DE1064954B - Process for the production of unsymmetrical dialkyl hydrazines by catalytic reduction of dialkyl nitrosamines - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

kl 12 q 13

INTERNAT KL C 07 C

PATENT OFFICE

EXPLAINING PUBLICATION 1064 954

O5211IVb / 12q

REGISTRATION DATE NOVEMBER 24, 1956

NOTICE
THE REGISTRATION
AND ISSUE OF THE
EDITORIAL SEPTEMBER 10, 1959

The invention relates to the production of unbalanced Dialkyl hydrazines, such as ζ Β 1,1-dime thylhydrazm, by catalytic reduction of dialkylnitrosames 1,1 Dimethylhydrazine has already been made in various ways in a laboratory process Dimethylmtrosamm was reduced with zinc and acetic acid Also other Reduk media were used, but all for the Use on an industrial scale is too expensive ζ B 2 Ethylanthrahydroquinone, Sodium sulfoxylate, Hydrogen sulphide and indigo white There is a pro in the reduction of dimethylnitrosam poor to achieve yields that are economical are interesting and furthermore losses, in particular by overreduction to the economically less valuable dimethylammon and ammonia, to avoid

According to the invention, an asymmetrical dialkyl chloride is used produced by the fact that the corresponding Dialkylmtrosamm with hydrogen in The presence of a nickel, copper chromite or palladium-on-alumina hydrogenation catalyst converts The process gives excellent results in both batch and continuous operations Yields of a high quality product

Ranevnickel is on all of the investigated catalysts ren most advantageous and gives the highest yields and degrees of conversion without the formation of noticeable amounts of overreduced products catalysts from copper chromite or palladium on alumina give satisfactory results, while other common hydrogenation catalysts such as dispersed copper, Raney cobalt, and other kata Analyzers, Delivering Extremely Poor Results Long-Distance Copper ζ B was found in three out of four Do not try any reduction and at that fourth attempt a yield of only 7% Raney nickel however, consistently gives excellent results, usually becoming final Yields of 90% and more achieved

When using Raney nickel or palladium the reduction can be carried out on alumina at temperatures between 0 and 100 ° C the most appropriate and preferably applicable temperatures are between 25 and 50 ° C below Half of 25 ° C, the reaction may take place slowly and above 50 ° C a noticeable Use borrowed overreduction with the formation of dialkyl lamb and ammonia. Optimal results were achieved at around 30 ° C, copper chromite, a somewhat less active catalyst, can be achieved at temperatures between 0 and 175 ° C

Hydrogen pressures between about 84 and 140 kg / cm ² and more are favorable because the reaction occurs at higher

procedure

for the production of unbalanced

Dialkylhv ^ drazmen by catalytic

Reduction of dialkyl nitrosams

Applicant:

Olm Mathieson Chemical Corporation,
Baltimore, Md. (V. St. A.)

Representative Dr W Beil, lawyer,
Frankfurt / M -Hochst, Antoniterstr. 36

John Wilbur Churchill, Kenmore, N Y,

and John Fesster Haller, Hamden, Conn (V St A),

have been named as inventors

Printing is faster. Optimal results have been achieved in the vicinity of 112 kg / cm ² , while only small amounts of the desired product are obtained by reduction with pressures in the vicinity of normal pressure

The Dialkylmtrosamme can according to the invention without solvent or in aqueous or non-aqueous Solvents are hydrogenated in solution Aqueous solutions with a concentration of only 10% or less to 90% or more can be used as the starting material in the stronger In dilute solutions, the reaction takes a little longer it ei off, but maintaining the temperature is easier The more concentrated solutions have the advantage that they make the production of a plant of certain size increase and a relatively concentrated Dialkylhydrazine produce if aqueous Lciingen are used, they should be neutral or alkaline but preferably not acidic

