LIQUID OCTYLATED PHENYL-ALPHA-NAPHTHYLAMINE COMPOSITION

Abstract

A liquid blend of octylated phenyl-α-naphthylamine, and at least one low molecular weight aromatic ester, wherein the octylated phenyl-α-naphthylamine is present from about 15% to about 35% by weight of the blend, as well as a lubricating composition comprising a lubricant base and an amount of the blend which provides up to 2.0% by weight of the octylated phenyl-α-naphthylamine in the composition.

Claims

1. A liquid blend comprising octylated phenyl-α-naphthylamine, and at least one low molecular weight aromatic ester, wherein the octylated phenyl-α-naphthylamine is present from about 15% to about 35% by weight of the blend.

2. The blend of claim 1, wherein the aromatic ester is chosen as one or more in combination of tris-methyl trimellitate, tris-ethyl trimellitate, tris-propyl trimellitate, tris-butyl trimellitate, tris-2-ethylhexyl trimellitate, tris-isooctyl trimellitate, tris-2-ethylhexyl trimellitate, tris-n-octyl trimellitate, tris-isononyl trimellitate, tris-isodecyl trimellitate, diethyl phthalate, dipropyl phthalate, dibutyl phthalate, di-2-ethylhexyl phthalate, diisooctyl phthalate, di-n-octyl phthalate, diisononyl phthalate, diisodecyl phthalate, diethyl isophthalate, dipropyl isophthalate, dibutyl isophthalate, di-2-ethylhexyl isophthalate, diisooctyl isophthalate, di-n-octyl isophthalate, diisononyl isophthalate, diisodecyl isophthalate, diethyl terephthalate, dipropyl terephthalate, dibutyl terephthalate, di-2-ethylhexyl terephthalate, diisooctyl terephthalate, di-n-octyl terephthalate, diisononyl terephthalate, diisodecyl terephthalate, 2-ethylhexyl benzoate, isooctyl benzoate, n-octyl benzoate, isodecyl benzoate, methyl trans-cinnamate, and benzyl benzoate.

3. The blend of claim 1, wherein the octylated phenyl-α-naphthylamine is present from about 25% to about 32% by weight of the blend.

4. The blend of claim 3, wherein the octylated phenyl-α-naphthylamine is present at about 30% by weight of the blend.

5. The blend of claim 1, wherein the aromatic ester is chosen from benzyl benzoate, diethyl phthalate and a combination thereof.

6. The blend of claim 3, wherein the aromatic ester is chosen from benzyl benzoate, diethyl phthalate and a combination thereof.

7. The blend of claim 4, wherein the aromatic ester is chosen from benzyl benzoate, diethyl phthalate and a combination thereof.

8. A lubricating composition comprising a lubricant base at 85% or more by weight of the lubricating composition, and a liquid blend comprising octylated phenyl-α-naphthylamine and at least one aromatic ester, wherein the octylated phenyl-α-naphthylamine is present from about 15% to about 35% by weight of the blend, and the blend is present in the lubricating composition in an amount which provides from about 0.01 to about 1.0 weight percent of octylated phenyl-α-naphthylamine in the lubricating composition.

9. The lubricating composition of claim 8, wherein the octylated phenyl-α-naphthylamine is present from about 25% to about 32% by weight of the blend.

10. The lubricating composition of claim 9, wherein the octylated phenyl-α-naphthylamine is present from at about 30% by weight of the blend.

11. The lubricating composition of claim 8, wherein the blend is present in the lubricating composition in an amount which provides from about 0.05 to about 0.2 weight percent of octylated phenyl-α-naphthylamine in the lubricating composition.

12. The lubricating composition of claim 9, wherein the blend is present in the lubricating composition in an amount which provides from about 0.05 to about 0.2 weight percent of octylated phenyl-α-naphthylamine in the lubricating composition.

13. The lubricating composition of claim 10, wherein the blend is present in the lubricating composition in an amount which provides from about 0.05 to about 0.2 weight percent of octylated phenyl-α-naphthylamine in the lubricating composition.

14. The lubricating composition of claim 8, wherein the aromatic ester is chosen from one or more in combination of tris-methyl trimellitate, tris-ethyl trimellitate, tris-propyl trimellitate, tris-butyl trimellitate, tris-2-ethylhexyl trimellitate, tris-isooctyl trimellitate, tris-2-ethylhexyl trimellitate, tris-n-octyl trimellitate, tris-isononyl trimellitate, tris-isodecyl trimellitate, diethyl phthalate, dipropyl phthalate, dibutyl phthalate, di-2-ethylhexyl phthalate, diisooctyl phthalate, di-n-octyl phthalate, diisononyl phthalate, diisodecyl phthalate, diethyl isophthalate, dipropyl isophthalate, dibutyl isophthalate, di-2-ethylhexyl isophthalate, diisooctyl isophthalate, di-n-octyl isophthalate, diisononyl isophthalate, diisodecyl isophthalate, diethyl terephthalate, dipropyl terephthalate, dibutyl terephthalate, di-2-ethylhexyl terephthalate, diisooctyl terephthalate, di-n-octyl terephthalate, diisononyl terephthalate, diisodecyl terephthalate, 2-ethylhexyl benzoate, isooctyl benzoate, n-octyl benzoate, isodecyl benzoate, methyl trans-cinnamate, and benzyl benzoate.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] FIGS. 1-4 are line graphs depicting a thermogravimetric analysis of the liquid blend for determining mass loss with respect to temperature for benzyl benzoate and diethyl phthalate blended with octylated N-phenyl-α-naphthylamine at 30%.

[0010] FIGS. 5-7 are bar graphs showing relative oxidation of a lubricating composition comprising a different base oils and the inventive blends of octylated N-phenyl-α-naphthylamine/benzyl benzoate and octylated N-phenyl-α-naphthylamine/diethyl phthalate.

