JP2644934B2 - How to handle maleimides - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for handling maleimides. More specifically, coloring maleimides,
The present invention relates to a method of safely transporting or storing in a state where deterioration such as polymerization is prevented, or a method of handling such as easily charging maleimides into a reactor.

[0002]

2. Description of the Related Art Maleimides are compounds useful as raw materials for resins, medicines, agricultural chemicals and the like. Conventionally, maleimides that are solid at room temperature are generally handled in the form of powder, flakes, tablets, and the like. The maleimides in such a form include a fine powder of the maleimides. In particular, such solid maleimides are powdered during transportation, and a large amount of fine powder is generated.

[0003] Maleimides themselves are irritating to the human body. Particularly, inhalation of fine powder irritates the nasal cavity and throat, causing coughing and sneezing, and causing inflammation when left on the skin. Has no properties. Therefore, when handling maleimides containing such fine powders, strict care must be taken to avoid contact with the skin as much as possible.

Therefore, a great deal of labor is required to prevent the generation of fine powder as much as possible during the transportation of maleimides and to remove the fine powder from the maleimides after transportation.

[0005] Usually, the transport of solid substances is often carried out by filling a solid substance in a paper bag, a drum, a container, or the like. When this method is applied to the transport of maleimides, it is inevitable that the maleimides and the human body are transported. Contact is inevitable, and it is inevitable that the maleimide fine powder adheres to the human body. In addition, the transport of solid substances by pipes to avoid contact with the human body is basically difficult to block the pipes during pipe transport, and to transport these solid substances stably, Strict constraints such as shape, size and specific gravity are imposed. As described above, it must be said that there are many difficulties in the method of transporting or transferring maleimides which are solid at ordinary temperature. The same is true for the storage method.

On the other hand, in order to solve the above problems, a method has been considered in which maleimides are heated to a temperature higher than the melting point and handled in a liquid state. In this method, since the maleimides are heated to a temperature higher than the melting point, it is necessary to prevent the polymerization of the maleimides.
No. 145062, JP-A-62-143911 and JP-A-63-316767. According to these methods, the polymerization of maleimides can be effectively suppressed. However, generation of coloring impurities due to heating of maleimides cannot be completely prevented.

[0007] Therefore, when the maleimides are kept at a high temperature above the melting point and stored in a liquid state for a long period of time, there is a problem that the maleimides are colored and the commercial value is completely reduced. As described above, the conventional method for handling maleimides is not a perfect method.

[0008]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a novel method for handling maleimides.

Another object of the present invention is to provide a safe and simple method for transporting and storing maleimides without fear of generating fine powder during transportation or storage.

Still another object of the present invention is to provide a method for handling maleimides which can prevent coloring of the maleimides and maintain high quality for a long period of time.

[0011]

Means for Solving the Problems The present inventors have developed a method for stabilizing the maleimides by heating them to a temperature higher than the melting point, such as preventing the polymerization and coloring of the maleimides when handling the molten products, ie, the liquid products. As a result of intensive studies, maleimides are extremely compatible with aromatic hydrocarbons and can effectively lower the melting point of maleimides by the addition of aromatic hydrocarbons. It has been found that since the compounds can be liquefied and kept in a liquid state at a relatively low temperature, polymerization of maleimides can be prevented. In addition, the mixture of the maleimides and the aromatic hydrocarbons was heated, and as a result of intensive studies on the thermal stability such as prevention of coloring of the maleimides when handled as a liquid product, the prevention of coloring of the maleimides was in the gas phase. It has been found that this can be achieved by controlling the molecular oxygen concentration to a specific concentration or less.

[0012] That is, the above-mentioned objects are aimed at the molecular state of the gas phase.
Under an atmosphere in which the oxygen content is adjusted to 10% by volume or less
And an alkyl-N-substituted maleimide having 1 to 20 carbon atoms
, N-benzylmaleimide, cycloalkyl having 5 to 6 carbon atoms
Alkyl-N-substituted maleimides, N-phenylmaleimi
And 1 to 4 nitro, methoxy, hydroxy
A sil, alkyl, halogen or carboxyl group
From the group consisting of phenyl-N-substituted maleimides
100 parts by weight of at least one selected maleimide ,
Benzene, toluene, xylene, ethylbenzene, iso
Propylbenzene, mesitylene, naphthalene, tetrahi
Dronaphthalene, butylbenzene, sec-butylben
Zen, tert-butylbenzene, p-cymene and
At least selected from the group consisting of clohexylbenzene
1 to 60 parts by weight of one kind of aromatic hydrocarbon and a stabilizer
This is achieved by a method for handling maleimides that are solid at room temperature, characterized in that they are handled as a solution consisting of 0.0001 to 1 part by weight .

