- Trimethyl- and trichlorosilylcobalt tetracarbonyls and the hydrosilation of ethylene
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The new compound (CH3)3SiCo(CO)4 was synthesized by the reaction of (CH3)3SiH with either Co2(CO)8 or HCo(CO)4. The interaction of Cl3SiH or CH3S
- Baay, Yvonne Louise,MacDiarmid, Alan G.
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- Preparation of Hexafluorodisilane and Reactions of Hexafluorodisilane and Hexachlorodisilane with Sulfur Trioxide
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Hexafluorodisilane has been prepared by the fluorination of hexachlorodisilane or hexabromodisilane by potassium fluoride in boiling acetonitrile, in yields approximating 45 and 60percent respectively.Hexafluorodisilane has been characterised by infrared
- Suresh, Bettadapura Srinivasaiah,Padma, Doddaballapur Krishnamurthy
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- Tris(trichlorosilyl)tetrelide Anions and a Comparative Study of Their Donor Qualities
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Trichlorosilylated tetrelides [(Cl3Si)3E]? have been prepared by adding 1 equiv of a soluble Cl? salt to (Cl3Si)4Si (E=Si) or 4 Si2Cl6/GeCl4 (E=Ge). To asse
- Teichmann, Julian,Kunkel, Chantal,Georg, Isabelle,Moxter, Maximilian,Santowski, Tobias,Bolte, Michael,Lerner, Hans-Wolfram,Bade, Stefan,Wagner, Matthias
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- Nonclassical complex of dichlorosilylene with CO: direct spectroscopic detection
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A complex between SiCl2 and CO of the 1:1 composition with coordination of the silylene to the C atom of carbon monoxide is detected in Ar matrices using FTIR spectroscopy. A positive shift of the ν(CO) band of the complex relative to the corre
- Boganov, S. E.,Egorov, M. P.,Lalov, A. V.,Promyslov, V. M.,Syroeshkin, M. A.
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- Interactions of chloromethyldisilanes with tetrakis(dimethylamino)ethylene (TDAE), formation of [TDAE] [Si3Me2Cl7]
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The chlorodisilanes SiClMe2-SiClMe2 (1), SiCl2Me-SiCl2Me (2), SiCl3-SiCl3 (3) and a 9:1 mixture of 2 and SiCl3-SiCl2Me (4) were reacted with the electron-rich alkene tetrakis-(dimethylamino)-ethylene (TDAE) in n-hexane as well as in polar solvents. While 1 gave no reaction at all, 3 underwent a disproportionation reaction into SiCl4 and Si(SiCl3)4. Also 2 and mixtures of 2 and 4 were disproportionated into MeSiCl3 (2a) and methylchlorooligosilanes. Additionally a crystalline mixture of Si3Me3Cl6 -TDAE (5a) plus Si3Me2Cl7 -TDAE (5b) was obtained by reaction of a 9:1 mixture of 2 and 4 with TDAE in n-hexane as well as in 1,2-dimethoxyethane. The reaction of 2 with TDAE in acetonitrile (MeCN) led to a crystalline precipitation of [TDAE]Cl2 -MeCN (6.MeCN) in addition to MeSiCl3 and methylchlorooligosilanes. The structures of 5b and 6.MeCN were determined by X-ray crystallography beside their NMR and IR spectroscopic characterization. Compound 5b crystallizes in the monoclinic space group P2/c (Z = 4), 6.MeCN in the orthorhombic space group Pna21 (Z = 4). The structure of 5b reveals a [TDAE].+ radical cation and a 1, 2-Me2Si3Cl7- anion with a pentacoordinated central silicon atom.
- Knopf,Herzog,Roewer,Brendler,Rheinwald,Lang
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- Si-C coupling reaction of polychloromethanes with HSiCl3 in the presence of Bu4PCl: Convenient synthetic method for bis(chlorosilyl)methanes
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Coupling reaction of polychloromethanes CH4-nCln (n = 2-4) with HSiCl3 in the presence of tetrabutylphosphonium chloride (Bu4PCl) as a catalyst occurred at temperatures ranging from 30 °C to 150 °C. The reactivity of polychloromethanes increases as the number of chlorine-substituents on the carbon increases. In the reactions of CCl4 with HSiCl3, a variety of coupling products such as bis(chlorosilyl)methanes CH2(SiCl3)(SiXCl2) [X = Cl (1a), H (1b)], (chlorosilyl)trichloromthanes Cl3CSiXCl2 [X = Cl (2a), H (2b)], and (chlorosilyl)dichloromthanes Cl2HCSiXCl2 [X = Cl (3a), H (3b)] were obtained along with reductive dechlorination products such as CHCl3 and CH2Cl2 depending on the reaction temperature. In the reaction of CCl4, 2a is formed at the initial stage of the coupling reaction and converted to give CHCl3 at low temperature of 30 °C, to give 1a, 3a, and CHCl3 at 60 °C, and to afford 1a as major product and CH2Cl2 in competition above 100 °C. Si-H bond containing silylmethanes can be formed by the H-Cl exchange reaction with HSiCl3. Reaction of CHCl3 with HSiCl3 took placed at 80 °C to give three compounds 1a, 3a, and CH2Cl2, and finally 3a was converted to give 1a and CH2Cl2 at longer reaction time. While the condition for the reaction of CH2Cl2 with HSiCl3 required a much higher temperature of 150 °C. Under the optimized conditions for synthesizing bis(chlorosilyl)methanes 1a,b, a mixture of 1a and 1b were obtained as major products in 65% (1a:1b = 64:1) and 47% (42:5) yields from the reaction of CCl4 and CHCl3 at 100 °C for 8 h, respectively, and in 41% (34:7) yield from that of CH2Cl2 at 170 °C for 12 h. In the Si-C coupling reaction of polychloromethanes with HSiCl3, it seems likely that a trichlorosilyl anion generated from the reaction of HSiCl3 with Bu4PCl is an important key intermediate.
