870-26-8Relevant academic research and scientific papers
Disilane Cleavage with Selected Alkali and Alkaline Earth Metal Salts
Santowski, Tobias,Sturm, Alexander G.,Lewis, Kenrick M.,Felder, Thorsten,Holthausen, Max C.,Auner, Norbert
supporting information, p. 13202 - 13207 (2019/10/22)
The industry-scale production of methylchloromonosilanes in the Müller–Rochow Direct Process is accompanied by the formation of a residue, the direct process residue (DPR), comprised of disilanes MenSi2Cl6-n (n=1–6). Great research efforts have been devoted to the recycling of these disilanes into monosilanes to allow reintroduction into the siloxane production chain. In this work, disilane cleavage by using alkali and alkaline earth metal salts is reported. The reaction with metal hydrides, in particular lithium hydride (LiH), leads to efficient reduction of chlorine containing disilanes but also induces disproportionation into mono- and oligosilanes. Alkali and alkaline earth chlorides, formed in the course of the reduction, specifically induce disproportionation of highly chlorinated disilanes, whereas highly methylated disilanes (n>3) remain unreacted. Nearly quantitative DPR conversion into monosilanes was achieved by using concentrated HCl/ether solutions in the presence of lithium chloride.
CLEAVAGE OF METHYLDISILANES, CARBODISILANES AND METHYLOLIGOSILANES WITH ALKALI-AND ALKALINE EARTH METAL SALTS
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Page/Page column 53; 54, (2019/04/16)
The invention relates to a process for the manufacture of methylmonosilanes comprising the step of subjecting one or more methyldisilanes, one or more methyloligosilanes, one or more carbodisilanes, or mixtures thereof to cleavage conditions resulting in the cleavage of silicon- silicon bonds or silicon-carbon bonds in carbodisilanes, and optionally a step of separating the resulting methylmonosilanes.
Reaction of Hydrogen Peroxide with Organosilanes under Chemical Vapour Deposition Conditions
Moore, Darren L.,Taylor, Mark P.,Timms, Peter L.
, p. 2673 - 2678 (2007/10/03)
When a stream of vapour at low pressure which contained a mixture of H2O2 with an organosilane, RSiH3 (R = alkyl or alkenyl), impinged on a silicon wafer, deposition of oxide films of nominal composition RxSiO(2-0.5x), where x 3 or higher alkenyl groups. or higher alkenylgroups. Possible mechanism for the Si-C bond cleavage reaction are discussed, with energetic rearrangement of radical intermediates of type Si(H)(R)(OOH)' being favoured.
Kinetics and Mechanism of the Reactions of O(3P) with SiH4, CH3SiH3, (CH3)2SiH2, and (CH3)3SiH
Horie, O.,Taege, R.,Reimann, B.,Arthur, N. L.,Potzinger, P.
, p. 4393 - 4400 (2007/10/02)
The reactions of O(3P) atoms with the silanes Me4-nSiHn (n = 1-4) have been investigated at room temperature in a discharge flow system with mass spectrometric detection and also in stationary photolysis experiments.Analysis of the end products provided conclusive evidence that the only primary process occuring in each case was the abstraction of hydrogen from the Si-H bond by the O atom leading to the formation of the OH and silyl radicals.The values of the rate constants obtained are k/10-13 cm3 s-1): k(O + SiH4) = 3.5, k(O + SiD4) = 1.4, k(O + MeSiH3) = 8.9; k(O + Me2SiH2) = 18.0, k(O + Me3SiH) = 30.6, and k(O + Me3SiD) = 16.0.The marked increase in rate constant with methylation is unexpected in view of the known similarity of the Si-H bond dissociation energy in SiH4 and the methylsilanes.A possible explanation is offered in terms of a reaction model involving partial charge transfer from Si to the attacking O, followed by proton transfer.
Mechanism of the Gas-Phase Thermolysis of Monomethylsilane
Neudorfl, P. S.,Lown, E. M.,Safarik, I.,Jodhan, A.,Strausz, O. P.
, p. 5780 - 5789 (2007/10/02)
The thermolysis of monomethylsilane (MMS) has been studied as a function of pressure (33-400 Torr), temperature (340-440 deg C), and conversion.Under conditions of very low (tipically, 0.5percent) conversion and in a carefully seasoned vessel the major products are H2 and dimethyldisilane (DMDS).Dimethylsilane (DMS) comprises ca. 5percent of the major products.MMS-d3 generates D2 exclusively.In the presence of ca. 10percent C2H4 the yields of H2 and DMDS are considerably reduced and both products follow first-order kinetics in their formation.Also, the formation of DMS is completely suppressed, and the Arrhenius parameters for the molecular process CH3SiH3 -> CH3H + H2 (1a) when determined from the rate of H2 production and from (CH3H + CH3SiH3 -> DMDS) production are log k1a = (15.02 +/- 0.10) - (63270 +/- 310) / 2.3RT and (14.87 +/- 0.12) - (63150 +/- 350) / 2.3RT, respectively.The molecular rate constant for H2, however, includes a small contribution from radical processes that cannot be completely suppressed.When the latter expression for k1a is used, the rate data for H2 is the unscavenged reaction can be fitted to a mechanism incorporating a second primary step, a slow, surface-catalyzed reaction generating H. and CH3SiH2. radicals , which then set up a short chain: CH3SiH2. + CH3SiH3 -> DMDS + H H + CH3SiH3 -> H2 + CH3SiH2. .On the basis of kinetic analysis of the data it is concluded that the chain is terminated linearly by CH3SiH2. radicals at the surface , with log A(s-1) = 11.7 and Ea ca. 32.3 kcal mol-1.The derived rate expression for the surface-catalyzed radical initation step CH3SiH3 -> Ch3SiH2. + H (1b) is log k1b = 12.7 - 57900/2.3RT.From the measured kinetic data the following themochemical values were derived: D(CH3H-H) = 73.5 kcal mol-1 and ΔHf(CH3H) = 51.9 kcal mol-1.
