HMDSO Hexamethyldisiloxane

AI3-51466 Belsil DM 0.65 Bis-trimethylsilyl oxide Bistrimethylsilyl ether CCRIS 1325 CH7310 Disiloxane, hexamethyl- EINECS 203-492-7 Fluka AG H7250 H7310 HMDSO Hexamethyldisiloxane HMS HSDB 5378 KF 96L NSC 43346 OS 10 Oxybis(trimethyl-silane) Silane, oxybis(trimethyl- SWS-F 221. Coupling agent. 

Another illustrative example of the application of FTIR spectroscopy to problems of interest in adhesion science is provided by the work of Taylor and Boerio on plasma polymerized silica-like films as primers for structural adhesive bonding [15]. Mostly these films have been deposited in a microwave reactor using hexamethyldisiloxane (HMDSO) as monomer and oxygen as the carrier gas. Transmission FTIR spectra of HMDSO monomer were characterized by strong... 

Polar functional groups such as alcohols or phenols 11 or trimethylsilanol 4 are transformed by monofunctional silylating reagents Me3SiX 12 into their hpophilic and often volatile trimethylsilyl ethers 13 whereas water is converted into persilyl-ated water (=Me3SiOSiMe3, hexamethyldisiloxane, HMDSO, 7, b.p. 100 °C). The persilylation of phenols and, in particular, catechol (or hydroquinone) systems (Scheme 2.1) protects them efficiently against air oxidation even at temperatures of up to 180 °C. (cf, e.g., the silylation-amination of purine nucleosides with dopamine hydrochloride in Section 4.2.4)... 

Trimethylsilyl iodide 17, which can be generated in situ by reaction of trimethyl-silyl chloride (TCS) 14 with Nal in acetonitrile [1], converts alcohols 11, in high yields at room temperature, into their iodides 773a, HI, and hexamethyldisiloxane (HMDSO) 7 [1-8, 12]. Likewise esters such as benzyl benzoate are cleaved by Me3SiCl 14/NaI in acetonitrile under reflux [Ij. Reactions of alcohols 11 with trimethylsilyl bromide 16 in chloroform or, for in situ synthesis of 16 from liBr and TCS 14 in acetonitrile and with HMDS 2 and pyridinium bromide perbromide, proceed only on heating in acetonitrile or chloroform to give the bromides 773 b in nearly quantitative yield [3, 8, 12] (Scheme 6.1). 

Reaction of pyridine N-oxide 860 with excess allyltrimethylsilane 82 affords, via 947, 2-propenylpyridine 948 in 53% yield as the only reaction product which can be isolated. Ehmination of trimethylsilanol 4 from 947 is apparently followed by fluoride-catalyzed isomerization of 2-allylpyridine into 2-propenylpyridine 948. 3-Methylpyridine-N-oxide 867 a is converted into 2-propenyl-3-methylpyridine in 69% yield. Likewise, fluoride-catalyzed addition of excess benzyltrimethylsilane 83 to 860 furnishes, via 949, 2-benzylpyridine 950 in 70% yield. The generated leaving group trimethylsilanol 4 reacts with excess allyltrimethylsilane 82 or benzyltrimethylsilane 83 in the presence of fluoride to give hexamethyldisiloxane (HMDSO) 7 and propylene or toluene, respectively [60] (Scheme 7.16). 

The N-bis-silylated o-phenylenediamine 1511 reacts with DMF at 120°C to give benzimidazole, in 97% yield, and dimethylamine and hexamethyldisiloxane 7, whereas reaction of benzaldehyde with 1511 gives only 29% 2-phenylbenzimida-zole 1513, because the intermediate benzimidazoline 1512 is only rather slowly dehydrogenated to 1513 [52]. Heating of N,N -bis(trimethylsilyl)ethylenediamine 1514 with DMF affords imidazoline 1515 and dimethylamine and HMDSO 7 ]52] (Scheme 9.32). The lactam 1516 cycHzes analogously with SiCU 57/triethylamine in 63% yield to give 1517 ]53]. 

