JP2807064B2 - Manufacturing method of dinitrile - Google Patents

Description

The present invention relates to the oxidation of an aromatic diamine having two primary amino groups on an aromatic ring in the presence of a catalyst comprising a tertiary amine and a cuprous salt. In this reaction, an inert solvent in which the complex catalyst is insoluble is added, followed by separation of the tertiary amine in which the complex catalyst is soluble by distillation, and recovery and reuse of the precipitated complex catalyst.

Dinitrile is useful as a pharmaceutical raw material, an industrial raw material, particularly a polymer raw material.

[Problems to be solved by the prior art and the invention]

Conventionally, mucononitrile and its derivatives have been produced by halogenating 1,4-dicyano-2-butene followed by dehydrohalogenation (U.S. Pat. No. 2,564,102), or by decomposition of aromatic diazide [J. Am .chem.Soc.87
(5), 1147-8 (1965)], a method for aminating and oxidizing benzene with ammonia in the presence of a catalyst (U.S. Pat.
No. 559), a method of coupling acrylonitrile in the presence of a catalyst [J. Orga-nomet. Chem. 1978, 152 (2), 193].
-5], and a method of producing an aromatic o-diamine by oxidation of lead tetraacetate or oxidation of nickel peroxide is known.

However, the oxidation of aromatic o-diamine with lead tetraacetate or nickel peroxide requires a stoichiometric amount of catalyst. Moreover, these methods have a yield of about 60% and are not industrially preferable.

On the other hand, as a method for quantitatively producing mucononitrile from an aromatic o-diamine, a catalytic production method of oxidatively opening a ring in the presence of a catalyst containing a tertiary amine and a cuprous salt (Japanese Patent Publication No. No.-5133). According to the publication, after completion of the reaction, most of the excess tertiary amine as a solvent was distilled off from the reaction system, and then the residue containing the catalyst and mucononitrile was treated with ether to extract mucononitrile in the ether layer. There is a description of a method for quantitatively obtaining the target product, mucononitrile.

The present inventors have performed additional tests of the reaction method disclosed in the publication, and although mucononitrile can be obtained in high yield, the catalyst remaining as a residue in ether extraction becomes tar-like and adheres to the flask wall, and the catalyst is recovered as it is. It was found that this method was difficult to reuse, and in terms of cost and operability of the reaction, this method was hardly an industrial production method.

[Means for solving the problem]

In view of such circumstances, the present inventors have intensively studied an industrial production method of dinitrile, and as a result, have found a catalyst recovery method which is remarkably effective by adding an inert solvent and separating excess tertiary amine. It was completed.

That is, the present invention uses an aromatic diamine having two primary amino groups adjacent to an aromatic nucleus with a tertiary amine as a solvent,
In the method for producing dinitrile by oxidizing with molecular oxygen in the presence of a complex catalyst comprising the amine, cuprous salt and oxygen, the complex catalyst is not substantially dissolved in the reaction system,
In addition, an inert solvent having a boiling point higher than that of the tertiary amine to be used is added, and after completion of the reaction, excess tertiary amine is recovered by distillation, and the complex catalyst precipitated in the distillation residue is recovered by filtration. A method for producing dinitrile, comprising separating dienitrile from a filtrate, and a method for producing dinitrile, wherein the recovered catalyst is used repeatedly.

The reaction of the present invention can be represented, for example, as follows when using o-phenylenediamine as a starting material.

In the above reaction, the catalyst consisting of the tertiary amine and cuprous salt is oxidized by oxygen to form an active cupric tertiary amine oxygen complex, which is thought to oxidize the diamine to produce nitrile. Can be

The complex used in the reaction continues to blow oxygen to form an active cupric tertiary amine oxygen complex again,
Works catalytically. However, since the complex is soluble in a tertiary amine which is a reaction solvent, it is difficult to recover the complex as it is.

An object of the method of the present invention is to provide an industrial process for producing dinitrile by recovering the complex in the form of crystals after the reaction and reusing the complex.

