DE1170960B - Continuous process for the production of diamines and polyamines - Google Patents

Description

Continuous process for the production of diamines and polyamines The invention relates to a continuous process for the production of Diamines and polyamines, d. H. compounds containing multiple nitrogen atoms which include ethylenediamine and piperazine, by passing over ethanolamine and Ammonia over a fixed bed of hydrogenation catalyst under pressure and at elevated temperature.

It is known the implementation of ethanolamine with ammonia in one certain molar ratio at temperatures of about 150 to 250 "C under continuous Passing the mixture to be converted through metallic, z. B. ruthenium catalysts to be carried out in liquid, vapor or mixed phase. This method however, requires relatively long reaction times and leads to relatively short ones Exploit.

According to the invention, at steady and pronounced speeds Ethanolamine in a mixture of compounds containing several nitrogen atoms, such as piperazine and ethylenediamine, are reacted so that a stream of ethanolamine and ammonia, in which the molar ratio of ammonia to ethanolamine is at least 3: 1, at temperatures between 150 and 225 "C and under a pressure of 70 to 175 kg / cm2 passes over a fixed bed of a Raney nickel catalyst and then in a manner known per se, the ammonia is removed from the stream and the reaction products isolated. There can be conversions of up to about 70 to 80 ° / 0 with relatively short residence times can be achieved over the catalyst bed.

Ethylenediamine, piperazine and diethylenetriamine are among these Compounds containing several nitrogen atoms to be prepared according to the invention. The achievable piperazine yield can in a predetermined manner over a large range can be varied, with up to 300 / o or more of the reacted in a single pass Ethanolamine can consist of piperazine. Relatively higher temperatures within of the stated range such as the presence of relatively larger amounts of the catalyst at fixed ethanolamine feed rates or adherence to relatively longer periods Contact times with the catalyst lead to higher yields of piperazine. So enables z. B. a pressure of 140 kg / cm2 and a molar ratio of ammonia to ethanolamine of at least 5: 1 often a yield of 25 to 300 / o or more of this compound.

Conversely, the yield of piperazine can optionally be reduced if a mixture with higher ethylenediamine yields are lower by application Temperatures, large amounts of ammo niac or lower relative amounts of catalyst or shorter contact times with this should be maintained. Generally arise depending on the conditions between 5 and 200 /, of the converted ethanolamine as diethylenetriamine.

For the implementation of the method according to the invention is used as a metallic Hydrogenation catalyst used Raney nickel that is on a support such as alumina (Aluminum oxide) or finely divided silica, can be applied. Attractively priced is the application of at least 0.454 kg of a Raney nickel catalyst for each 1.361 to 1.814 kg of the ethanolamine to be reacted per hour when passing over a fixed catalyst bed. The dwell time of the starting material to be converted this should not exceed 1 hour. This time depends on the changes in operating conditions, e.g. B. the pressure, the temperature and the relative amount of the catalyst used.

From the stream withdrawn from the catalyst bed can then subsequently the ammonia is removed in a known manner and the reaction products are isolated. Generally this is done by distillation. For the isolation and cleaning of the however, various connections are also any other desired and required Combinations of condensation, extraction with solvents, or distillation Precipitation applicable.

Example 1 1.41 kg of a Raney nickel catalyst was used as a solid Catalyst bed in a cylindrical reaction vessel with a catalyst filling 58.42 cm and an inner diameter of 5.08 cm brought in. A stream of 0.998 kg of ethanolamine per hour and 3.5 moles of ammonia per mole of ethanolamine was under an average pressure of 137kg / cm2 at an average Temperature of 195 "C passed continuously over the catalyst. The individual Residence time in the passage of the ethanolamine to be reacted over the bed was about 26 minutes. About 75 percent by weight of the ethanolamine was continuously in converted a mixture of different compounds containing several nitrogen atoms, from the average 24.1 0/0 ethylenediamine, 29.80 / 0 piperazine and 14.250 /, Diethylenetriamine were isolated. The individual compounds were from the reaction mixture, that is withdrawn from the catalyst bed after stripping off the unreacted ammonia was, separated by distillation through a packed column and recovered.

Example 2 The reaction was carried out in the same reaction vessel in which the same amount of Raney nickel catalyst was present, with the difference carried out that the temperature 160-170 "C, the ethanolamine feed rate 0.726 kg per hour and the molar ratio of ammonia to ethanolamine in the approach about 3.3: 1 was. The result was a yield of 12.5% piperazine, based on the amount used Amount of ethanolamine, while for ethylenediamine and diethylenetriamine 50.50 / 0 and 9.30 / 0, respectively.

Example 3 In a similar experiment, one feed rate of 1.2 kg per hour, an ammonia-ethanolamine ratio of about 5.6: 1, one average pressure of 105kg / cm2 and temperature conditions of 165 "C worked.

The yield of piperazine was practically zero after conversion, However, it was 60.8% of ethylenediamine and 16.340 / 0 of diethylenetriamine on the amount of ethanolamine used.

In all cases a certain proportion of the ethanolamine was in higher Amines transferred. The conditions for major conversions to piperazine also tend to a reduction in the formation of higher molecular weight amino compounds.

In many cases it is advantageous to use the unreacted ethanolamine including the ammonia returned to the circuit for greater overall conversions of starting materials, greater yields and economic advantages in operation achieve.

Were used for comparison with the working methods explained above analogous reactions of ethanolamine according to the known batch process below Use of a pressure bomb apparatus and the same catalyst under the same reaction conditions carried out, then the largest implementations occurred within about Istündiger Time periods only approximately 30 to 350/0.

Patent claimsR: 1. Continuous process for the production of Di- and polyamines by passing ethanolamine and ammonia over a fixed Bed of hydrogenation catalyst under pressure and at elevated temperature, d a d u r c h characterized that a stream of ethanolamine and ammonia in which the molar ratio of ammonia to ethanolamine is at least 3: 1 at temperatures between 150 and 225 ° C and under a pressure of 70 to 175 kg / cm2 over a fixed Passes bed of a Raney nickel catalyst and then in known per se Way, the ammonia is removed from the stream and the reaction products isolated.

Claims (1)

2. The method according to claim 1, characterized in that at least 0.454 kg Raney nickel in the fixed bed for 1.361 to 1.814 kg of the to be converted Ethanolamine can be applied. 3. The method according to claim 1 and 2, characterized in that the Raney nickel is applied to a carrier. 4. The method according to claim 1 to 3, characterized in that the Residence time of the ethanolamine to be reacted on the fixed Raney nickel bed Does not exceed 1 hour. Documents considered: British Patent No. 747 841.