- NOUVELLES UTILISATIONS DU TETRAMETHYLSILANE COMME AGENT DE METHYLATION DES CHLOROSILANES; VALORISATION DU METHYLTRICHLOROSILANE
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In the presence of catalytic amounts of AlCl3, the chlorosilanes MeSiCl3, ClMe2SiCH2Cl and PhSiCl3 convert Me4Si into Me3SiCl.In the first case, at 130 deg C, two by-products from the industrial synthesis of Me2SiCl2 provide the useful Me3SiCl as the unique product with a 44percent conversion ratio from Me4Si.From ClMe2SiCH2CL, the only products formed are Me3SiCl and Me3SiCH2Cl, which is a useful reagent for organic syntheses (formation ratio: 32percent), if the reaction is performed under atmospheric pressure, but if an autoclave is used EtMe2SiCl (88percent maximal yield) is obtained.
- Bordeau, M.,Djamei, S. M.,Calas, R.,Dunogues, J.
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- B(C6F5)3-Catalyzed Selective Chlorination of Hydrosilanes
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The chlorination of Si?H bonds often requires stoichiometric amounts of metal salts in conjunction with hazardous reagents, such as tin chlorides, Cl2, and CCl4. The catalytic chlorination of silanes often involves the use of expensive transition-metal catalysts. By a new simple, selective, and highly efficient catalytic metal-free method for the chlorination of Si?H bonds, mono-, di-, and trihydrosilanes were selectively chlorinated in the presence of a catalytic amount of B(C6F5)3 or Et2O?B(C6F5)3 and HCl with the release of H2 as a by-product. The hydrides in di- and trihydrosilanes could be selectively chlorinated by HCl in a stepwise manner when Et2O?B(C6F5)3 was used as the catalyst. A mechanism is proposed for these catalytic chlorination reactions on the basis of competition experiments and density functional theory (DFT) calculations.
- Chulsky, Karina,Dobrovetsky, Roman
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- Grignard reaction with chlorosilanes in THF: A kinetic study
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Kinetics of the reactions of phenylmagnesium chloride and bromide and diphenylmagnesium with chlorosilanes were investigated in tetrahydrofurane (THF) and in THF-hydrocarbon mixtures. The reaction in THF is much faster than that in diethyl ether. Assuming coordination of magnesium halides with three molecules of THF, concentrations of all the species involved in Schlenk equilibrium were calculated. In the Grignard reaction, species R2Mg and RMgX react competitively accompanied by additional reaction paths involving electrophilic catalysis by magnesium halide. This conclusion also proved to be valid for the Grignard reaction with a ketone and probably can be expanded to any Grignard reaction. When Schlenk equilibrium is shifted far to the RMgX species, the catalytic pathways are insignificant. Substituents at the silicon center control the rate of the reaction through their inductive and steric effects.
- Tuulmets, Ants,Nguyen, Binh T.,Panov, Dmitri
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- An efficient method to synthesize chlorosilanes from hydrosilanes
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An efficient, highly selective and productive synthesis of chlorosilanes from hydrosilanes is reported. Ceramic spheres were added to chlorination reaction systems and found to greatly increase the efficiency and yields of the reactions. PhSiH2Cl, PhSiHCl2, PhSiCl3, Ph 2SiHCl, Ph2SiCl2, PhMeSiHCl and PhMeSiCl 2 were synthesized from the corresponding hydrosilanes in only a few hours with yields that typically exceeded 90%. This is the first time PhSiCl3, Ph2SiHCl, Ph2SiCl2 and PhMeSiCl2 have been synthesized by this method. The factors that affect the rate of the chlorination reaction were studied. In addition the rate constant, reaction order and apparent activation energy of the chlorination reaction were also determined by kinetics study. The reaction was found to have an induction period.
- Wang, Wenchao,Tan, Yongxia,Xie, Zemin,Zhang, Zhijie
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- CATALYST REGENERATION IN A PROCESS TO MAKE ARYLCHLOROSILANES
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Arylhalosilanes such as phenylmethyldichlorosilane can be prepared via a reaction using a solid catalyst. The method includes a means for catalyst regeneration. The arylhalosilanes can be hydrolyzed to form aryl-functional siloxane polymers or network resins.
