COMPOUND, RUBBER MIXTURE CONTAINING THE COMPOUND, VEHICLE TIRE WHICH HAS AT LEAST ONE COMPONENT COMPRISING THE RUBBER MIXTURE, METHOD FOR PRODUCING THE COMPOUND, AND USE OF THE COMPOUND AS AN AGING PROTECTION AGENT AND/OR ANTIOXIDANT AGENT AND/OR ANTIOZONANT AND/OR DYE

Abstract

The invention relates to a compound, to a rubber mixture containing the compound, to a vehicle tire comprising the rubber mixture in at least one component, to a process for producing the compound and to the use of the compound as an aging stabilizer and/or antioxidant and/or dye.

The compound according to the invention has the formula I).

##STR00001##

Claims

1-12. (canceled)

13. A rubber mixture comprising a compound of formula I): ##STR00017##

14. The rubber mixture of claim 13, the mixture contains at least one diene rubber.

15. The rubber mixture of 3, wherein it contains at least one diene rubber selected from the group consisting of natural polyisoprene (NR), synthetic polyisoprene (IR), butadiene rubber (BR), solution-polymerized styrene-butadiene rubber (SSBR), emulsion-polymerized styrene-butadiene rubber (ESBR), butyl rubber (IIR), and halobutyl rubber.

16. The rubber mixture of claim 14, wherein the mixture is incorporated into a vehicle tire.

17. The rubber mixture of claim 16, the mixture is comprised in at least one external component of the tire, wherein the external component is a tread, a sidewall and/or a flange profile.

18. A method for producing a compound comprising: a) providing the substance of formula A) ##STR00018## b) providing methyl isobutyl ketone (MIBK) and hydrogen or methyl isobutyl ketone (MIBK) and formic acid; c) reacting the substance according to step a) with the substances according to step b) to afford the substance of formula C) ##STR00019## d) providing a Lewis acid, such as in particular boron tribromide (BBr.sub.3), aluminum trichloride (AlCl.sub.3), aluminum tribromide (AlBr.sub.3), boron trifluoride diethyl etherate (BF.sub.3*OEt.sub.2) or tin tetrachloride (SnCl.sub.4), or a Brønsted acid, such as in particular hydrogen iodide (HI) or hydrogen bromide (HBr); e) reacting the substance of formula C) with the substance from step d) to afford the substance of formula I) ##STR00020##

19. A method for producing a compound comprising: a1) providing the substance of formula A) ##STR00021## b1) providing a Lewis acid, such as in particular boron tribromide (BBr.sub.3), aluminum trichloride (AlCl.sub.3), aluminum tribromide (AlBr.sub.3), boron trifluoride diethyl etherate (BF.sub.3*OEt.sub.2) or tin tetrachloride (SnCl.sub.4), or a Brønsted acid, such as in particular hydrogen iodide (HI) or hydrogen bromide (HBr); c1) reacting the substance according to step al) with the substance from step b1) to afford the substance of formula C1) ##STR00022## d1) providing methyl isobutyl ketone (MIBK) and hydrogen; e1) reacting the substance of formula C1) with methyl isobutyl ketone (MIBK) from step d1) to afford the substance of formula I) ##STR00023##

20. The rubber mixture of claim 13, the rubber mixture is used as an aging stabilizer and/or antiozonant in particular in vehicle tires and/or technical rubber articles, such as in particular an air spring, bellows, conveyor belt, belt, drive belt, hose, rubber band, profile, a seal, a membrane, tactile sensors for medical applications or robotics applications, or a shoe sole or parts thereof and/or oils and/or lubricants.

21. The rubber mixture of claim 13, the rubber mixture is used a rubber article, in particular an air spring, a bellows, conveyor belt, belt, drive belt, hose, rubber band, profile, a seal, a membrane, tactile sensors for medical applications or robotics applications, or a shoe sole or parts thereof.

22. The rubber mixture of claim 13, the rubber mixture is used in oils and lubricants, such as in particular fuels or fluids for engines.

23. The rubber mixture of claim 13, the rubber mixture is incorporated as a dye in fibers and/or polymers and/or paper and/or in paints and coatings.

Description

[0150] The invention shall be more particularly elucidated below with reference to working examples.

