SK145198A3 - Sterically strained phenols having higher molecular weight and method for their preparation - Google Patents

Abstract

Disclosed are sterically-protected high molecular weight phenols which are useful for thermical stabilization of various polymers of the general formula (I). Also disclosed is a method of their preparation which is characterized in reacting compounds of the general formula (III) and compounds of the general formula (IV).

Description

Higher molecular weight sterically hindered phenols and process for their preparation.

Technical field

The invention relates to the field of chemistry of higher molecular weight sterically hindered phenols which can be used for the thermal or thermo-oxidative stabilization of various polymers and processes for their preparation.

BACKGROUND OF THE INVENTION

It is well known that sterically hindered phenols are very effective stabilizers of various polymers against thermal and thermo-oxidative degradation [J. Pospisil, Antioxidants, Academia Praha, 1968]. These compounds inhibit radical processes in polymers, thereby prolonging the life of the polymers. It is also well known that low molecular weight additives are often lost from polymers due to evaporation, sublimation, and extraction of additives from polymers [J. Luston, “Developments in Polymer Stabilization- 2”, Ed. G. Scott, Applied Science Publishers, London 1980, Understand. S], [N. C. Billingham, P. D. Calvert, “Developments in Polymer Stabilization - 3., Ed. G. Scott, Applied Science Publishers, London 1980, Understand. S], [N. C. Billingham, " Oxidation Inhibition in Organic Materials ", Vol. 2, Eds. J. Pospisil, P. P. Klemchuk, CRC Press, Boca Raton, 1990, p. 249]. Due to the physical loss of additives, the life of the polymers is reduced and this is the reason for the preparation and use of higher molecular weight stabilizers or polymer-bound stabilizers [J. A. Kuczkowski, J.G. Gillick, Rubber Chem. Technol. 57, 621 (1984)], [J. Pospisil “Oxidation Inhibition in Organic Materials”, Vol. 1, Eds. J. Pospisil, P. P. Klemchuk, CRC Press, Boca Raton, 1990, p. 193];

[J. Pospisil, Adv. in Polymer Science 101 _A Springer Verlag, Berlin 1991, p. 65]. Another advantage of higher molecular weight stabilizers is that because of their much lower solubility in conventional solvents, including water, their toxicity is usually much lower than those of lower molecular weight stabilizers.

Recently, methods for the synthesis of polymeric antioxidants or antioxidants with reactive groups have been published [D. Munteanu, C. Csunderlik, I. Tincul, J. Thermal Anal. 37 _Δ 411 (1991)]; [J. Munteanu, C. Csunderlik, Polym. Degrad. Stable. 34, ₂ 295 (1991)]; [JM Herdan, M Stan, M Giurginca, Polym. Degrad. Stable. 50 _and 59 (1995)]; [MA Tlenkopatchiev, E. Miranda, R. Gabino, T. Ogawa, Polym. Bull. 35,547 (1995)].

2-Oxazolines allow a large number of reactions with different functional groups [W. Seeliger, Aufderhaar, Dieppers, Feinauer, Nehring, Thier, Hellmann,

in.

Angew. Chem., Int. Ed., 5,875 (1966)]; [J. A. Frump, Chem. Rev. 71, 483 (1971)]; [A. I. Meyers, E.D. Míhelich, Angew. Chem., Int. Ed., 15, 270 (1976)]; [M. Reuman, A.I. Meyers, Tetrahedron, 41, 837 (1985)]; [J. G. Gant, A.I. Meyers, Tetrahedron, 50,2297 (1994)]; [WITH. Kobayashi, T. Saegusa, “Ring Opening Polymerization”, Vol. 2, Eds. Ivin KJ, Saegusa T., Applied Science, London, 1984, p. 761]; [WITH. Kobayashi, Prog. Polym. Sci., 15,751 (1990)]; [K. Aoi, M. Okada, Prog. Polym. Sci., 21, 151 (1996)], which are potentially suitable for the synthesis of polymers and their modification. For example, Inata and Matsumura used various bis-2-oxazolines to increase the molecular weight of polyethylene terephthalate, which contained terminal carboxyl groups [H. Inata and S. Matsumura, J. Appl. Polym. Sci. 30,3325 (1985)]; [H. Inata and S. Matsumura, J. Appl. Polym. Sci. 32,5193 (1986)]; [H. Inata and S. Matsumura, J. Appl. Polym. Sci. 32,4581 (1986)]; [H. Inata and S. Matsumura, J. Appl. Polym. Sci. 33.