The catalytic hydrogenation of dialkylnitrosam can be carried out batchwise or continuously in a suitable pressure system discontinuous work is a suspension of Raney nickel, expediently in water, at for example mixed with aqueous Dimethylmtrosamm and put the latter in a reaction vessel is closed with hydrogen until it is reached of the desired pressure and adjusted to a suitable nete reaction temperature heated. in which it is consumed while the pressure is on

Keep constant throughout the entire procedure, depending on the quantity and quality of the kata lysators, the concentration and amount of the solution, the reaction takes 30 minutes to 5 hours When working discontinuously, the kata is cherished lysatoi amount usually between about 0.1 and 5%, preferably at about 1% die for complete Reduction to dimethylhydrazine required time increases when the concentration and the amount

The mixture was kept at a temperature of 25 ° C under a hydrogen pressure of 112 kg / cm ² for 7.25 hours. During this time, 0.254 grams of moles of 1,1-dimethylhydrazine were formed. The yield was 33.5%

Example IV

A 15% aqueous solution containing 0.13 grams mol of dimethylnitrosamm was increased with 5 cm ^{3 of} the dimethylhydrazine solution and the amount of a slurry of about 3 g of freshly prepared catalyst was reduced ^ Raney nickel in alcohol in a pressure-tight reaction

When working continuously, a cata- lyst is filled with a hydrogen pressure of 112 kg / cm ² gate layer which is preferably made of Raney nickel and a temperature of 30 ° C for 17 minutes, a particle size of less than 84 mm is maintained in a. The resulting solution contained, vertically arranged cylindrical pressure vessel 15 as determined by titration with potassium] odate. Aqueous dimethylnitrosamm was flowing, 0 060 gram mol 11 dimethylhydrazine, ent through the catalyst layer downwards
Appropriate hydrogen pressures are calculated in the system. The draining aqueous liquid
which contains the 1,1-dimethylhydrazine is then used for the 20th
Extraction of the product treated for separation
the non-aqueous layer containing the 1,1 dimethyl

hydrazine and unreacted dimethylnitrosam, which are separated from one another by fractionation

corresponding to a yield of 48 7% Example V

In the case of discontinuous hydrogenation, the of Example III was similar to 0 406 gram moles of dimethylnitrosamm in the form of a 30% strength aqueous solution used The catalyst used consisted of 3 g of already used Raney

The can, contains, can be added to the alkali. Nickel that has been slurried in 5 ecm of water can be used. Other separation processes, ζ B precipitation as a salt
are unreacted dimethylnitrosamm and
Hydrogen are fed back into the process

Example I.

In a steel bomb set up as rubble a solution of 225 g of dimethylnitrosamm in 270 g of water was filled 30 g of Raney nickel were trains

was

and a pressure of 112 kg / cm ² 3 ³ Å »hours, 0 282 grams mol 1.1 dimethylhydrazine, corresponding to a yield of 69 5%, were formed

Example VI

A 90% solution of dimethylnitrosammon in water containing 0 606 gram-moles of nitrosammon sets, and hydrogen was introduced up to a pressure of 35 at room temperature with 9 g of nickel sponge 70 kg / cm ^2. The bomb was at 22 ° C Shaken as a catalyst at a hydrogen pressure for 140 minutes The liquid content of the
Bomb was poured out and filtered the on
425 g of liquid obtained in this way corresponded to
an insert of 192 g of dimethylnitrosamm The 40
Titration of the liquid showed a content of

a water pressure of 112 kg / cm ² 2 hours and 38 minutes reduced The amount of 1,1-dimethylhydrazine formed was 0.317 gram-mol and the yield was 52.4%

Example VII

93.3 g of 1.1 dimethylhydrazine compared to A catalyst layer was prepared by

the theoretical value of 155 5 g, a yield one a column with a diameter of 23 mm

of 60% corresponds to the 1 1 dimethylhydrazine 20 5 cm high with particles from 42 per weight

45 percent nickel and 58 percent by weight aluminum were separated by adding 50% alkali

The non-aqueous layer was isolated with solid Shaken with alkali, separated from it and distilled. A 65 g fraction of 99 to 100% strength 1,1-dimethylhydrazine with a boiling point of 62 to 64 ° C. at normal pressure was obtained

