STERICALLY HINDERED AMINES

Abstract

An intermediate of the formula (I)

##STR00001##

wherein the radicals R.sub.1 are independently of one another methyl, ethyl or n-propyl, is suitable for preparing a compound of the formula (A)

##STR00002##

wherein X is a group of the formula (A-I) or (A-II),

##STR00003##

Y is C.sub.11-C.sub.17alkyl, and
Z is a direct bond, (CH.sub.2).sub.8 or CH.sub.2SCH.sub.2.

The compounds of the formula (A) are useful for stabilizing an organic material against thermal, oxidative or light induced degradation.

Claims

1. An intermediate of formula (I) ##STR00020## wherein the radicals R.sub.1 are independently of one another methyl, ethyl or n-propyl.

2. The intermediate according to claim 1, wherein R.sub.1 is n-propyl.

3. A process for the preparation of an intermediate of formula (I) ##STR00021## wherein R.sub.1 is methyl, ethyl or n-propyl; which comprises reacting a compound of formula (I-a) ##STR00022## with ammonia in an organic solvent in the presence of hydrogen and platinum as hydrogenation catalyst.

4. The process according to claim 3, wherein the organic solvent is a C.sub.1-C.sub.4alcohol or a (C.sub.1-C.sub.4alkyl) ester and the reaction is carried out under a hydrogen pressure of 1 to 60 bar and at a temperature of 20 to 120 C.

5. The process according to claim 3, wherein the molar ratio of ammonia to the compound of the formula (I-a) is 0.5/2 to 1.3/2.

6. A compound of formula (A) ##STR00023## wherein X is a group of formula (A-I) or (A-II), ##STR00024## where Y is C.sub.11-C.sub.17alkyl, Z is a direct bond, (CH.sub.2).sub.8 or CH.sub.2SCH.sub.2, and the radicals R.sub.1 are independently of one another methyl, ethyl or n-propyl.

7. The compound according to claim 6, wherein X is a group of the formula (A-I).

8. The compound according to claim 6, wherein X is a group of the formula (A-II).

9. The compound according to claim 6, wherein R.sub.1 is n-propyl.

10. The compound according to claim 6, which corresponds to ##STR00025##

11. A composition containing a) an organic material and b) a compound of the formula (A) as defined in claim 6.

12. A composition according to claim 11, wherein the organic material is a polyolefin homo- or copolymer.

13. A composition according to claim 11, which additionally contains a conventional additive.

14. A method for stabilizing an organic material against degradation induced by light, heat or oxidation, which comprises incorporating a compound of the formula (A) as defined in claim 6 into the organic material.

Description

EXAMPLE I-1: PREPARATION OF THE INTERMEDIATE OF THE FORMULA (I-1)

[0164] ##STR00010##

[0165] In a steel autoclave 600 g of 1-propoxy-2,2,6,6-tetramethyl-piperidin-4-one in 1000 ml of methanol are slowly added to 230 ml of methanolic ammonia (10% solution in methanol) and 12 g of Pt-catalyst (5% on C) under 60 C./10 bar hydrogen atmosphere. After 16 h of hydrogenation, 12 g of Pt-catalyst and 50 g of 1-propoxy-2,2,6,6-tetramethyl-piperidin-4-one are added and further hydrogenated for 21 h. After filtration of the catalyst and removal of the solvent from the filtrate, 575 g of grey crystals are obtained. The crude product is recrystallized from 500 ml of methanol. The desired intermediate is obtained in form of colorless crystals.

[0166] Yield: 68.7% of theory

[0167] Melting point: 67-69 C.

[0168] Mass Spectroscopy (Chemical Ionization) (=MS (CI)): 412 (MH+)

EXAMPLE I-2: PREPARATION OF THE INTERMEDIATE OF THE FORMULA (I-2)

[0169] ##STR00011##

[0170] The intermediate is prepared from 1-ethoxy-2,2,6,6-tetramethyl-piperidin-4-one and ammonia in analogy to EXAMPLE I-1. After recrystallization of the crude product from methanol, the desired intermediate is obtained in the form of off-white crystals.

