- Isolated SiH and GeH stretching frequencies and bond strength differences in cyclopropyl and cyclopentyl silanes and germanes
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Infrared gas phase spectra in the SiH and GeH stretching regions are reported for cyclopropyl-SiH3, -SiHD2, GeHD2, cyclopentyl-SiHD2 and -GeHD2.In each case two bands are seen which indicate the presence of stronger MHa and weaker MHs/sub
- McKean, D. C.,Morrisson, A. R.,Dakkouri, M.
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- Thermal hydrosilylation of olefin with hydrosilane. Preparative and mechanistic aspects
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The reaction of trichlorosilane (1a) at 250 °C with cycloalkenes, such as cyclopentene (2a), cyclohexene (2b), cycloheptene (2c), and cyclooctene (2d), gave cycloalkyltrichlorosilanes [CnH2n-1SiCl3: n = 5 (3a), 6 (3b), 7 (3c), 8 (3d)] within 6 h in excellent yields (97-98%), but the similar reactions using methyldichlorosilane (1b) instead of 1a required a longer reaction time of 40 h and afforded cycloalkyl(methyl)dichlorosilanes [CnH2n-1SiMeCl2: n = 5 (3e), 6 (3f), 7 (3g), 8 (3h)] in 88-92% yields with 4-8% recovery of reactant 2. In large (2, 0.29 mol)-scale preparations, the reactions of 2a and 2b with 1a (0.58 mol) under the same condition gave 3a and 3b in 95% and 94% isolated yields, respectively. The relative reactivity of four hydrosilanes [HSiCl3-mMem: m = 0-3] in the reaction with 2a indicates that as the number of chlorine-substituent(s) on the silicon increases the rate of the reaction decreases in the following order: n = 3 > 2 > 1 ? 0. In the reaction with 1a, the relative reactivity of four cycloalkenes (ring size = 5-8) decreases in the following order: 2d > 2a > 2c > 2b. Meanwhile linear alkenes like 1-hexene undergo two reactions of self-isomerization and hydrosilylation with hydrosilane to give a mixture of the three isomers (1-, 2-, and 3-silylated hexanes). In this reaction, the reactivity of the terminal 1-hexene is higher than the internal 2- and 3-hexene. The redistribution of hydrosilane 1 and the polymerization of olefin 2 occurred rarely under the thermal reaction condition.
- Jung, Dong Euy,Han, Joon Soo,Yoo, Bok Ryul
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experimental part
p. 3687 - 3692
(2011/11/29)
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- Trichlorosilyl groups containing organochlorosilanes and their preparation methods by the double-silylation of olefins with trichlorosilane
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The present invention provides organosilicon compounds containing two trichlorosilyl groups and their preparation methods. Organosilicon compounds of formula II are prepared by reacting linear chain or cyclic olefins of formula I with trichlorosilane in the presence of quaternary organophosphonium salt as a catalyst.R1—HC=CH—R2??(I) 1In formulas I and II, R1 and R2 may be identical or different and represent a hydrogen atom, a linear or a cyclic C1-C8 alkyl, a linear or a cyclic C1-C8 alkenyl, benzyl, phenyl, a C1-C8 alkyl substituted phenyl group, two functional groups between R1 and R2 may be covalently bonded to form a C4-C8 ring with or without a carbon-carbon double bond.
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- Organosilicon derivatives of cyclopentane
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Addition of HMe3-nSiCln (n = 1-3) to cyclopentene yields the corresponding cyclopentylchloro-silanes. Their ethynyl derivatives were prepared by the reaction with ethynylmagnesium bromide. The reaction of cyclopentyldimethyl(bromomagnesioethynyl)silane with acetaldehyde gives 1-(cyclopentyldimethylsilyl)-1-butyn-3-ol. When treated with EtMgBr and Me3SiCl, cyclopentyltriethynylsilane gives cyclopentyldiethynyl-(trimethylsilylethynyl)silane. The reaction between cyclopentyltrichlorosilane and methanol produces cyclopentyltrimethoxysilane, and the reaction of the latter with triethanolamine gives cyclopentylsilatrane.
