CS254699B1 - 4- (2,3-epoxypropoxy) -2,2,6,6-tetramethylpiperidine-1-oxyl and its preparation - Google Patents

Abstract

The solution concerns 4-(2,3-epoxypropoxy)-2,-2,6,6-tetramethylpiperidine-1-oxyl of the formula I and the method of its preparation, which consists in reacting 2,2,6,6-tetramethyl-4--hydroxypiperidine-1-oxyl of the formula II with epichlorohydrin under intensive mixing in a heterophase system, one phase being formed by an aqueous solution of alkaline hydroxide and types of phase is formed by an organic solvent that does not initiate with the aqueous phase in the presence of a catalyst of the type of onium salts in the temperature range of 10 to 100 °C. The compound of the formula I is used as a light and thermal oxidation stabilizer for polymers and for the preparation of polymer light stabilizers by polyaddition and copolyaddition reactions, for the preparation of polyethers, copolyethers, polyesters and copolyesters, or enables the binding of the stabilizer molecule to suitable groups on the polymer chain.

Description

The invention relates to 4- (2,3-epoxyoxypropoxy) -2,2,6,6-tetramethylpiperidine-1-oxyl and a process for its preparation.

Stably nitroxyl radicals based on sterically hindered amine derivatives have wide application. Gradually they have found importance in biochemistry as spiiif probes and labels [L. J. Berliner, Spin Labeling, Theory and Applications. Academic Press, New York, 1976], in the field of pharmaceutical chemistry IN. M. Emanuel, N. P. Kovatova, R. F. Dyachkoivskaya, L. K. Denisova, Antibiotiki (Moscow), 27, 811 (1982)], in cigarette filter drunks [British-American Tobacco Cc., Cnd. Pat. no. 1,070,587 (1980)) and others. In addition, stably nitroxyl radicals effectively inhibit thermo-oxidative degradation of various polymers [Μ. B. Nejinan, Aging and Stabilization and Polimers, Nauka, Moscow, 1964, G. Scott, Developments in Polymer StabilisatiOin-7, ed. G, Scott. Elsevier Applied Science Publishers, London, 1984, Chap. 2] and also exhibit excellent photostabilization capabilities [A. B. Sbapiro et al., Vysokomol. Soedin., 12, 2373 (1973).

These include 6-membered cyclom nude compounds such as derivatives

2,2,6,6-tetraalkylpiperidine-1-oxy, 2,2,6,6-tetraalkylpiperazine-1-oxy, or 7,15-diazadispiro [5,1,3,3] liexadecan-7-oxy.

The compound of the present invention contains a reactive epoxide group in addition to a functionally hindered nitroxyl group in its molecule. The presence of this group in the molecule allows the preparation of polymers and copolymers with functional nitroxyl groups in the side chain by polyaddition and copolyaddition reactions, preparation of polyethers, copolyethers, polyesters and copolyesters, as well as coupling of a compound of the invention to suitable functional groups on chains of different polymers. This compound has not been previously described in the literature.

The present invention provides 4- (2,3-epoxypropoxy) -2,2,6,6-tetramethylpiperidine-1-oxyl (I).

O-N

A

CM, o,;

C * i i Cle, ó - nyo -1. h -1 r- »- c f-? ₀ / t. X yd

G

The invention further provides a process for the preparation of a compound of formula I, characterized in that 2,2,6,6-tetramethyl-4-hydroxypiperidine-1-oxyl of formula II is reacted with epichlorohydrin under vigorous stirring in a heterophasic system, one phase forming an aqueous solution an alkali hydroxide, preferably sodium hydroxide in a concentration range of 5 to 50% or potassium hydroxide in a concentration range of 5 to 70%, and forms a second base. an organic solvent not mixed with a scientific phase, such as benzene, toluene or xylenes, in the presence of an onium salt type catalyst such as tetrabutylammonium chloride, tetrabutylammonium bromide. tetrabutylammonium hydro, gesulfate or tetrabutylphosphonium bromide, which is used in an amount of 1 to 10 mol% for the amount of compound II in a temperature range of 10 to 100 degrees Celsius.

Example 1

8.61 g (0.05 mol) of 2,2,6,6-tetramethyl-3-hydroxypiperidin-1-oxyl, 1.61 g (0.005 mol) of tetrabutylammonium bromide, 23 g (0.26 mol) of epichlorohydrin, 20 ml of benzene and 20 ml of 50% aqueous sodium hydroxide solution are stirred vigorously at room temperature for 24 hours. The organic layer was separated, washed with water and brine, and dried over anhydrous sodium sulfate. The solvent and excess epichlorohydrin were distilled off in a vacuum evaporator to give a red liquid which was vacuum distilled. A fraction of red liquid is collected at a temperature range of 120 to 125 ° C at 0.11 kPa. Yield: 7.4 g of pure product. j. 64.8% of theoretical yield.

Elemental analysis for:

C12H22NOS calculated:

% C, 63.13;% H, 9.71;% N, 6.14.

H, 10.31; N, 5.94.

Example 2

8.61 g (0.05 mol of 2,2,6,6-tetramethyl-4-hydroxypiperidin-1-oxyl), 0.85 g (0.0025 mol of tetrabutylammonium hydrogen sulfate), 11.5 g (0.125 mol) of epichlorohydrin, 20 g ml of toluene and 20 ml of a 30% aqueous potassium hydroxide solution are vigorously stirred at 60 DEG C. for 8 hours, and the reaction mixture is worked up as in Example 1. The yield is 8.2 g of pure product, i.e. 71.8%. of theoretical extract.