[0171] Yield: 63.1%

[0172] Melting point: 104-106 C.

[0173] MS (CI): 384 (MH.sup.+)

EXAMPLE I-3: PREPARATION OF THE INTERMEDIATE OF THE FORMULA (I-3)

[0174] ##STR00012##

[0175] The intermediate is prepared from 1-methoxy-2,2,6,6-tetramethyl-piperidin-4-one in analogy to EXAMPLE I-1. After recrystallization of the crude product from methanol, the desired intermediate is obtained in the form of off-white crystals.

[0176] Yield: 53%

[0177] Melting point: 74-76 C.

[0178] MS (CI): 356 (MH.sup.+)

EXAMPLE A-1: PREPARATION OF THE COMPOUND OF THE FORMULA (A-1)

[0179] ##STR00013##

[0180] 26 g (77 mmol) of stearoyl chloride is added at 0-5 C. to a solution of 30.4 g (74 mmol) of the intermediate (I-1), 9.32 g of triethylamine, 90 mg of 4-dimethylaminopyridine in 370 ml of toluene. The filtrate of this reaction mixture is extracted with water, saturated sodium bicarbonate and water. After standard work-up of the organic phase (drying and removal of the solvent at the rotary evaporator), the desired compound is obtained as an amorphous yellowish solid.

[0181] Yield: 44.8 g (89.6% of theory)

[0182] IR(neat): 1650 (Amide I)

[0183] MS(CI): 678 (MH.sup.+)

EXAMPLE A-2: PREPARATION OF THE COMPOUND OF THE FORMULA (A-2)

[0184] ##STR00014##

[0185] N,N-bis(1-propoxy-2,2,6,6-tetramethylpiperidine-4-yl)lauric acid amide is prepared from lauroyl chloride and the intermediate (I-1) in analogy to Example A-1. The desired compound is obtained as a yellow viscous oil.

[0186] Yield: 93.5%

[0187] IR (neat): 1649 (Amide I)

[0188] MS (CI): 594 (MH.sup.+)

EXAMPLE A-3: PREPARATION OF THE COMPOUND OF THE FORMULA (A-3)

[0189] ##STR00015##

[0190] N,N-bis(1-ethoxy-2,2,6,6-tetramethylpiperidine-4-yl)stearic acid amide is prepared from stearoyl chloride and the intermediate (1-2) in analogy to EXAMPLE (A-1). After purification by flash chromatography on silicagel (eluent hexane/ethyl acetate 5:1) the desired compound is obtained as a yellowish amorphous solid.

[0191] Yield: 100%

[0192] IR (neat): 1649 (Amide I)

[0193] MS (CI): 650 (MH.sup.+)

EXAMPLE A-4: PREPARATION OF THE COMPOUND OF THE FORMULA (A-4)

[0194] ##STR00016##

[0195] N,N-bis(1-methoxy-2,2,6,6-tetramethylpiperidine-4-yl)stearic acid is prepared from stearoyl chloride and the intermediate (A-3) in analogy to EXAMPLE (A-1). After purification by flash chromatography on silicagel (eluent hexane/ethyl acetate 4:1), the desired compound is obtained as a yellowish oil.

[0196] Yield: 72.7%

[0197] IR (neat): 1650 (Amide I)

[0198] MS (CI): 622 (MH.sup.+)

EXAMPLE A-5: PREPARATION OF THE COMPOUND OF THE FORMULA (A-5)

[0199] ##STR00017##

[0200] N,N,N,N-Tetrakis(1-propoxy-2,2,6,6-tetramethylpiperidine-4-yl)sebacic acid diamide is prepared from 26.52 mmol of sebacic acid dichloride and 50.52 mmol of the intermediate (I-1) in analogy to Example (A-1) (solvent methylene chloride). The desired compound is obtained as an amorphous solid.

[0201] Yield: 94.7%.

[0202] Melting point: 68-75 C.

[0203] IR (neat): 16476 (Amide I)

[0204] MS (CI): 990 (MH.sup.+).

