DE2203407A1 - Substituted diphenylamines - Google Patents

Description

PATENT LAWYERS

TELEPHONE: COLLECTIVE NO. 225341 TELEGRAMS: ZUMPAT CHECK ACCOUNT: MUNICH 91139

BANK ACCOUNT: BANK H. HOUSES

8 MUNICH 2,

Case 3-7354 / m. 14 74

CIBA-GEIGY A.G., Basel / Switzerland

Substituted diphenylamines

The invention relates to new substituted diphenylamines which are suitable as stabilizers for organic material.

According to the present invention, novel compounds of the following general formula

provided in which R. is an alkyl radical having 1 to 4 carbon atoms, Rp is a methyl group and R _{3 is} a cycloalkyl or cycloalkenyl radical having 5 to 12 carbon atoms, which can be substituted by alkyl groups having 1 to 3 carbon atoms, or where Rp and R ₃ together with the carbon atom to which they are bonded form a saturated or unsaturated ring system with 5 to 12 carbon atoms in the ring, the ring being replaced by alkyl groups with 1 to 3 carbon atoms.

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fuel atoms or alkenyl groups with 2 to 3 carbon atoms can be substituted.

The substituent R. can be an ethyl, n-propyl, isopropyl, η-butyl, sec-butyl or tert-butyl group, but preferably a methyl group. Although R- can represent a methyl group and R ₃ a cycloalkyl group such as a cyclohexyl, cyclooctyl or cyclododecyl group, which may be substituted by alkyl groups such as methyl groups, however, R ₂ and R ₃ preferably form together with the carbon atom, to which they are bound, a saturated or unsaturated ring system with 5 to 12, preferably 6, carbon atoms in the ring. The ring system formed can be monocyclic, dicyclic or tricyclic, although this system is monocyclic for production reasons. The ring system can be substituted by alkyl groups with 1 to 3 carbon atoms, such as methyl groups, ethyl groups, n-propyl groups or isopropyl groups, or by alkenyl groups with 2 to 3 carbon atoms, such as isopropenyl groups. However, preference is given to compounds of the general formula in which R. is an alkyl group with 1 to 3 carbon atoms, R "is a methyl group and R _{3 is} an 1-methylcyclohex-1-en-4-yl group or in which Rp and R ₃ together with the Carbon atom to which they are bonded form a cyclohexyl or cyclohexenyl radical which is optionally substituted by alkyl groups having 1 to 3 carbon atoms or propenyl groups.

On bevorzugtestens the compounds of the general formula wherein R 'and R _3, together with the carbon atom to which they are attached form a cyclohexyl ring are.

Preferred compounds of the general formula therefore include the following compounds: p, p ^f -Di- (1-methylcyclohexyl) -diphenylamine, p, p'-Di (1-methyl ^ -isopropylcyclohex-1-en ^ -yldiphenylamine, p , p '-Di- (2-HiGtIIyI ^ -XSOPrOPyICyClOh ex-l-en-4-yldiphenylamine, p, p'-di- (2-methyl-3-isopropylcyclohex-l-en-3-yldiphenylamine, ρ, ρ '-Di- (l-isopropyl-4-methylcyclohexyl) -diphenyl-

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amine, ρ, ρ'-di- (l-isopropyl-S-methylcyclohexyl) -diphenylamine, ρ, ρ'-Di- [α-methyl- (1-methylcyclohex-1-en-4-yl-ethyl] -diphenylamine and ρ, ρ'-di- (1-methyl-4-isopropenylcyclohexyl) diphenylamine.

The compounds according to the invention are obtained by a process that consists in that one diphenylamine with a suitable olefin, cyclopropane or cyclobutane in the presence of a Friedel-Crafts catalyst, which is a Lewis acid or BrÖnsted acid can be alkylated.

The alkylation reaction is preferably carried out in such a way that a mixture of the diphenylamine, the olefin, and cyclopropane or cyclopropane and the catalyst to an elevated temperature, e.g. a temperature in the range from 50 to 250 C, heated, optionally in the presence of an organic solvent which is inert under the reaction conditions is, works.

