Traditionally, eugenol and safrole are extracted from plants; however, in recent times produced synthetically for fragrance application. The isomerized product iso-eugenol are used in different aroma industries, in perfumery, insect attractant formulations, UV absorbers, medicine (local antiseptic and analgesics) and for the production of vanillin and ferulic acid. Similarly, iso-safrole, a major raw material in flavor industry to produce piperonal, ethyl vanillin, and vanillin with dense flavor (Catalysis Today, 141 (2009) 176 Applied Catalysis A General, 270 (2004) 227 Green Chemistry, 4 (2002) 607 Journal of Molecular Catalysis, 223 (2004) 225)
- Low-cost and easily synthesizable catalyst with non-precious metals (layered double hydroxides, LDHs).
- Highly active solid base catalysts are prepared from precursors by simple co-precipitation process.
- High yield was obtained by hydrotalcite (HT) with Mg/Al atomic ratio 4 (MgAl4-HT) for eugenol and MgAl6-HT for safrole
- High boiling solvents such as DMF or DMSO showed high activity at 200ºC
- Up to 98% conversion of eugenol and safrole was achieved with 85 to 95% selectivity of trans product, and importantly no by-products obtained.
- Both cis and trans isomers have similar perfumery notes in large number of cases and hence, are dispensable to separate.
- Catalyst is recyclable
Isomerization of eugenol has been scaled up at 50 g and achieved 90% conversion.
Isomerization of alkenyl aromatics used in perfumery has been practised commercially using alkalis such as KOH in alcoholic solutions (most often in higher alcohols) at high temperatures, homogeneous complex catalysts also require high quantity of alkali which are associated environmental issues. Heterogeneous catalyst used here can be separated easily and can be reused multiple times. Simple and scalable method is used for the preparation of low-cost catalyst precursors using water as synthesis medium. Catalyst is separated from the reaction mixture by simple filtration without using any further chemicals and are successfully recycled
Catalyst is easily recoverable (simple filtration) without any further addition of chemicals and reusable; No large aqueous alkaline/salt effluent is generated in the process
Eugenol and Safrole
For reaction - Stirred tank reactor with water cooler system; Filtration assembly; Rotary evaporator to remove the solvent.
As the catalyst cost is inexpensive, the cost of product would be 1.5-2.0 times that of reactant cost; Available on request
Know-how for process of isomerization of eugenol and safrole; Demonstration of the process; Equipment necessary for pilot scale; License fee, royalty and other financial details are available on request
