JPH02194094A - Nitrogeneous additive having antioxidant action and lubricating composition containing said additive - Google Patents

Abstract

PURPOSE: To obtain an antioxidant additive useful for a lubricant compsn. by incorporating a specific compd. as the active component into the same.

CONSTITUTION: This additive contains a compd. represented by formula I [wherein Ar and Ar' are each arom. provided that Ar' may be substd. by H and that Ar and Ar' may combine with each other through N to form an arom. heterocycle; R and R' are each a 2-18C linear or branched alkylene group optionally substd. by a halogen, OH, or NH₂; X is O, S, or NH; a is 0-5; Y is a group represented by one of formulas II to V; R₁ and R₂ are each H, a 1-12C alkyl, an alkenyl, a cycloalkyl, or an aryl; Ar is an aryl group having at least one phenol group; and R₃ is H or an (un)satd. linear or branched alkyl group] as the active component. A natural or synthetic lubricant is compounded with 0.01-10 wt.% above-mentioned additive and if necessary an antiseptic, a detergent, an antiabrasion agent, a dispersant, an antifoaming agent, etc., to give a lubricant compsn.

COPYRIGHT: (C)1990,JPO

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to novel antioxidant additives and lubricating compositions containing said additives.

It is known that lubricating oils and in particular crank base oils for internal combustion engines contain various additives that are used to improve their properties. Some of these additives are used to protect oils from oxidation caused by high temperatures or by certain metal ions dispersed in the oil.

This lubricant degradation is associated with thermal and oxidative degradation of the oil and additives. The decomposition results in the formation and deposition of carbonaceous material on the piston wall. When these deposits become very large,
This creates rubber, which causes the piston to become stuck and increases wear on the moving metal parts. Therefore, it is important to limit lubricant degradation as much as possible by using economically reasonable concentrations of effective antioxidant additives.

The protection of lubricants by the use of various organic additives has been widely described. Depending on their mode of action, there is a general distinction between these compounds, on the one hand, as free group inhibitors (hindered phenols, aromatic amines, phenothiazines, etc.) and on the other as hydroperoxides or peroxides (
metal dithiocarbamates or dithiophosphates, phosphites, and dithioethers).

Metal deactivators are also known that prevent metal ions present in the oil or on the surface from causing autoxidation of the lubricant.

Among these compounds, aromatic amines, more particularly phenothiazine derivatives, are effective as they act by a number of mechanisms: hydroperoxide decomposition, electron transfer agents, metal chelates and oxygen acceptors.

Thus, US Pat. No. 2,781,318 describes alkylphenothiazine synthetic lubricants in which the alkyl group is carried by the aromatic carbon of the phenothiazine.

U.S. Patent No. 3,536,706 discloses that the aromatic nucleus has 4 carbon atoms.
The use of phenothiazines substituted by tertiary alkyl groups having from 1 to 12 or by aryl groups is described.

U.S. Pat. No. 3,803,140 describes N-alkyl- or N-
The use of tert-alkyl derivatives of alkenylphenothiazines has been suggested. In particular, tert-alkyl derivatives of phenothiazines which are not substituted on nitrogen are preferred.

US Pat. No. 3,344,068 describes the use of antioxidants derived from aromatic amines in ester-based synthetic lubricants. These additives may be N-alkylphenothiazines substituted with at least one alkyl group on the aromatic nucleus.

US Pat. No. 3,376,224 claims antioxidants derived from phenothiazines which are substituted on the nitrogen atom by an alkoxymethyl group.

International Application No. 88/02.007 describes the preparation and use of N-alkylthioalkylphenothiazines obtained with phenothiazines and alkylthioalkanols. The presence of sulfur atoms enhances the antioxidant power of phenothiazines thus substituted.

The inventors have found that the properties of antioxidant additives containing aromatic nitrogen can be improved by the presence of aminoalkyl chains.

The solubility of these additives in lubricants of synthetic or mineral origin is considerably improved.

The presence of the amine functionality introduces other functional groups into the molecule, enhancing the antioxidant power of the antioxidant or imparting other useful properties to the antioxidant.

