Silane, Chloro-

In many cases, these cyclic siloxanes have to be removed from the system by distillation or fractionation, in order to obtain pure products. On the other hand, cyclic siloxanes where n = 3 and n = 4 are the two most important monomers used in the commercial production of various siloxane polymers or oligomers via the so-called equilibration or redistribution reactions which will be discussed in detail in Sect. 2.4. Therefore, in modern silicone technology, aqueous hydrolysis of chloro-silanes is usually employed for the preparation of cyclic siloxane monomers 122> more than for the direct synthesis of the (Si—X) functional oligomers. Equilibration reactions are the method of choice for the synthesis of functionally terminated siloxane oligomers. 

As shown in Table XIV, the reactivity of (trichloromethyl)silanes varied depending upon the substituent on silicon. The reactivity and yields of (trichloromethyl)-methyldichlorosilanes were slightly higher than those of (trichloroinethyl)tri-chlorosilanes in the aluminum chloride-catalyzed alkylation as similarly observed in the alkylations with (ai-chloroalkyl)silanes and (dichloroalkyl)silanes. The electron-donating methyl group on the silicon facilitates the alkylation more than the electron-withdrawing chlorine. The minor products, (diphenylmethyl)chloro-silanes, were presumably derived from the decomposition of (triphenylmethyl)-chlorosilanes. 

The O-alkyl O-silylphosphonates demonstrate the typical reactivity of phosphonates with a P-H bond. In silylation reactions with chloro silanes in presence of basis O-alkyl 0,0-disilylphosphonates can be synthesized. 

Aluminum phosphide Amyl trichlorosilane Benzoyl chloride Boron tribromide Boron trifluoride Boron trifluoride etherate Bromine pentafluoride Bromine trifluoride n-Butyl isocyanate Butyllithium Butyric anhydride Calcium Calcium carbide Chlorine trifluoride Chloro silanes Chlorosulfonic acid Chromium oxychloride Cyanamide Decaborane Diborane... 

There are two gereral routes to mikto-arm star polymers. The first method makes use of the stepwise addition of living polymers to multifunctional chloro-silane compounds [59-62], The Athens group uses the sequential addition of living polymers to multifunctional chlorosilane compounds under tight stoichiometric control [63, 64],... 

The first cyclopnict(V)azane, reported by Roesky and coworkers in 1983, was the arsenic compound 33, obtained by oxidative addition of CI2 and concomitant trimethyl(chloro)-silane elimination from a bis(trimethylsilyl)amidoAs(III) precursor. Equation (10.11). Each As atom in crystalline 33 is in a trigonal bipyramidal environment (Cl and axial) there is a rhomboidal (AsN)2 core, with the As—longer than the As-Neq bonds [a feature which is replicated in the (Sb N)2 compounds 34, 35, and 36, but differs from the (M N)2 compounds of Section 10.3.1]. Thermolysis of 33 yielded the crystalline compounds [As(CF3)2(p-N)] ,. (v = 3 or 4). ... 

The hydrolytic cleavage of the Si—N bond of aminosilanes does not proceed so fast as compared to the Si—0 and Si—Cl bond in similar alkoxysilanes and chloro-silanes, respectively. However, the hydrolysis can be accelerated by acidic catalysts. 

Vinyl(fluorodimethyl)silanes, RCH = CHSiF(CH3)2 (1). The reagents are prepared by reaction of the corresponding vinyl(chloro)silanes with copper fluoride. 

Trimethy I chloro-silane, (CH3)3SiCl Methyl dichloro-silane, CH3HSiCl2... 

Aryl(chloro) silanes, upon pretreatment with KF, smoothly undergo the palladium-catalyzed coupling with aryl bromides and iodides to give various biaryls. For this procedure, Pd(OAc)2 (0.5 mol%)/P(o-tol)3 (0.5 mol%) is convenient (Eq. 20). 

Decomposition of complex metal organic molecules are t3 ically endothermic reactions performed in furnace reactors. An example of a furnace decomposition is the thermal decomposition of dimethyl— chloro-silane to give silicon caihide [6] ... 

In recent years Furstner [15, 16] described the very rapidly and completely conversion of chloro-silanes into disilanes by the help of potassium-graphite (CgK). These coupling reactions were characterized by low temperatures (0-25 C), short reaction times (5-60 min), and high yields (> 90 %). So we tried to reduce our silyltriflate derivatives with potassium-graphite and we succeeded in preparing... 

Three classes of hybrid HPA are known to be stable to hydrolysis 1. Organometallic derivatives of the type RM (M = Si, Ge, Sn, Pb and R = alkyl or aryl). 2. Cyclopentadienyl-titaninm derivatives. 3. Zirconium alkoxide or phosphate derivatives, all of which are illustrated in Figure 2. We have tested phenyl model compounds of all of these for stability by boiling them in 6M HCl or H2O2 solution. This study showed that only PhP-O-HPA moieties are stable under conditions likely to be encountered in a fuel cell. Never the less we continue to study model compounds of the type RSi-O-HPA due to the large diversity of available ethoxy- and chloro- silanes. 

Silica gel-based materials for RP chromatography with nonpolar (most often Cg or Cjg alkyls) or moderately polar stationary phases covalently bonded via Si-O-Si-C bonds are prepared by chemical modification of the silanol (Si-OH) groups on the silica gel surface by chloro-silane or alkoxy-silane reagents, and are relatively stable to hydrolysis. The retention in RP increases with increasing surface coverage and length of the bonded alkyl chains, so that Cjg phases show greater retention than Cg-bonded phases. 

Intensive studies of the products of hydrolysis of substituted chloro-silanes and esters have led to an important new branch of chemistry. Many organo-silicon compounds were prepared by Kipping and his school in the early years of this century and it was observed that glue-like products often resulted from the hydrolysis of these compounds, as well as intractable solids of the kinds already mentioned. No study was made of these polymeric products which are now the basis of silicone chemistry. 

By analogy with carbon we might expect mono-, di-, and tri-chloro silanes to hydrolyse to the silicon analogues of alcohols, R3Si. OH, ketones R2Si=0 (by loss... 

Alkenyl(chloromethyl)siIanes undergo aluminum trichloride catalyzed rearrangement to form the corresponding allyl- and/or cyclopropyl(chloro)silanes 5 and/or 6, depending on the structure of the alkenyl group. ... 

A number of cyclopropyl silyl ethers have been prepared by treating cyclopropanols with chloro-silanes. Most frequently the alcohol is reacted with chlorotrimethylsilane in the presence of a weak base such as triethylamine, or pyridine, but reactions without base present have also been performed. The yields are often good thus, l-(l-ethylidenehexyl)cyclopropanol reacted with chlorotrimethylsilane in diethyl ether and dimethyl sulfoxide containing triethylamine to give l-(l-ethylidenehexyl)-l-trimethylsiloxycyclopropane (1) in excellent yield. ... 

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