Supported Cobalt Catalysts for Acceptorless Alcohol Dehydrogenation. Issue 6 (22nd June 2020) - Kaźmierczak, Kamila
Abstract: The acceptor‐less dehydrogenation of 2‐octanol was tested over cobalt supported on Al2 O3, C, ZnO, ZrO2 and various TiO2 substrates. The catalysts were characterized by ICP, XRD and TGA‐H2 . For Co/TiO2 P25, the effects of passivation, aging (storage at room temperature), and in situ activation under H2 were investigated. The catalysts must be tested shortly after synthesis in order to prevent deactivation. Cobalt supported on TiO2 P25 was the most active and 69 % yield of 2‐octanone was obtained, using decane as a solvent. Selectivities for 2‐octanone were observed in the range of 90 % to 99.9 %. Small amounts of C16 compounds were also formed due to aldol condensation/dehydration reactions. The catalysts exhibited higher conversion in the dehydrogenation of secondary alcohols (65‐69 %), in comparison to primary alcohols (2–10 %). The dehydrogenation of 1, 2‐octanediol led to 1‐hydroxy‐2‐octanone, with a selectivity of 90 % and 69 % for Co/TiO2 P25 and Co/TiO2 P90, respectively. Abstract : Cobalt dehydrogenates : The acceptorless dehydrogenation of 2‐octanol was studied over a range of cobalt catalysts. Decane was shown to be the most adequate solvent. Cobalt supported on TiO2 P25 was the most active and 69 % yield of 2‐octanone was obtained. Long period of storage led to deactivation. The conversion strongly depended on the nature of the support. Also, the dehydrogenation of 1, 2‐octanediol was tested over Co catalysts. 1‐Hydroxy‐2‐octanone was the major product with a selectivity between 69 % and 90 %.