DD146464A1 - PROCESS FOR STABILIZING ORGANIC POLYMERES BY PHOSPHORIC ACID SEEDAMIDES - Google Patents

Abstract

The aim of the invention is a process for the stabilization of organic polymers by Phosphorigsäureesteramide against thermooxidative degradation. The inventive sterically hindered Phosphorigsäureesteramide have good color and hydrolysis and are effective both at lower (<100 degrees C) and at higher (> 150 degrees C) temperatures effectively. The compounds according to the invention correspond to the general formula (formula) in which X is O or NH and R &sub1;! R &sub2;! and R & ind3! are open-chain or cyclic, substituted or unsubstituted but in particular sterically hindered aliphatic or aromatic radicals.

Description

- * -. 216 57 6

Title of the invention

Process for stabilizing organic polymers by phosphorous acid ester amides

Fields of application of the invention

The invention relates to an improved process for the stabilization of organic polymers against oxidative, thermal, photochemical and hydrolytic degradation by ester amides of phosphorous acid. Furthermore, the compounds of the invention increase the stability of organic polymers to ozone and act as flame retardants -for organic polymers. Organic polymers are subject to high thermal stresses in the manufacturing process as well as deterioration in use by environmental factors such as temperature, light, oxygen, ozone, moisture, biological processes and others. Therefore, compounds are added to organic polymers that can prevent or retard one or more of these degradation processes.

For this reason, there is great practical and economic interest in developing such stabilizers which have the longest possible lifetime of organic polymers with the same performance properties. In this case, the most complex possible effect of the stabilizers is sought as light stabilizers, chain-terminating and preventive antioxidants in order to keep the content of the organic polymers as low as possible.

31.0M 19-79 * 820630

-2- 216 576

Characteristic of the known technical solutions

Phosphorous acid esters are known to be good thermal stabilizers for organic polymers. The activity of these classes of compounds is essentially attributed to their action as complexing agents, peroxide decomposers, chain terminators and also as light stabilizers.

In particular, sterically hindered esters of phosphorous acid show good activity, as described, for example, in US Pat. No. 3,415,906. Sterically hindered phosphites have a good activity especially at high temperatures (> 150 ⁰ G). Furthermore, organic phosphites having free amino groups are also used as additional functional groups as stabilizers of organic high polymers, in particular polyolefins, rubber and lubricating oils (US Pat. No. 4,006,117, DE-OS No. 2,656,999). Esteramides of phosphorous acid are also known as stabilizers for polyamides, rubber and lubricating oils (DE-OS 2 216 4-53, SU 1 799 18, SU 523 105). The use of these compounds brings but some disadvantages. Thus, the hydrosylation stability of these derivatives is very low and, especially in the presence of amino groups, a strong Bigenverfärbung of the polymer by the stabilizer. Thus, the use of these classes of compounds is limited to organic polymers, the application of which no requirements are made to FarbStabilität, such as rubber, lubricating oils, inter alia

Object of the invention

The object of the invention is an improved process for stabilizing organic polymers against thermo-oxidative degradation by oxygen or ozone.

Explanation of the essence of the invention

The present invention relates to a process for the stabilization of organic polymers by novel sterically hindered, hydrolysis-stable, non-discoloring. and low-volatile ester amides of phosphorous acid.

1657

According to the invention the object is achieved in that the organic polymers are added compounds corresponding to the general formulas I to rV;

P-Z

R ₂ O

Y P-Z

^ O ^

II

worm R "and

ο-

^l 6 » ^Rr ig and R.

10

III

Alkyl, phenyl, benzyl, Alky! Phenyl, aralkyl, cycloalkyl, G ₂ -C ₆ hydroxyalkyl or hydroxyphenyl in the formula I, and

Is hydrogen, C ₁ -C ₃ alkyl, cycloalkyl, phenyl, alkyl phenyl, aralkyl in the formula III, and

a radical consisting of the radicals of the formulas A and B in the formulas I and II,

- N '

Hydrogen, C ₁ -Cg alkyl ,. Cycloalkyl, phenyl, alkylphenyl, aralkyl in the formula A, and

Is hydrogen, C ₁ -Cg alkyl, cycloalkyl, phenyl, alkylphenyl, aralkyl in the formula A, and

are independently hydrogen C ₁ -Co alkyl, preferably methyl in the formula B, and

