How do you knock off a halogen from a hydrocarbon chain?

[Simfish]

Without introducing any other atoms or double bonds into the chain? (just replace the halogen with a hydrogen atom). Assume for now that the halogen was introduced in the middle of the carbon chain.

 

[Simfish]

Okay I think I solved it.

Dehydrohalogenation removes the halogen and the attached carbon forms a double bond with another carbon. But then hydrogenation of this double bond into a single bond is spontaneous (it just needs a catalyst to speed up).

 

[DDTea]

Pretty much. Yes, it's going to be two separate reactions. Next, you need to reduce the double bond somehow, as by catalytic hydrogenation: i.e., high pressure H2 + a suitable transition metal (Ni, Pd, Pt, Rh, etc).

 

[chemisttree]

That's one way. Another is to treat with Na or K or Li and work up with water. Your way is better for large quantities.