CS220996B1 - Polymerizable diester-based light stabilizers of propanedioic acid and tetrasubstituted piperazines and processes for their preparation - Google Patents

Abstract

The invention relates to polymerizable light stabilizers based on diesters of substituted propanedioic acid and tetrasubstituted piperazines and a method for their preparation. (The essence of the method for preparing light stabilizers consists in treating tetrasubstituted piperazine with a dialkyl ester of 2-halogenopropadiic acid in dry dimethylformamide or in a dry organic solvent in the presence of toacetate. The substances prepared according to the invention are used as light stabilizers of polymers.

Description

The invention relates to polymer-based light staibilisators based on diesters of substituted propanedioic acid and tetrasubstituted piperazines and a process for their preparation.

(The principle of preparing light stabilizers is to treat the tetra-substituted piperazine with a 2-halo-propanedioic acid dialkyl ester in dry dimethylformamide or in a dry organic solvent in the presence of a toase.

The substances prepared according to the invention are used as light stabilizers of polymers.

220998

The present invention relates to six-substituted propanedioic acid comprising a tetrasubstituted piperazine unit moiety in its molecule having the following general formula:

where

R is a methyl or a style group and the invention further relates to a process for their preparation.

The process for the preparation of polymerizable light stabilizers based on diesters of substituted propanedioic acid and tetrasubstituted propanedioic acid and tetrasubstituted piperazines is based on the reaction of a compound of formula

with dimethyl or diethyl 2-halopropanedioate in dry dimethylformamide, or in a dry hydrocarbon, solvent (e.g. benzene, toluene, xylene) in the presence of a base such as triethylamine, pyridine, etc.

Said compounds belonging to the group of spherically hindered amines can themselves act as light stabilizers of polymers. A disadvantage of the low molecular weight compounds of this group is their considerable volatility and drastability from the useful polymer. The preparation of polymeric light stabilizers can eliminate these drawbacks. The substances which are the subject of the invention may serve for this purpose.

Example 1

To a solution of 2.22 g (0.01 mol) of 7,15-diazadispirp (6, l, 5, 3) of hexadecane in 20 ml of anhydrous dimethylformamide was at room temperature while ¹ was slowly added dropwise a solution of 2.30 g ( 2-Bromo-propanedioic acid diethyl ether in 10 ml of anhydrous dimethylformamide was stirred for 5 hours, then poured into 60 ml of water and basified strongly with 410% sodium hydroxide solution. The residue is recrystallized from ethanol to give the product in the form of a white crystalline solid, mp = 103-165 ° C.

Elemental analysis for C21H36N2O4 ·: Calculated:

C 66.218%, H 9.54%, N 7.36%, Found:

C 66.98% II 9.61%, N 7.52%. Example 2

To a solution of 6.66 g (0.03 mol) 7.15 g-diazadispiro (5.1,1.3) ihexadecane and 0.5 ml triethylamine in 1.20 ml dry benzene was slowly stirred at room temperature with stirring A solution of 7.17 g (0.03 mol) of 2-bromopropanedioic acid diethyl ester is added dropwise. The reaction mixture is allowed to stir at room temperature for 24 h. The resulting solid is filtered off with suction, dissolved in saturated potassium carbonate solution and extracted thoroughly. The ether extracts were combined with the filtrate, dried over anhydrous sodium sulfate and the solvents were evaporated and the residue was recrystallized from ethanol to give the product as a white crystalline solid, mp = 164-167 ° C. C21H36N2O4: Calculated:

C 66, -28%, H 9.54%, N 7.36%. found:

C 66.53%, H 9.70%, N 7.49%.

IR (chloroform):

^ max

850, 9: 210 ,, 1045, 1035, 1145, 120-5, 1: 230, 1.285, 13 (315, 1360, li3®5 ·, 1450, 16710, 1720-, 2930 cm ^-1 '

1 _H- NMR spectrum (denatured chloroform):

WITH -

1.25 (triplet, 6H);

1.45 (broad band, 2OH),

2.218 (singlet, 4Hj,

3.14 (broad band, 1 H),

4.22 (quartet, 4H), ppm.

Claims (2)

SUBJECT 1. The polymerizable light stabilizers substituted diester] ^- of a propándioveij, fetrasubstituovaných piperazines OF THE INVENTION according to claim 1, characterized in that to a compound of the formula R is methyl or ethyl. 2. A process for the preparation of polymerizable light stabilizers based on diesters of substituted propanedioic acid and is then treated at room temperature with dimethyl or diethyl ester of 2-halopropanedioic acid in a dry organic solvent, preferably dimethylformamide, benzene, toluene, in the presence of a base, preferably triethylamine.