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Paragraph 0028-0033
(2020/09/27)
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- Asymmetric Synthesis of Silicon-Stereogenic Silanes by Copper-Catalyzed Desymmetrizing Protoboration of Vinylsilanes
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The catalytic asymmetric creation of silanes with silicon stereocenters is a long-sought but underdeveloped topic, and only a handful of examples have been reported. Moreover, the construction of chiral silanes containing (more than) two stereocenters is a more arduous task and remains unexploited. We herein report an unprecedented copper-catalyzed desymmetrizing protoboration of divinyl-substituted silanes with bis(pinacolato)diboron (B2pin2). This method enables the facile preparation of an array of enantiomerically enriched boronate-substituted organosilanes bearing contiguous silicon and carbon stereocenters with exclusive regioselectivity and generally excellent diastereo- and enantioselectivity.
- Li, Yanfei,Wang, Ying,Xiong, Tao,Zhang, Ge,Zhang, Qian
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supporting information
p. 11927 - 11931
(2020/05/22)
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- Stereo- And regio-selective synthesis of silicon-containing diborylalkenes: via platinum-catalyzed mono-lateral diboration of dialkynylsilanes
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A highly chemoselective platinum-catalyzed mono-lateral diboration of dialkynylsilanes for the construction of silicon-tethered alkynyl diborylalkenes is described, in which tris(4-methoxyphenyl)phosphine was found to be an effective ligand for the cis-addition of diboron agents to the silicon-tethered alkynes, and the chiral ligand (AFSi-Phos)-mediated diboration of dialkynylsilanes resulted in the desymmetric construction of silicon-stereogenic centers with promising enantioselectivity.
- Long, Peng-Wei,Xie, Jia-Le,Yang, Jing-Jing,Lu, Si-Qi,Xu, Zheng,Ye, Fei,Xu, Li-Wen
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supporting information
p. 4188 - 4191
(2020/04/22)
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- METHOD FOR PRODUCING ARYLSILANE COMPOUND CONTAINING HALOSILANE COMPOUND AS RAW MATERIAL
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PROBLEM TO BE SOLVED: To provide a method for producing an arylsilane compound with low production cost. SOLUTION: A method for producing an arylsilane compound includes a reaction step for the cross-coupling reaction of a halosilane compound represented by general formula (A-1), (A-2), or (A-3) and an arylboronic acid pinacol ester in the presence of a nickel catalyst, a Lewis acid catalyst, and an organic base (R independently represent an aromatic hydrocarbon group, a heteroaromatic ring group, or a C1-20 hydrocarbon group; X independently represent a halogeno group or a trifluoromethanesulfonyloxy group). SELECTED DRAWING: None COPYRIGHT: (C)2020,JPOandINPIT
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Paragraph 0080-0084
(2020/03/06)
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- Neutral-Eosin-Y-Photocatalyzed Silane Chlorination Using Dichloromethane
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Chlorosilanes are versatile reagents in organic synthesis and material science. A mild pathway is now reported for the quantitative conversion of hydrosilanes to silyl chlorides under visible-light irradiation using neutral eosin Y as a hydrogen-atom-transfer photocatalyst and dichloromethane as a chlorinating agent. Stepwise chlorination of di- and trihydrosilanes was achieved in a highly selective fashion assisted by continuous-flow micro-tubing reactors. The ability to access silyl radicals using photocatalytic Si?H activation promoted by eosin Y offers new perspectives for the synthesis of valuable silicon reagents in a convenient and green manner.
- Fan, Xuanzi,Xiao, Pin,Jiao, Zeqing,Yang, Tingting,Dai, Xiaojuan,Xu, Wengang,Tan, Jin Da,Cui, Ganglong,Su, Hongmei,Fang, Weihai,Wu, Jie
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supporting information
p. 12580 - 12584
(2019/08/16)
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- METHOD OF PRODUCING ORGANOHALOSILANES
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A method for producing an organohalosilanes comprising reacting an organic compound comprising a halogen-substituted or unsubstituted alkane, a halogen-substituted or unsubstituted alkene, or an aromatic compound and at least one hydridohalosilane of formula RnSiHmX4-m-n, wherein each R is independently C-1 -C-1 4 hydrocarbyl or C-1 -C-1 4 hologen-substituted hydrocarbyl, X is fluoro, chloro, bromo, or iodo, n is 0, 1, or 2, m is 1, 2 or 3, and m+n=1, 2 or 3, in the presence of a heterogeneous catalyst comprising an oxide of one or more of the elements Sc, Y, Ti, Zr, Hf, B, Al, Ga, In, C, Si, Ge, Sn, or Pb, at a temperature greater than 100 °C, and at a pressure of at least 690 kPa, to produce a crude reaction product comprising the organohalosilane.
