DE3330947A1 - Tetraurethanediols and a process for the preparation thereof - Google Patents

Abstract

Tetraurethanediols of the general formula <IMAGE> in which n is 2, 4 or 6 based on methylenedi(phenylisocyanate) and unbranched even-numbered aliphatic diols are obtained by reacting a mixture of diurethanediol and hexaurethanediol methylenedi(phenylisocyanate) in a molar ratio of 1:2 to 4:1, or a mixture of diurethanediol and in a molar ratio of 3:1 to 8:1, in the presence of a urethanisation catalyst at 80-180 DEG C, and removing the tetraurethanediol from the resulting reaction product as a fraction which is soluble in hot methanol.

Description

BAYER AKTIENGESELLSCHAFT 5090 Leverkusen, Bayerwerk

Central area

Patents, trademarks and licenses GM / sche

Tetraurethane diols and a process for their preparation

The invention relates to tetraurethane diols of the general formula

X ^^^ ⁼ \ LH

where η = 2.4 or 6
and a method for their production

Oligourethane diols defined by W. Kern and K.J. Rauterkus, Makromolekulare Chemie 28 (1958) 221-235 became known. These are 0-ligomers from Hexamethylene diisocyanate and 1,4-butanediol.

The adduct of 1 mole of MDI (4,4'-diisocyanatodiphenylmethane) and 2 moles of 1,4-butanediol was obtained from G.R. Eiden, dissertation Mainz 1979 described.

Tetra-urethane diols of the formula given above have not yet become known.

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The reaction of, for example, 2 moles of MDI with 3 moles of butanediol results in homologous mixtures of oligourethanediols from which the pure tetraurethanediol cannot be separated .

Surprisingly, it has been found that pure tetraurethane diol can be obtained if diurethane diol is reacted with hexaureethane diol or with MDI in the presence of urethanization catalysts.

The invention relates to tetraurethane diols of the general formula

HO- (CH ₀ ) -o4cO-NH- ^ ~ \ -CH ₀ - ^ S-NH-COO (CH ₀ ) -O-Lh Zn L. \ - / ζ \ - / L η I

in the

η = 2.4 or 6 means.

The invention is also a

Process for the production of tetraurethane diols based on un-

MDI and branched even-numbered aliphatic diols, characterized in that a mixture of diurethanediol and hexaurethanediol in a molar ratio of 1: 2 to 4: 1 or of diurethanediol and MDI in a molar ratio of 3: 1 to 8: 1 in the presence of a urethanization catalyst at 80-180 C converts and from the reaction product obtained the tetraurethanediol than in hot. Separate methanol-soluble fraction ■.

Ethylene glycol 1,4-butanediol and 1,6-hexanedial can be used as diols. Isomer-free, pure 4,4'-diisocyanatodiphenylmethane _(is used as the diisocyanate.

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COPY I

Urethanization catalysts according to the invention can the catalysts customary to those skilled in the art are used in the production of polyurethanes, however care must be taken that trimerization reactions are excluded and / or grounded. . \ from this. The reason will be metal catalysts, like Snr compounds the tertiary 'amines preferred. Aminophenols and pyridine, as well as alkali salts of carboxylic acids and phenols, are not suitable.

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The reaction can be carried out in the presence or absence of solvents will. Preferred solvents are aromatic hydrocarbons or halogenated hydrocarbons. It is particularly preferred Toluene. The tetraurethane diol can be isolated by extracting the reaction mixture with hot methanol. While hexaurethanediol remain as an insoluble residue, the hot methanol extract contains Tetra- and di-urethanediol. The tetra-urethane diol precipitates on cooling, while the di-urethane diol in cold methanol remains in solution. Of course, the di-urethanediol can also first be removed from the reaction mixture by extraction with cold methanol separate and then by extraction with boiling. Methanol win the tetraurethanediol as a dissolved fraction. The extraction can e.g. B. be carried out in a Soxleth apparatus. Tetra-urethane diols are valuable building blocks in the production of all kinds of plastics.

Example 1:

The di-urethanediol from MDI and 1,4-butanediol was in the molar Ratio of 4: 1 (diol to MDI) implemented with MDI. 1.5 g diurethane diol were abs in 17o ml of toluene. Mostly dissolved at 9o C and 0.1 ml of dibutyltin dilate added. There were 0.22 g of MDI

dissolved in 15 ml of toluene was added dropwise. It was 2 hours at 90 ° C and then 8'h stirred at room temperature. The one after distilling off of the residue remaining from the toluene was admixed with methanol. In the cold dissolves diurethane diol and small amounts of tetraurethane diol. The portion insoluble in cold methanol became in methanol cooked. Hexaurethanediol remained undissolved. After cooling, the tetraurethanediol (0.4 g) precipitated from the filtrate.

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Example 2;

The procedure was initially "as in Example 1, but with tetrahydrofuran as a solvent at 5o C and in the absence of a catalyst. The reaction mixture obtained contains diurethane diol, Hexaurethanediol and higher oligomers.

This reaction mixture was dissolved in toluene with the addition of dibutyltin dilaurate Heated to 9o C for 18 hours. After the solvent had been stripped off, the residue could clearly be formed by gel chromatography can be detected by tetraurethanediol.

LeA 22 573

Claims (2)

Claims | Z 1.) Tetraurethanediols of the general formula HO- (CH ₂ J _n -OJ-CO-NH- ^ VCH ₂ - ^ ~ ^ -NH-CO-O- (CH ₂ ) _n -0 ■ in the η = 2.4 or 6 means. 2. A process for the preparation of tetraurethanediols based on MDI and unbranched even-numbered aliphatic diols according to claim 1, characterized in that a mixture of diurethanediol and hexaurethanediol in a molar ratio of 1: 2 to 4: 1 or of diurethanediol and MDI in a molar ratio of 3 : Reacts 1 to 8: 1 in the presence of a urethanization catalyst at 80-180 C and separates the tetraurethanediol as a fraction soluble in hot methanol from the reaction product obtained. LeA 22 573