- 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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- Preparation method of phenyl chlorosilane
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The invention discloses a preparation method of phenyl chlorosilane. The preparation method comprises the following steps: (1) adding silicon powder, a copper catalyst and a sodium-containing compoundinto a reactor; (2) introducing a silicon-copper contact body modifier to pre-treat a silicon-copper contact body at a temperature of 300-500 DEG C; (3) mixing the pretreated silicon-copper contact body with a Cu-CuO-Cu2O-CuCl quaternary copper powder catalyst, and adding the mixture into the reactor; and (4) introducing chlorobenzene, controlling the reaction temperature to be 400-700 DEG C, andcarrying out a reaction to prepare phenyl chlorosilane monomers. According to the method, the use amount of the copper catalyst is low, the conversion rate of chlorobenzene is high, selectivity of phenyl chlorosilane is good, and the yield of diphenyl dichlorosilane with relatively high economic value is high in the product, so that economical efficiency of the phenyl chlorosilane prepared by thedirect method is improved.
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Paragraph 0053; 0054
(2019/07/04)
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- Electrochemical properties of arylsilanes
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In the past, the electrochemical properties of organosilicon compounds were investigated for both fundamental reasons and synthesis purposes. Little is, however, known about the electrochemical behaviour of hydrogen-bearing arylsilanes. Here, we throw light on the electrochemical properties of 11 arylsilanes compounds, 2 of them synthesized for the first time. The oxidation potentials are found to depend on both the nature and number of the aryl groups. Based on these findings it was possible to establish some variation trends that match the expected structure–property correlations. Furthermore, we present first insights into the electrochemical reaction kinetics behind and identify several soluble electrochemical oxidation products.
- Biedermann, Judith,Wilkening, H. Martin R.,Uhlig, Frank,Hanzu, Ilie
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- A kind of preparation method of the midbody of entecavir, and intermediate
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The invention discloses Entecavir intermediates and a preparation method thereof. The preparation method of an Entecavir intermediate represented by a formula IV or IV' shown in descriptions comprises the following step of enabling a compound V to be subjected to amino protecting group and hydroxyl protecting group removal reaction in the presence of protonic acid in a solvent. The preparation method disclosed by the invention has the advantages that raw materials are cheap and are easily obtained, reaction conditions are mild, side reactions are few, the yield is high, the pollution to the environment is little, and the intermediates are easily purified and separated, so that the preparation method is applicable to industrial production.
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Paragraph 0386 - 0391; 0400; 0401
(2017/08/02)
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- Entecavir intermediate and its preparation method
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The invention discloses an entecavir intermediate and a preparation method thereof. A provided preparation method for an entecavir intermediate compound 10 comprises the following steps: performing reducing reaction on an ester compound 11 in an organic solvent under the effect of a reducing agent, so as to obtain the compound 10. A provided preparation method for an entecavir intermediate compound 11 comprises the following steps: reacting a compound 12 with a hydroxyl protection reagent in an organic solvent in the presence of an acid to add a hydroxyl protection group, so as to obtain the compound 11. The preparation methods are cheap and easily available in raw materials, mild in reaction conditions, relatively high in product yield, good in atom economy, friendly to environment, and suitable for industrialized production.
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Paragraph 0380-0383; 0393; 0394; 0396
(2017/12/28)
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- Entecavir intermediate and its preparation method
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The invention discloses an entecavir intermediate and a preparation method thereof. A provided preparation method for an entecavir intermediate compound 8 comprises the following steps: performing hydroxyl protection group removal reaction on a compound 9 in a solvent under an acidic condition, so as to obtain the compound 8. A provided preparation method for an entecavir intermediate compound 9 comprises the following steps: performing hydroxyl protection group adding reaction on a compound 10 in an aprotic organic solvent under an alkali condition, so as to obtain the compound 9. The preparation methods are cheap and easily available in raw materials, mild in reaction conditions, relatively high in product yield, good in atom economy, friendly to environment, and suitable for industrialized production.
