Liquid octylated phenyl-α-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 consisting 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, 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.

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

3. The blend of claim 2, wherein the octylated phenyl-α-naphthylamine is present at about 30% by weight of the blend.

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

5. The blend of claim 2, 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.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) 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%.

(2) 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

(3) 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. %.

(4) 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 %.

(5) 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%.

(6) 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.

(7) 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.

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

(9) 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

(10) 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 —
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).

(11) 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.