- Jung, Dong Euy,Kang, Seung-Hyun,Han, Joon Soo,Lim, Weon Cheol,Park, Young-ae W.,Yoo, Bok Ryul
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- A vapor-solid strategy to silica sheathed metal nanostructures and microstructures via reactions of metal chlorides with silicon
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A facile vapor-solid strategy has been developed to prepare silica-sheathed metal micro/nanostructures with controllable shapes. As examples, silica-sheathed nickel nanowires (diameter ~50 nm), microcubes (edge length 1-3 μm), nanocubes (edge length ~200 nm) with an epitaxial tail (diameter 2 structures are discussed. The method is expected to be applied to a wider range of metals.
- Wang, Jin,Zhang, Haoxu,Ge, Jianping,Li, Yadong
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- Etching of hexagonal SiC surfaces in chlorine-containing gas media at ambient pressure
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The modification of the silicon carbide (4H-SiC) single-crystal surface in a chlorine-containing gas mixture at high temperature (800-1000 °C) and ambient pressure was investigated. The results of silicon carbide chlorination are found to strongly depend on the hexagonal surface orientation. Due to the thermodynamically more favorable reaction of chlorine with silicon rather than carbon, the C-terminated side ( 0 0 0 over(1, -) ) clearly undergoes considerable changes, resulting in coverage by a black-colored carbon film, whereas the Si-side (0 0 0 1) surprisingly remains visually untouched. With using X-ray photoelectron spectroscopy (XPS), angle-resolved XPS and SEM it is shown that this drastic change in behavior is associated with a different structure of oxicarbide/silicate adlayer formed on the C- and Si-terminated sides of silicon carbide surface during experimental pre-treatment and air exposure. The presence of oxygen bridges connecting the silicate adlayer with the bulk SiC in the case of Si-side inhibits the chlorination reaction and makes this surface strongly resistant to chlorine attack. Only some places on the Si-terminated side demonstrate traces of chlorine etching in the form of hexagonal-shaped voids, which are possibly initiated by distortion of the initial crystalline structure by micropipes. In contrast, a thin carbon layer resulted on the C-terminated side as a consequence of the chlorination process. XPS, ARXPS, SEM and Raman spectroscopy study of created film allows us to argue that it consists mainly of sp2-bonded carbon, mostly in the form of nanoscale graphene sheets. The absence of a protective oxygen bridge between the silicate adlayer and the bulk silicon carbide crystal leads to unlimited growth of carbon film on the SiC ( 0 0 0 over(1, -) ) side.
- Zinovev,Moore,Hryn,Pellin
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- Reactivity of Cu3Si of different genesis towards copper(I) chloride
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A comparative study of the reactivity between copper(I) chloride and three types of Cu3Si obtained in a molten medium (Cu3Si-Ref) and from mechanical activation following an annealing process (Cu3Si-M2AP) or a self-propagating high-temperature synthesis (Cu3Si-MASHS) was performed by thermogravimetry under vacuum using non-isothermal and isothermal methods of kinetic measurement. It was established that for the three Cu3Si/CuCl systems, the acceleration and decay stages in the temperature range 145-215°C are very closely approximated by an equation of the Prout-Tompkins type where an autocatalytic process was proposed. The lower apparent activation energy obtained for the Cu3Si-MASHS/CuCl system (63 kJ mol-1 against 68 and 78 kJ mol-1 for Cu3Si-M2AP and Cu3Si-Ref, respectively) has been attributed to a small grain size which induces nanoscale contacts between reactants and impedes CuCl to sublime. (C) 2000 Elsevier Science B.V.
- Souha,Bernard,Gaffer,Gillot
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- Kinetics and Mechanism of the Gas Phase Thermal Decomposition of Hexachlorodisilane in the Presence of Iodine
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The gas phase thermal reaction of Si2Cl6 with I2 has been investigated.Product analysis reveals the formation of SiCl4 and SiCl2I2.The reaction rate was found to obey the rate equation -dI
- Doncaster, Alan M.,Walsh, Robin
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- A Mild One-Pot Reduction of Phosphine(V) Oxides Affording Phosphines(III) and Their Metal Catalysts
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The metal-free reduction of a range of phosphine(V) oxides employing oxalyl chloride as an activating agent and hexachlorodisilane as reducing reagent has been achieved under mild reaction conditions. The method was successfully applied to the reduction of industrial waste byproduct triphenylphosphine(V) oxide, closing the phosphorus cycle to cleanly regenerate triphenylphosphine(III). Mechanistic studies and quantum chemical calculations support the attack of the dissociated chloride anion of intermediated phosphonium salt at the silicon of the disilane as the rate-limiting step for deprotection. The exquisite purity of the resultant phosphine(III) ligands after the simple removal of volatiles under reduced pressure circumvents laborious purification prior to metalation and has permitted the facile formation of important transition metal catalysts.
