- Hydrosilylation reaction of ethylene with triethoxysilane catalyzed by ruthenium halides and promoted by cuprous halides
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The hydrosilylation reaction of ethylene with triethoxysilane catalyzed by ruthenium halides and promoted by cuprous halides, iodine or ferrous chloride tetrahydrates was conducted at temperatures ranging from 30 to 80 C under a mild pressure of ethylene gas. Ruthenium chloride trihydrates and cuprous chloride are proved to be the best catalyst and promoter for this reaction. With the addition of 6.8 × 10-5 mol ruthenium chloride trihydrates per mole of triethoxysilane together with over 3 times of cuprous chloride per mole of ruthenium chloride trihydrates, the reaction can conduct rapidly at temperatures ranging from 40 to 60 C under a pressure of ethylene gas lower than 0.35 MPa with over 96% yield of ethyltriethoxysilane within 6 h.
- Liu, Ling,Li, Xiaonian,Dong, Hong,Wu, Chuan
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Read Online
- Sustainable Catalytic Synthesis of Diethyl Carbonate
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New sustainable approaches should be developed to overcome equilibrium limitation of dialkyl carbonate synthesis from CO2 and alcohols. Using tetraethyl orthosilicate (TEOS) and CO2 with Zr catalysts, we report the first example of sustainable catalytic synthesis of diethyl carbonate (DEC). The disiloxane byproduct can be reverted to TEOS. Under the same conditions, DEC can be synthesized using a wide range of alkoxysilane substrates by investigating the effects of the number of ethoxy substituent in alkoxysilane substrates, alkyl chain, and unsaturated moiety on the fundamental property of this reaction. Mechanistic insights obtained by kinetic studies, labeling experiments, and spectroscopic investigations reveal that DEC is generated via nucleophilic ethoxylation of a CO2-inserted Zr catalyst and catalyst regeneration by TEOS. The unprecedented transformation offers a new approach toward a cleaner route for DEC synthesis using recyclable alkoxysilane.
- Putro, Wahyu S.,Ikeda, Akira,Shigeyasu, Shinji,Hamura, Satoshi,Matsumoto, Seiji,Lee, Vladimir Ya.,Choi, Jun-Chul,Fukaya, Norihisa
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p. 842 - 846
(2020/12/07)
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- CATALYST AND RELATED METHODS INVOLVING HYDROSILYLATION AND DEHYDROGENATIVE SILYLATION
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A catalyst having a specific structure and a method fop rearing the catalyst is disclosed. A composition is also disclosed, which comprises: (A) an unsaturated compound including at least one aliphatically unsaturated group per molecule, subject to at least one of the following two provisos: (1) the (A) unsaturated compound also includes at least one silicon-bonded hydrogen atom per molecule; and/or (2) the composition further comprises (B) a silicon hydride compound including at least one silicon-bonded hydrogen atom per molecule. The composition further comprises (C) the catalyst. A method of preparing a hydrosilylation reaction product and a dehydrogenative silylation reaction product are also disclosed.
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Paragraph 00152-00154; 00157; 00160; 00155
(2019/02/06)
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- Fe and Co Complexes of Rigidly Planar Phosphino-Quinoline-Pyridine Ligands for Catalytic Hydrosilylation and Dehydrogenative Silylation
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Co and Fe dihalide complexes of a new rigidly planar PNN ligand platform are prepared and examined as precatalysts for hydrosilylation of alkenes. Lithiation of Thummel's 8-bromo-2-(pyrid-2′-yl)quinoline followed by treatment with (i-Pr)2PCl and (C6F5)2PCl afforded the phosphine-quinoline-pyridine ligands, abbreviated RPQpy for R = i-Pr and C6F5, respectively. These ligands form 1:1 adducts with the dichlorides and dibromides of iron and cobalt. Crystallographic characterization of FeBr2(iPrPQpy), FeBr2(ArFPQpy), CoCl2(iPrPQpy), CoBr2(iPrPQpy), and CoCl2(ArFPQpy) confirmed that the M-P-C-C-N-C-C-N portion of these complexes is planar within 0.078 ? unlike previous generations of PNN complexes where deviations from planarity were ～0.35 ?. Bond distances as well as magnetism indicate that the Fe complexes are high spin and the cobalt complexes are high spin or participate in spin equilibria. Also investigated were the NNN analogues of the RPQpy ligands, wherein the phosphine group was replaced by the mesityl ketimine. The complexes FeBr2(MesNQpy) and CoCl2(MesNQpy) were characterized crystallographically. Reduction of MX2(RPQpy) complexes with NaBHEt3 generates catalysts active for anti-Markovnikov silylation of simple and complex 1-alkenes with a variety of hydrosilanes. Catalysts derived from MesNQpy exhibited low activity. Fe-RPQpy derived catalysts favor hydrosilylation, whereas Co-RPQpy based catalysts favor dehydrogenative silylation. Catalysts derived from CoX2(iPrPQpy) convert hydrosilanes and ethylene to vinylsilanes. Related experiments were conducted on propylene to give propenylsilanes.