[0013] Further, the above-mentioned objects are attained by adjusting the molecular oxygen content of the gaseous phase portion to 10% by volume or less in an atmosphere containing carbon dioxide.
An alkyl-N-substituted maleimide having a prime number of 1 to 20, N-
Benzyl maleimide, cycloalkyl having 5 to 6 carbon atoms
N-substituted maleimides, N-phenylmaleimide, and
And 1 to 4 nitro, methoxy, hydroxyl groups,
F having alkyl, halogen or carboxyl groups
Selected from the group consisting of phenyl-N-substituted maleimides
100 parts by weight of at least one maleimides, benzene
, Toluene, xylene, ethylbenzene, isopropyl
Rubenzene, mesitylene, naphthalene, tetrahydrona
Phthalene, butylbenzene, sec-butylbenzene,
tert-butylbenzene, p-cymene and cyclohexane
At least one selected from the group consisting of xylbenzene
From 1 to 60 parts by weight of aromatic hydrocarbons and 0.0
It is also achieved by a method for handling maleimides which are solid at ordinary temperature, characterized in that they are handled as a melt consisting of 001 to 1 part by weight.

[0014]

Hereinafter, the present invention will be described in detail. Maleimides that can be handled such as transported or stored by the method of the present invention include, for example, N-methylmaleimide, N-ethylmaleimide, N-isopropylmaleimide, N-hexylmaleimide, N-octylmaleimide, N-dodecylmaleimide. C1-C20 alkyl-N-substituted maleimides, such as N-benzylmaleimide, N-cyclohexylmaleimide, etc.
N-substituted maleimides, N-phenylmaleimide, N-
Nitrophenylmaleimide, N-methoxyphenylmaleimide, N-methylphenylmaleimide, N-carboxyphenylmaleimide, N-hydroxyphenylmaleimide, N-chlorophenylmaleimide, N-dimethylphenylmaleimide, N-dichlorophenylmaleimide,
N-bromophenylmaleimide, N-dibromophenylmaleimide, N-trichlorophenylmaleimide, N-
Examples include, but are not limited to, phenyl-N-substituted maleimides having 1-4 nitro, hydroxyl, alkyl, halogen, or carboxyl groups, such as tribromophenylmaleimide.

The stabilizer used in the present invention may be any one used in the fields of industrial products and research reagents, and is not limited. Examples thereof include methoxybenzoquinone, p-methoxyphenol and phenothiazine. , Hydroquinone, diphenylamines, methylene blue, zinc dimethyldithiocarbamate, dialkyldithiocarbamate such as copper dimethyldithiocarbamate, copper dibutyldithiocarbamate, copper salicylate, thiodipropionate, mercaptobenzimidazole, alkyl-substituted hydroxybenzenes, alkyl Examples thereof include bisphenols, hindered phenols, phosphoric esters, phosphites, and phosphoric amides, and these stabilizers can be used alone or in combination of two or more.

In particular, at least one kind of stable selected from the group consisting of alkyl-substituted hydroxybenzenes, thiodipropionates, hindered phenols, phosphates, phosphites and phosphate amides. The agent, at a temperature above the melting point of the maleimides,
In the present invention, these stabilizers are suitably used because they are very effective in preventing coloring of maleimides. Further, a stabilizer such as at least one phosphorus compound selected from phosphoric esters, phosphites and phosphoric amides is also preferably used.

Hereinafter, various stabilizers will be specifically shown as alkyl-substituted hydroxybenzenes such as 2,2.
4-dimethyl-6-tert-butylphenol, 4-
tert-butylcatechol, 2,5-di-tert-
Butylhydroquinone, 2-tert-dibutylhydroquinone, 4,4'-thio-bis (6-tert-butyl-
m-cresol) and the like, and preferably 4-ter
t-butylcatechol and the like.

