NL1010175C2 - Process for the preparation of N-alkyl carbamoyl derivative. - Google Patents

Description

- 1 - PN 9662

PROCESS FOR PREPARATION OF 5 N-ALKYL CARBAMOYL DERIVATIVE

The invention relates to a process for the preparation of an N-alkylcarbamoyl derivative and in particular a blocked isocyanate. A blocked isocyanate is a compound containing an isocyanate and a blocking agent.

Checkered isocyanates are used in the preparation of polyurethanes and polyureas. A blocked isocyanate 15 can be stably mixed with a polyol at room temperature. As the temperature increases, the blocking agent cleaves from the isocyanate group so that the released isocyanate can react with the polyol present to form a polyurethane.

A process for the preparation of an N-alkyl carbamoyl derivative is described in DE-A-2712931. Herein, an isocyanate is contacted with caprolactam to form a caprolactam block-blocked isocyanate.

A drawback of the method described in DE-A-2712931 is that the reaction with the toxic isocyanate entails high risks.

The object of the invention is to provide a method which does not have the above-mentioned drawback.

This object is achieved in that an amine is contacted with a carbonic acid derivative, which derivative contains a hydrocarbon Bronsted acid with a pKa greater than 5.

In the method according to the invention no isocyanate is present in the reaction mixture.

1010175 - 2 -

An advantage of the method according to the invention is that a blocked isocyanate is formed in which no free isocyanate is present anymore.

Since the known reaction described in DE-A-2712931 does not proceed quantitatively, a small amount of free isocyanate remains in the reaction mixture. To decrease the vapor pressure of this free isocyanate, the isocyanate is often trimerized before increasing contact with lactam by temperature increase. This is mainly used for IPDI and HMDI. A further advantage and consequence of the fact that in the process according to the invention no free isocyanate is present in the reaction mixture is that the above-mentioned trimerization reaction can be dispensed with.

A further advantage of the method according to the invention is that it can prepare an N-alkylcarbamoyl derivative, the nitrogen of which is secondary and the derivative is lactam, oxime, imide or imidazole. These are compounds that cannot be manufactured by the known isocyanate route.

Bronsted acids with a pKa greater than 5 may be: Oximes such as acetoxime, butanone oxime, cyclohexanone oxime; phenols and enols as; phenol, m-cresol, o-chlorophenol, p-toluene thiol, ethyl acetoacetate; alcohols and amines such as di-n-butylamine, 2,2,2-trifluoroethanol, N-Nydroxyphthalamide, N, N-dimethylhydrazine, N-hydroxysuccinimide; Compounds containing a basic nitrogen atom such as N, N-diethylhydroxylamine, 2-hydroxypyridine, 3-hydroxypyridine, 4-hydroxypyridine, pyridine N-oxide, 8-hydroxyquinoline, 8-hydroxyquinaldine, 6-chloro-2-hydroxypyridine, 3-hydroxypyridine N -oxide, 1010175 - 3 - 2-mercaptopyridine, 3-methyl-1-phenyl-2-pyrazolin-5-one, 3-methyl-2-pyrazolin-5-one, N-phenylhydroxylamine, 2-diethylaminoethanol, N-ethyl -N-phenylethanolamine, 2-mercapto-1-methylimidazole; 1,3-dipolar compounds such as nitron III, nitron IV; other compounds such as dimethyl phosphite, caprolactam, the amide of acetic acid and hydroxylamine (acetohydroxamic acid), p-toluenesulfonamide, diethyl barbituric acid, thioglycolic acid, thioacetic acid, thiobenzoic acid, acetone phenylhydrazone, p-toluenesulfonic acid.

Although there is no upper limit on the pKa of the hydrocarbon Bronsted acid, the pKa is preferably less than 25. Above a pKa of 25, even at elevated temperature, the deblocking reaction proceeds too slowly to have any commercial significance.

Preferably, the Bronsted acid is a lactam, oxime, imide or imidazole. These Bronsted acids have the advantage that they split off at a relatively low temperature and are not toxic.

A carbonic acid derivative, which derivative contains a hydrocarbon Bronsted acid with a pKa greater than 5, is prepared according to a known method. A possible method for the preparation of the carbonic acid derivative is described in JP-A-42017832.

Contacting an amine with the carbonic acid derivative can be done in various ways. Preferably this is done by dissolving the carbonic acid derivative in a suitable first solvent. Suitable solvents are generally non-protic solvents such as esters, ethers and hydrocarbons. Then, the amine dissolved in a second solvent can be slowly added to the carbonic acid solution with continuous stirring. Second solvents are preferably also selected from the same group of non-protic solvents.

Preferably, the first and second solvents are the same.

After adding the dissolved amine, the mixture is stirred for some time, after which the N-alkylcarbamoyl derivative formed can be separated from the reaction mixture by known techniques.

The invention further relates to the use of a compound prepared according to the method according to the invention in the manufacture of a coating.

The invention is further elucidated hereinbelow by means of the following examples.

15

Example 1 0 °; 54.4 grams (0.2 mol) of carbonyl bis-caprolactam was dissolved in 200 ml of ethyl acetate at 78 ° C. 88 grams (0.1 mol) of 1,4-diamine butane dissolved in 20 ml of ethyl acetate were added dropwise over 20 minutes. A white suspension formed. After four hours, the reaction was stopped. The white product was isolated by filtration. The caprolactam present was removed by sublimation in the vacuum oven at 60 ° C. The product, a white solid, was obtained with an efficiency of 80%.

