Recently I read about comet C/2014 Q2 (Lovejoy).The thing got me amazed was that scientists found it was dumping ethyl alcohol all along its way, at a rate of around 300-500 bottles per second. So I want to ask how common is alcohol in outer space, and how did it form? I usually imagine space as an inert mixture of dry dust and light gases but it turns out there are sometimes alcoholic compounds.
Getting atoms together into molecules requires two basic things - getting the reactants together and them providing the means to overcome the "activation energy" that is due to the mutual repulsion of the electrons that surround them.
Astrophysical chemistry is a rich and complex field of study. Most molecules are produced by a wide variety of processes. For ethanol in solar system objects, a cartoon of the process might be this:
Grains of dust (basic silicates and soot) form in the protosolar nebula; cosmic rays and high energy radiation from the protosun ionise atoms (remove outer electrons), which makes them "sticky"; these ionised atoms are concentrated onto the surfaces of dust grains, increasing their densities to the extent that reactions between them become likely; hydrogen ions are able to hydrogenate carbon and oxygen to produce CH and OH radicals; these then encounter each other in the presence of more hydrogen to form ethanol; dust grains with ethanol are then incorporated into solar system bodies like comets.
But as I said, for any individual ethanol molecule, other pathways are possible.