JPS582230B2 - Manufacturing method of azoguanyl compound - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an industrially advantageous method for producing intermediate iminoethers such as azoguanyl compounds and azo ester compounds, which are useful as polymerization initiators in the production of polymeric compounds.

Azoguanyl compounds are water-soluble, so their mineral salts are water-soluble.
This compound is particularly useful as a polymerization initiator in an aqueous solution.

Conventionally, this type of compound has been produced by reacting a corresponding azonitrile compound in an alcohol solvent in the presence of hydrochloric acid gas, and adding ammonia gas or an alkyl amine to the resulting imino ether, as described in U.S. Pat. No. 2,599,299. It was manufactured by.

However, in this method, when producing an azoguanyl compound intermediate imino ether from an azonitrile compound, the reaction proceeds rapidly, and the reaction cannot be controlled by cooling etc. even on a small experimental scale, and cannot be scaled up on an industrial scale. Manufacturing was extremely dangerous and completely impossible.

In order to suppress the reaction, attempts were made to add various catalysts, reduce the reaction solvent, and reduce the amount of hydrochloric acid gas, but no fully satisfactory results were obtained.

The present inventors have conducted intensive studies to find an industrially advantageous method for producing an azoguanyl compound that does not have the above-mentioned drawbacks, and have arrived at the present invention.

That is, the present invention adds alcohol to an azonitrile compound in the presence of hydrochloric acid gas, and when producing iminoether, the reaction is carried out in a solvent in which hydrochloric acid gas is less soluble, reducing the amount of alcohol and hydrochloric acid used. This is a method for producing an azoguanyl compound intermediate iminoether, which is characterized by the following.

The present invention focused on the fact that the reaction hardly progresses unless the amount of hydrochloric acid relative to alcohol is above a certain concentration, and the reaction progresses rapidly when the concentration exceeds a certain concentration. It is thought that this was achieved by reducing both the alcohol and hydrochloric acid, and by using a small amount of hydrogen chloride gas, the concentration of hydrogen chloride gas relative to the alcohol was kept above a certain level, and the solvent effect smoothed the reaction.

The azonitrile compound used in the present invention has the general formula (where R1 and R2 represent an alkyl, substituted alkyl, cycloalkyl, aralkyl, substituted aralkyl, aryl, or substituted aryl group).

It also means that R1 and R2 cooperate to form an aliphatic ring.

), such as 2,2'-azobis-isobutyronitrile, 2,2'-azobis-2-methylbutyronitrile, 2,2'-azobis-2,4-dimethylvaleronitrile, 2 -2'-Azobis-2-methylhexylonitrile, 2,2'-azobis-2-cyclopropylpropionitrile, 2,2'-azobis(2-phenylpropionitrile), and the like.

Solvents with low solubility of hydrochloric acid gas used in the present invention include, for example, hexane, octane, decane, cyclohexane, methylcyclohexane, bicyclohexyl, benzene, toluene, xylene, amylbenzene, tetralin, decalin, ethylbenzene, trimethyl benzene,
Cumene, petroleum ether, kerosene, turpentine oil, aliphatic and aromatic hydrocarbons such as dipentene, tetrahydrofuran,
Ethers such as ethyl ether, chloroform, halogenated hydrocarbons such as carbon tetrachloride, methyl ethyl ketone,
These include ketones such as methyl isobutyl ketone, and esters such as methyl acetate and ethyl acetate.

As the alcohol, ordinary alcohols can be used without any problem, but in order to obtain the desired product in high yield, it is preferable to use alcohols with lower alkyl groups such as methyl alcohol, ethyl alcohol, inpropyl alcohol, and butyl alcohol.

As for the amount of alcohol used, it is sufficient to use the theoretical amount or twice the theoretical amount.

The amount of hydrochloric acid gas to be used varies slightly depending on the type and amount of the solvent in which hydrochloric acid gas is poorly soluble, but it is preferably a theoretical amount or about twice the theoretical amount.