Hydroxy, amino, alkoxy, phenoxy and alkoxycarboxylic

216576

a bivalent radical consisting of the radicals of the formulas G, D, E and S ¹ means

ι -

-C-R

M 2 13

R

14 (G)

R ₁₁

* R

16 (D)

(E)

wherein

and

and

R ₄ O - CH ₂ CH ₂ -

NP CR _q O - CH ₂ CH ₂ -

and

(F)

independently hydrogen,

C ₁ -Cg are alkyl or C ₁ -C ₄ hydroxyalkyl, and

are independently hydrogen, C ₁ -Cg alkyl C ₁ -Cg hydroxy alleny 1, and

independently of one another are hydrogen, C ₁ -C 5 alkyl, C ₁ -C 5 cycloalkyl, aralkyl and alkylaryl in the formulas C, D and E.

Furthermore, according to the invention, organic polymers can be stabilized by adding compounds of the general formula IV;

where IL, and

- O

Hydrogen or

Alkyl is, and

_ 5 -

216 5 76

R ₀ C ^ -Gy, ο alkyl. Phenyl, benzyl, aralcyl or C _n - (

Alleylaryl means, and

Y is a bivalent radical consisting of the previously

described radicals G ₁ D and E.

Compounds of formula I are e.g.

Phosphorigsäuredibuty! Ester-di-tert-butyl-amide Phosphorigsäurediphenylesteranilid Phosphorigsäurediphenylester-N-hy ät lanilid Phosphorigsäurediphenylester-2, ^'i -l, 6-trimethylanilide Phosphorigsäurediphenylester-2,4,6-tri-tert-butylanilid Phosphorigsäurediphenylester dicyclohexylamide Phosphorigsäuredibutylesteranilid Phosphorigsäuredibutylesterpiperidid Phosphorigsäuredibutylester-4-benzoxy-2,2 ^f -6,6'-tetramethyl-

piperidide ·

Phosjjhorigsäurediphenylesterpiperidid Phosphorigsäurediphenylester-4-benzoxy-2,2 ^f -6,6'-tetramethy1 piperidide

Compounds of formula II are e.g.

2-di-tert-butylamino-benzo-1,3,2-dioxaphospholine 2-di-cyclohexylamino-benzo-i, 3,2-dioxaphospholine 2-anilino-benzo-1,3,2-dioxaphospholine 2-N- Äthylanilino-benzo-1,3,2-dioxaphospholin 2- ^(2,4,6-T rimethylanilino) -benzo-1,3,2-dioxaphospholin 2-piperidino-benzo-1,3,2-dioxaphospholin 2- (2 , 4,6-Trimethylperidino) benzo-1,3,2-dioxaphospholin 2- (M-Beηζoxy 2.2 ^f -6,6 tetramethyl piperidino) benzo-1,3,2-dioxaphospholin

2-0ctylamino-1,3,2-dioxaphospholane 2-Anilin0-1,3,2-dioxaphospholane 2- (2,4,6-Trimetli5 ^r lanilino) -1,3,2-dioxaphospholane 2-tert-butyl- Amino-5-dimetlay 1-1,3,2-dioxaphosphorinane 2-Anilino-5-dimethylethyl-1,3,3-dioxaphosphorinane 2- (2,4,6-tri-tert-butylanilino) -5-dimethoxy 1-1,3,2-dioxaphosphorinane

2 - (^ - 3ehzoxz / -2.2 -6.6 ^{f f} ~ tetra.niethylpiperidino) -5-dimethyl-1,3,2-dioxaühosOhorinan

_ ₆ _ 216 576

Compounds of formula III are e.g.

2,2 ^t -Anilino-di (benzo-1,3,2-dioxaphospholine) 2,2 ^f - (2,4,6-trimethylanilino) -di (-benzo-1,3,2-dioxaphospholine) 2, 2 ^f -Tert-butylaminodi (benzo-1,3 ', 2-dioxaphospholin) 2,2 ^f -p-phenylenediamino-di (benzo-1,3,2-dioxaphospholine) 2,2 ^f - Anilino-di (1,3,2-dioxaphospholane) 2,2 ^f - (2,4,6-trimethylanilino) -di (1,3,2-dioxaphospholane) 2,2 ^f -anilino-di (5-dimethyl-) 1,3,2-dioxaphosphorinane) 2,2 ^f - (2,4,6-trimethylanilino) -di- (5-dimethyl-1,3,3-dioxaphosphorinane)

