Ethyl silicone oil (ethyl siloxane fluid), chemically known as polydiethylsiloxane, is an organosilicon compound with excellent chemical stability. Its chemical stability is detailed below from several aspects:

Basic Chemical Properties
The molecular formula of ethyl silicone oil is C4n+12H3O+10nSin+2On+1, CAS number is 63148-61-8, and it is also known as polydiethylsiloxane or diethyl silicone oil. It is a pale yellow liquid with the following basic properties:

Melting point: <-40°C
Boiling point: >205°C
Density: 0.96 g/cm³
Refractive index: 1.438
Flash point: 80°C
Form: Liquid
Specific gravity: 0.913
Ethyl silicone oil's main chain is composed of silicon and oxygen atoms, with ethyl groups attached to the silicon side groups. Its viscosity at 20°C ranges from 8-1000 mm²/s, and its relative density is 0.95-1.06. It is a colorless, transparent oil.

Chemical Environmental Stability
Ethyl silicone oil exhibits good stability in various chemical environments:

Acid stability: Ethyl silicone oil possesses excellent chemical stability, maintaining its structural and property stability in complex chemical environments and not easily reacting with other substances.

Alkali stability: Various ethylethoxysilanes can be hydrolyzed and condensed in the presence of hydrochloric acid to form polysiloxanes, which can then be rearranged to obtain ethyl silicone oil.

Oxidation Stability: Ethyl silicone oil possesses antioxidant properties, low vapor pressure, and is non-corrosive to metals. It does not easily deteriorate with prolonged exposure to air at 150℃, and its oxidation is also slow when exposed to oxygen at 200℃.

Thermal Stability: Ethyl silicone oil exhibits excellent thermal stability:
Long-term operating temperature range: -70℃ to 150℃

It maintains relatively stable performance at high temperatures and retains its basic properties within the normal operating temperature range (150-200℃)

It does not easily deteriorate with prolonged exposure to air at 150℃, and its oxidation is also slow when exposed to oxygen at 200℃

It has good waterproof properties, chemical corrosion resistance, a small temperature coefficient, and low vapor pressure. Ethyl silicone oil has a wide range of downstream applications, mainly in industry, cosmetics, and pharmaceuticals.

Reaction Characteristics of Ethyl Silicone Oil to Common Chemical Reagents:
Similar to methyl silicone oil, but with higher lubrication performance and better solvent resistance
It is miscible with mineral lubricating oils

In chloroform, Soluble in small amounts in solvents such as ethyl acetate and toluene. Insoluble in water, methanol, ethylene glycol, and 2-ethoxyethanol. Miscible with benzene, dimethyl ether, methyl ethyl ketone, carbon tetrachloride, or kerosene. Slightly soluble in acetone, dioxane, ethanol, and butanol. Easily soluble in benzene, toluene, xylene, diethyl ether, and chloroalkanes.

Applications: Due to its excellent chemical stability, ethyl silicone oil is widely used in:
Precision instrument lubrication
Hydraulic oil
Mold release agents
Defoamers
Cosmetics
Pharmaceutical products
High-temperature lubricants
High-temperature sealants, etc.

In summary, ethyl silicone oil exhibits good stability in chemical environments such as acids, alkalis, and oxidants, and possesses excellent thermal stability and solvent resistance. These properties make it widely used in various fields such as industry, cosmetics, and pharmaceuticals.