DE1123330B - Process for the preparation of 3,3-dialkyl-diazacyclopropanes - Google Patents

Description

Process for the preparation of 3,3-dialkyldiazacyclopropanes Derivatives of diazacyclopropane have hitherto only been prepared by the action of diazo compounds on azo compounds according to the following reaction equation Here, R and R denote, for example, a carbethoxy or phenyl group, while R2 can represent a hydrogen atom, an alkyl or a phenyl group and R3 can represent an alkyl or phenyl group.

Carrying out this process and making the required Starting materials is difficult. Compounds in which R and R represent hydrogen atoms, cannot be produced by this process.

A series of compounds whose structure used to be with a CNN three-membered ring As the hydrazones and diazo compounds, are formulated according to the present day State of research definitely no diazacyclopropanes.

It has now been found that 3,3-dialkyldiazacyclopropanes of the general formula wherein R 1 and R 2 represent alkyl groups can be prepared in a surprisingly simple manner and with very good yields by a carbonyl compound of the general formula in a batchwise or continuous procedure treated in the liquid state at a temperature between -50 and -t- 100'C and optionally under pressure with ammonia and chlorine, ammonia and chlorine being used in a volume ratio between 4: 1 and 50: 1. The diazacyclopropane derivative formed in this way accumulates in the carbonyl compound. The reaction can be represented by the following equation: In the simplest embodiment of the process according to the invention, the gases chlorine and ammonia are introduced into the ketone with vigorous stirring. If the gases are brought together before they are introduced, a mixture of chloramine and ammonia is initially formed. The diazacyclopropane derivatives can consequently be produced with the same success in the process according to the invention by the action of chloramine and ammonia on the ketones.

The process products can be obtained in pure form from the reaction mixture by distillation, extraction or crystallization. The concentration of the diazacyclopropane derivatives in the carbonyl compound is generally so high that isolation of the diazacyclopropane derivatives is often unnecessary in the event of further processing and the subsequent conversion of the diazacyclopropane derivatives can be carried out directly in the respective solution. Temperatures between -20 and + 20 ° C. are particularly suitable as reaction temperatures. The volume ratio of ammonia to chlorine is at most 50: 1; a volume ratio of 15: 1 is already sufficient; a volume ratio of 6: 1 should generally not be undershot.

There are several options for carrying out the process to disposal. The reaction components can be used in pure form or the gases ammonia and chlorine after dilution with a Inert gas.

You can convert chlorine and ammonia from above in a closed Introduce a container in which the carbonyl compound is intensively stirred. By Overpressure accelerates the course of the reaction. It is therefore of Advantage of letting the gases act on the carbonyl compound under pressure.

On the other hand, you can get the carbonyl compound from above through a reaction tower conduct and feed chlorine and ammonia from below towards the carbonyl compound. Around To largely avoid losses of reaction products, it is advisable to to apply the pre-cooled carbonyl compound to the reaction tower or with it To provide cooling elements and to cool the reaction mixture in the reaction tower. Instead of in countercurrent, the reaction components can also be used in cocurrent in a cooled Merge pipe. In this case, it is appropriate to carry out the reaction in a reaction vessel to finish.

The process can be designed continuously by one Reaction container continuously removed solution and fresh starting solution in the appropriate Amount is supplied. The removed solution can be in unsatisfactory conversion Circulation and again the action of chlorine and ammonia, if necessary with the addition of nitrogen, until an optimal implementation or Enrichment is achieved. The gas escaping from the reaction vessels, the consists essentially of ammonia, optionally mixed with nitrogen, can be used again for the reaction immediately or after the nitrogen has been removed will.

The diazacyclopropane derivatives obtainable according to the invention are thermal unstable and break down into gaseous products at higher temperatures. The decomposition temperature depends on the nature of the substituents R1 and Ra and is approximately in the range of 50 up to 200 ° C. Due to this property, the process products are particularly suitable as a blowing agent in the production of foams. They can also be saved as Antioxidant to avoid undesired polymerization of starting materials for Plastics or paints are used. Also to stabilize fuels and the diazacyclopropanes can be used as anti-knock agents.

Example 1 In a closed reaction vessel are in 600 parts by weight Butanone, which were cooled to -5'C, with good stirring per hour 85 parts by weight Introduced ammonia and 19.3 parts by weight of chlorine. The chlorine was by 25 parts by weight Diluted nitrogen. The reaction is terminated after 2 hours. It have 47 parts by weight of 3-methyl-3-ethyl-diazacyclopropane formed. After distilling off unreacted butanone in vacuo at 30 ° C and distilling the residue 32 parts by weight of pure product are obtained; Bp 15. 34 to 35 ° C; n2 ° = 1.4388; F. 18.6 ° C.

