# Phenylacetone (P2P) synthesis from 1-phenyl-2-nitropropene (P2NP) via FeCl3



## William Dampier

*Reagents:*

1-Phenyl-2-nitropropene (P2NP; cas 705-60-2) 1.63 g, 10 mmol;
Powdered iron (Fe) 3 g;
FeCl3 0.6 g;
Hydrochloric acid (HCl 36% aq.) conc. 4 ml;
Toluene 15 ml;
Water 55 ml;
Hydrochloric acid 3N (10.45%) HCl 25 ml;
Sodium bicarbonate (NaHCO3);
Magnesium sulfate (MgSO4);
*Equipment and glassware:*

Round bottom flask 50 ml;
Retort stand and clamp for securing apparatus;
Boiling chips;
Reflux condenser;
Glass rod and spatula;
Separatory funnel;
Heating plate;
Laboratory grade thermometer;
Laboratory scale (0.1-200 g is suitable);
Measuring cylinder 20 mL;
Funnel;
Filter paper;
Rotovap machine (optional);
Vacuum source (optional);
pH Indicator paper;
Beakers 100 ml x2 and 200 ml;
*Reaction scheme:*



​*Synthesis:*
*1*. A mixture of 1-phenyl-2-nitropropene (P2NP) 1.63 g, 10 mmol, powdered iron 3 g, FeCl3 0.6 g, and hydrochloric acid (HCl 36% aq.) concentrated 4 ml in toluene 5 ml and water 5 ml are stirred vigorously at 75 °C for 18 h in 50 ml flask with reflux condenser.
*2.* The resulting dark green suspension is cooled to room temperature and filtered. Layers are separated.
*3.* The aqueous layer is washed with an additional portion of toluene 10 ml, and toluene extracts are combined and washed with hydrochloric acid 3N (10.45%) HCl 25 ml, water 25 ml, saturated sodium bicarbonate (NaHCO3) aq. 25 ml, and water 25 ml successively to neutral pH 7.
*4.* The toluene solution is filtered and dried over anhydrous magnesium sulfate (MgSO4). Mixture is filtered from solids.
*5.* Toluene solvent is evaporated from the mixture. Phenyl-2-propanone (P2P; cas 103-79-7) is obtained as an orange oil. The yield is ~75%.​


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## btcboss2022

Hello,

I tried this synth but is practically impossible to move the magnetic stirrer, all the iron gets stuck on it not allowing to move( is normal about magnet) haahaha how do you fix that?

Thanks.




William Dampier said:


> *Reaction scheme:*
> View attachment 1476
> 
> *Synthesis:*
> 1. A mixture of 1-phenyl-2-nitropropene (1,63 g, 10 mmol), powdered iron (3 g), FeCl3 (0,6 g), and concentrated HCl (4 ml) in toluene (5 ml) and water (5 ml) was stirred vigorously at 75 *C for 18 h.
> 2. The resulting dark green suspension was cooled to room temperature and gravity filtered; the layers were allowed to separate.
> 3. The aqueous layer was washed with an additional portion of toluene (10 ml), and the toluene extracts were combined and washed successively with 3 N HCl (25 ml), water (25 ml), saturated sodium bicarbonate (25 ml), and water (25 ml).
> 4. The toluene solution was gravity filtered and dried over anhydrous magnesium sulfate.
> 5. Filtration followed by evaporation of the filtrate solvent yielded phenyl-2-propanone as an orange oil.



William Dampier


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## G.Patton

btcboss2022 said:


> Hello,
> 
> I tried this synth but is practically impossible to move the magnetic stirrer, all the iron gets stuck on it not allowing to move( is normal about magnet) haahaha how do you fix that?
> 
> Thanks.



btcboss2022top stirrer


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## KokosDreams

William Dampier said:


> *Reaction scheme:*
> View attachment 1476
> 
> *Synthesis:*
> 1. A mixture of 1-phenyl-2-nitropropene (1,63 g, 10 mmol), powdered iron (3 g), FeCl3 (0,6 g), and concentrated HCl (4 ml) in toluene (5 ml) and water (5 ml) was stirred vigorously at 75 *C for 18 h.
> 2. The resulting dark green suspension was cooled to room temperature and gravity filtered; the layers were allowed to separate.
> 3. The aqueous layer was washed with an additional portion of toluene (10 ml), and the toluene extracts were combined and washed successively with 3 N HCl (25 ml), water (25 ml), saturated sodium bicarbonate (25 ml), and water (25 ml).
> 4. The toluene solution was gravity filtered and dried over anhydrous magnesium sulfate.
> 5. Filtration followed by evaporation of the filtrate solvent yielded phenyl-2-propanone as an orange oil.



William Dampier
What's the obtained yield in P2P from this synthesis?
@btcboss2022
@G.Patton


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## ASheSChem

William Dampier said:


> Powdered iron (Fe)



William Dampieri see a lot of size for this reagent; any importance? 

i have see to sell :
300 mesh (36 µ) 
75 µm
90 μm 
100-300 µm


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## G.Patton

KokosDreams said:


> What's the obtained yield in P2P from this synthesis?
> @btcboss2022
> @G.Patton



KokosDreamsHello, sorry for a long reply. ~75%


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## KokosDreams

G.Patton said:


> Hello, sorry for a long reply. ~75%



G.PattonThanks for letting me know.


