Conversion of glycerol to acrylic acid: A review of strategies, recent developments and prospects

Acrylic acid is an essential chemical and a vital intermediate used in the production of various commodities and industrial chemicals. However, continued reliance on petroleum-based feedstocks for the production of acrylic acid is considered unsustainable and even counterproductive to the goal of achieving net zero carbon emissions. Glycerol waste generated from biodiesel production via transesterification processes has been identified as a viable alternative feedstock. However, commercial-scale adoption is yet to be realised due to inherent challenges associated with the conversion of glycerol to acrylic acid. Herein, we review the latest strategies, challenges and prospects for the utilisation of waste glycerol as a feedstock for the production of acrylic acid. Biochemical, electrochemical, photochemical, electrocatalytic and thermocatalytic conversion routes are discussed to provide insights into recent developments made in the field. Sustainable pathways that can be potentially implemented to transform readily available waste glycerol to acrylic acid at minimal costs are also considered. Biochemical conversion routes are the most promising from an environmental perspective as they have minimal energy requirements and low global warming potentials. However, higher acrylic acid yields have been reported from thermocatalytic conversion routes.