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Cyclotetrasiloxane

Octaphenyl cyclotetrasiloxane [546-56-5] M 793.2, m 201-202°, 203-204°, b 330-340°/lmm. Recryst from AcOH, EtOAc, or It forms two stable polymorphs and both... [Pg.446]

The a,oo-difunctional PDMS is obtained by cationic polymerization of octamethyl-cyclotetrasiloxane (D4) in the presence of a known amount of tetramethyldisiloxane, acting as a functional transfer agent. Hydrosilylation reaction is carried out in toluene solution at 90 °C with a platinum catalyst. [Pg.167]

Silica is also deposited by the decomposition of diacetoxy-ditertiarybutoxy silane (DADBS) at 450-550°C and low pressure (< 1 Torr) and by the decomposition of octamethyl-cyclotetrasiloxane in ozone at 400°C at low pressure.P ]P 1... [Pg.304]

The crystal structures of both the cis and the trans isomers of 2,8-dihydroxy-2,4,4,6,6,8,10,10,12,12-decamethylcyclohexasiloxane have been determined. In this case (unlike the cyclotetrasiloxane in Fig. 26), the cis isomer does contain an intramolecular hydrogen bond, and intermolecular hydrogen bonds link the molecules into cyclic pairs 57. The trans isomer cannot form intramolecular hydrogen bonds, but forms cyclic tetramers which are further hydrogen-bonded to form infinite sheets 58 (280). [Pg.222]

The cyclotetrasiloxane l,l,5,5-tetraphenyl-3,3,7,7-tetrahydroxycy-clotetrasiloxane forms a stable complex with two pyridine molecules trans to each other across the siloxane ring (316). The adduct may be prepared by the addition of an excess of pyridine to the free silanol the isomeric silanol [Ph(OH)SiO]4 does not form an adduct with pyridine (317). As well as hydrogen-bonding to the pyridine molecules, each of the two crystallographically independent molecules in the unit cell hydrogen-bonds to others of the same type to form two independent infinite chains (Fig. 24). Branching to form sheets by joining the chains, as in [But(0H)2Si]20, is partially blocked by the interactions with the... [Pg.242]

Figure 12.14 Pyrogram of the silicone coating from Mello s Tavolo erba. Peak assignments I, hexamethyi cyclotrisiloxane 2, octamethyl cyclotetrasiloxane 3, decamethyl cyiclopenta siloxane 4, dodecamethyl cyclohexasiloxane 5, tetradecamethyl cyclooctasiloxane... Figure 12.14 Pyrogram of the silicone coating from Mello s Tavolo erba. Peak assignments I, hexamethyi cyclotrisiloxane 2, octamethyl cyclotetrasiloxane 3, decamethyl cyiclopenta siloxane 4, dodecamethyl cyclohexasiloxane 5, tetradecamethyl cyclooctasiloxane...
Scheme 3. Synthesis of 2,6-m-diphenyl-hexamethyl-cyclotetrasiloxane and its trows-isomer... Scheme 3. Synthesis of 2,6-m-diphenyl-hexamethyl-cyclotetrasiloxane and its trows-isomer...
C/s-diphenyl-hexamethyl-cyclotetrasiloxane and its trans-isomer were also found to increase the brain dopamine content of animals57. A dose of 1—100 mg/kg 37 or 38 given daily over a period of about 7 days (orally or intravenously) is effective, depending on the species, the specific mode of administration, the carrier used, and the amount of increase that is desired. [Pg.22]

Biochemical effects of the non-steroidal oestrogen 2,6-cis-diphenyl-hexamethyl-cyclotetrasiloxane (Cisobitan ) were also investigated in mans8. Pharmacokinetic and clinical studies have been performed at Radiumhemmet, Stockholm, in patients with poorly differentiated prostatic carcinoma. The pharmaceutical preparation was made as a soy bean oil solution in soft capsules containing 100 mg Cisobitan per capsule. [Pg.22]

When (Me2SiO)3 (D3) was present, the diarylsilanone (83) was intercepted as the cyclotetrasiloxane (equation 130) this is a known reaction for silanone capture. [Pg.2552]


See other pages where Cyclotetrasiloxane is mentioned: [Pg.273]    [Pg.273]    [Pg.256]    [Pg.446]    [Pg.482]    [Pg.33]    [Pg.98]    [Pg.9]    [Pg.9]    [Pg.87]    [Pg.24]    [Pg.319]    [Pg.498]    [Pg.655]    [Pg.655]    [Pg.657]    [Pg.214]    [Pg.216]    [Pg.225]    [Pg.171]    [Pg.407]    [Pg.439]    [Pg.407]    [Pg.407]    [Pg.439]    [Pg.273]    [Pg.273]    [Pg.21]    [Pg.21]    [Pg.22]    [Pg.447]    [Pg.364]    [Pg.89]    [Pg.89]    [Pg.89]    [Pg.89]    [Pg.89]    [Pg.89]    [Pg.89]   
See also in sourсe #XX -- [ Pg.436 ]




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Asymmetric cyclotri-and cyclotetrasiloxanes

Asymmetric cyclotri-and cyclotetrasiloxanes preparation

Cyclotetrasiloxane equation

Cyclotetrasiloxanes

Cyclotetrasiloxanes

Cyclotetrasiloxanes, anionic polymerization

Octamethyl-cyclotetrasiloxane

Octaphenyl cyclotetrasiloxane

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