DE1048884B - Process for the preparation of dilute aqueous hydrazine solutions - Google Patents

Description

GERMAN

F 23648 IVa / 12 i

REGISTRATION DATE: JULY 31, 1957

NOTICE THE REGISTRATION AND ISSUE OF THE EDITORIAL: 2 2. J A N IJ A R 19 5 9

The recovery of hydrazine hydrate from dilute aqueous solutions, as z. B. in the Raschig synthesis incurred is very cumbersome and also requires a considerable amount of money. To this one reduce, one could take advantage of the fact that by distillation of aqueous hydrazine solutions In the presence of suitable amounts of acetone, distillate functions can be obtained whose hydrazine content larger than that of the swamp. However, when using the usual destination ίο method difficulties in such a way that a hydrazine-rich distillate is first obtained, the sump, however, is more rapidly depleted of acetone than hydrazine, which leaves a large part of the hydrazine behind. Continuous addition of acetone to the sump is practically ineffective.

The invention relates to a method for processing hydrazine hydrate from dilute aqueous solution by distillation with acetone, which consists in that the components in liquid Condition and homogeneous solution from the distillation can be stored for a finite time, about 10 minutes and acetone addition and storage are repeated in stages during the process as soon as the The acetone content of the solution has decreased too much.

It was found to be advantageous to set the molar ratio of acetone to hydrazine between the values 2.2 and 0.8 keep. Thereafter, the ratio 2.2 would have to be set each time before the start of the distillation and this in the to continue the respective level until the value 0.8 is reached.

example

The process can be carried out in the following way in an apparatus according to the attached sketch: The charging vessel 1 contains a mixture of 2% hydrazine hydrate solution and 50 g / l acetone, which were present in a homogeneous state at least 10 minutes before the start of operation. Of this solution, 3 to 4 liters per hour are continuously applied to the topmost of the separation columns 2. The residence vessels 3a and 3b are continuously charged with acetone through the nozzles provided for this purpose, namely vessel 3a with 20, vessel 3b with 7 g / h. The sump bubble 6 is supplied with enough heat by heating it by means of a gas flame that, after condensation in the cooler 4 in the distillate receiver 5, about 500 processes for the preparation of dilute aqueous hydrazine solutions

Applicant:

Paint factories Bayer Aktiengesellschaft, Leverkusen-Bayerwerk

Dr. Erich Rahlfs, Dr. Werner Thraum, Leverkusen, and Dr. Günter Henrich, Opladen, have been named as inventors

up to 600 cm ³ per hour. So much liquid is continuously withdrawn from 6 by setting the stopcock appropriately that the bladder is constantly half full. The vessels 7a and 7b represent storage vessels for acetone.

The bottom drain is practically free of hydrazine and acetone, while these components are accordingly find enriched in the distillate.

Claims (3)

PATENTED KITCHEN: 1. Process for the preparation of dilute aqueous hydrazine solutions by distillation with Acetone, characterized in that the components are in liquid state and homogeneous solution Before the distillation, store for a finite time, about 10 minutes, and add acetone as well as storage can be repeated in stages during the course of the process. 2. The method according to claim 1, characterized in that that the molar ratio of acetone to hydrazine to be set before the distillation is 2.2 and the renewed setting to this amount after falling below the value 0.8 he follows. 3. The method according to claim 1 and 2, characterized in that the distillation is continuous takes place in a fractionation apparatus, the separation column of which is interrupted by retention vessels, added to the acetone and in which the solution is stored. 1 sheet of drawings