- Basu, Debashis,Gilbert-Wilson, Ryan,Gray, Danielle L.,Rauchfuss, Thomas B.,Dash, Aswini K.
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p. 2760 - 2768
(2018/09/10)
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- MONONUCLEAR IRON COMPLEX AND ORGANIC SYNTHESIS REACTION USING SAME
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Provided is a mononuclear iron complex that comprises an iron-silicon bond that is represented by formula (1) and that exhibits excellent catalyst activity in each of a hydrosilylation reaction, a hydrogenation reaction, and reduction of a carbonyl compound. In formula (1), R 1 -R 6 either independently represent an alkyl group, an aryl group, an aralkyl group or the like that may be substituted with a hydrogen atom or X, or represent a crosslinking substituent in which at least one pair comprising one of R 1 -R 3 and one of R 4 -R 6 is combined. X represents a halogen atom, an organoxy group, or the like. L represents a two-electron ligand other than CO. When a plurality of L are present, the plurality of L may be the same as or different from each other. When two L are present, the two L may be bonded to each other. n and m independently represent an integer of 1 to 3 with the stipulation that n+m equals 3 or 4.
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Paragraph 0215-0217
(2016/12/01)
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- COSMETIC TREATMENT METHOD COMPRISING THE APPLICATION OF A COATING BASED ON AN AEROGEL COMPOSITION OF LOW BULK DENSITY
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The present invention relates to a cosmetic treatment method comprising the formation of a coating on keratin fibres characterized in that it comprises: 1) the preparation of an aerogel precursor composition comprising:—at least one organic solvent chosen from acetone, C1-C4 alcohols, C1-C6 alkanes, C1-C4 ethers, which may or may not be perfluorinated, and mixtures thereof and at least one precursor compound that contains:—at least one atom chosen from silicon, titanium, aluminium and zirconium,—at least one hydroxyl or alkoxy function directly attached to the atom chosen from silicon, titanium, aluminium and zirconium by an oxygen atom, and,—optionally an organic group directly attached to the atom chosen from silicon, titanium, aluminium and zirconium by a carbon atom, 2) the removal of the solvent or solvents resulting in the formation of an aerogel composition having a bulk density less than or equal to 0.35 g/cm3, 3) the application to the keratin fibres of the aerogel composition resulting from step 2) or of the aerogel precursor composition resulting from step 1). Advantageously, the molar ratio between the precursor compounds and the solvent is at most 1/20.
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Paragraph 0067
(2014/02/15)
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- Catalyst design for iron-promoted reductions: An iron disilyl-dicarbonyl complex bearing weakly coordinating η2-(H-Si) moieties
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Iron disilyl dicarbonyl complex 1, in which two H-Si moieties of the 1,2-bis(dimethylsilyl)benzene ligand were coordinated to the iron center in an η2-(H-Si) fashion, was synthesized by the reaction of (η4-C6H8)Fe(CO)3 with 2 equiv. of 1,2-bis(dimethylsilyl)benzene under photo-irradiation. Complex 1 demonstrated high catalytic activity toward the hydrogenation of alkenes, the hydrosilylation of alkenes and the reduction of carbonyl compounds.
- Sunada, Yusuke,Tsutsumi, Hironori,Shigeta, Keisuke,Yoshida, Ryota,Hashimoto, Toru,Nagashima, Hideo
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supporting information
p. 16687 - 16692
(2013/12/04)
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- Stereoselective synthesis of (E)- and (Z)-triethoxy(vinyl-d 2)silanes by hydrosilylation of acetylene-d 2
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The hydrosilylation of deuterated acetylene with triethoxysilane can be directed to the synthesis of either cis or trans triethoxy(vinyl-d 2)silanes by an appropriate choice of metal catalyst. In addition, we have demonstrated the viability of designing hydrosilylation-arylation sequential processes in which acetylene can be converted into styrenes or stilbenes using the same Pd catalyst for both reactions.