Examples of suitable olefins include / \ -carene, a-pinene, ß-pinene, dipentene, dimethyl-dicyclopentadiene and 1-methylcyclohexene, which is the preferred olefin reagent. An example for a cyclopropane is / \ -Caren, while an example for a cyclobutane compound is a-pinene.

When the Friedel-Crafts catalyst is a Lewis acid, is this is preferably aluminum chloride, although zinc chloride can also be used effectively. If you have a catalyst is used which represents a Brönsted acid, this is it preferably an acid washed montmorillonite.

The present invention also relates to the use of the compounds of the general formula in small amounts as stabilizers for organic materials.

The compounds of the general formula are effective antioxidants for a wide variety of organic materials. A special cl ^ r.se of organic materials, which the oxyda-

? 0 3C :: /, / 1 20 7

tive decomposition and for which the compounds of the invention are particularly valuable antioxidants are synthetic lubricants, especially those derived from carboxylic esters and which are used at temperatures at or above about 2O4 ° C (40O ⁰ F).

Examples of such esters are lubricants based a diester of a dibasic acid and a monohydric alcohol, such as dioctyl sebacate or dinonyl adipate, or based on a triester of trimethylolpropane and a monobasic acid or a mixture of such Acids, e.g. trimethylolpropane tripelargonate, trimethylolpropane tricaprylate or mixtures thereof, or based on one Tetraester of pentaerythritol and a monobasic acid or a mixture of such acids, e.g. pentaerythritol tetracaprylate, or based on complex esters, those of monobasic acids, dibasic acids and polyhydric alcohols are derived. An example of this is a complex ester, the "of trimethylolpropane, caprylic acid and sebacic acid or" Mixtures of these acids is derived.

Other organic materials subject to oxidative decomposition for which the products of the present invention particularly valuable antioxidants include, for example, substances from the following groups:

a) Materials made from aliphatic or other hydrocarbons consist of or are based on such as gasoline, lubricating oils, lubricating greases, mineral oils or waxes;

b) natural or synthetic polymeric materials, e.g. more natural Rubber, synthetic addition polymers, such as homopolymers and copolymers of vinyl and vinylidene monomers including homopolymer seeds and copolymers of ethylene, propylene, styrene, butadiene, isoprene, acrylonitrile, vinyl chloride or vinyl acetate, synthetic polymers, obtained by condensation reactions

.den and the ether, ester (of carboxylic acids, sulfonic acids

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or carbonic acids), contain amide or urethane groups, e.g. alkyd resins and polyamide resins. In the case of these polymers the compounds of the general formula can be used during a polymer processing stage, e.g. during the Compounding rubber; <■

c) non-polymeric oxygen-containing substances, e.g. aldehydes, such as n-heptaldehyde, and unsaturated fatty acids or esters of these acids, e.g. methyl oleate or ricinoleic acid;

d) organometalloid substances such as silicone polymers, e.g. polydimethylsiloxanes, polymethylphenylsxloxanes and chlorinated ones Derivatives of these compounds, silanes, e.g. tetraalkyl or tetraarylsilanes, and organometallic substances such as organometallic polymers;

e) Vitamins, essential oils, ketones and other compounds of this type.

With regard to these other organic materials mentioned above, the compounds of the general formula are for stabilization of rubbers particularly effective. They can be used in natural or synthetic rubbers. An example for a synthetic rubber is SBR rubber (styrene butadiene rubber) Alternatively, the products can be used for it a mixture of natural and synthetic rubber, e.g. a mixture of natural rubber and Styrene-butadiene rubber to stabilize.

The compounds according to the invention of the above general formula can be used in compositions with many ingredients, i.e. compositions the at least one organic substance subject to oxidative decomposition or a mixture of one or more organic or inorganic compounds, e.g. an alcoholic or aqueous emulsion one organic material subject to oxidative decomposition.

