Avoiding Carbothermal Reduction: Distillation of Alkoxysilanes from Biogenic, Green, and Sustainable Sources
| Autor: | Joseph C. Furgal, Vera Popova, David Pan, Xingwen Zhang, Richard M. Laine, Phi H. Doan |
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| Rok vydání: | 2015 |
| Předmět: |
Green chemistry
010405 organic chemistry Chemistry Depolymerization General Chemistry General Medicine 010402 general chemistry 01 natural sciences Catalysis Silicate 0104 chemical sciences chemistry.chemical_compound Crystallinity Carbothermic reaction Organic chemistry Ethylene glycol Fumed silica |
| Zdroj: | Angewandte Chemie (International ed. in English). 55(3) |
| ISSN: | 1521-3773 |
| Popis: | 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 Si(met) , 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. |
| Databáze: | OpenAIRE |
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