Description

Octamethylcyclotetrasiloxane (CAS NO 556-67-2) is a key organosilicon compound and a fundamental building block in silicone chemistry. Its primary value lies in its role as a versatile intermediate for the synthesis of silicone polymers, oils, and elastomers. This product is essential for manufacturers in the personal care, pharmaceutical, and industrial sectors seeking reliable and high-purity siloxane feedstocks.

Application

• Silicone Polymer Intermediate: Serves as a crucial monomer (D4) for the production of polydimethylsiloxane (PDMS) fluids, resins, and rubbers.
• Personal Care & Cosmetics: Used in the formulation of hair conditioners, skin care products, and antiperspirants for its emollient and volatile carrier properties.
• Pharmaceutical & Medical: Acts as an excipient in topical formulations and as a precursor for medical-grade silicone materials.
• Industrial Lubricants & Release Agents: A base fluid for high-performance silicone lubricants and mold release agents.
• Textile & Fiber Treatment: Imparts water repellency and softness to fabrics and fibers.
• Electronics & Electrical: Used in dielectric fluids, heat transfer media, and as a protective coating precursor.

Basic Information

Product Name	Octamethylcyclotetrasiloxane
CAS No.	556-67-2
Molecular Formula	C8H24O4Si4
Molecular Weight	296.62 g/mol
Synonyms	D4; Cyclotetrasiloxane, octamethyl-; Octamethyltetracyclosiloxane; Tetramer; Octamethylcyclotetrasiloxane, D4; Cyclic dimethylsiloxane tetramer; 2,2,4,4,6,6,8,8-Octamethyl-1,3,5,7,2,4,6,8-tetraoxatetrasilocane; Decamethylcyclopentasiloxane (D5) is a related compound, not a synonym.
EINECS	209-136-7

Quality Control

Our Octamethylcyclotetrasiloxane is produced under strict quality management systems to ensure batch-to-batch consistency and high purity. Quality is verified through comprehensive analytical testing including gas chromatography (GC). A Certificate of Analysis (COA) detailing purity, identity, and specific parameters is provided with each shipment to meet the stringent requirements of our B2B partners.

Storage

Preserve in a tightly closed container, protected from light. Store in a cool, well-ventilated area away from heat sources and open flame. Due to its highly volatile nature, ensure containers are kept tightly sealed when not in use to prevent evaporation and maintain product integrity. Recommended storage temperature is 15-25°C.

Specification

Item	Specification
Appearance	Colorless clear liquid
Identification (IR)	Conforms
Assay (GC)	≥ 99.0%
Refractive Index (n20D)	1.396 - 1.398
Density (20°C)	0.955 - 0.958 g/cm³
Water Content	≤ 0.05%

Note: Specifications can be tailored. Please contact us for the detailed technical data sheet of a specific grade.