- Sustainable Catalytic Synthesis of Diethyl Carbonate
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New sustainable approaches should be developed to overcome equilibrium limitation of dialkyl carbonate synthesis from CO2 and alcohols. Using tetraethyl orthosilicate (TEOS) and CO2 with Zr catalysts, we report the first example of sustainable catalytic synthesis of diethyl carbonate (DEC). The disiloxane byproduct can be reverted to TEOS. Under the same conditions, DEC can be synthesized using a wide range of alkoxysilane substrates by investigating the effects of the number of ethoxy substituent in alkoxysilane substrates, alkyl chain, and unsaturated moiety on the fundamental property of this reaction. Mechanistic insights obtained by kinetic studies, labeling experiments, and spectroscopic investigations reveal that DEC is generated via nucleophilic ethoxylation of a CO2-inserted Zr catalyst and catalyst regeneration by TEOS. The unprecedented transformation offers a new approach toward a cleaner route for DEC synthesis using recyclable alkoxysilane.
- Putro, Wahyu S.,Ikeda, Akira,Shigeyasu, Shinji,Hamura, Satoshi,Matsumoto, Seiji,Lee, Vladimir Ya.,Choi, Jun-Chul,Fukaya, Norihisa
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p. 842 - 846
(2020/12/07)
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- Method for preparing cyanoethyl triethoxysilane
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The invention relates to the field of organic chemical preparation processes, in particular to a method for preparing cyanoethyl triethoxysilane. The method is used to carry out an addition reaction by using a solid supported catalyst, and mainly comprises the following steps:, i.e., firstly, immobilizing tetraethoxysilane on a 4A molecular sieve, so as to obtain more hydroxyl groups thereon by hydrolysis, then immobilizing titanium ions on the 4A molecular sieve, and removing hydrochloric acid produced therein by using a co-catalyst hexamethylphosphoric triamide; carrying out a feed reaction by using a mixture during synthesis, i.e., firstly, putting the catalyst and the co-catalyst together into a reaction still, carrying out the addition reaction on the mixture through the solid supported catalyst, and after the reaction, directly distilling a crude product to obtain 99% or more of a product. The molar yield of the product prepared by the method can reach 94% pr more; and the solid supported catalyst can be reused. Compared with the existing method, the yield of the synthesized product is relatively high, the product quality is relatively stable, and the method has the advantages of low cost, high capacity, fewer by-products, low demand for equipment and the like, and is easy for industrial production.
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Paragraph 0021; 0022
(2017/08/28)
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- Preparation of polyfunctional nitriles by the cyanation of functionalized organozinc halides with p-toluenesulfonyl cyanide
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Various alkyl, alkenyl, akynyl, benzylic, aromatic or heterocyclic organozinc halides bearing functional groups such as an ester, a boronic ester, a cyanide, a halide or a trialkoxysilyl group react under mild conditions with p-toluenesulfonyl cyanide affording polyfunctional nitriles in 69-93% yields.
- Klement, Ingo,Lennick, Klaus,Tucker, Charles E.,Knochel, Paul
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p. 4623 - 4626
(2007/10/02)
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- PREPARATION OF ALKOXYSILANES BY ETHERIFICATION OF CHLOROSILANES WITH REMOVAL OF HYDROGEN CHLORIDE BY VAPOR OF THE BOILING SOLVENT.
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Etherification of chlorosilanes with alcohols is the usual method of obtaining alkoxysilanes. Hydrogen chloride formed as a byproduct must be removed so as to avoid side reactions and increase the yield. The vapor of boiling solvent was used as an agent to remove hydrogen chloride from the reaction zone. Various solvents were tried and their effect on yield was studied. Removal of hydrogen chloride with the vapor of the boiling solvent during etherification of chlorosilanes makes it possible to obtain alkoxysilanes in 80-90% yield as the result of strong suppression of side reactions.
- Belyakova,Pomerantseva,Efimova,Chernyshev
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p. 426 - 427
(2007/10/02)
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- Process for the preparation of N-substituted aminoalkylsilanes
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N-substituted aminoalkylsilanes are obtained via a selective process which comprises reacting a cyanoalkylsilane with a primary or secondary amine in the presence of a heterogeneous hydrogenation catalyst selected from the group consisting of rhodium, platinum and palladium.
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