JPH082848B2 - Process for producing 4-nitrosodiphenylamines - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention is directed to the nitrosation of diphenylamines to
-A method for producing nitrosodiphenylamines.

The 4-nitrosodiphenylamines obtained by the present invention are important compounds as intermediates for rubber antiaging agents, azo dyes and the like.

<Prior Art> As a method for producing 4-nitrosodiphenylamine from diphenylamine, diphenylamine is N-nitrosated with a nitrosating agent such as nitrite in an aqueous solvent to isolate N-nitrosodiphenylamine, or an organic solvent is used. After separating and extracting with Fische, by adding alcohol and hydrogen chloride under new anhydrous condition, Fische
A method of carrying out r-Hepp rearrangement to obtain the desired product has been generally known (Japanese Patent Publication No. 60-42232, USP 3,728,392, etc.).

On the other hand, in order to obtain the desired product directly from diphenylamine without the need for isolation or extraction separation of N-nitrosodiphenylamine, N-nitrosation and rearrangement can be performed with an alcohol solvent whose water content is as low as possible. A one-step method has been proposed which is carried out simultaneously.

The one-step method involves adding an alcohol solution of hydrogen chloride to a mixture of aromatic solvent containing slightly water, nitrite such as sodium nitrite, and diphenylamine (USP 4,362,893), and also including aromatic solvent. There is known a method of reacting diphenylamine with alkyl nitrite and anhydrous hydrogen chloride in a substantially anhydrous fatty acid alcohol solvent having 5 to 10 carbon atoms (Japanese Patent Publication No. 60-42233).

<Problems to be Solved by the Invention> The above-described one-step method is excellent in that 4-nitrosodiphenylamine is obtained in good yield, but is not necessarily satisfactory for industrial implementation. Ie US
In the method according to P.4,362,893, since nitrite is used in the presence of a small amount of water, the inorganic salt such as nitrite is always in a slurry state with poor dispersibility, and the nitrosating agent is forced to undergo a solid-liquid reaction. . In addition, since it is necessary to control a very small amount of water within a certain range in a two-component solvent system, it is necessary to adjust the water content when the solvent is recovered and reused. On the other hand, in the method according to Japanese Patent Publication No. 60-42233, alkyl nitrite used as a nitrosating agent is
Due to its explosiveness and dispersibility and not easy to store and store, industrial implementation involves various difficulties.

The object of the present invention is to nitrosate diphenylamine to produce 4-nitrosodiphenylamine,
To provide a highly practical one-step method free from reaction conditions such as solid-liquid reaction and adjustment of water content and operational restrictions, and having no problem in handling again by using a nitrosating agent. is there.

<Means for Solving the Problems> Among the various nitrosating agents, the inventors of the present invention have selected ones that are homogeneous in an organic solvent and do not require the presence of water at the time of nitrosation, and are not explosive or decomposable. ,
As a result of intensive studies, they have found that nitrosyl chloride is an excellent nitrosating agent that satisfies the above-mentioned object, and have reached the present invention. That is, the present invention has the general formula (I) (In the formula, R ¹ and R ² are each a hydrogen atom, a methyl group, an ethyl group,
It represents a group selected from the group consisting of a cyclohexyl group, a methoxy group, an ethoxy group, a chlorine atom and a bromine atom. ) The diphenylamines represented by the formula (II) are reacted with nitrosyl chloride and hydrogen chloride in a solvent containing an alkyl alcohol having 1 to 10 carbon atoms or a cycloalkyl alcohol. (In the formula, R ¹ and R ² have the same meanings as described above.) A method for producing 4-nitrosodiphenylamines.

 Hereinafter, the configuration of the present invention will be described in detail.

