Conversion of crude and pure glycerol into derivatives: A feasibility evaluation

The transformation of glycerol to derivatives has been widely investigated because of the demand to enhance the value of crude glycerol produced by biodiesel and oleochemical industries. Intensive research has focused on the conversion of pure glycerol (PG) to different valuable derivatives. Nevertheless, the feasibility of the direct conversion of crude glycerol (CG), which is a waste byproduct of biodiesel production, through chemical processes has been rarely reported because this application is limited by the impurities of CG. Therefore, this review evaluates the feasibility of the direct transformation of CG to value-added derivatives, supplemented with the performance comparison of both PG and CG. This review also demonstrates that the relevant approaches to transform CG into value-added derivatives mainly rely on the following factors: acceptable production cost, advanced process technology, convenient final product separation and purification, excellent product specification, appropriate CG feedstock quality, and minimum catalyst deactivation problem.