BENZAZEPINE COMPOUNDS AS ANTIOXIDANTS FOR LUBRICANT COMPOSITIONS

Abstract

A lubricating composition including an oil of lubricating viscosity and a benzazepine compound. Methods of using such lubricating compositions are also disclosed.

Claims

1. A lubricating composition comprising an oil of lubricating viscosity and a benzazepine compound.

2. The lubricating composition of claim 1, wherein the benzazepine compound is substituted with a second aryl ring that shares two carbon atoms with a nitrogen-containing ring of the benzazepine compound.

3. The lubricating composition of claim 1, wherein a nitrogen-containing ring of the benzazepine compound contains at least one additional heteroatom, wherein the heteroatom is at least one of oxygen, sulfur, or nitrogen.

4. The lubricating composition of claim 1, wherein the benzazepine compound is represented by at least one of the following general formulae IA or IB: ##STR00007## wherein R.sup.1, R.sup.2 and R.sup.3 are each independently hydrogen or a hydrocarbyl group of 1 to 24 carbon atoms, or R.sup.1 and R.sup.2 together form a saturated five- or six-membered carbon ring, an unsaturated five- or six-membered carbon ring, or an aromatic ring, any of which is optionally further substituted with a hydrocarbyl group of 1 to 24 carbon atoms; each X is independently O, S, or NR.sup.4; and R.sup.4 is hydrogen or a hydrocarbyl group of 1 to 18 carbon atoms.

5. The lubricating composition of claim 1, wherein the benzazepine compound comprises a dibenzazepine compound.

6. The lubricating composition of claim 5, wherein the dibenzazepine compound is represented by the at least one of the following general formulae IIA or IIB: ##STR00008## wherein R.sup.1, R.sup.2 and R.sup.3 are each independently hydrogen or a hydrocarbyl group of 1 to 24 carbon atoms; each X is independently O, S, or NR.sup.4; and R.sup.4 is hydrogen or a hydrocarbyl group of 1 to 18 carbon atoms.

7. The lubricating composition of claim 1, wherein the benzazepine compound is present in the lubricating composition in an amount 0.1 to 5.0 weight percent based on the total weight of the lubricating composition.

8. The lubricating composition of claim 1, wherein the lubricating composition comprises at least 0.3 weight percent of at least one additional lubricant additive comprising at least one of an ashless polyisobutenyl succinimide dispersant, an overbased or neutral metal-based detergent, an anti-wear agent, a polymeric viscosity modifier, or an ashless antioxidant different from the benzazepine compound.

9. The lubricating composition of claim 8, wherein the ashless polyisobutenyl succinimide dispersant is present in the lubricating composition in an amount of from 0.5 to 4.0 weight percent based on the total weight of the lubricating composition.

10. The lubricating composition of claim 8, wherein the metal-based detergent comprises at least one of a neutral alkaline earth metal detergent or an overbased alkaline earth metal detergent, in an amount of from 0.2 to 15 weight percent based on the total weight of the lubricating composition.

11. The lubricating composition of claim 10, wherein the at least one of a neutral alkaline earth metal detergent or an overbased alkaline earth metal detergent comprises at least one of an alkylbenzene sulfonate detergent, a sulfur-coupled phenate detergent, or an alkylsalicylate detergent.

12. The lubricating composition of claim 8, wherein at least one anti-wear agent is present in an amount of from 0.05 to 3 weight percent based on the total weight of the lubricating composition.

13. The lubricating composition of claim 12, wherein the at least one anti-wear agent comprises a phosphorus-containing compound in an amount effective to deliver 200 to 1200 ppm phosphorus to the lubricating composition.

14. The lubricating composition of claim 12, wherein the at least one anti-wear agent comprises a zinc dialkyl dithiophosphate.

15. The lubricating composition of claim 8, wherein the ashless antioxidant different from the benzazepine compound is present in an amount of from 0.01 to 5 weight percent based on the total weight of the lubricating composition.

16. The lubricating composition of claim 1, wherein the lubricating composition comprises less than 0.1 weight percent of a diarylamine antioxidant.

17. The lubricating composition of claim 1, wherein the lubricating composition is substantially free of a diarylamine antioxidant.

