CS259397B1 - 2,2,6,6-tetramethyl-4-alyloxypiperidine and method of its preparation - Google Patents

Abstract

The solution relates to 2,2,6,6-tetramethyl-4-allyloxypiperidine of formula I and a process for its preparation, which is to leave it react 2,2,6,6-tetramethyl-4-hydroxypipe> - the ridine of formula II with allyl bromide is intense mixing in the heterophasic system, wherein one phase is an aqueous solution The alkali hydroxide and the species phase form organic solvent immiscible with aqueous phase in the presence of a catalyst of the anionic salt type in the 10 ° C range to 100 ° C. The compound of formula I is of use as a light stabilizer for polymers a for the preparation of polymeric light stabilizers polymerization of an unsaturated group, or by copolymerization with other unsaturated ones monomers.

Description

The invention relates to 2,2,6,6-tetramethyl-4-allyloxypiperidine and to a process for its preparation.

Sterically shielded amines are currently among the most effective light stabilizers for polymers [F. E. Karrer, Makromol. Chem., 181, 595 (1980), F. Gugumus, Developments in Polymer Stabilization-1, ed. G. Scott, Applied Science Publishers, London, 1979, Chap. 8, J. J. Usilton, A.R. Patel, Am. Chem. Soc. Polym. Prep., 18 (1), 393 (1977)].

These are various derivatives of 2,2,6,6-tetraalkylpiperidine, 1,2,2,6,6-pentaalkylpiperidine,

2,2,6,6-tetraalkylpiperazine or 7,15-diazadispiro [5,1,5,3] hexadecane. These compounds inhibit undesirable degradation processes that occur in the interaction of light and oxygen with polymers. The disadvantage of this class of light stabilizers is the high volatility and extractability of low molecular weight derivatives from polymers. The compound of the invention contains a functional unsaturation in its molecule. The presence of this group in the light stabilizer molecule allows the preparation of high molecular weight light stabilizers by polymerizing an allyl group or copolymerizing it with other unsaturated monomers. This compound does not shave so far as described in the literature.

The present invention provides 2,2,6,6-tetramethyl-4-allyloxypiperidine of formula I.

The present invention further provides a process for the preparation of a compound of formula I, characterized in that 2,2,6,6-tetramethyl-4-hydroxypiperidine of formula II

reacts with allyl bromide with vigorous stirring in a heterophasic system, one phase forming an aqueous solution of alkaline hydroxide, preferably sodium hydroxide in a concentration range of 5 to 50% or potassium hydroxide in a concentration range of 5 to 70%, and the other phases forming an organic solvent by aqueous gravity, such as benzene, toluene, or xylenes, in the presence of an onium salt type catalyst such as tetrabutylammonium chloride, tetrabutylammonium bromide, tetrabutylammonium hydrogen sulphate or tetrabutylphosphonium bromide, which is used in an amount of 1 to 10 mol. % of the amount of compound II in the temperature range of 10 to 100 ° C.

Example 1

4.68 g (0.03 mol) of 2,2,6,6-tetramethyl-4-hydroxypiperidine, 3.99 g (0.033 mol) of allyl bromide, 1.93 g (0.006 mol) of tetrabutylammonium bromide, 10 ml of benzene and 15 ml of benzene; ml of 50% aqueous sodium hydroxide solution is stirred vigorously at room temperature for 24 hours.

The organic layer was then separated, washed with water and brine, and dried over anhydrous sodium sulfate. The solvent was distilled off and the product was distilled under vacuum. A colorless liquid fraction is collected at a temperature interval of 125 to 130 ° C at a pressure of 933 Pa. 3.61 g of product are obtained, m.p. j. 61% of the theoretical yield.

Elemental analysis for Ο ₁₂ Η ₂ 3 _; ΝΟ: Calculated:

% C, 73.04;% H, 11.75;% N, 7.10.

H, 11.52; H, 6.96.

NMR (CDC1 _3):

<S (ppm)

0.98 (s, - CH ₃ and x, 6H);

1.00 (s, —CH ₃ eq, 6H),

1.22 to 1.95 (m, -CH ₂ -, 4H);

3.25 to 3.83 (m, -O-CH, 1H),

3.92 (d, -O-CH _{2 R} -, 2H);

4.67 to 5.35 (m, CH = _CH2, 2H);

5.42 to 6.22 (m, - CH = CH _2, 1H).

Example 2

4.68 g (0.03 mol of 2,2,6,6-tetramethyl-4-hydroxypiperidine), 3.99 g (0.033 mol of allyl bromide, 0.51 g (0.0015 mol of tetrabutylammonium hydrogen sulphate), 10 ml of toluene and 15 ml of 30% The reaction mixture was worked up as in Example 1. The yield was 4.22 g of product, i.e. 71.3% of theory.

Example 3

4.68 g (0.03 mol) 2,2,6,6-tetramethyl-4259397

-hydroxypiperidine, 3.99 g (0.033 mol) of allyl bromide, 0.17 g (0.0005 mol) of tetrabutylphosphonium bromide, 10 ml of a mixture of xylenes with a distillation range of 137 to 140 ° C and 15 ml of a 60% aqueous potassium hydroxide solution Stir vigorously at 100 ° C / 4 hours. The reaction mixture was worked up as in Example 1. 4.60 g of product were obtained, m.p. ]. 77.6% of the theoretical yield.

Example 4

100 parts by weight of unstabilized powdered polypropylene are impregnated in dichloromethane with 0.1 wt. diet 2,6-di-tert-butyl-4-methylphenol, 0.15 wt. % of calcium stearate and 0.2 wt. After evaporation of the solvent, 0.2 mm thick sheets are pressed from the mixture at 20 MPa at 190 ° C for 5 minutes. The films thus prepared are irradiated with a 125 W mercury lamp at a distance of 7 cm from the source.

The degradation of the polymer is monitored by the development of the carbonyl band in the infrared spectra. While the time of reaching the carbonyl index of 0.2 for pure polypropylene is 240 hours, the stabilized polymer does not reach this value until 1680 hours.

Claims (5)

1. 2,2,6,6-Tetramethyl-4-allyloxypiperidine of formula I. C H. CHG CH, (I) 2. A process for the preparation of 2,2,6,6-tetramethyl-4-allyloxypiperidine of the formula I according to claim 1, characterized in that 2,2,6,6-tetramethyl-4-hydroxypiperidine of the formula II (li) is reacted with allyl bromide with vigorous stirring in a heterophasic system, one phase forming an aqueous solution of alkaline hydroxide and the other phase forming an organic phase solvent immiscible with the aqueous phase, in the presence of an onium salt type catalyst in the temperature range of 10 to 100 ° C. 3. The process of claim 2 wherein the alkali hydroxide is sodium hydroxide in a concentration range of 5 to 50% or potassium hydroxide in a concentration range of 5 to 70%. 4. The process of claim 2 wherein benzene, toluene or xylenes are used as the organic solvent immiscible with the aqueous phase. 5. The process of claim 2, wherein the reaction catalyst used is an onium salt of tetrabutylammonium chloride, tetrabutylammonium bromide, tetrabutylammonium hydrogen sulphate or tetrabutylphosphonium bromide in an amount of 1 to 10 moles. pen. based on the amount of compound 2,2,6,6-tetramethyl-4-hydroxypiperidine.