The thiodipropionic esters include:
For example, ditridecyl-3,3'-thiodipropionate, dilauryl-3,3'-thiodipropionate, ditetradecyl-3,3'-thiodipropionate, distearyl-3,3'-thiodipropionate And dioctyl-3,3'-thiodipropionate, and preferably ditridecyl-3,3'-thiodipropionate.

The hindered phenols include, for example, 2,4-bis (n-octylthio) -6- (4-hydroxy-3,5-di-tert-butylanilino)-
1,3,5-triazine, 2,2'-thiobis (4-methyl-6-tert-butylphenol), triethylene glycol-bis (3- (3-tert-butyl-5
-Methyl-4-hydroxyphenyl) propionate), pentaerythrityl-tetrakis (3- (3,5
-Di-tert-butyl-4-hydroxyphenyl) propionate), octadecyl-3- (3,5-di-t)
tert-butyl-4hydroxyphenyl) propionate, 2,2-thio-diethylenebis (3- (3,5-di-tert-butyl-4-hydroxyphenylpropionate), 1,6-hexanediol-bis (3 −
(3,5-di-tert-butyl-4-hydroxyphenyl) propionate), tris (3,5-di-ter
t-butyl-4-hydroxybenzyl) -isocyanurate, 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, N, N '-Hexamethylenebis (3,
5-di-tert-butyl-4-hydroxy-hydrocinnamamide), 3,5-di-tert-butyl-4-
Hydroxy-benzylphosphonate-diethyl ester; and the like, preferably 2,4-bis (n-octylthio) -6- (4-hydroxy-3,5-di-te
rt-butylanilino) -1,3,5-triazine,
2,2'-thiobis- (4-methyl-6-tert-butylphenol), triethylene glycol-bis-
(3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate) and the like, but are not limited thereto.

Examples of the phosphites include triphenyl phosphite, tris (nonylphenyl) phosphite, triethyl phosphite, tris (2-ethylhexyl) phosphite, tridecyl phosphite, and tris (tridecyl) phosphite. , Tristearyl phosphite, diphenyl mono (2-ethylhexyl) phosphite, diphenyl monodecyl phosphite, diphenyl monotridecyl phosphite, dilauryl hydrogen phosphite, diphenyl hydrogen phosphite, tetraphenyl dipropylene glycol diphosphite , Tetraphenyltetra (tridecyl) pentaerythritol tetraphosphite, tetra (tridecyl) -4,4'-isopropylidenediphenylphosphite, trilaurylt Thio diphosphite, bis (tridecyl) pentaerythritol diphosphite, bis (nonylphenyl) pentaerythritol diphosphite, distearyl pentaerythritol diphosphite, tris (2,4-di -tert- butylphenyl)
Examples include phosphite, hydrogenated bisphenol A / pentaerythritol phosphite polymer, hydrogenated bisphenol A phosphite polymer, and the like, and preferred is distearyl pentaerythritol diphosphite.

Examples of the phosphoric acid esters and other phosphorus compounds include hexamethylphosphoric triamide, ethyl diethylphosphonoacetate, ethyl acid phosphate, β-chloroethyl acid phosphate, butyl acid phosphate, butyl pyrophosphate, and butoxy. Ethyl acid phosphate, 2-ethylhexyl acid phosphate, di (2-ethylhexyl) phosphate, ethylene glycol acid phosphate, (2-hydroxyethyl) methacrylate acid phosphate, tris (2-chloroethyl) phosphate, tris (dichloropropyl) phosphate,
Octyl dichloropropyl phosphate, phenyldichloropropyl phosphate, trimethyl phosphate,
Triethyl phosphate, tributyl phosphate, trioctyl phosphate, tricresyl phosphate,
Triphenyl phosphate and the like can be mentioned, and preferred is tris (2-chloroethyl) phosphate and the like.

The amount of the stabilizer used in the present invention is 0.0001 to 1.0 part by weight, preferably 0.001 to 0.1 part by weight, based on 100 parts by weight of the maleimide. The type of stabilizer is selected in consideration of the type of polymer to be produced, the method of polymerization, the initiator used, and the like.

Further, by using the above-mentioned alkyl-substituted hydroxybenzenes and the above-mentioned phosphorus compounds such as phosphoric esters, phosphites and phosphoric amides in combination, the above-mentioned stabilizer can be used alone. A more excellent effect of preventing the coloration of maleimides can be obtained. The ratio is not particularly limited, but preferably the weight ratio of the alkyl-substituted hydroxybenzene to the phosphorus compound is 1: 0.1 to 1 : 1000, more preferably 1: 1 to 1: 1000. is there.

