DODECAMETHYLCYCLOHEXASILOXANE

540-97-6

Cyclohexasiloxane, dodecamethyl-

Cyclomethicone 6

2,2,4,4,6,6,8,8,10,10,12,12-dodecamethyl-1,3,5,7,9,11-hexaoxa-2,4,6,8,10,12-hexasilacyclododecane

XHK3U310BA

2,2,4,4,6,6,8,8,10,10,12,12-Dodecamethylcyclohexasiloxane

EINECS 208-762-8

UNII-XHK3U310BA

HSDB 7723

EC 208-762-8

dodecamethyl cyclohexasiloxane

SCHEMBL93785

XIAMETER PMX-0246

CYCLOHEXASILOXANE [INCI]

DTXSID6027183

IUMSDRXLFWAGNT-UHFFFAOYSA-

CHEBI:191103

CYCLOMETHICONE 6 [USP-RS]

MFCD00144215

CYCLOHEXASILOXANE, DODECAMETHYL

AKOS015839990

FS-5671

DODECAMETHYLCYCLOHEXASILOXANE [MI]

DODECAMETHYLCYCLOHEXASILOXANE [HSDB]

DB-008587

D2040

DODECAMETHYLCYCLOHEXASILOXANE [WHO-DD]

NS00042693

S08515

T71035

Dodecamethylcyclohexasiloxane, analytical standard

A914553

Q27293843

2,2,4,4,6,6,8,8,10,10,12,12-Dodecamethylcyclohexasiloxane #

Cyclohexasiloxane, 2,2,4,4,6,6,8,8,10,10,12,12-dodecamethyl-

2,2,4,4,6,6,8,8,10,10,12,12-Dodecamethylcyclohexasiloxane, 95%

2,2,4,4,6,6,8,8,10,10,12,12-Dodecamethylcyclohexasiloxane, AldrichCPR

Cyclomethicone 6, United States Pharmacopeia (USP) Reference Standard

2,2,4,4,6,6,8,8,10,10,12,12-dodecamethyl-1,3,5,7,9,11-hexaoxa-2,4,6,8,10,12-hexa

D-6

InChI=1/C12H36O6Si6/c1-19(2)13-20(3,4)15-22(7,8)17-24(11,12)18-23(9,10)16-21(5,6)14-19/h1-12H3

The Henry's Law constant for dodecamethylcyclohexasiloxane is 25.0 atm-cu m/mole(1). This Henry's Law constant indicates that dodecamethylcyclohexasiloxane is expected to volatilize rapidly from water surfaces(2). Based on this Henry's Law constant, the volatilization half-life from a model river (1 m deep, flowing 1 m/sec, wind velocity of 3 m/sec)(2) is estimated as 6.2 hours(SRC). The volatilization half-life from a model lake (1 m deep, flowing 0.05 m/sec, wind velocity of 0.5 m/sec)(2) is estimated as 8.4 days(SRC). However, volatilization from water surfaces is expected to be attenuated by adsorption to suspended solids and sediment in the water column. The estimated volatilization half-life from a model pond is >1 year if adsorption is considered(3). The Henry's Law constant for dodecamethylcyclohexasiloxane indicates that volatilization from moist soil surfaces is expected(SRC). Dodecamethylcyclohexasiloxane is a volatile methylsiloxane that favors partitioning into the atmosphere(4); therefore, dodecamethylcyclohexasiloxane is expected to volatilize from dry soil surfaces(SRC) even with a vapor pressure of 0.0169 mm Hg(5). Evaporation of dodecamethylcyclohexasiloxane was measured in soil studies and found to occur with rates varying with moisture content, soil type and relative humidity(6). Volatilization from soil may be the major loss process under certain moist conditions(7).

Using a structure estimation method based on molecular connectivity indices(1), the Koc of dodecamethylcyclohexasiloxane can be estimated to be 870,000(SRC). According to a classification scheme(2), this estimated Koc value suggests that dodecamethylcyclohexasiloxane is expected to be immobile in soil.