The cyclic olefin, 3-carene, undergoes an isomerization of the carbon- carbon double bond to produce 2-carene, a precursor in the synthesis of (-)- menthol. This isomerization is observed over silica supported nickel, but the selectivity is reduced by side reactions producing trimethylheptenes by hydrogenative ring opening of the cyclopropyl ring. Selectivity for C=C bond isomerization is dramatically increased by surface modification of the nickel metal catalyst by reaction with tetra-n-butyl tin. The most selective of these silica supported nickel/tin catalysts produces 2-carene with 91% selectivity at 48% conversion.
- Carene isomerization
- Ni/SiO catalyst
- Surface organometallic chemistry
- Tetra-n-butyl tin modified catalyst
ASJC Scopus subject areas
- Process Chemistry and Technology
- Physical and Theoretical Chemistry