JP3443326B2 - Method for producing N-substituted maleimides - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing N-substituted maleimides, and more specifically, to prevent solids from adhering to the inner surfaces of condensers and pipes, and to stabilize N-substituted maleimides for a long period of time. It relates to a method of manufacturing.

[0002]

2. Description of the Related Art A process for producing N-substituted maleimides from maleic anhydride and a primary amine in one step in the presence of an acid catalyst in an inert organic solvent, and maleic anhydride and a primary amine to give maleic acid. The method for producing N-substituted maleimides by dehydration ring closure reaction of this maleamic acid is known well. This reaction is carried out while removing the produced water by azeotropic distillation with an inert organic solvent, but at this time, the inner surface of the condenser contacting with the steam or the inner surface of the pipe connecting the reactor and the condenser. Solid matter may adhere to the tube and, in extreme cases, may cause tube blockage. The adhesion of the solid matter is caused by a compound which is insoluble in an inert organic solvent such as maleic acid, fumaric acid, N-substituted maleamic acid, or N-substituted fumaramic acid, which is produced during the reaction, and which is anhydrous in the gas phase. It is believed that the maleamic acid formed by the reaction of maleic acid with the vapor of primary amines will also attach.

As a method for preventing the above-mentioned tube clogging, for example, in JP-A-4-139166, when maleic anhydride and a primary amine are continuously added and reacted,
A method of coexisting a specific stabilizer of a copper compound and / or a phosphorus compound to suppress the production of fumaric acid and N-substituted monofumaramic acid and to prevent clogging of a condenser and a pipe is described.

Further, Japanese Patent Laid-Open No. 10-59935 discloses a method of adding a protic polar solvent such as formic acid, acetic acid and propionic acid into the reaction system to prevent clogging of condensers and pipes and side reactions. Have been described.

[0005]

DISCLOSURE OF THE INVENTION The present invention relates to the production of N-substituted maleimides from maleamic acid or maleic anhydride and a primary amine in an inert organic solvent.
It is an object of the present invention to provide a method for simply and effectively preventing solid substances from adhering to the inner surfaces of a condenser and a pipe by using a completely different means from the above-mentioned conventional method.

[0006]

According to the research conducted by the present inventors, it was found that the above object can be achieved by directly introducing maleic amic acid or at least one of maleic anhydride and primary amine into a reaction solution. .

That is, the present invention uses a device comprising a reactor, a condenser, and a pipe connecting the reactor and the condenser, and uses maleic acid or maleic anhydride and a maleic anhydride in an inert organic solvent. In the method for producing N-substituted maleimides from amines, maleic amic acid as a raw material, or maleic anhydride and at least one of primary amines are directly introduced into a reaction solution. It is a manufacturing method.

Further, in the above-mentioned method , the present invention relates to the inner surface of the condenser and the inner surface of the pipe, and at least a part of the entire inner surface thereof has (A) a surface roughness of 6.3 S or less. And / or (B) a method for producing N-substituted maleimides wet with an inert organic solvent. Well
The present invention also provides the method described above, further comprising:
As for the inner surface that contacts the gas phase,
(A) Surface roughness 6.3S or less smoothness
And / or (B) wet with an inert organic solvent
It is a method for producing N-substituted maleimides.

In the present invention, "(A) Surface roughness 6.3"
"Smoothness of S or less and / or (B) wetting with an inert organic solvent" includes the following aspects, for example, when this treatment is performed on the entire inner surface.

(A) The entire inner surface has a surface roughness of 6.3 S or less.

(B) Wetting the entire inner surface with an inert organic solvent.

(C) The entire inner surface is made smooth with a surface roughness of 6.3 S or less, and a part of it is wet with an inert organic solvent.

(D) The entire inner surface is wetted with an inert organic solvent, and a part thereof has a surface roughness of 6.3 S or less.

(E) A part of the entire inner surface has a surface roughness of 6.3.
The degree of smoothness is S or less, and the rest is wet with an inert organic solvent.

(F) The entire inner surface has a surface roughness of 6.3 S or less and is wet with an inert organic solvent.

The above-mentioned treatment in the present invention does not necessarily have to be carried out on all the inner surfaces of the condenser and the inner surface of the pipe, and unless the solid matter adheres to an undesired degree, the whole inner surface thereof is not required. You may go to a part of. Among them, the above (a) to
It is preferable to perform any of (f).