30 1010175 - 5 -

Example II

0 0 "

N

[V7 J, 75.6 grams (0.3 mol) carbonyl bis-caprolactam was dissolved in 200 ml ethyl acetate at 78 ° C. To this, 14.6 grams (0.1 mol) of tris- (2-amine-ethyl) amine dissolved in 20 ml of ethyl acetate were added dropwise over 20 minutes. The clear solution was stirred at 78 ° C overnight. The solution was washed 3 times with 250 ml of water (with a little NaCl) to remove the caprolactam. The solution was dried with NaSO 4. The NaSO 4 was removed by filtration and the ethyl acetate was removed using the rotary evaporator. The product turned out to be a colored oil and was obtained with an efficiency of 99%.

Example III

ch3 2. (CH ^ °

To 10 ml of dibutylamine (60 mmol), 2.5 grams (10 mmol) of carbonyl bis-caprolactam (CBC) was added at 160 ° C. This colored solution was stirred at 160 ° C overnight. Everything was cooled down. 150 ml of ethyl acetate were added to the solution. The solution was 1010175-6 - then extracted three times with 150 ml of water (buffer pH = 5). The ethyl acetate was removed with the rotary evaporator. It appears that dibutylamine was still present in the product. This was removed by distillation. The product was an oil. The purity was 80%. The return on CBC was 99%.

Example IV

151.2 grams (0.6 mol) of carbonyl bis-caprolactam were dissolved in 400 ml of ethyl acetate at 78 ° C. To this, 34.8 grams (0.3 mol) of 1,6-diamine hexane dissolved in 40 ml of ethyl acetate were added dropwise over 15 minutes. The clear solution was stirred at 78 ° C overnight. The solution was washed 4 times with 250 ml of water (with a little NaCl) to remove the caprolactam. The solution 20 was dried with NaSO 4. The NaSO 4 was removed by filtration and the ethyl acetate was removed using the rotary evaporator. After recrystallization in ethyl acetate, the product was obtained as a white solid with a yield of 85%.

25 1010175 - 7 -

Example V

0 0 <ύ / ^ μ, ιλ ο ο 5 252 grams (1.0 mol) of carbonyl bis-caprolactam were dissolved in 400 ml of ethyl acetate at 78 ° C. To this was added 75.1 grams (0.5 mol) of 1,8-diamine octane dissolved in 150 ml of ethyl acetate over 15 minutes. The clear solution was stirred at 78 ° C for two hours. The solution was washed 3 times with 500 ml of water (with a little NaCl) to remove the caprolactam. The clear solution was cooled to 5 ° C. The product crystallized out and was isolated by filtration (yield = 47%). The solution was concentrated to 100 ml. and cooled to 5 ° C. The product crystallized again (yield = 38%). The product was isolated by filtration. Then the solution was concentrated to 50 ml. The product crystallized out again and was isolated by filtration (yield = 6%)

The different batches were dried at 40 ° C and vacuum. The product appeared to be a white solid. The overall return was 91%.

25 '010175 - 8 -

Example ill ° NN / (CH2) 5 V yyoo CT ^ N '' Λ 0 ^ (CH2) 5 5 302.4 grams (1.2 mol) of carbonyl bis-caprolactam was dissolved in 400 ml of ethyl acetate at 78 ° C. To this, 69.3 grams (0.4 mol) of triaminononane dissolved in 100 ml of ethyl acetate were added dropwise over one hour. The reaction was monitored by TLC. After 3 hours, the clear solution was cooled to room temperature and extracted 4 times with 500 ml of water (with a little NaCl). Then the solution was dried with NaSO 4. The NaSO 4 was removed by filtration and the ethyl acetate was removed with the rotary evaporator. The product was dried at 75 ° C and vacuum. The product was obtained as a light colored oil pure in hands (yield = 99%).

1010175

Claims (4)

A process for the preparation of an N-alkylcarbamoyl derivative, characterized in that a 5 amine is contacted with a carbonic acid derivative, which derivative contains a Bronsted acid with a pKa greater than 5. Method according to claim 1, characterized in that the pKa is less than 25. A method according to claim 1 or 2, characterized in that the Bronsted acid is a lactam, oxime, imide or imidazole. 4. Use of a compound prepared by the process according to any one of claims 1-3 in the manufacture of a coating. 1010175 COOPERATION TREATY (PCT) REPORT ON NEWNESS RESEARCH OF INTERNATIONAL TYPE IDENTIFICATION OF NATIONAL APPLICATION Characteristic of the applicant or of the authorized representative 9662NL Dutch application no. Filing date 1010175 September 24, 1998 Priority date of the applicant (name) DSM NV international rype Granted by the International Research Authority (ISA) to the request for an examination of an international type No SN 31937 EN I. CLASSIFICATION OF THE SUBJECT (where different classifications are used, indicate all the classification symbols) According to the International Classification IIPCI Int. Cl. 6: C 07 D 223/10, C 08 G 18/80 II. FIELDS OF TECHNIQUE EXAMINED Minimum documentation examined Classification class | Clause symbols Int. Cl.6 C 07 D, C 08 G Documentation examined other than the minimum documentation to the extent that such documents are included in the areas investigated Hl. 1 1 NO RESEARCH POSSIBLE FOR CERTAIN CONCLUSIONS (Comments on Supplementary Sheet!! V · | 1 LACK OF UNIT OF INVENTION (Comments on Supplementary Sheet) ~ o rm PCT / ISA / JOKa) 07.1979