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Paragraph 0055
(2016/09/22)
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- Preparation of methylphenyldichlorosilane through a catalytic cracking reaction of 1,2-dimethyl-1,1,2,2-tetrachlorodisilane with halobenzene
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Catalytic cracking reaction of 1,2-dimethyl-1,1,2,2-tetrachlorodisilane with a halobenzene (PhCl, PhBr) to prepare methylphenyldichlorosilane has been investigated. Pd(PPh3)4 exhibited the best catalytic activity among the catalysts used. The activity of chlorobenzene was significantly lower than that of bromobenzene. With the latter and toluene as solvent, in the presence of 0.3 mol % Pd(PPh3)4, the conversion of disilane was 100% with a selectivity to MePhSiCl2 of 97.1%.
- Pi, Yong-Rui,Tan, Jun,Liu, Hui,Chen, Jie,Qun, Zhu-You,Zeng, Yan-Bo,Li, Lei
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experimental part
p. 712 - 714
(2012/03/26)
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- Utility of trichloroisocyanuric acid in the efficient chlorination of silicon hydrides
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The potential of trichloroisocyanuric acid (TCCA) as a chlorination agent for efficient conversion of Si-H functional silanes and siloxanes to the corresponding Si-Cl functional moieties was explored. In comparison to methods using other chlorinating agents, TCCA is inexpensive, results in a much faster reaction and produces a high purity product with a conversion that is essentially quantitative. A variety of chloro derivatives of linear and cyclic structures have been synthesized from silicon hydrides using this reagent with impressive yields that typically exceed 90%: PhSiCl3 (97.5%); PhMeSiCl2 (95.5%); Ph3SiCl (97.5%); Vi3SiCl (98.7%); (EtO)3SiCl (99.7%); t-Bu3SiCl (～100%); (MeClSiO)4 (86.5%); (MeClSiO)5 (95%); (MeClSiO)7 (96.5%); Ph(OEt)2SiCl (98%); ClMe2SiOSiMe2Cl (98.6%); ClMe2SiOSiMeClOSiMe2Cl (94.6%); ClMe2Si(OSiMeCl)2OSiMe2C l (92.3%); (Me3SiO)3SiCl (97%); Me3SiOSiClPhOSiMe3 (99%); Me3SiO(SiMeClO)3SiMe3 (95.7%); ClSi(OSiMe3)2OSi(OSiMe3) 2Cl (93.6%). For monohydridosilanes, dichloromethane (CH2Cl2) was a suitable solvent in which nearly quantitative conversion was observed within several minutes following the addition of the silanes to TCCA. For certain cyclic and linear siloxanes, and especially silanes containing multiple hydrogen atoms on the same silicon for which the reaction is sluggish in CH2Cl2, tetrahydrofuran (THF) was the preferred solvent. For a sterically demanding silane that did not undergo chlorination even in THF viz., HSi(OSiMe3)2O-Si(OSiMe3)2H, 1,2-dichloroethane was the best solvent.
- Varaprath, Sudarsanan,Stutts, Debra H.