3069 (1987)]. Similar modification methods have also been presented by Loontjens et al., Sano and Böhme et al. [T. Loontjens, W. Belt, D. Stanssens, P. Weerts, Polym. Bull. 30.13 (1993)]; [Y. Sano, J. Polym. Sci., Pt. And, Polym. Chem., 27, 2749 (1989)]; [J. Bohme, D. Leistner, A. Baier, Angew. Dep. Chem., 224, 167 (1995)]; [A. Baier, F. Bohme, R. Vogel, H. Martin, D. Leistner, Angew. Dep. Chem. 228, 117 (1995)].

Baker and Saleem [Polymer, 28,2057 (1987)] used polystyrene containing 2-oxazoline groups to react with polyethylene containing carboxyl groups.

Compounds containing a sterically hindered phenol structure as well as a 2-oxazoline group have already been described by Zestermann and Hussar [US Pat. 4,205,176 (1980)]; [US Pat. 4,288,361 (1981)]. These authors prepared the compounds by reacting acids that contained a sterically hindered phenol structure with aminoalcohols in an inert solvent that allowed azeotropic removal of the water formed from the system. The aforementioned authors have declared excellent efficacy of prepared compounds in thermal stress of polyolefins, alkyd resins, waxes, mineral and vegetable oils, natural rubber, polyamides, polystyrene, ABS terpolymers and polyurethanes. However, all prepared compounds contained at least one substituent at the 4-position of the 2-oxazoline ring. This enabled them to increase the number of sterically hindered phenol groups per molecule, while increasing the molecular weight of the compounds prepared. On the other hand, substitution at the 4-position of the 2-oxazoline ring prevents further reactions associated with the opening of the 2-oxazoline ring.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide higher molecular weight sterically hindered phenols which are suitable for thermally and thermo-oxidatively stabilizing various polymeric materials and which are characterized by lower volatility from polymers.

The present invention relates to the preparation of novel higher molecular weight sterically hindered phenols, represented by formula (I)

Γ R!

H <

X-CONH-Y-ZR 2 (D wherein R ¹ and R ² are the same or different monovalent hydrocarbon groups containing 1 to 8 carbon atoms,

X is a single chemical bond, or a saturated or unsaturated hydrocarbon group containing 1 or 2 carbon atoms,

Y is a hydrocarbon group having 2 or 3 carbon atoms,

Z is -OOC-, -NH-, -S-, -O- or -NHOC-,

Q is a mono- or polyvalent radical consisting of aliphatic saturated or unsaturated, linear or branched hydrocarbon groups having 1 to 20 carbon atoms, or a mono- or polyvalent radical consisting of aliphatic saturated or unsaturated, linear or branched hydrocarbon groups having 1 to 20 carbon atoms and at least one of S, O, P or N, or a mono- or polyvalent, unsubstituted or substituted aromatic radical of 6 to 20 carbon atoms, a mono- or polyvalent, unsubstituted or substituted heteroaromatic radical of 3 to 20 atoms a mono- or polyvalent, unsubstituted or substituted aralkyl radical of 6 to 20 carbon atoms, or a biaryl compound of the general formula (Π), (II) wherein A is either a chemical bond, methylene, isopropylidene, isobutylidene, -S-, - SO-, -SO2-, -O-, -C (O) -, -OC (O) O- or -C (O) O- and n is an integer from 1 to 4.

In the compounds of formula (I), R ¹ and R ² are preferably tertiary butyl groups and X is preferably a chemical bond or a hydrocarbon chain of 2 carbon atoms.

The compounds of this invention of formula (I) are prepared according to methods well known to those skilled in the art.

