JPH013167A - Method for producing maleimides - 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 application field) The present invention relates to a method for producing maleimides.

Maleimide compounds are useful compounds as raw materials for resins, pharmaceuticals and agricultural chemicals, and the present invention provides an advantageous method for producing them.

(Prior Art) Methods for producing maleimides have been studied for a long time.

The most common method is to produce maleimide by dehydrating maleamic acid using a dehydrating agent such as acetic anhydride, for example, as disclosed in US Pat.
It is also disclosed in No. 36 Specification-1.

That is, this is a method in which maleic anhydride and an amine compound are reacted, and the resulting maleamic acid is dehydrated and ring-closing imidized in the presence of acetic anhydride and 1-lium acetate.

This method requires more than the equivalent amount of expensive acetic anhydride to maleamic acid in the imidization reaction, and also requires a large amount of water to separate and recover the maleimide produced from the imidization reaction solution. As a result, a large amount of wastewater containing acetic acid is produced, which has the disadvantage of requiring a large amount of cost to detoxify it. For these reasons, this method is too expensive to industrially produce imide compounds.

Also, as in the specification of Japanese Patent Application Laid-open No. 53-68770,
Maleic anhydride and an amine compound are reacted in an organic solvent, and the resulting maleamic acid is subjected to a dehydration ring-closing reaction in the coexistence of an aprotic polar solvent such as dimethylformamide or dimethylsulfoxide and an acid catalyst without being exposed to the vehicle. There is a way. However, this method uses a large amount of expensive and toxic aprotic polar solvents such as dimethylformamide, which increases the production cost of maleimide. There are problems such as increased loss due to deterioration of the solvent, and furthermore, it is difficult to remove these aprotic polar solvents from the product maleimide due to their high boiling points. Therefore, it cannot be said that it is an excellent method.

Furthermore, as disclosed in Japanese Patent Publication No. 51-40078, solvents such as toluene, xylene, and chlorobenzene having a boiling point of 80°C or higher and chlorosulfonic acid, p-toluenesulfonic acid, and benzenesulfonic acid are used as diluents. There is also a method of carrying out thermal dehydration ring closure together with an acid catalyst such as orthophosphoric acid, pyrophosphoric acid, or phosphorous acid, and distilling the water forming the FR structure out of the system by azeotropy with the solvent. This method is superior to the above two methods in that it not only does not require a large amount of an expensive dehydrating agent such as acetic anhydride, but also that the maleimide produced is easy to separate and recover.

However, in this method, chlorsulfone M,
A relatively large amount of expensive acid catalysts such as D-t-luenesulfonic acid, benzenesulfonic acid, orthophosphoric acid, pyrophosphoric acid, phosphorous acid, etc. are used, and the yield of maleimides is low, making it difficult to use as an industrial production method. is not economically satisfactory.

As described above, the conventionally proposed methods for producing maleimides have many problems and are not satisfactory for industrial implementation.

(Objective of the present invention) Thus, the object of the present invention is to provide a method for producing maleimides in a high yield, at low cost, in a safe and simple manner as compared to the above-mentioned methods.

(Means for Solving the Problems) The present inventors have been conducting research on the synthesis reaction of maleimides for a long time. In particular, we have been intensively studying catalysts used in ring-closing imidization reactions using acid catalysts (also in water-insoluble or water-immiscible inert organic solvents).

According to the findings of the present inventors, in the rAffl imidization reaction using a water-insoluble or water-immiscible inert organic solvent, a liquid acid J3 insoluble in an organic solvent and/or a raw material amine and an acid are used as a reaction catalyst. The available amine salts are the most effective.

Maleamic acid is present in the organic solvent layer, and the above-mentioned catalyst is added to this solvent layer for the imidization reaction. These catalysts are insoluble in the solvent and form another liquid phase different from the organic solvent layer in the reactor.

Therefore, in order for the imidization reaction to proceed in a good manner, it is essential that the maleamic acid contacts the catalyst layer efficiently.

However, even if attempts are made to increase the contact area by increasing the amount of liquid acid catalyst in order to improve the contact efficiency between maleamic acid and the catalyst, this objective cannot be achieved because the liquid acid catalyst particles tend to associate. There wasn't.

