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Topic: Sulfinyl chloride preparation problem  (Read 2512 times)

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Offline Ingeniosuccinimide

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Sulfinyl chloride preparation problem
« on: October 24, 2013, 06:04:55 AM »
Hello everyone,

I'm trying to prepare benzenesulfinyl chloride according to the following procedure for p-toluenesulfinyl chloride (except I used 6x smaller amounts):

http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=cv4p0937

but the first try was unsuccessful.

 The problem occours when I try to separate the impure product from the inorganic salt. The link above states that ''crude sulfinyl chloride... ...which are decanted without difficulty from most of the inorganic residue''.

However, what I get after adding dry ether is a slurry which is almost impossible to separate. What can I do to solve or avoid the slurry formation?

Offline Archer

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Re: Sulfinyl chloride preparation problem
« Reply #1 on: October 24, 2013, 09:35:28 AM »
Please provide the procedure that you recorded in your lab book, volumes weights etc.

That way we may be better able to assess where the experiment went wrong.
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Offline Ingeniosuccinimide

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Re: Sulfinyl chloride preparation problem
« Reply #2 on: October 25, 2013, 04:15:07 PM »
Ok, if you are willing to help, I'll be glad to add a description:

I poured 17.7 ml of thionyl chloride in a 50 ml round-bottomed flask, and added 5 g of finely powdered brand new (1st time opened bottle) sodium benzenesulfinate in small portions at room temperature over a 10 minute period. The mixture turned light yellow and was opaque, gas started to develop, temperature of reaction rose to around 30 °C and it remained unchanged (1st weird thing) for around 30 minutes. Immediately after the solid was added (10 minutes I earlier mentioned), a calcium chloride drying tube was attached and mixture was set aside to stir at room temperature for 2 hours. The mixture is still opaque after that period and has a moderate smell of SO2.

Excess thionyl chloride was removed by distillation under reduced pressure (I don't know the pressure, but I used common water pipe pump) and the bath temperature was around 40°C. The 2nd weird thing here was that thionyl chloride did not condense into the receiving flask, but it simply (I guess?) was sucked out through vacuum duct. However, the quantity of liquid in the reaction mixture flask decreased significantly and now was a yellow slurry.

After that I added 20 ml of anhydrous ether in two portions. The residue consisted of a yellow opaque slurry (3rd weird thing). There were no granules of any kind. I evaporated most of the solvent on roatavapor, but the slurry remained unchanged, except that it became slightly pale. After that, following the cited procedure, I added more anhydrous ether, but there was very little separation of phases and it was nearly impossible to separate it, and not to talk about decantation (cited procedure).

I tried to filter the mixture. I used sintered glass filter, and the one with highest porosity was totally unsuitable, so the one with higher porosity was used. All I obtained was around 2 ml of pale liquid that still had the smell of SO2, and I did not distill that, as it was obviously useless...

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