DE1066582B - - Google Patents

Description

GERMAN

PATENT OFFICE

kl. 12 ο 26/03

INTERNATIONAL KL.

C 07f; C 08g

ILf _n [λ Mt -Ζ - / - ·

F 26941 IVb / 12 ο

REGISTRATION DATE: OCTOBER 31, 1958

NOTICE
THE REGISTRATION
AND ISSUE OF THE
EDITORIAL: OCTOBER 8, 1959

It is known that isocyanates can be produced from primary amines by reaction with phosgene. It has now been found that a new class of silicon-containing isocyanates can be obtained easily and in good yield by using monomeric or polymeric silicic acid esters or silanol ethers containing primary amino groups, which have the group - O - R - (NHj) ₁ , where χ an integer and R denotes an organic radical, contained once or several times in the molecule bonded to silicon, reacted with phosgene in a manner known per se.

The smooth formation of isocyanates from these amino groups containing monomeric or polymeric silicic acid esters or silanol ethers is surprising as it is known is that carboxylic acid chlorides with silicic acid esters with splitting of the SiO bond and formation of Carboxylic acid esters react (Journ. Org. Chem., 7, p. 528, 1942). There react z. B. acetyl chloride and orthosilicic acid tetraethyl ester in the following way:

Si (OC ₂ H _B ) ₄ + CH ₃ -COCl > ^ao

> ClSi (OC ₂ Hg) ₃ + CH ₃ -COOC ^ H ₅

It was not foreseeable that such a reaction would take place with the acid chloride of carbonic acid, the Phosgene does not take place, but that the isocyanate is formed in a smooth reaction. As a starting material Serving, primary amino groups containing monomeric silicic acid esters or silanol ethers are, for example Compounds of the following formulas:

Process for the production of silicon-containing isocyanates

Applicant:

Paint factories Bayer Aktiengesellschaft, Leverkusen-Bayerwerk

Dr. Hans Holtschmidt, Cologne-Stammheim, and Dr. Dr. H. c. Dr. e. H. Dr. H. c. Otto Bayer,

Leverkusen-Bayerwerk have been named as the inventor

(CH,) _a Si / - O -

(CHg) ₃ Si-O-

nh

-NH,

NH

Si ίο

(1) CH ₂ = CH - Si (OCH ₂ - CH ₂ NH ₂ ) ₃

CH,

Si (OCH ₂ - CH ₂ - NH ₂ J ₂
CH ₃

(CHg) ₃ -Si-OCH ₂ -CH ₂ NH ₂
CH _a /

(2)

(3)

CH, - C - O.

CH, - C - O

CH.

; Si (O -CH ₂ - CH ₂ NH ₂ ) ₂ (10)

CH,

CH, - C - Si - \ 0 - CH, - CH, - CH - NH ₉

CH,

CHo-Si / —O -

NH,

(4)

(5)

CH,

NH.

As polymeric silicic acid esters or silanol ethers (organopolysiloxanes), which primary aromatic or ali-

909 637/420

Have phatic-bonded amino groups are, for example Connections of the following type called:

OR '

H ₂ NRO- Si

OR '

- O - Si -

OR '

R '

H ₂ NR-O-Si
R '

OR '

_0 - Si - OR - NH. Those obtainable by the present process Isocyanates are valuable starting materials for the production of plastics, e.g. B. by the isocyanate polyaddition process.

OR '

R '

O - Si R '

OR '
R '

0-Si-ORNH ₂ R '

272 g ( ^{1 line} ₂
o-cresyl ester

example 1
Mole) orthosilicic acid-tetrakis-p-amino-

Si / O

R denotes an organic aromatic or aliphatic radical, χ an integer corresponding to the molecular size of the polymer. It is easily possible to also use high-polymer silicic acid esters or organopolysiloxanes, e.g. B. those with a molecular weight of 50,000 and more to be subjected to the process according to the invention, provided that sufficient solubility in a solvent is ensured during the phosgenation.