Example II

In this discontinuous hydrogenation, 3 g of Raney nickel, which had been produced in a known manner by the action of aqueous alkali on a nickel-aluminum alloy, were mixed with 100 g of 10% strength aqueous dimethylnitrosam and introduced into a bomb. Then hydrogen was up to a pressure of 112 kg / cm ² and the temperature 14 minutes at about

standing alloy of a particle size between 0 50 and 0.25 mm and a filled l% strength Alkahlosung poured through the layer, a Raney nickel Kataly sator manufacture The alkali was removed by washing 5 <fc ~ with water removed the column was running at * Water cooled in a cooling jacket. A 10% aqueous solution of dimethylnitrosamm was introduced into the top of the column at a rate of 6 cc / min, while a hydrogen pressure of about 70 kg / cm ^{2 was maintained} in the column. The material flowing off was checked and titrated with sodium nitrite solution The yield of 1,1-dimethylhydrazine achieved in a single pass was 14%

Maintained 25 ° C. The solution obtained contained how was determined by potassium iodate titration, 3.12 g of 11 dimethylhydrazine The yield was therefore 38 6%

Example III

In this discontinuous hydrogenation, 0.757 grams moles of dimethylnitrosamm were in the form of a 50% aqueous solution together with about 75 g

Example VIII

55 g of dimethylnitrosamm were in a Schiit telautoklav without solvent at 175 ° C for 1 hour at a hydrogen pressure of 106 kg / cm ² and using 4 g of copper chromite as catalyst h) The catalyst was filtered off and washed with methanol Product combined, and all the liquid was fractionated at normal pressure

1% palladium on alumina in a bomb was subjected to distillation. First, the mixture was subjected

from methanol and 1,1-dimethylhydrazine and thereafter unreacted dimethylnitrosamm obtained Das the latter could be used again. The 1,1-dimethylhydrazine was separated as the hydrochloride by adding hydrogen chloride to the methanolic Introduced solution of the base at 25 to 35 ° C, filtered, washed and dried it melted at 83 ° C (literature value 81 to 82 ° C)

Example IX

30 g of Dimethj lnitrosamm in a 60 weight percent aqueous solution were hydrogenated with Raney nickel at a hydrogen pressure of 35 kg / cm ² and temperatures increasing from 50 to 100 ° C. for a total of about one hour. The product was hydrogenated by the reduction identified by Fehhng's solution

The present invention can be broadly defined the production of asymmetrical dialkylhydrazines, preferably those in which each alkyl radical contains no more than 5 carbon atoms turn Such hydrazines can be Herge provides that in place of the in the special Examples used dimethylmtrosamine ζ Β Methylethylnitrosamm, diethylnitrosamm, Di η as propylmtrosamm or di η butylmtrosamm are used

Claims (7)

Claims 1 Process for the preparation of unsymmetrical Irish dialkyl hydrazenes by catalytic Reduction of dialkylnitrosams, thereby ge indicates that one dialkylnitrosarmne with Hydrogen in the presence of a nickel, or copper chromite Palladium on alumina hydrogenation catalyst reduced 2 The method according to claim 1, characterized in that a nickel or palladium Alumina hydrogenation catalyst at a Temperature between 0 and 100 ° C used 3 The method according to claim 2, characterized in that a reaction temperature between see 25 and 50 ° C applied 4 Process according to Claim 2 or 3, characterized in that the catalyst used is Raney nickel used 5 The method according to claim 1, characterized in that a copper chromite hydrogenation catalyst used at a temperature between 0 and 175 ° C 6 The method according to claim 1 to 5, characterized in that dialkyl nitrosams as Starting compounds used whose alkyl radicals each have no more than 5 carbon atoms contain 7 The method according to claim 6, characterized in that one dimethylnitrosamm as the starting compound used Older patents considered
German Patent No. 1 037 464 © 909 627/408 9