Acetone preparation from 2-propanol

[borodin]

HI!

 

Could you help me to find information about acetone preparation from 2-propanol ? I have to do this preparation at college and the only information i’ve found isn't enough.

 

The procedure indicates that the 2-propanol is oxidated by hypochlorous acid (HClO). The source of HClO is the reaction of sodium hypochlorite with acétic acid.

 

I need to explain all the reactions, the whats and the whys, and i can't find it anywhere.

 

I've digitalized the procedure if you want to check. http://rapidshare.com/files/77089369/acetone_preparation_from_2-propanol_.pdf.html

 

Thank you!

Best regards!

[borodin]

Hi again!

 

I've found the reactions, but now i've another problem. I can't find the products (destiled and non destiled) of the two destilations (simple and fractionated). Can you help? Sorry be boring!

 

[Fable]

Sorry, i do not really understand what do you need. Could you please be a little more specific. you cant find it the soultion? or what? the salt (NaCl) is disolved in the water (h2o), an so you have an aqueous solution of acetone, salt and water. Please be more specific. i'd really like to help.

[Testo]

Okay if you have carried out the reaction and distilled it you should have found that acetone (product) boils at around 60C and propan-2-ol (any unreacted starting material) at around 85C. So the first collection should contain the product. You wont have any salt in there arter the distillation, but u may have some water, thats why you need to dry it. Acetone has a distinct smell from propan-2-ol, thats the easiest way of knowing which is which.

[John Cuthber]

Borodin, is it a reaction mechanism you are looking for?

[borodin]

Thank you all! The apresentation of the report was last friday, the day of you firts reply.

 

The mechanism of the reaction that i've found and used was:

 

C4H8O (aq) + NaOCl (aq) -> CH3(CO)CH3 (aq) + NaCl (aq) + H2O (l)

 

 

Represented by the intermediate reactions:

 

NaClO (l) ↔ Na+ (aq) + ClO- (aq)

 

 

ClO- (aq) + CH3COOH (l) → HClO (aq) + H3COO (aq)

 

 

C4H8O (aq) + HClO (aq) → CH3(CO)CH3 (aq) + HCl (aq) + H2O (l)

 

 

Elimination of sodium hypochlorite:

 

Na2S2O3 (aq) + H2O (aq) ↔ 2NaHSO3(aq)

HSO3- (aq) + H2O (l) → SO42- (aq) + 3H+(aq) + 2e-

2HClO (aq) + 2H+ + 2e- → Cl2 (aq) + 2H2O (l)

 

 

Testo,

thanks! I've a doubt: The last destilation is to remove the water, right? why the acetone was dried with sodium carbonate and then destilated (simple), and not the inverse process? Sodium carbonate don't remove only small portions of water?

 

Thanks anyway!

 

Best regards!

[Testo]

Well borodin, the double distillation is slightly confusing but I don't think the last distillation is to remove water as there shouldn't be much in a fraction collected at 57-75C, thats why it's dreid over Sodium carbonate. I think it's just to purify the acetone again because the fraction collected wasn't very pure, that's the only reason i would do two distillations - if the first one failed to give me my product! Unusual to see that in a procedure however...