JPS587621B2 - Method for producing N-(hydroxyphenyl)maleimides - Google Patents

Description

Detailed Description of the Invention The present invention is based on the general formula (■) C, where R' is H, CH8, C2Ha, F, CI, Br.
, ■, and n represents an integer of 1 to 5.

) The present invention relates to a method for producing N-(hydroxyphenyl)maleimide represented by:

More specifically, the general formula (1) (wherein R represents a c1 to C7 alkyl group and a phenyl group, R' represents H, CH3, C2H5, F, CI, Br,
(2), and n represents an integer of 1 to 5.

) is hydrolyzed using a sulfur or phosphorus oxyacid under a temperature condition of 0 to 150°C. , R' is H, CH3, C2H5, F, CI, Br
, ■, and n represents an integer of 1 to 5.

) The present invention relates to a method for producing N-(hydroxyphenyl)maleimides represented by:

N-(hydroxyphenyl)maleimide obtained by the method of the present invention is an imide having a double bond, and it is also an excellent resin with rich functionality as a reactive material that takes advantage of the high reactivity of the hydroxyl group it has. Including intermediate raw materials, homopolymers, polymers with unsaturated compounds such as styrene or P-vinylphenol, thermosetting resins with excellent properties such as heat resistance and dimensional stability obtained by reaction with epoxy resins, Modifiers such as polyamine-bismaleimide prepolymers, epoxy-modified bismaleimide resins or phenolic resins, photosensitive resins, impregnated varnishes, paints,
It is an extremely useful compound industrially with a wide range of uses, including copper-clad laminates, crosslinking agents, vulcanizing agents, and adhesives that exhibit remarkable adhesive properties.

Generally, triethylamine,
Using sodium acetate as a catalyst and acetic anhydride as a dehydrating agent,
A method is known in which maleic anhydride is allowed to act on an amine compound.

However, if this production method is applied to a nuclear-substituted amine compound having a hydroxyl group, the hydroxyl group is first esterified, and then the cyclization condensation reaction proceeds, due to the high reactivity of the hydroxyl group. (Ninore) Maleimides cannot be obtained.

Furthermore, catalysts effective for the imidization reaction, such as bases such as N-dimethylbenzylamine, inquinoline, triethylenediamine, pyridine, and N-methylmorpholine;
as well as effective dehydrating agents such as propionic anhydride,
Even when an acid anhydride such as butyric anhydride or benzoic anhydride is used, the hydroxyl group is first esterified and then a cyclization condensation reaction occurs, or the reaction hardly proceeds and f,N-(
It has no effect on the production of hydroxyphenyl)maleimides.

Therefore, N-(hydroxyphenyl)maleimides can be produced by transesterification of maleimides obtained by the above method with esterified hydroxyl groups with alcohols, such as the N-(
A process for obtaining N-(4-hydroxyphenyl)maleimide from methyl alcohol tonoresterification reaction of 4-acetoxyphenyl)maleimide has been adopted.

However, this synthesis method requires a transesterification reaction as long as 14 hours, and the results of detailed follow-up tests show that the yield of N-(4-hydroxyphenyl)maleimide in a transesterification reaction with methanol for 21 hours is As low as 38%,
In addition, it is necessary to use a large amount of methanol, making it an uneconomical and extremely disadvantageous method from an industrial perspective.

The present inventors have proposed an N method that overcomes the drawbacks of these conventional methods.
-(Hydroxyphenyl)maleimide As a result of intensive research on the production method, we found that N-(hydroxyphenyl)
If maleimide ester compounds are hydrolyzed using sulfur or phosphorus oxyacid under relatively mild temperature conditions of 0 to 150°C, N-(hydroxyphenyl)maleimides can be produced in high purity and high yield in a short time. The present invention was completed based on the discovery that the present invention can be obtained by

N-(hydroxyphenyl) used in the method of the invention
The maleimide ester compound has the general formula (I) (wherein R
and R' have the same meanings as above), and N-(4-acetoxyphenyl)maleimide, N-( 2-acetoxyphenyl)
Maleimide, N-(4-penzoyloxyphenyl)maleimide, N-(4-jtyryloxyphenyl)maleimide, N-(4-propionyloxyphenyl)maleimide, N-(4-acetoxyphenyl) ,6-dibromphenyl)maleimide,N-(4-acetoxy3,6-
These include dimethylphenyl)maleimide, N-(3.5-cyacetoxyphenyl)maleimide, and the like.