The aromatic hydrocarbons used in the present invention include, for example, benzene, toluene, xylene, ethylbenzene, isopropylbenzene, mesitylene, naphthalene, tetrahydronaphthalene, butylbenzene, sec-butylbenzene, tert-butylbenzene. , P-cymene, cyclohexylbenzene, and the like, but are not limited thereto, and may be any aromatic hydrocarbon generally used as a solvent,
The choice is made in consideration of the type of polymer to be produced, the method of polymerization, the initiator used, and the like.

In the present invention, the temperature at which the aromatic hydrocarbon solution of a maleimide is handled varies depending on the melting point or solubility of the maleimide, but is usually 30 to 120 ° C. The amount of the aromatic hydrocarbon to be added to the maleimide is appropriately determined so that the mixture of the maleimide and the aromatic hydrocarbon becomes a homogeneous solution within the temperature range. The amount varies depending on the type of the maleimide or the aromatic hydrocarbon, but is 1 to 60 parts by weight of the aromatic hydrocarbon per 100 parts by weight of the maleimide.

In the present invention, it is preferable that the concentration of molecular oxygen in the gas phase is suppressed to 10% by volume or less. According to the findings of the present inventors, there is a clear relationship between the coloring of maleimides and the concentration of molecular oxygen in the gas phase, and under normal air atmosphere, the maleimides are colored at a remarkably fast rate and are particularly stable. Under the condition of high molecular oxygen concentration in the absence of the agent, this coloring is promoted. In addition, even in the presence of the stabilizer, the molecular oxygen concentration in the gas phase becomes 10% by volume.
If it exceeds 3, the maleimides are similarly colored, and the commercial value is significantly impaired.

When a maleimide is handled as a solution of an aromatic hydrocarbon in a liquid state under heating conditions, a molecular oxygen concentration of 10% by volume or less in the gas phase is effective for preventing coloration. The lower the value, the better the results. In particular, it is more preferable that the gas phase is replaced by at least one inert gas selected from the group consisting of nitrogen, carbon dioxide, helium and argon.

[0028]

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

Examples 1 to 53 and Comparative Examples 1 to 3 By changing various conditions such as the type of maleimides, the type of polymerization inhibitor, the amount added and the molecular oxygen concentration in the gas phase, the maleimides and the polymerization inhibitor were changed. The agent and the aromatic hydrocarbons were measured in a sealable stainless steel container and heated in an oil bath at a predetermined temperature. At this time, the gas phase was replaced with nitrogen gas, and the molecular oxygen concentration in the gas phase was adjusted to a predetermined concentration. After a lapse of 1 to 3 months, the container was taken out and the appearance of the solution was visually observed. Further, the maleimides after heating were subjected to solution polymerization with styrene, and the appearance of the resulting polymer was visually observed.
The results are shown in Table 1 (using alkyl-substituted hydroxybenzenes as stabilizer), Table 2 (using thiodipropionic esters as stabilizer), Table 3 (using hindered phenols as stabilizer), and Table 4 (using hindered phenols as stabilizer). Phosphates and phosphites are used as stabilizers), Table 5 (combination use of alkyl-substituted hydroxybenzenes and phosphorus compounds) and Table 6 (Comparative Example).

Reference Example 1 Synthesis of Polymer 44 g of methyl ethyl ketone was charged into a 1-liter four-necked flask equipped with a stirrer, a cooler, a nitrogen gas inlet tube and a dropping funnel, and the gas phase was sufficiently purged with nitrogen to 80 ° C. Heated. N-phenylmaleimide 9 was prepared by using the o-xylene solution of N-phenylmaleimide obtained in Example 1.
A mixed solution of 6.55 g, 58.07 g of styrene and 460 g of o-xylene was prepared, and a solution of the mixed solution, 0.77 g of azoisobutyronitrile and 11 g of o-xylene was kept at an internal temperature of 80 ° C. for 4 hours. And drop it for another 1
Stirring was continued for hours. Next, the reaction product was cooled, transferred to 2 liters of methanol, filtered and dried to obtain a white powdery polymer.