The aromatic nitrogen-containing antioxidant additive of the present invention has the general formula (I) 2Ar-N-(R-X)a-R'-Y
(I) Ar'(H) [In the formula, Ar and Ar' represent the same or different aromatic groups, Ar' may be substituted with a hydrogen atom, etc., and Ar and Ar' are may be combined to form an aromatic heterocycle, R and R' are the same or different and optionally substituted with halogen or -OH or -NH, cz C1m
, preferably C, -C, and preferably C5, represents a linear or branched alkylene group, X represents oxygen or sulfur atom or -NH- group, and a represents O to 5. , preferably an integer from 0 to 2, and Y is -NRIR2(I[) (wherein R1 and R7 are the same or different and represent a hydrogen atom or a CICl alkyl, alkenyl, cycloalkyl or arylalkyl group. ), -N=CH-Ar r (DI) (wherein Art represents an aryl group containing at least one phenol group), -NRr -Go-Ar r (IV)
(In the formula, R8 and Ar are as described above.) and represents a sum or unsaturated linear or branched alkyl group.

) represents a group selected from the group consisting of ].

The aromatic nitrogen may be an amine group bonded to l or two aromatic groups A' and Ar'. Ar may be, for example, a phenyl, naphthyl, anilinophenyl or phenothiazinyl group (where Ar' is substituted by a hydrogen atom). A.
r and Ar' may be the same or a phenyl group.

Aromatic nitrogen may also form part of a heterocycle.

In this case, Ar and Ar' are bonded via the nitrogen atom to form an aromatic heterocyclic structure such as a phenothiazine, imidazole, benzimidazole, triazole or benzotriazole.

Phenothiazine derivatives are preferably used.

Ar and Ar' are alkyl or aryl, preferably C
It may be substituted with a l-CI2 group, a hydroxyl group, an alkoxy group, an alkylthio group, or a halogen.

R1 and R1 preferably represent a hydrogen atom or a C, -C, alkyl group.

According to another feature of the invention, R1 is a hydrogen atom, R
3 represents an arylalkyl group having the general formula: -C11=Ar+ (wherein, Art is as defined above).

The introduction of the phenolic group Ar enhances the antioxidant power of the antioxidant additive.

Ar groups containing at least one phenolic OH are, for example, phenol, p-terL-butylphenol, 2.6-Lert-butyl,
2.4-di-tert-amylphenol, dodecylphenol, sulfurized dodecylphenol, catechol, β-
Derived from naphthol or resorcinol.

R1 advantageously represents a C2-C, olefin oligomer, the molecular weight of which is from 500 to 3,000, preferably from 800 to 1,500.

These additives can be manufactured by any known method.

For example, Y=NR,R, can be obtained by alkylating a compound having aromatic nitrogen. Compounds with aromatic nitrogen are either aromatic amines such as aniline, naphthylamine, diphenylamine, 3-aminophenothiazine or aminodiphenylamine or nitrogen-containing heterocycles such as phenothiazine, imidazole, benzimidazole, triazole or benzotriazole. It is. The use of other heterocyclic compounds is intended with the proviso that the heterocycle contains a nitrogen atom that can be alkylated.

Acrylamide, chloroacetamide, iodoacetamide, acrylonitrile and 3-chloropropionitrile are good alkylation reactants. The alkylation reaction is followed by hydrogenation of the nitrile or amide group.

For example, phenothiazines are described by N. L. Smith
) [Journal of Organic Chemistry (J, Org, Chem,) No. 1]
5, p. 1129, 1950], Triton
Condensation with acrylonitrile under cyanoethylation conditions using a greater than stoichiometric amount of acrylonitrile in the presence of an alkaline catalyst such as Lon) B. The intermediate is then reduced to N-aminopropylphenothiazine by catalytic hydrogenation under hydrogen and ammonia pressure in an autoclave.

Another method is to react an epoxide such as ethylene oxide or propylene oxide with aromatic nitrogen and then treat it with ammonia or the general formula: R,NHR2, where R+ and R2 are as above. It consists of carrying out amithrisis of an alcohol intermediate.

Naturally, compounds with a greater than 1 can be obtained by successive reactions with many molecules of epoxides or mixtures of epoxides.

If R2 is an arylalkyl group having at least one phenolic OH, the Mannich reaction is advantageously used for its synthesis.

The Mannich base has the general formula (I) (wherein Y is -NR,R
.

and at least one of R1 or R1 is a hydrogen atom. ) can be obtained by reacting a phenol having at least one active hydrogen in its molecule with an aldehyde.

Linear or cyclic alkyl aldehydes or else aromatic aldehydes are used, but preferably formaldehyde or derivatives such as paraformaldehyde, acetaldehyde or propionaldehyde are used.