EXAMPLE A-6: PREPARATION OF THE COMPOUND OF THE FORMULA (A-6)

[0205] ##STR00018##

[0206] N,N,N,N-Tetrakis(1-propoxy-2,2,6,6-tetramethylpiperidine-4-yl)oxamide is prepared from oxalyl chloride and the intermediate (A-1) in analogy to EXAMPLE (A-5). After recrystallization from methanol, the desired compound is obtained as a colorless solid.

[0207] Yield: 78%

[0208] Melting point: 249-250 C.

[0209] IR (neat): 1654, 1637 (Amide I)

[0210] MS (CI): 977 (MH.sup.+)

EXAMPLE A-7: PREPARATION OF THE COMPOUND OF THE FORMULA (A-7)

[0211] ##STR00019##

[0212] N,N,N,N-Tetrakis(1-propoxy-2,2,6,6-tetramethylpiperidine-4-yl)-thiodiglycollic acid diamide is prepared from thiodiglycollic acid dichloride and the intermediate (A-1) in analogy to EXAMPLE (A-5). After purification by flash chromatography on silicagel (eluent hexane/ethyl acetate 1:1) the desired compound is obtained as an amorphous yellowish solid.

[0213] Yield: 77.6%

[0214] Melting point: 90-96 C.

[0215] IR (neat): 1643 (Amide I)

[0216] MS (CI): 938 MH.sup.+

EXAMPLE B: STABILIZATION OF ETHYLENE/PROPYLENE/DIENE ELASTOMER (EPDM)

[0217] One part of the stabilizer indicated in Table 1 is incorporated into an EPDM based formulation containing the following components:

[0218] 100 parts by weight of EPDM,

[0219] 1 part by weight of stearic acid,

[0220] 5 parts by weight of ZnO,

[0221] 3.4 parts by weight of polyethylene glycol,

[0222] 60 parts by weight of paraffin oil,

[0223] 90 parts by weight of kaolin,

[0224] 180 parts by weight of chalk,

[0225] 1 part by weight of sulfur,

[0226] 2.5 parts by weight of N-cyclohexyl-2-benzothiazole sulfenamide,

[0227] 1 part by weight of Zn dibutyl dithiophosphate.

[0228] The formulation is treated on a two-roll mill at 120 C. for 5 minutes.

[0229] From the formulation obtained, 2 mm thick samples are prepared in a press at 175 C. and 180 bar with 10 minutes curing time.

[0230] The obtained samples are weathered according to ISO 4892-2 with dry cycle only. The formation of cracks and the level of chalking are optically assessed with a magnifying glass.

[0231] The results are listed in the following table.

TABLE-US-00001 TABLE 1 Stabilizer Chalking Cracks None Strong chalking 2 Compound of EXAMPLE A-1 No chalking 0-1 Compound of EXAMPLE A-2 Low chalking 0-1 Compound of EXAMPLE A-5 Low chalking 0-1 Compound of EXAMPLE A-6 Low chalking 0-1

[0232] 0: no cracks

[0233] 3: surface fully cracked

EXAMPLE C: THERMAL STABILITY

[0234] The thermal stability is determined by Differential Scanning Calorimetry (DSC). The measurements are carried out in a Mettler ToledoeDSC 30 machine. Approx. 10 mg of the compound of EXAMPLE A-6 is weighted into a standard DSC aluminum pan (40 microliter). The pan is sealed with an aluminium lid and punctured with a fine needle. Then, the pan is inserted in the oven and kept under nitrogen during the experiment. The thermal behaviour of the test sample is recorded in the temperature range of 30-500 C. using a heating rate of 10 C./min. The experimental data are analyzed using Mettler ToledoSTARe software (V 9.01) to determine the onset temperature of the sample decomposition. The first exothermic peak of the DSC curve is indicated in Table 2 below.

TABLE-US-00002 TABLE 2 Stabilizer DSC first exothermic peak (N.sub.2)[ C.] Compound of EXAMPLE A-6 314.2