Elemental analysis: Calculated ... C 55.77 ° / o, H 11.70 ° / o, N 32.53 ° / o; found ... C 54.70%, H 11.62%, N 31.66%.

Example 2 Butanone is sprayed into a reaction tower from above. The draining butanone is circulated via a sedimentation vessel and a pump returned to the reaction tower. All of the butanone (200 parts by weight) becomes twenty times pumped around in the hour.

Ammonia is first passed through the reaction tower. Once the If the reaction tower is free of air, the reaction tower is closed off from the outside an ammonia overpressure of 200 mm Hg was set. In the lower third of the tower 32.7 parts by weight of chlorine are injected per hour. By pre-cooling the butanone a reaction temperature of -2 to + 4 ° C is maintained. The ones at the foot collecting reaction solution is returned to the reaction tower. After 30 minutes the reaction is canceled. There are 15.8 parts by weight of 3-methyl-3-ethyl-diazacyclopropane (77.70 /, the theory) emerged.

Example 3 In a vertical pipe there are 83 parts by weight from above Ammonia and 14 parts by weight of chlorine introduced per hour. The chlorine stream is in front the meeting with ammonia is diluted with 89 parts by weight of nitrogen. In 3-pentanone circulated from above is also introduced into the tube. the Reaction components emerging from the tube are placed in a stirred vessel for post-reaction out, which is kept at -10 to -5 ° C. The excess gas (ammonia and Nitrogen) presses the liquid phase through a siphon into a second container, in which gas and liquid separate. The liquid is used to remove the precipitated ammonium chloride pressed through a filter and then into the reaction tube returned. In this way, 900 parts by weight of 3-pentanone are used eleven times per hour pumped over. The ammonia-containing exhaust gas is also circulated into the reaction tube returned. The reaction is ended after 4 hours. 73 parts by weight are obtained 3,3-diethyl-diazacyclopropane (91.2% of theory). After distilling off the excess ketone crystallized at 30 ° C in vacuo and cooling the residue the diazacyclopropane from. After purification by recrystallization from acetone 61 parts by weight of 3,3-diethyl-diazacyclopropane are obtained; F. 53 ° C.

Elemental analysis calculated ... C 59.95%, H 12; 07 ° / o, N 27.98%; Found ... C 59.20%, H 12.02 ° / o, N 28.07 ° / o. Example 4 In a closed reaction vessel with stirrer, in which 1600 parts by weight of acetone are located through a tube that extends to the bottom of the reaction vessel, at 45 ° C per hour together 152 parts by weight of ammonia and 68 parts by weight of chlorine initiated. The reaction solution is also about ten times in through this tube pumped around the hour. The temperature is increased by additional heating during the kept at 45 ° C throughout the reaction. The excess ammonia leaves the apparatus through a reflux condenser and is then continued in condensation vessels cooled down. The condensate is returned to the reaction vessel. After 2 hours the implementation is terminated. 81.5 parts by weight of 3,3-dimethyldiazacyclopropane are obtained (58% of theory).

EXAMPLE 5 In a closed reaction vessel, together 152 parts by weight of ammonia and 68 parts by weight of chlorine are introduced into 1500 parts by weight of 3-pentanone with thorough stirring at 75 ° C. per hour. The reaction solution is pumped around ten times an hour, the reaction temperature being kept at 75 ° C. for the entire duration of the reaction. The reaction is terminated after 2 hours. 99.5 parts by weight of 3,3-diethyldiazacyclopropane were formed.

Claims (3)

PATENT CLAIMS: 1. Process for the preparation of 3,3-dialkyldiazacyclopropanes of the general formula in which R1 and R2 represent alkyl groups, characterized in that a carbonyl compound of the general formula is used in a batchwise or continuous procedure treated in the liquid state at a temperature between -50 and -r-100 ° C and optionally under pressure with ammonia and chlorine, ammonia and chlorine being used in a volume ratio between 4: 1 and 50: 1. 2. Procedure according to claim 1, characterized in that instead of chlorine and ammonia a mixture of chloramine and ammonia is used. 3. The method according to claim 1 and 2, characterized in that the reaction is carried out in the presence of an inert gas will.