Compounds of the general formula IV are, for example ^:

2- (2,6-di-tert-butyl-4-methylphenoxy) -1,3,2-diazaphospholane 2 ~ (phenoxy) -1,3,2-diazaphospholane 2-phenoxy-benzo-1,3 »2 -diazaphospholin

2- (2,6-di-tert-butyl-4-metnylphenoxy) -benzo-1,3,2-diazapliosphalan

The compounds of the formulas I to III or IV are prepared by reacting the corresponding phosphorous ester monochlorides (G) or dichlorides (H)

ROP _x ~ ° (G) (H) ^C1

obtained with the relevant amines. The Phosphorigsäureestermonochloride or dichlorides (G) and (H) are known or easily prepared by well-known methods. The reaction with the amines is carried out in the presence of a tertiary amine, such as triethylamine or pyridine zur'Neutralisation of the resulting hydrochloric acid. Particularly suitable solvents are diethyl ether, dioxane, dimethylformamide, tetrahydrofuran, methylene chloride, benzene, toluene or petroleum ether. The. The resulting amides of phosphorous acid are both solid and liquid. The purification of the liquid compounds is generally carried out by distillation in vacuo. Solid products are in particular recrystallized from alcohol, diethyl ether, benzene, hexane or cyclohexane.

216 5 76

  - 7 -

The compounds of formulas I to IV are used as stabilizers and flame retardants for organic monomers and polymers.

For example, such are:

1. Polyolefins, such as polyethylene, polypropylene, polyisobutylene, polybutene-1, polyisoprene, polybutadiene and polystyrene so; ie copolymers of the said homopolymers underlying monomers such as _o styrene-butadiene copolymers, propylene-isobutylene copolymers. "

2. Halogenhaltige vinyl polymers such as polyvinyl chloride, polychloroprene and chlorinated rubber

3. polyacrylates, polymethacrylates, polyacrylonitrile and their copolymers with other vinyl compounds such as acrylonitrile, butadiene, styrene

4. Polyvinyl alcohol, polyvinyl acetate

5 · Polyethylene oxide, polypropylene oxide and their copolymers

6. Polyurethanes and polyureas

7. polyamides and copolyamides derived from dicarboxylic acid diamides or lactams

8. Polyesters derived from dicarboxylic acids and dialcohols or lactones, e.g. polyethylene glycol terephthalate

9 »Phenol-formaldehyde and melamine-formaldehyde resins '10. Natural polymers such as cellulose, rubber and the like

11. Natural and synthetic organic polymers which are pure monomers or mixtures of such, for example mineral oils, oils, waxes and fats.

_v The compounds of the formulas I to IV are added to the substrates in a concentration of 0.005 to 5% by weight, calculated on the material to be stabilized. ,

21 65.7 6

Preference is given to 0.02 to 0.5 wt.% Of the compounds incorporated. The incorporation may be carried out, for example, by admixing at least one of the compounds of the formulas I to XV and, if appropriate, further additives, by methods customary in the art, before or during processing. The compounds of the formulas I to IV can also be added before or during the polymerization, it being possible to obtain by a possible incorporation into the polymer chain stabilized substrates in which the stabilizers are non-volatile or extractable.

The compounds of formulas I to IV can be used both alone and in combination with other known stabilizer classes, e.g. With:

1. Antioxidants, like

2,6-di-tert-butyl- ^z- methylphenol

2,5-di-tert-butyl-4-hydroquinone

2,2 ^f -Thiobis- (6-tert-butyl-4-methylphenol) 2,2 ^f -methylene-bis (6-tert-butyl-4-methylphenol) β- (3 »5-di-tert .-Butyl- ⁱ l-liydroxyphenyl) -propionsäureäthylester

3-Diethyl 5-di-tert-butyl-4-hydroxybenzylphosphonic acid

Phenyl-2-naphthylamine

2. Sunscreens, such as

2- (2'-IIydroxyphenyl) -benzotriazole 2,4-bis- (2'-hydroxyphenyl) -6-alkyl-s-triazine 2-hydroxybenzophenone

  Methyl o-cyano-.beta.-methyl-p-methoxycinnamate Nickel dibutyldithiocarbamate Bis (2,2,6,6-tetramethylpiperidyl) sebacate

3 · Preventive antioxidants, such as

HjlT'-diacetyl-adipic dihydrazide Mercaptobenzimidazole Lauryldithiopropionate Tri- (nonylphenyl) phosphite

-9- 216 5 76

The preparation and use of the compounds according to the invention are described in more detail in the following Examples The compounds shown were characterized by elemental analysis and NMR spectra.

