Home > Community > What is the best solution to prevent the oxidation of Benzaldehyde...
Upvote

26

Downvote
+ Catalysis
+ Benzoic acids
+ Vacuum systems
+ Benzaldehydes
+ Zeolites
+ Heterogeneous catalysis
+ Asymmetric catalysis
Posted by
Kamal L C

What is the best solution to prevent the oxidation of Benzaldehyde...

Larry Rafey  Follow

Just try to do your reaction under N2 atomosphere

More

Upvote

VOTE

Downvote
Axiel Mohamad  Follow

Thank you so much for taking time to write the answers. 
Hi Talaat I. El-Emary, In the first method you suggested, if I understand correctly, Sodium carbonate is used to convert benzoic acid to sodium benzoate which is then removed by washing with water. The magnesium sulfate is used to get rid of the residual water.I didn't quite get the reason for adding hydroquinone or catechol? Also, I would be adding a lot of things to get rid of a single compound, I hope it doesn't defeat my purpose. 
Hi Ashis Ranjan Bandyopadhyay,  thanks for the suggestion. I was wondering if I could get benzaldehyde in a septum sealed bottle so that I wouldn't have to worry about this contamination.

More

Upvote

VOTE

Downvote
David L. Avery  Follow

Hi Koushik Ponnuru 
The addtion of hydroquinone or catechol is to prevent air oxidation of benzaldehyde to benzoic acid and by this way you can kept benzaldehde for a long time in a well closed bottle without oxidation to benzoic acid.

More

Upvote

VOTE

Downvote
Don Welty  Follow

Thank you for correcting my mistake.
I  wonder whether benzaldehyde can give rise to oligomerisation as in case of formaldehyde ?

More

Upvote

VOTE

Downvote
Bunny97  Follow

I presume, you are trying to join one of the methyl carbons of acetone with the carbonyl carbon of benzaldehyde. Such reactions are nicely carried out by using alcoholic KOH , added to the acetone and then you add your benzaldehyde to the mixture. The protocol is available in published literature.
When ever benzaldehyde is required in synthesis, it should be used fresh ( not an old sample) and in freshly distilled form.

More

Upvote

VOTE

Downvote
Dami Victor  Follow

Please refer to my earlier comment.
In one of the following publications you will find that the reaction of 3-pentanone with propionaldehyde using alcoholic KOH, is reported, and there the reference for the original work is included.
1. Canadian Journal of Chemistry, 65, 487 (1987).
2. Canadian Journal of Chemistry, 64, 1553. (1986).
Let me now come to the point you have posed. I have no knowledge about the commercial  availability of benzaldehyde in a septum sealed bottle. You may check the catalogues of leading manufacturers / suppliers of the world to get information. Alternatively, you may write to them for help as well.
Please note that oxidation is not the only reaction that can take place during storage of benzaldehyde. This chemical can also give rise to aldol condensation with self. Please check with an old bottle of this chemical, you are likely to find a relatively viscous material inside.

More

Upvote

VOTE

Downvote
Dan Chadwick  Follow

Probably preserving benzaldehyde at nitrogen gas atmosphere and use of Dehydration agent and dissolved oxygen removing agent some thing like sodium sulfite.    We have to take care of formation of sodium benzoate in this case.  These are all the possible ways.

More

Upvote

VOTE

Downvote
Alan Koenigsberg  Follow

The addtion of hydroquinone and/ or catechol is to prevent air oxidation of benzaldehyde to benzoic acid.

More

Upvote

VOTE

Downvote
Cristopher Milean  Follow

Hi Koushik Ponnuru
Benzaldehyde, suitable for synthesis, is purified in the following way. A 60-g. (58-ml.) sample is washed with two 20-ml. portions of 10% sodium carbonate and then with water. It is then dried over 5–10 g. of anhydrous magnesium sulfate. A few small crystals of hydroquinone or catechol are added with the drying agent. The dry benzaldehyde is decanted through a cotton plug into a Claisen flask; it is distilled under reduced pressure, preferably below 30 mm.

More

Upvote

VOTE

Downvote
Colin Banks  Follow


Prevent the oxidation of Benzaldehyde to Benzoic acid is to keep benzaldehyde at low temperature as possible & do not expose it to air.Keep it under nitrogen atmosphere.


More

Upvote

VOTE

Downvote
Allan Nicholas  Follow

Hi Ashis Ranjan Bandyopadhyay, I know for a fact that Benzaldehyde cannot undergo self-condensation as it doesn't have any alpha Hydrogens. But thanks for the references, I will check them out.

More

Upvote

VOTE

Downvote