Silica-supported polyphosphoric acid (PPA-SiO₂): An efficient and reusable heterogeneous catalyst for ecofriendly organic synthesis

ABSTRACT

This review discusses the advances in the use of silica-supported polyphosphoric acid (PPA-SiO₂) as a green and reusable heterogeneous catalyst in the preparation of various organic compounds and pharmaceutical intermediates. PPA-SiO₂ could be recovered and reused several times without significant loss of their efficiency. In this review, we attempt to give an overview of the applications of PPA-SiO₂ as a catalyst in condensation, cyclization, and addition reactions for the preparation of various organic compounds.

GRAPHICAL ABSTRACT

KEYWORDS:

• Green synthesis
• heterogeneous catalyst
• organic synthesis
• silica-supported polyphosphoric acid (PPA-SiO₂)
• solid acid catalyst

Acknowledgments

The authors are thankful to the Department of Chemistry, Gujarat University, Ahmedabad, for providing the necessary facilities. UGC-Info net and INFLIBNET Gujarat University are acknowledged for providing the e-source facilities.