- Kapu?niak, ?ukasz,Plessow, Philipp N.,Trzybiński, Damian,Wo?niak, Krzysztof,Hofmann, Peter,Jolly, Phillip Iain
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supporting information
p. 693 - 701
(2021/04/06)
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- Silicon Tetrakis(trifluoromethanesulfonate): A Simple Neutral Silane Acting as a Soft and Hard Lewis Superacid
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A facile synthesis and isolation of pristine silicon tetrakis(trifluoromethanesulfonate), Si(OTf)4, is reported, acting as the first neutral silicon-based Lewis superacid suitable towards soft and hard Lewis bases. Its OTf groups have a dual function: they are excellent leaving groups and modulate the degree of reactivity towards soft and hard Lewis bases. Exposed to soft Lewis donors, Si(OTf)4 leads to [L2Si(OTf)4] complexes (L=isocyanide, thioether and carbonyl compounds) with retention of all Si?OTf bonds. In contrast, it can cleave C?X bonds (X=F, Cl) of hard organic Lewis bases with a high tendency to form SiX4 (X=F, Cl) after halide/triflate exchange. Most notable, Si(OTf)4 allows a gentle oxydefluorination of mono- and bis(trifluoromethyl)benzenes, resulting in the formation of the corresponding benzoylium species, which are stabilized by the weakly coordinating [Si(OTf)6] dianion.
- Driess, Matthias,Hermannsdorfer, André
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supporting information
p. 13656 - 13660
(2021/05/03)
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- Method for producing chloropropyltrichlorosilane
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The invention provides an industrial production method of trichloro(3-chloropropyl)silane. A trichloro(3-chloropropyl)silane addition reaction coarse product is used as reaction substrates; the raw material reactants of chloropropene and trichlorosilane a
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Paragraph 0038-0049; 0053-0059
(2020/03/14)
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- DISILANE-, CARBODISILANE-AND OLIGOSILANE CLEAVAGE WITH CLEAVAGE COMPOUND ACTING AS CATALYST AND HYDROGENATION SOURCE
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The invention relates to a process for the manufacture of monosilanes of formula (I): MexSiHyClz (I), comprising: the step of subjecting a silane substrate (methyldisilanes, methyloligosilanes, or carbodisilanes) to a cleavage reaction of the silicon-silicon bond(s) or the silicon- carbon bonds in silane substrates the reaction involving a cleavage compound selected from a quaternary Group 15 onium compound R4 QX, a heterocyclic amine, a heterocyclic ammonium halide, or a mixture of R3P and RX. The starting material disilanes to be cleaved has the formula (II): MemSi2HnClo (II) The starting material oligosilanes to be cleaved have the general formula (III): MepSiqHrCIs (II I), The starting material carbodisilanes to be cleaved have the general formula (IV): (MeaSiHbCle)-CH2-(MecSiHdClf) (IV)
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(2019/04/16)
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- Formation of 1,1-dichloro-2-vinyl-1-silacyclopropane by a photoinduced reaction between dichlorosilylene and 1,3-butadiene
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A matrix FTIR study of interaction between SiCl2 and 1,3-butadiene revealed that at low temperatures, it stops at the step of complexation between the reactants. This allowed us to investigate a photochemical version of this interaction resulti
- Boganov, Sergey E.,Promyslov, Vladimir M.,Rynin, Stanislav S.,Krylova, Irina V.,Egorov, Mikhail P.
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p. 574 - 576
(2018/12/13)
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- Trapping Experiments on a Trichlorosilanide Anion: A Key Intermediate of Halogenosilane Chemistry
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Treatment of Si2Cl6 with [Et4N][BCl4] in CH2Cl2 furnished the known products of a chloride-induced disproportionation reaction of the disilane, such as SiCl4, [Si(SiCl3)3]-, and [Si6Cl12·2Cl]2-. No Si-B-bonded products were detectable. In contrast, the addition of Si2Cl6 to [Et4N][BI3Cl] afforded the Si-B adduct [Et4N][I3SiBI3]. Thus, a quantitative Cl/I exchange at the silicon atom accompanies the trihalogenosilanide formation. [Et4N][I3SiBI3] was also accessible from a mixture of Si2I6, [Et4N]I, and BI3. According to X-ray crystallography, the anion [I3SiBI3]- adopts a staggered conformation with an Si-B bond length of 1.977(6) ?. Quantum-chemical calculations revealed a polar covalent Si-B bond with significant contributions from intramolecular I···I dispersion interactions.
- Teichmann, Julian,Bursch, Markus,K?stler, Benedikt,Bolte, Michael,Lerner, Hans-Wolfram,Grimme, Stefan,Wagner, Matthias
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p. 8683 - 8688
(2017/08/14)
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- Gamma-chloropropyltrichlorosilane production method and system
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The invention provides a gamma-chloropropyltrichlorosilane production method and system. The production system comprises a tubular reactor, a tank reactor of which an inlet is communicated with an outlet of the tubular reactor and a first outlet is communicated with a first inlet of the tubular reactor, and a rectification device of which an inlet is communicated with a second outlet of the tank reactor. Compared with the existing production system, the production system provided by the invention returns a part of a crude product in the tank reactor to the tubular reactor and an activated catalyst starts a reaction so that a catalyst starting process is avoided, reaction time is shortened and a catalyst use amount is reduced. A part of the crude product in the tank reactor is returned to the tubular reactor and a temperature in the tubular reactor is kept by heat so that energy consumption is reduced. Through control of a reaction temperature in the tubular reactor, reaction selectivity is improved. A reaction temperature in the tank reactor is improved so that the reaction is full.
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Paragraph 0045; 0046; 0047; 0048; 0049; 0050; 0051; 0052
(2016/10/10)
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- Method for preparing silicon—sulfur compounds and their use in bitiminous compositions
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A method of producing sulfur modified organosilane compounds that can be used in asphalt binders which method involves: combining together an organosilane or mixtures of organosilanes, a sulfide, a halogen acceptor and solvent to form a reaction mixture; and allowing the organosilane to react with the sulfide in the presence of a halogen acceptor to produce a sulfur modified organosilane compound. The sulfur modified organosilane compound can be introduced into a polymer modified or unmodified asphalt binder in which the sulfur modified organosilane compound reacts with components in the asphalt mixture to form a modified asphalt. The organosilanes used to produce the sulfur modified organosilanes can be from a source of waste products (such as Direct Product Residue) in which case the waste products can be reused in asphalt binders.
