JPH01275550A - Production of adamantane isocyanate - Google Patents

Abstract

PURPOSE:To obtain the title compound useful as a raw material for polyurethane safely in high purity and in high yield, by reacting an alkali metallic salt of admantane carboxylic acid, a raw material having low toxicity, with a phosphoryl azide compound in a polar solvent. CONSTITUTION:An alkali metallic salt of admantane carboxylic acid shown by formula I (Ad is adamantane; M is alkaline metal such as lithium, sodium or potassium; n is 0 or 1-3; m is 1-4) as a raw material is reacted with a phosphoryl azide shown by formula II (R is lower alkyl, aryl or aralkyl) by using m-1, 1m (m is m in the formula I) compound shown by formula II based on 1mol compound shown by formula I in a polar solvent such as dimethylformamide at 80-120 deg.C preferably 100-150 deg.C to give the aimed compound. The concentration of the alkaline earth salt of the alkaline metallic salt of damantanecarboxylic acids is preferably 0.2-0.5 normal.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for producing adamantane isocyanates from an alkali metal salt of adamantane carboxylic acids and a phosphoryl azide compound.

[Prior Art] Conventionally, as a method for producing adamantane isocyanate, there has been a method for producing adamantane isocyanate from adamantane carboxylic acid via adamantane carboxylic acid azide (U.S. Pat. No. 3,301,827, Chemical Abstracts). Vol. 80, p. 394 (1974)), a method for reacting adamantylamine hydrochloride with phosgene (Zh, V
es.

Khim, 0-ray Vol. 24 No. 1, page 95 (19
1975)) and a method of reacting bromoadamantane with cyanate (Japanese Patent Application Laid-open No. 88060/1983) are known.

However, since all of these methods use highly toxic raw materials, there are safety issues.

On the other hand, conventional methods for producing adamantane isocyanate using raw materials with low toxicity include a method in which diphenylphosphoryl azide is reacted with 1,3-adamantane dicarboxylic acid in the presence of a trialkylamine (Japanese Patent Publication No. 57
-15828) is known.

However, the 1,3-diisocyanatoadamancune obtained by this method has the disadvantage that it is colored pale yellow and has an unpleasant odor due to the contamination of the by-produced phosphoric acid-trialkylamine complex. Furthermore, since the phosphoric acid-trialkylamine complex exists in a large amount in the form of a viscous liquid, it is difficult to separate 1,3-diisocyanatoadamantane by vacuum distillation, making purification difficult, and furthermore, the isolation yield is low. There was a drawback that it could not exceed 95%.

[Problems to be Solved by the Invention] An object of the present invention is to provide a method for producing adamantane isocyanates with high purity and high yield using raw materials with low toxicity.

[Means for Solving the Problems] Therefore, in order to achieve the above-mentioned problems, the inventors of the present invention have conducted extensive research and found that, by using an alkali metal salt of adamantane carboxylic acid instead of adamantane carboxylic acid, phosphoryl It was discovered that by reacting with an azide compound, the by-product was converted into a phosphate ester alkali metal salt, which could be easily separated and purified in a post-processing step, leading to the completion of the present invention.

That is, the present invention is a method for producing adamantane isocyanates, which is characterized by reacting an alkali metal salt of an adamancune carboxylic acid with a phosphoryl azide compound in a polar solvent.

The adamancune carboxylic acids used as raw materials in the present invention have the general formula (1) % formula %] (where Ad is adamancune, M is lithium,
It is an alkali metal such as sodium or potassium, n is 0 or an integer of 1 to 3, and m is an integer of 1 to 4. ) and compounds having substituents that do not inhibit the reaction. Examples of substituents that do not inhibit the reaction include lower alkyl groups, aryl groups,
Examples include an aralkyl group, an alkylaryl group, and a lower alkoxy group. Examples of lower alkyl groups include t; for example, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, and tert-butyl group; examples of aryl groups include t; There are phenyl groups, diphenyl groups, naphthyl groups, etc., and aralkyl groups include, for example, benzyl groups, phenylethyl groups, 1-7 enylpropyl groups, 2-phenylpropyl groups, 3-phenylpropyl groups, 1.1-methyl There are phenylethyl groups, 1,2-ethylphenylethyl groups, etc., and alkylaryl groups include, for example, methylphenyl groups, dimethylphenyl groups, trimethylphenyl groups,
Examples include ethylphenyl group, diethylphenyl group, triethylphenyl group, methylethylphenyl group, n-butylphenyl group, tert-butylphenyl group, amyl phenyl group, cyclohexylphenyl group, cresyl group, etc.
Examples of lower alkoxy groups include methoxy, ethoxy, propoxy, and butoxy groups. Among these substituents, lower alkyl groups are preferred, with methyl and ethyl groups being particularly preferred. These compounds may be used alone or in combination of two or more.