In phenol, generally phenol itself, p-tert
-Butylphenol, 2.6-Lert-butylphenol, 2,4-di-tert-amylphenol, jerL-butyl-p-cresol, dodecylphenol, dodecylphenol sulfide, catechol, β-su7
selected from toll or resorcinol.

Mannich base is generally 0.8 to 1 mole of phenol.
1.5 to 1.5 mol, preferably 1.2 mol of the aldehyde and 8 to 2.5 mol, preferably 1 mol of the general formula (I
) can be obtained by adding a compound represented by

The reaction is carried out under an inert gas atmosphere such as nitrogen at 60 to 13
This is carried out with stirring at a temperature of 0°C, preferably about 100°C, for 2 to 10 hours.

The operation is generally carried out in the presence of a polar solvent such as isopropanol or an aromatic solvent such as toluene or xylene.

After the reaction, the solvent is removed to recover the Mannich base which can be used directly in the lubricating compositions of the present invention.

Compounds with oxaldine (oxald 1ne) functional group or Schiff base (Y is -N=CH-Ar l)
has the general formula: Ar.

It is obtained by reacting an aldehyde represented by -CHO with a compound represented by general formula (I) (wherein Y is represented by NR, R, and R8 and R2 are hydrogen atoms).

The compound Ar, -CHO is salicylaldehyde, Ler
t-Butylsalicylaldehyde, 3,5-di-tert
-butyl-4-hydroxybenzaldehyde or 3,5
-di-tert-butyl-4-hydroxy-3-phenylpropionaldehyde is preferred.

Compounds with amide functional group (Y is -NR, -GO-A
r, ) represents an acid represented by the general formula: Ar, -CO, H, represented by the general formula (I) (wherein, Y is represented by NRIRz, R3
and at least one of R1 is a hydrogen atom. ) can be obtained by reacting with a compound represented by

The compound Art-Go2H is salicylic acid, tert-butylsalicylic acid or 3,5-di-tart-butyl-4
-Hydroxy-3-phenylpropionic acid is preferred.

Formation of the Schiff base or amide generally occurs by heating the reactants under the same operating conditions as to obtain the Mannich base.

It is obtained by reacting a compound having an imide functional group (Y is represented by NRIRz, and Ro and R2 are hydrogen).

The introduction of imide functionality into the molecule imparts dispersion properties to the additives of the invention.

The succinic anhydride used is generally substituted with alkyl groups, preferably oligomers.

Oligomers are produced by oligomerization of C, -C, olefins. The oligomer has a molecular weight of 500-3000, preferably 800-1500. The oligomer contains residual unsaturation and reacts with maleic anhydride to form substituted succinic anhydride.

The operation is generally carried out using 0.5 to 1.5 mol, preferably 1 mol, of the compound of general formula (I) per mol of anhydride, and a solvent such as toluene or xylene which can remove water formed during the reaction by co-distillation. This is carried out by condensation within.

This reaction results in the formation of amide and imide functional groups.

After the reaction, the additives used in the lubricating compositions of the present invention can be recovered by removing the solvent.

The additive is mixed into natural or synthetic lubricating oils or mixtures thereof.

Examples include mineral oils and hydrorefined oils of normal or refined, paraffinic, naphthalic composition. polybutenes, alkylbenzenes such as zincylbenzene and tetradecylbenzene, polypropylene glycol ethers or esters, polycarboxylic acid esters such as methyl adipate and pentaerythritol heptanoate,
Also suitable are synthetic oils such as silicone oils such as polysiloxanes, full or partial esters of phosphoric acids, especially trinyresyl phosphates and alkyl phosphoric acids.

The concentration of the additive of the present invention in the lubricating composition used in the application is generally 0. The amount is about 01 to 10% by weight, preferably 0.1 to 2.5% by weight.

The antioxidant compounds of the present invention may be combined with other conventional additives or lubricants, such as corrosion inhibitors, detergents and anti-wear, dispersing and anti-foam additives.

The lubricating composition containing the antioxidant of the present invention can be used particularly as a crank base oil for internal combustion engines.
al) Used as casing oil and gear oil to facilitate metal machining.

The following examples are illustrative of the invention and are not intended to be limiting.

