Applications of Alum (KAl(SO4)2.12H2O) in Organic Synthesis and as Catalysis: A Quinquennial Update (2017-2022)

Recently, synthetic scientists have become interested in potassium alum (KAl(SO4)2.12H2O), also referred to as "alum," as an effective, safe, and environmentally friendly acid catalyst for carrying out various organic transformations. The current mini-review piece provides an overview of the representative catalytic uses of this easily accessible and inexpensive inorganic sulphate salt in organic reactions that have been reported from mid-2017 to the present.