JPS5934703B2 - Process for producing 4-chloro-5-oxo-caproic acid-nitrile, 6-chloro-5-oxo-caproic acid-nitrile or mixtures thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to 4-chloro-5-oxocaproic acid mononitrile represented by the following formula, 6-chloro-5-oxocaproic acid mononitrile represented by the following formula, and mixtures thereof. However, these have not yet been described in the literature.

The object of the invention is thus to chlorinate a 20-40% aqueous solution of 5-oxocaproic acid mononitrile at a temperature of 25-55° C. and optionally isolate the respective chloro-keto-nitrile from the reaction mixture. Characterized by 4-chlororu 5-
This is a method for producing oxocaproic acid mononitrile, 6-chloro-5-oxocaproic acid mononitrile, or a mixture thereof. Hydrogen chloride liberated during chlorination is absorbed by water. It is surprising that the nitrile groups are not hydrolyzed in the process according to the invention, as would be expected in a reaction in an aqueous medium containing hydrogen chloride. The trifunctional compounds obtained according to the present invention, namely 4-
Chlor- and 6-chloro-5-oxocaproic acid mononitrile is an important starting material for the production of γ- or ε-amino acids, and also for the production of heterocycles in its nature as α-chloroketone. It is a synthetic ingredient.

The following method is particularly effective for the chlorination according to the invention: In the initial stage of the chlorination it is preferred to operate at temperatures of 25 DEG to 40 DEG C.

When the reaction has completely progressed and the initially yellow-green solution has discolored, the chlorination is carried out at a temperature of 40 to 55°C, preferably 40°C.
Continue further at ~45°C. In order to maintain this temperature level, external cooling is generally preferred. The amount of chlorine introduced for the reaction in this main reaction stage is about 2 to 3 times the amount in the initial stage of chlorination. The final stage of the chlorination reaction is indicated by a decrease in chlorine absorption and by the reappearance of the yellow coloration of the reaction solution. The turbidity of the solution, which is observed even in the first stage, indicates a phase separation of the water-insoluble chlorinated products, which prevents further chlorination of these products. The two chloro-keto-nitriles which can be prepared according to the invention can be isolated quite simply.

For example, after the chlorination has ended, the separated organic bottom phase is separated off, then washed with water and distilled without drying. Since the boiling points of both components are exactly 30°C apart, they can be easily separated. Example 1 A solution containing 5-oxocaproic acid-nitrile 3339 (3 mono(c)) in 1332 ml of water was placed in a 21-flask and stirred until the stoichiometrically required amount of chlorine was absorbed. Chlorine gas is introduced at 40-42°C.

After completion of chlorine absorption, stirring was continued for 1 hour, and the organic phase was separated.
Wash twice with 400 ml of water each time.

The reaction product was then distilled through a vacuum jacket column (length 100?, diameter 25 mm) packed with a Laschichi ring (ring diameter 4 m0) to give a concentration of 47.3% of the theoretical value at a boiling point of 90°C (1 mmH9). 4- of 205f! corresponding to the yield
Chlor-5-oxocaproic acid-nitrile and boiling point 1
959 of 6-chloro-5-oxocaproic acid, corresponding to a yield of 21.5% of theory at 18°C (1 mmH9).
A nitrile was isolated. Both new compounds are clear liquids with a density of 1.15.

As is clear from the above description, the objects of the present invention are as described in the claims, and embodiments thereof include the following. 2. A process as claimed in claim 1, which comprises separating off the oily second phase which separates out during the course of the reaction and subjecting it to distillation.

Claims (1)

[Claims] 1 20-40% of 5-oxo-caproic acid-nitrile
4-Chloro-5-oxo-caproic acid-nitrile, 6-, characterized in that the aqueous solution is reacted with chlorine at a temperature of 25-55 °C and optionally the respective chloro-keto-nitrile is isolated from the reaction mixture. Process for producing chloro-5-oxo-caproic acid-nitrile or mixtures thereof.