated and requires expensive equipment, and 4-aminophenol is unstable and difficult to handle.

The latter amination step not only requires high temperature and high pressure reaction conditions, but also produces a tar-like high-boiling substance as a by-product.

In the hydroquinone method, the raw material hydroquinone is expensive, and
Requires high temperature and high pressure reaction conditions. The direct amination method requires harsh conditions and has low yield and selectivity. The iodoaniline method uses an expensive and highly corrosive iodine compound, and also produces an isomer of 1,2-diaminobenzene as a by-product, making purification difficult.

JP-A-59-13 as a method for producing halogenated aniline
The method of No. 750 includes dichlorobenzene method, 1.4-
In addition to having the same problems as the method for producing diaminobenzene, the examples disclosed are 1.3.5-) A method for producing 3,5-dichloroaniline from dichlorobenzene and a method for producing aniline from monochlorobenzene. limited to law.

In addition, the method of JP-A-51-122029 uses 1 of the raw materials.
- There is no selective synthesis method for bromo-4-nitrobenzene (it is expensive).

(Means for Solving the Problems) As a result of intensive studies on a method for aminating 1,4-dibromobenzene, the present inventors discovered that 1,4-dibromobenzene and ammonia were combined in the coexistence of an acyclic saturated hydrocarbon. The present inventors have discovered that 1,4-dibromobenzene can be aminated by reacting it in the presence of one or more selected from , zinc compounds, and cadmium compounds, and have completed the present invention. That is, the present invention provides a method of aminating 1,4-dibromobenzene by reacting it with ammonia in the coexistence of an acyclic saturated hydrocarbon and one or more selected from zinc compounds and cadmium compounds.

In the method of the present invention, the acyclic saturated hydrocarbons include:
It may be a normal form, an iso form, or a mixture of a normal form and an iso form. Acyclic saturated hydrocarbons have 4 to 16 carbon atoms
is desirable. If the number of carbon atoms is 4 or more, the pressure will not be too high, and if the number of carbon atoms is 16 or less, the reaction will proceed easily. Examples of acyclic saturated hydrocarbons used in the method of the present invention include n-butane, i-butane, n-pentane, i-
Pentane, n-hexane, i-hexane, n-hebutane, i-hebutane, n-octane, i-octane, n-nonane, i-nonane, n-decane, i-decane, n-undecane, i- undecane, n-dodecane, i-dodecane, n-) lysocane, i-tridecane, n-tetradecane, i-tetradecane, n-pentadecane, i-pentadecane, n-hexadecane, i-hexadecane. The number of carbon atoms in the acyclic saturated hydrocarbon is more preferably 5 to 12. The amount of acyclic hydrocarbon is preferably 1 to 100 ml, and 3 to 30 ml per 1 g of 1,4-dibromobenzene.
1 is more preferred.

The zinc compounds as well as the cadmium compounds in the process of the invention have a catalytic effect in the process of the invention. Examples of the zinc compound and cadmium compound in the method of the present invention include halides such as bromide and chloride, oxides, hydroxides, organic acid salts such as succinic acid, ammine complexes of these compounds, or combinations thereof. . The amount of one or more selected from zinc compounds and cadmium compounds is o, ooi to 5 in terms of zinc atoms and/or cadmium atoms per 1 gram mole of 1,4-dibromobenzene.
Gram atoms are preferred, and 0.01 to 1 gram atoms are more preferred.

In the method of the present invention, the reaction temperature is preferably 70 to 160°C. A temperature of 70°C or higher is preferable because the reaction is fast;
C. or lower is preferable because the selectivity of the reaction is high.

85-140°C is more preferable.

In the method of the present invention, the reaction pressure is 10 to 250 kg/
aJG is preferred, 50-250kg/c! aG is more preferred.

(Effect of the invention) According to the method of the invention, 1,4-dibromoben
By aminating conjugate, 1,4-diaminobenzene can be produced, 4-bromoaniline can be produced, or 1,4-diaminobenzene and 4-bromoaniline can be co-produced. .

The rate of production of amphibiotic acids varies depending on the reaction conditions, particularly the reaction pressure and the type of acyclic saturated hydrocarbon.

In the process of the invention, one of the products, 1,4-diaminobenzene, has little or no solubility in the acyclic saturated hydrocarbons of the process, whereas 1,4-dibromobenzene is well melt. The solubility of the other product, 4-bromoaniline, is intermediate between the former two. Furthermore, 1,4-diaminobenzene precipitates as a free amine. Due to these effects, product separation is extremely simple in the method of the present invention. Furthermore, in the method of the present invention, there is almost no by-product of high-boiling substances such as tar (and the product can be purified very easily).

Due to these effects, the present invention provides an economical method for producing highly pure 1,4-diaminobenzene and/or 4-bromoaniline.

(Example) Example 1 5 g of 1,4-dibromobenzene, 3 g of zinc bromide, and 40 ml of n-nonane were placed in an autoclave with an internal volume of 200 ml equipped with a stirrer, and the autoclave was immersed in a dry ice/ethanol bath to remove ammonia. Introduced.

This autoclave was heated to 100℃ and the pressure cuff was 5kg/ajG.
The mixture was kept under stirring for 8 hours. Autoclave at room temperature
The pressure was returned to normal, and the reaction product was analyzed by gas chromatography.

1.5% of 4-dibromobenzene changed, changed 1
, 1,4 with a yield of 20 mol% based on 4-dibromobenzene
-diaminobenzene was obtained with a yield of 80 mol% 4-
Bromoaniline was obtained.

Example 2 1.4-dibromobenzene 5g, cadmium bromide 5g,
40 ml of n-pentane was charged into an autoclave, and after introducing ammonia, the autoclave was maintained at 110° C. and a pressure of 85 kg/cjG for 8 hours with stirring. ], 3 of 4-dibromobenzene
% changed, 5 per 1,4-dibromobenzene changed
1,4-diaminobenzene was obtained with a yield of 9
4-bromoaniline was obtained with a yield of 5 mol%.

Claims (2)

[Claims] (1) 1,4-dibromobenzene characterized by reacting 1,4-dibromobenzene and ammonia in the coexistence of one or more selected from acyclic saturated hydrocarbons, zinc compounds, and cadmium compounds. Amination method. (2) The method according to claim 1, wherein the acyclic saturated hydrocarbon has 4 to 16 carbon atoms.