Sciencemadness Discussion Board - Thionyl chloride

Thionyl chloride

numos - 6-12-2015 at 19:44

So I have started a synthesis of Rubrene and I have nearly everything except for the Thionyl chloride which is required to initiate the final dimerization.

I'm a little worried as this chemical has some legal involvements with chemical weapons. So I am at a loss at how to procure a small sample ~50ml or so.

I can obviously buy directly from Sigma Aldrich, I seem to have found a way to get them to ship to me, but my wallet would take a beating... have you seen the shipping charges!? - If you haven't, it's nothing a private individual should have to deal with.

Preparation seems like a disaster waiting to happen, utilizing multiple gas state reactants does not sound like fun.

Ideally some small private supplier would have some for sale, but I keep coming back empty handed.

Any ideas?

careysub - 6-12-2015 at 19:55

Quote: Originally posted by numos

So I have started a synthesis of Rubrene and I have nearly everything except for the Thionyl chloride which is required to initiate the final dimerization.

I'm a little worried as this chemical has some legal involvements with chemical weapons. So I am at a loss at how to procure a small sample ~50ml or so.

I can obviously buy directly from Sigma Aldrich, I seem to have found a way to get them to ship to me, but my wallet would take a beating... have you seen the shipping charges!? - If you haven't, it's nothing a private individual should have to deal with.

Preparation seems like a disaster waiting to happen, utilizing multiple gas state reactants does not sound like fun.

Ideally some small private supplier would have some for sale, but I keep coming back empty handed.

Any ideas?

The small scale synthesis book describes the production of chlorosulfonic acid and thionyl chloride together in a relatively tractable procedure. Still pretty severe, it involves chlorinating oleum.

solo - 6-12-2015 at 19:59

.....try using, Cyanuric chloride is an organic compound with the formula (NCCl)3. This white solid is the chlorinated derivative of 1,3,5-triazine.

......solo/java

plastics - 7-12-2015 at 09:55

Quote: Originally posted by numos

This might be an alternative - I was lucky to have some thionyl chloride but nearly chocked on the copious HCl fumes produced. The final stage results in a sticky syrup that needs a fearsome vacuum to enable the product to solidify (0.05mmHg)

Methanesulfonyl chloride is still not particularly easy to get hold of and is rather toxic. The method does actually work! The quantities specified are my own for scaling up/down

Attached is the reference I used

Synthesis of rubrene from 1,1,3 triphenylprop-2-yn-1-ol

1,1,3-triphenylprop-2-yn-1-ol 2g 4g 6g 8g 10g
Dichloromethane (39.4 °C) 15ml 30ml 45ml 60ml 75ml
Triethylamine 1.1ml 2.2ml 3.3ml 4.4ml 5.5ml
Methanesulphonyl chloride (161 °C) 1.2ml 2.4ml 3.6ml 4.8ml 6.0ml
Collidine (171 – 172 °C) 1ml 2ml 3ml 4ml 5ml
Xylene (140 °C)

2.0 g 1,1,3-triphenylprop-2-yn-1-ol is dissolved in 15 ml anhydrous dichloromethane under nitrogen and cooled to 0 °C
1.1 ml anhydrous triethylamine and 1.2ml methanesulphonyl chloride were added and the mixture stirred for 1 hour at 0 °C, then allowed to warm to room temperature
The mixture was heated at reflux to distil off the dichloromethane which was gradually replaced with xylene
The solution was heated and on reaching 80 °C 1ml collidine added dropwise
Reaction temperature raised to 95 °C and held at this temperature for 7 hours
Mixture allowed to cool to room temperature and the precipitate collected by filtration
The red soldid was recrystallized from ethanol to afford the desired product yield 0.76 g (46%)

Attachment: Braga_EurJOrgChem_2011_4160to4169.pdf (452kB)
This file has been downloaded 492 times

numos - 4-2-2016 at 15:19

So I've acquired some Thionyl chloride, and I'm very confused as to the procedure. I found this in Vogel's 5th addition,

"This substituted allene is formed in situ from 1,1,3-
triphenylprop-2-yn-l-ol (Expt 5.41) when the latter is allowed to react with
thionyl chloride and the resulting chlorosulphite ester heated with a little
quinoline; cyclisation occurs spontaneously under these reaction conditions to
give rubrene which has an intense red colour."

