Hexamethylcyclotrisiloxane

Hexamethylcyclotrisiloxane (also known as D3 or HMTS) is an organic compound with the formula ((CH3)2SiO)3. It is a colorless liquid that is used as a monomer in the production of polydimethylsiloxane (PDMS), a type of silicone polymer.

Structure and properties[edit | edit source]

Hexamethylcyclotrisiloxane is a cyclic compound, consisting of three silicon atoms and three oxygen atoms arranged in a ring. Each silicon atom is also bonded to two methyl groups. This structure gives the compound its unique properties, including its low boiling point and high volatility.

The compound is a clear, colorless liquid at room temperature. It has a boiling point of 134°C and a density of 0.958 g/cm3. It is soluble in many organic solvents, but not in water.

Production and uses[edit | edit source]

Hexamethylcyclotrisiloxane is produced by the hydrolysis of dimethyldichlorosilane, followed by distillation to separate it from other products.

The primary use of hexamethylcyclotrisiloxane is as a monomer in the production of polydimethylsiloxane. This is achieved through a process known as ring-opening polymerization, in which the cyclic structure of the monomer is broken and the resulting linear molecules are linked together to form a polymer.

Polydimethylsiloxane is a versatile material with a wide range of applications. It is used in the manufacture of silicone rubber, silicone oil, and silicone resin. It is also used in cosmetics, medical devices, and as a lubricant.

Safety and environmental considerations[edit | edit source]

Hexamethylcyclotrisiloxane is generally considered to be of low toxicity. However, it can cause irritation to the eyes, skin, and respiratory tract if exposure is high. It is also classified as a Volatile Organic Compound (VOC), and its release into the environment can contribute to air pollution.