C4 hydrocarbons to value-added chemicals over Keggin-type heteropolyacids: structure-properties, reaction parameters, and mechanisms

Decades of heavy reliance on petroleum refineries for energy have led to perpetual environmental pollution. These emissions include sulfur oxides, nitrogen oxides, carbon monoxide, and C1-C4 light hydrocarbons. Researchers worldwide strive to convert these pollutants into value-added products using catalysts. The current review provides a comprehensive overview of valorization of C4 hydrocarbons into value added chemicals, including methacrolein, methacrylic acid, or methyl methacrylate using a green solid catalyst, Keggin-type heteropolyacids. In this review, structures and properties related to catalytic activities are discussed, with the focus on the advancements of Keggin-type heteropolyacids. The influencing factors of the process design are then discussed and succeeded by mechanistic pathways. It is a timely review to place emphasis on sustainable and green chemistry resolution, meanwhile, advocating Sustainable Development Goals No. 8 Affordable and Clean Energy and No. 12 Responsible Consumption and Production.