The compounds of the general formula according to the invention are used in amounts in a range from 0.001 to 5.0% by weight,

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based on the weight of the organic material to be stabilized, used. Such compositions preferably contain the compounds of the general formula in an amount from 0.1 to 4.0% by weight based on the weight of the organic material. The amount of in any particular organic material compound of the general formula used depends not only on the type of organic material, but also on the conditions under which this material is used will, from. Thus, organic materials used at normal temperatures usually contain one lower proportion of the compounds of the above general formula than materials, such as synthetic lubricants, which are at increased Temperatures are used.

In addition to the compound of the general formula above, a synthetic lubricant may contain other additives, such as others Antioxidants, metal passivators, rust inhibitors, viscosity index improvers, Pour point depressants, dispersants or detergents and extreme pressure additives or anti-wear agents.

Suitable examples of further antioxidants include those given in the following groups a) to h):

a) alkylated and non-alkylated aromatic amines and mixtures of these compounds, for example, dioctylphenylamine, Monotert.-octylphenyl-alpha and beta naphthylamine, Dioctylphenothia- zin and phenyl-a-naphthylamine;

b) sterically hindered phenols, e.g. 2,6-di-tert-butyl-p-cresol, 4,4'-bis- (2,6-diisopropylphenol), 2,4,6-triisopropylphenol and 2,2'- Thio-bis (4-methyl-6-tert-butylphenol);

c) alkyl, aryl or alkaryl phosphites, for example triphenyl phosphite, trinonyl phosphite and diphenyl decyl phosphite;

d) esters of thiodipropionic acid, for example dilauryl thiodipropionate;

e) salts of carbamic acid and dithiophosphoric acid, e.g. Antimony diamyl dithiocarbamate and zinc diamyl dithiophosphate;

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f) Metal salts and complexes of organic chelating agents, e.g. copper-bis-ctrifluoroacetylacetonate), copper phthalocyanines and the tributyl ester of ethylenediaminetetraacetic acid (monosodium salt);

g) antioxidants which form free radicals, e.g. nitroxides, and

h) combinations of two or more antioxidants of the type mentioned above, e.g. a combination of one alkylated Amine and a hindered phenol.

Examples of suitable metal passivators include the following Substances a:

Benzotriazole, 5,5'-methylene-bis-benzotriazole, tetrahydrobenzotriazole, 2,5-dimercaptothiadiazole, salicylidene propylenediamine, Salts of salicylaminoguanidine, quinizarine, propyl gallate or Sebacic acid.

Rust inhibitors used in the lubricant compositions include those of the following groups:

a) Organic acids and their esters, metal salts and anhydrides, e.g. N-oleyl sarcosine, sorbitan monooleate, lead naphthenate and Dodecenyl succinic anhydride;

b) nitrogenous materials, e.g.

i) primary, secondary or tertiary aliphatic or cycloaliphatic Amines and amine salts of organic and inorganic acids, e.g. morpholine, stearylamine or triethanol caprylate;

ii) heterocyclic compounds such as imidazolines or oxazolines;

c) materials containing phosphorus, e.g. inorganic phosphates, Phosphonic acids or amine phosphates;

d) sulfur-containing materials, e.g. barium dinonyl naphthalene sulfonates.

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Suitable viscosity index improvers or pour point depressants are e.g. polyacrylates, polybutenes and polyvinylpyrrolidones,

Examples of dispersants or detergents include metal sulf onates, especially calcium, barium and magnesium salts, metal phenates and polybutenyl succinimides.

Extreme pressure additives or anti-wear additives, which can be used in the lubricant compositions include sulfur and / or phosphorus and / or halogen containing ones Materials such as sulfurized sperm oil, tritolyl phosphate, and chlorinated paraffins.

In addition to the uses indicated above, some of the compounds of the general formula above can also be reactive Contain ethylenic double bonds, these bonds being converted to form compounds which in turn are useful antioxidants.

