[yoyoils]

Would anybody know just off the top of your head if Propane with a carboxylic acid could produce Propionic acid? The only few things I can find so far is propionaldehyde aerobic oxidation to propionic acid with the presence of cobalt ions,
or would it even be possible somehow to halogenate gaseous propane and + R-C=O-OH(carboxylic acid) for a propionic acid prep?

or is there anyway to make it from acetic acid? im trying to figure out a way to get an extra methyl group to pure acetic acid if possible somehow..

[tezha]

Alkanes by themeselves are fairly unreactive, propane would not react with the carbocylic acids. The easyest way to synthesize propanoic acid would probably be the oxidation of propan-1-ol with something like permanganate or dichromate.

[Guitarmaniac86]

From a theoretical stand point you could react propane with N-bromosuccinimide in an alkyl peroxide, then react that with hydroxide under SN2 conditions, then oxidise it to a propanoic acid with dichromate. However, bromine radicals are very selective and may not lead to the desired product in the initial stages. By that I mean you would need the bromine to attach to C-1, but it would more likely add to C-2 (the second carbon in the chain) because the radical intermediate is more stable in the secondary position.

You would really be better off oxidising 1-propanol with dichromate because alkanes are really not that reactive.

[Nosterius]

Yoyoils,

In the industry, propionic acid is prepared by reacting ethylene with CO and H2 catalyzed by Co, Rh or Ru catalysts, in a process called "hydroformylation". This reaction yields propionaldehyde, which is then oxidized with air as you suggested. This is how large scale manufacturer do.

As for a "on paper" answer, you should consider oxidizing 1-propene as suggested bellow. However, you have to realize that 1- and 2-bromopropane will both yield 1-propene after an E2 reaction (use t-BuOK instead of an hydroxide source to avoid Sn2 reaction taking precedence). You can then wrap this synthesis up with a little bit of your favorite oxidizing agent.