Organophosphorus compounds are one of the important lubricating oil additives. Phosphorus additives have excellent anti-wear effect when contacting with rough friction surfaces and slowly sliding metal surfaces. For example, tributyl phosphite and triphenyl phosphite are effective antioxidants for many petroleum based lubricants. In addition to good wear resistance and reduction performance, acid lauryl phosphite has good thermal stability, corrosion resistance and wear resistance. Phosphite can eliminate peroxyradical and alkoxyradical and inhibit photodegradation. Phosphite is not only an important antioxidant, but also an antiwear agent with outstanding performance. Phosphoric amine is a multi-functional additive with good anti-corrosion, anti-wear and anti-friction properties. It is widely used in industrial oil, grease and vehicle gear oil. Due to the strong polarity of phosphoric amine, it is easy to react with other additives.
The most important feature of organic sulfur antioxidants is that they can be used as acid catalytic decomposition agents to eliminate peroxides and react with hydroperoxides to form sulfones or sulfoxides, which are relatively stable. Some aromatic and aliphatic sulfides can also be used to inhibit the oxidation and corrosion of oil products. In addition, alkyl phenol sulfide also has a very good antioxidant performance. Metal can be used to treat the hydroxyl group in alkyl phenol sulfide to form oil-soluble metal phenols, which play a dual role of detergents and antioxidants. Sulfur compounds derived from -thiodiols are antioxidants in automatic transmission fluids.