Not only that, but the number of side reactions within the catalyst layer increases as the spacing between the catalysts increases, and as a result, it is not possible to increase the selectivity of the imidization reaction.

Furthermore, it is difficult to keep the stirring conditions of the reactor constant because as the acid catalyst is used repeatedly, the physical properties of the acid catalyst such as purification and specific gravity change due to the influence of by-reactants in the acid catalyst. Despite this, the dispersion status of the acid catalyst changed each time, making it impossible to reproducibly reproduce the reaction state and yield. In addition, because the separation conditions of the acid catalyst differ each time due to such changes in catalyst properties, there is a problem in that a great deal of labor is required to separate and reuse the acid catalyst.

Therefore, the present inventors have found that the contact interface area between the maleamic acid and the acid catalyst can be easily controlled by supporting the acid and/or the amine salt obtained from the raw material amine and the acid on a solid carrier. Since a large contact area can be obtained with a small amount of catalyst, the selectivity of the imidization reaction can be significantly increased, and the reaction can be reproducibly performed even if the catalyst is repeatedly used for the reaction, so the catalyst properties are stable and the reaction liquid is stable. The present invention was completed by discovering that it is possible to easily separate .

That is, the present invention provides a method for producing maleimides, characterized in that during the production of maleimides, a catalyst in which an acid and/or an amine salt obtained from a raw material amine and an acid is supported on a solid carrier is used as a catalyst. be.

The most distinctive feature of the present invention is that instead of using liquid acid catalysts (such as sulfuric acid, orthophosphoric acid, and pyrophosphoric acid) in the ring-closing imidization reaction, a so-called supported catalyst in which these liquid acid catalysts are supported on a solid carrier is used. It is in.

In addition, the maleamic acid used in the present invention, which can be reacted in the presence of a metal or a stabilizer in the ring-closing imidization reaction, is usually used with maleic anhydride.
It is easily obtained by reaction with amines, and the following -
Represented by a mathematical formula.

CI-1-C-01-1 CH-C-N +-1-R In the formula, R is an alkyl group having 1 to 20 carbon atoms, a noenyl group, a benzyl group, a cyclohexyl group, a pyridyl group,
It is selected from quinolyl groups and those having halogen substitution on these groups, and those having tro group substitution on carboxyl group substitution. ) In particular, the following primary amines are suitable as raw materials for the maleamic acid used in the present invention.

Methylamine, -[puramine, n-propylamine,
Isopropylamine, n-butylamine.

5ec-butylamine, tert-butylamine, n
-hexylamine, n-dodecylamine, allylamine, benzylamine, cyclohexylamine, aniline,
Nitroaniline, amine phenol, aminobenzoic acid,
Anisidine, ■Toxyphenylamine, monochloroaniline, dichloroaniline.

1. Luidin, xylidine, ■Deruayu 92, etc.

The synthesis of maleamic acid is almost stoichiometric;
Preferably, 1 mole of amine is used per mole of 7-leic acid anhydride, but it is possible to react in a range of 0.8 to 15 moles, preferably 0.9 to 1.2 moles.

If the amine compound is in excess of maleic anhydride, it is necessary to use a larger amount of acid catalyst than necessary when directly subjecting it to the imidization reaction, and side reactions may be generated in the imidization reaction. The above range is preferable since a large amount of substances are produced and the yield of the imidization reaction becomes low.

Furthermore, the organic solvent used in the present invention is preferably a solvent that is insoluble or immiscible in water, inert, and unrelated to the reaction, such as benzene.

1 to 1,000 ton, petroleum distillate with a boiling point of 50 to 120°C, xylcins, ethylbenzene, isopropylbenzene, cumene, mesitylene, tert-butylbenzene, pseudocumene, 1 to helimedyl ↑ 4 non, octane, detrachloroethane, nonane , chlorobenzene, ni〇-delcyclo↑1non, petroleum distillate with a boiling point of 120-170°C, ■-dichlorobenzene, 5ec-butylbenzene, p-dichlorobenzene, decane, p-cymene.

0-dichlorobenzene, butylbenzene, decahydronaphthalene, tetrahydronaphthalene.

Dodecane, naphthalene, cyclohexylbenzene.

