Catalytic conversion and mechanism of glycerol into various value-added products: A critical review

Glycerol (GL) is a low-cost byproduct of biodiesel industries, which accounts for 10 wt% of biodiesel generation. As the biodiesel industries grow, the need for GL utilization is also gaining attention worldwide. Crude GL can be converted into other valuable molecules rather than disposed of. GL is a particularly appealing starting point for the creation of a wide variety of specialized compounds due to its quick bioavailability, renewability, and distinctive structure. In this review, (1) purification of GL, (2) various organic transformations of GL, such as transesterification (formation of GL carbonate), esterification (formation of acetin), dehydration (formation of acrolein), etherification (formation of GL ethers), and acetalization (formation of solketal), by various heterogeneous catalysts, and (3) mechanisms related to these organic transformations have been discussed. At last, challenges in utilization and future scope have been added for further development of various heterogeneous catalysts.