[0151] The component of formula I) was produced as follows:

X1): Synthesis of N-(1,3-dimethylbutyl)-N′-p-methoxyphenyl-p-phenylenediamine (compound of formula C)) according to step c)

[0152] ##STR00012##

[0153] 5.00 g (23.3 mmol, 1 eq.) of 4-(4-methoxyphenylamino)aniline, 2.00 g of Pd/C (palladium on carbon C) (5%) (0.2 g on 4.67 mmol of substrate) and 50.0 mL of methyl isobutyl ketone (MIBK) were weighed into a stainless steel autoclave fitted with a Teflon inliner. The autoclave was then pressurized to 20 bar with hydrogen (H.sub.2) and stirred at 60° C. for 10 hours. After termination of the reaction, the excess hydrogen was blown off and the suspension filtered through diatomaceous earth (Celite®) and washed with ethanol. The filtrate was concentrated to dryness and dried under vacuum. The residue was purified over silica gel (cyclohexane/acetic ester 100:0.fwdarw.80:20). Orange oil; yield 5.6 g (80% of theory).

[0154] .sup.1H-NMR (500 MHz, DMSO-d6) δ=8.09 (s, 1H), 6.94 (td, J=7.6, 1.5 Hz, 1 H), 6.88 (dd, J=7.6, 1.4 Hz, 1 H), 6.69-6.63 (m, 2H), 6.51 (d, J=8.4 Hz, 1 H), 6.27 (dd, J=8.5, 2.5 Hz, 1H), 6.21 (d, J=2.5 Hz, 1H), 4.82 (d, J=8.9 Hz, 1H), 3.30 (dt, J=8.6, 6.5 Hz, 1H), 1.70 (dp, J=13.5, 6.7 Hz, 1H), 1.38 (dt, J=13.9, 7.1 Hz, 1H), 1.16 (dt, J=13.5, 6.8 Hz, 1H), 1.02 (d, J=6.1 Hz, 3H), 0.87 (dd, J=19.4, 6.6 Hz, 6H).

[0155] .sup.13C-NMR (126 MHz, DMSO-d6) δ=151.8, 143.0, 140.0, 133.0, 120.7, 116.0, 114.5, 113.6, 55.2, 46.1, 45.9, 26.3, 24.5, 22.8, 22.6, 20.87 (46.1 and 45.9 is splitting due to enantiomers).

[0156] ESI-MS (electrospray ionization mass spectrometry) [M+H].sup.+=299.

Synthesis of N-(1,3-dimethylbutyl)-N′-p-hydroxyphenyl-p-phenylenediamine (inventive compound of formula I)) according to step e)

[0157] ##STR00013##

[0158] Under argon, 5.70 g (19.1 mmol, 1 eq.) of N-(1,3-dimethylbutyl)-N′-p -methoxyphenyl-p-phenylenediamine were dissolved in 20.0 mL of dry dichloromethane (DCM) and cooled to 0° C. 5.52 mL (57.3 mmol, 5 eq.) of boron tribromide were dissolved in 15 mL of dry DCM and carefully added dropwise. The mixture was stirred overnight and the reaction was terminated under protective gas and with ice cooling by addition of saturated NaHCO.sub.3 solution. 50 mL of a 3:1 mixture of acetic acid/isopropanol were additionally added. The organic phase was washed with saturated NaHCO.sub.3 solution and saturated NaCl solution and dried over MgSO.sub.4. Once filtration was complete, the solvent was concentrated to dryness and dried under vacuum. Pale-violet to blue solid; yield 4.8 g (88% of theory).

[0159] .sup.1H-NMR (500 MHz, DMSO-d6) δ=8.63 (s, 1H), 6.95 (s, 1H), 6.76 (d, J=8.7 Hz, 2H), 6.71 (d, J=8.8 Hz, 2H), 6.59 (d, J=8.7 Hz, 2H), 6.51-6.44 (m, 2H), 4.71 (d, J=8.2 Hz, 1 H), 3.40-3.31 (d, J=6.9 Hz, 1H), 1.73 (dp, J=13.4, 6.7 Hz, 1 H), 1.49-1.37 (m, 1H), 1.23-1.15 (m, 1H), 1.05 (d, J=6.1 Hz, 3H), 0.91 (d, J=6.6 Hz, 3H), 0.87 (d, J=6.6 Hz, 3H).

[0160] .sup.13C-NMR (126 MHz, DMSO-d6) δ=149.8, 142.5, 138.1, 133.9, 119.9, 117.0, 115.6, 113.3, 46.1, 45.9, 26.3, 24.5, 22.8, 22.6, 20.8 (46.1 and 45.9 is splitting due to isomers).