Example I (Preparation of N-aminopropylphenothiazine) 2.5 mL of a methanol solution containing 40% benzyltrimethylammonium hydroxide was added to 10 mL of phenothiazine.
09 (0.5 mol) and acrylonitrile 530 g (1
0 mol) was added dropwise to the reactor containing 0 mol) and the temperature was cooled to below 10°C. The whole was heated to 80° C. for 1 hour and 30 minutes. Thereafter, excess acrylonitrile was removed by vacuum distillation. The solid was isolated and recrystallized twice from acetone. 1O-7 enothiazinylpropionitrile 6
Obtained in 6% yield (83.99, melting point: 156-157°C).

50.6 g of this nitrile was placed in a Soxhlet extractor and extracted continuously with 1000100 O of ethyl ether containing 169 lithium aluminum hydride. After 72 hours of reaction, the ether solution was diluted with 16 blades of water for 55 hours.
．． 12ml of 25% sodium hydroxide! and treated twice with 50 mff1 of water. Insoluble salts were filtered and dried, and ether was removed by distillation to obtain N-aminopropylphenothiazine (yield near 0%).

Example II (Mannich base with 2,6-tart-butylphenol) N-aminopropylphenothiazine 2.569 (0,0
1 mol), 2.6-di-t,arL-butylphenol 1, 96 g (0.01 mol) and ethanol 1
00ml was introduced into a 250+IIQ capacity reactor without stirring. Stirring was continued for 10 minutes at ambient temperature, then 0.33y (0.011 mol) of paraformaldehyde was added. The mixture was refluxed for 24 hours and then left at ambient temperature for a further 96 hours. The solid was separated by filtration, washed with ethanol and dried in an oven at 100 °C (
m: 2-31 g, yield: 51%).

Example m (Mannich base using sulfurized dodecylphenol) a) Introducing 141.59 g of sulfur chloride into a reactor containing 550 g of dodecylphenol over a period of about 1 hour while maintaining the temperature at 20-30° C. under a nitrogen atmosphere. did. After the addition is complete,
The mixture was heated at 150°C for 1 hour, 180°C for 1 hour, and 200°C for 1 hour while maintaining a nitrogen flow to remove hydrogen chloride. It was then cooled with a stirrer while maintaining a slow flow of nitrogen (the product obtained had a sulfur content of 1000%) b) 2.56 g (0.01 mol) of N-aminopropylphenothiazine , 2.93 g of sulfurized dodecylphenol (obtained in II [a)]
(0,005 mol) and 200 m (1) of ethanol were introduced into a 250 mjl reactor with stirring.

Stirring was continued for 5 minutes at ambient temperature, then 0.33 g of paraformaldehyde was added and the mixture was refluxed for 8 hours.

Remove the produced water using a solvent when it is produced t;0
The mixture was then cooled. After 2 days at ambient temperature, the resulting precipitate was filtered off and then dissolved in dichloromethane. After filtration and removal of solvent, 1.3 g of chestnut brown powder was recovered.

The infrared absorption spectrum demonstrated the presence of two absorption bands for nitrogen at 3300 cm-', which are characteristic of the desired product.

Example 1 16.79 (0.1 mol) of 7-thylamine was heated with 4.09 g of sodium amide over 200 g of toluene under stirring and reflux. After 1 hour, 12.1 g of 3-dimethyl-amino-1-chloropropane was added dropwise and heating under reflux was continued for a further 4 hours. After cooling, wash the mixture with water,
The toluene solution was dried over WliLra magnesium. After evaporation of the solvent, a yellow oil was recovered consisting mainly of (N,N-dimethyl-3-aminopropyl)naphthylamine.

Example V 20 g (0.1 mol) of phenothiazine and 4.1 g of sodium amide were heated in 200 mff of toluene under stirring and reflux. After 1 hour, this pre-chilled solution was diluted with 1.
Poured into 250 mff of 2-di(2-chloroethoxy)ethane. The mixture was heated under reflux for 4 hours. Toluene and excess 1,2-di(2-chloroethoxy)ethane were removed by evaporation.

The residue was taken together with 200 mM of a 30% aqueous ammonia solution and methanol 100+*Q, and the whole was heated at 60°C for 72 hours.
I left it for a while. The alcohol was removed and the product was extracted twice with toluene 150+β. The organic phase was washed twice with 50 mn of water and dried over magnesium sulphide. After evaporation of the solvent, a product consisting mainly of 2-(2-aminoethoxy)(2-phenothiazinyl-ethoxy)ethane was recovered.

Example 2 The oxidative stability of lubricating compositions containing the additives of the present invention was evaluated in this example. The test is carried out using a cylinder pressurized with oxygen at 160° C. in the presence of metal catalyst, combustion catalyst and water, partially mimicking the conditions the oil is exposed to in a gasoline engine.