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p. 1892 - 1897
(2007/10/03)
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- METHOD OF MAKING PHENYL-CONTAINING CHLOROSILANES WITH ALIPHATIC OR CYCLOPARAFFINIC HYDROCARBON SOLVENTS
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Phenylmethyldichlorosilanes and diphenylmethylchlorosilanes are prepared by a Grignard process involving the step of contacting a phenyl Grignard reagent, an ether solvent, a trichlorosilane, and an aliphatic or cycloparaffinic hydrocarbon coupling solvent; in a mole ratio of the ether solvent to the phenyl Grignard reagent is 2 to 5, the mole ratio of the trichlorosilane to the phenyl Grignard reagent is 0.1 to 10, and the mole ratio of the aliphatic or cycloparaffinic hydrocarbon coupling solvent to the phenyl Grignard reagent is 3 to 7. Preferred reactants include phenylmagnesium chloride as the phenyl Grignard reagent; diethyl ether as solvent; n-heptane as the aliphatic hydrocarbon coupling solvent, or cyclohexane as the cycloparaffinic hydrocarbon coupling solvent; and methyltrichlorosilane.
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(2008/06/13)
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- GRIGNARD PROCESSES WITH IMPROVED YIELDS OF DIPHENYLCHLOROSILANES AS PRODUCTS
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A Grignard process for preparing phenyl-containing chlorosilane products, in particular diphenylchlorosilanes, is carried out in three embodiments. In the first embodiment, the reactants of the Grignard process are a phenyl Grignard reagent, an ether solvent, a trichlorosilane, and an aromatic hydrocarbon coupling solvent. In the second embodiment, the reactants of the Grignard process are a phenyl Grignard reagent, an ether solvent, a phenylchlorosilane, and an aromatic hydrocarbon coupling solvent. In the third embodiment, the reactants of the Grignard process are a phenyl Grignard reagent, an ether solvent, a trichlorosilane, a phenylchlorosilane, and an aromatic hydrocarbon coupling solvent. In each embodiment, the reactants are present in a particular mole ratio.
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Page/Page column 8-9
(2008/06/13)
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- GRIGNARD PROCESSES WITH INCREASED CONTENT OF DIPHENYLCHLOROSILANES
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Three improved Grignard processes are used for preparing phenyl-containing chlorosilane products wherein the yield of diphenylchlorosilanes as a product is maximized, while the yield of phenylchlorosilanes as a product is minimized. In one embodiment, the process involves contacting a phenyl Grignard reagent, an ether solvent, an aromatic halogenated coupling solvent and a trichlorosilane. In another embodiment, the process involves contacting a phenyl Grignard reagent, an ether solvent, an aromatic halogenated coupling solvent, a trichlorosilane, and a phenylchlorosilane. In yet another embodiment, the process involves contacting a phenyl Grignard reagent, an ether solvent, an aromatic halogenated coupling solvent, and a phenylchlorosilane. In each embodiment, the reactants are present in particular mole ratios of the components.
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Page/Page column 6-7
(2008/06/13)
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- Process for preparing organosilanes
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The invention relates to a process for preparing organosilanes of the general formula 1 [in-line-formulae]R3Si—R′??(1), [/in-line-formulae] in which hydrosilanes of the general formula 2 [in-line-formulae]R3Si—H ??(2) [/in-line-formulae] are reacted with halohydrocarbons of the general formula 3 [in-line-formulae]R′—X ??(3) [/in-line-formulae] where R are monovalent C1-C18 hydrocarbon radicals, hydrogen or halogen, R′ are monovalent C1-C18 hydrocarbon radicals and X is halogen, in the presence of a free-radical initiator which is selected from alkanes, diazenes and organodisilanes.
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Page/Page column 2
(2008/06/13)
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- PREPARATION OF ORGANOSILICON INTERMEDIATE AND THEIR DERIVATIVES IN A NOVEL GRIGNARD PROCESS
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A one-step process for the preparation of organosilicon intermediates. The organosilicon intermediates comprise a group which includes such intermediates as 1,4-bis(dimethylsilyl)benzene, 1,4-bis(dimethylchlorosilyl)benzene, and their derivatives. The process comprises: combining a dihalobenzene with magnesium metal in a co-solvent mixture of an ether and an organic solvent and reacting them with an organosilicon compound of the general formula, R2bHcSiXd. The resulting mixture is allowed to react to completion. The resulting mixture is passed through a filtration device. The liquid, now free of solid magnesium halide, is subjected to a separation technique to recover the subject organosilicon intermediates and their derivatives.
