Cyclic Silanols with Long Alkyl Chains

Well-defined cyclic silanol derivatives

“…Different from Yagihashi and Shimada group's case, Unno et al could isolate cis,trans-T 3 from hexyl-or octyltrichlorosilane (5 and 6, Table 2) only at short reaction times (1 h) by hydrolytic condensation. 54 With longer reaction times, the formed cyclotrisiloxanetriols disappeared and corresponding cyclotetrasiloxanetetraols were observed. Thus, 5 and 6 are kinetic products and cyclotetrasiloxanetetraols are thermodynamic products.…”

“…In the same year, Pizzotti et al reported a set of new sodium all-cis-arylcyclotetrasilanolates [4-RC 6 H 4 Si(ONa)O] 4 (39)(40)(41)(42), prepared from trialkoxyarylsilane (RSi(OR′) 3 , R = aryl). 77 The corresponding trimethylsiloxy derivatives [RSi(OSiMe 3 )O] 4 (53)(54)(55)(56) were synthesized by silylation and they can be used as scaffolds for anchoring second-order nonlinear optically active or fluorescent organic chromophores. Then they replaced the four bromo groups of 54 by four iodo substituents to afford compound 57.…”

A novel cyclic copolymer containing Si/P/N used as flame retardant and water repellent agent on cotton fabrics

“…The potassium cis-tetramethylcyclotetrasiloxanolate (KCTSi) was synthesized by the literature reports on other researchers. [28][29][30][31] KCTSi (16.60 g, 0.036 mol) was dissolved by 50 mL THF in a three-necked round-bottom flask equipped with a magnetic stirrer, a thermometer, and a circumference condenser, then added into chloromethyl dimethychlorosilane (20.82 g, 0.146 mol) drop by drop, and Et 3 N (2.50 g, 0.024 mol) used as catalyst. The mixture was stirred for 6 h at room temperature.…”

Preparation and Application Properties of Cyclic Polysiloxane Flame Retardant Containing Phosphorus and Nitrogen for Cotton Fabrics

“…17,18 However, studies on flame retardants based on cyclic polysiloxanes have rarely been reported. 19,20 Recently, Liu et al synthesized a novel polysiloxane quaternary ammonium salt (NCTSi) and used it as an antibacterial and hydrophobic agent for cotton fabrics, 19 inspiring the use of cyclic polysiloxanes as flame retardants. Cyclic polysiloxanes have four active sites, 20,21 which can be connected to more phosphorus-or nitrogencontaining groups, increasing the content of phosphorus and nitrogen in the flame retardant, so that the condensed-and gas-phase flame retardancy can be better imparted during combustion.…”

“…19,20 Recently, Liu et al synthesized a novel polysiloxane quaternary ammonium salt (NCTSi) and used it as an antibacterial and hydrophobic agent for cotton fabrics, 19 inspiring the use of cyclic polysiloxanes as flame retardants. Cyclic polysiloxanes have four active sites, 20,21 which can be connected to more phosphorus-or nitrogencontaining groups, increasing the content of phosphorus and nitrogen in the flame retardant, so that the condensed-and gas-phase flame retardancy can be better imparted during combustion. At the same time, the cyclic polysiloxane skeleton (as a flame retardant matrix) can form a "cake" molecular structure, which can be crosslinked with each other during burning, which is more conducive to forming a dense SiO 2 film to prevent transfer of heat and oxygen.…”