Title : Gas-phase dehydroisomerization of alpha-pinene to para-cymene catalyzed by metal oxides
Zn(II) and Zn(II)-Cr(III) oxides are demonstrated to be efficient, noble-metal-free catalysts for one-step dehydroisomerization of alpha-pinene to para-cymene in the gas phase. This is an example of the use of heterogeneous catalysis for the conversion of renewable feedstock into value-added chemicals. The reaction was carried out in a fixed-bed reactor at 350-370 oC to yield 90% of para-cymene at 100% alpha-pinene conversion. The catalysts showed stable performance for over 24 hours. The proposed reaction mechanism involves acid-catalyzed alpha-pinene isomerization followed by dehydrogenation of para-cymene precursors.