Exemplary embodiments 1 to 5

According to the following general procedure, the compounds of general formula I listed in Table 1 are used

¹ ^ PZ shown.

R ₂ O

0.1 mol of the relevant Phosphorigsäuresiestermonochlorids are dissolved in 100 ml of dry toluene with exclusion of moisture and under nitrogen. The resulting solution is treated with a mixture of 0.1 mol of the corresponding amine and 0.1 mol of triethylamine or pyridine in 50 ml of toluene at a rate that the temperature of the reaction mixture does not exceed 40 ⁰ C.- After completion of the addition of the amine is the reaction mixture for 3 h at room temperature or, for sterically hindered amines at 70-80 ⁰ G stirred. The hydrochloride formed is filtered off and the filtrate is freed from the solvent. The residue is worked up by distillation in a high vacuum or by recrystallization.

Table 1 R ₁ -R ₂ Z Kp. / B ¹ P. ( ⁰ C) example No. " ^G 6 ^H 5 -NH (G ₆ H ₅ ) Ep ₇ 148 1 -C ₆ H ₅ -NH (COHO ₃ C ₆ H ₂ ; ) Fp. 126 (Ligroin) 2 -t C ₄ H _g -N (UC ₄ Hg) ₂ . Kp ₁ 128 3 -TC ₄ H ₉ -NH (C ₆ H ₅ ) Ep ₃ 133 4 "*" ^σ 4 ^Η 9 -piperidyl Ep ₆ 106- 08 5

- 21 6 5 76

Example 6 to 23

According to the following general procedure, the compounds listed in Table 2 of the general formula II

, P-Z shown.

0.1 mol of the cyclic Phosphorigsäureestermonochlor ids are dissolved under nitrogen and exclusion of moisture in 200 ml of dioxane. This solution is admixed with a mixture of 0.1 mol of the corresponding amine and 0.12 mol of triethylamine in 50 ml of dioxane (variant 1). Likewise, it is also possible to work without a tertiary amine if 0.22 mol of the relevant amine are used (Variant ß). The addition takes place at a rate that the temperature does not exceed 30 ⁰ G. Then heated for 3 h under reflux. ^The precipitate formed is filtered off and the filtrate is concentrated. The residue is worked up by distillation in a high vacuum or by recrystallization. ,

Example 24 to 26

In otherwise the same procedure as in Examples 6 to 23, 0.2 mol of the corresponding Phosphorigsäureestermonochlorids were reacted with 0.1 mol of a primary amine, wherein compounds of general formula III

^L 3

(III)

(Table 3). '

Table 3

Example Y R- Variant Fp./Kp. ( ⁰ C)

24E-C ₆ H ₅ ex Fp. ? 8

(Alcohol)

25 E -COH ₃ ) ₂ O ₆ H ₃ o (mp 134-36

'. (Alcohol)

26. E tO ₄ H _g . OC-E ¹ P. 34-35

Table 2

21 6576

Example no.

Varian- Fp./Kp. ( ⁰ C) te

Kp. _{0) 4} 79-80

10 e 1 NH (C ₈ H ₁₇ ) β Kp. 0.4 (R ₁₇ = H; -N (CH ₃ ) ₂ OC Kp. 0.4 108-109 6 e cC Kp. 0.8 102-3 7 e piperidyl oC Kp. 0.4 144 8th e 2,4,6-trimethylpiperidyl OC Mp. 72-74 11 e 4-hydroxy-2- _r 2,6,6-tetramethylpiperidyl ß Kp. 0.2 108-109 (Alcohol 12 e -NH (C ₆ H ₅ ) • ß Kp. 94 13 ^B -N (C ₂ H ₅ ) (C ₅ H ₅ ) ß Kp. 0.2 148-150 14 e -N (G ₆ H ₅ ) ₂ oC • Kp. 0.8 95-96 15 e -NH ((CHO) ₂ C ₆ Ho) oC Kp. 0.8 140 16 e NH (CgH ₁₇ ) oC Kp. 0.2 130-31 17 e -IM ^ KjrjiXf- J Q oC Mp. 102-05 18 e --N (C ₆ H ₅ ) (G ₂ H ₅ ) oC Kp. 0.2 131-32 19 0 E ₃ ) -NH (G ₈ H ₁₇ ) oC Kp. 0'6 103-05 20 G oC Kp. 0.7 48 21 G oC Kp. 108 22 (R ₁ C = R ₁₆ = C) ^B Mp. 120 23 F 92-93 (Ligroi

