[chungfaitao]

Starting from propene, how do you make propionaldehyde in one step?

I guess you can't just oxidize it, because then you will get an OH on the middle and one of the end carbons.

[sjb]

Can you further oxidise diols?

[chungfaitao]

Where's the diol?

[sjb]

Where's the diol?

Here

...
I guess you can't just oxidize it, because then you will get an OH on the middle and one of the end carbons.

[chungfaitao]

OK, I got you. Thanks.

But if I just oxidized the propene, would I definitely get just propanal, or, if the intermediate stage is propanediol, wouldn't I get a carboxyl in both of the places where the OH were?

[sjb]

Depending on the conditions you use, you can stop the oxidative cleavage at the aldehyde stage - see for instance http://www.organic-chemistry.org/synthesis/C2O/aldehydes/oxidationsalkenes.shtm

[chungfaitao]

OK, thanks.

[Schrödinger]

Starting from propene, how do you make propionaldehyde in one step?

If it weren't just one step, I'd go with Hydroboration-oxidation and further oxidation of the subsequent primary alcohol to propanal

[OC pro]

The reaction you are searching for is the so-called "Wacker" oxidation yielding propanal from propene in one single step using Palladium(II) salts. It is also used in the multi-tons production of acetic acid (Monsanto process).

[Schrödinger]

The reaction you are searching for is the so-called "Wacker" oxidation yielding propanal from propene in one single step using Palladium(II) salts. It is also used in the multi-tons production of acetic acid (Monsanto process).

According to this link - http://www.organic-chemistry.org/namedreactions/wacker-tsuji-oxidation.shtm - Wacker oxidation will yield propanone, not propanal.

So, what you're suggesting, is it a modification to the one in the link or the same ?

[chungfaitao]

OK, I think maybe it is supposed to be done in two steps.

Firststly, to get propan-1-ol from propene, and then oxidise the propan-1-ol to propionaldehyde.

But how do you get propan-1-ol from propene? If you hydrate it with water, then you get propan-2-ol.

[Jorriss]

OK, I think maybe it is supposed to be done in two steps.

Firststly, to get propan-1-ol from propene, and then oxidise the propan-1-ol to propionaldehyde.

But how do you get propan-1-ol from propene? If you hydrate it with water, then you get propan-2-ol.

Hydroboration

[Agathiyar]

Hydroboration is the right approach to get the 1-propanol first, especially if you use bulkier boron reagents, you get better selectivity too. There are number of reagents available for converting hydroxy to aldehyde.

[OC pro]

Sorry my mistake...it was too late in the night. Of course Wacker oxidation of propene gives acetone.

[pacifyer]

I think an oxidation of propylene with a catalyst of Au on TiO2, with a mixture of H2 and O2, at high temperature, may do the trick. The idea is to obtain propylene oxide, and then rearrange it to the aldehyde.

The industrial preparation of propionaldehyde is from synthesis gas (from water and hot coal), and ethylene:

CO + H2 + C2H4 ---> CH3CH2CHO