The diphenylamines used in the present invention are compounds represented by the above formula (I), and specific examples include:
For example, diphenylamine, 4-methyldiphenylamine, 4-ethyldiphenylamine, 2-cyclohexyldiphenylamine, 4-cyclohexyldiphenylamine, 2-methoxydiphenylamine, 3-methoxydiphenylamine, 4-methoxydiphenylamine, 4-
Examples thereof include ethoxydiphenylamine, 4-chlorodiphenylamine, 4-bromodiphenylamine and the like. Preferred are diphenylamine, 4-cyclohexylamine, 3-methoxydiphenylamine, 4-methoxydiphenylamine and the like.

In the present invention, a solvent containing an alkyl alcohol having 1 to 10 carbon atoms or a cycloalkyl alcohol is used. Specific examples of such alcohols include methanol, ethanol, propanol, isopropanol, butanol, isobutanol, secondary butanol, tertiary butanol, pentanol, hexanol, cyclohexanol, heptanol, octanol, 2-ethylhexanol and the like. To be Preferably, an alkyl alcohol having 4 to 8 carbon atoms is used, and specific examples thereof include butanol, isobutanol, hexanol, heptanol, octanol, 2-ethylhexanol and the like. It is also possible to use a mixture of the above-mentioned several alcohols, or to use a solvent such as toluene or chloroform that does not react under the nitrosation and rearrangement reaction conditions and the above-mentioned alcohol in a range that does not impair the effects of the present invention. . Although the amount of the solvent used is arbitrary, it is usually 1 to 20 times by weight that of the diphenylamines. The nitrosyl chloride used in the present invention is usually not explosive or dispersible, and is a gas (boiling point −5.5 ° C.) that is easy to handle if attention is paid to corrosiveness. Therefore, it can be stored in a corrosion-resistant pressure-resistant container or the like, and the required amount can be used at any time. Also, just by blowing hydrogen chloride gas into nitrosyl sulfuric acid,
Since it can be quantitatively generated as a gas, it is also possible to use it for the reaction while installing a nitrosyl chloride generator and controlling the generation amount by the amount of hydrogen chloride gas blown. The sulfuric acid by-produced in this case can be reused for the production of nitrosyl sulfuric acid. The amount of nitrosyl chloride used is usually 0.90 to 2.0 times the molar amount of diphenylamine. The molar ratio is preferably 0.95 to 1.2.

Hydrogen chloride used in the present invention may be directly introduced as a gas into the reaction mixture, or may be charged after being dissolved in the solvent used in the reaction. It is also possible to premix with the starting material diphenylamine and prepare as the hydrochloride. Regarding the amount of hydrogen chloride used, nitrosyl chloride reacts,
Since an equimolar amount of hydrogen chloride is produced, and this is also used in the reaction, the amount thereof may be smaller than that in the conventional method, and is usually 0.5 to 3 times mol, preferably 0.7 mol, relative to diphenylamines.
It is about 1.5 times mol.

The reaction temperature in the present invention is usually 5 to 60 ° C, preferably 10 to 40 ° C.

The reaction pressure in the present invention may be either normal pressure or increased pressure, but sufficient results can be obtained at normal pressure.

The reaction time in the present invention varies depending on the amounts of nitrosyl chloride and hydrogen chloride used for the diphenylamines, the reaction temperature, etc., but is usually 0.5 to 3 hours in total for the addition of nitrosyl chloride and hydrogen chloride, and 0.5 to 3 for the completion of the reaction. It takes 6 hours.

The reaction method in the present invention is arbitrary. For example, a solvent containing an alkyl or cycloalkyl alcohol is charged with diphenylamines, and while maintaining a predetermined temperature, a predetermined amount of nitrosyl chloride is blown into the reaction mixture through a gas introduction tube, and then hydrogen chloride gas is similarly added. Blow. Alternatively, nitrosyl chloride and hydrogen chloride may be blown in at the same time. After the blowing is over,
The temperature is maintained and stirring is continued in order to complete the reaction.