Example 3

8.61 g (0.05 mol) of 2,2,6,6-tetramethyl-4-hydroxypiperidin-1-oxyl, 0.34 g (0.001 mol J of tetrabutylphosphonium bromide, 5.55 g (0.06 mol)) epichlorohydrin, 10 ml of a mixture of xylenes with a distillation range of 137 to 140 ° C and 20 ml of a 60% aqueous potassium hydroxide solution are stirred vigorously at 100 ° C for 6 hours. The yield is 86 g of pure product, ie 7 ¹ · 3% of the theoretical yield.

Example 4

100 parts by weight of unstable powdered polypropylene are impregnated in dichloromethane with 0.1 wt. parts of 2,6-di-tert-butyl-4-ylphenol, 0.15 wt., calcium stearate and 0.1 wt. After evaporation of the solvent, 0.2 mm thick sheets are pressed from the mixture at 20 MPa at 190 ^DEG C. for 5 minutes. The foils are irradiated with a 125 W Mercury lamp at 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 220 hours, the stabilized polymer does not reach this value until 1050 hours.

Example 5

100 parts by weight of unstabilized powdered polypropylene are impregnated in dichloromethane with 0.1 wt. After evaporation of the solvent, 0.5 mm thick films are pressed from the mixture at 20 MPa and heated at 200 ^DEG C. for 5 minutes. Strips of 5 x 40 mm are cut from the sheets thus prepared and placed in open tubes of 6 mm in diameter and allowed to heat stress at 130 ° C. The samples are periodically tested by bending the foil, the exposure time at which the sample breaks is referred to as the end of the induction period. While the unstabilized sample has an induction period of 2 days, the stabilized sample has an induction period of 62 days.

Claims (5)

at 80 ° C for 8 hours. The reaction mixture is worked up as in Example 1. Yield 8.2 g of pure product, i.e. 71.8% of theory. Example 3 3.61 g (0.05 mol) of 2,2,6,6-tetramethyl-4-hydroxypiperidine-1-oxyl, 0.34 g (0.001 mol of tetrabutylphosphonium bromide, 5, 55 [mu] g (0.06 mol) of epichlorohydrin, 10 ml of a xylene mixture with a 137 to 140 [deg.] C. range and 20 ml of a 60% aqueous potassium hydroxide solution are stirred vigorously at 100 [deg.] C. for 6 hours. the parent mixture is treated in the same manner as in Example 1. The yield is 86 g of pure product, i.e. 71% of the theoretical yield Example 4 100 parts by weight of unstable powdered polypropylene is impregnated with dichloromethane with 0.1 part by weight of 2,6-diterc of butyl stearate and 0.1 wt.% of calcium stearate and 0.1 wt.% of the compound prepared according to Example 1. After evaporation of the solvent, films having a thickness of 0.2 mm at a pressure of 20 DEG C. are pressed from the mixture. MPa and heat 190 CC for 5 minutes The films are irradiated with a 125 W arc lamp at a distance of 7 cm from the source. The polymerization is monitored by developing a carbonyl band in the infra-red spectra. While a carbonyl index of 0.2 for pure polypropylene is 220 hours, stabilized polymer reaches this value after 1050 hours. Example 5 100 weight parts of a destabilized powdered polypropylene are impregnated in dichloromethane with 0.1 wt. Compound prepared according to Example 1. After evaporation of the solvent, the mixture was compressed. 0.5 mm thick at 20 MPa and 200 CC for 5 minutes. Strips of 5 x 40 mm are cut out of the films thus prepared and placed in open tubes of 6 mm diameter and allowed to heat at 130 ° C. The samples are periodically tested by bending the foil, the exposure time at which the beacon is referred to as the end of the induction period. While the unstabilized sample has induction! period of 2 days, stabilized sample induction! period of 62 days. 1. The 4- (2,3-epoxypropoxy) -2,2,6,6-tetramethylpiperidine-1-oxyl of formula (I). CH, Cl-L / v -.- / CH, Obj, f i. 2. A process for preparing 4- (2,3-epoxypropoxy) -2,2,6,6-tetramethylpiperidine-1-oxyl of the formula I according to claim 1, wherein the 2,2,6,6-tetramethyl- 4-hydroxypiperidine-1-oxyl of formula II CW-G ° g (ii) reacts with epichlorohydrin under intensive mixing in a heterophasic system, forming a one-phase aqueous alkaline solution. and the type of phase forms water-immiscible organic solvents in the presence of union salt catalysts at a temperature range of 10 to 100 ° C. 3. A process according to 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. A process according to claim 2, wherein benzene, toluene or a mixture of xylenes is used as the aqueous phase-immiscible organic solvent. 5. A process according to claim 2, wherein the reaction catalyst used is a salt, preferably tetrabutylammonium chloride, tetrabutylammonium bromide, tetrabulamylammonium hydrogen sulfate or tetrabutyl phosphonium bromide in an amount of 1 to 10 mol% based on 2.2.6. 6-tetramethyl-4-hydroxypiperidine-1-oxyl.