Advantageous heterogeneously catalysed hydrogenation of carvone with supercritical carbon dioxide

Environmentally Benign Transformations of Monoterpenes and Monoterpenoids in Supercritical Fluids

“…Hydrogenation catalyzed by Rh catalyst yielded similar major products as those obtained in the Pdcatalyzed reaction; however, it was slower [64]. The major differences included incomplete conversion of carvone 61 and the detection of intermediate product carvotanacetone 64.…”

“…The Ru catalyst favors carvotanacetone 64 as a major product of the reaction (up to 25%), while carvomenthones 62 and carvacrol 63 were formed in smaller amounts [64]. The degree of conversion of carvone 61 was only 51% after 6 h at 323 K.…”

“…Full conversion of carvone 61 was achieved within 30 min during the hydrogenation over Pd/Al 2 O 3 under supercritical conditions [64], leading to the equilibrium mixture. Two stereoisomers of carvomenthone 62 at a 1.4:1 ratio were obtained as the main products (total content 77%) with the predominance of trans-isomer.…”

“…The hydrogenation of carvone 61 was investigated in high-density CO 2 over Pd, Rh, or Ru supported on Al 2 O 3 [64] (Scheme 17). The reactions with all these catalysts at 323 K proceeded faster in a supercritical phase (158 atm) than in a biphasic system (123 atm); however, the selectivities were very similar.…”

Platinum Nanoparticles Stabilized by Glycerodendrimers: Synthesis and Application to the Hydrogenation of α,β‐Unsaturated Ketones under Mild Conditions

“…The results are comparable to those obtained in our previously study concerning the efficiency of PtNPs stabilized by glycodendrimers,15b with the difference that the glycerodendrimers prepared herein are much easier to prepare and are less costly. Furthermore, this hydrogenation process is much more competitive to the hydrogenation of carvone and pulegone involving enzymatic catalysis,21 s ‐CO 2 extraction22 and electrochemistry 23…”