According to this process, a compound of formula (ΙΠ) is reacted with a compound of formula (IV) ^R k / N πο-Ο-χ-ς> o)

R 2 ° (H 2 R-Q (IV) preferably in the melt or in a solution of one or more high boiling solvents, wherein in the compound of formula (O),

R ¹ and R ^{2 are the} same or different monovalent hydrocarbon groups containing 1 to 8 carbon atoms,

X is a single chemical bond, or a saturated or unsaturated hydrocarbon group containing 1 or 2 carbon atoms,

Y is a hydrocarbon group having 2 or 3 carbon atoms and, in the compound of formula (IV), Z is -OOC-, -NH-, -S-, -O- or -NHOC,

Q is a mono- or polyvalent radical consisting of aliphatic saturated or unsaturated, linear or branched hydrocarbon groups having 1 to 20 carbon atoms, or a mono- or polyvalent radical consisting of aliphatic saturated or unsaturated, linear or branched hydrocarbon groups having 1 to 20 carbon atoms and at least one of S, O, P or N, or a mono- or polyvalent, unsubstituted or substituted aromatic radical of 6 to 20 carbon atoms, a mono- or polyvalent, unsubstituted or substituted heteroaromatic radical of 3 to 20 carbon atoms, a mono- or polyvalent, unsubstituted or substituted aralkyl radical of 6 to 20 carbon atoms, or a biaryl compound of formula (Π), wherein A is a chemical bond, methylene, isopropylene, isobutylene, -S-, -SO-, SO ₂ -, -O-, -C (O) -, -O C (O) O-, or -C (O) A group, and n is an integer from 1 to 4.

The preparation of a compound of formula (ΙΠ) is carried out by the compound of formula (V),

wherein R ¹ and R ² are the same or different monovalent hydrocarbon groups of 1 to 8 carbon atoms,

X is a single chemical bond, or a saturated or unsaturated hydrocarbon group having 1 to 2 carbon atoms, and R ³ is a methyl or ethyl group, reacts with an excess of the amino alcohol at temperatures ranging from 100 to 200 ° C until the theoretical amount of alcohol is collected. Then, the excess amino alcohol is distilled off. The intermediate obtained is reacted with an excess of thionyl chloride under cooling with an ice bath in the presence of a solvent for 6 to 24 hours. Excess thionyl chloride and solvent are distilled off under reduced pressure and the product obtained is precipitated into water from an ethanol solution. After drying, this intermediate was treated with a solution of potassium hydroxide in methanol at reflux for 2 hours. The mixture was poured into water. The precipitated product is filtered off, washed with water and dried under reduced pressure.

The preparation of the compound of the invention according to formula (I) is carried out by a melt reaction by reacting the compound of formula (ΙΠ) and the compound of formula (IV) at a temperature above the melting point of at least one reaction component, preferably between 100 and 260 ° C, more preferably between 120 to 200 ° C, in an inert atmosphere for 1 minute to 6 hours, preferably 3 minutes to 1 hour, depending on the reaction temperature, the melting point of the reaction components and the chemical structure of the group. After cooling the reaction mixture, the resulting product is dusted and, if necessary, recrystallized from a solution of low alcohols, aliphatic or aromatic hydrocarbons.

The preparation of the compound of the invention according to formula (I) can also be carried out in solution by dissolving the compound of formula (H1) and the compound of formula (TV) in a high-boiling solvent, warming to the reaction temperature and reacting under an inert atmosphere. Preferably, high boiling solvents such as toluene, xylenes, dimethylformamide, dimethylsulfoxide, N-methylpyrrolidone, halogenated aromatic solvents, etc. are used as the solvent. The reaction in solution is carried out at a temperature between 100 and 250 ° C, preferably between 140 and 200 ° C, the reaction time being 1 to 12 hours, preferably 2 to 6 hours, depending on the reaction temperature, solvent boiling point, solvent polarity and chemical structure of the group. The reaction product is isolated after cooling to room temperature or recrystallized after concentration under reduced pressure. Low alcohols, aliphatic or aromatic hydrocarbons, etc. are used for recrystallization.

The compounds of this invention are sterically hindered higher molecular weight phenols that stabilize various polymeric materials, lubricants, oils, etc. against thermal and thermo-oxidative degradation. These compounds do not escape from the stabilized material due to the higher molecular weight.

