Producing gold nano flakes
I believe that ethylene glycol in this reaction is used as a solvent and Aniline is used as a reducing agent. Ethylene glycol solution heated with chloroauric acid produces $Au^{3+}$ ions (first 20 min) which is then reduced to $Au^{0}$  (3hr reaction) in the presence of aniline. Because there is no stirring during those 3 hrs (so less agitation of the reaction mixture)there is less formation of gold nanoparticle and more gold nano flakes are formed.

May be this paper will help you, it has a similar mechanism