Dr. Who
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Styrene to Acetophenone
Hey, there mad scientists. I've been looking to make some acetophenone as it's quite useful and fairly non-toxic. I had the idea to oxidize styrene to
acetophenone with KMnO4. The problem is I'm concerned about over oxidation destroying the product. So two questions: Does this look like it would
work? and is KMnO4 the best oxidizer for this?
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Antigua
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Wouldn't you just get benzaldehyde or maybe some styrene oxide formed? How would you get acetophenone when there isn't a methyl to be coupled to the
carbonyl carbon?
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Dr. Who
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Yup. Don't really know how I missed that. Upon further research, I'm pretty sure a Wacker oxidation would do the trick though.
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Benignium
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I know this is not strictly relevant to your question, but in my opinion the most worthwhile apparent method is the dry distillation of calcium
benzoate with a slight excess of calcium acetate. From 1.7 moles of calcium benzoate I managed to produce 0.9 moles of acetophenone which corresponds
to a yield of 52.9%.
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Fery
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Dr. Who - the reaction between double bound and very cold water solution of KMnO4 produces diol (first step is addition of MnO4- to the double bound,
so the molar ratio of reactants is 1:1, then some manganate produced can undergo disproportionation into MnO2 and permanganate). Also take in fact
that a reactant could be very little soluble in water (e.g. your case = good stirring or emulsifier/emulsification required if you want to produce
more than traces of the product). Higher temperature of the reaction and the double bound is split and from the styrene you'll end up with benzoic
acid (when solution of KMnO4 is too much concentrated and reactant soluble in water the temperature of this exothermic reaction rises quickly so you
are unable to sufficiently perform the reaction in cold = sometimes very diluted solution must be used).
Also KMnO4 could be on watched list in some countries and then hard to obtain there.
Why not to buy 600g of acetophenone on ebay for 50 US$ or 120g for 16 US$ ? Is it also on watched list in your country?
https://www.ebay.com/itm/600g-Acetophenone-98-FG/20311778420...
I understand well the beauty of chemistry in comparison with colorless buying and waiting for the delivery of the product.
[Edited on 25-11-2020 by Fery]
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Dr. Who
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I don't believe it's restricted so much as inadvisable to buy a bunch online. I just had a butt load of styrofoam kicking about from my last glassware
shipment so I figured that turning it into styrene then acetophenone would be better than outright buying it. Looking at Beningium's post I'll
probably try that. Benzoic acid isn't super cheap where I live, but it's within the realm of stuff a broke-ass student like me can afford. I might try
and oxidize the styrene with ozone (which is basically free for me) to the benzoic acid I need.
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Fyndium
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I was wondering don't they sell styrene as a glass fiber resin solvent there? I can buy it by the gallon for less than 10€ a liter. Conversion of
polystyrene tends to be very messy and yields are not usually great.
If you need a bargain, I'd suggest checking the reagents section, there are the guys who get you everything. I've bought specialty reagents there
whenever I need some.
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Dr. Who
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I haven't looked into that. I suppose I could, but the "fun" of the project was getting the styrene from polystyrene. I don't really mind the mess
either.
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