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Description and features

SilQon OPCTS ( Octaphenylcyclotetrasiloxane ) is a white solid  which has C48H40O4Si4 as chemical formula. It can be used for synthesizing pharmaceutical intermediates and organic silicone intermediates, especially for high temperature resistant phenyl silicone oil and other polymers.

Octaphenylcyclotetrasiloxane  is also known as phenyl D4.


United States: Provided SilQon OPCTS is on stock in our local warehouse our lead time is about one week if delivered in 100 Kg drums.

Canada, South America, South Africa and other markets can also be served, please contact our sales department for more details.
➔ Not available in EU countries.

➔ Limited available in the Europe Union as this product has not been REACH registered (yet).

Product Identification

CAS number 546-56-5
EC number 208-904-9
HS code 2931 90 00
EC name Octaphenylcyclotetrasiloxane
IUPAC name Octaphenyl-1,3,5,7,2,4,6,8-tetraoxatetrasilocane


AppearanceWhite solid
Assay≥ 98.00 %


Octaphenylcyclotetrasiloxane is a siloxane that is used as a monomer in the production of phenyl silicone rubber. Besides it finds its application in the pharmaceutical industry for the syntheses of intermediates.


Available packaging: 100 KG drums.
Special packaging is available on request.


Store Octaphenylcyclotetrasiloxane in a cool, dry and well-ventilated area and in line with legal requirements.


A Material Safety Data Sheets (MSDS) is available for SilQon OPCTS and all other products supplied by Vesta Chemicals BV.

An MSDS describes the hazards of a product and explains how a product can be safely handled, used and stored. Besides it provides important regulatory and emergency response information for the purchased product.

Molecular and structural information

Molecular formula C48H40O4Si4
Molecular weight 793.17 g/mol
Structural formula

Physicochemical information

Boiling point 332 ºC
Bulk density 1.185 g/cm3 @ 25 ºC
Flash point 200 ºC
Log Pow 5.09
Solubility in water Insoluble in water
Vapor pressure 7.23e-11 mmHg

Octaphenylcyclotetrasiloxane | CAS: 546-56-5 | Disclaimer. This information is supplied solely for informational purposes and Vesta Chemicals bv makes no guarantees or warranties, either expressed or implied, with respect to the accuracy and use of this data. All product warranties and guarantees shall be governed by the Standard Terms of Sale. Nothing in this document is legal advice or is a substitute for competent legal advice.