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(2015/08/03)
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- Amorphous silicon: New insights into an old material
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Amorphous silicon is synthesized by treating the tetrahalosilanes SiX4 (X=Cl, F) with molten sodium in high boiling polar and non-polar solvents such as diglyme or nonane to give a brown or a black solid showing different reactivities towards suitable reagents. With regards to their technical relevance, their stability towards oxygen, air, moisture, chlorine-containing reaction partners RCl (R=H, Cl, Me) and alcohols is investigated. In particular, reactions with methanol are a versatile tool to deliver important products. Besides tetramethoxysilane formation, methanolysis of silicon releases hydrogen gas under ambient conditions and is thus suitable for a decentralized hydrogen production; competitive insertion into the MeO-H versus the Me-OH bond either yields H- and/or methyl-substituted methoxy functional silanes. Moreover, compounds, such as MenSi(OMe)4-n (n=0-3) are simply accessible in more than 75% yield from thermolysis of, for example, tetramethoxysilane over molten sodium. Based on our systematic investigations we identified reaction conditions to produce the methoxysilanes MenSi(OMe)4-n in excellent (n=0:100%) to acceptable yields (n=1:51%; n=2:27%); the yield of HSi(OMe)3 is about 85%. Thus, the methoxysilanes formed might possibly open the door for future routes to silicon-based products. Amorphous silicon is easily synthesized from tetrahalosilanes SiX4 (X=Cl, F) and molten sodium in different solvents. Reactivity studies prove the resulting materials as versatile tools for the formation of technical important silanes, such as the silicon chloro-, alkoxy-, and methylalkoxy-substituted derivatives (see figure; bl=black, br=brown).
- Spomer, Natalie,Holl, Sven,Zherlitsyna, Larissa,Maysamy, Fariba,Frost, Andreas,Auner, Norbert
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p. 5600 - 5616
(2015/03/30)
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- PROCESS FOR SELECTIVE PRODUCTION OF HALOSILANES FROM SILICON-CONTAINING TERNARY INTERMETALLIC COMPOUNDS
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A process includes contacting an organohalide with a ternary intermetallic compound at a temperature of 300 °C to 700 °C to form a reaction product including a halosilane. The ternary intermetallic compound includes three metals. The first metal is Cu or Mg; the second metal is Au, Ni, or Pd; and the third metal is Si.
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Paragraph 0043
(2014/08/06)
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- PROCESS FOR THE PRODUCTION OF SILANE PRODUCTS FROM CALCIUM SILICIDE
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A process for preparing a reaction product including a silane product includes step (i), (ii), and (iii). Step (i) is contacting an organohalide with a calcium silicide at a temperature from 300 °C to 700 °C to form the reaction product including a spent reactant and the silane product. The silane product has formula RmHnSiX(4-m-n), where each R is independently a monovalent organic group, each X is independently a halogen atom; subscript m is 0 to 4; subscript n is 0 to 2; and a quantity (m + n) is 0 to 4. Step (ii) is contacting, at a temperature from 200 °C to 1400 °C, the spent reactant with a silane of formula HaRbSiX(4-a-b), where subscript a is 0 to 4, subscript b is 0 or 1, a quantity (a + b) ≤ 4. The silane of formula HaRbSiX(4-a-b) is distinct from the silane product of formula RmHnSiX(4-m-n). When the quantity (a + b) 2; thereby forming a reactant. Step (iii) is contacting the reactant formed in step (ii) with an additional organohalide at a temperature from 300 °C to 700 °C to form an additional silane product of formula RmHnSiX(4-m-n). Steps (ii) and (iii) are performed separately and consecutively after step (i).
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Paragraph 0052
(2014/11/11)
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- ALTERNATIVE METHODS FOR THE SYNTHESIS OF ORGANOSILICON COMPOUND
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A method of forming chloro-substituted silanes from the reaction of an alkoxysilane with a chlorinating agent in the optional presence of a catalyst is provided. More specifically, chloro-substituted silanes, including but not limited to silicon tetrachloride, are formed by reacting a chlorinating agent, such as thionyl chloride, with an alkylalkoxysilane having the formula (R'0)4-xSiRx, where R and R' are independently selected alkyl groups comprising one or more carbon atoms and x is 0, 1, 2, or 3. The catalyst may be dimethylformamide, (chloromethylene)dimethyliminium chloride, or triethylamine, among others. The chloro- substituted silane formed in the reaction along with several by-products has the formula (RO)4-x-ySiRxCly; where x is 0, 1, 2, or 3 and y is 1, 2, 3, or 4. One of the by-products of the reaction is an alkyl chloride.
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Paragraph 0074-0076
(2013/09/26)
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- Alternative methods for the synthesis of organosilicon compounds
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A method of forming chloro-substituted silanes from the reaction of an alkoxy-or acetoxy-substituted silane with a chlorinating agent in the optional presence of a catalyst is provided. For instance, chloro-substituted silanes, including but not limited to silicon tetrachloride, are formed by reacting a chlorinating agent, such as thionyl chloride, with an alkoxysilane having the formula (R'O)4-xSiRx, where R and R' are independently selected alkyl groups comprising one or more carbon atoms and x is 0, 1, 2, or 3. The catalyst may be dimethylformamide, (chloromethylene)dimethyliminium chloride, or triethylamine, among others. The chloro-substituted silane formed in the reaction along with several by-products has the formula (R'O)4-x-ySiRxCly; where x is 0, 1, 2, or 3 and y is 1, 2, 3, or 4. One of the by-products of the reaction is an alkyl chloride.