The metal catalyst is a mixture of soluble lead, copper, iron, manganese, and tin naphthinate.

The oxidative stability of lubricants is evaluated by measuring the induction time, ie the time interval between the start of the test and the sudden drop in pressure in the cylinder.

The longer the induction time, the more effective the antioxidant additive that is part of the lubricating composition.

Table 1 Control lubricant A A+0.3% of additive obtained in Example I Additive 0.5% obtained in Example A Additive 0.5% obtained in A10 Example ■ Additive 1% obtained in A10 Example ■ Additive 1% obtained in Human Example ■ Additive 0.5% obtained in A10 Example ■ Additive 0.5% obtained from Hachijinshi Example V patent application agent

Claims (1)

[Claims] 1. In a lubricating oil additive containing aromatic nitrogen and having an antioxidant effect, the additive has the general formula (I): ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) [Formula wherein Ar and Ar' represent the same or different aromatic groups, Ar' may be substituted with a hydrogen atom, and Ar and Ar' are bonded via nitrogen to form an aromatic heterocycle; R and R' are the same or different and optionally substituted with halogen or -OH or -NH_2 groups, C_2-C_
1_2 represents a linear or branched alkylene group, X represents an oxygen or sulfur atom or -NH- group, and a is 0 to 5
is an integer of -NR_1R_2(II), where R_1 and R_2
are the same or different, hydrogen atoms or C_1-C_1_2
Represents an alkyl, alkenyl, cycloalkyl or arylalkyl group. ), -N=CH-Ar_1(III) (wherein Ar_1 represents an aryl group having at least one phenol group), -NR_1-CO-Ar_1(IV) (wherein R_1
and Ar_1 are as described above. ) and ▲Mathematical formulas, chemical formulas, tables, etc.▼(V) (In the formula, R_
3 represents a hydrogen atom or a saturated or unsaturated linear or branched alkyl group. ) represents a group selected from the group consisting of ] A lubricating oil additive characterized by the following. 2. Lubricating oil additive according to claim 1, characterized in that 2, R and R' represent the same or different C_2-C_6, preferably C_3, linear or branched alkylene groups. 3. The lubricating oil additive according to claim 1 or 2, wherein a is an integer from 0 to 2. 4. The lubricating oil additive according to claim 1, wherein R_1 and R_2 are the same or different and represent a hydrogen atom or a C_1-C_4 alkyl group. 5, R_1 represents a hydrogen atom, R_2 has the general formula: -C
Claim 1 characterized in that it is an arylalkyl group represented by H_2-Ar_1 (wherein Ar_1 is an aryl group having at least one phenol group).
Lubricating oil additives as described in. 6. Aryl group Ar_1 is phenol, p-tert
-butylphenol, 2,4-di-tert-butylphenol, 2,4-di-tert-amylphenol,
Lubricating oil additive according to claim 5, characterized in that it is derived from di-tert-butyl-p-cresol, dodecylphenol, sulfurized dodecylphenol, catechol, β-naphthol or resorcinol. 7. The lubricating oil additive according to claim 1, characterized in that R_3 is an oligomer of C_2-C_5 olefins having a molecular weight of 500 to 3000, preferably 800 to 1500. 8. The lubricating oil according to any one of claims 1 to 7, wherein Ar represents a phenyl, naphthyl, anilinophenyl or phenothiazinyl group, and Ar' is substituted with a hydrogen atom. Additive. 9. The lubricating oil additive according to any one of claims 1 to 7, characterized in that Ar and Ar' are the same and represent a phenyl group. 10. Any one of claims 1 to 7, characterized in that Ar and Ar' are bonded via nitrogen to form an aromatic heterocyclic structure such as phenothiazine, imidazole, benzimidazole, triazole or benzotriazole. The lubricating oil additive according to claim 1. 11. The lubricating oil additive according to claim 10, wherein the aromatic heterocyclic structure is a phenothiazine. 12. Natural or synthetic lubricating oil and 0.01 to 10% by weight
A lubricating composition characterized in that it contains a lubricating oil additive according to any one of claims 1 to 10, preferably from 0.1 to 2.5% by weight. 13. Lubricating composition according to claim 12, characterized in that it contains other additives conventional for lubricants, such as corrosion inhibitors, detergents' and anti-wear agents, dispersants and antifoam agents. thing.