Dimethyldichlorosilane, reaction with

Dimethyl a-chloro-/3-phenyl-succinate, 222 Dimethyldichlorosilane, reaction with polyesters, 491... 

Thus we hope that these O-silylations-activations with the readily available HMDS (MesSiNHSiMes), TCS (MesSiCl), dimethyldichlorosilane (Me2SiCl2), hexa-methylcyclotrisilazane (HNSiMe2)s, OMCTS (HNSiMe2)4, tetra(alkoxy) silane (Si(OR)4) or sihcon tetrachloride (SiCL ), most of which can also effect the transient protection of any present hydroxyl group, and the subsequent or concomitant reaction with nucleophiles accompanied by formation of silylated water as HMDSO (MesSiOSiMes), (OSiMe2)n or Si02 will be applied more often in the fu-... 

Selectivity of contact mass. Since the most important products in the synthesis of organochlorosilanes are diorganodichlorosilanes, it is natural that the increase of their yield receives much attention. The selective formation of diorganodichlorosilanes when organic chlorine derivatives interact with contact mass is connected with the purity of the reactants, silicon above all. High yield of dimethyldichlorosilane in the direct synthesis of methylchlorosilanes largely depends on the presence of noticeable quantities of aluminum in contact mass. The yield of dimethyldichlorosilane in the presence of aluminum as a rule decreases due to the formation of trimethylchlorosilane in the reaction with pure (semiconductor) silicon in the presence of copper trimethylchlorosilane is virtually not formed. 

HSiCls and t-PrMgCl results in the formation of /-Pr2SiHCl, but the reaction with t-PrLi gives rise to t-Prs SiH. Preparation of t-butyldimethylchlorosilane from dimethyldichlorosilane requires the use of t-BuLi but an interesting accelerating effect of CN has been observed for the reaction of chlorosilanes with bulky r-BuMgCl. The reaction may proceed through a pentacoordinate intermediate (equation 6). ... 

Transition metals have already established a prominent role in synthetic silicon chemistry [1 - 5]. This is well illustrated by the Direct Process, which is a copper-mediated combination of elemental silicon and methyl chloride to produce methylchlorosilanes, and primarily dimethyldichlorosilane. This process is practiced on a large, worldwide scale, and is the basis for the silicones industry [6]. Other transition metal-catalyzed reactions that have proven to be synthetically usefiil include hydrosilation [7], silane alcdiolysis [8], and additions of Si-Si bonds to alkenes [9]. However, transition metal catalysis still holds considerable promise for enabling the production of new silicon-based compounds and materials. For example, transition metal-based catalysts may promote the direct conversion of elemental silicon to organosilanes via reactions with organic compounds such as ethers. In addition, they may play a strong role in the future... 

A similar reaction with 1,3,5-hexatriene and dimethyldichlorosilane yields the 1,1-dimethyl-2-vinyl-l-silacyclopent-3-ene when THE and CU2CI2 are employed [110],... 

SUiconides. The steroidal cis-diol, A5-3/3-acetoxy-16a,17a-dihydroxy-pregnene-20-one (1), is converted by reaction with dimethyldichlorosilane in pyridine into a cyclic silyldioxy compound (2). In analogy with acetonides, the name siliconide is suggested for such a derivative.1... 

Chloride is determined by mercurimetric titration to the sodium nitroprusside end-point. Carbonates, acetates and borates do not interfere in the titration but large amounts of ammonium salts do interfere. The method has been applied to methyltrichlorosilane, dimethyldichlorosilane, diethyldichlorosilane, phenylmethyldichlorosilane and phenyltrichlorosilane. Methods have been described76,77 based on reaction with amines for the determination of chlorine directly linked to silicon in alkyl aryl chlorosilanes. One method76 is based on the formation of aniline hydrochloride according to the equation ... 

Dimethyldichlorosilane reacts with the active sites of the solid support giving both the cyclic silyl ether, formed by the reaction of one molecule of DMCS with two silanol groups, and also the monochlorosilyl ether. Consequently, it is necessary to treat the solid support further with methanol in order to convert the chlorosilyl group into its methyl ether derivative. 

