DE1922535A1 - Stabilized aromatic amine mass and process for its preparation - Google Patents

Description

D ... mTTÄMCKi ■■ ··· ■: =. · "·!: ■■ · '■ - MÖNCHEN 5 DIPL.-ING. H. BOHR. '.: .. \. *. MOLLERSTR. 31 DIPL-ING. S. STAEGER. - May 2, 1969 Description * ' ^{nMI iaba}

on the patent application of Imperial Chemical Industries Limited, London, S.W.1., England,

concerning:

Stabilized aromatic amine mass and process for its preparation

The priority of filing in Great Britain from 3 * 5.1968

is used

The invention relates to stabilized aromatic amine compositions.

With aromatic amines takes place on contact with air an oxidation takes place, so that a discoloration occurs during storage. In some cases the discoloration is so severe that even temporarily stored amines are no longer suitable as intermediates. The use of freshly distilled Amines in the chemical industry is not always possible in practice, and it is known that certain amines to reduce the discoloration during storage, adding substances that act as stabilizers. As a stabilizer for Alkarylamines, carbon disulfide and its derivatives, e.g., isopropylxanthogenic acid and its sodium salt, have been suggested been. As a stabilizer for aromatic amines of the formula: B-HBU, where R is a naphthy radical or a phenyl radical with 1 to 2 from NHp, alkyl groups with 1 to 4 carbon atoms and alkoxy groups with 1 to 4 carbon atoms Represents chosen substitution groups, are alkali metal primary alky! xanthates have been proposed in which the metal has an atomic weight between 22 and 40 and the Alkyl group contains 3 to 5 carbon atoms.

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According to the invention, a stabilized aromatic amine mass consists of one of the aromatic amines 4-chloro-2-methylaniline and o-anisidine mixed with potassium ethylxanthate. - '

The proportion of Ealiumatbylxanthate in the stabilized aromatic Amine can be very small - expediently in the range of e.g. 0.001 to 0.5%, preferably 0.001 to 0.1% by weight based on the aromatic amine - be. In particular, 4-chloro-2-ethylaniline is obtained by incorporating 0.001% by weight of potassium ethyl xanthate effectively stabilized.

The potassium ethylxanthate can be incorporated into the aromatic amine in any desired manner. It will be fatal incorporated into freshly distilled amine, for example by placing the amine in a gate layer containing potassium ethylxanthate is distilled into it. It is also advantageous if one works in such a way that the amine hardly comes into contact with the Air comes. The incorporation can also be carried out in such a way that the potassium ethylxanthate is mixed with liquefied amine and the mixture obtained is caused to solidify, or that the solid (e.g. granular) amine with potassium ethylxanthate e.g. mixed in a drum mill.

If so desired, the haters can also use the invention other substances, e.g. inert solvents and diluents, contain.

- 3-

9098A9 / U90

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According to the invention, the wet ones remain stable for many years under normal storage conditions, even if they are in contact Bit for plants and containers used metals, such as Elsen and aluminum, come. Your shelf life is that of the corresponding cash registers with those proposed so far Superior to xanthates as stabilizers.

The invention is explained below with reference to exemplary embodiments purely for example explained in more detail, the percentages being based on weight:

example 1

In the production of 4-chloro-2-methylaniline, the crude product, which is obtained by chlorination of acetyl o-toluidine and Bydrolysis of the resulting mixture is generated by Vacuum distillation cleaned

Samples from the freshly distilled product were placed in glass bottles, some of which contained 0.01% potassium ethyl xanthate, brought in. To accelerate the test, the samples were kept in the molten state at 30 - 35 ° C in the dark. The samples were removed from the bottles at intervals and the deterioration in color was recorded in each case 50% solution in xylene on the basis of the scale of Bazenel units measured. The result can be seen in Table I:

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! Table I.