- Gordillo, Alvaro,Forigua, Johan,Lopez-Mardomingo, Carmen,De Jesus, Ernesto
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experimental part
p. 352 - 355
(2011/03/21)
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- Facile synthetic access to rhenium(II) complexes: Activation of carbonbromine bonds by single-electron transfer
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The five-coordinated Re1 hydride complexes [Re(Br)(H)(NO) (PR3)2] (R = Cy la, iPr lb) were reacted with benzylbromide, thereby affording the 17-electron mononuclear ReII hydride complexes [Re(Br)2(H)(NO)(PR3)2] (R = Cy 3a, iPr 3b), which were characterized by EPR, cyclic voltammetry, and magnetic susceptibility measurements. In the case of dibromomethane or bromoform, the reaction of 1 afforded ReII hydrides 3 in addition to Re1 carbene hydrides [Re(= CHR1)(Br)(H)(NO)(PR3)2,] (R 1 = H 4, Br 5; R = Cy a, iPr b) in which the hydride ligand is positioned cis to the carbene ligand. For comparison, the dihydrogen Re 1 dibromide complexes [Re(Br)2(NO)(PR3MIf- H2)] (R = Cy 2 a, iPr 2 b) were reacted with allyl- or benzylbromide, thereby affording the monophosphine ReII complex salts [R 3PCH2R'][Re(Br)4(NO)(PR3)] (R' = -CH=CH2 6, Ph 7). The reduction of ReII complexes has also been examined. Complex 3 a or 3 b can be reduced by zinc to afford la or lb in high yield. Under catalytic conditions, this reaction enables homocoupling of benzylbromide (turnover frequency (TOF): 3a 150, 3b 134 h-1) or allylbromide (TOF: 3a 150, 3b 562 h-1). The reaction of 6 a and 6 b with zinc in acetonitrile affords in good yields the monophosphine Re 1 complexes [Re(Br)2(NO)(MeCN)2(PR 3)] (R = Cy 8a, iPr 8b), which showed high catalytic activity toward highly selective dehydrogenative silylation of styrenes (maximum TOF of 61 h-1). Single-electron transfer (SET) mechanisms were proposed for all these transformations. The molecular structures of 3 a, 6 a, 6 b, 7 a, 7 b, and 8 a were established by single-crystal X-ray diffraction studies.
- Jiang, Yanfeng,Blacque, Olivier,Fox, Thomas,Freeh, Christian M.,Berke, Heinz
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scheme or table
p. 2240 - 2249
(2010/07/05)
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- Process for the direct synthesis of trialkoxysilane
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This invention discloses a process to improve reaction stability in the Direct Synthesis of trialkoxysilanes. The process is particularly effective in the Direct Synthesis of triethoxysilane and its higher alkyl cognates providing improved triethoxysilane yields.
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Page/Page column 17
(2008/06/13)
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- Hydrosilylation of ethylene
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Hydrosilylation of ethylene with trialkoxysilanes in the presence of Pt(0) complexes as catalysts affords ethyltrialkoxysilanes in almost quantitative yields. No impurities of vinyltrialkoxysilanes were detected. Experiments and ab initio calculations showed that the Pt(0) catalysts are considerably more active in ethylene hydrosilylation than Pt(II) catalysts. Pleiades Publishing, Inc., 2006.
- Chernyshev,Belyakova,Knyazev,Turkel'taub,Parshina,Serova,Storozhenko
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p. 225 - 228
(2008/02/08)
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- Continuous and batch organomagnesium synthesis of ethyl-substituted silanes from ethylchloride, tetraethoxysilane, and organotrichlorosilane for production of polyethylsiloxane liquids. 2. Continuous one-step synthesis of ethylethoxy- and ethylchlorosilanes
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Development of a continuous one-step manufacturing process for ethylethoxy- and ethylchlorosilanes is described. The methodology of synthesis of ethyl-substituted silanes has been improved. The important factors for the successful synthesis have been determined. Among them are (1) the replacement of some tetraethoxysilane 3 by ethyltrichlorosilane 10, (2) the optimum concentration of 3 and 10, (3) the excess of the granulated magnesium (the supply rate 50-110 g h-1), and, finally, (4) the columnar apparatus with the stirrer, resulting in high yields of di-and triethylsilanes, low duration of synthesis, and high selectivity of Grignard reagent. Continuous one-step synthesis has been assimilated into industry (up to a scale 7-40 kg h-1 of magnesium) for production of oligoethylsiloxanes with low (5-20%) and high content (up to 40%) of the terminal triethylsiloxy groups. The rules for R/D process of the Grignard synthesis are described.