This is a theoretical procedure and does not provide work up / purification. I was doing a little experimentation of my own, treating 1,1,3-triphenylprop-2-yn-l-ol with thionyl chloride produces a deep violet solution - but the substance has no florescence. Does anyone have a practical procedure? Plastics, I'd really like to see the one you mentioned using Thionyl chloride.

Edit: I did try the method using Methansulfonyl chloride but it does not seem to work with pyridine and collidine is way to exotic.

Edit: This is probably the wrong place to post this, but I did not want to start a new thread about the same subject.

[Edited on 2-4-2016 by numos]

[Edited on 2-4-2016 by numos]

Dr.Bob - 4-2-2016 at 15:36

Vogel uses quinoline as the base, that is another pyridine family member. You need to mix the allene with thionyl chloride to form the chlorosulfite ester, then mix that with a pyridine base and heat that mix to generate the rubrene. You will know it works when it turns red.

Nice scheme for this at https://commons.wikimedia.org/wiki/File:Rubrene_Synthesis_va...

numos - 4-2-2016 at 16:11

Quote: Originally posted by Dr.Bob

Vogel uses quinoline as the base, that is another pyridine family member. You need to mix the allene with thionyl chloride to form the chlorosulfite ester, then mix that with a pyridine base and heat that mix to generate the rubrene. You will know it works when it turns red.

Nice scheme for this at https://commons.wikimedia.org/wiki/File:Rubrene_Synthesis_va...

Ok so I tried this right away, using pyridine as a pyridine base. It immediately forms a brown precipitate, even before heating. I have been using 1 molar equivalents for all reactants, so I'll give it a try with heating.

Edit: Same problem, forms a deep red goo upon addition of thionyl chloride, and a brown precipitate when pyridine is added. The red goo is ever so slightly florescent, so some Rubrene may be present, even so I have found no to way to purify this.

[Edited on 2-5-2016 by numos]

plastics - 5-2-2016 at 00:47

Quote: Originally posted by numos

So I've acquired some Thionyl chloride, and I'm very confused as to the procedure. I found this in Vogel's 5th addition,

"This substituted allene is formed in situ from 1,1,3-
triphenylprop-2-yn-l-ol (Expt 5.41) when the latter is allowed to react with
thionyl chloride and the resulting chlorosulphite ester heated with a little
quinoline; cyclisation occurs spontaneously under these reaction conditions to
give rubrene which has an intense red colour."

This is a theoretical procedure and does not provide work up / purification. I was doing a little experimentation of my own, treating 1,1,3-triphenylprop-2-yn-l-ol with thionyl chloride produces a deep violet solution - but the substance has no florescence. Does anyone have a practical procedure? Plastics, I'd really like to see the one you mentioned using Thionyl chloride.

Edit: I did try the method using Methansulfonyl chloride but it does not seem to work with pyridine and collidine is way to exotic.

Edit: This is probably the wrong place to post this, but I did not want to start a new thread about the same subject.

[Edited on 2-4-2016 by numos]

[Edited on 2-4-2016 by numos]

Hi numos

If you look at p844 in Vogel 5th ed there is a more detailed prep of rubrene using thionyl chloride. I did pursue this method and ended up with a dark red residue. I couldn't get it to solidify/crystallise and didn't have a good enough vacuum pump to distill it (as recommended). I carried on with the prep but didn't get any red crystals at the end - just the same thick 'goo'

zed - 12-2-2016 at 15:51

A problem I have had. If you cannot vacuum distill it, and you don't have a seed crystal, like Honey, your sample might eventually crystallize. Or, not. Could be years.

Short path, vacuum distillation, would appear to be the solution. A Harbor Freight vacuum pump should do the trick. I obtained a decent one, on super sale, for about a hundred bucks a few months back.

Ummm. Could try to sublimate a little bit, onto a cold finger. And then use the resultant seed crystal, to kick off the rest. Or, you could try to use column chromatography, to elute what you want, and ditch the rest.