Sciencemadness Discussion Board - p-Dichlorobenzene and Ferric Chloride

p-Dichlorobenzene and Ferric Chloride

Meltonium - 29-11-2016 at 08:12

I need some ferric chloride to create some p-chlorobenzene. Unfortunately, I have none on hand. Would simply adding some steel wool to benzene and bubbling the chlorine through be enough to make ferric chloride, or would that only produce ferrous chloride?

The reaction I am hoping to preform is:
C6H6 + 2Cl2 + FeCl3(catalyst) -> C6H4Cl2 + 2HCl

JnPS - 29-11-2016 at 09:01

That sounds like it would work,...you could always just dissolve an iron source in HCl and carefully boil it down to get some FeCl3 but making it in situ should work just as well, just make sure you account for it when calculating how much Cl2 to generate.

Out of curiosity how do you plan on separating any o-dichlorobenzene, chlorobenzene, or trichlorobenzene products?

Texium - 29-11-2016 at 09:19

Yes, that should work. I used a very similar procedure to make bromobenzene, by placing a stir bar wrapped in aluminum foil in a flask of benzene, and then adding bromine slowly with stirring. Anhydrous aluminum bromide was produced in situ that way, and I got a good yield of bromobenzene.

DraconicAcid - 29-11-2016 at 09:31

That should work just fine.

violet sin - 29-11-2016 at 09:36

p-DCB is the only kind of moth controll I see in the stores here. Napthalene is not california compliant. Dirt cheap, and everywhere but I assume that is not as fun as making it would be. I just try to avoid making things that are cheap to buy as it robs my time for things that can't be bought. I know all things are not available everywhere, so excuse the suggestion if it's not available there.

Meltonium - 29-11-2016 at 17:40

Quote: Originally posted by violet sin

p-DCB is the only kind of moth controll I see in the stores here. Napthalene is not california compliant. Dirt cheap, and everywhere but I assume that is not as fun as making it would be. I just try to avoid making things that are cheap to buy as it robs my time for things that can't be bought. I know all things are not available everywhere, so excuse the suggestion if it's not available there.

Wow! Thanks for bringing that to my attention! I didn't know it was used as a moth repellent. But you're right, it's not as fun as making it.

CuReUS - 30-11-2016 at 01:20

To have even more fun,why go via the straight forward FeCl₃/Cl₂ route which is low yielding,messy and gives tons of isomers which are difficult to separate.Why not start off with aniline and do this ?
1.p-chlorination of aniline -https://erowid.org/archive/rhodium/chemistry/aromatic.bromin...
2.diazotization followed by sandmeyer to get p-DCB

Quote:

diazotization procedure:- 50 mmol of 4-chloroaniline was dissolved in 12 ml of concentrated HCl which was then diluted to 50ml and diazotized at 5-10'C using 3.5 g of NaNO₂ in 12 ml of H₂O

sandmeyer on the diazonium salt -http://www.sciencedirect.com/science/article/pii/S0040403900...

[Edited on 30-11-2016 by CuReUS]

wg48 - 30-11-2016 at 05:00

Quote: Originally posted by Meltonium

Quote: Originally posted by violet sin

Wow! Thanks for bringing that to my attention! I didn't know it was used as a moth repellent. But you're right, it's not as fun as making it.

DCB may also still be used as urinal block in your location.

One more point. I don't think you can make the anhydrous ferric chloride via a simple wet method and my understanding is in the direct route ie chlorine and steel wool you need to heat the steel to red heat.

AJKOER - 30-11-2016 at 05:56

A possible new variation of the direct action of iron with dry chlorine gas, which avoids heating the iron:

1.Prepare ferric oxalate as a path to pyrophoric iron (see http://www.amazingrust.com/Experiments/how_to/Pyrophoric_Fe.... ). Not sure if rapid heating ferric acetate and restricting air access or adding carbon would work here also, apparently in air some FeO product (which may be reduced by the added carbon to Fe), only if one applies rapid heating to the ferric acetate, else Fe2O3, see http://link.springer.com/article/10.1007/BF01981811 .

2. Heat the dry salt in a test tube limiting oxygen exposure.

3. Sprinkle the resulting very fine iron powder (which should produce sparks if sprinkled in air) into a large cooled vessel containing dry Cl2.

4. Add more chlorine to ensure that the Cl2 is in excess, which should reduce the possibility of FeCl2 contamination (a possible issue in subsequent use of the iron chloride product).

Enjoy the show and collect the FeCl3 liquid.

Note: Placing a hot iron rod (where the iron is excess) in contact with a limited supply of chlorine gas may introduce ferrous chloride per the reaction of Fe + FeCl3 (see, for example, https://www.youtube.com/watch?v=QFfzfzPG-Fw ).
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A variation of the above, purchase zero valent iron powder to add to the dry chlorine.
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[Edit] The simplest, but possibly problematic embodiment, for small scale production of FeCl3, may be just to place dry chlorine in a large glass vessel filled with the stoichiometric amount or less of ordinary iron powder. The vessel is loosely sealed with a pin hole or plastic wrap to allow for any gas expansion resulting from short pulse irradition of the vessel in a microwave. Caution: under these conditions, the iron metal naturally produces sparks and high temperatures. Cool to collect the FeCl3.

Testing on a very small scale, with short pulses, is also wise as my prior experience suggests a possibly very exothermic reaction that may crack the containment vessel, so placing the iron powder on a porcelain tile or plate in the vessel may be required.

[Edited on 30-11-2016 by AJKOER]

[Edited on 30-11-2016 by AJKOER]

Amos - 30-11-2016 at 06:53

Quote: Originally posted by JnPS

That sounds like it would work,...you could always just dissolve an iron source in HCl and carefully boil it down to get some FeCl3

The OP needs anhydrous FeCl3 for the catalysis, which can't be prepared from hydrogen chloride in solution.