DD201785A5 - PROCESS FOR THE PREPARATION OF AMINO PYRIDINES - Google Patents

Abstract

Amino-pyridines are prepared by treating glutaric acid dinitriles with H 2 in the presence of Pd catalysts on alfa-AL deep 2 O deep 2-gels in the gas phase at temperatures of 260 to 310 ° C.

Description

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Process for the preparation of amino-pyridines

Field of application of the invention

The present invention relates to the preparation of amino-pyridines of the general formula

in which R represents a hydrogen atom or a lower alkyl radical having 1 to 2 C atoms.

Characteristics of the known technical solutions Amino-pyridines provide starting materials for the production of chemotherapeutically active substances and pharmaco-.

logically significant connections.

Explanation of the essence of the invention

The process of the invention is characterized in that glutaric acid dinitrile of the general formula

NC CN in which R is a hydrogen atom or a lower alkyl radical having 1 to 2 C atoms, in the gas phase, together with hydrogen at temperatures of 260 to 310 ⁰ C via a Pt or Pd catalyst, which on an 'α- ΑΙ-, Ο-carrier is applied, conducts.

In addition to glutaric acid dinitrile, it is also possible to use substituted glutaric acid dinitriles, preferably 2-methylglutaronitrile. A particularly advantageous embodiment of the invention is when 2-methylglutaronitrile

is to be reacted, starting from a mixture of methylglutaronitrile and Alky! succinonitrile, as obtained as a byproduct in the adiponitrile production.

The glutaronitrile is conveniently used in an amount of from 0.1 to 1.0 g, preferably from 0.3 to 0.5 g per gram of catalyst per hour.

The amount of hydrogen is advantageously from 0.5 to 1.0 liter of hydrogen per gram of catalyst per hour.

The reaction temperature is advantageously from 280 to 300 ^° C.

The catalyst used is platinum or palladium, which is applied in amounts of from 1 to 10% by weight, preferably from 1 to 5% by weight, to a support of c-Al-O.

As α-Α1_Ο as a carrier is suitably such q-A1 O in question, which has a specific surface area of 100 rn / g

2 2 2

to 350 m / g, preferably 250 m / g to 300 m / g.

The heated to reaction temperature mixture of glutarodinitrile and hydrogen is passed over or through the catalyst support. In this case, the catalyst support may be present as a fixed bed or as a fluidized bed.

The reaction mixture obtained by the process of the invention consists of non-reacted compounds in the form of a solid material

recovered: aminopyridines and other pyridine bases. In addition to 2-aminopyridine, glutarodinitrile produces even greater amounts of pyridine and butyronitrile, which can be separated off and reused. If methylglutaronitrile is used, in addition to 2-amino-3-picoline and 6-amino-3-picoline, even larger amounts of 3-picoline are precipitated, which are separated off and fed to a further intended use.

embodiments example 1

210.4 g of a mixture of 86.4% 2-methylglutaronitrile and 13.2% Aetylsuccinodinitril, as obtained in the adiponitrile as a byproduct, were at 28O ⁰ C together with 30 liters of H per hour for 10 hours through a catalyst bed of Pd pumped on g-AljO, (5% Pd) in spherical form. After collecting the reaction product (194.9 g), the following products were isolated:

23% unreacted methyl glutaronitrile 23% 2-amino-3-picoline

14% 6-amino-3-picoline

14% picoline

further about 17% of valero and 2-methylbutyronitrile.

For a conversion of about 75%, aminopicolines were obtained in a yield of 54% and 3-picoline in a yield of 22%.

Example 2

Similar to Example 1, but at 310 ⁰ C, glutarodinitrile were pumped through the catalyst together with 20 liters H / g catalyst / h during 6 hours. This resulted in 2-aminopyridine in a yield of 26.9%. In addition, 29.9% pyridine was found.

Examples 3-5

at Quantity g reactant ESN 7 H ₂ Temp. yield , 4 % , 9 i game per g cat. per h 11 l / h ⁰ C /8th ,8th 0.3 .-MDGN 7 2 3-picoline 3 Amino-3-picoline , 4 3 0.5 87.8 13 10 300 28 29 4 0.48 93 10 280 4.8 , 47 5 86.4 30 260 36 30

ι ι

Example 6

In contrast to Examples 1, 2, 3, 4 and 5, a platinum catalyst was used here: 1% Pt on a support of α-Al 0 In principle, however, the same procedure was used as in the preceding examples.

reactant kind MGN% ESN% ^H 2 l / h. Temp. ⁰ C Yield% Amino-3-picoline Quantity g per g of catalyst per h 100 - 20 310 3-picoline 23 0.4 1 1

Claims (5)

ürfindungsanspruch 1. A process for the preparation of amino-pyridines of the general formula in which R represents a hydrogen or a lower alkyl radical having 1 to 2 carbon atoms, characterized in that the corresponding glutaric acid of the general formula ./ ^"1 ^ R · CN in which R has the abovementioned meaning, in the gas phase, together with hydrogen., At temperatures of 260 to 310 ⁰ C, via a Pt or Pd catalyst, which is supported on an a-Al ^ O carrier, directs. 2. The method according to item «1, characterized in that one leads Glutarsäuredinitril in an amount of 0.1 to 1.0 g / g of catalyst / h over the Katalysatoratpr. 3. The method according to items 1 and 2, characterized in that one uses hydrogen in an amount of 0.5 to 1.0 l / g Katalyt / h. 99 iÄR7  fev * 4. Method according to points 1 to 3, characterized in that the Pt or Pd catalyst is applied to an α-Al 0 support, the one, specific 2 2 Surface of 100 m / g to 300 m / g. 5. Method according to points 1 to 4, characterized in that the porosity of the carrier for the Pt or Pd catalyst determined α-Al O_ has a proportion of micropores of 0.15 cm / g and a proportion of macropores of 0.010 cm / g.