- Klokov, Boris A.
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p. 234 - 240
(2013/09/07)
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- Method for making organooxysilanes
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A method for the preparation of organooxysilanes containing at least one silicon-carbon bond is provided which comprises reaction of at least one tetraorganooxysilane with at least one metal hydride.
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- Direct synthesis of alkyldialkoxysilanes by the reaction of silicon, alcohol and alkene using a high-pressure flow reactor
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In the reaction of silicon, methanol and ethylene, use of a high-pressure flow reactor operating at 240°C at 0.86 MPa of ethylene and 0.18 MPa of methanol gave a 33% selectivity for ethyldimethoxysilane, which was much higher than that using an atmospheric-pressure flow reactor (8%) or using an autoclave (4%). The selectivity increased proportionally with the ethylene pressure below 0.5 MPa. This indicates that the addition of ethylene or methanol to a surface silylene intermediate determines the selectivity and that the ethylene addition is a first-order reaction. Above 0.5 MPa the slope of the selectivity change was smaller. By feeding propylene instead of ethylene, n- and iso-propyldimethoxysilanes were obtained as organosilanes with 15 and 2% of selectivity, respectively. The reaction of silicon, ethanol and ethylene resulted in 28% selectivity for ethyldiethoxysilane at 0.99 MPa of ethylene and 0.21 MPa of ethanol at 240°C.
- Okamoto, Masaki,Komai, Jun-Ichi,Uematsu, Miwa,Suzuki, Eiichi,Ono, Yoshio
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p. 235 - 240
(2007/10/03)
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- Catalysis of hydrosilylation: Part XXXIV. High catalytic efficiency of the nickel equivalent of Karstedt catalyst [{Ni(η-CH2=CHSiMe2)2O} 2{μ-(η-CH2=CHSiMe2)2O}]
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The nickel equivalent of Karstedt catalyst [{Ni(η-CH2=CHSiMe2)2O} 2{μ-(η-CH2=CHSiMe2)2O}] (1) appeared to be a very efficient catalyst for dehydrogenative coupling of vinyl derivatives (styrene, vinylsilanes, vinylsiloxanes) with trisubstituted silanes HSi(OEt)3, HSiMe2Ph. The reaction occurs via three pathways of dehydrogenative coupling, involving formation of an unsaturated compound as the main product as well as a hydrogenated olefin (DS-1) pathway, hydrogenated dimeric olefin (DS-2) and dihydrogen (DC), respectively. The reaction is accompanied by side hydrosilylation. Stoichiometric reactions of 1 with styrene and triethoxysilane, in particular synthesis of the bis(triethoxysilyl) (divinyltetramethyldisiloxane) nickel complex 3 and the first documented insertion of olefin (styrene) into Ni-Si bond of complex 3, as well as all catalytic data have allowed us to propose a scheme of catalysis of this complex reaction by 1.
- Maciejewski,Marciniec,Kownacki
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p. 175 - 181
(2007/10/03)
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- Continuous single-stage organomagnesium synthesis of a mixture of ethylethoxysilanes and dimethylethylethoxysilane
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Simultaneous synthesis of ethylethoxysilanes and dimethylethylethoxysilane from a mixture of ethyl chloride, tetraethoxysilane, and dimethyldichlorosilane with magnesium (supply rate 75-100 g h-1) was studied. Schemes of intermediate processes are proposed. Reactivity of dimethyldichlorosilane and diethyldichlorosilane relative to each other is evaluated. Various grades of magnesium are tested. To reduce the amount of regenerated solvent (toluene) its mixtures with oligodiethylsiloxanes are used. The mixture of ethyl-substituted silanes can be used in subsequent preparation of oligo-ethylsiloxane liquids modified with the terminal dimethylethylsiloxy groups, which are characterised by improved lubricating properties.
- Klokov, Boris A.