[0161] ESI-MS [M+H].sup.+=285.

[0162] In an alternative variant of the reaction according to step c), the intermediate compound of formula C) was produced as follows:

X2): Synthesis of N-(1,3-dimethylbutyl)-N′-p-methoxyphenyl-p-phenylenediamine

[0163] ##STR00014##

[0164] Under protective gas, 0.40 g of palladium on carbon (5%) was suspended in 20 mL of dry ethanol and 1.00 g (4.67 mmol, 1 eq.) of 4-(4-methoxyphenylamino)aniline, 0.88 mL (23.3 mmol, 5 eq.) of formic acid (23.3 mmol, 5 eq.) and 1.17 mL (9.33 mmol, 2 eq.) of methyl isobutyl ketone were added successively. The mixture was heated for 4 hours under reflux, the solids were filtered off and the solvent was removed under vacuum. The residue was purified over silica gel (cyclohexane/acetic ester 100:0.fwdarw.80:20). Orange oil; yield 1.0 g (73% of theory).

[0165] The spectra are identical to the first performance (X1).

[0166] The performance of process step c) according to X1) is preferred due to the better reproducibility and fewer generated byproducts compared to that according to X2) (formate as byproduct from the reaction of amine and formic acid).

[0167] The inventive compound was also produced by an alternative synthesis route as follows:

Synthesis of N-p-hydroxyphenyl-p-phenylenediamine (compound of formula C1) according to step c1)

[0168] ##STR00015##

[0169] Under protective gas, 20 mL of degassed acetic acid and 10 mL of hydrobromic acid were initially charged and 1 g (4.67 mmol, 1 eq.) of 4-(4-methoxyphenylamino)aniline was dissolved therein and stirred at 120° C. for 24 hours. Once the solution had been brought to RT, it was neutralized with saturated NaHCO.sub.3 solution and extracted with a 3:1 acetic ester/isopropanol mixture. The solvent was removed and the residue purified over silica gel (cyclohexane/acetic ester 1:1). Brown solid; yield 0.7 g (75% of theory).

[0170] .sup.1H-NMR (500 MHz, DMSO-d6) δ=8.64 (s, 1H), 6.94 (s, 1H), 6.73-6.68 (m, 4H), 6.59 (d, J=8.8 Hz, 2H), 6.48 (d, J=8.6 Hz, 2H), 4.56 (s, 2H).

Synthesis of (1,3-dimethylbutyl)-N′-p-hydroxyphenyl-p-phenylenediamine (inventive compound of formula I)) according to step e1)

[0171] ##STR00016##

[0172] 0.31 g (1.55 mmol, 1 eq.) of N-p-hydroxyphenyl-p-phenylenediamine, 0.66 g of palladium on carbon (5%) (0.2 g on 4.67 mmol of substrate) and 20.0 mL of methyl isobutyl ketone were weighed into a stainless steel autoclave fitted with a Teflon innerliner. The autoclave was then pressurized to 20 bar with hydrogen and stirred at 60° C. for 10 hours. After termination of the reaction, the excess hydrogen was blown off and the suspension filtered through diatomaceous earth (Celite®) and washed with ethanol. The filtrate was concentrated to dryness and dried under vacuum. According to NMR analysis, the crude product contains 70% of the target molecule.

[0173] The inventive compound of formula I) exhibits an elevated reactivity relative to 6PPD. This was consistent for example with the calculation of binding dissociation energies (BDE), and the free activation enthalpy Δ.sub.RG.sup.≠ and the free standard reaction enthalpy Δ.sub.RG.sup.○ for the reaction with a methyl peroxide radical. The values are reported in table 1. FIGS. 1a and 1b show the cleavage mechanisms to which the values relate:

TABLE-US-00001 TABLE 1 BDE Δ.sub.RG.sup.O Δ.sub.RG.sup.≠ Molecule [kJ/mol] [kJ/mol] [kJ/mol] 6PPD 313 −25.6 19.1 Formula I) 305 −28.8 16.0

[0174] As is apparent from table 1, the inventive compound of formula I) exhibits a lower bond dissociation energy and lower free enthalpies.

[0175] The compound of formula I) thus makes it possible to achieve an improved protective effect in the recited applications.

[0176] For use in a rubber mixture for vehicle tires, the inventive compound of formula I) is added for example instead of the aging stabilizers known in the prior art, such as 6PPD, 7PPD or IPPD etc., in a manner known to those skilled in the art in one of the mixing stages in the production of the rubber mixture.