Rhodium:
>I don't know why it doesn't work, but it can be worked around by using "synthetic equivalents" to formic acid, such as dichloromethyl methyl ether, which together with a lewis acis such as SnCl4 or TiCl4 will formylate aromatic compounds.
Okay. But does that mean it still works like a Friedel-Crafts reaction? Can all FC catalysts be used, including such as FeCl3?
Aurelius:
>formic acid decomposes too easily
What does it decompose into? If it decomposes into carbon monoxide, wouldn't it work as a type of Gattermann-Koch reaction which would just as well result in the benzaldehyde?
Lugh:
>According to Calloway's article on the Friedel-Crafts Synthesis in Organic Reactions, formyl groups are introduced by formic acid, hydrogen cyanide and hydrogen chloride (the Gatterman reaction),
So formic acid works fine in that reaction? What is the role of the HCN in the reaction? Do you think some other substance could be used in its place?
>and carbon monoxide and hydrogen chloride (the Gatterman-Koch reaction).
Yes, I have been reading a little in some patents using this reaction. The materials are so available that it is appealing at first glance. CO can be made by heating CaCO3 and zinc to 700-750 deg C or by dehydrating formic acid with sulfuric acid.
The addition of cupric chloride apparently allows the reaction to take place at atmospheric pressure (because the CuCl helps the CO dissolve in water??), but in the industry, the reaction is apparently usually carried out under increased pressure, which I don't know how one deals with in a "kitchen lab" type of arrangement available to most people.
>See Ind Eng Chem 26 1317 (1934) for an article by Groggins about using formic acid directly
I will try to get the library to get it, but can you tell a little more about the conditions under which the reaction takes place? Do they use a catalyst?
Thank you.