-12-. 21.6576

Example 27 to 31

In otherwise the same procedure as in Examples 6 to 23, 0.1 mol of phosphorous acid-2,6-di-tert-buty1-4-methylphenylesterdichlorid were reacted with 0.2 mol of the corresponding amide in the presence of triethylamine, wherein compounds of the general Formula XV

3 - P \ N - I R ₂ (IVa) or. 3 - P T N j (IVb) 1 (Table R ₁ educated become 4).

Table 4 "

Example R 1 R ₅ Y variable Kp./Pp. ( ⁰ C)

No. J '. , ante

2? -C ₆ H ₅ -C ₂ H ₅ -C ₂ H ₅ - ^ ^κ Ρ · o, 2

28 - (CH ₃ ) (C ₄ H ₂ O) ₂ C ₆ H ₂ -CgH ₁₇ -H - ° ( bp _{Q 8} 81-83

29 - (CH ₃ ) (C ₄ H _g ) ₂ C ₆ H ₂ -C ₆ H ₅ -C ₂ H ₅ - OC _Bp . _0j8 115-19

30 - (CH ₃ ) (C ₄ H ₉ ) ₂ C ₆ H ₂ -H-E <X mp 126-28

31 - (CH ₃ ) (C ₄ Hg) ₂ C ₅ H ₂ -H. - C <K mp 162-65

Example 32

Inhibition of autoxidation of tetralin

As a rapid test for determining the effectiveness of the compounds according to the invention as inhibitors of the autoxidation of organic polymers or monomers, the influence of these compounds on the AIBN-initiated oxidation of tetralin can be used.A measurement of the effectiveness of these compounds is the induction period, type and relative Autoxidation rate S after the induction period.

In an experimental apparatus, the oxidation of tetralin (0.667 mo1 / 1) in chlorobenzene at 60 ⁰ C, initiated by AIBN • (5 * 10 "- ^ mol / 1) in the presence of various Phosphorigsäureamide (5 x 10""mol / 1) examined.

For comparison, samples stabilized with triphenyl phosphite (TPP) and 2,6-di-tert-butyl-4-methylphenol (BHT) were used (Table 5).

Table 5

Example t _T -n / min

No. ¹ ^

without 0 1 TPP 10 0.82 BHT 260 1.02 7 30 0.22 15   415 0.26 16 780 0.10 18 540 0.14 25 250 0.09

Example 33

Inhibition of autoxidation of polypropylene

The oxygen uptake during the oxidation of isotactic polypropylene (MW 510,000, ash content 0.29 % \ titanium content 0.017%, aluminum content 0.11 % and atactic fraction 0.68 %) at 180 ⁰ G in the presence of phosphorous acid ester amides (0.05 mo IAg "or 0.025 mol / kg of polypropylene.) As a measure of the effectiveness of these compounds as antioxidants, the induction period tjp and the relative autoxidation rate S were used.

For comparison, samples stabilized with triphenyl phosphite (TPP) or 2,6-di-tert-butyl-4-methylphenol were considered (Table 6).

All amides, especially the aromatic derivatives have a pronounced induction period and a strong retardation effect.

- 21 6 5

Table 6

Example t _T -p / min S

No. ^{ir r}

without 40 1,00

TPP. 72 0.69

BHT 210 0.52

6. 180 - 0.56

7 220 0.76

8,149 0.81

9,162 0.67

11,180 0.62

12 148 0.67

15,285 0.76

16 230 0.67 18 200 0.54

21 280 0.68

22 310 0.73 25 294 0.68

30,215 0.61

31 230 * 0.55

Example 34

Stabilization of rubber SMR-5CV against ozone

To determine the effectiveness of antiozonants, the viscosity test of DEM ¹ IAJT was used. The change in viscosity of a solution of the rubber in chloroform (0.5 g SMR-5CV in 100 ml CHCl ₃ ) was monitored at a constant ozone concentration (0.5 mg Oo / min) as a function of the ozonization time. In general, a concentration of 1 mole of antiozonant per 1000 g of rubber was used. As a measure of the effectiveness of the stabilizers used as antiozonants the time defined (t _Q q f £ _o) ^ ^Θ * - ^ ^he a reduction in viscosity of the rubber solution of 10% occurs (Table 7).

