$$\ce{R-NO2 +C2H5OH + H2 (g)->[Pt/Pd/Ni] R-NH_2}$$

The above equation represents catalytic reduction of nitro group to amine. What is the role of ethanol in it?

I understand that $\ce{Pt/Pd/Ni}$ plays an important role as reducing agent and hydrogen gas replaces oxygen atoms. But, I'm not able to understand the role of ethanol. Can someone help me with this?

  • 1
    $\begingroup$ Solvent? You're missing the actual reductant, which is presumably hydrogen gas. $\endgroup$ – orthocresol Dec 13 '17 at 0:28
  • 2
    $\begingroup$ Provide conditions. Ethanol may be the reductant. $\endgroup$ – user55119 Dec 13 '17 at 0:48
  • 1
    $\begingroup$ The above equation does not represent the catalytic reduction of a nitro compound to an amine! As mentioned by @orthocresol, you're missing the hydrogen gas! I've done the reaction very often with nitro arenes. Ethanol as a solvent is great because it dissolves both starting materials and products (only the catalyst, e.g. Pd/C is suspended and can be filtered off later). It is cheap, can be removed easily on a rotavap and, in contrast to methanol, isn't overly harmful. $\endgroup$ – Klaus-Dieter Warzecha Dec 13 '17 at 11:40
  • $\begingroup$ I'm terribly sorry for not mentioning Hydrogen. I did miss a really important reactant there. And thank you @Klaus-DieterWarzecha for making me understand the role of ethanol as a solvent. $\endgroup$ – Sashank Sriram Dec 13 '17 at 13:23
  • $\begingroup$ Note that Pt/Pd/Ni is definitely a catalyst here and should be denoted differently (not as reactant). I suppose the same goes for the ethanol (solvent), but since it's a part of a question, I left it as it is, but still the reaction is incomplete. Is there water among the products? $\endgroup$ – andselisk Dec 22 '17 at 4:53