The synthesis of oxygenated fuel additives via solvent freebase-catalyzed etherification of glycerol is reported. The products of glycerol etherification arediglycerol (DG) and triglycerol (TG) with DG being the favorable one. The catalytic activity of different homogeneous alkali catalysts (LiOH, NaOH, KOH and Na2CO3) was investigated during the glycerol etherification process. LiON exhibited an excellent catalytic activity during this reaction, indicated by the complete glycerol conversion with a corresponding selectivity of 33% toward DG. The best reaction conditions were a reaction temperature of 240 degrees C, a catalyst/glycerol mass ratio of 0.02 and a reaction time of 6 h. The influences of various reaction variables such as nature of the catalyst, catalyst loading, reaction time and reaction temperature on glycerol etherification were elucidated. Industrially, the findings attained in this study might contribute towards promoting the biodiesel industry through utilization of its by-products. (C) 2012 Elsevier Ltd. All rights reserved.