17622-94-5Relevant articles and documents
Avoiding carbothermal reduction: Distillation of alkoxysilanes from biogenic, green, and sustainable sources
Laine, Richard M.,Furgal, Joseph C.,Doan, Phi,Pan, David,Popova, Vera,Zhang, Xingwen
supporting information, p. 1065 - 1069 (2016/01/20)
The direct depolymerization of SiO2 to distillable alkoxysilanes has been explored repeatedly without success for 85 years as an alternative to carbothermal reduction (1900 °C) to Simet, followed by treatment with ROH. We report herein the base-catalyzed depolymerization of SiO2 with diols to form distillable spirocyclic alkoxysilanes and Si(OEt)4. Thus, 2-methyl-2,4-pentanediol, 2,2,4-trimethyl-1,3-pentanediol, or ethylene glycol (EGH2) react with silica sources, such as rice hull ash, in the presence of NaOH (10 %) to form H2O and distillable spirocyclic alkoxysilanes [bis(2-methyl-2,4-pentanediolato) silicate, bis(2,2,4-trimethyl-1,3-pentanediolato) silicate or Si(eg)2 polymer with 5-98 % conversion, as governed by surface area/crystallinity. Si(eg)2 or bis(2-methyl-2,4-pentanediolato) silicate reacted with EtOH and catalytic acid to give Si(OEt)4 in 60 % yield, thus providing inexpensive routes to high-purity precipitated or fumed silica and compounds with single Si-C bonds. No detours: The base-catalyzed depolymerization of SiO2 from different sources with diols led directly to distillable alkoxysilanes, including spirocyclic compounds, thus providing inexpensive routes to high-purity silica and compounds with single Si-C bonds (see scheme): The alkoxysilanes could be converted either into Si(OEt)4 by treatment with EtOH and a catalytic amount of acid or into high-purity precipitated (ppt) or fumed silica.
TRANSESTERIFICATION OF TETRAETHOXYSILANE WITH BIFUNCTIONAL ALCOHOLS IN PRESENCE OF NUCLEOPHILIC CATALYSTS
Kopylov, V. M.,Shapatin, A. S.,Gracheva, O. D.,Tandura, S. N.,Prikhod'ko, P. L.
, p. 2086 - 2088 (2007/10/02)
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