Novelties of eclectically engineered sulfated zirconia and carbon molecular sieve catalysts in cyclisation of citronellal to isopulegol

Sulfated zirconia (S-ZrO2) is a well-known solid superacid catalyst used in various reactions of commercial importance such as isomerisation, alkylation and acylation, nitration, etc. The selectivity towards the formation of isopulegol, a potential intermediate in the synthesis of menthol, can be drastically increased by using carbon molecular sieve (CMS) with S-ZrO2.