UranylPeroxysulfate - 7-5-2021 at 19:52
Hi,
I need triethyl orthoacetate for future synthesis. I plan to make it by dehydrating acetamide with P4O10 to acetonitrile followed by ethanolysis of
acetonitrile (I based this procedure on the industrial production of trimethyl orthoformate: methanolysis of hydrogen cyanide).
From what I know, the ethanolysis of acetonitrile can be catalyzed by both acid and base. Since orthoesters are extremely water-sensitive, the
acid/base has to be completely water-free.
Here are the methods I came up with:
Acid catalysis:
- Direct ethanolysis with conc. 98% sulfuric acid as a catalyst
- Saturating an ethanol/acetonitrile mixture with anhydrous HCl gas, then reflux to perform the ethanolysis
The problem with acid catalysis is that a stoichiometric excess of acid is required since ammonia is released in the ethanolysis.
Base catalysis:
- Dissolving NaOH or KOH in ethanol, then remove water using molecular sieves. Filter off the molecular sieves, add acetonitrile, then reflux to
perform the ethanolysis (I do not have sodium metal, so I have to go with this route).
- Adding lithium metal (from batteries) to ethanol to form lithium ethoxide. After it completely reacts, add acetonitrile, then reflux to perform the
ethanolysis.
Which method do you think will work the best?
unionised - 8-5-2021 at 07:21
Adding sulphuric acid to acetonitrile is dangerous.
You may provoke the exothermic trimerisation/ polymerisation. (The same, incidentally, is true with HCN).
https://webwiser.nlm.nih.gov/substance?substanceId=392&i...
HCl seems to be acceptable.
This might help.
https://en.wikipedia.org/wiki/Pinner_reaction