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Paragraph 0042; 0074-0076
(2013/09/26)
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- Mechanistic insights into the hydrosilylation of allyl compounds - Evidence for different coexisting reaction pathways
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The hydrosilylation of allyl compounds is often accompanied by the formation of high amounts of byproducts. The formation processes have not been fully understood so far. In this work, the allyl hydrosilylation mechanism is investigated in detail and experimental and theoretical evidence for multiple, coexisting reaction pathways is provided. Based on earlier reports and the observations during an extensive catalytic study, different pathways, leading to the observed byproducts, were identified and proven by labeling experiments and DFT calculations. Oxidative addition of the silane and the insertion of the allyl compound into the Pt-H bond turned out to be the crucial, selectivity-determining steps within the catalytic cycle. Based on these findings, it should be possible to systematically influence these steps and pave the way to a rational and straightforward design of more selective catalysts.
- Gigler, Peter,Drees, Markus,Riener, Korbinian,Bechlars, Bettina,Herrmann, Wolfgang A.,Kuehn, Fritz E.
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- PROCESS FOR PREPARING ORGANOSILANES
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The invention relates to a process for preparing diorganyldihalosilanes of the general formula (1) R2SiX2 (1), in which dihalodihydrosilanes of the general formula (2) X2SiH2 (2), in a mixture with silanes of the general formula (3) R′3SiH (3), are reacted with halogenated hydrocarbons of the general formula (4) R-X (4), in the presence of a free-radical initiator, which is selected from alkanes, diazenes and organodisilanes, where R is a monovalent C1-C18 hydrocarbon radical, R′ is a monovalent C1-C18 hydrocarbon radical, hydrogen or halogen, and X is halogen.
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Page/Page column 3
(2012/12/13)
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- METHOD OF MAKING A TRIHALOSILANE
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A method of making a trihalosilane comprising contacting an organotrihalosilane according to the formula RS1X3 (I), wherein R is C1-C10 hydrocarbyl and each X independently is halo, with hydrogen, wherein the mole ratio of the organotrihalosilane to hydrogen is from 0.009:1 to 1:2300, in the presence of a catalyst comprising a metal selected from (i) Re, (ii) a mixture comprising Re and at least one element selected from Pd, Ru, Mn, Cu, and Rh, (iii) a mixture comprising Ir and at least one element selected from Pd and Rh, (iv) Mn, (v) a mixture comprising Mn and Rh, (vi) Ag, (vii) Mg, and (viii) Rh at from 300 to 800 °C to form a trihalosilane.
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Page/Page column 28-29
(2012/06/30)
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- METHOD OF PREPARING AN ORGANOHALOSILANE
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A method of preparing organohalosilanes comprising combining an organohalide having the formula RX (I), wherein R is a hydrocarbyl group having 1 to 10 carbon atoms and X is fluoro, chloro, bromo, or iodo, with a contact mass comprising at least 2% (w/w) of a palladium suicide of the formula PdxSiy (II), wherein x is an integer from 1 to 5 and y is 1 to 8, or a platinum suicide of formula PtzSi (III), wherein z is 1 or 2, in a reactor at a temperature from 250 to 700 °C to form an organohalosilane.
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Page/Page column 10-11
(2011/08/21)
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- Continuous Preparation of Organosilanes
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The invention relates to a process for the continuous preparation of organosilanes in a reactive distillation column, wherein a homogenous hydrosilylation catalyst is introduced into the column.
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Page/Page column 4-5
(2008/06/13)
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- Process For Preparing Si-H-Containing Silanes
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Silanes of the general formula (1) [in-line-formulae]RaSiHbX4-b-a ??(1)[/in-line-formulae] are prepared by disproportionating at least one more highly chlorinated silane in the presence of a homogeneous catalyst in an apparatus with at least one reactive distillation column and at least one additional reactor selected from among prereactors and side reactors, where R is an alkyl, aryl, alkaryl or haloalkyl radical, X is a halogen atom, a is 0 or 1, and b is 2, 3 or 4.
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Page/Page column 4-5
(2009/01/24)
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- Reaction of Si with HCl to form chlorosilanes time dependent nature and reaction model
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We propose a chemical vapor deposition (CVD) process with closed gas recycling for making low-cost, crystalline silicon thin films for solar cells, which connects chlorosilane synthesis from Si and HCl with Si thin-film growth by CVD from chlorosilanes. In this work we studied the formation of chlorosilanes by the reaction of Si with HCl at temperatures ranging from 623 to 723 K. The reaction rate is time dependent, and many pores are formed on the surface of particles after reaction. These pores are active sites for chemical reactions, and the reaction rates increase with increasing pore area. The rate can be correlated with the conversion ratio of Si, and the temporal evolution of the reaction rate can be explained by a reaction model called the shrinking-core model with growing pores. By using this model, we estimated the reaction rates per unit area of activated surfaces and converted them into a rate equation that can be used for the reactor design. The incubation time of the reaction can be shortened by pretreating the Si particles in a fluidized bed, which probably creates defects in the native oxide layers on the particles, which in turn become reactive sites.