In the present invention, the phosphoryl azide compound used as the other raw material is a compound represented by the general formula (2)% formula% (wherein R refers to a lower alkyl group, an aryl group, an aralkyl group, etc.). be. The substituents for lower alkyl groups, aryl groups, and aralkyl carboxylic acids are the same as those described above, and among these substituents, aryl groups are preferred, and phenyl groups are particularly preferred. These compounds may be used alone or in combination of two or more.

The ratio of adamantane carboxylic acids and phosphoryl azide compounds to 1 mole of adamantane carboxylic acids is
The amount of phosphoryl azide compound is m to 1.2 mmol, preferably m to 1.1 mmol.

Here, m is m in general formula (1).

In the present invention, the adamantane carboxylic acids and the phosphoryl azide compound are reacted in a polar solvent. This polar solvent is not particularly limited as long as it does not react with the raw materials or products and is not decomposed by the raw materials or products, preferably one with a boiling point of 80'C or higher. good. Examples of such polar solvents include dimethylformamide, N,N-dimethylacetamide,
Amides such as N-methylpyrrolidone, sulfoxides such as hexamethylphosphoamide and dimethyl sulfoxide, nitro compounds such as nitromethane and nitrobenzene, nitriles such as tetramethylurea, acetonitrile, propionitrile, benidinitrile, methyl ethyl ketone, methyl isobutyl ketone Examples include ketones such as

These polar solvents may be used alone or in combination of two or more.

Note that a non-polar solvent may be mixed with the polar solvent. The mixing ratio of the nonpolar solvent is preferably up to 70% by volume. If it exceeds 70% by volume, the alkali metal salt of adamantane carboxylic acids becomes difficult to dissolve, and the reaction may not proceed. Examples of nonpolar solvents include aromatic hydrocarbons such as benzene, toluene, and xylene, and aliphatic hydrocarbons such as hexane, heptane, and octane.

The concentration of the alkali metal salt of adamantane carboxylic acids in the polar solvent is usually 0.1 to 1.0 normal, preferably 0.2 to 0.5 normal.

In the present invention, the alkali metal salt of the adamantane carboxylic acid and the phosphoryl azide compound are reacted in a polar solvent. Reaction conditions vary depending on the types of raw materials and solvents and are not particularly limited. The reaction temperature is usually in the range of 80 to 200°C, preferably in the range of 100 to 150°C. The reaction temperature is 200
If the reaction temperature exceeds 80°C, the phosphoryl azide compound may decompose, and if the reaction temperature falls below 80°C, the reaction may not proceed. The reaction pressure is usually carried out at normal pressure, but it can also be carried out under increased pressure.

The reaction time is usually 0.5 hours or more, preferably 1 hour or more. If the reaction time is less than 0.5 hours, the reaction may not be completed.

Incidentally, the alkali metal salt of adamantane carboxylic acids and the phosphoryl azide compound as raw materials may be mixed in their entire amounts from the beginning of the reaction, but it is preferable to add the phosphoryl azide compound dropwise during the reaction.

Since the reaction of the present invention generates nitrogen, if the entire amount is mixed from the beginning of the reaction, nitrogen may be generated all at once.

The phosphoryl azide compound may be added as is, or may be added after being dissolved in the polar solvent.

Further, the reaction of the present invention is preferably carried out under stirring.

In the present invention, the desired product, adamantane isocyanate, can be produced by the reaction described above. Adamantane isocyanates refer to adamantane carboxylic acids as raw materials in which at least one carboxyl group is converted to an incyanate group.

In the present invention, from the reaction mixture obtained by the above reaction, the target product adamancune isocyanate and the by-product general formula (3) % formula %) (where R and M are the same as above) ) can be easily separated. This separation can be performed by various known methods, such as filtration, decantation, etc., but by adding a nonpolar solvent to the reaction mixture,
It is preferable to promote precipitation of the phosphate ester alkali metal salt before filtration.

