Waffles SS
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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]
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Fery
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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.
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Waffles SS
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Thanks,
I know this route and also another possible route but i am interested to find out possiblity and mechanism of mentioned reaction.
Another interesting routes that i found are:
Portland cement route,
Magnesium Silicide route
Silicon disulfide route...
[Edited on 2-12-2021 by Waffles SS]
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Waffles SS
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I found interesting article:
Reaction of Acetoxysilanes with Hydroxy Compounds
V. M. Kopylov, V. V. Kireev, V. V. Ivanov, G. Yu. Astaf’ev, and Yu. V. KozlovChemistry and Technology of
Organoelement CompoundsState Research Center of the Russian Federation, Moscow, Russia
Attachment: Reaction of Acetoxysilanes with Hydroxy Compounds.pdf (42kB)
This file has been downloaded 183 times
It seems this reaction happen with different mechanism !.
[Edited on 2-12-2021 by Waffles SS]
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Fery
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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:
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Waffles SS
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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:
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According to FR961808 :Magnesium silicide react with alcohol and make Orthosilicic acid Ester , Magnesium alkaloxide and hydrogen
SiMg2 + 8 ROH = Si(RO)4 + 2Mg(OR)2 + 4H2
And i think there is no need for SiCl4 route!.
I did some experience on Triacetoxymethyl silane(TAMS).I mix 0.6mole of dry EtOH with 0.1 mole of TAMS, mixture was slightly warmed and sharp odor of
acetic acid and Ethyl acetate released.
According to article of Reaction of Acetoxysilanes with Hydroxy Compounds i should not get Ethyl acetate but i think small amount
produced !(i didnt heat or reflux it any more)
Attachment: FR961808A.pdf (309kB)
This file has been downloaded 184 times
I also upload interesting article about synthesis of Orthosilicic acid ester(Especially Tetraethyl ester) from Portland cement
Attachment: ic00331a021.pdf (691kB)
This file has been downloaded 190 times
[Edited on 2-12-2021 by Waffles SS]
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njl
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Mood: ambivalent
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| 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] |
I think you mean acyloxysilane not alkaloxy.
| Quote: |
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.
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You're missing 4 oxygens there so fear not...
According to the paper linked above this reaction in principle should work just as well as SiCl4. However to continuously remove the formed AcOH
(necessary since there will be an equilibrium in products) you will need to heat the vessel. Problem is your reactant (EtOH) is much more volatile
than that AcOH so you will need to either start with a huge excess of alcohol or add it during the reaction.
Reflux condenser?? I barely know her!
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Waffles SS
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Yes,You are right Acyloxy
Thanks
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Fery
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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.
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