DETAILED DESCRIPTION OF THE INVENTION

The invention is illustrated by the following examples, which are not intended to be exhaustive.

Example 1

Benzoic acid (0.0005 mol) and 1- (4-hydroxy-3,5-di-tert-butylphenyl) -2- (2-oxazolin-2-yl) ethane (0.0005 mol) were heated in an oil bath under argon atmosphere at 160 ° C for 4 hours. After cooling, the glassy solid was dissolved in ethanol (1 mL) and precipitated into water (50 mL). The precipitated product was washed with water and dried in a vacuum oven. A white solid (0.2 g) with a melting point of 125-127 ° C was obtained. The structure of the product of formula (I) was shown by 1 H NMR spectroscopy.

The compound of the invention is effective against thermo-oxidative degradation of polymers and has lower volatility from the stabilized polymer even at higher temperatures.

Example 2

The procedure of Example 1 was followed except that the solid from the synthesis was recrystallized from toluene. White crystals (0.17 g) with a melting point of 127-129 ° C were obtained.

Example 3 1- (4-Hydroxy-3,5-di-tert-butylphenyl) -2- (2-oxazolin-2-yl) ethane (0.0005 mol) and 3- (4-hydroxy-3,5-di- tert-butylphenyl) propionic acid (0.0005 mol) was heated in an oil bath under argon at 160 ° C for 2 hours. After cooling, the glassy solid was recrystallized from ethanol (2 mL). Yellowish crystals (0.29 g) with a melting point of 155-159 ° C were obtained. The structure of the product of formula (I) was shown by 1 H NMR spectroscopy.

. The compound of the invention is effective against thermo-oxidative degradation of polymers and has lower volatility from the stabilized polymer even at higher temperatures.

Example 4

Terephthalic acid (0.00025 mol) and 1- (4-hydroxy-3,5-di-tert-butylphenyl) -2- (2-oxazolin-2-yl) ethane (0.0005 mol) were heated in an oil bath under argon atmosphere at 180 ° C for 2 hours. After cooling, the product obtained was recrystallized from ethanol (5 ml). A slightly yellow powder (0.19 g) was obtained, m.p. 184-186 ° C. Further melting was found in the range 290-296 ° C.

The compound of the invention is effective against thermo-oxidative degradation of polymers and has lower volatility from the stabilized polymer even at higher temperatures.

Example 5

Stearic acid (0.0005 mol) and 1- (4-hydroxy-3,5-di-tert-butylphenyl) -2- (2-oxazolin-2-yl) ethane (0.0005 mol) were heated in an oil bath under argon atmosphere at 130 ° C for 8 hours. Upon cooling, a brownish glassy material was obtained which was dissolved in ethanol (1 mL). A pale yellow solid (0.18 g) was obtained from the opalescent brown-green solution.

The compound of the invention is effective against thermo-oxidative degradation of polymers and has lower volatility from the stabilized polymer even at higher temperatures.

Example 6

2- (4-Hydroxy-3,5-di-tert-butylphenyl) -2-oxazoline (0.0006 mol) and p-chlorothiophenol (0.0006 mol) were heated in an oil bath under an argon atmosphere at 160 ° C for 1 hour. After 5 minutes, the presence of free reactants in the system was not detected by HPLC. Upon cooling, a solid was obtained which, after crystallization from ethanol (3 mL), gave white needles (0.20 g), mp 205-206 ° C.

The compound of the invention is effective against thermo-oxidative degradation of polymers and has lower volatility from the stabilized polymer even at higher temperatures.

Example 7

2- (4-Hydroxy-3,5-di-tert-butylphenyl) -2-oxazoline (0.0006 mol) and benzoic acid (0.0006 mol) were heated in an oil bath under argon at 160 ° C for for 1 hour. The glassy reaction product was recrystallized from ethanol (1 mL). The yellowish crystals obtained had a melting point of 94-95 ° C.

The compound of the invention is effective against thermo-oxidative degradation of polymers and has lower volatility from the stabilized polymer even at higher temperatures.