The target compound produced by the method of the present invention has the general formula (■) (wherein R' is
These are N-(hydroxyphenyl)maleimides represented by (having the same meaning as above).

Specifically, the method of the present invention involves dissolving an N-(hydroxyphenyl)maleimide ester compound in a sulfur or phosphorus oxyacid under relatively mild temperature conditions of 0 to 150°C, and then dissolving this solution in water. This is a production method in which hydrolysis is carried out by gradually injecting the solution into an aqueous solution, and crystals of N-(hydroxyphenyl)maleimide precipitated in the aqueous solution are separated and obtained by a known method.

As described above, the method of the present invention is characterized in that a sulfur or phosphorus oxyacid solution of an N-(hydroxyphenyl)maleimide ester compound is injected into water and hydrolysis is simultaneously carried out.

According to the production method of the present invention, N-(hydroxyphenyl)
Compared to the conventional method of converting the esterified hydroxyl group of an N-(hydroxyphenyl)maleimide ester compound into a hydroxyl group through a transesterification reaction that takes a long time and uses a catalyst, maleimides can be produced by simply converting sulfur or phosphorus into a hydroxyl group. It can be produced and obtained by an extremely simple unit operation of dissolving it in oxyacid and immediately pouring it into ice water or cold water.

However, the yield of the obtained N-(hydroxyphenyl)maleimides is high, and the N-(hydroxyphenyl)maleimides precipitated in an aqueous solution can be easily separated and purified by known operations such as centrifugation. be able to.

Therefore, the present invention is an industrially extremely economical method for producing N-(hydroxyphenyl)maleimides.

The sulfur or phosphorus oxyacids used in the method of the invention include sulfuric acid, thiosulfuric acid, sulfurous acid, orthophosphoric acid, orthophosphorous acid or pyrophosphoric acid.

Usually, these compounds are used alone, but two or more kinds may be used in combination.

In the method of the present invention, a sulfur or phosphorus oxyacid plays the role of a solvent, so that no reaction solvent is particularly required.

However, in order to improve the solubility of N-(hydroxyphenyl)maleimide ester compounds, inert dimethylformamide, dimethylacetamide, dimethylsulfoxide or N-methyl-2-pyrrolidone may be used as a reaction solvent. good.

N-(hydroxyphenyl) used in the method of the invention
The amount of the maleimide ester compound is not particularly limited, but when using a sulfur or phosphorus oxyacid, or a sulfur or phosphorus oxyacid and a reaction solvent (hereinafter abbreviated as reaction solvent solution), the amount of the maleimide ester compound is Within the range of saturation solubility at the operating temperature, preferably 8 of the saturation solubility considering the solution stability of the N-(hydroxyphenyl)maleimide ester compound and the time required for dissolution.
The range is from 0 to 90.

To carry out the method of the present invention, the dissolution temperature of the N-(hydroxyphenyl)maleimide ether compound in the sulfur or phosphorus oxyacid or reaction solvent solution is 0 to 1.
The temperature is in the range of 50°C, preferably 20 to 80°C.

If the temperature is below 0°C, the solubility of the sulfur or phosphorus of the N-(hydroxyphenyl)maleimide ester compound in the oxyacid or reaction solvent solution is low, making it uneconomical.