Various methods are possible for the isolation operation. For example, after the completion of the reaction, if the hydrochloride of p-nitrosodiphenylamine is in the form of slurry, pass it as it is,
The desired product can be obtained as a hydrochloride, or can be obtained by freezing 4-nitrosidiphenylamine by crystallization or the like after neutralization with an alkaline aqueous solution according to a conventional method. In some cases, the desired product can be used as a raw material for a rubber anti-aging agent such as N-alkyl-N'-phenyl-p-phenylenediamine without being isolated as a slurry or solution.

<Examples> Hereinafter, the present invention will be described in more detail with reference to Examples.

Example 1 8.46 g (50.0 mmol) of diphenylamine was added to 40 ml of isobutanol, and 3.21 g (49.0 mmol) of nitrosyl chloride gas was introduced from a glass cylinder into the reaction mixture through a gas introduction tube while maintaining the temperature at about 20 ° C. and stirring. It took a while to blow. Then, at the same temperature, hydrogen chloride gas 1.40 g (38.4 mmol)
Was blown in the same manner for about 30 minutes. The reaction was continued at 20-30 ° C for about 4 hours. The reaction mixture changed from a red slurry to a red brick colored slurry.

The slurry was filtered, washed twice with hexane, and dried under reduced pressure to obtain 10.63 g (45.3 mmol, yield 91%) of 4-nitrosodiphenylamine hydrochloride as a red brick-colored powder.

Example 2 8.46 g (50.0 mmol) of diphenylamine was added to 10 ml of toluene.
And mixed with 40 ml of hexanol, and kept at 20 to 25 ℃ with stirring, 3.26 g of nitrosyl chloride gas (50.0 m
Mol) was blown into the reaction mixture from a glass bomb through a gas inlet tube for about 1 hour. Then, at the same temperature, 2.28 g (62.5 mmol) of hydrogen chloride gas was similarly blown in over about 1 hour. The reaction was continued at 25-35 ° C for about 2.5 hours.

An aqueous sodium hydroxide solution was added to the resulting red brick colored slurry to neutralize it, and after heating and dissolution, the mixture was cooled to 4
Crystals of nitrosodiphenylamine were precipitated. The crystals are filtered and washed twice with hexane to give the desired crystals, 9.30 g
(47.0 mmol, yield 94%) was obtained.

Example 3 The reaction was carried out in the same manner as in Example 2 except that 9.96 g (50.0 mmol) of 4-methoxydiphenylamine was added to the solvent of 40 ml of hexanol.

Isolation and purification were carried out in the same manner as in Example 1 to obtain 10.84 g of 4-methoxy-4'-nitrosodiphenylamine hydrochloride (4
0.9 mmol, yield 82%) was obtained.

<Effects of the Invention> According to the present invention, in producing 4-nitrosodiphenylamine by nitrosating diphenylamines, the objective N-nitrosodiphenylamine, which is an intermediate, is not directly isolated or extracted and separated by a one-step operation. You can get things. In addition, since nitrosyl chloride used as a nitrosating agent is soluble in an organic solvent and does not require the presence of water during nitrosation, there are almost no restrictions on reaction conditions and operations. Moreover, nitrosyl chloride is not explosive or decomposable, and there are almost no handling problems.

Furthermore, since hydrogen chloride produced from nitrosyl chloride can be effectively used as it is for the reaction, a small amount of hydrogen chloride needs to be supplied.

Therefore, the present invention is a highly practical method capable of easily producing 4-nitrosodiphenylamine from diphenylamine in a single step.

Claims (1)

[Claims] 1. A general formula (I) (In the formula, R ¹ and R ² are each a hydrogen atom, a methyl group, an ethyl group,
It represents a group selected from the group consisting of a cyclohexyl group, a methoxy group, an ethoxy group, a chlorine atom and a bromine atom. ) The diphenylamines represented by the formula (II) are reacted with nitrosyl chloride and hydrogen chloride in a solvent containing an alkyl alcohol having 1 to 10 carbon atoms or a cycloalkyl alcohol. (In the formula, R ¹ and R ² have the same meanings as described above.) A method for producing 4-nitrosodiphenylamines.