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p. 122 - 128
(2013/09/07)
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- Continuous and batch organomagnesium synthesis of ethyl-substituted silanes from ethylchloride, tetraethoxysilane, and organotrichlorosilane for production of polyethylsiloxane liquids. 1. Batch one-step synthesis of ethylethoxysilanes and ethylchlorosilanes
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Development of batch one-step manufacturing process for ethylethoxy- and ethylchlorosilanes is desribed. The methodology of synthesis of ethyl-substituted silanes has been improved. The important factors for the successful synthesis have been determined. Among them are the replacement of the part tetraethoxysilane 3 by ethyltrichlorosilane 10, the optimum concentration of 3 and 10 resulting in high yield of triethylsilanes, low duration of synthesis, and high selectivity of Grignard reagent. Batch one-step synthesis has been assimilated into industry (up to a scale 240 kg of magnesium) for production of oligoethylsiloxanes with the high content (>40%) of a terminal triethylsiloxy group. The rules for R/D process of the Grignard synthesis are described.
- Klokov, Boris A.
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- Process for preparing low-chloride or chloride-free alkoxysilanes
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A process for preparing an alkoxysilane with an acidic chloride content of less than 10 ppm by weight, comprising: reacting a chlorosilane with an alcohol in a water-free and solvent-free phase to form a product mixture containing alkoxysilane and residual acidic chloride, with removal of resultant hydrogen chloride from the product mixture, then adding liquid or gaseous ammonia, in an amount corresponding to a stoichiometric excess, based on the content of acidic chloride, to form an ammonia-containing product mixture, treating the ammonia-containing product mixture at a temperature between 10 and 50 DEG C., wherein the ammonia and acidic chloride undergo neutralization, to form a crude product, and optionally, then separating off a salt formed in the course of neutralization, from the crude product, and recovering the alkoxysilane by distilling the crude product.
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- Stepwise organomagnesium synthesis of mixtures of ethyletoxysilanes and ethylchlorosilanes
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Mixture of ethylethoxy- and ethylchlorosilanes was prepared in a toluene solution by successive reaction of magnesium with a mixture of ethyl chloride and tetraethoxysilane and then with a mixture of ethyl chloride and tetrachlorosilane.
- Klokov
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p. 1863 - 1865
(2007/10/03)
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- Continuous single-stage organomagnesium synthesis of a mixture of ethylethoxysilanes with methylethylphenylethoxysilane
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A continuous reaction of ethyl chloride, tetraethoxysilane, and methylphenyldichlorosilane with magnesium in toluene or in a mixture of toluene with oligoethylsiloxanes was performed in a column apparatus with a stirrer under conditions of counterflow of magnesium and the reagent mixture.
- Klokov
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p. 1587 - 1592
(2007/10/03)
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- Continuous organomagnesium synthesis of a mixture of ethylethoxysilanes and methylethyl(thienyl- or haloorgano)ethoxysilane
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Simultaneous synthesis of ethylethoxysilanes and methylethyl(thienyl- or haloorgano)ethoxysilane from a mixture of ethyl chloride, tetraethoxysilane, and methyl(thienyl- or haloorgano)dichlorosilane with magnesium (supply rate 75-100 g h-1) was studied. The mixture of these compounds can be used in subsequent preparation of oligoethylsiloxane liquids modified with the terminal methylethyl(thienyl- or haloorgano)siloxy groups, which are characterized by improved lubricating properties.
- Klokov
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p. 479 - 482
(2007/10/03)
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- Generation and reactivities of ethylmethoxysilylene
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Vacuum pyrolysis of 1,2-diethyl-1,1,2,2-tetramethoxydisilane (II) in the presence of 2,3-dimethyl-1,3-butadiene resulted in the formation of 1-ethyl-1-methoxy-(III), 1-ethyl-(IV), and 1-methoxy-3,4-dimethyl-1-silacyclopent-3-ene(V) along with ethyltrimethoxysilane. The observed products might be formed from the addition of ethylmethoxysilylene, ethylsilylene and methoxysilylene into 2,3-dimethyl-1,3-butadiene respectively under thermal conditions. A labelling experiment employing a deuterated precursor of 1,2-diethyl-1,1,2,2-tetramethoxy-d12-disilane (II-d12) was performed for the purpose of elucidating the conversion of ethylmethoxysilylene into ethylsilylene. Ethylsilylene might be generated from [3 → 2 + 1] cyclo-elimination of an intermediate of 2-ethyloxasilacyclopropane (EtHSi-O-CH2) which can arise from a possible intramolecular silylene insertion into a C-H bond of the methoxy group of ethylmethoxysilylene. The methoxysilylene might be formed from elimination of ethylene of 1-methoxy-1-silacyclopropane (HMeOSi-CH2-CH2) derived from intramolecular silylene insertion into a C-H bond of the ethyl group of ethylmethoxysilylene. The temperature dependence of the trapped adduct distribution from the pyrolysis of 1,2-diethyl,1,2,2-tetramethoxydisilane was examined.
