Question

Starting with `"ethyl chloride"`, how could we make `"n-butane"`?

Answer 1

Via a Grignard reagent ..... it is not a sequence I would want to perform, especially as I could buy butane in a bottle.

Explanation:

And here we use the ethyl chloride as the only organic starting material.

`i.` `H_3C-CH_2Cl + Mgstackrel("dry ether")rarrH_3C-CH_2MgCl`

`iia.` `H_3C-CH_2Cl + NaOHrarrH_3C-CH_2OH + NaCldarr`

`iib.` `H_3C-CH_2OH + K_2Cr_2O_7stackrel"pyridine"rarrH_3C-C(=O)H + "inorganic salts"`

`iii.` `"H"_3"CC(=O)H" + "H"_3"CCH"_2"MgCl"rarr"H"_3"CC(O"^(-)")""HCH"_2"CH"_3`

`iv.` `"H"_3"CC(O"^(-)")""H"_2"CHCH"_3stackrel(H_3PO_4, Delta)rarr"H"_3"CCH=CHCH"_3+"H"_2"O(l)"`

`v.` `"H"_3"CCH=CHCH"_3+H_2stackrel(Pd)rarr"n-butane"`

A lot of work for an alkane. We could simply drill a hole in the ground and tap off the gas.......

Answer 2

How about a Wurtz reaction?

Explanation:

You react the ethyl chloride with sodium in dry ether.

`"CH"_3"CH"_2"Cl" + "2Na" + "ClCH"_2"CH"_3 stackrelcolor(blue)("dry ether"color(white)(mm))(→) underbrace("CH"_3"CH"_2"CH"_2"CH"_3)_color(red)("butane") + "2NaCl"`