The introduction temperature of hydrochloric acid gas varies slightly depending on the alcohol and the type of solvent that does not dissolve hydrogen chloride gas, etc.
Due to the need to increase the alcohol concentration to approximately 30% or more,
It is preferable to carry out the reaction at a temperature of approximately 15°C or lower.

Since the iminoether product thus produced precipitates from the reaction mixture, it can be easily isolated from the reaction mixture by cooling and filtering.

In order to produce the corresponding azoguanyl compound from the iminoether compound, the azoguanyl compound can be produced by isolation, or by directly adding ammonia, aliphatic/aromatic amines, etc. to the reaction mixture without isolation.

As mentioned above, the method of the present invention does not cause a rapid reaction,
This is an industrially extremely useful method for producing iminoether of an azoguanyl compound intermediate, which has the advantages of being extremely easy to control the reaction, requiring only a theoretical amount of hydrochloric acid gas, and being economical.

Examples are given below to further explain the present invention.

In the examples, parts expressed are parts by weight.

Example 1 57 parts of azobisisobutyronitrile, 25 parts of methanol and 200 parts of toluene are mixed and cooled.

29 parts of hydrochloric acid gas is introduced at 10° C. or lower over a period of 5 hours.

After the introduction, the reaction is continued for an additional 4 hours at a liquid temperature of 20°C.

After cooling, 115 parts of 2,2'-azobis(1-imino-l-methoxy-2-methylpropane) hydrochloride were obtained.

The melting point was 125°C. Comparative Example 1 When a similar reaction was carried out using 225 parts of methanol instead of 25 parts of methanol and 200 parts of toluene in Example 1, the desired product was not obtained at all and only the raw material was recovered.

Comparative Example 2 When the same reaction was carried out using 225 parts of methanol instead of 25 parts of methanol and 200 parts of toluene in Example 1 and increasing the amount of hydrochloric acid gas to 117 parts, a rapid reaction occurred during the process. A large amount of ice water was used to suppress the heat generation, but the temperature could not be controlled.

After the reaction was completed, 94 parts of the target product were obtained in the same manner.

However, the melting point was slightly lower at 115-120°C.

Incidentally, scale-up using this method is considered impossible because temperature control is not possible.

Example 2 22 parts of ethanol and 200 parts of n-hexane were mixed with 50 parts of 2,2'-azobis-2,4-dimethylvaleronitrile and cooled.

17 parts of hydrochloric acid gas are introduced over 3 hours at 5-15°C.

After introduction, react at 20-25°C for 3 hours, add 80 parts of water,
After neutralization and separation, the mixture was concentrated to obtain 45 parts of a pale yellow oil.

The half-life at 60°C was 7.13 x 103 sec, and the decomposition rate constant was 0.9 x 10-4 sec-1.

Comparative Example 3 22 parts of ethanol and 20 parts of n-hexane in Example 2
When a similar reaction was carried out using 222 parts of ethanol instead of 0 parts, the target product was not obtained at all, and only the raw material was recovered.

Example 3 19 parts of 2,2'-azobis-2-cyclopropylpropionitrile were mixed with 10 parts of methanol and 70 parts of cyclohexane and cooled.

10 parts of hydrochloric acid gas are introduced at 5-10°C.

After reacting at room temperature for 3 hours, it was collected by filtration and 2,2'-azobis(1-imino-1-methoxy-2-cyclopropylpropane) 4
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Example 4 2,2'-azobis-2-methylhexanenitrile 21
13 parts of methanol and 90 parts of chloroform are mixed and cooled.

9 parts of hydrochloric acid gas are introduced at 5-10°C.

After reacting at room temperature for 5 hours, the reaction mixture was collected by filtration to obtain 43 parts of 2,2'-azobis-1-imino-1-methoxy-2-methylpentane.

Claims (1)

[Claims] 1. When producing an iminoether by reacting a compound of the general formula (wherein Rl and R2 represent an alkyl or cycloalkyl group) with alcohol in the presence of hydrochloric acid gas, the solubility of the hydrochloric acid gas A method for producing a compound of the formula (in the formula, R1 and R2 are the same as above; R3 represents an alkyl group), characterized by carrying out the reaction in a solvent with a small amount of