216576

As a comparison, the results were recorded with the known antiozonant Η, Ν-dimethyl-p-phenylenediamine (DiIPDA).

Table 7

Example without. DMPDA 6 15 16 18

No.

^t o, 9 ^t 2o ^{/ min 2 45 15 38 30} ^ ²

Claims (5)

216576 claims of the invention 1. A process for preparing stabilized organic polymers containing compounds of general formula I, R ₂ O P-Z (I) wherein and R _{2 is} C ₁ -O ₂ ^, alkyl, phenyl, benzyl, alkylphenyl, aralkyl, cycloalkyl, C ₂ -C ₄ hydroxyalkyl or hydroxyphenyl, and a residue consisting of the radicals of the formulas A and B R ₆ R (A) - N> - R _ft (B), rr 9
in which R 1 is hydrogen, C ₁ -C 6 -alkyl, cycloalkyl, phenyl, Alkylphenyl, aralkyl in the formula A., and R _{5 is} hydrogen, C ₁ -C ₃ alkyl, cycloalkyl, phenyl, Alkylphenyl, aralkyl in the formula A, and Rg, Rr ₇ , Rq independently of one another are hydrogen C ₁ -Cg alkyl, and R _{10 are} preferably methyl in formula B, and Ro hydroxy, amino, alkoxy, phenoxy or alkoxycarboxylic is bonyl, or Contain compounds of general formula II, worm
Y a divalent radical consisting of the radicals of the formulas G, D, E and F, -C-H. -C - (C) R. cr- ^R i2 ^ R. 16 R 13 in which
R "and R, R ₁₁ , and CH ₀ - (F) independently hydrogen, al kyl, cycloalkyl, phenyl, alkylphenyl, aralkyl in the formula F, and are independently hydrogen, C ₁ -alkyl, C ₁ -C ₆ hydroxyalkyl, and g independently of one another are hydrogen, C ₁ -C ¹ , C ₁ -Cg hydroxyalkyl, and and R ₁₈ independently of one another hydrogen, C ₁ - kyl, Ct - Cg are cycloalkyl, aralkyl and alkylaryl in the formulas C, D and E, Al al al wherein
Z a radical consisting of the radicals of the formulas A and B - n: , R ₁ ^ R ₁ R _{8 is} (B) -.- Λί- 214 576 in which R and R r independently of one another are hydrogen, C 1 -C 6 alkyl, cycloalkyl, phenyl, alkylphenyl, aralkyl in the formula A, and independently of one another hydrogen, C 1 -C 6 -alkyl and R ^ q is preferably methyl in formula B, and R is hydroxy, amino, alkoxy, phenoxy or alkoxycarbonyl, or. Contain compounds of general formula III, O JO- X P-N-P X (III) VA ₃ V Eo is hydrogen, C 1 -C ₈ alkyl, O-C ₆ cycloalkyl,
Phenyl, allyl phenyl, Ar alkyl, and Y is a divalent radical consisting of the radicals of the formulas C, D and E according to claim 2, or compounds of general formula IV, X POR ₃ (IV) Hydrogen, C ^ -O ₈ alkyl, and Hydrogen, C 1 -C 6 -alkyl, cycloalkyl, phenyl,
Alky! Phenyl, aralkyl, and A divalent radical consisting of the radicals of the formula C and E according to claim 2. "C ι © ^ / υ 2. A process for stabilizing organic polymers with compounds of general formulas I to XV according to claim 1 as antioxidant, antiozonate, light stabilizer and flame retardant · " Process for the stabilization of organic polymers by addition of compounds of general formulas I to IV according to claim 1 alone or in combination with other chain-terminating and preventive antioxidants and light stabilizers." 4-e method of stabilizing organic material, such as e.g. Polyolefins, especially polypropylene, polyisoprene, polybutadiene; Polyvinyl halides, in particular "polyvinyl chloride; polyester alcohols, for example polyethylene glycol terephthalate; polyamides; polyurethanes and natural and synthetic polymers, such as gums, mineral oils, waxes and fats, by adding compounds of general formulas I to IV according to claim 1, in a concentration of from 0.005 to 5 wt.%, Preferably 0.02 to 0.5 Gevv.%, Calculated on the material to be stabilized.