CS226304B1 - Compounds of 2,2,6,6-tetramethyl-4-piperidylester of 15-(7,15-diazadispiro(5,1,5,3)hexadecyl)methylenebutandienic acid and method of praparing same - Google Patents

Description

The present invention relates to 2,2,6,6-tetramethyl-4-piperidyl 15- (7,15-diazadispiro), 1,5,33-hexadecyl / methylenebutanedioic acid, 1,2,2,6,6-pentamethyl-4-piperidyl ester 15- [7,15-diazadispiro [5,1,5,3] hexadecyl] methylenebutanedioic acid and a process for their preparation.

Said compounds belong to the group of sterically hindered amines which constitute a modern class of plastic light stabilizers, in particular polyolefins. Although the mechanism of their stabilizing action is not entirely clear, it is known from the literature that substances containing more than one active ingredient per molecule are much more effective than substances containing only one active ingredient. Similar compounds with one active ingredient are the subject of US Patent 3,992,351.

This disadvantage is overcome by the present invention. The present invention provides 15- [7,15-diazadispiro [5,1,5,3] hexadecyl] methylenebutanedioic acid 2,2,6,6-tetramethyl-4-piperidyl ester and 1,2,2,6,6-pentamethyl-4-piperidyl ester 15- (7,15-diazadispiro) 5,1,5,32-hexedecyl / methylenebutenedioic acid of formula I:

wherein R is a proton or a methyl group. The present invention further provides a process for the preparation of compounds of formula (I) which is characterized in that for dimethyl 15- [7,15-diazadispiro [5,1,5,3] hexadecyl] methylenebutanedioic acid dimethyl ester (II):

HN

COO-CH 3 λ I

N — CH, —CH (II)

CH ₂ -COO-CH ₃ is treated with 4-hydroxy-2,2,6,6-tetramethylpiperidine or methylpiperidine of formula III:

CHjCHj

4-hydroxy-1,2,6,6-pentanal N

OH (III) CH ₃ CH ₃ wherein R is a proton or a methyl group, higher-boiling hydrocarbons (100-160 DEG C.) in the presence of the transesterification catalyst.

The compounds of formula III can be used as light stabilizers for plastics, in particular polyolefins, containing three active ingredients, thereby increasing their effectiveness in the stabilization process.

Example 1

Preparation of 15- [7,15-Diazadispiro [eta] < 5 >, 1,3,3-hexadecyl / ethylenebutanedioic acid 2,2,6,6-tetramethyl-4-piperidyl ester.

A solution of 1 mole of 15- [7,15-diazadispiro [5,1,5,33-hexadecyl] methylenebutanedioic acid dimethyl ester and 2.5 mole of 4-hydroxy-2,2,6,6-tetramethylpiperidine in 2,000 ml of dried xylene is heated for 8 hours. hours at 150 ° C in the presence of a catalytic amount of lithium amide.

Nitrogen was bubbled through the reaction mixture. After cooling, the reaction mixture was washed with water and the xylene solution was dried with anhydrous sodium sulfate. After xylene was distilled off on a rotary vacuum evaporator, the crude product was purified by crystallization from petroleum ether. The product in the form of white crystals t. t. M.p. = 120-124 ° C was obtained in yield 67

Molecular weight analysis: 630.96 calculated: 70.63% C, found: 70.90% C,

H, 11.14; N, 8.87. H, 11.43; N, 9.10.

Example 2

Preparation of 15- [7,15-Diazadispiro [1,5,3] hexadecyl] methylenebutanedioic acid 1,2,2,6,6-pentamethyl-4-piperidyl ester.

A solution of 1 mole of 15- / 7,15-diazadispiro [5,1,5,3] hexadecyl / methylenebutanedioic acid dimethyl ester and 2.5 mole of 4-hydroxy-1,2,2,6,6-pentamethylpiperidine in 2000 ml of dried xylene is heated at 150 ° C for 8 hours in the presence of a catalytic amount of tetrapropylortotitanate. Nitrogen was bubbled through the reaction mixture. After cooling, the reaction mixture was washed with water and boiled with activated carbon. The xylene solution obtained by filtering off the activated carbon was dried with anhydrous sodium sulfate. The xylene was distilled off on a rotary evaporator to give the product as a pale yellow oil in 68% yield.

Analysis of Ο ^ ΗγθΝ ^ Ο molecular weight:

659.02 calculated:

71.28% C, 71.56% C,

H 10.71, H 10.91,

8.50 - N; 8.27% N.

Example 3

The polypropylene blend with 0.1% antioxidant content of 2,6-di-tert-butyl-4-methylphenol 0.15% calcium stearate content and 0.2% stabilizer content was stable for 18 hours at room temperature in di-chloromethane. After methylene chloride was distilled off on a rotary evaporator, the resulting powder was homogenized in a plastograph mixing chamber for 5 minutes at 200 ° C. Films 0.18 mm thick were pressed from the mixture at 190 ° C and a pressing time of 30 seconds. A control film was prepared by the same procedure, except that no stabilizer was added. The foils were irradiated with a 125 W mercury vapor lamp. Irradiation uniformity was achieved by rotating the samples around the radiation source.

The increase in carbonyl groups as a function of the irradiation time is a measure of the degradation of the polymer by UV radiation. The growth of the carbonyl groups was monitored using an i-spectrometer. The control foil without a light stabilizer achieve the increase of carbonyl groups, ^N, CO ~ to 750 hours. The film containing the light stabilizer prepared according to Example 1 reached ΔΑθθ = 0.15 after 3,400 hours, and with the light stabilizer prepared according to Example 2, the increase in carbonyl groups AA = 0.15 was achieved after 3000 hours.

Said compounds can be used as light stabilizers in polymers, especially polyolefins.

Claims (3)

Compounds of 15,6 / 7,15-diazadispiro [5,15,3] hexadecyl / methylenebutanedioic acid 2,2,6,6-tetramethyl-4-piperidyl ester of the formula I cH. CH. COO Λ / DB CH ₃ CH ₃ CH ₃ CH ₃ (I) CH ₂ -COO <NR wherein R is a proton or a methyl group. ch ₃ ch ₃ 2. A process for the preparation of compounds of formula (I) according to claim 1, characterized in that to the dimethyl ester of 15- / 7,15-diazadispiro [5,1,5,3] hexadecyl / methylenebutanedioic acid II coo-ch ₃ λ I ⁽ⁱⁱ⁾ HN N-CH ₂ -CH ₂ -coo-ch ₃ is treated with a 4-hydroxy-2,2,6,6-tetramethylpiperidine compound of the formula III ch ₃ ch ₃ R-N OH (III) CH ₃ CH ₃ wherein R is as defined in 1, 6 to 10 hours in a hydrocarbon solvent with a boiling point of 100 to 160 ° C in the presence of a re-esterification catalyst. 3. The method according to claim 2, wherein the reaction time is 8 hours and the reaction is carried out in a xylene solution at 150 ° C.