- Thermal reaction of cyclic alkadiene with trichlorosilane. Preparative and mechanistic aspects
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The thermal reactions of trichlorosilane (1a) with cyclic alkadienes such as cyclopentadiene (2a), 1,3-cyclohexadiene (2b), and 1,4-cyclohexadiene (2c) were studied at temperatures ranging from 170 °C to 250 °C. In this reaction, the hydrosilylation rate increased as the reaction temperature was raised using an equimolar ratio of 1a to 2a. The reaction of 2a with 1a at 250 °C afforded 2-cyclopentenyltrichlorosilane (3a) as the major hydrosilylation product within 1 h in good yield (82%). This reaction also works when dicyclopentadiene (2a′) was used as a reactant instead of 2a. In a large scale preparation under the same conditions, 3a was obtained in 82% isolated yield. It is significant to note that 2a′ can be used for the hydrosilylation, with no requirement of a cracking step under our thermal conditions. While the reaction of cyclohexadienes with 1a under the same conditions gave a mixture of three hydrosilylation products such as 2-cyclohexenyltrichlorosilane (3b), 3-cyclohexenyltrichlorosilane (3c) and cyclohexyltrichlorosilane (5) in moderate yields, along with other unsaturated C6 components, such as benzene and cyclohexene. In the thermal reaction of cycloalkadienes with 1a, the five-membered-ring diene 2a undergoes both a hydrosilylation reaction with 1a as well as a [4 + 2] cycloaddition reaction, leading to the hydrosilylation product 3a in good yield. While the six-membered ring dienes, 2b and 2c, undergo four different types of reactions, including hydrosilylation, [4 + 2] cycloaddition, dehydrogenation, and hydrogenation in competition to give the hydrosilylation products, hexane, and benzene, respectively. The reaction rates of cyclic alkadienes under our thermal conditions increase in the following order: 2c 2b 2a.
- Jung, Dong Eui,Han, Joon Soo,Yoo, Bok Ryul
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- Cyclohexadien-2,4-ylsilane and its derivatives, synthesis of the same, and the pyrolysis of the same to silane
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Silane gas precursor compounds having the formula (I): wherein R1, R2, and R3 each can independently be hydrogen or halogen and wherein the cyclohexadiene ring can have one or more substituents selected from the group consisting of a saturated or unsaturated, straight chain or branched alkyl group, a halogen, NO2, and C≡N are disclosed. In one form, the silane gas precursor compound is cyclohexadien-2,4-ylsilane, an air-stable liquid, that can be thermolyzed in a pyrolysis process to efficiently generate high purity silane gas. The compounds of the present invention can thus serve as a “point-of-use” precursor for silane gas.
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(2008/06/13)
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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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