The "wet with an inert organic solvent" of the present invention is also used.
Means, for example, to form a liquid film of an inert organic solvent to the extent that the contact between the inner surface of the pipe and the vapor from the reactor can be sufficiently prevented, and as one of its concrete means, a spray nozzle. Can be used to spray an inert organic solvent onto the inner surface.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, N-substituted maleimides are produced in one step from maleic anhydride and primary amine as raw materials in the presence of an acid catalyst in an inert organic solvent. And a method for producing N-substituted maleimides from a maleamic acid produced from maleic anhydride and a primary amine using this maleic acid as a raw material. The present invention does not have a characteristic in the reaction itself, and can produce a corresponding N-substituted maleimide from maleic acid or maleic anhydride and a primary amine under conventionally known reaction conditions. .

Typical examples of primary amines used as raw materials are methylamine, ethylamine, n-propylamine, isopropylamine, n-butylamine, sec-
Butylamine, tert-butylamine, n-hexylamine, n-dodecylamine, allylamine, benzylamine, cyclohexylamine, aniline, nitroaniline, aminophenol, aminobenzoic acid, anisidine, ethoxyphenylamine, monochloroaniline, dichloroaniline, toluidine. , Xylidine, ethylaniline and the like.

The maleamic acid is obtained by reacting the above-mentioned primary amine with maleic anhydride,
As a typical example thereof, N-phenylmaleamic acid,
Examples thereof include N-benzylmaleamic acid, N-cyclohexylmaleamic acid and N-tribromophenylmaleamic acid.

Typical examples of the acid catalyst include inorganic or organic monobasic acids and polybasic acids such as sulfuric acid, paratoluenesulfonic acid, orthophosphoric acid, metaphosphoric acid, pyrophosphoric acid, benzenesulfonic acid, methanesulfonic acid and trichloroacetic acid. Amine salts obtained by neutralizing these basic acids with amines, which are the raw materials for the production of maleimides; acidic ion exchange resins and the like.

Typical examples of the inert organic solvent are benzene, toluene, petroleum fraction having a boiling point of 50 to 120 ° C., xylenes, ethylbenzene, isopropylbenzene, cumene, mesitylene, tert-butylbenzene, pseudocumene, trimethylhexane, octane. , Tetrachloroethane, nonane, chlorobenzene, ethylcyclohexane, petroleum fraction having a boiling point of 120 to 170 ° C., m-dichlorobenzene, sec-butylbenzene, p-dichlorobenzene, decane, p-cymene, o-dichloro Examples thereof include benzene, butylbenzene, decahydronaphthalene, tetrahydronaphthalene, dodecane, naphthalene, cyclohexylbenzene, and a petroleum fraction having a boiling point of 170 to 250 ° C.

Various reaction conditions such as the ratio of maleic anhydride and primary amine, the amount of the acid catalyst used, the amount of the inert organic solvent used and the reaction temperature can be appropriately selected from the known condition range.

FIG. 1 is an explanatory view showing one embodiment of the present invention, and FIG. 2 is an explanatory view showing another embodiment. As shown in FIGS. 1 and 2, in the method of the present invention, the reactor (jacketed reaction vessel 4), the vapor from the reactor (the azeotrope of the produced water and the inert organic solvent) is condensed. Of the condenser (cooling condenser 6) and a pipe (steam conduit 5) connecting the reactor and the condenser. Hereinafter, the present invention will be described in detail with reference to FIGS. 1 and 2.

(1) The raw material maleamic acid or at least one of maleic anhydride and primary amine is directly introduced into the reaction solution.

Specifically, as shown in FIGS. 1 and 2, the raw material may be supplied from a pipe having an opening in the reaction solution, such as a maleic anhydride supply pipe 1 and a primary amine supply pipe 2. . Either one of maleic anhydride and primary amine may be directly introduced into the reaction solution, but it is preferable to introduce both of them into the reaction solution directly. The position of the opening in the reaction solution is not particularly limited, and the optimum position may be appropriately determined.

In the embodiment shown in FIG. 1, maleic anhydride and a primary amine are directly introduced into a reaction solution from a maleic anhydride supply pipe 1 and a primary amine supply pipe 2, respectively, and produced by a dehydration ring closure reaction. Water is withdrawn as an azeotrope with an inert organic solvent and this vapor is introduced into the cooling condenser 6 via the vapor conduit 5 and condensed. The condensate is separated into an oil phase and an aqueous phase in the water separation tank 7, and the inert organic solvent in the oil phase is circulated to the jacketed reaction tank 4.

(2) In the above (1), with respect to the inner surface of the condenser and the inner surface of the pipe, at least a part of all the inner surfaces thereof has (A) a surface roughness of 6.3 S or less, And / or (B) Wetting with an inert organic solvent.