On the other hand, at temperatures above 150°C, N-(hydroxyphenyl)
Maleimide ester compounds cause a side reaction with sulfur or phosphorus oxyacids, reducing the yield of the target compound, and when the solution is injected into water to precipitate the target compound, due to cooling of the solution and large heat of dilution. When the temperature of water is significantly raised, the water is boiled and at the same time various side reactions are induced in the aqueous solution, resulting in a significant decrease in the yield of the target N-(hydroxyphenyl)maleimides. death,
Moreover, the separation and purification operation of the target product from the by-products becomes extremely complicated.

The dissolution time of the sulfur or phosphorus of the N-(hydroxyphenyl)maleimide ester compound in the oxyacid or reaction solvent solution depends on the type of ester compound, the amount used, the dissolution temperature, and the stirring speed. 30 minutes to 5 hours is sufficient to dissolve 80 to 90 pieces.

The water used to inject the solution of the N-(human o4cyphenyl)maleimide ester compound and its amount are not particularly limited, but the temperature of the water should be in the range of 0 to 30°C in order to suppress the temperature rise of the aqueous solution due to the generation of heat of dilution. It is also possible to use ice water or ice alone in addition to water.

In addition, some N-(hydroxyphenyl)maleimides include compounds that are slightly soluble in water, and in the case of these compounds, well-known salting-out compounds that have a salting-out effect are used to improve the efficiency of crystal precipitation in water. Compounds such as sodium chloride, sodium sulfate, calcium chloride, etc. are dissolved in cold water, or N-(hydroxyphenyl)maleimites dissolved in water are extracted with an extraction solvent such as ether, benzene, toluene, xylene, etc. It is also possible to collect it.

Compared to the conventional transesterification method of N-(hydroxyphenyl)maleimide ester compound, which requires a long time and complicated steps, the method of the present invention is that the compound is dissolved in sulfur or phosphorus oxyacid, etc. and then immediately dissolved in cold water. The process of precipitating the target compound by injecting it into the liquid and separating and drying it is sufficient, and it can be said to be an extremely simplified manufacturing method.

According to the method of the present invention, N-(hydroxyphenyl)maleimides can be produced in high yield and with high purity, so it is an extremely useful production method industrially.

The present invention will be explained below with reference to Examples.

Example l N-(4-acetoxyphenyl)maleimide 50g (0
．． 216 mol) was dissolved in ioog sulfuric acid at a temperature of 50° C. with thorough stirring. It took 45 minutes to completely dissolve.

Next, this was gradually poured into ice water consisting of 200 ml of ice and 100 ml of water to precipitate crystals of LN-(4-hydroxyphenyl)maleimide.

Next, when the crystals were dried from house to house, 25.8 g (0.
136 mol) of N-(4-hydroxyphenyl)maleimide was obtained.

The results of elemental analysis of the product clearly show that most of the acetoxy groups have been replaced with hydroxyl groups based on the theoretical values as shown below.

The yield was 63.0%. Example 2 N-(4-Fropionylphenyl)maleimito49. O
g (0.200 mol) in orthophosphoric acid at a temperature of 60°C.
Dissolve in g.

It took 60 minutes for it to completely dissolve. Next, this solution was gradually poured into ice water at 0°C to precipitate N-(4-hydroxyphenyl)maleimide, which was dried separately to yield 22.7g ( 0.120 mol) of yellow-orange crystals were obtained.

The melting point of this crystal was 188 to 189°C, and the presence of hydroxyl groups was confirmed from the infrared absorption spectrum, and it was found to be N-(4-hydroxyphenyl)maleimide.

Claims (1)

[Claims] 1 General formula (1) (wherein R represents a Cl to C7 alkyl group and a phenyl group, R' represents H, CH3, C2H5, F, CI, Br,
(2), and n represents an integer of 1 to 5. ) is hydrolyzed using a sulfur or phosphorus oxyacid under a temperature condition of 0 to 150°C. In, R' is HtCHs, C2Hs, F, CI, B
n represents an integer of 1 to 5; ) Production flow of N-(hydroxyphenyl)maleimide represented by