Example 8

2- (4-Hydroxy-3,5-di-tert-butylphenyl) -2-oxazoline (0.0006 mol) and 4,4'-thiobis benzenethiol (0.0003 mol) were heated in an oil bath under an argon atmosphere at at 160 ° C for 1 hour. The solid obtained was dispersed in ethanol (5 ml) and filtered. The powder obtained had a melting point of 251-255 ° C.

The compound of the invention is effective against thermo-oxidative degradation of polymers and has lower volatility from the stabilized polymer even at higher temperatures.

Example 9

2- (4-Hydroxy-3,5-di-tert-butylphenyl) -2-oxazoline (0.0006 mol) and 3,3'-thiobis propionic acid (0.0003 mol) were heated in an oil bath under an argon atmosphere at 190 ° C for 1 hour. The glassy solid gave, after crystallization from ethanol (2 ml), white crystals (0.12 g), m.p. 173-175 ° C.

The compound of the invention is effective against thermo-oxidative degradation of polymers and has lower volatility from the stabilized polymer even at higher temperatures.

Example 10

2- (4-Hydroxy-3,5-di-tert-butylphenyl) -2-oxazoline (0.0006 mol) and 4-hydroxy-3,5-di-tert-butylbenzoic acid (0.0006 mol) were heated on oleic bath under argon at 190 ° C for 1 hour. The solid obtained gave, after crystallization from ethanol (2 ml), white crystals (0.25 g).

The compound of the invention is effective against thermo-oxidative degradation of polymers and has lower volatility from the stabilized polymer even at higher temperatures.

Example 11

2- (4-Hydroxy-3,5-di-tert-butylphenyl) -2-oxazoline (0.0006 mol) and sebacic acid (0.0003 mol) were heated in an oil bath under argon at 190 ° C for for 1 hour. The crystalline solid obtained after crystallization from ethanol (1 ml) gave white crystals (0.20 g), m.p. 190-191 ° C.

The compound of the invention is effective against thermo-oxidative degradation of polymers and has lower volatility from the stabilized polymer even at higher temperatures.

Example 12

2- (4-Hydroxy-3,5-di-tert-butylphenyl) -2-oxazoline (0.0006 mol) and isophthalic acid (0.0003 mol) were heated in an oil bath under argon at 190 ° C for for 1 hour. The solid obtained, after crystallization from ethanol (1 ml), gave white crystals (0.18 g), m.p. 249-251 ° C.

The compound of the invention is effective against thermo-oxidative degradation of polymers and has lower volatility from the stabilized polymer even at higher temperatures.

Example 13

2- (4-Hydroxy-3,5-di-tert-butylphenyl) -2-oxazoline (0.0006 mol) and pyridine-2,6-dicarboxylic acid (0.0003 mol) were heated in an oil bath under argon at temperature 190 ° C for 1 hour. The obtained glassy material was crystallized from ethanol (1 ml).

The compound of the invention is effective against thermo-oxidative degradation of polymers and has lower volatility from the stabilized polymer even at higher temperatures.

Example 14 1- (4-Hydroxy-3,5-di-tert-butylphenyl) -2- (2-oxazolin-2-yl) ethane (0.0005 mol) and 3- (4-hydroxy-3,5-di- tert-butylphenyl) propionic acid (0.0005 mol) was dissolved in xylene (1 mL) and bubbled with argon for 3 minutes. The reaction mixture was heated at 140 ° C for 4 hours. After cooling, the product crystals were separated, washed with xylene and dried in a vacuum oven. White crystals (0.20 g) with a melting point of 153-155 ° C were obtained.

The compound of the invention is effective against thermo-oxidative degradation of polymers and has lower volatility from the stabilized polymer even at higher temperatures.