There are petroleum fractions with a boiling point of 170 to 250°C. The amount of the solvent to be used is 1 to 20 times (volume), preferably 3 to 7 times the amount of maleamic acid, in order to carry out the reaction smoothly and satisfy the economic regulations.

Further, a material with a boiling point suitable for the reaction conditions is selected while taking into consideration the degree of solubility of the maleimides, price, handling and processing, etc. Furthermore, when considering the separation of the maleimide from the solvent after the reaction is completed, it may be advantageous to use a low boiling point solvent and carry out the reaction under pressure.

Sulfuric acid, orthophosphoric acid, and metaphosphoric acid are used as catalysts.

Basic acids or polybasic acids such as pyrophosphoric acid and/or
Alternatively, an amine salt obtained by neutralizing amines, which are raw materials for producing maleimides, supported on a solid carrier may be used.

Solid carriers include natural minerals such as kaolins, clays, talcum, quartz, bentonite, montmorillonite, diatomaceous earth, etc., synthetic minerals such as highly dispersed silicic acid, alumina, silicates, activated carbon, gypsum, red iron oxides, etc. Titanium, silica, silica-alumina, zirconium oxide, etc.; natural rocks such as calcite, marble, pumice, sepiolite, dolomite, etc. are used.

These inorganic carriers are powdered or granulated.

It is used in the form of granules or honeycombs obtained by classification.

It is also possible to use organic carriers, and particulate carriers such as polyfluorocarbon, polystyrene, and phenolic resins can be used.

Particularly good results can be obtained when the carrier is porous such as diatomaceous material, silica gel, etc. For example, an example of a commercially available diatomaceous earth is Radiolite (
(manufactured by Showa Kagaku Kogyo Co., Ltd.), silica gels such as Caract and Thyroid.

Microbead silica gel (manufactured by Fuji Davison Chemical Co., Ltd.), Wakoglu (Wako Junso Industries Co., Ltd.),
etc. can be given.

Usually, the amount of acid catalyst supported on the carrier varies depending on the physical properties of the carrier used, but it is preferably 0.5 to 500 m%, preferably 5 to 200 m%, particularly preferably 1
The amount is from 0 to 100% by weight.

In addition, any of the commonly used methods such as impregnation method and spraying method can be adopted as a method for supporting.
The catalyst may be supported directly on the carrier, or may be supported in an organic solvent or an aqueous solution.

When using an amine salt obtained by neutralizing a raw material amine and an acid as a catalyst, either alone or in the form of a mixture with an acid, the acid catalyst may be supported on a carrier and then reacted with the amine. A mixture of salt and acid may be prepared in advance and then supported. However, in the case of using an amine salt alone, since the amine salt is solid at room temperature, it is necessary to support it in the form of an aqueous solution.

The amount of these catalysts used is 2 to 400 mol%, preferably 20 to 2 mol%, based on the maleamic acid contained in the acid content.
The range is 0.00 mol%. Further, part or all of the acid serving as a catalyst may be neutralized with an amine.

These supported catalysts can be used by being added to a stirring reaction vessel in the form of a powdered catalyst, or may be used as a fixed bed by filling a flow-through reaction tube in the form of a granular catalyst.

Further, depending on the case, a metal-containing compound or a stabilizer may be allowed to coexist in the reaction system for the reaction. The metal-containing compounds used at this time include zinc and chromium.

At least one metal oxide selected from the group consisting of palladium, cobalt, nickel, iron and aluminum,
Vinegar M salt, maleate salt, amber M salt.

It is selected from nitrates, phosphates, chlorides and sulfates, among which zinc acetate is particularly effective. The amount of these metals used is 0.005 to 0.5 mol%, preferably 0.01 to 01 mol%, based on 1 mol of maleamic acid.

Furthermore, meth-1-xybenzo L-non is used as a stabilizer.

p-methoxyphenol, phenodeazine, hydroquinone, alkylated diphenylamines, medilene blue
, tert-butylcatechol butylhydroquinone, zinc dimethyldithiocarbamate, copper dimethyldithiocarbamate, copper dibutyldithiocarbamate, copper salicylate, thiodipropionic acid sters, mercaptobenzimidazole, triphenylphosphite, alkylphenols, alkylbisphenols, etc. is used.