- Noda, Suguru,Tanabe, Katsuaki,Yahiro, Takashi,Osawa, Toshio,Komiyama, Hiroshi
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p. C399-C404
(2008/10/09)
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- Method for preparing a contact mass
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A method of preparing a contact mass is provided comprising reacting silicon and a cuprous chloride to form a concentrated, catalytic contact mass. Furthermore, a method for making an alkylhalosilane using the aforementioned contact mass is provided compr
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- Reactivity of intermetallic compounds: A solid state approach to direct reactions of silicon
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The present work is focused on a new approach to describe, quantify, and compare the reactivity of various transition metal silicide phases toward hydrogen chloride. Thermodynamic and kinetic parameters are obtained from isothermal calorimetric studies of these reactions. The reactivity of the silicide phases is discussed in terms of reaction start temperatures, rate constants, and apparent activation energies. Negative apparent activation energies are observed at low temperatures and are attributed to an initial stage of reaction where chlorine is chemisorbed and then incorporated into the silicide lattice near the surface. At a later time, a chlorine-containing reaction layer is formed having a composition and reactivity remarkably different from that of the bulk phase. On the basis of solid-state investigations, a diffusion model of the microscopic structure of these layers is presented, where a displacement of nickel atoms occurs followed by the occupation of nickel sites by chlorine. A model is suggested in which the electron level of the reaction layer is adjusted by the chlorine content of this layer, resulting in a electronic stabilization of silylenoide species at the surface. The model is applied to explain product distribution in the induction period during the direct reaction of silicon and methyl chloride.
- Acker, Joì?rg,Bohmhammel, Klaus
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p. 5105 - 5117
(2007/10/03)
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- Unprecedented oxidative chlorosilylation addition reactions to a diarylgermylene and -stannylene
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Treatment of MAr2 [Ar- = C?6H3(NMe2)2-2,6 and M = Ge (1) or Sn (2)] with silicon tetrachloride, or 2 with SiCl3Me, under mild conditions in diethyl ether afforded in good yields the appropriate silylgermane or -stannane M(Ar)2Cl(SiCl3) [M = Ge (3), Sn (4)] and Sn(Ar)2Cl(SiCl2Me) (5). The X-ray structures of 3 and 5 show that while in 3 there is no very close Ge?N contact (the molecule having germanium in a distorted tetrahedral environment), 5 has a distorted pyramidal structure around the tin atom, with a Cl and a N atom in apical sites. Solutions of 3 and 4 in C6D6 showed the former to be stable, while the latter slowly decomposed, yielding β-tin and Sn(Ar)2Cl2 among the products; solutions of 5 showed the presence of the equilibrium 2 + SiCl3Me ? 5, and in CDCl3the mixture afforded Sn(Ar)2Cl(CDCl2).
- Drost, Christian,Hitchcock, Peter B.,Lappert, Michael F.
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p. 2095 - 2100
(2008/10/08)
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- Methods of making polymeric arrays
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Methods are provided for making arrays of distinct polymers covalently bonded to the surface of the a solid support. In the subject methods, at least two distinct polymers, e.g. nucleic acids, are contacted with the surface of a solid support under condit
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- Pyrolysis of trichlorosilane in the presence of chloroform
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The pyrolysis of trichlorosilane in the presence of different amounts of chloroform and the copyrolysis of HSiCl3 with buta-1,3-diene in the presence of 1 mol.% chloroform were studied. The enthalpies of formation of products resulting from the pyrolysis of HSiCl3 in the presence of chloroform were calculated by the quantum chemical method. Based on the thermochemical data as well as data from GLC and mass spectrometry, it was concluded from the condensate composition that introduction of chloroform into the zone of pyrolysis of HSiCl3 favors generation of silylenes.
- Krasnova,Abramova,Alekseev,Chernyshev
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p. 1960 - 1963
(2007/10/03)
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- The detection of O=SiCl2 as an intermediate during the combustion process of SiCl4 with O2
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During the technical important combustion of SiCl4 with oxygen [SiCl4(g) + O2(g) = SiO2(s) + 2·Cl2(g)] many intermediates have been detected in the past. However, the presence of the primary species O=SiCl2 has been discussed controversially until today. With the help of matrix isolation technique we have now been successful to monitor O=SiCl2 via its IR spectrum. With the help of quantum chemical calculations the thermodynamic data have been calculated first. On this basis it was possible to find the optimal conditions to trap OSiCl2 from the high-temperature equilibrium. Furthermore it could be shown via IR spectroscopy and quantum chemical calculations, that the radical OSiCl does not play a significant role within this combustion process.
- Junker,Wilkening,Binnewies,Schnockel
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p. 1531 - 1535
(2007/10/03)
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- Gas-Phase Synthesis of Alkylchlorogermanes
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The major product of the hexachlorodisilane-initiated reaction of MeCl with GeCl4 at 500 and 550°C is MeGeCl3. The reactions of AlkSiCl3 (Alk=Me, Et) with GeCl4 at 550 50°C not produce (Alk=Me) or produce (Alk=Et) AlkGeCl3; a mechanism of formation of the latter is proposed.
- Chernyshev, E. A.,Komalenkova, N. G.,Yakovleva, G. N.,Bykovchenko, V. G.,Khromykh, N. N.,et al.
