992-94-9Relevant academic research and scientific papers
Primary Processes in the Low-pressure Pyrolysis of Methylsilane
Davidson, Iain M. T.,Ring, Morey A.
, p. 1520 - 1525 (1980)
The low-pressure pyrolysis of methylsilane in the unimolecular fall-off region proceeds mainly by formation of molecular hydrogen: MeSiH3 MeSiH+H2; however, unimolecular formation of methane also occurs: MeSiH3 SiH2+CH4.Arrhenius parameters for both processes are estimated and some thermochemical deductions made.
Experimental and Theoretical Study of the Spin-Spin Coupling Tensors in Methylsilane
Kaski, Jaakko,Lantto, Perttu,Rantala, Tapio T.,Schroderus, Jyrki,Vaara, Juha,Jokisaari, Jukka
, p. 9669 - 9677 (1999)
The experimental and theoretical 13C-29Si spin-spin coupling tensors, 1JCSi, are reported for methylsilane, 13CH329SiH3. The experiments are performed by applying the liquid crystal NMR (LC NMR) method. The data obtained by dissolving CH3SiH3 in nematic phases of two LC's is analyzed by taking into account harmonic and anharmonic vibrations, internal rotation, and solvent-induced anisotropic deformation of the molecule. The necessary parameters describing the relaxation of the molecular geometry during the internal rotation, as well as the harmonic force field, are produced theoretically with semiempirical (AM1 and PM3) and ab initio (MP2) calculations. A quantum mechanical approach has been taken to treat the effects arising from internal rotation. All the J tensors are determined theoretically by ab initio MCSCF linear response calculations. The theoretical and experimental J coupling anisotropies, Δ1JCSi = -59.3 Hz and -89 ± 10 Hz, respectively, are in fair mutual agreement. These results indicate that the indirect contribution has to be taken into account when experimental 1DCSiexp couplings are to be applied to the determination of molecular geometry and orientation. The theoretically determined J tensors are found to be qualitatively similar to what was found in our previous calculations for ethane, which suggests that the indirect contributions can be partially corrected for by transferring the corresponding J tensors from a model molecule to another.
Communication: The insertion of silylene in C-H bonds; Rate constant limits and the energy barrier
Becerra, Rosa,Walsh, Robin
, p. 393 - 395 (1999)
The technique of laser flash photolysis has been used to set limits on the rate constants for the bimolecular reactions of SiH2 with methane (CH4) and tetramethylsilane (SiMe4) at both ambient and elevated temperatures (ca 600 K). These limits show that the energy barriers to insertion reactions of SiH2 in the C-H bonds of CH4 are at least 45(±6) kJ mol-1 and in the C-H and/or Si-C bonds of SiMe4 are at least 23(±6) kJ mol-1. The best thermochemical estimate of the activation energy for SiH2+CH4 is 59(±12) kJ mol-1. Reasons for the greatly diminished reactivity of SiH2 with C-H as compared with Si-H bonds are discussed.
PROCESS FOR THE STEPWISE SYNTHESIS OF SILAHYDROCARBONS
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Page/Page column 61; 62, (2021/12/08)
The invention relates to a process for the stepwise synthesis of silahydrocarbons bearing up to four different organyl substituents at the silicon atom, wherein the process includes at least one step a) of producing a bifunctional hydridochlorosilane by a redistribution reaction, selective chlorination of hydridosilanes with an ether/HCI reagent, or by selective chlorination of hydridosilanes with SiCI4, at least one step b) of submitting a bifunctional hydridochloromonosilane to a hydrosilylation reaction, at least one step c) of hydrogenation of a chloromonosilane, and a step d) in which a silahydrocarbon compound is obtained in a hydrosilylation reaction.
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.
Nucleophile induced ligand rearrangement reactions of alkoxy- and arylsilanes
Docherty, Jamie H.,Dominey, Andrew P.,Thomas, Stephen P.
, p. 3330 - 3335 (2019/05/10)
The ligand-redistribution reactions of aryl- and alkoxy-hydrosilanes can potentially cause the formation of gaseous hydrosilanes, which are flammable and pyrophoric. The ability of generic nucleophiles to initiate the ligand-redistribution reaction of commonly used hydrosilane reagents was investigated, alongside methods to hinder and halt the formation of hazardous hydrosilanes. Our results show that the ligand-redistribution reaction can be completely inhibited by common electrophiles and first-row transition metal pre-catalysts.
PROCESS FOR THE PRODUCTION OF ORGANOHYDRIDOCHLOROSILANES
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Page/Page column 35; 36, (2019/04/16)
The invention relates to a process for the manufacture of organomonosilanes bearing both hydrogen and chlorine substituents at the silicon atom by subjecting a silane substrate comprising one or more silanes selected from organomonosilanes, organodisilanes and organocarbodisilanes, with the proviso that at least one of these silanes has at least one chlorine substituent at the silicon atom, to a redistribution reaction in the presence of a phosphane or amine acting as a redistribution catalyst.
INTEGRATED PROCESS FOR THE MANUFACTURE OF METHYLCHLOROHYDRIDOMONOSILANES
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Page/Page column 41, (2019/04/16)
The present invention relates to an integrated process for the manufacture of methylchlorohydridomonosilanes in particular, from products of the Müller-Rochow Direct Process.
PROCESS FOR THE PRODUCTION OF ORGANOHYDRIDOCHLOROSILANES
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Page/Page column 28; 29; 30; 32; 37, (2019/04/16)
The invention relates to a process for the manufacture of organomonosilanes, in particular, bearing both hydrogen and chlorine substituents at the silicon atom by subjecting a silane substrate comprising one or more organomonosilanes, with the proviso that at least one of these silanes has at least one chlorine substituent at the silicon atom, to the reaction with one or more metal hydrides selected from the group of an alkali metal hydride and an alkaline earth metal hydride in the presence of one or more compounds (C) acting as a redistribution catalyst.
Making Use of the Direct Process Residue: Synthesis of Bifunctional Monosilanes
Sturm, Alexander G.,Santowski, Tobias,Schweizer, Julia I.,Meyer, Lioba,Lewis, Kenrick M.,Felder, Thorsten,Auner, Norbert,Holthausen, Max C.
supporting information, p. 8499 - 8502 (2019/06/13)
The industrial production of monosilanes MenSiCl4?n (n=1–3) through the Müller–Rochow Direct Process generates disilanes MenSi2Cl6?n (n=2–6) as unwanted byproducts (“Direct Process Residue”, DPR) by the thousands of tons annually, large quantities of which are usually disposed of by incineration. Herein we report a surprisingly facile and highly effective protocol for conversion of the DPR: hydrogenation with complex metal hydrides followed by Si?Si bond cleavage with HCl/ether solutions gives (mostly bifunctional) monosilanes in excellent yields. Competing side reactions are efficiently suppressed by the appropriate choice of reaction conditions.
