JP2732799B2 - Method for transporting and storing solutions of maleimides in acrylonitrile - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for transporting or storing maleimides as a solution of acrylonitrile.

[0002] Maleimides are useful compounds as raw materials for resins, medicines, agricultural chemicals and the like, but the present invention provides a safe and simple method for transporting and storing maleimides.

[0003]

2. Description of the Related Art Conventionally, maleimides which are solid at ordinary temperature are generally handled in the form of powder, flakes, tablets and the like. However, the maleimides in such a form include a fine powder of the maleimides.

[0004] In particular, during the transfer of such solid maleimides, pulverization of the maleimide proceeds, and a large amount of fine powder of the maleimide is generated.

Maleimides themselves are irritating to the human body. In particular, inhalation of fine powder irritates the nasal cavity and throat, causing coughing and sneezing, and undesired properties such as inflammation when left on the skin. have.
Therefore, when handling maleimides containing such a fine powder, strict care must be taken to avoid contact with the skin as much as possible.

Therefore, a great deal of labor is required to minimize the generation of fine powder when transferring maleimides and to remove the fine powder from maleimides after transfer.

In addition, the transfer of solid materials often involves
A solid substance is filled into a paper bag, a drum, a container or the like and transported. However, in these cases, contact between the maleimide and the human body cannot be avoided, and it is inevitable that the maleimide fine powder adheres to the human body.

[0008] In addition, the transfer of solid substances by pipes so as not to come into contact with the human body is basically difficult. In order to stably transfer these solid substances, for example, the inside of the pipes is blocked during the transfer of pipes. Strict restrictions are imposed on the shape, size, specific gravity, etc. of the solid.

As described above, it must be said that the method of transferring maleimides which are solid at ordinary temperature has a number of difficult problems. The same is true for the storage method.

On the other hand, a method of transporting or storing maleimides as a solution of acrylonitrile is disclosed in JP-A-62-1.
No. 26167. This method can be said to be an excellent method in that the above problems can be solved when dealing with maleimides.

Usually, an acrylonitrile solution of a maleimide is transported using a tank truck, a bulk container, a tank wagon, a tanker, or the like.

However, transporting maleimides in the form of such an acrylonitrile solution is not economical because the transporting effect of the maleimides is poor, in other words, the transportation cost per unit weight of the maleimides is high. was there.

Therefore, it is conceivable to transport in the form of a highly concentrated acrylonitrile solution in order to make the transportation cost as low as possible. However, by increasing the concentration of the maleimides in the acrylonitrile solution, the maleimides can be easily converted from the acrylonitrile solution. It is also pointed out that the solution is precipitated out of the solution and the whole solution is slurried or solidified, and therefore, handling becomes difficult in transportation or storage.

Further, in order to prevent such maleimides from being precipitated, it is necessary to keep a tank or a transportation pipe or a valve for transporting or storing the acrylonitrile solution at a high temperature, which is very complicated. In addition, it causes a great economical problem that expensive heat insulation equipment is required.

[0015] Such a problem is particularly serious and fatal for transportation with an acrylonitrile solution in winter or in cold regions. In addition, considering that acrylonitrile has a low boiling point of 77.3 ° C. (760 mmHg) and that it is highly toxic and extremely flammable, maintaining an acrylonitrile solution at a high temperature poses a safety problem. I can't help but.

[0016]

As described above, the conventional method of dissolving maleimides in acrylonitrile and transporting or storing the same is not a completed method. Accordingly, an object of the present invention is to provide a method for easily and safely transporting or storing a high-concentration maleimide solution even at a low temperature by making maleimides difficult to precipitate from acrylonitrile.

[0017]

Means for Solving the Problems In order to achieve the above object, the present inventors have conducted intensive studies. As a result, the precipitation of maleimides from an acrylonitrile solution is more likely to occur near the saturation solubility as the purity of the maleimides increases. Although it is easily precipitated, the following general formula (1) is prepared in an acrylonitrile solution of a maleimide.

[0018]

Embedded image

(Wherein R ₁ and R ₂ are hydrogen and have 1 to 20 carbon atoms)
Selected from alkyl groups, phenyl groups, benzyl groups, cyclohexyl groups, viridyl groups, quinolyl groups, and those groups having a halogen substitution, a carboxy group substitution, or a nitro group substitution. )), The maleimides can be prevented from precipitating from the acrylonitrile solution, and a stable supersaturated solution that can be easily handled even at a low temperature can be produced, and the present invention has been completed. That's what it is.

By adding the compound (A) represented by the above general formula (1) to a high-concentration acrylonitrile solution of maleimides, crystallization of the maleimides can be prevented, and the maleimides can be stably and safely handled as a supersaturated solution. This is quite surprising, and it must be said that this is a great advance in handling the solution.

That is, the present invention is a method for transporting and storing maleimides, which comprises treating the maleimides in the form of an acrylonitrile solution in the presence of the compound (A) represented by the general formula (1).

The maleimides that can be transferred and stored by the method of the present invention include N-methylmaleimide, N-ethylmaleimide, N-hexylmaleimide, N-octylmaleimide, N-dodecylmaleimide, N-benzylmaleimide, and N-cyclohexyl. Maleimide, N-phenylmaleimide, N-nitrophenylmaleimide, N-methoxyphenylmaleimide, N-methylphenylmaleimide, N-carboxyphenylmaleimide, N-hydroxyphenylmaleimide, N-chlorophenylmaleimide, N-dimethylphenylmaleimide, N -Dichlorophenylmaleimide, N-bromophenylmaleimide, N
-Dibromophenylmaleimide, N-trichlorophenylmaleimide and N-tribromophenylmaleimide.