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- Intermediates and products of the hexachlorodisilane cleavage of group 14 element phosphanes and amines - Molecular structure of di-tert- butyl(trichlorosilyl)phosphane in the gas phase determined by electron diffraction and ab Initio calculations
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Reactions of dialkyl(trimethylsilyl)phosphanes RR'PSiMe3 (1: R, R' = tBu; 3: R, R' = iPr; 5: R = iPr, R' = tBu) with Si2Cl6 provide stable trichlorosilylphosphanes RR'PSiCl3 (2, 4, 6); the reactions of silyl- and stannylamines of iPr2NMMe3 (M = Si: 11; M = Sn: 12) with Si2Cl6, however, provide the stable pentachlorodisilanylamine iPr2NSi2Cl5 (13). Heating of 1 with the technical mixture Me2(Cl)SiSiCl2Me/(MeCl2Si)2 yields the stable silylphosphane tBu2PSiMe2Cl (8) and the disilanylphosphane tBu2PSi(Me)(Cl)Si(Me)Cl2 (9). Methylation of 9 with MeLi gave tBu2PSi2Me5 10, which was isolated in a pure state. Reactions of tBu(iPr)PSiMe3 (5) and of organometal phosphanes tBu(iPr)PMR3 (14: M = Ge, R = Me; 17a-c: M = Sn; R = Me, Et, nBu) with Si2Cl6 were monitored by 31P, 29Si, and 119Sn NMR. - In the first step of these reactions, new tBu(iPr)PSi2Cl5 (7) is formed. 7 is accompanied by increasing amounts of tBu(iPr)PSiCl3 (6) and Me3GeSiCl3 (15)/(Me3Ge)2Si(SiCl3)2 (16) or traces of compounds R3SnSiCl3 (19a-c) that decompose providing (R3Sn)2Si(SiCl3)2 (18a-c) and nBu3SnSi(SiCl3)3 (20c). Subsequently, compounds 19a-c decompose providing increasing amounts of 18a-c. Stannylphosphane 17b is also cleaved by SiCl4 leading to 6 with liberation of Et3SnCl, whereas 17b is formed from the reaction of 5 with Et3SnCl under liberation of Me3SiCl. The suggestion of an extra stabilisation of P-Si bonds of trichlorosilylphosphanes was subjected to direct evidence through the structure determination of the trichlorosilylphosphane tBu2PSiCl3 (2) in the gas phase by electron diffraction. This crowded molecule has a 'normal' P-Si bond length of 225.0(12) pm; its C1 symmetric conformation with both tBu groups and the SiCl3 group twisted about 17°from the perfectly staggered positions, and with each of the three groups tilted about 6°away from each other, allows to reduce steric strain.
- Du Mont, Wolf-W.,Müller, Lars,Martens, Reiner,Papathomas, Paul M.,Smart, Bruce A.,Robertson, Heather E.,Rankin, David W. H.
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p. 1381 - 1392
(2007/10/03)
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- Preparation of tertiary phosphines
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Tertiary phosphines (I) are prepared by reducing the corresponding phosphine oxides (IIa) or phosphine dihalides (IIb) using silicon or a silicon alloy as reducing agent.
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- Reactions of Tetrachlorogermane with Allyl Chloride and Methallyl Chloride in the Presence of Hexachlorodisilane as an Initiator
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Allyl chloride and methallyl chloride react with tetrachlorogermane in the presence of hexachlorodisilane to give as major products allyltrichlorogermane and allyltrichlorosilane in the former case and (2-methyl-2-propenyl)trichlorogermane and (2-methyl-2-propenyl)trichlorosilane in the latter case. The reaction schemes are proposed and discussed.
- Chernyshev,Komalenkova,Yakovleva,Bykovchenko,Khromykh,Bochkarev
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p. 894 - 897
(2007/10/03)
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- Fully Chlorinated W-Silyl Amides of Titanium and Tungsten -Crystal Structure of Cl3SiNW(Cl3)N(SiCl3)2
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The reaction of hexachlorodisilazanyllithium (Cl3Si)2NLi (1), with TiCLi leads selectively to the novel fully chlorinated amides (Cl3Si)2NTiCl3 (2) or [(Cl3Si)2NJ2TiCl
- Schwarze, Bernd,Milius, Wolfgang,Schnick, Wolfgang
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p. 701 - 704
(2007/10/03)
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- Direct synthesis of tris(chlorosilyl)methanes containing Si-H bonds
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Direct reaction of elemental silicon with a mixture of chloroform and hydrogen chloride has been studied in the presence of a copper catalyst using a stirred reactor equipped with a spiral band agitator at various temperatures from 280 to 340 °C. Tris(chlorosilyl)methanes 1a-e with Si-H bonds were obtained as the major products along with byproducts of bis(chlorosilyl)methanes, derived from the reaction of silicon with methylene chloride formed by the decomposition of chloroform, and trichlorosilane and tetrachlorosilane produced from the reaction of elemental silicon with hydrogen chloride. The decomposition of chloroform was suppressed and the production of polymeric carbosilanes reduced by adding hydrogen chloride to chloroform. The deactivation problem of elemental silicon due to the decomposition of chloroform and polycarbosilanes was eliminated. Cadmium was a good promoter for the reaction, while zinc was found to be an inhibitor for this particular reaction.
- Han, Joon Soo,Yeon, Seung Ho,Yoo, Bok Ryul,Jung, Il Nam
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- Gas-Phase Reaction of Hexachlorodisilane with Acetone
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Gas-phase reaction between hexachlorodisilane and acetone was studied at 520-560°C. Hexachlorodisiloxane, 1-allyl-1,1,3,3,3-pentachlorodisiloxane, 1,1,3,3,3-pentachloro-1-vinyldisiloxane, and 1,1,3,3,3-pentachloro-1-vinyloxydisiloxane were found to be major reaction products, and a mechanism of their formation was proposed.
- Chernyshev,Komalenkova,Kapitova,Bykovchenko,Khromykh,Bochkarev
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p. 753 - 755
(2007/10/03)
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- Gas-phase reactions of hexachlorodisilane with chloroform, carbon tetrachloride, and Di- and tetrachloroethylenes
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Gas-phase reactions of hexachlorodisilane with chloroalkanes (CHCl3 and CCl4) and chloroalkenes (ClCH=CHCl and Cl2C=CCl2) are studied. Dichlorosilylenes generated from Si2Cl6 insert into the C-Cl bonds in chloroalkanes; with chloroalkenes, insertion into the C-Cl bonds occurs along with cyclo-addition to the C=C bonds.