Examples of the tertiary amine used in the method of the present invention include trimethylamine, triethylamine, tripropylamine, tributylamine, triallylamine, pyridine, 2-picoline, 3-picoline, quinoline, isoquinoline, morpholine, piperazine and the like. . Preferably, pyridine is used. These may be used alone or in combination of two or more.

Examples of the cuprous salt used in the method of the present invention include cuprous chloride, cuprous bromide, cuprous iodide, cuprous sulfate and the like.

Although the ratio of the tertiary amine to the cuprous salt, which is the composition of the catalyst of the present invention, is not particularly limited, one or more tertiary amine molecules are usually used per copper atom.

The aromatic diamine compound as a starting material of the method of the present invention may be any one in which a primary amine is bonded to an adjacent position on an aromatic nucleus, and a substituent is bonded to another position of the aromatic nucleus. No problem.

As the aromatic diamine compound preferably used in the reaction of the present invention, o-phenylenediamine, o-toluenediamine, 3,4-dimethyl-o-phenylenediamine,
-Chloro-o-phenylenediamine, 1,2-diaminonaphthalene and the like, but are not limited thereto.

 The method of the present invention will be described below based on embodiments.

A cuprous salt is added to the above-mentioned tertiary amines, and oxygen is blown into this solution to form a complex composed of the tertiary amine, cuprous salt and oxygen. Next, the aromatic diamine compound is dissolved in a tertiary amine or an inert solvent and slowly dropped into the complex solution.

When the aromatic diamine compound solution is dropped into the complex solution, oxygen is continuously blown into the complex solution, and the dropping rate of the aromatic diamine compound is adjusted so that the color of the complex remains green. After completion of the dropwise addition, an inert solvent in which the complex is insoluble is added to the reaction solution. Here, the inert solvent may be added before, after, or after the reaction or by dissolving the aromatic diamine compound added dropwise during the reaction.

Reaction temperatures range from 10 to 80 ° C, preferably 20 to 40 ° C. Oxygen blowing rate is 0.1 per mole of aromatic diamine.
It is 1 to 10 / min, preferably 0.5 to 2 / min.

The inert solvent to be added may be any solvent as long as it is inert to the complex and the reaction of the present invention and has substantially no solubility in the complex. Specific examples include aliphatic hydrocarbons such as hexane, cyclohexane, heptane, octane, nonane, and decane; and aromatic hydrocarbons such as benzene, toluene, xylene, trimethylbenzene, monochlorobenzene, dichlorobenzene, and tetralin.

The amount of the inert solvent to be added is 0.5 to 10 ml / mmole, preferably 1 to 3 ml / mmole with respect to the starting aromatic diamine.
It is.

Since the tertiary amine is distilled off from the mixed solution containing the tertiary amine by distillation, the inert solvent used in the method of the present invention has a boiling point of 10 ° C. or higher than that of the tertiary amine, preferably 20 ° C.
It is necessary to select one higher than ℃.

Next, excess tertiary amine is distilled off from the reaction mixture by distillation, and the distillation residue is cooled, whereby a complex comprising a cuprous salt and a tertiary amine is precipitated as crystals. The precipitated complex is separated by a usual solid-liquid separation method.

As a specific method, vacuum filtration is often used. The separated and recovered complex can be used for the subsequent reaction.
The second and subsequent times had the same catalytic activity as the first time. The filtrate is subjected to a purification method such as distillation under reduced pressure, distillation or recrystallization after distilling off the inert solvent to obtain the desired dinitrile.

〔The invention's effect〕

According to the method of the present invention, the catalyst can be easily recovered, and the recovered catalyst can be used repeatedly for the reaction.
Dinitriles can be produced very advantageously on a high industrial scale.