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## cokemuffin

ASheSChem said:


> i see a lot of size for this reagent; any importance?
> 
> i have see to sell :
> 300 mesh (36 µ)
> 75 µm
> 90 μm
> 100-300 µm



ASheSChempreferably at least 80-100 mesh.


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## ali.co

Hi
sorry but such a detail the proportions do not match
Other proportions in reagents
Other proportions in synthesis
I'm thinking about checking this synthesis
Long synthesis


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## G.Patton

ali.co said:


> Hi
> sorry but such a detail the proportions do not match
> Other proportions in reagents
> Other proportions in synthesis
> I'm thinking about checking this synthesis
> Long synthesis



ali.coHello, what do you mean about proportions?


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## CrystalBee

P2np to p2p



Add to a 500ml Round bottomed boiling flask (RBF) with 3 necks
central neck has an overhead stirrer - IMPORTANT has to be an overhead stirrer and has to be powerful enough to keep iron powder from settling on the bottom, cannot use magnetic stirring as it does not have enough power to keep the iron powder up in the solution and the iron messes with the magnetic stirring anyway.
side neck has a long reflux condenser with cold water supplied
2nd side neck has a pressure-equalising addition funnel filled with 0.197 mole of conc. hydrochloric acid 35.5% in the below example thats is 20.2 ml

The RBF is in a water or oil bath to keep internal reaction temperature at 85 to 95 degC.

Add to RBF:
0.1 mole of P2NP (P2NP 163.2 g/mole) = 16.23g of P2NP
0.715 mole of iron (Fe 55.85 g/mole) = 40g of iron (Fe) - cast iron turnings or ideally 40 mesh iron powder (powder 0.4 mm size)
Note: Activate a metal normally involves rinsing it with a strong mineral acid like hydrochloric acid or alkali like sodium hydroxide solution for a few minutes to remove any layer of oxidation that prevents it from reacting, after this rinse with distilled water twice and use immediately else store under non-polar liquid until ready use required.
However in this reduction of nitroalkene to ketone, hydrochloric acid is one of the reagents, therefore activation can occur in situ.

75ml of distilled water
0.1g of ferric chloride - acts as an initialization catalyst - helps reaction start faster

Acid from addition funnel is added slowly over 5 to 6 hours, so as to keep the reaction going but not explosively so, reflux should never reach over half way up the reflux condenser.
At the end the reaction mixture was then basified with 25% NaOH solution until pH 11 and then steam distill the P2P oil over to a receiver.
Yield should be 75 to 77% P2P from the P2NP ie. P2P 134.3 g/mol so 0.1 mole is 13.42g and 0.75 to 0.77 % yield = 10g (9.94ml) to 10.3g (10.24ml) (Density of P2P is 1.006 g/mL)

This reaction can be scalled up to quite a large size, the molar equivalents are:
molar ratio of Fe/alkene = 7.15
molar ratio of HCl/Alkene = 1.97
1.97 x 0.1 mole of p2NP=0.197 moles of HCl x HCl 36.458 g/mol = 7.18g HCl
if you have concentrated hydrochloric acid 35.5% that means it has 355g/L, or 35.5g/100ml so 718g / 0.355 = 20.2ml of concentrated hydrochloric acid 35.5% to be added via addition funnel

So a 1 mole reaction would use a 5L RBF with 163.2 g of P2NP, 7.15 mole of Fe (7.15 x 55.85 g/mol) = 400g of iron powder, 750ml of distilled water, 1g of Ferric Chloride and 202ml of concentrated hydrochloric acid 35.5%
Yield would be 100g (99.4ml) to 103g (102.4ml) of P2P


Note: For a cheap overhead stirrer:
From ebay you can get a cheap PTFE stirrer bearing to fit the correct size of your boiling flask central neck, you can get a steel stirrer coated in PTFE to protect it from the acid, you can get a bench supply that supplies 0-30V 0-3A for about £30, and you can get a DC motor from certain handheld blenders cheap which you can take apart and connect motor shaft to stirrer shaft, stirrer shaft goes through bearing (pre-grease internal bearing ring with vaseline to help reduce friction), connect the motor to the bench power supply, set the current high enough to supply to motor, then vary speed by increasing/decreasing voltage.

PTFE Standard Stopper Lab Stirrer Bearing Adapter Stirrer Accessory No.29
https://www.ebay.co.uk/itm/313672059695
£10.84
This will fit a 29/32 socket on a boiling flask, it uses a stirrer shaft of 8mm diameter
Findind a PTFE coated stirrer with shaft diameter 8mm tricky most on ebay 7mm so it maybe best to order both items from laborxing that's 2 weeks to arrive but they have high quality equipment.

https://www.laborxing.com/products/ptfe-stirrer-bearing-adapter-joint-stopper
https://www.laborxing.com/products/ptfe-stirring-blades-propeller-2-winged-length-250-mm-to-750-mm

Bench power supply 0-30V 0-10A - potentially this is powerful enough to run electrochemical reactions, and peltier cooling modules
https://www.amazon.co.uk/dp/B09ZQBFZ4C
£44.99
You should be able to find a cheaper one because you only need 0-3A, maybe if the motor you pick up is high torque then 0-5A


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