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Paragraph 0377-0382; 0391; 0392; 0393; 0394; 0395; 0396
(2017/12/28)
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- Reaction of chloro(ethyl)silanes with chloro(phenyl)silanes in the presence of aluminum chloride. Synthesis of chloro(ethyl)(phenyl)silanes
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Abstract Substituent exchange at the silicon atom between chloro(phenyl)silanes (PhSiCl3, MePhSiCl2, Ph2SiCl2) and chloro(ethyl)silanes (EtSiCl3, Et2SiCl2, Et3SiCl, Et4Si) in the presence of aluminum chloride has been studied. The examined compounds, except for PhSiCl3 and Et4Si, react fairly readily to give chloro(ethyl)-(phenyl)silanes in up to 48-52% yield. A probable mechanism has been proposed.
- Lakhtin,Eremeeva,Gordeev,Ushakov,Bykovchenko,Kirilin,Chernyshev
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p. 595 - 599
(2015/05/13)
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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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- 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 4
(2012/12/13)
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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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- Making of contact mass for organohalosilane preparation and preparation of organohalosilanes
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Organohalosilanes are prepared by charging a reactor with a contact mass comprising metallic silicon and a catalyst and feeding an organohalide-containing gas to the reactor. The contact mass is prepared by premixing metallic silicon and a tin compound and heat treating the premix at 300-600° C. in an inert gas atmosphere.
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Page/Page column 5
(2008/06/13)
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- Synthesis of 2-methylidene-1-silacyclohexanes from 2,6-dibromohex-1-ene and polyhalosilanes
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Various 2-methylidene-1-silacyclohexanes were prepared by straightforward syntheses from readily available polychloro- or polyfluorosilanes, magnesium and 2,6-dibromohex-1-ene using Barbier-type conditions or a previously synthesized Grignard reagent. Good yields were obtained considering the low stability of the products in the reaction conditions.
- Díez-González, Silvia,Blanco, Luis
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p. 5531 - 5539
(2007/10/03)
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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 organohalosilanes
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Organohalosilanes are prepared by charging a reactor with a contact mass of metallic silicon and a catalyst and feeding an organohalide-containing gas to the reactor. Tin or a tin compound is used as the catalyst. Then organohalosilanes can be produced quite efficiently at a high reaction rate while maintaining a low T/D ratio and minimizing the deposition of by-products and carbon.
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Page/Page column 6
(2008/06/13)
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- Reaction of germanium tetrachloride with chloro(phenyl)silanes in the presence of aluminum chloride
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The effect of the quantity of aluminum chloride on the direction and depth of reaction of germanium tetrachloride with chloro(phenyl)silanes of the general formula PhnSiCl4-n (n = 1 - 3) was studied to show that radical exchange between germanium and silicon is initiated only if the mixture contains no less than 2.5-5 wt % of aluminum chloride. With trichloro(phenyl)silane, the radical exchange is initiated at 5 wt % of aluminum chloride and results in exclusive formation of trichloro(phenyl)germane. The reactions of GeCl4 with dichlorodiphenylsilane and chlorotriphenylsilane in the presence of 2.5-7.5 wt % of aluminum chloride give dichlorodiphenylgermane as the major product, and at AlCl3 concentrations of above 10 wt % the major product becomes to be trichloro(phenyl)germane.
- Zhun',Sbitneva,Chernyshev
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p. 867 - 869
(2007/10/03)
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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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- Reaction of Hexachlorodisilane with Methallyl Chloride in the Gas Phase. Syntheses of Trichloro(2-niethyl-2-propenyl)silane
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Reaction of methallyl chloride with hexachlorodisilane in the gas phase at 520°C was studied. Trichloro(2-methyl-2-propenyl)silane was shown to be the main reaction product. Among side products of the reaction, (cis-2-butenyl)trichlorosilane, heterocyclic, and aromatic organosilicon compounds were found. A mechanism of the reaction between hexachlorodisilane and methallyl chloride is proposed. It was shown that dichlorosilylenes generated from hexachlorodisilane prefer to react with methallyl chloride which has two reaction centers (C-Cl and C=C) at the C-Cl bond.