The preparation of phosphaalkynes, which has been reviewed [1, 4], usually implies elimination of trimethylchlorosilane (TCS) 14 or of hexamethyldisiloxane (HMDSO) 7. Thus pyrolysis of the chloro compounds 1722 and 1723 at 750 or 630 °C, respectively, affords the trimethylsilylphosphaacetylene 1724 and TCS 14. 

In the most versatile preparation of phosphaalkynes, acid chlorides such as pivaloyl chloride [27] are reacted either with P(SiMe3)3 1692, with formation of TCS 14, or with (Me3Si)2PLi 1725 [26] to give the phosphides 1726 [28, 29], which eliminate hexamethyldisiloxane (HMDSO) 7 in the presence of catalytic amounts of NaOH [28] either in a solvent or more efficiently without a solvent at 120-200 °C [29, 30] to afford, via 1727, the corresponding phosphaalkynes 1728 and HMDSO 7 [1, 4] (Scheme 11.7). 

BU4NF-2-3H20 (1.89 g, 6 mmol) in 20 mb abs. THF is cooled to 0°C and hexa-methyldisilazane 2 (HMDS 4.3 g, 27 mmol) is added with stirring and exclusion of humidity. After stirring for 12 h at room temperature the volatile components, including the hexamethyldisiloxane (HMDSO) 7 (b.p. 100°C), are removed in vacuo. After 3 h the semi-crystalline, colorless residue is dissolved, under argon, in 10 mb abs. THF [14] (Scheme 13.29). 

The H-NMR spectra of FCC feeds were recorded on a Bruker DRX 400 MHz NMR spectrometer. The concentration of the samples of 5 wt% in CDCI3 was recommended by Molina, Navarro Uribe, and Murgich [2] to avoid concentration dependence of the chemical shift. A 30° pulse sequence was applied, with 4.089 s acquisition time, 2 s pulse delay [2], 8012.8 Hz spectral width, and 64 scans. Hexamethyldisiloxane (HMDSO) was used as a reference. NMR processing was realized using MestReNova software. The phase and baseline of the resulting spectra were manually adjusted and corrected. The spectra were integrated six times and average values were taken for the purpose of calculations. The spectra were divided... 

This article describes recent advances in the experimental determination of electron impact ionization cross sections for silane (SiH4) its radicals, SiH. (x = 1 to 3) and the Si-organic molecules tetramethylsilane (TMS), Si(CH3)4 tetraethoxysilane (TEOS), Si(0-CH2-CH3)4 and hexamethyldisiloxane (HMDSO), (CH3)3-Si-0-Si-(CH3)3, which is one of the simplest siloxane compounds. These are model substances, and the results obtained for these species may be used in efforts to predict the ionization properties of other, more complex Si-organic molecules. The ionization cross sections of the stable compounds were measured using a high-resolution double-focusing mass spectrometer. The cross-section data for the radicals were obtained in a fast-neutral-beam apparatus. 

Hexamethyldisiloxane (HMDSO) is one of the simplest siloxane compounds it has been successfully used in plasma-assisted thin-film deposition applications... 

Ways have been investigated to reduce or avoid leaching of plasticizers. Barreto et al. (2012) deposited a barrier coating onto PVC, resulting in a reduction of more than 80% of leaching of the plasticizer. The barrier was established by means of plasma-activated CVD used to polymerize octamethylcyclotetrasiloxane (OMCTS) and hexamethyldisiloxane (HMDSO). Covalent bonding of the plasticizer to PVC... 

The hybrid films for the pinhole-free electrical insulators were prepared using hexamethyldisiloxane (HMDSO) and silicon monoxide (SiO) [64]. The HMDSO hybrid films were prepared on the substrates by evaporating SiO during HMDSO plasma polymerisation in RF discharge. SiO was evaporated by heating in RF plasma consisting of HMDSO and oxygen at a pressure of 10 Torn... 

Figure 19.8 shows the pH-dependence of zeta potential in ImM NaCl for three plasma polymer surfaces having different functional characteristics. The respective surfaces of this figure are plasma-polymerized acrylic acid, hexamethyldisiloxane (HMDSO) and 1,2-diaminocyclohexane (DACH). It is evident from the figure that these surfaces have very different electrokinetic surface properties. This pH-dependence clearly... 

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