- Kwak, Young-Woo,Lee, Kyung-Koo
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p. 219 - 225
(2007/10/03)
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- Competitive dehydrogenative silylation and hydrogenative dimerization of vinyltriethoxysilane catalyzed by the [Ni(acac)2] + PPh3 system, intermediate and mechanistic implications
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[Ni(acac)C2H5(PPh3)] (C) has been shown to be an essential intermediate in the reaction between HSi(OC2H5)3 and vinyltrisubstituted silanes catalyzed by the system [Ni(acac)2] + PPh3 at room temperature, but only after oxygenation of the coordinated triphenylphosphine. The stoichiometric and catalytic reactions of complex C with the substrates lead to catalysed, competitive dehydrogenative silylation and hydrogenative dimerization of vinylsilane, which occur following insertion of the latter into Ni-H, Ni-Si ≡ and Ni-C bonds.
- Marciniec,Maciejewski,Gulinski,Maciejewska,Duczmal
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p. 245 - 251
(2007/10/03)
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- Continuous Single-Stage Organomagnesium Synthesis of Ethylethoxysilanes and Ethylchlorosilanes from a Mixture of Tetraethoxysilane and Diethylchlorosilane
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Basic parameters are presented of novel highly efficient technology for the synthesis of organosilicon monomers for producing practically useful polyethylsiloxane liquids.
- Klokov, B. A.
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p. 100 - 104
(2007/10/03)
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- The Reaction of with Triethoxysilane in the Presence of PPh3: a New Method for Synthesis of
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The reaction of with triethoxysilane in the presence of PPh3 is examined under oxygen-free conditions, permitting isolation of 1 formed by elimination of one acac ligand (as protonated and hydrosilylated product) from the nickel complex with its simultaneous silylation which is followed by C-O bond cleavage in triethoxysilyl ligand via a mechanism involving transfer of an ethyl group to Ni with elimination of pentaethoxyhydrodisiloxane in the excess of triethoxysilane.
- Marciniec, Bogdan,Maciejewski, Hieronim,Gulinski, Jacek
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p. 717 - 718
(2007/10/02)
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- Conversion of Vinylsilanes in the Presence of Triethoxysilane Catalyzed by Ruthenium Complexes
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Reaction of vinylsilanes with triethoxysilane catalyzed by ruthenium phosphine and non-phosphine complexes proceed via several competitive-consecutive routes including hydrosilylation, metathesis, hydrogenation and dehydrogenative silylation as well as migration and oxygenation of silyl groups, ethene hydrosilylation and catalytic redistribution of triethoxysilane.Ruthenium hydride and/or ruthenium silyl complexes seem to play the role of key intermediates in all the processes mentioned above.Key words: ruthenium complexes, silyl complexes, hydride complexes, competitive-consecutive reaction
- Gulinski, J.