- Chernyshev,Komalenkova,Kapitova,Bykovchenko,Khromykh,Bochkarev
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p. 1040 - 1042
(2007/10/03)
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- Reaction of Hexachlorodisilane with Trichloroethynylsilane and 2-Propynyl Chloride in the Gas Phase
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Reaction of acetylenic compounds (trichloroethynylsilane and 2-propynyl chloride) with hexachlorodisilane in the gas phase at 450-520°C was studied. Main products of the reaction were identified, and a mechanism of their formation was proposed. It was shown that of the two reaction centers of 2-propynyl chloride (C=≡C and C-Cl) only the C-Cl bond is involved in reaction with dichlorosilylenes generated from hexachlorodisilane.
- Chernyshev,Komalenkova,Kapitova,Bykovchenko,Khromykh,Bochkarev
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p. 1043 - 1046
(2007/10/03)
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- Gas-Phase Reactions of Hexachlorodisilane with Vinyl Chloride and Allyl Chloride
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Gas-phase reactions of hexachlorodisilane with vinyl chloride and allyl chloride is studied. Dichlorosilylene generated from Si2Cl6 reacts with the above chloroalkenes mainly at the C-Cl bond to form alkenyltrichlorosilanes. The yields of vinyltrichlorosilane and allyltrichlorosilane are 45-63 and 49-81%, respectively. A mechanism of the reactions of Si2Cl6 with vinyl chloride and allyl chloride is proposed.
- Chernyshev,Komalenkova,Kapitova,Bykovchenko,Khromykh,Bochkarev
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p. 1447 - 1450
(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 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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- REACTION OF TRICHLOROSILANE WITH ARYL CHLORIDES IN PRESENCE OF CYCLOPENTADIENE. MECHANISM OF THE FORMATION OF ARYLCHLOROSILANES
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The application of cyclopentadiene is suggested for the determination of the extent to which reactions go by the silylene mechanism, in which the active intermediate species are the diradicals :SiR2.It was shown that the radical-chain reaction of trichlorosilane with aryl chlorides (chlorobenzene, 2-chlorothiophene) and the formation of chloroarylsilanes go mainly by a free-radical mechanism, but also to smaller extent by a silylene mechanism.
- Chernyshev, E. A.,Bykovchenko, V. G.,Kisileva, T. S.
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p. 295 - 296
(2007/10/02)
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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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- SOME PRACTICAL USES OF THE DISILANE RESIDUE FROM THE DIRECT SYNTHESIS OF METHYLCHLOROSILANES
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Some practical uses for the disilane residue from the direct synthesis of methylchlorosilanes have been proposed.This residue can be converted into organochloro-(Me2SiCl2, MeSiCl3, Me3SiCl) or organohydrochloro-monosilanes (HMeSiCl2, HMe2SiCl).These disilanes can also be used for the synthesis of alkyl (haloalkyl, alkenyl, aryl, etc.) methyldichlorosilanes or alkyl (haloalkyl, alkenyl, aryl, etc.) trichlorosilanes.The reductive properties of the Si-Si bond of these species have been utilized (e.g. in the reduction of phosphine oxides into the corresponding phosphines).Polysilanes resulting from the disproportionation of this residue are precursors of polycarbosilanes.
- Calas, Raymond,Dunogues, Jacques,Deleris, Gerard,Duffaut, Norbert
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p. 117 - 130
(2007/10/02)
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- ONE-STEP REGIOSPECIFIC SYNTHESIS OF ALLYLIC SILANES - EXTENSION TO BENZYLSILANES
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Allyltrichlorosilanes are prepared according to a one-step regiospecific process based on the reaction of allyl chlorides with SiCl4 and NiCp2/HMPA (catalyst), in the presence of industrial methylchlorodisilane fraction.Benzyltrihalosilanes are similarly obtained.
- Lefort, Marcel,Simmonet, Christian,Birot, Marc,Deleris, Gerard,Dunogues, Jacques,Calas, Raymond
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p. 1857 - 1860
(2007/10/02)
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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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- Process for the preparation of chlorosilane
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Dichlorosilane and phenyltrichlorosilane are prepared in good yields by reacting trichlorosilane and diphenyldichlorosilane in the presence of aluminium chloride, as catalyst, and a small proportion of a co-catalyst which is selected from hydrochloric acid and alumina and mixtures thereof, isolating the dichlorosilane from the reaction medium as it is formed and isolating the phenyltrichlorosilane obtained at the end of the reaction.
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