18. The lubricating composition of claim 1, wherein the benzazepine compound comprises at least one of: benzazepine; dihydro-benzazepine; tetrahydro benzazepine; 5H-dibenzo[b,f]azepine; 10,11-dihydro-5H-dibenzo[b,f]azepine; or hydrocarbyl-substituted derivatives thereof.

19. A method of lubricating an internal combustion engine comprising supplying to the internal combustion engine the lubricating composition of claim 1.

20. A method of improving the oxidative resistance of a crankcase lubricant, wherein the method comprises lubricating the crankcase with the lubricating composition of claim 1.

Description

EXAMPLES

[0121] The subject matter disclosed herein may be better understood with reference to the following examples, which are set forth merely to further illustrate the subject matter disclosed herein. The illustrative examples should not be construed as limiting the subject matter in any manner.

[0122] A series of benzazepine compounds were evaluated for their ability to reduce oxidative degradation of lubricating compositions. The procedure to alkylate commercially available selected benzazepine is described below, and examples of suitable (di)benzazepine compounds are summarized below (Table 1).

[0123] Example A (2,8-dinonyl-10,11-dihydro-5H-dibenzo[b,f]azepine): A 1 L, 4-neck flask was equipped with an overhead stirrer, nitrogen subsurface tube supplying 0.1 cfh N.sub.2, and a Dean-Stark trap topped with a water condenser. To the flask was charged propylene trimer (182 g, 1.46 mol). The flask was heated to 85 C. and 10,11-dihydro-5h-dibenzo[b,f]azepine (95 g, 487 mmol) was then charged and slurried in the flask. The reaction was further heated to 100 C. and acidic clay (28.5 g) was then charged. The reaction was heated to reflux at 150 C. and held for 12 h. The reaction was filtered through diatomaceous earth and then stripped of residual olefin at 170 C. The reaction was again filtered to provide the product as a viscous yellow oil (91.1 g, 41.8%). % N3.4%, TBN125 mg KOH/g material.

[0124] Example B (2,8-bis(4,6-dimethylheptan-2-yl)-5H-dibenzo[b,f]azepine): A 1 L, 4-neck flask was equipped with an overhead stirrer, N.sub.2 line, thermowell, and a Friedrich condenser. 5H-dibenzo[b,f]azepine (100 g, 512 mmol) and acetic anhydride were charged into the flask and heated to 125 C. After 4 h, the volatiles were removed via vacuum stripping. Propylene trimer (196 g, 1.55 mol) was charged to the flask and the material was heated to 80 C. Aluminum trichloride was then charged and the reaction was heated to and held at 150 C. for 9 hours. The reaction was cooled to 80 C. and 10 g of water was slowly added followed by 170 g of 45% KOH solution (aq.). The mixture was heated and held at 110 C. for 7 hours then left to phase separate. The aqueous layer was drained and the organic layer was stripped to remove excess propylene trimer. Upon cooling the product solidified into a brown solid (113 g, 93%). % N5.9%.

[0125] Tables 1A and 1B below present illustrative benzazepine compounds according to the present subject matter, made similarly to Example A/Example B above, in reference to one of the following Structure I or Structure II (in Table 1A, (B) refers to a branched hydrocarbyl group and (L) refers to a linear hydrocarbyl group):

##STR00006##

TABLE-US-00003 TABLE 1A Structure Example X R.sub.1 R.sub.2 R.sub.3 R.sub.4 I A CH.sub.2 C.sub.9H.sub.19 (B) H C.sub.9H.sub.19 (B) H II B CH C.sub.9H.sub.19 (B) H C.sub.9H.sub.19 (B) H I C CH.sub.2 C.sub.10H.sub.21 (L) H C.sub.10H.sub.21 (L) H I D CH.sub.2 C.sub.9H.sub.19 (B) H C.sub.9H.sub.19 (B) CH.sub.2CHCH.sub.2 I E CH.sub.2 C.sub.9H.sub.19 (B) C.sub.9H.sub.19 (B) C.sub.9H.sub.19 (B) H I F CH.sub.2 C.sub.9H.sub.19 (B) H C.sub.9H.sub.19 (B) CH.sub.3 I G CH.sub.2 C.sub.12H.sub.25 (B) H C.sub.12H.sub.25 (B) H II H CH C.sub.12H.sub.25 (B) H C.sub.12H.sub.25 (B) H I I NH C.sub.9H.sub.19 (B) H C.sub.9H.sub.19 (B) H I J O C.sub.9H.sub.19 (B) H C.sub.9H.sub.19 (B) H II K N C.sub.9H.sub.19 (B) H C.sub.9H.sub.19 (B) H

