- Design and synthesis of readily degradable acyloxysilane dendrimers
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Two types of dendrimers with AB2 branching, one with acyloxysilanes at the branching position (V type) and the other at the non-branching position (Y type), were synthesized using hydrosilylation with chlorosilanes followed by heterofunctional condensation with olefin-functional carboxylic acids, and examined as readily degradable template materials. The V type dendrimer was much more susceptible to ligand redistribution with chlorosilanes during preparation, whereas the Y type was less. The acyloxysilane linkages in these dendrimers could be cleaved readily by alcoholysis or hydrolysis on demand, making for suitable templates.
- Downing, Christopher M.,Missaghi, Michael N.,Kung, Mayfair C.,Kung, Harold H.
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- Continuous and batch organomagnesium synthesis of ethyl-substituted silanes from ethylchloride, tetraethoxysilane, and organotrichlorosilane for production of polyethylsiloxane liquids. 2. Continuous one-step synthesis of ethylethoxy- and ethylchlorosilanes
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Development of a continuous one-step manufacturing process for ethylethoxy- and ethylchlorosilanes is described. The methodology of synthesis of ethyl-substituted silanes has been improved. The important factors for the successful synthesis have been determined. Among them are (1) the replacement of some tetraethoxysilane 3 by ethyltrichlorosilane 10, (2) the optimum concentration of 3 and 10, (3) the excess of the granulated magnesium (the supply rate 50-110 g h-1), and, finally, (4) the columnar apparatus with the stirrer, resulting in high yields of di-and triethylsilanes, low duration of synthesis, and high selectivity of Grignard reagent. Continuous one-step synthesis has been assimilated into industry (up to a scale 7-40 kg h-1 of magnesium) for production of oligoethylsiloxanes with low (5-20%) and high content (up to 40%) of the terminal triethylsiloxy groups. The rules for R/D process of the Grignard synthesis are described.
- Klokov, Boris A.
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- PROCESS FOR THE STEPWISE SYNTHESIS OF SILAHYDROCARBONS
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The invention relates to a process for the stepwise synthesis of silahydrocarbons bearing up to four different organyl substituents at the silicon atom, wherein the process includes at least one step a) of producing a bifunctional hydridochlorosilane by a redistribution reaction, selective chlorination of hydridosilanes with an ether/HCI reagent, or by selective chlorination of hydridosilanes with SiCI4, at least one step b) of submitting a bifunctional hydridochloromonosilane to a hydrosilylation reaction, at least one step c) of hydrogenation of a chloromonosilane, and a step d) in which a silahydrocarbon compound is obtained in a hydrosilylation reaction.
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Page/Page column 54; 57
(2021/12/08)
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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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- 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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- A direct method for preparing ethyldichlorosilane and its comparison with known alternative methods
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Various methods, alternative to direct synthesis, for preparing an important commercial organosilicon monomer, ethyldichlorosilane, were studied in detail. The methods, including organomagnesium and organoaluminum procedures, hydrosilylation, and combined methods, were analyzed from the viewpoint of feasibility of laboratory and small-tonnage commercial production, and their advantages and drawbacks were revealed.
- Lebedev,Sheludyakov,Lebedeva,Ovcharuk,Govorov,Kalinina
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p. 629 - 633
(2014/11/08)
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- Continuous and batch organomagnesium synthesis of ethyl-substituted silanes from ethylchloride, tetraethoxysilane, and organotrichlorosilane for production of polyethylsiloxane liquids. 1. Batch one-step synthesis of ethylethoxysilanes and ethylchlorosilanes
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Development of batch one-step manufacturing process for ethylethoxy- and ethylchlorosilanes is desribed. The methodology of synthesis of ethyl-substituted silanes has been improved. The important factors for the successful synthesis have been determined. Among them are the replacement of the part tetraethoxysilane 3 by ethyltrichlorosilane 10, the optimum concentration of 3 and 10 resulting in high yield of triethylsilanes, low duration of synthesis, and high selectivity of Grignard reagent. Batch one-step synthesis has been assimilated into industry (up to a scale 240 kg of magnesium) for production of oligoethylsiloxanes with the high content (>40%) of a terminal triethylsiloxy group. The rules for R/D process of the Grignard synthesis are described.
- Klokov, Boris A.
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- Stepwise organomagnesium synthesis of mixtures of ethyletoxysilanes and ethylchlorosilanes
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Mixture of ethylethoxy- and ethylchlorosilanes was prepared in a toluene solution by successive reaction of magnesium with a mixture of ethyl chloride and tetraethoxysilane and then with a mixture of ethyl chloride and tetrachlorosilane.
- Klokov
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p. 1863 - 1865
(2007/10/03)
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- The synthesis of -substituted dialkyldichlorosilanes and their conversion into polysiloxanes
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Attack of the oxyl (CF3)2NO. (1) on an ethyl group of the silane Et2SiCl2 occurs at both the α- and β-positions relative to silicon (ratio 31:45), whereas with the silane PrnSiMeCl2 attack takes place at the β-position of the propyl group.With the disilane Me3SiCH2SiMe3, the mojor silicon-containing products formed from treatment with oxyl 1 are Me3SiF, (CF3)2NOSiMe3 and Me3SiSiMe3.Speier-catalysed (H2PtCl6) addition of the silane HSiCl2X (X = Me and Cl) to the alkene (CF3)2NOCH2CH=CH2 gives the adducts (CF3)2NOCH2CH2CH2SiCl2X (29, X = Me) and (28, X = Cl)in high yield.The substituted dichlorosilanes (CF3)2NOCH2CH2SiEtCl2 (9), (CF3)2NOCHMeCH2SiMeCl2 (14) and (CF3)2NOCH2CH2CH2SiMeCl2 (29) are converted into corresponding polysiloxanes ("prepolymers" of low molecular weight) by reaction with reagents including water, acid, base and metal oxides; equilibration of the polysiloxane "prepolymer" 38, derived from dichlorosilane 29 by heating with powdered KOH, affords a solid rubbery polysiloxane.
- Ducker, Graham E.,Tipping, Anthony E.
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p. 253 - 262
(2007/10/02)
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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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- PALLADIUM COMPLEXES IN THE HYDROSILYLATION OF ACETYLENE
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The catalytic activities of triphenylphosphine-, trialkylphosphine-, and acetylacetone-palladium complexes in the hydrosilylation of acetylene with trichloro-, alkyldichloro-, triethyl, and triethoxy-silanes were investigated.The yields of the corresponding (triorganylsilyl)ethylenes and 1,2-bis(triorganylsilyl)ethanes (conditions: 70-80 deg C, solvent xylene) depend on the nature of the ligands on the palladium atom and the character of the substituents on the silicon atom in the hydride silane.
- Kopylova, L. I.,Pukhnarevich, V. B.,Voronkov, M. G.
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p. 276 - 278
(2007/10/02)
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- Macrocyclic polyether compounds
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Macrocyclic polyether "crown" compounds of the formula EQU1 WHEREIN T is a C2 -C3 alkylene, A is EQU2 R being H or C1 -C18 alkyl, R2 and R3 being independently C1 -C18 alkyl, C2 -C4 alkenyl, or C6 -C14 aryl; Q and Z are independently 1,2-arylene (or saturated derivatives thereof) or substituted 1,2-arylene (or saturated derivatives thereof); a is 0, 1, 2, or 3; b is an integer from 3 to 20; y is 1 or zero; x1, x2, x3, and x4 are integers independently selected to give a 15-60 atom ring. Such crown compounds are generally useful in the formation of complexes with ionic metal compounds, thus making it possible to use certain chemical reagents in media wherein they are normally insoluble.
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