〔Example〕

Example 1 3.96 g of cuprous chloride was added to 100 ml of pyridine, and oxygen was added to 100 m
Stir while blowing at l / min. Initially, the yellow solution turns dark green as oxygen is bubbled in to form the complex. After injecting oxygen for 1 hour, a solution in which 12.22 g of 3,4-diaminotoluene was dissolved in pyridine was added dropwise while continuing to inject oxygen at 100 ml / min so that the reaction solution remained dark green. After completion of the dropwise addition, 200 ml of xylene was added to the reaction solution, pyridine was distilled off, and the precipitated complex was filtered under reduced pressure. The complex was washed with n-hexane and then dried under reduced pressure to obtain 6.72 g of a recovered complex. The filtrate is 6
The mixture was washed with N hydrochloric acid, neutralized with a saturated aqueous solution of sodium hydrogen carbonate and then separated.
10.87 g of cis-mucononitrile (purity 98.0%, yield 90.2%)
%). Melting point 52-54 ° C (literature value 53-54 ° C) The recovery of pyridine by the above operation was 98.3%.

6.72 g of the complex recovered in the above operation was used in place of the cuprous chloride described above, and the same operation was further performed twice. The second time was 10.66 g of 2-methyl-cis, cis-mucononitrile ( Purity 97.8%, yield 88.3%) and recovered complex 6.58g
The third time, 9.77 g of 2-methyl-cis, cis-mucononitrile (purity 97.8%, yield 79.5%) and 5.92 g of recovered complex.
Obtained.

Example 2 The reaction was repeated three times in the same manner as in Example 1 except that o-dichlorobenzene was used in place of xylene of Example 1. The first time was the reaction of 2-methyl-cis, cis-mucononitrile with 1
0.36 g (purity 98.2%, yield 86.1%) and 6.89 g of the recovered complex were obtained. The second time is 2-methyl-cis, cis-mucononitrile with 1
0.28 g (purity 98.0%, rate 85.3%) and 6.53 g of recovered complex were obtained. Third time, 2-methyl-cis, cis-mucononitrile was added to 1
0.03 g (purity 97.2%, yield 82.5%) and 6.52 g of a recovered complex were obtained.

Example 3 The reaction was repeated three times in the same manner as in Example 1 except that 1,2,4-trimethylbenzene was used in place of xylene of Example 1. As a result, the first reaction was performed using 10.56 g of 2-methyl-cis, cis-mucononitrile. g (purity 96.0%, yield 85.8%) and recovered complex 6.72
g was obtained. The second time was 10.32 g of 2-methyl-cis, cis-mucononitrile (purity 97.2%, yield 84.9%) and the recovered complex was 6.
23 g were obtained. The third time was 10.10 g of 2-methyl-cis, cis-mucononitrile (purity 95.2%, yield 81.4%) and the recovered complex was 5.
98g was obtained.

Comparative Example 1 The reaction was carried out in the same manner as in Example 1. After the dropwise addition of the pyridine solution of 3,4-toluenediamine, about 90% of pyridine was distilled off from the reaction solution by distillation. Next, ether 200m to the residue
After l was added to extract mucononitrile, the ether extract was dried and concentrated to obtain 11.24 g (purity: 92.5%, yield: 88%) of 2-methyl-cis, cis-mucononitrile.

At the time of ether extraction, the complex remaining as an insoluble substance adhered to the flask wall or the like, and it was difficult to recover the complex as it was. In addition, the amount of pyridine distilled off by distillation is about 90% (if it is further distilled, the reaction product adheres to the flask wall and it is difficult to extract). Since the pyridine remains, the complex partially dissolves in the ether layer. Oops.

Continuation of front page (58) Field surveyed (Int.Cl. ⁶ , DB name) C07C 255/09 C07C 253/00

Claims (2)

(57) [Claims] 1. An aromatic diamine having two primary amino groups adjacent to an aromatic nucleus in the presence of a tertiary amine as a solvent in the presence of a complex catalyst comprising said amine, cuprous salt and oxygen. In the method of producing dinitrile by oxidizing with molecular oxygen, the complex catalyst is not substantially dissolved in the reaction system, and an inert solvent having a higher boiling point than the tertiary amine used is added, After the reaction is completed, an excess tertiary amine is recovered by distillation, the complex catalyst precipitated in the distillation residue is recovered by filtration, and then dinitrile is separated from the filtrate. 2. A method for producing dinitrile, wherein the catalyst recovered by the method according to claim 1 is used repeatedly.