Monomeric or polymeric silicic acid esters or silanol ethers containing amino groups are z. B. by transesterification of the corresponding silicic acid esters and alkoxysilanols at elevated temperatures with primary Amino alcohols and phenols, e.g. B. with ß-aminoethyl alcohol, (5-aminobutyl alcohol, y-aminobutyl alcohol, m-aminophenol or 4-aminocyclohexanol, light and accessible in good yields.

The phosgenation of the monomeric or polymeric silicic acid esters having primary amino groups or silanol ether is carried out in a manner known per se using the customary technical methods of phosgenation, z. B. by a cold phase-hot phase phosgenation, or by the hydrochloride process, the corresponding amino hydrochloride being phosgenated. It can be continuous or discontinuous are carried out, preferably using an inert solvent, such as Chlorobenzene, o-dichlorobenzene or nitrobenzene. Particularly In the case of higher molecular weight starting materials, it is desirable to work in the solvent. To achieve For a good yield, it is advisable, especially in the case of the aliphatic silicic acid esters, to adjust the temperature not to be chosen too high in the phosgenation. For this reason, the cold phase-hot phase phosgenation is usually used To be preferred to the hydrochloride process, since in the former case the mixture of carbamic acid chloride and amine hydrochloride is obtained in such a fine suspension that the hot phase phosgenation is completed in a short time at temperatures between 60 and 90 ° C. The inventive Process allows the production of isocyanates with one, two, three and more NCO groups depending on selected output connection. The isocyanates obtained can, for. B. by distillation or recrystallization getting cleaned. Many undistillable isocyanates are obtained in such a pure form that that a special cleaning is unnecessary. Briefly heating the reaction mixture in a vacuum below the boiling point or blowing out with an inert gas at an elevated temperature for destruction Any carbamic acid chlorides still present or to remove excess phosgene is sufficient completely off.

(produced by transesterification of tetraethyl silicate with p-amino-o-cresol) are dissolved in 3 liters of dry chlorobenzene. Subsequently, until saturation Hydrochloric acid initiated. It turns out a light crystalline precipitate, which is the hydrochloride of the corresponding Represents tetramine. Phosgene is then passed into the suspension of the hydrochloride at 110.degree. To After introducing phosgene for the last hour, the total amount has gone into solution. It is 2 hours with nitrogen blown to drive off the excess phosgene. Then it is clarified over dry activated charcoal and the chlorobenzene is distilled off in vacuo. The isocyanate of the formula remains as a brownish oil

NCO ^

Yield: 85% of theory.

Analysis for C ₃₂ H ₂₄ O ₈ N ₄ S. MW 620.6.

Calculated ... C 61.8%, H 3.89%, N 9.0%, Si 4.5%; Found ... C 61.2%, H 4.03 ° / ₀ , N 8.5%, Si 4.7 ° / ₀ .

Example 2

264 grams (1 mole) of the compound
CH ₃
Si / o

CH ₉

(produced by transesterification of m-aminophenol with dimethyl-dibutoxysilane) are converted into a solution at 0 ° C added dropwise of 700 g of phosgene in 3 l of chlorobenzene. Then after 12 hours of standing overnight Phosgenated with slow heating and at a maximum temperature of 110 ° C for 6 hours until everything has gone into solution. The isocyanate of the formula remains in a yield of 84% of theory

(CH ₃ ) ₂ -Si

_Bp . 0i05 150 to 155 ° C.

Example 3

360 g (0.5 mol) of a dimethyl polysiloxane with an average molecular weight of 720 and the general formula

NH.

O-

CH,

CH,

- Si - O

CH,

.-NH,

which was obtained by transesterification of dibutoxy-dimethylpolysiloxane with m-amino-o-cresol phosgenated by vigorous stirring for 4 hours at 120 ° C. and then worked up in the usual way. It a thinly viscous oil remains.

NCO number: calculated 9 <»/ ₀ , found 9.5%.

Claims (1)

Claim: Process for the preparation of süiciumhaltigen isocyanates, characterized in that one primary amino groups containing monomers or ίο polymeric silicic acid esters or silanol ethers which contain the group - O - R - (NH ₂ ) _x , where χ is an integer and R is an organic radical, bonded to silicon once or several times in the molecule, in a manner known per se with phosgene implements.