2,4,6,8-Tetramethylcyclotetrasiloxane
[CAS# 2370-88-9]

Identification

• Classification: Chemical reagent >> Organic reagent >> Siloxane
• Name: 2,4,6,8-Tetramethylcyclotetrasiloxane
• Molecular Formula: C₄H₁₆O₄Si₄
• Molecular Weight: 240.51
• CAS Registry Number: 2370-88-9
• EC Number: 219-137-4
• SMILES: C[Si]1O[Si](O[Si](O[Si](O1)C)C)C

Properties

• Density: 0.9912 g/mL (Expl.)
• Melting point: -69 °C (Expl.)
• Boiling point: 134.5±0.0 °C (760 mmHg), Calc.^*, 134-135 °C (Expl.)
• Refractive index: 1.387 (Expl.)
• Flash point: 31.5±18.7 °C, Calc.^*, 25 °C (Expl.)

^* Calculated using Advanced Chemistry Development (ACD/Labs) Software.

Safety Data

• Hazard Symbols: GHS02 Warning
• Risk Statements: H226
• Safety Statements: P210-P233-P240-P241-P242-P243-P280-P303+P361+P353-P370+P378-P403+P235-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Flammable liquids	Flam. Liq.	3	H226
Eye irritation	Eye Irrit.	2	H319
Substances or mixtures which in contact with water emit flammable gases	Water-react.	1	H260

• Transport Information: UN 1993

Discovery and Applications

2,4,6,8-Tetramethylcyclotetrasiloxane, commonly known as TMCTS, is an important cyclic siloxane compound that finds extensive use in various industrial applications. This compound consists of a four-membered siloxane ring with four methyl groups attached to the silicon atoms. Its unique molecular structure imparts valuable properties, including low viscosity, high volatility, and good thermal stability, making it ideal for use in formulations requiring these characteristics.

The discovery of 2,4,6,8-tetramethylcyclotetrasiloxane can be traced back to the study of siloxane compounds in the mid-20th century, when researchers began exploring the unique properties of silicon-oxygen backbones. Siloxanes, including cyclic variants, were found to have excellent chemical stability, low surface tension, and thermal resistance, which sparked interest in their use in a variety of applications, including lubricants, coatings, and sealants. The specific synthesis of 2,4,6,8-tetramethylcyclotetrasiloxane involves the condensation of methylsilanols under controlled conditions, which leads to the formation of the cyclic structure.

One of the primary applications of 2,4,6,8-tetramethylcyclotetrasiloxane is in the formulation of personal care and cosmetic products. Its low viscosity and volatility allow it to be used as a carrier fluid in products such as hair sprays, deodorants, and skin care lotions. It imparts a smooth feel and non-greasy finish, improving the texture and sensory properties of the formulations. The compound is also used as an emollient, enhancing the spreadability and moisturizing effect of cosmetic products.

In the automotive and electronics industries, 2,4,6,8-tetramethylcyclotetrasiloxane is employed in various applications, including as a precursor in the synthesis of silicone-based lubricants and sealants. Its excellent thermal stability and resistance to oxidation make it particularly suitable for high-performance applications. It is often used in the manufacture of silicone-based lubricants that can withstand extreme temperatures and pressures, such as those found in automotive engines and electrical systems.

Another notable application of 2,4,6,8-tetramethylcyclotetrasiloxane is in the production of silicone rubber. The compound serves as a key intermediate in the synthesis of higher molecular weight siloxane polymers, which are then cross-linked to form flexible, durable silicone rubber. This material is widely used in industries ranging from medical devices to construction, thanks to its elasticity, biocompatibility, and resistance to temperature and environmental degradation.

In conclusion, 2,4,6,8-tetramethylcyclotetrasiloxane is a versatile compound with a broad range of applications across industries such as cosmetics, automotive, electronics, and manufacturing. Its unique combination of physical properties makes it an invaluable component in various formulations and products, contributing to improvements in product performance and consumer experience.

References

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