Vanadium-containing nickel phosphate molecular sieves (V-VSB-5) were applied as heterogeneous catalysts for the liquid phase oxidation of alpha-pinene with molecular oxygen at 60 degrees C. It has been found that the vanadium content in V-VSB-5 materials affects the conversion of alpha-pinene and product distribution. The conversion of alpha-pinene increases with increasing of V content. The major products were alpha-pinene oxide, verbenol and verbenone. Acid-base properties of V-VSB-5 affect the distribution of by-products formed via the isomerization of alpha-pinene oxide over Lewis acid sites and Bronsted acid sites to campholenic aldehyde and trans-carveol. The increase in V content in V-VSB-5 leads to the increase in isomerization of alpha-pinene oxide to trans-carveol and decrease in that to campholenic aldehyde. (C) 2012 Elsevier B.V. All rights reserved.