DETAILED DESCRIPTION OF THE INVENTION

[0011] Octylated N-phenyl-α-naphthylamine (available as VANLUBE® 1202 antioxidant from Vanderbilt Chemicals, LLC of Norwalk, Conn.) is blended with a low molecular weight aromatic ester at about 20 degrees C. The esters are preferably benzyl benzoate, diethyl phthalate or a mixture of the two. However, it is expected that any of the aromatic esters listed earlier in the specification could be effective for the stated purpose, namely, providing a stable, liquid environment for octylated N-phenyl-α-naphthylamine. The amount of octylated N-phenyl-α-naphthylamine in the blend will range from about 15 to about 35 weight percent, preferably about 25-32 wt. %, more preferably about 28-32 wt. %, and most preferably about 30 wt. %.

[0012] The invention also relates to a lubricating composition comprising a lubricating base of at least 85% by weight, and a blend of APANA, preferably octylated N-phenyl-α-naphthylamine and aromatic ester in an amount which provides from about 0.01 to about 1.0% of APANA in the lubricating composition, preferably about 0.05 to about 0.2 weight %.

[0013] Test samples were prepared with VANLUBE® 1202 octylated N-phenyl-α-naphthylamine (also labeled as VL 1202 in the figures) at 30% and 40% by weight of the total octylated N-phenyl-α-naphthylamine/ester blend in diethyl phthalate. 30% octylated N-phenyl-α-naphthylamine in diethyl phthalate showed good storage stability after 46 days. 30% octylated N-phenyl-α-naphthylamine diethyl phthalate. 40% octylated N-phenyl-α-naphthylamine in diethyl phthalate showed crystal fallout after 13 days, suggesting that 40% octylated N-phenyl-α-naphthylamine is too high to achieve stability and therefore the acceptable limit is below 40%.

[0014] Liquid samples of 30% and 40% octylated N-phenyl-α-naphthylamine were made in 1:1 (by weight) benzyl benzoate:diethyl phthalate solvent mixture. 30% octylated N-phenyl-α-naphthylamine sample in 1:1 benzyl benzoate and diethyl phthalate showed good stability after 76 days. Table 1 below shows the results for the 30% and 40% blends in terms of stability.

TABLE-US-00001 TABLE 1 Stability Stability (room (dark - away temperature from direct Sample # APANA Diluent (s) 18-25 C.) sun light) SWD 689-66 30% Diethyl phthalate Clear after 113 days SWD 689-74 30% Diethyl phthalate Clear after 98 days SWD 689-67 40% Diethyl phthalate Crystals after 13 days SWD 689-72 30% Benzyl benzoate Clear after and diethyl 98 days phthalate (1:1) SWD 689-73 40% Benzyl benzoate Crystals after and diethyl 12 days phthalate (1:1) RTJ 683-113 30% Benzyl benzoate Clear after *Reconstituted 70 days RTV *sample stored cold to simulate variable storage temperatures, then gently heated to redissolve. Room temperature stability was confirmed.
Sample RTJ 683-113 that was kept in a refrigerator showed crystal fall out. However, upon gently heating to 50 degrees C., the solid component dissolved completely and remained clear after 70 days at room temperature.

[0015] Table 2 below shows analytic analysis for the 30% octylated N-phenyl-α-naphthylamine (OPANA) blends

TABLE-US-00002 TABLE 2 SWD 689-61 SWD 689-66 (OCD-462) (OCD-462B) SWD 689-72 30% OPANA in 30% OPANA in 30% OPANA in benzyl benzoate diethyl phthalate (1:1) BB Property (BB) (DEP) and DEP ASTM color 5 3.5 4 Density 1.092 1.092 1.092 @20 C. Flash Point C. 167 156 160 (closed cup) Viscosity at 14.8 19 15.25 40 C. cSt Viscosity at 1.1 2.4 0.877 100 C. cSt

TABLE-US-00003 TABLE 3 ONSET TEMP 1 ONSET TEMP 2 SAMPLE (° C.) (° C.) SWD-689-61 OCD-462, 166.8 263.7 30% OPANA in benzyl benzoate SWD-689-66 OCD-462B, 138.9 240.5 30% OPANA in diethyl phthalate Benzyl Benzoate 154.1 — Diethyl phthalate 147.1 —

[0016] With reference to FIGS. 1-4 and Table 3 above, a thermogravimetric analysis (TGA) was done to assess volatility, being measured in terms of weight loss to determine the onset temperature at which the blend becomes volatile. A higher onset temperature is preferable. TGA of SWD-689-61 (benzyl benzoate) sample showed better volatility compared to SWD-689-66 (diethyl phthalate).

[0017] With reference to FIGS. 5-7, samples of the octylated N-phenyl-α-naphthylamine/benzyl benzoate and octylated N-phenyl-α-naphthylamine/diethyl phthalate (both at 30% octylated N-phenyl-α-naphthylamine within the blend) were added to Group I and II base oils at treat rates of 0.05, 0.1 and 0.2 weight % octylated N-phenyl-α-naphthylamine and were evaluated for antioxidant activity by means of RPVOT (The Rotating Pressure Vessel Oxidation Test) and PDSC (Pressure Differential Scanning calorimetry). These data demonstrate that blends of octylated N-phenyl-α-naphthylamine/aromatic esters are within a range of acceptance in terms of antioxidant protection when compared to using octylated N-phenyl-α-naphthylamine on its own. However, given the ease of handling the inventive blend compared to the solid octylated N-phenyl-α-naphthylamine demonstrates that the blend is an advantageous substitute for solid octylated N-phenyl-α-naphthylamine.