TABLE-US-00004 TABLE 1B Structure Example IUPAC I A 2,8-bis(4,6-dimethylheptan-2-yl)- 10,11-dihydro-5H-dibenzo[b,f]azepine II B 2,8-bis(4,6-dimethylheptan-2-yl)- 5H-dibenzo[b,f]azepine I C 2,8-di(nonan-2-yl)-10,11-dihydro- 5H-dibenzo[b,f]azepine I D 5-allyl-2,8-bis(4,6-dimethylheptan- 2-yl)-10,11-dihydro-5H-dibenzo[b,f]azepine I E 2,4,8-tris(4,6-dimethylheptan-2-yl)- 10,11-dihydro-5H-dibenzo[b,f]azepine I F 2,8-bis(4,6-dimethylheptan-2-yl)-5- methyl-10,11-dihydro-5H-dibenzo[b,f]azepine I G 2,8-bis(4,6,8-trimethylnonan-2-yl)- 10,11-dihydro-5H-dibenzo[b,f]azepine II H 2,8-bis(4,6,8-trimethylnonan-2-yl)- 5H-dibenzo[b,f]azepine I I 2,8-bis(4,6-dimethylheptan-2-yl)- 10,11-dihydro-5H-dibenzo[b,e][1,4]diazepine I J 2,8-bis(4,6-dimethylheptan-2-yl)- 5,11-dihydrodibenzo[b,e][1,4]oxazepine II K 2,8-bis(4,6-dimethylheptan-2-yl)- 5H-dibenzo[b,e][1,4]diazepine

[0126] Lubricating compositions: A series of 5W-30 lubricant compositions were prepared with the various benzazepine compounds described herein as well as conventional crankcase additives such as ashless polyisobutenylsuccinimide dispersant, overbased alkaline earth metal detergent, zinc dialkyl dithiophosphate (ZDDP), additional ashless antioxidant, polymeric viscosity modifiers, and other common additives, as shown in Table 2.

TABLE-US-00005 TABLE 2.sup.1 EX1 EX2 EX3 EX4 EX5 EX6 Group III Base Oil Balance to 100% Nonylated diphenylamine 0 0.8 1.5 0 0 0 Example A 0 0 0 0.8 1.5 0 Example B 0 0 0 0 0 0.8 PIBsuccinimide Dispersant.sup.2 2.9 2.9 2.9 2.9 2.9 2.9 Borated PIBsuccinimide Dispersant.sup.3 2.85 2.85 2.85 2.85 2.85 2.85 Magnesium Sulfonate.sup.4 0.29 0.29 0.29 0.29 0.29 0.29 Calcium Salicylate.sup.5 1.1 1.1 1.1 1.1 1.1 1.1 ZDDP - secondary C3/C6 0.73 0.73 0.73 0.73 0.73 0.73 Sulfurized olefin 0.5 0.5 0.5 0.5 0.5 0.5 Oxyalkylated phenol 2 2 2 2 2 2 Styrene-diene VM 0.54 0.54 0.54 0.54 0.54 0.54 Other Additives.sup.6 0.2 0.2 0.2 0.2 0.2 0.2 Calcium (ppm) 1180 1220 1220 1220 1220 1230* Magnesium (ppm) 460 490 480 480 480 470* Phosphorus (ppm) 740 830 835 840 860 800* Sulfur (ppm) 2270 2550 2580 2620 2680 2600* Kinematic Viscosity (100 C.) 9.73 9.80 9.84 9.81 9.89 9.8* *Calculated value .sup.1All treat rates are oil free, unless otherwise indicated .sup.2Polyisobutenyl succinimide made from high vinylidene PIB (TBN 26 mg KOH/g) .sup.3Borated polyisobutenyl succinimide made from high vinylidene PIB (TBN 27 mg KOH/g; 0.8% B) .sup.4Overbased magnesium alkylbenzene sulfonate (TBN 700 mg KOH/g) .sup.5Overbased calcium alkylsalicylate (TBN 300 mg KOH/g) .sup.6Other additives include pourpoint depressant and foam inhibitor

