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.