In the embodiment shown in FIG. 2, part of the inert organic solvent from the water separator 7 is circulated in the reaction tank 4, and the remaining inert organic solvent is introduced from the shower nozzle 15 into the vapor conduit 5. , The inner surface of the pipe is wetted or introduced into the cooling condenser 6 and the steam conduit 5 from the shower nozzles 14 and 15, respectively, and the inner surface of the pipe and the inner surface of the condenser are treated with an inert organic solvent. Get wet. For the wetting with the inert organic solvent, as long as direct contact between the inner surface of the condenser and the inner surface of the pipe and vapor can be prevented, other than spraying the inert organic solvent using the shower nozzle described above. The method can also be appropriately adopted. In addition,
As the shower nozzle, for example, a circular entire surface water spray type nozzle (EX4 type, NIIKURA CORPORATIO
N) and the like can be used. As the inert organic solvent, a new inert organic solvent may be used, but it is preferable to recover and circulate the inert organic solvent used for the cyclization dehydration reaction before use.

In the embodiment shown in FIG. 2, the inner surface of the pipe and / or the inner surface of the condenser may have a smoothness with a surface roughness of 6.3 S or less. The surface roughness and S referred to in the present invention are defined by JIS B0601-1982-3.4. In particular, it is preferable that the surface roughness is 1.6S or less.

The polishing means for achieving the above smoothness is not particularly limited, and a mechanical polishing method, an electrolytic polishing method or the like can be used. For example, # 200 or more, preferably # 3
A buffing of 00 or more, more preferably # 400 or more may be performed.

In order to perform the above treatment on the inner surface of the condenser, it may be performed on the entire inner surface of the condenser, or at least only on the inner surface in contact with the steam from the pipe. The same applies to wetting with an inert organic solvent.

Further, in the present invention, at least a part of the inner surface of the condenser and the inner surface of the pipe which come into contact with the gas phase portion in the reactor are (A) surface roughness 6.3S or less. And / or (B) wet with an inert organic solvent.

[0034]

EFFECTS OF THE INVENTION According to the method of the present invention, since solid substances can be easily and effectively prevented from adhering to the inside of the condenser and the pipe, N-substituted maleimides can be stably produced over a long period of time.

[0035]

EXAMPLES The present invention will be described in more detail below with reference to examples. In addition, the shower nozzle used here is a circular whole surface water spray type nozzle (EX470 type, NIIKURA).
(Corporation).

Example 1 200 kg of ortho-xylene and 40 k of orthophosphoric acid (85%) were placed in a preparation tank of 500 liter capacity equipped with a stirrer.
After supplying g, diatomaceous earth (trade name: Radiolight #
200, 60 kg of Showa Kagaku Kogyo Co., Ltd. was added to support orthophosphoric acid on diatomaceous earth. Then, by adding 19 kg of aniline, a catalyst was prepared in which a part of the supported acid was used as an amine salt.

Thermometer 13, steam conduit (inner diameter 105 mm)
5, a cooling condenser 6, a water separation tank 7 and a stirrer 3 were arranged as shown in FIG. 1, and 600 kg of ortho-xylene, 0.05 kg of copper dibutyldithiocarbamate and the above-mentioned material were added to a jacketed reaction tank 4 having a volume of 2 m ^3. The supported catalyst of was charged and heated and stirred so that the internal temperature became 130 ° C. Next, 110 kg of maleic anhydride and 100 k of aniline
g from each of the maleic anhydride supply pipe 1 and the aniline supply pipe 2 opened at a depth of 300 mm from the liquid surface over 1 hour to quantitatively add and carry out the reaction. After completion of the dropping, the reaction is further continued for 3 hours. By doing so, N-phenylmaleimide was produced. The water produced along with the progress of this reaction is distilled off together with orthoxylene, and the water separation tank 7
The ortho-xylene was refluxed to the reaction tank 4 while removing water out of the system in. After the completion of the reaction, the steam conduit 5 and the cooling condenser 6 were disassembled, and the solid matter adhering to the inner surface was recovered, dried and weighed, and it was 60 g.

Comparative Example 1 N was carried out in the same manner as in Example 1 except that the reaction was carried out while supplying both maleic anhydride and aniline from the supply pipes open to the gas phase part of the reaction tank 4. -Phenylmaleimide was prepared. After the completion of the reaction, the steam conduit 5 and the cooling condenser 6 were disassembled, and the solid matter adhering to the inner surface was collected, dried and weighed to find that it was 870 g.

From the comparison between Example 1 and Comparative Example 1, it is possible to effectively prevent solid substances from adhering to the inner surfaces of the condenser and the pipe when the raw materials maleic anhydride and aniline are directly introduced into the reaction solution. I understand.