[0127] Oxidation resistance was evaluated by determining oxidation inhibition times using pressure differential scanning calorimetry (CEC L85), deposit formation with the Komatsu hot tube test (KHT), MHT TEOST (ASTM D7097), Micro-coker test (MCT) and oxidative stability in the presence of biodiesel (according to ACEA 2016: CEC L109). Relative performance of azepine derivatives in tests were compared to antioxidant free and alkylated diphenylamine containing formulations, as shown in Table 3.

[0128] The MCT involves placing 0.6 mL of the lubricating composition in the trough of an aluminum-alloy plate heated at one end (hot spot) and regulated at the other end (cold spot). At the end of the test, the deposit formation is determined and rated on a scale of 1-10 according to the CEC M-02-A-78 Code of Practice. Higher ratings indicate better deposit performance.

[0129] KHT measures the deposit formation tendency of the lubricating composition at high temperature conditions. In KHT, high rating means better deposit control performance. The KHT test employs heated glass tubes through which a sample lubricating composition is pumped (5 mL total sample), at 0.31 mL/hour for 16 hours, with an air flow of 10 mL/minute. The glass tube is rated at the end of test for deposits on a scale of 0 (very heavy varnish) to 10 (no varnish).

TABLE-US-00006 TABLE 3 EX1 EX2 EX3 EX4 EX5 EX6 PDSC - Oxidation Induction Time (min) [CEC L85] 41 119 174 119 161 nd Hot Tube Rating (@280 C.) 0 7 7 7 7 nd L109 - Oxidation @ 216 hr 61 37 29 37 32 nd L109 - KV100 @ 216 hr (m.sup.2/s) 151 41 32 67 59 nd MHT TEOST - Total Deposits (mg) 42.3 22.2 11.5 23.6 13.5 nd MCT Panel (Merit) 7.7 9 9.2 8.8 9.2 nd

[0130] Except in the Examples, or where otherwise explicitly indicated or required by context, all numerical quantities in this description specifying amounts of materials, reaction conditions, molecular weights, number of carbon atoms, and the like, are to be understood as modified by the word about. As used herein, the term about means that a value of a given quantity is within 20% of the stated value. In other embodiments, the value is within 15% of the stated value. In other embodiments, the value is within 10% of the stated value. In other embodiments, the value is within 5% of the stated value. In other embodiments, the value is within 2.5% of the stated value. In other embodiments, the value is within 1% of the stated value. In other embodiments, the value is within a range of the explicitly-described value which would be understood by those of ordinary skill, based on the disclosures provided herein, to perform substantially similarly to compositions including the literal amounts described herein.

[0131] It is to be understood that the upper and lower amount, range, and ratio limits set forth herein may be independently combined, and that any amount within a disclosed range is contemplated to provide a minimum or maximum of a narrower range in alternative embodiments (with the proviso, of course, that the minimum amount of a range must be lower than the maximum amount of the same range). Similarly, the ranges and amounts for each element of the subject matter disclosed herein may be used together with ranges or amounts for any of the other elements.

[0132] The present disclosure is not to be limited in terms of the particular embodiments described in this application, which are intended as illustrations of various aspects. Many modifications and variations can be made without departing from its spirit and scope, as will be apparent to those skilled in the art. Functionally equivalent methods and components within the scope of the disclosure, in addition to those enumerated herein, will be apparent to those skilled in the art from the foregoing descriptions. Such modifications and variations are intended to fall within the scope of the appended claims. The present disclosure is to be limited only by the terms of the appended claims, along with the full scope of equivalents to which such claims are entitled. It is to be understood that this disclosure is not limited to particular methods, reagents, compounds, or compositions, which can, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting.