DE1543839A1 - Process for the preparation of aminonitriles - Google Patents

Description

Dr. F. Zurmtein - Dr. E. Assmann

Dr. R. Koenigsberger
Dipl. Flv's. R. HoYouuer

L »"'<* l / IU' 3 ^£ f OOO

MGndien 2, Liuuhaussiroye 4 / IH

SC 2769

RH (MIE-POULEKCr S.A. »Paris, France Process for the preparation of aminonitriles

The present invention relates to a method of manufacture of aliphatic aminonitriles from lactones. In particular, she meets a process for the production of 6-aminohexanenitrile from caprolactara.

The O-aejinonitriles are valuable products because they are advantageous Represent access route to diamines and 6? -Amino acids, the Usually used in the manufacture of polymers.

It is known to CO -Aminonitrile by various processes (selective reduction of dinitriles, exposure to ammonia C £ ~ chloronitrile). It is also known to produce them by adding the corresponding lactams with ammonia in the

909881 /. 1519 .bad ORIGINAL

Vapor phase are reacted in the presence of a dehydration catalyst (French Patent No. 1 163 699), wherein an indispensable condition for a good reaction process is »that this catalyst has a neutral reaction in water Has.

The object of the present invention is to create an advantageous process for the preparation of aminonitriles.

It has now been found that aliphatic O-aminonitriles of the formula HgN-R-CN, in which R denotes an alkylene radical, can be prepared by using lactams with ammonia at temperatures in the order of magnitude of 250 to 450 ° C. in the presence of a water separation catalyst acid reaction in water "

The lactams that can be treated according to the invention correspond the general formula

in which R is an optionally substituted group means, where η represents a value between 3 and 12. Man can for example treat caprolactam, capryllactam or lauryllactam.

909881/1519

The catalysts are catalysts with an acid reaction in water » such as phosphoric acid on a carrier »boron phosphate» mixtures of inorganic acids and / or their anhydrides. Man uses these catalysts in granular form »being the size the grain t can be up to 10 mm »although this information is not a restriction.

The reaction corresponds to the equation K I ■ + NH, * - HoN-R CN «■ HoO

j + NH ₅ * - H ₂ N = R CN <■ H ₂

In practice, an excess amount of ammonia is used and preferably uses 6 to 20 moles of NH per mole of lactam, since an excess of ammonia favors an increased degree of conversion and avoids the formation of by-products.

The reaction is advantageously carried out "by the Ge is mixed is circulated by Laeteindampfen and gaseous ammonia through the accommodated to a temperature of 250 to 450 C ^6, and preferably from 350 to 4Io ^e C catalyst. The reaction components are fed into the reaction vessel in such an amount that the contact time in the catalytic zone is a few seconds. At the outlet of the reaction vessel, the organic products are condensed and the desired one is separated

90 9881/15 19 BATHROOM ORLIGATION

Aainonitrile and the unconverted lactam by distillation,

The following examples illustrate the invention without restricting it.

example 1

In a tube made of Pyrex glass with a diameter of 40 μm and a height of 7 ¹ K) mn, 126 g of a catalyst are introduced into the middle zone (height of the catalytic bed 160 mm), which is obtained by calcining a mixture of 376 g 86 Current phosphoric acid and 186 g of boric acid at 600 ° C and subsequent crushing to grains of 1.25 to 2 mm, a layer of Raschig rings made of glass at a height of 280 mm Hg, which is used to preheat the reaction components. At the same time, ^{ammonia 1 preheated to JTO 0} C is introduced into the upper part of the tube in an amount, measured at 20 ° C and normal pressure, of 200 l / hour and to 100 ° C preheated liquid caprolaotam at a rate of 60 g / hour. The steam / catalyst contact time is thus 1.4 seconds and the ammonia / caprolactam molar ratio is 15.5. The tube is heated by means of a furnace, and the temperatures are in the preheating zone 317-382 ⁰ C and in the catalyst bed 382 to 402'Co The au "the pipe exiting products are collected in a cooled flask in the dea

BATH ORIGINAL

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Reaction products condense * while the separating and reading ammonia escaping from the upper part of the flask in one filled with Raaohig rings, continuously with ethyl alcohol sprinkled column is absorbed. After 3 hours, the operation is terminated * whereby 182 g of caprolactam are obtained has treated. The products condensed in the flask are then combined with the washing alcohol and the ethyl alcohol is removed by evaporation and distilled the remaining product. A first fraction of bp ^ 105 to 120 ° C. is isolated in this way, which

Weighs 117 * 9 g, and a disputed fraction of Kp _n , »87 to 112 * C,

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which weighs 59 »1 g and consists only of non-converted caprolaotam consists. Bine determination by gas phase chromatography shows that the first fraction of 114 g of Cd-annocaprooneltrile, 2.7 S Hexen- (5) nitrile and 1.2 g of caprolactam.

The yield of CO-aneinocapronitrile is therefore 9 ** 3 % * based on the carpolaotam consumed, the degree of conversion of the caprolactam being 67 % .

Examples 2 to 5

The procedure is as in Example 1, but certain reaction conditions are varied and the table below gives the following: staggered results:

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\ n «« «ch o \ Os cn

in m

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-sr in 15A3839

BATH ORIGINAL

90988T / 15Ί y

Example 6

In an apparatus * which is identical to that of Example 1 * brings 156 g of a catalyst which consists of phosphoric acid applied to kieselguhr (content of P ₂ ⁰ K ⁵ 57 £) ^with a particle size of 6 to 8 ma. While keeping the tube at 36O to 567 ^e C, used is caprolactam and ammonia in order under the conditions of Example. 1 GJ-aminocapronitrile is obtained in a yield of 90 % with a degree of conversion of £ 20 and only 3 % hexene ~ (5) -nitrile.

9 0 9 8 8 1/1 5 Ί ä _BA0

Claims (1)

Claim Ancestors for the production of allphatisohen Aninonitrllen der Ponael HgN-R-CN, in which R is an optionally substituted one Alkylene radical means “characterized” that nan a Caprolactan of the formula ■ with ammonia in contact at a temperature of 250 to * 50 * C nit a dehydration catalyst «which gives an acidic reaction in an aqueous medium» ». BATH ORIGINAL 909881/15 19