The Vespiary

The Hive => Chemistry Discourse => Topic started by: timsong on November 12, 2001, 01:12:00 PM

Title: Methylene Dichloride Chlorination
Post by: timsong on November 12, 2001, 01:12:00 PM

Can anybody help me with the details on how to chlorinate Methylene Dichloride to Carbon Tetrachloride.

Do I need to gas the M-D-C at reflux temp ?
Does light (u.v) need to be present ?


This is all I know at present :-

In diffused light methane reacts quietly with chlorine to give a series of products by the successive replacement of hydrogen atoms :

CH4 + Cl2 = HCl + CH3Cl (methyl chloride)
CH3Cl + Cl2 = HCl + CH2Cl2 (methylene dichloride)
CH2Cl2 + Cl2 = HCl + CHCl3 (chloroform)
CHCl3 + Cl2 = HCl + CCl4 (carbon tetrachloride)

Title: Re: Methylene Dichloride Chlorination
Post by: Rhodium on November 12, 2001, 02:32:00 PM

This is too hard to do at home.

Title: Re: Methylene Dichloride Chlorination
Post by: timsong on November 12, 2001, 03:38:00 PM

For what reasons is this too hard to do at home ?

(beyond the capabilities of glass labware ?)

Title: Re: Methylene Dichloride Chlorination
Post by: Rhodium on November 12, 2001, 03:45:00 PM

It is usually done in the gas phase with chorine and radical initiators (or UV light). Hot chlorine is not something you want to have around.

Title: Re: Methylene Dichloride Chlorination
Post by: lugh on November 12, 2001, 04:14:00 PM

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For what reasons is this too hard to do at home ?

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Hot chlorine gas is very obnoxious (and one mistake could be your last), corrodes many common materials and due to minor leakage when using it needs to be confined in a very efficient fume hood. Leave this stuff to the pros, it's definitely not a very good idea for the less experienced.

Title: Re: Methylene Dichloride Chlorination
Post by: timsong on November 12, 2001, 04:28:00 PM

Thanks for the advice guys.

I was playing with idears on how to make carbon tetrachloride, as the stuff is not sold otc in the UK anymore (nanny state), or even used in fire extinguisers anymore (I think kids used to sniff them).
Carbon tetrachloride would be an easy route to making chloroform. I'll just have to do that messy old acetone+calcium hypochlorite reaction again.