Octaphenylcyclotetrasiloxane

CAS NO.：546-56-5
Empirical Formula: C48H40O4Si4
Molecular Weight: 793.18
MDL number: MFCD00003268
EINECS: 208-904-9
SAFETY DATA SHEET (SDS)
Update Date: 2026-05-28 03:31:06

What is Octaphenylcyclotetrasiloxane?

Chemical properties

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

Preparation

Octaphenylcyclotetrasiloxane is typically produced industrially by one of two processes: 1) the hydrolysis of diphenyldichlorosilane or 2) the hydrolysis of diphenyldialkoxysilanes.
Process the production of octaphenylcyclotetrasiloxane

Flammability and Explosibility

Not classified

Purification Methods

Recrystallise it from AcOH, EtOAc, *C6H6 or *C6H6/EtOH. It forms two stable isomorphs and both forms, as well as the mixture, melt at 200-201o. There is a metastable form which melts at 187-189o. [Burkhard et al. J Am Chem Soc 67 2174 1945, Hyde et al. J Am Chem Soc 69 488 1947, Beilstein 16 IV 1530.]

Properties of Octaphenylcyclotetrasiloxane

Melting point:	196-198 °C(lit.)
Boiling point:	334 °C
Density	1.185
vapor pressure	0Pa at 25℃
refractive index	1.62
Flash point:	200 °C
solubility	very faint turbidity in Toluene
form	solid
Specific Gravity	1.185
color	White to Almost white
Water Solubility	insoluble
Hydrolytic Sensitivity	1: no significant reaction with aqueous systems
BRN	2320758
CAS DataBase Reference	546-56-5(CAS DataBase Reference)
NIST Chemistry Reference	Octaphenylcyclotetrasiloxane(546-56-5)
EPA Substance Registry System	Cyclotetrasiloxane, octaphenyl- (546-56-5)

Safety information for Octaphenylcyclotetrasiloxane

Signal word	Warning
Pictogram(s)	Exclamation Mark Irritant GHS07
GHS Hazard Statements	H302:Acute toxicity,oral
Precautionary Statement Codes	P280:Wear protective gloves/protective clothing/eye protection/face protection. P305+P351+P338:IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continuerinsing.