The following examples are intended to explain the present invention further without, however, restricting it.

example 1

84.5 parts by weight of diphenylamine and 5 parts by weight of anhydrous aluminum chloride were continuously at 140 ° C introduced stream of dry nitrogen stirred for 15 minutes, whereupon the mixture was cooled to 11O ° C and im Run for 15 minutes with 120 parts by weight of 1-methylcyclohexene displaced. The mixture was then refluxed for 24 hours, cooled, dissolved in toluene and treated with a 10% strength Sodium hydroxide solution and then washed with water until neutral. The toluene solvent was reduced under Pressure removed, 186 parts by weight of p, p'-di- (imethylcyclohexyl) -diphenylamine in the form of a viscous green oil with the following analytical values.

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Anal yse: Ο -, - Η - ,, - Ν

do άο

Calculated: C 86.40 H 9.75 N 3.87% Found: 86.78 9.99 3.38%

The nuclear magnetic resonance spectrum (NMR spectrum) and the Infrared spectrum were consistent with that given above Structure.

Example 2

33.8 parts by weight of diphenylamine, 8 parts by weight of calcium montmorillonite (Fuller-Erde's catalyst) and 80 parts by weight of toluene were refluxed until no more water passed over in the form of an azeotrope. The toluene was then removed until the temperature of the mixture reached 135 ° C. Was then added in the course of 30 minutes, added 81.6 parts by weight / \ -carene, while keeping the temperature at 13 5 to 140 ° C. The mixture was then refluxed for an additional 5 hours. Then, the Fuller's Earth catalyst was removed by filtration and the solvent was removed under reduced pressure to give a mixture of p, p'-di- (1-methyl-4-isopropylcyclohex-1-en-4 -yD-diphenylamine and p, p ^l -di (2-methyl-4-isopropylcyclohex-l-en-4-yl) -diphenylamine in the form of a pink oil with the following analytical values.

Analysis: CopH. ^ N

Calculated: C 87.45 H 9.36 N 3.19% Found: 86.97 10.00 2.94%

The nuclear magnetic resonance spectrum and the infrared spectrum were consistent with the structure given above.

Example 3

The procedure described in Example 2 was repeated, with the difference that instead of / \ -Caren a-pinene was used, a mixture of p, p'-di- (1-methyl-4-isopropylcyclohex-1-ene -4-yl) -diphenylamine and p, p'-di- (2-methyl-3-

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isopropylcyclohex-l-en-S-yl) -diphenylamine in the form of a pink Obtained oil with the following analytical values.

Analysis: C ₃₂ H ₄₃ N

Calculated: C 87.45 H 9.36 N 3.19% '

Found: 87.59 9.95 2.86%

The NMR spectrum and the infrared spectrum were consistent with the structure given above.

Example 4

33.8 parts by weight of diphenylamine and 2 parts by weight of anhydrous aluminum chloride were added under a continuous dry ο

Brought in / nitrogen flow for 15 minutes at 140.degree

stirred, whereupon the material was ^{cooled to 110 °} C. and 81 parts by weight of carene were added in the course of 15 minutes. The mixture was then refluxed for 24 hours, cooled, dissolved in toluene and washed with 10% sodium hydroxide solution and then with water until neutral. The toluene solvent was removed under reduced pressure, 75 parts by weight of a mixture of 4,4'-di- (1-isopropyl-4-methylcyclohexyl) -diphenylamine and 4,4'-di- (1-isopropyl-3- methylcyclohexyl) diphenylamine in the form of a pink oil with the following analytical values.

Analysis: C ₃ -H ₄₇ N

Calculated: C 86.74 H 10.18 N 3.26% Found: 85.28 10.40 2.84%

The NMR spectrum and the infrared spectrum were consistent with the structure given above.

Example 5

The procedure described in Example 2 was repeated with the difference that dipentene was used instead of / \ -Carene, 89.6 parts by weight of a mixture of ρ, ρ'-di-

^ 0 J? .. ' ^; '1" ⁴ OV

[α-methyl- (l-methylcyclohex-l-en-4-yl) ethyl] diphenylamine and p, p ^l -di (l-methyl-4-isopropylcyclohexyl) diphenylamine in the form of a pink oil with the following Analysis values received.