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- On the mechanism derived from kinetic solvent effects of Grignard reactions with silanes
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In this communication we present the results of initial kinetic studies in which we have established that alkoxysilanes and chlorosilanes react with Grignard reagents in entirely different ways. The Grignard reaction with alkoxysilanes consists of replacement of a donor molecule at the magnesium centre by silane, followed by a subsequent rearrangement of the complex to the products. Chlorosilanes react without solvent molecule replacement.
- Tuulmets, Ants,Sassian, Meeri
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p. 3942 - 3946
(2007/10/03)
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- Redistribution of dichlorosilanes and dihydridosilanes. Synthesis of chloro hydridosilanes
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The redistribution of dichlorosilanes RSi(CH3)Cl2 and dihydridosilanes RSi(CH3)H2, prepared by reduction of the homologues dichlorosilanes, in the presence of a quaternary ammonium salt is presented. The influence of the nature of R (fluoroalkyl chain RFCH2CH2 with RF = CF3, C4F9, C8F17, alkyl chain R = C6H13 or aromatic R = C6H5) and of the temperature on the rate of the reaction is studied. The equilibrium constants and free enthalpies are calculated and discussed taking into account the nature of R. The new products described were characterized from I.R, 1H, 19F and 29Si NMR spectroscopies.
- Benouargha,Boulahia,Boutevin,Caporiccio,Guida-Pietrasanta,Ratsimihety
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- Process for preparing cyclopentadienyl group-containing silicon compound or cyclopentadienyl group-containing germanium compound
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Disclosed is a process for preparing a cyclopentadienyl group-containing silicon compound or a cyclopentadienyl group-containing germanium compound, comprising reacting (i) a lithium, sodium or potassium salt of a cyclopentadiene derivative with (ii) a silicon halide compound or a germanium halide compound in the presence of a cyanide or a thiocyanate. The cyanide or the thiocyanate is preferably a copper salt. According to the process of the invention, a cyclopentadienyl group-containing silicon compound or a cyclopentadienyl group-containing germanium compound, which is very useful for the preparation of a metallocene complex catalyst component, can be prepared in a high yield for a short period of time.
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- REACTIONS OF TELLURIUM(IV) CHLORIDES WITH SOME ORGANOSILICON HYDRIDES
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The reactions of several organosilicon hydrides PhnSiH(4-n), n = 1, 2; R3SiH, R3 = Ph3, Ph2Me, PhMe2, (n-C6H13)3; (p-Me2HSi)2C6H4, with TeCl4 in benzene resulted in the formation of tellurium metal and chlorosilanes in 75-90percent yields.Similar reactions with aryltellurium trichlorides (RTeCl3, R = Ph, p-MeOC6H4, p-EtOC6H4) proceeded in two different ways.On stirring at room temperature for 6-8 h, diaryl ditellurides and chlorosilanes were obtained in 70-95percent yields whereas on refluxing for 6-10 h, tellurium powder and diaryltellurium dichlorides were obtained along withthe chlorosilanes in 80-95percent yields.Diaryltellurium dichlorides (R2TeCl2, R = Ph, p-MeOC6H4) did not react readily with PhSiH3 nor with Ph3SiH.
- Chadha, Raj K.,Drake, John E.,Neo, Mary K. H.
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- OBSERVATIONS AND COMMENTS ON THE THERMAL BEHAVIOR OF 7-SILANORBORNADIENES
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Evidence for a radical mechanism in the termal decomposition of a 7-silanorbornadiene is presented.It is demonstrated that 2-carboxy-7-silanorbornadienes undergo a formal 1,5-migration of silicon to form O-silyl enol ethers.An earlier suggested rearrangement of a 7-silanorbornadiene to a silepin or silanorcardiene is excluded.A recent report of thermal and photochemical epimerization of 7-silanorbornadienes is shown to be incorrect.
- Barton, Thomas J.,Goure, William F.,Witiak, Joanne L.,Wulff, William D.
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- Stabilization of light-sensitive polymers
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4-Siloxy-derivatives of sterically hindered piperidines are good light-stabilizers for organic polymers, especially for polyolefins. The stabilizers are added in an amount of from 0.01 to 5% by weight, preferably 0.02 to 1% by weight based on the polymer. The new compounds are obtainable by O-silylation of the corresponding 4-hydroxypiperidines.
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