DE1270046B - Process for the preparation of polyalkylene glycol ether-containing primary aromatic amines - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. CL:

German class:

Number:
File number:
Registration date:
Display day:

C07c

C08g

12q-5
39C-6

P 12 70 046.8-42
January 22, 1965
June 12, 1968

It is known to convert aromatic isocyanates into primary amines. This happens e.g. B. by Hydrolysis with acids or bases. However, this reaction is very imperfect, because that Amine formed during hydrolysis reacts with unreacted isocyanate to form urea. This side reaction cannot be prevented even by using excess strong mineral acid suppress.

It has now been found that polyalkylene glycol ether-containing primary aromatic amines can be used obtained when reaction products of aromatic di- or triisocyanates with polyalkylene glycol ethers or polyalkylene glycol thioethers, preferably those with molecular weights between 400 and 4000, in a known manner with secondary or tertiary carbinols and then optionally in the presence of acids as catalysts in an inert solvent subject to thermal cleavage.

Examples of suitable aromatic isocyanates are: Phenyl, tolyl, naphthyl, anthracenyl di and triisocyanates, Diphenylmethane diisocyanates, triphenylmethane triisocyanates. As a polyalkylene glycol ether or Polyalkylene glycol thioethers are preferably those with molecular weights between 400 and 4000 into consideration.

Secondary or tertiary carbinols for the purposes of this invention are compounds of the general formula

dd / -> ITKj

<T> 2

where R ^{1 is} hydrogen or an alkyl radical, R ² and R ^{3 are} individually alkyl or aryl radicals and together with the carbon atom connecting them are a 5- or 6-membered unsaturated or saturated hydrocarbon ring, in this ring also carbon atoms through heteroatoms, such as nitrogen, sulfur and oxygen, can be replaced, furthermore R ^{2 can} also be hydrogen.

Examples of suitable carbinols are: trimethylcarbinol, dimethylphenylcarbinol, methyldiphenylcarbinol, ' l-methylcyclohexanol, 1-methylcyclopentanol, u-methylbenz alcohol, sec-butanol, cyclohexanol.

From the reaction products of aromatic di- or triisocyanates with polyalkylene glycol ethers or polyalkylene glycol thioethers and the carbinols, the process for the preparation of
Polyalkylene glycol ether containing primary
aromatic amines

Applicant:

Paint factories Bayer Aktiengesellschaft,

5090 Leverkusen

Named as inventor:

Dr. Wolfgang Heydkamp,

Dr. Erwin Müller, 5090 Leverkusen;

Dr. Dr. H. c. Dr. e. H. Otto Bayer,

5673 Burscheid

Carbamic acid ester produced. This is done according to a method known per se by the Reaction products and the tertiary carbinols in approximately stoichiometric amounts in an inert Reacts solvent.

Suitable solvents for carrying out the 1st as well as the 2nd stage of the process are aliphatic hydrocarbons having boiling points above 12O ⁰ C, z. B. high-boiling petroleum ethers and aromatic, optionally chlorinated or nitrated hydrocarbons, such as benzene, toluene, xylene, chlorobenzene, dichlorobenzene and nitrobenzene, are suitable.

Acids suitable as catalysts are, for. B. Mineral acids and their acidic salts, such as hydrogen chloride, Sulfuric acid or sodium hydrogen sulfate, organic sulfonic acids such as p-toluenesulfonic acid, and halogenated aliphatic carboxylic acids such as chloroacetic or bromoacetic acid. In general using trihaloacetic acid, e.g. B. trichloroacetic acid. This acid is acidic enough to to catalyze the cleavage reaction and on the other hand forms with the released aromatic amine the corresponding ammonium trichloroacetate. This compound disintegrates quantitatively at higher temperatures in chloroform and free amine. When this acid is used as a catalyst, the removal is thus possible the catalyst from the reaction product is particularly simple. Furthermore, Lewis acids, such as B. boron trifluoride etherate can be used. the

809 559 499

The amount of acid added can be between 1% of the stoichiometric amount up to a multiple excess, z. B. three times the excess, the stoichiometric amount.

The 1st step of the process according to the invention is usually carried out by dissolving the reaction product and the carbinol in any of the above solvent, to temperatures between about 50 and 14O ⁰ C, generally from 80 and 12O ⁰ C, keeps for some time. The reaction time is between 10 minutes and 5 hours. The ester formed in solution of the components can be prepared by adding the acid and by re-heating to temperatures between 40 and 170 ° C, generally 70 to 150 ⁰ C, saponification to the amine. The end of this reaction can be recognized by the cessation of gas evolution. Generally this reaction takes between 15 minutes and 6 hours. Sometimes saponification is also possible at even lower temperatures down to about 0 ° C. In this way of carrying out the process, the amine formed can, if a sufficient amount of acid is used, immediately precipitate as a salt of the acid used as a catalyst.