The compound to be coexisted in the acrylonitrile solution is the compound (A) represented by the general formula (1).

Specific examples of the compound which may coexist in addition to the above-mentioned compound include the following.
An oligomer and / or polymer comprising at least one selected from the group consisting of acrylonitrile, the maleimides, styrene, methylstyrene, ethylstyrene, butadiene, methacrylates, and acrylates.

The following general formula (2):

[0026]

Embedded image

The following general formula (3):

[0028]

Embedded image

And the following general formula (4):

[0030]

Embedded image

(In the general formulas (2) to (4), R ₁ and R ₂ represent hydrogen, an alkyl group having 1 to 20 carbon atoms, phenyl group, benzyl group, cyclohexyl group, viridyl group, quinolyl group, and these groups) Selected from those having a halogen substitution, a carboxy group substitution, or a nitro group substitution.), But is not limited thereto.

The compound is used in an amount of 0.01 to 20% by weight, preferably 0.1 to 10% by weight, more preferably 0.5 to 10% by weight, based on the amount of the maleimide in the acrylonitrile solution.
5% by weight.

The effect of the compound depends on the type and the amount of the compound added, but generally, the addition temperature of 1% by weight of the compound lowers the precipitation temperature of maleimides from the acrylonitrile solution over about 5 to 40 ° C. Can be.

Addition of less than 0.01% by weight is less effective. Conversely, addition of more than 20% by weight causes a problem that the polymerization reaction does not proceed promptly during polymerization and further impairs the physical properties of the final polymer. is there.

The type and amount of the compound are determined by the type of the final polymer obtained by using the acrylonitrile solution,
Of course, the selection may be made in consideration of the polymerization method, polymerization conditions, and the like.

The temperature at which the maleimides are dissolved in acrylonitrile is preferably not higher than the boiling point of acrylonitrile. Since acrylonitrile has a high vapor pressure, the acrylonitrile is usually dissolved at 40 to 60 ° C.
Handled in the range of 10-50 ° C.

As a dissolving method, basically any method can be adopted, but acrylonitrile may be added to the maleimide and the compound, or the compound and the maleimide may be dissolved in the acrylonitrile. . The maleimides used at this time may be solid or liquid.

Further, in a preferred embodiment, a method of dissolving maleimides in acrylonitrile containing an oligomer and / or polymer of acrylonitrile, an intermolecular condensate of maleamic acid and an aminosuccinimide during the production of maleimides. Thereafter, a method of mixing and dissolving maleimides containing these compounds in advance with acrylonitrile can be considered, but is not limited to these.

The concentration of the maleimides in the acrylonitrile solution is determined by the temperature at which the solution is handled, the amount of the compound added, and the like. Usually, the higher the concentration of the maleimides in the acrylonitrile solution, the lower the transportation cost, and thus the higher the concentration.
A concentration of 0 to 90% by weight is preferred.

[0040]

The present invention has been described above. The advantages obtained by the present invention are as follows.

(1) Maleimides can be easily handled as a liquid without directly contacting the human body, and transport and storage are simple and safe.

(2) A high concentration of maleimides can be stably and safely handled at a low temperature without depositing the maleimides.

(3) The transportation and storage of maleimides at a high concentration can be easily performed, so that transportation and storage costs are low.

(4) Since maleimides having a high concentration can be handled stably and safely, a final polymer having a high maleimide content can be obtained using the solution.

[0045]

The present invention will be described in more detail with reference to the following examples.

Examples 1-2 In a 500 ml flask equipped with a stirrer and a condenser,
Acrylonitrile and N-phenylmaleimide having a purity of 99.9% by weight, and the following formula (2):

[0047]

Embedded image

The precipitation temperature of N-phenylmaleimide was measured by adding the compound (a). Table 1 shows the results.

Comparative Example 1 The deposition temperature of N-phenylmaleimide was measured in the same manner as in Example 1, except that maleic anhydride was added instead of compound (a). Table 1 shows the results.

[0050]

[Table 1]

Examples 3 to 5 N-phenylmaleimide having the following composition was dissolved in acrylonitrile, and the deposition temperature at each concentration was measured. Table 2 shows the results.

N-phenylmaleimide composition N-phenylmaleimide 98.5% by weight 2-anilino-N-fe 0.5 {nylsuccinimide (molecular weight 266) N-phenylmaleamic acid 0.1} (molecular weight 191) Compound ( a) * 0.9〃 (molecular weight: 364) Compound (a):

[0053]

Embedded image

[0054]

[Table 2]

Comparative Examples 2 to 4 Measurements were made using N-phenylmaleimide having the following composition instead of N-phenylmaleimide used in Examples 3 to 5. Table 3 shows the results.

N-phenylmaleimide composition N-phenylmaleimide 99.5% by weight Maleic anhydride 0.5% (molecular weight 98)

[0057]

[Table 3]

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Kentaro Sakamoto 1-992, Nishioki, Okihama-shi, Aboshi-ku, Himeji-shi, Hyogo Japan Examiner, Nippon Shokubai Chemical Industry Co., Ltd. Himeji Research Laboratory Tamotsu Tominaga

Claims (1)

(57) [Claims] 1. A maleimide compound represented by the following general formula (1): (Wherein, R ₁ and R ₂ represent hydrogen, an alkyl group having 1 to 20 carbon atoms, a phenyl group, a benzyl group, a cyclohexyl group, a viridyl group, a quinolyl group, and halogen substitution on these groups;
It is selected from those having carboxy group substitution and nitro group substitution. A method for transporting and storing maleimides, which is handled in the form of an acrylonitrile solution in the coexistence of the compound (A) shown in (1).