- Chernyshev,Komalenkova,Kapitova,Bykovchenko
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p. 1113 - 1116
(2007/10/03)
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- Gas-Phase Synthesis of Phenyltrichlorogermane by Reaction of Germanium Tterachloride with Chlorobenzene in the Presence of Initiators
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The effect of hexachlorodisilane and trichlorosilane as initiators for synthesis of phenyltrichlorogermane were investigated. The mechanism if the influence of these compounds on the reaction of germanium tetrachloride with chlorobenzene is proposed.
- Chernyshev, E. A.,Komalenkova, N. G.,Yakovleva, G. N.,Bykovchenko, V. G.
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p. 1717 - 1720
(2008/10/08)
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- Process for the production of 2-ethoxy-4,6-dihydroxypyrimidine or its alkali salts
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A process is described for the production of 2-ethoxy-4,6-dihydroxypyrimidine or its alkali salt which is an important intermediate in the field of pharmaceuticals and agrochemicals. This compound can be produced using the process according to the invention in good yields and high purity by reacting an O-ethylisourea salt that is preferably formed as an intermediate from cyanamide or chloroformamidinium salts or free O-ethylisourea with an alcoholate and a malonic acid dialkyl ester or a salt of the malonic acid dialkyl ester in alcohol and, if desired, subsequent acidification.
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- The vapor phase formed by reaction of mixtures of aluminum, gold, and chlorine
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A spectrophotometric study of mixed-metal dimers in vapors formed by reaction of Al, Au, and Cl2 is presented. The absorbance of fully vaporized mixtures as well as the gas phase in equilibrium with Au(s) has been observed at various concentrations of Al2Cl6 and Cl2. While AlAuCl6(g) appears to be the dominant mixed-metal dimer, evidence is found suggesting the presence of molecules containing less chlorine, such as AlAuCl5(g). Assuming both AlAuCl6(g) and AlAuCl5(g) are present, thermodynamic properties and UV-visible absorption spectra are derived.
- Rustad,Gregory
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p. 1774 - 1779
(2008/10/08)
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- Analysis of the pyrolysis products of dimethyldichlorosilane in the chemical vapor deposition of silicon carbide in argon
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A study of the products and reactions occurring during the chemical vapor deposition of silicon carbide from dimethyldichlorosilane in argon is presented. The silicon carbide solid that formed showed the presence of hydrogen and chlorine as impurities, wh
- Cagliostro,Riccitiello,Carswell
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p. 607 - 614
(2008/10/08)
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- Selective and sequential reduction of polyhalosilanes with alkyltin hydrides
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The reactions between alkyltin hydrides and a variety of polyhalo- and mixed halosilanes have been investigated. For SiCl4 and SiCl3H, the reductions proceed in a stepwise manner to yield the monoreduced species as the major products. The reduction of SiBr4 occurs much faster to yield a mixture of SiBr3H and SiH4, or, in the vapor phase, SiBr3H as the sole product. SiF3X (X = Br, Cl) is converted into SiF3H, with no further reduction of SiF3H observed upon addition of a second equivalent of alkyltin hydride. SiF2HX compounds (X = Br, Cl) are obtained from SiF2X2 and are converted into SiF2H2 with excess Me3SnH. Redistribution becomes competitive with reduction in reactions between Me3SnH and SiFBr3, leading to mixtures of SiH4, SiF2H2, and SiF3H. The major products in the reaction between SiCl2Br2 and Me3SnH are SiCl3H and SiH4 (no SiCl2H2 was observed). Several probable intermediates were independently synthesized and allowed to react with Me3SnH. Together with deuterium labeling experiments, these reactions shed light on the mechanisms involved in these systems. In particular, the reactions appear not to proceed via free radicals.
- D'Errico, John J.,Sharp, Kenneth G.
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p. 2177 - 2180
(2008/10/08)
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- Reaction of Magnesium Silicide and Silicon Tetrachloride/Trichlorosilane in Presence of Hydrogen
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The formation of silane (SiH4) has been observed during the reaction of silicon tetrachloride and hydrogen (SiCl4 + H2) with magnesium silicide (Mg2Si) at 400-500 deg C.The silane formed decomposes to give silicon in the vicinity of Mg2Si charge.A mixture of trichlorosilane + H2 reacts with Mg2Si at 250 deg C to afford silane which has been separated and decomposed to high purity silicon.The reaction of SiHCl3 + H2 with Mg2Si gives optimum conversion when SiHCl3:H2 ratio is 1:4 at the reaction temperature of 250 deg C.
- Mulla, I. S.,Choube, A. C.,Dongare, M. K.,Sinha, A. P. B.
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p. 756 - 758
(2007/10/02)
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- Reaction of Silicon Difluoride with Halogens: a Reinvestigation
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Reactions of SiF2 with halogens have been reinvestigated by both co-condensation and gas-phase methods.The co-condensation method yields a number of fluorohalogenosilanes including mono-, di-, and higher silane derivatives.These compounds contain SiF, SiF2, and SiF3 units.The reactivity towards SiF2 decreases from chlorine through bromine to iodine.While chlorine and bromine give rise to a number of fluorohalogenosilanes, iodine yields only the monosilane derivatives.In contrast, the gas-phase reaction do not progress to any appreciable extent.The products have been characterized by mass spectrometry and 19F and 29Si n.m.r. spectroscopy.Many have been identified for the first time.
- Suresh, Bettadapura S.,Thompson, James Charlton
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p. 1123 - 1126
(2007/10/02)
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