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p. 1266 - 1272
(2007/10/02)
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- Catalysis of hydrosilylation. Part XXV. Effect of nickel(0) and nickel(II) complex catalysts on dehydrogenative silylation, hydrosilylation and dimerization of vinyltriethoxysilane
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General catalysis by Ni(O) and Ni(II) phosphine and non-phosphine complexes of the competitive-consecutive reaction of vinyltriethoxysilane with triethoxysilane has been observed to give mainly products of dehydrogenative silylation and hydrogenative dimerization accompanied by products of regular hydrosilylation, disproportionation of substrates and secondary reactions of the product-bis(silyl)ethene.In an excess of vinylsilane, side reactions can be practically eliminated.Tertiary phosphine and phosphite ligands of nickel acetylacetonate (Ni(acac)2*2PR3) stop the consecutive reactions of bis(silyl)ethene but in the presence of ?-basic and bulky tricyclohexylphosphine the system catalyzes selectively the regular hydrosilylation of bis(silyl)ethene.Keywords: Nickel; Silicon; Hydrosilylation; Silane; Catalysis
- Marciniec, Bogdan,Maciejewski, Hieronim,Rosenthal, Uwe
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p. 147 - 152
(2007/10/02)
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- Catalysis of hydrosilylation XXIII. Effect of substituents at silicon on unusual hydrosilylation of vinylsilanes catalysed by nickel acetylacetonate
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Nickel acetylacetonate catalyses a competitive-consecutive reaction of trisubstituted silanes ((EtO)3SiH and Et3SiH) with a variety of vinyl-trisubstituted silanes, giving products of dehydrogenative silylation, hydrosilylation and hydrogenative oligimerization as well as of disproportionation of substrates and dehydrogenative silylation of bis(silyl)ethenes.The conversion, yield and selectivities of the reaction have been influenced by many factors such as electronic and steric effects of the substituents at silicon of both initial substrates, as well as by the vinyl:hydrosilane ratio, the temperature and the presence of dioxygen.
- Marciniec, Bogdan,Maciejewski, Hieronim
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- Catalysis of hydrosilylation. XX. Unusual reaction of vinyltriethoxysilane with triethoxysilane catalyzed by nickel acetylacetonate
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Nickel acetylacetonate is shown to be a catalyst of an unusual reaction of vinyltriethoxysilane with triethoxysilane involving formation of bis(silyl)ethene and bis(silyl)butanes as the main products accompanied by others of direct and dehydrogenative hydrosilylation, bis(silyl)ethane and ethylsilane as well as products of redistribution of triethoxysilane and formation of oligomers.The latter reaction is a consequence of consecutive oligomerization of bis(silyl)ethenes and other products.The effect of temperature, the concentration ratio of substrates and the catalyst, and other reaction conditions on the conversion and reaction yield led us to propose a scheme explaining the course of this competitive-consecutive reaction.
- Marciniec, Bogdan,Maciejewski, Hieronim,Mirecki, Janusz
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- SELECTIVE ON-LINE DEUTERATION IN GAS CHROMATOGRAPHY-MASS SPECTROMETRY FOR THE INVESTIGATION OF DISSOCIATIVE IONIZATION OF SILICON-CONTAINING COMPOUNDS
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A method for specific gas-phase deuteration of unsaturated silicon-containing compounds over pre-heterogenized Wilkinson's catalyst (a solution of (Ph3P)3RhCl in Carbowax 20M coated on Chromaton) in the reaction column connected to the mass spectrometer is described.This methode was employed to study the dissociative ionization of the corresponding saturated analogues.With the aid of the mass spectra of the dideutero derivatives thus obtained, the main electron-impact-induced reactions of 1,1-dimethyl-1-silacyclopentane, 1,1,2,2-tetramethyl-1,2-disilacyclohexane, 1-methyl-1-ethyl-1-silacyclobutane and ethyl triethoxysilane were elucidated.
- Mikaya, A. I.,Zaikin, V. G.,Ushakov, N. V.,Vdovin, V. M.
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- CATALYSIS OF HYDROSILYLATION. PART II. ADDITION OF TRIALKOXYSILANES TO VINYLTRIALKOXYSILANES CATALYZED BY TRANSITION METAL COMPLEXES
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Hydrosilylation of vinyltrialkoxysilanes by trialkoxysilanes catalyzed by various transition metal complexes: H2PtCl6, (PPh3)3RhCl, (PPh3)3RuCl2, Ru(acac)3, Ni(acac)2 was found to proceed giving mostly 1,2-bis(trialkoxysilyl)ethane (β-adduct) as the main product.In presence of ruthenium complexes, besides β-adduct, unsaturated product of dehydrogenative double hydrosilylation (RO)3SiCH=CHSi(OR)3 (where R=C2H5, iso-C3H7) was obtained as a by-product, except for trimethoxysilyl derivatives, where α-adduct was found.Addition of trialkoxysilane to vinyltrialkoxysilanecontaining different substituents at two silicon atoms proceeds via RO/R'O exchange of the successive substituents, followed by hydrosilylation of all vinylsilanes by all trisubstituted silanes.
- Marciniec, Bogdan,Gulinski, Jacek,Urbaniak, Wlodzimierz
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p. 287 - 296
(2007/10/02)
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