Using the maleimide solution obtained in each of the examples in the same manner, the molar ratio of maleimide to styrene was 1
The corresponding polymer was synthesized with azoisobutyronitrile being 0.5% by weight based on the monomer, and the appearance was determined. The results are shown in Tables 1 to 5.

Reference Example 2 N-phenylmaleimide (PMI) toluene and o
-The solubility in xylene was measured. The results are shown in FIGS. 1 and 2, respectively.

[0033]

[Table 1]

[0034]

[Table 2]

[0035]

[Table 3]

[0036]

[Table 4]

[0037]

[Table 5]

[0038]

[Table 6]

[0039]

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

(1) Maleimides having a strong stimulus to the human body can be handled in liquid form, not in powder form, so that maleimides can be handled safely and easily.

(2) The maleimides can be stored in a liquid state with high quality for a long period of time.

(3) When a polymer is produced using the maleimides held in a liquid state, coloring of the product is hardly observed and a high-quality final product can be obtained.

(4) Maleimides are ABS resin, AAS
It is widely used as a heat resistance improver for resins, AS resins, ACS resins, etc., and by selecting appropriate aromatic hydrocarbons to be added to maleimides in advance,
The solution can be used as it is for these polymerization reactions.

As described above, according to the method of the present invention, it is possible to store and transport maleimides in a liquid state while maintaining safe and high quality, and to use the maleimides solution as it is in the polymerization reaction. Is also possible.

[Brief description of the drawings]

FIG. 1 is a graph showing the solubility of N-phenylmaleimide (PMI) in toluene.

FIG. 2 is a graph showing the solubility of N-phenylmaleimide (PMI) in o-xylene.

Claims (4)

(57) [Claims] 1. The method according to claim 1 , wherein the molecular oxygen content of the gas phase is 10% by volume.
In an atmosphere adjusted as follows, an Al having 1 to 20 carbon atoms
Kill-N-substituted maleimides, N-benzylmaleimi
C, cycloalkyl-N-substituted maleimis having 5 to 6 carbon atoms
, N-phenylmaleimide, and 1-4 nitro
B, methoxy, hydroxyl, alkyl, halo
Phenyl-N-substitution having a gen or carboxyl group
100 parts by weight of at least one maleimide selected from the group consisting of maleimides , benzene, toluene, xy
Len, ethylbenzene, isopropylbenzene, mesit
Len, naphthalene, tetrahydronaphthalene, butyl
Senzen, sec-butylbenzene, tert-butylbenzene
From Zensen, p-cymene and cyclohexylbenzene
At least one aromatic hydrocarbon selected from the group consisting of:
1 to 60 parts by weight and 0.0001 to 1 part by weight of stabilizer
A method for handling maleimides which are solid at room temperature, characterized in that they are handled as a solution. 2. The molecular oxygen content of the gas phase is reduced to 10% by volume.
In an atmosphere adjusted as follows, an Al having 1 to 20 carbon atoms
Kill-N-substituted maleimides, N-benzylmaleimi
C, cycloalkyl-N-substituted maleimis having 5 to 6 carbon atoms
, N-phenylmaleimide, and 1-4 nitro
B, methoxy, hydroxyl, alkyl, halo
Phenyl-N-substitution having a gen or carboxyl group
100 parts by weight of at least one maleimide selected from the group consisting of maleimides , benzene, toluene, xy
Len, ethylbenzene, isopropylbenzene, mesit
Len, naphthalene, tetrahydronaphthalene, butyl
Senzen, sec-butylbenzene, tert-butylbenzene
From Zensen, p-cymene and cyclohexylbenzene
A method for handling maleimides which are solid at room temperature, characterized in that they are handled as a melt comprising 1 to 60 parts by weight of at least one aromatic hydrocarbon selected from the group consisting of 0.0001 to 1 part by weight of a stabilizer. 3. The stabilizer according to claim 1, wherein the stabilizer is at least one selected from the group consisting of alkyl-substituted hydroxybenzenes, thiodipropionates, hindered phenols, phosphates, phosphites and phosphate amides.
The method for handling maleimides according to claim 1 or 2, which is a kind of stabilizer. 4. A stabilizer in which at least one selected from alkyl-substituted hydroxybenzenes and at least one phosphorus compound selected from the group consisting of phosphoric esters, phosphites and phosphoric amides. 4. The method for handling maleimides according to claim 3, wherein the method is used in combination.