The effects of these stabilizers play a role in allowing the maleimide produced by the imidization reaction to exist stably without deterioration even under the high temperature of the imidization reaction.

Regarding the amount added, adding a trace amount will reduce the effect, and conversely, adding an excessive amount is not desirable because it may cause a problem of mixing into the product. Therefore, the amount of these used is 0.005 to 0.05-syl% based on 1 mole of maleamic acid.
It is.

In the eggplant method of the present invention, first, an amine compound is added to a solution of maleic anhydride in an organic solvent, and the mixture is heated at 150°C or higher.
, preferably at 30 to 120°C for 15 to 120 minutes to obtain maleamic acid. Next, the mixed catalyst of the salt and acid described above or the mixed catalyst layer of the salt and acid separated from the reaction system is added without adding maleamic acid, and if necessary, a metal-containing compound and/or Alternatively, add a stabilizer and heat at 120 to 250°C, preferably 130 to 220°C, for 1 minute to 15 hours, continuously distilling the generated water out of the system as a solvent and 'dt compound. Maleimides can be produced in high yields by performing the reaction batchwise or by distilling them out of the system after the reaction is complete. It is possible to build A.

(Effects of the Invention) The present invention has been described above, and the advantages of the present invention include 1 size small size and A3 size C.

■ Acid LJ3J, -bi/yota, or raw amine The amine salt obtained from the acid is supported on 11 solid bodies and the tactile thread has a catalytic effect with high selectivity for the ring-closing imidization reaction. 1q of high-purity lα maleimide in high yield
can be done.

(1) Because the catalyst is supported on a solid body, it is easy to separate the reaction liquid and the catalyst, so the reaction can be easily made continuous, and the productivity of the process can be greatly improved.

■ Catalyst loss is small and catalyst cost is negligible.

As shown in (■) to (■) above, according to the present invention, maleimides can be produced inexpensively, completely, and easily. A can be built.

(Examples) The present invention will be further elaborated by Examples below, but the present invention is not limited by these.

Example 1 20 g of orthophosphoric acid was added to a 200 cc beaker, and then 30 iJ of diatomaceous earth (Radiolye 1 to #200) was added.
(manufactured by Showa Kagaku Chogyo Co., Ltd.) was added to make diatomaceous earth support Δrusolinic acid.

temperature t1, a cooling tube equipped with a water separator, a flask equipped with dropping row 1~ and a stirrer], maleic anhydride 55
A solution prepared by dissolving 50g of xylene in 50g of xylene was charged. Next, the temperature inside the flask was adjusted to 80 DEG C., and a solution prepared by dissolving 50 g of aniline in 400 g of xylene was added little by little over 30 minutes to synthesize a xylene slurry of N-phenylmaleamic acid.

A catalyst prepared in advance in a beaker was added to the slurry liquid thus obtained, and the mixture was reacted at 140°C for 3 hours.

After the reaction was completed, the reaction solution was separated from the catalyst layer. After that 8
After cooling to 0° C. and washing with water, xylene was distilled off under reduced pressure to obtain 83 g of N-phenylmaleimide crystals. The purity of the crystals was measured using a liquid column 1]71 graph and was found to be 874% by weight, corresponding to a yield of 78.0% based on aniline.

Example 2 In Example 1, acid-resistant zinc 0,034 was used to aid the imidization reaction.
The procedure of Example 1 was repeated except that 001 g of copper dibutyldidiolbamate was added, yielding 93 g of N-phenylmaleimide crystals. When the pure melon of this l'lJ1 product was measured using liquid chroma 1 by graphography, it was 9
The yield was 4.3% by weight, corresponding to 94.3% by mole based on aniline.

Example 3 100 g of xylene in 300 cc My A7-Flass]
Lusolin l'l 20q was dispersed. Next, the same diatomaceous earth used in Example 1 was added to make the diatomaceous earth support orthophosphoric acid. Next, 9.5 g of aniline was reacted with I.
child.

The same procedure as in Example 2 was carried out except that this was used as a catalyst for the imidization reaction, and 929 was obtained.

