Catalytic transformation of camphene over alumina, silica-alumina and zeolite catalysts

Abstract

Isomerisation of camphene in the vapour phase over alumina prepared from aluminium foil, alu-minium isopropoxide, aluminium sulphate and aluminium nitrate, silica-alumina in different ratios (0.88,1.86,3.16) and zeolites such as H-5A, H-ZSM-5, H-Y has been studied. The products formed are tricyclene, bomylene and monocyclic terpenes. The product distribution is influenced by the acidic strength of the catalysts. Maximum amount of tricyclene is formed over lower acidic strength while maximum amounts of monocyclics like dipentene, terpinolene, ɑ-and-&tau;-terpinenes, <em>p</em>-menthene and <em>p</em>-cymene are formed over higher acidic strength. The concentration of bornylene in the product increases with acidity. The effects of temperature, contact time and partial pressure of pyridine on the conversion and product distribution have also been investigated.