Orthosilicic acid Ester

I am trying to find out possibility of synthesis Orthosilicic acid Ester(especially Tetraethyl orthosilicate) from Tetra alkoxy silane(especially from Tetraacetoxy silane).

I even searched this reaction on Reaxys but found confusing result with unreachable references!.

According to stoichiometry each mole of Tetraacetoxy silane need 8 mole of anhydrous EtOH and lead to one mole Tetraethyl orthosilicate and 4 mole ethyl acetate but i think Hydroxyl part of EtOH play important rule for make me doubtful to this reaction!.

I think in this reaction 4 mole of water also produced that Orthosilicic acid ester react with it and maybe polysiloxane formed.

Someone has experience or suggestion?


Some of references that reaxys found:

Žurnal obŝej himii Dolgow et al. yr:1957 vol:27 pg:921
Doklady Akademii nauk SSSR Andrianow et al. yr:1954 vol:94 pg:697
Žurnal obŝej himii Dolgow et al. yr:1957 vol:27 pg:1593
Chem.Abstr., 1955, p. 6087

PS: I have access to Triacetoxymethyl silane(Interesting alkaloxy silane)and probably similar result possible for it and i can try it !.


[Edited on 1-12-2021 by Waffles SS]

Quote: Originally posted by Fery

Waffles SS https://en.wikipedia.org/wiki/Tetraethyl_orthosilicate You can prepare it from SiCl4 + 4 C2H5OH Are you going to prepare aerogel? SiCl4 if you are unable to buy could by synthesized from Si + 2 Cl2 or from SiC2 or ferrosilicium. SiCl4 has quite low boiling point and is very sensitive to air moisture.

Quote: Originally posted by j_sum1

https://www.youtube.com/watch?v=wU77anzCzxg procedure for SiCl4 I don't remember it well except that it seemed within the realms of reasonable doableness.

Quote: Originally posted by Fery

Let us know results of your experiments with the acetate ester of orthosilicic acid. I'm afraid the reaction with ethanol would produce ethyl acetate + SiH4. But I'm not expert in Si chemistry. Mg2Si if works would be perhaps the easiest way to go in home lab. But I'm again afraid that the reaction Mg2Si + alcohol would produce SiH4 + Mg alkoxide. But I'm not expert in Si chemistry. Perhaps at first it will require conversion to SiCl4 too? It would be gorgeous to have here in the forum some working experiments with Si organic compounds. j_sum1 posted here a link to a youtube video of SiCl4 preparation: Quote: Originally posted by j_sum1   https://www.youtube.com/watch?v=wU77anzCzxg procedure for SiCl4 I don't remember it well except that it seemed within the realms of reasonable doableness.

Quote: Originally posted by Waffles SS

I am trying to find out possibility of synthesis Orthosilicic acid Ester(especially Tetraethyl orthosilicate) from Tetra alkoxy silane(especially from Tetraacetoxy silane). I even searched this reaction on Reaxys but found confusing result with unreachable references!. According to stoichiometry each mole of Tetraacetoxy silane need 8 mole of anhydrous EtOH and lead to one mole Tetraethyl orthosilicate and 4 mole ethyl acetate but i think Hydroxyl part of EtOH play important rule for make me doubtful to this reaction!. I think in this reaction 4 mole of water also produced that Orthosilicic acid ester react with it and maybe polysiloxane formed. Someone has experience or suggestion? Some of references that reaxys found: Žurnal obŝej himii Dolgow et al. yr:1957 vol:27 pg:921 Doklady Akademii nauk SSSR Andrianow et al. yr:1954 vol:94 pg:697 Žurnal obŝej himii Dolgow et al. yr:1957 vol:27 pg:1593 Chem.Abstr., 1955, p. 6087 PS: I have access to Triacetoxymethyl silane(Interesting alkaloxy silane)and probably similar result possible for it and i can try it !. [Edited on 1-12-2021 by Waffles SS]

Quote: Originally posted by njl

I think you mean acyloxysilane not alkaloxy.

Hi njl you are right, 4 oxygens missing, my fault . As Waffles SS wrote, there should be ethyl acetate produced which has very similar b.p. to ethanol. Mixture of ethanol (b.p. 78,37 C) + ethyl acetate (b.p. 77,1 C) even forms an azeotrope with much lower b.p. 71,8 °C.