Prepd by hydrolyzing dimethyldichlorosilane or its esters followed by oxidation with air and a catalyst to the desired CHj/Si ratio Hyde, DeLong, ibid. I ]94 by hydrolysis of dimethyldichlorosilane mixed with methyltrich]oro. silane or silicon tetrachloride followed by cocondensation of the products Rochow, Gilliam, loc. elf, by partially methylating silicon tetrachloride to the desired CH3/Si ratio and hydrolyzing the reaction mixture U.S, pat. 2,258,218 (1941). 

Polysilane is usually synthesized from dichlorosilane (RiR2SiCl2) by dechlorination condensation reaction with sodium. Various types of alkyl or aryl groups can be added to (the changing monomers) main -Si-Si- chain. Polysi-lastyrene is a representative copolymer synthesized by this method of mixing the monomers [7] dimethyldichlorosilane and phenylmethyldichlorosilane [8]. 

The representative organosilicon compounds having an Si—N bond are silazanes. The silazanes are usually prepared by the reaction of chlorosilanes with ammonia. For example, trimethylchlorosilane reacts with ammonia to give hexamethyldisi-lazane. Dimethyldichlorosilane reacts with ammonia to give a mixture of cyclic hexamethylcyclotrisilazane and octamethylcyclotetrasilazane [31]. 

The purity of the product was determined by the checkers by GLC analysis using the following column and conditions 3-nm by 1.8-m column, 5% free fatty acid phase (FFAP) on acid-washed chromosorb W (60-80 mesh) treated with dimethyldichlorosilane, 90 C (1 min) then 90 to 200 C (15°C per rain). The chromatogram showed a major peak for methyl 2-methyl-l-cyclohexene-l-carboxylate preceded by two minor peaks for methyl 1-cyclohexene-l-carboxylate and l-acetyl-2-methylcyclohexene. The areas of the two impurity peaks were 5-6% and 0.5-2% that of the major peak. The purity of the product seems to depend upon careful temperature control during the reaction. The total amount of the two impurities was 14-21% in runs conducted at about -15 to -20°C or at temperatures below -23°C. 

Under the most favourable reaction conditions when methyl chloride is used the crude product from the reaction tube will be composed of about 73.5% dimethyldichlorosilane, 9% trichloromethysilane and 6% chlorotrimethylsilane together with small amounts of other silanes, silicon tetrachloride and high boiling residues. 

As already discussed in Section 2.2, crystalline dimethylsilanediol 53 can be prepared by hydrolysis from hexamethylcyclotrisilazane 51, from dimethoxydimethyl-silane [40], and from octamethylcyclotetrasilazane (OMCTS) 52. The most simple preparation of 53 is, however, controlled hydrolysis of dimethyldichlorosilane 48 in the presence of (NH4)2C03 or triethylamine [41]. Likewise, hydrolysis of hexam-ethylcyclotrisiloxane 54 and of octamethylcyclotetrasiloxane 55 eventually gives rise to dimethylsilanediol 53. In all these reactions the intermediacy of the very reactive dimethylsilanone 110 has been assumed, which can be generated by pyrolytic [42, 43] and chemical methods [44—46] and which cyclizes or polymerizes much more rapidly, e.g. in contact with traces of alkali from ordinary laboratory or even Pyrex glassware [40, 47] to 54, 55, and 56 than trimethylsilanol 4 polymerizes to hexamethyldisiloxane 7. Compound 111 is readily converted into dimethylsilanone 110 and MesSil 17 [46] (Scheme 3.6). 

Organosilanes, especially dimethyldichlorosilane (M2), are important chemicals used in the silicone industries. The direct reaction of silicon with an organic halide to produce the corresponding organosilanes as a gas-solid-solid catalytic reaction was first disclosed by Rochow [1]. In the reaction, a copper-containing precursor first reacts with silicon particles to form the catalytically active component, which is a copper-silicon alloy, the exact state of which is still under discussion. As the reaction proceeds. Si in the alloy is consumed, which is followed by the release of copper. This copper diffuses into the Si lattice to form new reaction centers until deactivation occurs. The main reaction of the direct process is ... 

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