Azaphenothiazines and azaphenoxazines as antioxidants
Inventors
Pratt, Derek Andrew • HAIDASZ, Evan
Assignees
Publication Number
US-11512262-B2
Publication Date
2022-11-29
Expiration Date
2038-03-15
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Abstract
The present disclosure relates generally to antioxidants. More particularly, the present disclosure relates to lubricating compositions comprising an antioxidant.
Core Innovation
The present disclosure relates generally to antioxidants, particularly to novel compounds including azaphenothiazines and azaphenoxazines, which serve as antioxidants in lubricating compositions. The invention provides various compounds of specified Formulae containing nitrogen atoms in the aromatic ring structures, sulfur or oxygen atoms, and electron donating groups designed to improve antioxidant properties. These compounds are incorporated into lubricating oils to stabilize the oils against oxidative degradation.
The problem being addressed by this invention is the oxidative degradation of organic substrates, particularly lubricating oils used in combustion engines and other applications. Oxidation reduces the lubricating capacity by increasing viscosity, forming deposits, and leading to wear of engine parts. Existing antioxidants may not sufficiently prevent degradation at high engine operating temperatures. Therefore, there remains a need for effective antioxidants capable of retarding oxidation in lubricants to increase their stability and lifespan.
The invention addresses this problem by providing specific antioxidant compounds characterized by structures with multiple nitrogen atoms in the aromatic rings, sulfur or oxygen heteroatoms, and electron donating groups. These antioxidants can be used in lubricating compositions that include natural or synthetic oils, optionally with other performance additives, to enhance oxidation resistance and performance of the lubricants, especially under conditions of elevated temperatures typical of combustion engines.
Claims Coverage
The patent includes eight main inventive features covered by independent claims, relating to lubricant compositions, methods of forming such compositions, kits, and methods of using the compositions for engine lubrication.
Lubricant composition comprising oil and specific antioxidant compounds
A lubricant composition useful for engines comprising an oil of lubricating viscosity and a compound selected from a specified group of compounds of Formula (I) featuring azaphenothiazine and azaphenoxazine derivatives.
Method of forming lubricant composition by combining oil and antioxidant compound
A method of forming a lubricant composition useful for engines comprising combining an oil of lubricating viscosity with a compound of Formula (I) from the specified group.
Kit comprising lubricant composition with oil and antioxidant compound
A kit comprising the lubricant composition as described, including an oil of lubricating viscosity and a compound from the specified group of compounds of Formula (I).
Lubricating a combustion engine using lubricant compositions with specified antioxidants
A method of lubricating a combustion engine, comprising applying a lubricant composition comprising an oil of lubricating viscosity and a compound selected from the group consisting of compounds of Formula (I).
Oil of lubricating viscosity comprising natural, synthetic, or mixed oils
The oil of lubricating viscosity used in the lubricant compositions can be natural oil, synthetic oil, or mixtures thereof, and includes API Group I through Group V base oils.
Lubricant compositions optionally comprising various additives
The lubricant composition may further include additives selected from metal deactivators, detergents, friction modifiers, antiwear agents, rust inhibitors, dispersants, viscosity index improvers, extreme pressure agents, additional antioxidants, foam inhibitors, pour point depressants, and seal swelling agents.
Method of forming lubricant compositions optionally including additives
The method of forming lubricant compositions includes optionally combining additives of the types mentioned to enhance properties.
Use of lubricant compositions at high engine operating temperatures
The lubricant compositions and methods are useful for engine operating temperatures of at least 100° C. or at least 160° C.
In summary, the claims broadly cover lubricant compositions comprising specified azaphenothiazine and azaphenoxazine antioxidant compounds in various oils, the methods of making and using these compositions for engine lubrication, optionally including multiple performance additives, and applicability at elevated engine temperatures.
Stated Advantages
The antioxidants provided improve the stability and lifespan of lubricating oils by retarding oxidation.
The compounds enhance lubricant performance at high engine operating temperatures (at least 100° C. or 160° C.).
The antioxidants effectively scavenge free radicals, reducing oil degradation and deposit formation, thereby diminishing engine wear.
The compositions allow for inclusion in a range of base oils including natural and synthetic oils from various API groups.
Documented Applications
Use as antioxidants in lubricating compositions for combustion engines.
Incorporation into lubricating oils for engine types including heavy duty diesel, passenger car, light duty diesel, medium speed diesel, marine, gasoline fueled, bio-fueled, natural gas fueled, hybrid, 2-stroke, 4-stroke, and rotary internal combustion engines.
Use in lubricants for engines having components made from aluminum-alloy, lead, tin, copper, cast iron, magnesium, ceramics, stainless steel, composites, and those with special coatings.
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