The separated adamantane isocyanates can be purified by known methods, such as distillation, column chromatography, extraction, etc., but vacuum distillation is preferred because of its simple operation. The temperature of vacuum distillation varies depending on the type of adamantane isocyanate and the degree of vacuum, but is usually in the range of 80 to 300°C, preferably in the range of 100 to 200°C.

If the temperature is high, polymers of adamanthine isocyanates may be formed. The degree of reduced pressure is usually 10-0.01
mm [range of 19].

[Examples] Next, the present invention will be specifically explained with reference to Examples, but the present invention is not limited to these Examples in any way.

Example 1 (Preparation of sodium salt of 1,3-adamantanedicarboxylic acid) 8,00y 1,3-diadamantane dicarboxylic acid synthesized according to the method described in U.S. Pat. No. 3,356,718. The acid was dissolved in 18 mM of 4N aqueous sodium hydroxide solution, and the solution was dissolved at 90% under reduced pressure of 10 Torr.
It was concentrated and dried at 100°C for 2 days and then for 1 day to obtain a white powder solid of the sodium salt of 1,3-adamantanedicarboxylic acid.

(Production of 1,3-diisocyanatoadamantane) Sodium salt of 1,3-adamantanedicarboxylic acid prepared 4
．． 569 was stirred and suspended in 40 mL of N,N-dimethylacetamide and heated to 110°C under an argon atmosphere. Then, 10 m of N,N-dimethylacetamide
(diphenylphosphoryl azide dissolved in 1 9.369
was added dropwise over 0.5 hours, and after completion of the addition, the reaction was completed at 110° C. for 1 hour. After cooling the reaction mixture, 100 ml of toluene was added to precipitate the by-product sodium diphenyl phosphate, which was removed by filtration and the filtrate was concentrated.

The concentrated liquid was distilled under reduced pressure using a Kugelrohr to obtain colorless and odorless 1,3-diisocyanatoadamancune 3.669 (
A purity of 99% and a yield of 98% were obtained.

The physical properties of the obtained 1,3-diisocyanatoadamancune are shown below.

Boiling point: 110-115°C (0, ITorr) Phosphorus content: o, lppm or less IR: vNco 2250 cm-'Example 2 As a solvent, N,N-dimethylacetamide in Example 1 was replaced with N,N- The procedure was carried out in the same manner as in Example 1, except that a mixture of dimethylacetamide and toluene (a mixture of 30% by volume of N,N-dimethylacetamide and toluene) was used.

As a result, 1,3-diisocyanatoadamantane 3.3
69 (purity 99%, yield 96%) was obtained.

The phosphorus content of this 1,3-diisocyanatoadamancune is 0. It was less than lppm.

Comparative Example 1 The same procedure as in Example 1 was performed except that toluene was used in place of N,N-dimethylacetamide in Example 1 as the solvent. However, in this case the reaction did not proceed at all.

Comparative Example 2 1,3-adamantanedicarboxylic acid g,o09 prepared in Example 1 and 7.309 g of triethylamine were stirred and suspended in 80 mQ of toluene and heated to 110°C under an argon atmosphere. Next, diphenylphosphoryl azide 209 dissolved in 20 mft of toluene was added dropwise over 1 hour, and the reaction was completed 110° after the completion of the dropwise addition.

The reaction solution was concentrated, and the concentrated solution was then distilled under reduced pressure using a Kugelrohr to obtain 7.31 g of a compound consistent with Example 1 (purity 98%, yield 93%). However, this compound was colored pale yellow and had a strange odor. Then,
This compound was distilled under reduced pressure again, but the off-flavor remained. The phosphorus content at this time was 15 ppm.

[Effects of the Invention] As explained above, according to the present invention, colorless and odor-free highly purified adamantane isocyanates can be safely produced in high yield by reacting adamantane carboxylic acids and phosphoryl azide compounds. I can do it.

Therefore, the present invention is an industrially extremely useful method for producing adamantane isocyanates.

The adamantane isocyanates obtained by the present invention can be used as raw materials for polyurethane.

Claims (1)

[Claims] 1. A method for producing adamantane isocyanates, which comprises reacting an alkali metal salt of adamantane carboxylic acids with a phosphoryl azide compound in a polar solvent.