BromicAcid
International Hazard
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1,2-Dichloroethane from Acetylene and HCl
At one time this was one of the standard procedures to make dichloroethane and I have been unable to find any good information on it. I have heard
that dichloroethane is available OTC in some paint strippers but all I have found is trichloroethylene, and through my searching’s online for
1,2-dichloroethane it appears to have been put under some stringent regulations requiring hazmat and such and many places no longer carry it.
Anyway, the reaction between HCl and acetylene produces mainly 1,2 from what I've read and 1,1 to a lesser extent. But I haven't found
anything about the actual carrying out of the reaction itself, I don't even know (for a fact) if the reaction is usually carried out in the vapor
or aqueous phase or how to separate products. I could go out in my backyard and just blindly try a few things and I would probably
meet with some success, but I would rather get input from my fellow scientists here and possibly get a nice concrete procedure to follow.
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garage chemist
chemical wizard
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Why don't react ethylene with Cl2?
This gives the pure 1,2-dichloroethane.
Ethylene can be made by passing ethanol vapors (air-free) over strongly heated sand. No sulfuric acid is necessary. At the end of the heated sand
tube, there is a condenser which condenses excess ethanol and the formed water. Almost pure ethylene is thus had. React this with the same volume of
chlorine.
Perhaps the ethylene can be collected by water displacement in an inverted glass container in a bowl of water, and the chlorine bubbled in. The
dichloroethane should sink to the bottom of the bowl as little droplets, as it has a higher density than water.
Reacting acetylene with HCl would give toxic and highly carcinogenic vinyl chloride as the first product. I wouldn't try that.
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BromicAcid
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Yes, of couse I could just react ethylene with Cl2, but that would be a pain in the butt. A two part gas phase reaction, both gases needing to be
generated simultaneously and the ethane in this case being the product of a catalyst. Not only that but the slight possibility of an explosion from
their combination if not dilluted. I mean, that would be a nifty little procedure using the ineverted container over water, but the way I am
proposing would generate larger quantites relatively easier. Acetylene + HCl just seemed the easy way to go for me. Expecially if it works
appreciably in the aqueous phase. I could always add bromine or something else afterward to destroy any vinyl chloride.
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Eclectic
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Just give it a try? Bubble acetylene through aeration stone into bottom of a tall soda bottle of hydrochloric acid. The "Dutch liquid"
should accumulate on the bottom of the bottle if it works. Maybe a catalyst is needed? If so just add a pinch of rust...
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garage chemist
chemical wizard
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Vinyl chloride is a gas (bp -13,9°C), so if any heavy liquid collects on bubbling acetylene through HCl, it must be your dichloroethane.
Acetylene + HCl also happens to be the process for industrial vinyl chloride production.
Vinyl chloride is a rather inert substance as I read, therefore I doubt that it would react with HCl reasonably fast.
But it is always worth an experiment! If you succeed in making dichloroethane, it would be great.
Vinyl chloride isn't that nasty.
Only repeated or strong exposure can lead to nerve damage and liver tumors.
I have a fume hood and I could also try to bubble acetylene through HCl. I'll do it when I have time.
EDIT: Oh, I just read that the reaction of acetylene with HCl to vinyl chloride needs a 10% solution of HgCl2 as a catalyst.
Therefore we can forget about this.
Let's focus on the reaction of chlorine with ethylene.
[Edited on 10-3-2005 by garage chemist]
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