The purity of this crystal was measured by liquid chroma 1-graphie and was found to be 98.5%, which corresponds to a yield of 97.5% based on aniline.

After the completion of the reaction, the next imidization reaction was repeated 20 times with the catalyst left in the reactor (.) and the second mark f+.The reaction yield at the 20th time was 981 mol%, and The properties of the catalyst after the completion of the reaction were the same as those in the first reaction.

Comparative Example 1 The same operation as in Example 1 was repeated except that orthophosphoric acid was not supported on diatomaceous earth. As a result, 82 g of N-phenylmaleimide crystals were obtained. The purity of this crystal was measured by liquid chromatography and was found to be 74.8% by weight, corresponding to a yield of 66.0% by mole based on the raw material aniline.

Comparative Example 2 The same operation as in Example 2 was repeated except that orthophosphoric acid was not supported on diatomaceous earth, and 85 g of N-phenylmaleimide crystals were obtained.

The purity of this crystal was determined by liquid chromatography.
It was determined to be 902% by weight, and the yield of b corresponds to 80.5 mol% based on aniline.

Comparative Example 3 When the same operation as in Example 3 was repeated except that orthophosphoric acid was not supported on diatomaceous earth in Example 3, N-
90g of crystals of 7nilmaleimide were obtained. The purity of this crystal was measured by liquid chromatography and was found to be 91.
．． 7% by mole, which corresponds to 88.8% by mole with respect to aniline.

Example 4 Ortholin 1% 960 in a 300cc Meyer flask
60 g of a granular silica gel carrier (Carryact-30 manufactured by Fuji Davison Chemical Co., Ltd.) was added thereto and stirred to coat the 414 body with ID u of acid.

Subsequently, ioog of oxoxylene was added, and 37 g of hexylamine was added dropwise to the cooled A7-Fras in a water bath to convert a portion of the supported acid into an amine salt.

On the other hand, in a flask equipped with a thermometer, a cooling tube with a water separator, a dropping funnel and a stirrer, add ortho-xylene 100
g was charged, maleic anhydride 1009 was added thereto, and the temperature inside the flask was raised to 100° C. to dissolve the maleic anhydride.

Then, a solution of 100 g of cisifhexylamine dissolved in ortho-xylene 600 (] was added dropwise in its entirety over 1 hour with stirring to synthesize a slurry of N-cyclohexylmaleamidic acid in oxoxylene.

Next, the entire amount of the above-mentioned supported catalyst and 0.1 g of copper dibutyldithiocarbamate were added to this slurry liquid, and the mixture was heated and kept at 143°C with stirring, while water produced by the reaction was distilled out of the system together with oxoxylene. Allowed time to react.

After the reaction was completed, the yield was determined by analyzing N-cyclohexylmaleimide in the reaction solution by gas chromatography, and the yield was 978 mol % based on the raw material cyclohexylamine.

Example 5 Sulfuric acid toog was added to a 500 cc beaker, and 200Ω of silica gel (Wako Tsumugi Wako Gel-C100) was added and stirred to support the acid catalyst on the silica gel. On the other hand, a reactor was prepared in which a 1 J glass flask was equipped with a thermometer, a stirrer, and a water separator.

Next, a solution prepared by dissolving 53 g of maleic anhydride powder in 50 g of p-cymene was charged into the reactor. -21 = Next, the temperature inside the reactor was adjusted to 130°C, and 30 g of a solution of 40 g of n-butylamine dissolved in 40 g of p-cymene was added.
It was added dropwise little by little over several minutes to synthesize a slurry liquid of N-(n-butyl)maleamic acid.

(To the slurry obtained by
．． 065 (l) and the produced water was heated to 180°C.
- The reaction was allowed to proceed for 1 hour while distilling off the cymene.

After the reaction was completed, the concentration of N-(butyl)maleimide in the reaction solution was measured and the reaction yield was determined to be 1, 804 mol % based on the raw material n-butiamine.

Claims (1)

[Claims] (1) When producing maleimides by dehydrating and ring-closing maleamidic acids obtained from maleic anhydride and primary amines in an organic solvent, an acid and/or an amine salt obtained from a raw material amine and an acid are used as a catalyst. 1. A method for producing maleimides, comprising using a catalyst supported on a solid carrier.