Metal deactivators, or metal passivators, and antioxidants, the utility of the two are ultimately to slow down the process of oil oxidation, but the pathway of intervention and the principle of the role of the difference is very big, due to the metal, especially the copper metal, in the very early days has been proved, even if trace amounts of copper can also cause gasoline oxidation induced by the reduction of the period, so there are also known as metal passivation for the anticatalytic additives.

At present, the classification of petroleum additives will be metal deactivator into the lubricating oil additives, while the metal passivator into the fuel oil additives, lubricating oil in the process of use, in the presence of oxygen conditions, by the role of heat Yao light and oxidation and deterioration, at this time, if the oil contains copper Yao iron and other metal ions, even if the content is very low, they can also be on the oxidation of oil in the process of the radical chain reaction to accelerate the acceleration of the reaction, thereby accelerating the speed of oil oxidation. The oxidation speed of the oil is accelerated.

Mechanism of action of metal deactivators

Metal deactivators are lubricant additives that inhibit the catalytic effect of metals on oxidation and corrosion.

It has two mechanisms of action

    Film-forming effect, i.e. to generate a chemical film on the metal surface, preventing the metal and its ions from entering the oil and weakening its catalytic oxidizing effect on the oil.

    Chelation, that is, with the metal and its ions to generate a stable chelate, or with the precipitation of metal ions to generate insoluble substances, the catalytic activity of the metal ions to mask the role of the two mechanisms can be summarized as the formation of the metal deactivator to prevent the catalytic oxidation and corrosion of the anode and cathodic reaction of the inert blocking film, through the inhibition of corrosion, the metal deactivator also prevents the oxidation of the metal ions to promote the generation of the metal ions. Metal deactivator molecules, through its polar end to establish an inert barrier film, adsorption on the metal surface, and lipophilic end and lubricating oil fusion, metal deactivator varieties, benzotriazole and benzotriazole derivatives, said thiadiazole and thiadiazole derivatives, said the heterocyclic compounds.

Mechanism of action of antioxidants

Antioxidant is a kind of chemical that can improve the antioxidant performance of oil and prolong its use or storage life, also known as oxidation inhibitor. As we all know, oxidation reaction is ubiquitous, lubricants are no exception, lubricants and oxygen in the air in contact with certain environments, the temperature of its oxidation potential is almost 100%, if coupled with the catalytic metal oxidation rate increased dramatically, the free radical chain reaction of the oil is irreversible, these free radicals further reaction with hydrocarbons to generate alcohols Yao Aldehyde Yaohua Ketone and water and other substances, such as not inhibited or blocked, the oxidation of oil will continue until the overall oil is oxidized and corrupted. If not inhibited or blocked, the oxidation of the oil will continue until the whole oil is oxidized and corrupted, and is completely obsolete.

Therefore, there is a need for additives that can inhibit or block the oxidation of oil. Antioxidants can be classified into two main categories

    Antioxidants that can consume peroxide radicals and block the chain reaction, also known as free radical scavengers or chain terminators, usually called the main antioxidant.

    Antioxidants that decompose hydroperoxides, also known as hydroperoxide decomposers, are usually called secondary antioxidants. are also called hydroperoxide decomposers and are often called secondary antioxidants.