Analysis: ^C 3p ^ 43 ^N Calculated: C 87.00 H 9.81 N 3.17% Found: 87.12 9.52 2.67%

The NMR spectrum and the infrared spectrum were consistent with the structure given above.

Example 6

The process described in Example 2 was repeated, with the difference that an equivalent amount of β-pinene was used instead of the A -carene used there

a mixture of dialkylated products was obtained.

Example 7

The procedure described in Example 2 was repeated, with the difference that 96.0 parts by weight of methylcyclopentadiene dimer were used instead of 81.6 parts by weight / \ -arena, 131.5 parts by weight of a mixture of dialkylated Products received in the form of a dark viscous oil.

Examples 8 and 9

Synthetic ester based lubricant compositions were prepared and subjected to a Pratt & Whitney Type II oxidative corrosion test subjected. The base fluid was a complex ester, that of sebacic acid, caprylic acid, and trimethylol-1,1,1-propane was derived. Each study was conducted for 48 hours at 218 ° C (425 ° F) with air was blown in at a rate of 5 liters per hour and with titanium, aluminum, silver, copper and steel samples being present was. The lubricant sample was then with 4% by weight p, p'-di-l-methylcyclohexyldipheny3amine and 0.5% by weight

2 Ü 9 3 3 ^4/1: 0 ">

Benztriazole (Example 8) or with 4% by weight of the product of Example 2 and 0.5% by weight benzotriazole (Example 9) offset.

The results obtained are given in Table I below, a comparison with an antioxidant composition which consists of 4% by weight of di-tert-octyldiphenylamine is also given and 0.5% by weight benzotriazole. The table shows the increase in acid value as mg of potassium hydroxide

2 per g and the change in weight of the samples as mg per cm

specified.

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Table I.

O CD GO

ro ο

at
game 8th Additive %
Additive % Viscosity
increase at
3 7.8 ° C (100 F) acid
worth to
took Weight
change
d.Copper sample - 9 ρ, ρ'-di-tert-octyldiphenylamine
Benzotriazole 4 %
0.5% 35.5 3.8 - 0.44 ρ, ρ'-di-l-methylcyclohexyl-
diphenylamine
Benzotriazole 4 %
0.5 % 24.8 0.63 - 0.04 Product of example 2
Benzotriazole 4%
0.5% 20.2 2.58 + 0.16

co

Example 10

20th Il 2 It 5 Il 4th It 20th ti 20th • 1 2 Il 1 Il 0.17 Il 2 Il 2 It

The following ingredients were extracted using a cooled two-roll mill [30.48 15.24 cm (12 6 inches)] during mixed for about 30 minutes.

80 parts by weight of styrene / butadiene rubber

natural rubber stearic acid zinc oxide titanium dioxide silicon dioxide Talc, polyethylene glycol (molecular weight 600), dibenzthiazyl disulfide Tetramethylthiuram disulfide Sulfur of the product of Example 5

The curing time of the formulation was determined using a suitable device (Wallace-Curometer) at 153 C, and vulcanized sheets 0.127 cm (0.050 inch) thick were pressed using a frame mold. To applying the pressure gradually to allow the air to escape, became the full pressure of 80 tons during the curing time (about 40 minutes) before releasing the pressure and removing the vulcanized sheet while it was still hot.

Samples of the vulcanized rubber products were aged for 14 days at 70 C using a container in accordance with British Standard 903, Part A 19, 19SB ₁ Method A, through which air at a rate of 9.63 l / hour ( 0.35 cubic feet / hour).

Tensile strength determinations were made on the vulcanized samples before and after aging. The crosshead speed was 50.80 cm / minute (20 inches / minute) using a load cell weighing 25 kg

2 0 9 ί'ΓΗ / 1 2 0 7

- 15 and the full scale deflection was 10 kg.