Storage time control (without addition) samples at $ 0.01

Potassium ethyl xanthate

(Vague) (Hazen units) (Hazen units)

O 100 100

14-160 200

28 600 200

42 1250 200

Other samples were subjected to the accelerated shelf life test subjected in the presence of iron and aluminum. The result can be found in (Table IZ:

Table II

Storage control in the presence of samples containing 0.01% potassium time iron aluminum ethylxanthate in present. from

Iron aluminum

(Days) (Hazen units) (Eazen units)

100 200 100 1040 200 80 2020 240 110 2420 200 160 3000 270

The experiments described in this example were repeated with 0.001 # potassium ethyl xanthate. After a storage time of 4 months the results were the same as those with 0.01% potassium ethyl xanthate.

Example 2

In the production of o «anisidine the crude product, the

is obtained by reducing o-nitroanisole, by vacuum

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0 200 10 600 2Q 1600 42 1400 78

* * Ii (in ♦ * · ^a ·· * »* i *

I · I IM ^l '

purified by distillation. While de? Production were twelve Ί3,6 kg samples of freshly distilled Prodiafcfe ia inside lacquered UJroissiölaa from Plissstshl © Isgiiteaetit "Sia s @ © lxs this Eroben were _$ 1 564 g (0.01 $) Xaliunätli ^ lacanthBt each as Stafeilisiermitt ©! admitted »Si © Steonmslm mart ©» v © r «so! 0.oss © n wad at Ifegeis'imgstemperatiia» @ t®Si @ ag © las® @ fi »Eat distances from each state wsi'ämi until then unopened troaaela with the stabiliai @ i? t®B miß * mlefat stabilized Hass © geöffa @ 1i ₉ imd Bp® "b © ia wttd®ag (& a® ^ a © a _e The Aue * seeing of the samples was with the Mg © 'beiwtielts imd di @ optical sight vmrde with © inea Uni © am »SF« 8OO-Sp © kt3? @ e © taa? with 1 cm cells at 520 mte nand 428 from according to © 3 © © ii _e Bi © E ^ The results can be found in Table 211

table III

Storage control (without additions) ^ © "ben with O ₉ 01% E & iiumäthylzeit Appearance optical density at xänthat

525 mfei 428 mto appearance optical sight at (Hot) '(yellow) ^ 23 χφ 428 mtei

(Months) (H © t) ^r (yellow)

O
1 Clear color »
loose flue »
sweetness
small amount
docile pink 0
0 ₉ 08
, 23 e »a
0s5? Clear color »
go © FlSs- ι
slightly,
Mass yellow 0.22 2 red-brown 0 0.28 0.15 3 red-brown -0 0.33 B ( 0.137 VJl Brown ⁰ , 332 0.688 ₍ 0.126 O ₉ OQ
0.05 0.04 9 ₉ © 4

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Claims (1)

t 1 1 1 * J) / 1 \ Stabilized® or 0-AnisidiB la Hfsetemg with eiasm B thereby g # kssfflseietmet _t that as jStais e.g. «la, eiaar Hesga ^c f @ a 0.001 M Asia is chosen * X ^ ® ^ £ & / _{f ,?} 2. Stabilized asssiEflseli © imlaiaase ^ as ^ la Mmm ^ & mh 1 “gek ^ xmsaichneii» that si® from 4-0hl®s ⁱ »^ S = 'Sä®tlJGr3, £ ä! Ai2 with e'twa 0.001 Gev9 (EaliimatkjlacaBt Eerstellirag
Aminmass © duveh Hieetaag of a fitaMlisieassd ^ el © alt gek®Biis5 © ielmet, that® stabilizes them! 8.B «ia © iaer quantity iros 0 _s 001 rock O ₉ f @ ©«% _f £ pjgls © g @ aß © r® up to 0.01 Geifl »böEOgeu to the 6roiaatie @ ii @ Asia Procedure aaoh agreement 3% dadiireli g3k © sfiiE @ i © lM9 "3 _g that de-distilled 4- * 0blor-2-atetl ^ flaBilim is mixed with © twa 0 _s KaXiutnäthylxanthate" ü! 3.-tN3.M F1KCK6 EHM.-IN9. a SSMB 909849 / U90 BAD ORIGINAL