Although biodiesel-derived CG produced the highest and complicated impurities, the direct preparation of impure value-added chemicals has provided new outlets and profit margin for biodiesel investors. Currently, the potential value-added derivatives that can be prepared directly from CG are hydrogen gas, polyglycerols Findings showed that the heterogeneous-catalytic preparation of propylene glycol and acrolein directly from CG is not currently feasible. In summary, the factors necessary to evaluate the feasibility of the use of CG as a starting material include the following: acceptable production cost, advanced process technology, convenient final product separation and purification, excellent product specification, appropriate CG feedstock quality, and minimum catalyst deactivation problem.