[0040]

[0041]

[0042]

[0043]

[0044]

[0045]

[0046]

[0047]

[0048]

Example 2 An ortho mixer was placed in a preparation tank having a capacity of 500 liter equipped with a stirrer.
Siren 200kg and orthophosphoric acid (85%) 30k
After supplying g, granular silica gel (trade name: Microbi
Silica silica MB-4B, manufactured by Fuji Silysia Chemical Ltd. 1
Add 00 kg to support orthophosphoric acid on silica gel.
Let Then, loading by adding 8 kg of aniline
A catalyst was prepared in which a part of the obtained acid was used as an amine salt. temperature
Total 13, steam conduit (inner diameter 105 mm) 5, cooling condenser
6, water separation tank 7, shower nozzles 14, 15 and agitator
Using a device in which the stirrer 3 is arranged as shown in FIG.
jacketed reaction vessel 4 m ^3, ortho-xylene 600
kg, copper dibutylthiocarbamate 0.02 kg and
Charge the above-mentioned supported catalyst and heat it so that the internal temperature is 130 ° C.
Heated and stirred. Next, 110 kg of maleic anhydride and
Maleic anhydride supply pipe in which 100 kg of aniline was opened to a depth of 300 mm from the liquid surface in the reaction tank 4, respectively.
And quantitatively added from the aniline supply pipe over 1 hour
While conducting the reaction, after the dropping is completed, the reaction is continued for another 3 hours.
To produce N-phenylmaleimide. reaction
Water produced by the progress of
While removing the water in the water separation tank 7 to the outside of the system,
Xylene was refluxed to the reaction tank 4. In addition, the steam conduit 5
And all internal surfaces of the cooling condenser 6 are manufactured by Tosa Emery Co., Ltd.
The surface roughness is 1.
The smoothness was 6S. Above the steam conduit 5 and cooling condenser 6
In the reaction tank 4 at the contact portion with the gas phase portion
Part of the siren through the attached shower nozzles 14 and 15
Was sprayed, and the reaction was carried out while maintaining the wet state of the wall surface.
The shower flow rate at this time is the steam conduit 5 and the cooling condenser 6.
Each of the tops was sprayed at 300 liters / hour. After the completion of the reaction, when the steam conduit 5 and the cooling condenser 6 were disassembled, no solid matter adhered to the inner surface.

From these results, the raw materials maleic anhydride and aniline were directly introduced into the reaction solution, and the solvent orthoxylene was sprayed onto the inner surfaces of the condenser and piping to wet the surface, and then the condenser and It can be seen that when the inner surface of the pipe has a surface roughness of 1.6 S or less, adhesion of solid matter to the inner surfaces of the condenser and the pipe can be very effectively prevented.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing another embodiment. 1 Maleic anhydride supply pipe 2 Primary amine supply piping 3 stirrer 4 jacketed reaction tank 5 steam conduit 6 Cooling condenser 7 water separation tank 8 reflux liquid circulation pump 9 Steam entrance 10 steam exit 11 Cooling water inlet 12 Cooling water outlet 13 Thermometer 14, 15 Shower nozzle

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Taiji Kinoshita 1 992 Nishikioki, Kamahama-ku, Himeji-shi, Hyogo Prefecture Nihon Shatai Co., Ltd. (58) Fields investigated (Int.Cl. ⁷ , DB name) C07D 207 / 448 CA (STN) REGISTRY (STN)

Claims (4)

(57) [Claims] 1. A system comprising a reactor, a condenser, and a pipe connecting the reactor and the condenser is used, and maleic acid or maleic anhydride and a primary amine are converted to N in an inert organic solvent. In the method for producing a substituted maleimide, a method for producing an N-substituted maleimide, characterized in that maleic acid as a raw material or at least one of maleic anhydride and a primary amine is directly introduced into a reaction solution. 2. With respect to the inner surface of the condenser and the inner surface of the pipe, at least a part of the entire inner surface thereof has (A) a surface roughness of 6.3 S or less, and / or (B) is not smooth. The N- according to claim 1, which is wet with an active organic solvent.
A method for producing a substituted maleimide. 3. Further, with respect to the inner surface in contact with the gas phase portion in the reactor, at least a part of the whole inner surface is
(A) A surface roughness of 6.3 S or less, and /
Or (B) according to claim 1 or moistened with an inert organic solvent
2. The method for producing N-substituted maleimides according to 2 . 4. An inert organic solvent is introduced from a shower nozzle.
The N-substituted male according to claim 2 or 3, wherein the N-substituted male is moistened by entering.
Method for producing imides.