CS232188B1 - 2- (2,2,6,6-tetramethyl-4-piperidylamino) propanedioic acid dialkyl ester and its preparation - Google Patents

Abstract

The essence of the invention is a dialkyl ester of 2-(2,2,6,6-tetramethyl-4-piperidylamino)propanedioic acid of the formula I where R is a methyl or ethyl group. The essence of the invention is further a process for the preparation of the compound of formula I, which is characterized in that the dialkyl ester of 2-bromopropanedioic acid of formula II is treated in dry benzene or toluene at a temperature of 20 to 30 °C in the presence of triethylamine. The invention has application in polymer chemistry for the preparation of a polymerizable light stabilizer of polymers

Description

The essence of the invention is the dialkyl ester of 2-(2,2,6,6-tetramethyl-4-piperidylamino) propanedioic acid of formula I

RO.

C - C ₍ H - C NH

/1/

HC^N ^CH„ 4 u 4 where R is a methyl or ethyl group. The invention further provides a method for preparing a compound of formula I, which is characterized in that the dialkyl ester of 2-bromopropanedioic acid of formula II ^0<5ϊ ·0 - CH - C/^ ⁰ Z ¹¹ /

RO^ J _r ^X ° ^R where R is a methyl or ethyl group, reacts with 4-amino-2,2,6,6-tetramethylpiperidine of formula III

H in dry benzene or toluene at a temperature of 20 to 30 °C in the presence of triethylamine. The invention has application in polymer chemistry for the preparation of a polymerizable light stabilizer for polymers.

232 188

The invention relates to the dialkyl ester of 2-(2,2,6,6-tetramyl-4-piperidylamino)propanedioic acid and the method of its preparation.

Steric hindered amines are highly effective light stabilizers of polymers. They inhibit radical processes that occur during photooxidation of polymers. The disadvantage of low molecular weight compounds of this group is their considerable volatility and extractability, which causes their gradual loss from the useful polymer during processing itself, or later during storage, dry cleaning, or washing.

The present invention eliminates the above disadvantages. The essence of the invention is the dialkyl ester of 2-(2,2,6,6-tetramethyl-4-piperidylamino)propanedioic acid of formula I

/1/ where R is a methyl or ethyl group. The invention further provides a method for preparing a compound of formula I, which is characterized in that the dialkyl ester of 2-bromopropanedioic acid of formula II

G - CH - G X ‘ \

RO Br GR /11/ where R is a methyl or ethyl group, reacts with 4-amino-2,2,6,6-2 tetramethylpiperidine of formula III

NH,,

I

CH ₃

CřLj

232 188 /111/ in dry benzene or toluene at a temperature of 20 to 30 °C in the presence of triethylamine.

The advantage of the present invention is the preparation of a polymerizable light stabilizer of piperidine-type polymers, which allows for the significant elimination of the aforementioned shortcomings of low-molecular compounds of this group.

Example 1

A solution of 2.3907 g (0.01 mol) of 2-bromopropanedioic acid diethyl ester in 10 ml of dry benzene is slowly added dropwise to a solution of 1.5526 g (0.01 mol) of 4-amino-2,2,6,6-tetramethylpiperidine and 1.4 ml of triethylamine in 40 ml of dry benzene at a temperature of 20 °C with constant stirring. The reaction mixture is allowed to continue stirring at the same temperature for 24 h. The resulting solid is filtered off with suction, dissolved in a saturated solution of potassium carbonate and the solution is thoroughly extracted with ether. The benzene filtrate and ether extracts are combined, washed thoroughly with distilled water, dried with anhydrous sodium sulfate and the solvents are evaporated. 20 ml of petroleum ether is added to the sticky residue, whereupon it solidifies. After filtration, a yellowish, powdery substance is obtained, with a melting point of 93 to 96°C.

Elemental analysis for

Calculated: C = 61.32%, H = 9.62%, N = 8.94%

Found: C = 61.10%, H = 9.51%, N - 8.72%

IG spectrum (chloroform) ^max ^910,1030, 1080, 1150, 1175, 1235, 1295, 1380, 1440,

1460, 1575, 1650, 1730, 2820, 2970, 3370 cm” ¹

232 188

Example 2

To a solution of 1.56 g of 4-amino-2,2,6,6-tetramethylpiperidine and 1.4 ml of triethylamine in 20 ml of dry toluene at a temperature of 100 °C, a solution of 2.11 g of 2-bromopropanedioic acid dimethyl ester in 20 ml of dry toluene is added dropwise with constant stirring. The reaction mixture is stirred for 20 h and further worked up as in Example 1. A product with a melting point of 80 to 90 °C is obtained.

Example 3 * 36 g of polypropylene powder were homogenized with 0.72 g of the compound according to Example 1 and prepared by mixing in a plastograph.

Brabender and subsequent pressing of foils with a thickness of 0.2 mm, which were irradiated in a rotary irradiation device with a Tesla^JRW 125 W discharge lamp. The development of carbonyl groups in the unstabilized and stabilized foil was monitored. While the unstabilized foil reached a carbonyl index of 0.1 in 190 hours, the stabilized sample reached the same degree of degradation in 1100 hours.

The invention is used for the preparation of a polymer light stabilizer of polymers.

Claims (2)

Β B B D METHOD OF THE INVENTION 232 188 1. 2- (2,2 ', 6-tetramethyl-4-piperidylaraino) -propanedioic acid dialkyl ester of the formula I * S - C - CH 2 O 2 R 5, H "OR 1 H (1) wherein R is methyl or ethyl 2. A process for the preparation of a compound of formula I according to claim 1, characterized in that the dialkyl 2-bromo-pentanedioate of formula II is 0 C - GH - G / 1 RO Br OR * / 11 wherein R is methyl or ethyl. with 4-amino-2,2,6,6-tetramethylpiperidine of formula III h3g h3g gh3 GH3 in dry benzene or toluene at 20-30 ° C in the presence of triethylamine. / 111 /