Claims (13)

PATENT CLAIMS l. Higher molecular weight hindered phenols of general structure according to formula (I), H X-CO-NH-Y-Z-Q R 2 (D wherein R 1 and R ² are the same or different monovalent hydrocarbon groups containing 1 to 8 carbon atoms, X is a single chemical bond, or a saturated or unsaturated hydrocarbon group containing 1 or 2 carbon atoms, Y is a hydrocarbon group having 2 or 3 carbon atoms, Z is -OOC-, -NH-, -S-, -O- or -NHOC-, Q is a mono- or polyvalent radical consisting of aliphatic saturated or unsaturated, linear or branched hydrocarbon groups having 1 to 20 carbon atoms, or a mono- or polyvalent radical consisting of aliphatic saturated or unsaturated, linear or branched hydrocarbon groups having 1 to 20 carbon atoms and at least one of S, O, P or N, or a mono- or polyvalent, unsubstituted or substituted aromatic radical of 6 to 20 carbon atoms, a mono- or polyvalent, unsubstituted or substituted heteroaromatic radical of 3 to 20 carbon atoms, a mono- or polyvalent, unsubstituted or substituted aralkyl radical of 6 to 20 carbon atoms, or a biaryl compound of formula (Π), wherein A is either a chemical bond, methylene, isopropylidene, isobutylidene, -S-, -SO-, -SO2- , -ABOUT- , -C (O) -, -OC (O) O- or -C (O) O- and n is an integer from 1 to 4. The sterically hindered phenols of claim 1 wherein R ¹ and R ² are tertiary butyl groups and X is a chemical bond or a hydrocarbon group having 2 carbon atoms. A process for the preparation of higher molecular weight sterically hindered phenols according to claim 1, characterized in that the compound of formula (ΙΠ) is reacted with a compound of formula (IV), H (I) (HZ) n-Q (IV) wherein in the compound of formula (ΙΠ) are R 1 and R ² are the same or different monovalent hydrocarbon groups containing from 1 to 8 carbon atoms, X is a single chemical bond, or a saturated or unsaturated hydrocarbon group containing 1 or 2 carbon atoms, Y is a hydrocarbon group having 2 or 3 carbon atoms, and in a compound of formula (IV) Z is -OOC-, -NH-, -S-, -O- or -NHOC-, Q is a mono- or polyvalent radical consisting of aliphatic, saturated or unsaturated, linear or branched hydrocarbon groups having 1 to 20 carbon atoms, or a mono- or polyvalent radical consisting of aliphatic saturated or unsaturated, linear or branched hydrocarbon groups having 1 to 20 carbon atoms carbon and at least one of S, O, P or N, or a mono- or polyvalent, unsubstituted or substituted aromatic radical of 6 to 20 carbon atoms, a mono- or polyvalent, unsubstituted or substituted heteroaromatic radical of 3 to 20 carbon atoms , a mono- or polyvalent, unsubstituted or substituted aralkyl radical of 6 to 20 carbon atoms, or a biaryl compound of formula (Π), (II) wherein A is either a chemical bond, methylene, isopropylidene, isobutylidene, -S-, -SO- , -SO _{The 2} -, -O-, -C (O) -, -OC (O) O- or -C (O) O- group and n is an integer from 1 to 4. Process according to Claim 3, characterized in that the reaction between the compounds of formula (ΙΠ) and (IV) is carried out in the melt. The process according to claim 4, wherein the reaction is carried out at a temperature that is higher than the melting point of at least one of the reactants. Process according to Claim 5, characterized in that the reaction is carried out in a temperature range of 100 to 260 ° C, preferably between ISO and 200 ° C. Preparation process according to claim 4, characterized in that the reaction time is in the range of 1 minute to 6 hours, preferably 3 minutes to 1 hour. Process according to Claim 3, characterized in that the reaction between the compounds of formula (ΙΠ) and (IV) is carried out in solution. The process according to claim 8, wherein the reaction is carried out in an inert atmosphere at elevated temperatures. Process according to claim 1, characterized in that the reaction is carried out in a temperature range of 100 to 250 ° C, preferably between 140 to 200 ° C. Process according to Claim 8, characterized in that the reaction is carried out in a solution of one or more high-boiling solvents. Process according to Claim 1, characterized in that the reaction is carried out in a solution of aromatic and / or aprotic solvents such as toluene, xylenes, dimethylformamide, dimethylsulfoxide, N-methylpyrrolidone or halogenated aromatic solvents. Process according to Claim 8, characterized in that the reaction time is in the range of 1 to 12 hours, preferably 2 to 6 hours