It is of course also possible to use the intermediate compound, namely the carbamic acid ester, to isolate and saponify in a separate operation. In this case it can be advantageous to use a different solvent in the 1st stage than in the 2nd stage. Finally, you can get through Adding a base, e.g. B. alkali carbonate, ammonia or alkali hydroxide in aqueous solution at the end the saponification reaction and subsequent work-up of the organic phase, the amine in its Gain base shape.

The amines synthesized by the process according to the invention are starting materials for the isocyanate polyaddition process, excellent elastomers are obtained both in the spray process and in the casting process.

• Example 1

a) To 495 g of polypropylene glycol ether having a molecular weight of 1,975 g after thorough dewatering 87.5 2,4-tolylene diisocyanate were added and stirring continued for 2 ¹ I ₂ hours at 130 ⁰ C; the isocyanate content was 3.63%. 37.5 g of distilled water are added at 75 ° C. tert-butanol and heated for a further 2 hours, with 125 ° C should be reached for at least 1 hour without reflux of alcohol being observed. Free isocyanate can then no longer be detected.

b) The entire di-tert-butylcarbamic acid ester (620 g) was taken up in 1.01 of toluene and added to about 60 ° C with 86 g of p-toluenesulfonic acid added. at A steady elimination of gas began, which after 3 hours at 110.degree. C. 20.951 increased in temperature CCV isobutylene mixture (94% of theory) made up. To the cooled reaction mixture were 28 g of KOH in 0.51 of water are added, the aqueous phase is separated off and the organic phase is repeated several times washed with water. The polyamine freed from the solvent was a dark brown viscous oil from Molecular weight 2400 (calculated 2267). The molecular weight determination was carried out by analyzing the aromatic amine end groups by means of perchloric acid titration in glacial acetic acid. Yield: 97% of theory.

Example 2

As in Example 1, 620 g of bis-tert-butyl urethane were prepared, dissolved in 0.5 1 of chlorobenzene, and 73 g of boron trifluorodietherate in 0.251 of chlorobenzene were added at room temperature. Above 40 ⁰ C rapid elimination of gas took place; at a ^{final temperature of 125 °} C., over 95% of theory of gas was obtained in the course of 2 hours.

The dark red reaction product was treated with excess aqueous ammonia and washed with water. After drying, a brown-red viscous UI of molecular weight remained 2210 (calculated 2267), determined via end group analysis.

Example 3

(. Bp to 140 ¹ C) with 620 g of di-tert.-butyl urethane of Example 1 dissolved in 0.51 petroleum ether cleavage was purified by 65 g of anhydrous sodium hydrogen sulfate at 100 to 140 ° C completed; Gas yield over 85% of theory.

Working up was carried out by washing out the inorganic salts with water; the brown viscous Reaction product showed the molecular weight around 3350, determined by the content of amino end groups. Due to the high cleavage temperature, the chain was lengthened at the same time via urea groupings.

Example 4

Again, 620 g of di-tert.-butyl urethane of Example 1 were after preparation at 40 C ^for cooled and treated with 164 g of trichloroacetic acid. During the heating process, gas was slowly split off from 100 C; ^C to 148 C something had cleaved 90% of the theoretically calculated gas volume during 2 ^l k hours. The reaction product was brown and highly viscous. Molecular weight determinations by end group analysis showed values around 3200, so here too a simultaneous chain lengthening. It was possible to isolate 98.5 g (83% of theory) of split off chloroform.

Example 5

A prepolymer bearing NCO end groups and an NCO content of 6.33% is prepared in a known manner from a bifunctional, dehydrated polypropylene glycol ether and tolylene diisocyanate (2,4). After adding 90.0 g of α-methylbenzyl alcohol to 475 g of the prepolymer, the reaction is held for 2 hours at 110.degree. C., then diluted with 0.501 chlorobenzene and set below 50 ^; C 124 g techn. p-toluenesulfonic acid too. When heating is above 60 ° C a vigorous evolution of gas after 2 hours to 115 ⁼ C results in 95.6% of theory of gas. By adding 41.5 g of KOH in 250 ml of water, quantitative neutralization to p-toluenesulfonate is achieved, the organic phase is separated off, the solvent and the styrene obtained are removed and dried for 30 minutes at 110 ^: C / 0.2 mm. The light brown, medium viscosity oil shows an NH number of 67.2 in the end group analysis, which corresponds to the molecular weight of 1670.

Claims (1)

Claim: Process for the preparation of primary aromatic containing polyalkylene glycol ethers Amines, characterized in that the reaction products of aromatic Di- or triisocyanates with polyalkylene glycol ethers or polyalkylene glycol thioethers, preferably those with molecular weights between 400 and 4000, which are known per se Way with secondary or tertiary carbinols and then optionally in Presence of acids as catalysts in an inert solvent of a thermal Subjects to split. Considered publications:
Houben-Weyl, Methods of Organic Chemie, Vol. XI / 1, 1957, pp. 948 to 952; Vol. VIII, 1952, pp. 131, 141 to 143;
Helvetica Chimica Acta, 44, 540 (1961);
Journal of the American Chemical Society, 79, 98 (1957).