- Yarosh,Mirskov,Yarosh,Albanov,Voronkov
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p. 242 - 244
(2007/10/03)
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- Silane compound and processes for the preparation thereof
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Novel silane compound, alkoxy cyclopentyl diethoxysilane, is prepared by reacting cyclopentyl trihalosilane with ROH and then with ethanol, or by reacting cyclopentyl triethoxysilane with ROH, wherein alkyl in the alkoxy or R in ROH stands for an organic group selected from tile group consisting of isopropyl, sec-butyl, tert-buryl and tert-amyl groups. The silane compounds are useful as a catalytic component for olefin polymerization and as a silane coupling agent.
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- Silane compound and processes for the preparation thereof
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Novel silane compound, alkoxy cyclopentyl dimethoxysilane, is prepared by reacting cyclopentyl trihalosilane with ROH and then with methanol, or by reacting cyclopentyl trimethoxysilane with ROH, wherein alkyl in the alkoxy or R in ROH stands for an organic group selected from the group consisting of sec-butyl, tert-amyl, cyclopentyl, oxa-3-cyclopentyl, cyclohexyl and 2-isopropyl-5-methyl cyclohexyl groups. The silane compounds are useful as a catalytic component for olefin polymerization and as a silane coupling agent.
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- Silane compound and processes for the preparation thereof
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Novel silane compounds, tert.-butoxy cyclopentyl dimethoxysilane and isopropoxy cyclopentyl dimethoxysilane, are prepared by reacting cyclopentyl trihalosilane with ROH (where R stands for tert.-butyl or isopropyl group) and then with methanol, or by reacting cyclopentyl trimethoxysilane with ROH. The silane compounds are useful as a catlaytic component for olefin polymerization and as a silane coupling agent.
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- Method for the preparation of cyclopentyl trichlorosilane
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Cyclopentyl trichlorosilane can be efficiently prepared by the hydrosiliaton reaction of trichlorosilane and cyclopentene which can proceed only to a very low extent by the use of conventional platinum catalysts effective in other hydrosilation reactions. Thus, an equimolar mixture of the reactants is heated in the presence of a chlorine-deficient chloroplatinic acid catalyst of a specified chlorine:platinum atomic ratio at a temperature higher than the boiling point of the mixture under normal pressure in a pressurizable vessel so that the desired product can be obtained in a yield of 90% of the theoretical value or higher.
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- A method for the preparation of a cycloalkyl silane compound
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Cycloalkyl silane compound such as cyclohexyl methyl di-chlorosilane can be efficiently prepared by the photochemically induced hydrosilylation reaction. For example, an equimolar mix-ture of cyclohexene and methyl dichlorosilane and admixture of a catalytic amount of a platinum compound, e.g., chloroplatinic acid, is irradiated at a temperature up to 70 °C with ultraviolet light so that the hydrosilylation reaction takes place and proceeds almost to completeness without deactivation of the platinum catalyst to give the desired product in a yield of 90% or even higher.
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- Kinetics of the Gas-phase Addition Reactions of Trichlorosilyl Radicals. Part 3.-Additions to 2-Olefins
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The following Arrhenius parameters for the forward and reverse steps of trichlorosilyl radical additions to trans-but-2-ene, cis-but-2-ene, cis-pent-2-ene, 2-methyl-but-2-ene and cyclopentene have been obtained by a competitive method.The relevant elementary reactions are .SiCl3 + CH3COCH3 --> (CH3)2C.OSiCl3 (3) .SiCl3 + >C=C >C.-C-SiCl3 (5,-5) and >C.-C-SiCl3 + HSiCl3 --> HC-C-SiCl3 + .SiCl3 (6). The rate parameters of reaction (5) are expressed per reaction site; an asterisk indicates the site of addition in an unsymmetrical olefin.Evaluted values of A-5 and A5 imply a fairly 'loose' transition state in reaction (5).The Si-C bond energy has been estimated. .SiCl3 radicals have been revealed to be electrophilic and susceptible to steric hindrance.
- Dohmaru, Takaaki,Nagata, Yoshio
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p. 1141 - 1148
(2007/10/02)
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