Similar studies were used for comparison purposes no antioxidant or a known antioxidant, namely di-tert-octyldiphenylamine, carried out. The received Results are summarized in Table II below.

Table II

at
game Antioxidant tensile strenght after this
aging
kg / cm2 % Changes
tion 10 none
Di-tert-octyl
diphenylamine
Product of the
Example 5 Initially
kg / cm 139
138
13 7 - 24.9
- 22.5
- 18.9 185
178
169

The superiority of the antioxidant according to the invention in comparison to a closely related common antioxidant can be clearly seen from the table above.

Examples 11-13

The following ingredients were made according to those described in Example 10 Way and mixed in the following order:

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5 8th It 80 1 Il ο, ι « ο, Part by weight

220340?

- 16 -

100 parts by weight of natural rubber 1 part by weight of stearic acid
5 parts by weight of zinc oxide

Titanium dioxide

a BaSO./CaS mixture containing 30 % CaS dibenzthiazyl disulfide tetraethylthiuram disulfide

2.5 parts by weight of sulfur

1 part by weight of the product of Examples 2, 4 or 5.

Samples of the same way as described in Example 10, vulcanized rubber products were aged for 14 days at 70 ° C in a container through which air in a quantity of 9.63 l / hour (0.35 cubic feet / hour) using British Standard Regulation 903, Part A 19, 1956, Method A used.

Before and after aging were among those described in Example 10 Conditions Tensile strength determinations made.

For comparison purposes, similar tests were carried out, with no antioxidant or the known antioxidant 2.2 ^l -methylene-bis-4-methyl-6- (l "-methylcyclohexyl) phenol being used. The results obtained are summarized in Table III below .

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- 17 Table III

at
game Antioxidant tensile strenght after this
aging
kg / cm ² % Changes
tion 11
12th
13th none
2,2'-methylene-bis-4-
methyl-6- (l "-methyl-
cyclohexyl) phenol
Product of example 2
Product of example 4
Product of example 5 Initially
kg / cm 129
165
180
179
187 - 30.7
- 9.8
- 6.3
- 6.3
- 9.7 186
183
192
191
207

Again, the excellent antioxidant activity is that of the present invention Products clearly visible.

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Claims (1)

Claims where R. is an alkyl radical with 1 to 4 carbon atoms, Rp is a methyl group and R- is a cycloalkyl or cycloalkenyl radical with 5 to 12 carbon atoms optionally substituted by alkyl groups with 1 to 3 carbon atoms or where R ₂ and R ₃ together with the Carbon atom to which they are bonded form a saturated or unsaturated ring system with 5 to 12 carbon atoms in the ring which is optionally substituted by alkyl groups with 1 to 3 carbon atoms or by alkenyl groups with 2 to 3 carbon atoms. 2.) Compounds according to claim 1, characterized in that R ^ is a methyl group and R- and R ₃ together with the carbon atom to which they are bonded, an optionally by alkyl groups with 1 to 3 carbon atoms or by alkenyl groups with 2 to 3 carbon atoms substituted saturated or unsaturated ring system with 3 to 12 carbon atoms in the ring. 3.) Compounds according to claim 1, characterized in that the ring system is a cyclohexyl ring. 3.) Compounds according to claim 1, characterized in that R ₁ is an alkyl group having 1 to 3 carbon atoms, R is a methyl group and R _{3 is} a l-Methyl-cyclohex-l-en-4-yl radical, or R ^ and R ₃ together with the carbon atom to which they are attached, an optionally substituted by alkyl 20983A / 1207 groups with 1 to 3 carbon atoms or through the propenyl group substituted cyclohexyl or cyclohexenyl radical. 5.) Use of the compounds according to claim 1 for stabilization of organic material. 6.) Use according to claim 5, characterized in that the organic material is a synthetic lubricant. 7.) Use according to claim 6, characterized in that the synthetic lubricant derived from carboxylic acid esters is. 8.) Use of the compounds according to claim 1 for stabilization of rubber. 209834/1207