Selective vapour-phase [alpha]-pinene isomerization to camphene over gold-on-alumina catalyst

• Published in: Applied catalysis. A, General Vol. 385; no. 1-2; pp. 136 - 143
• Main Authors: Simakova, IL, Solkina, YuS, Moroz, B L, Simakova, O A, Reshetnikov, SI, Prosvirin, I P, Bukhtiyarov, VI, Parmon, V N, Murzin, DYu
• Format: Journal Article
• Language: English
• Published: 15.09.2010
• Subjects: Catalysts; Coke; Conversion; Deactivation; Deposition; Gold; Isomerization; Titanium dioxide
• ISSN: 0926-860X
• DOI: 10.1016/j.apcata.2010.07.002

The vapour-phase isomerization of [alpha]-pinene for the first time was studied over a supported Au catalyst. [alpha]-pinene was isomerized to camphene over the 2.2% Au/[gamma]-Al sub(2O) sub(3) catalyst at 463-483 K using a solution of the reagent in n-octane as the initial reaction mixture and H sub(2 or N) sub(2) as a carrier gas. Under these conditions, the selectivity to camphene reaches 60-80% at 99.9% conversion of [alpha]-pinene. The reaction is found to be first-order with respect to [alpha]-pinene, the apparent activation energy being similar to that observed with the conventional TiO sub(2 catalyst. The prominent catalyst deactivation has been observed at increased [alpha]-pinene concentrations in the inlet reaction mixture (>=4 vol% in n-octane solution). According to HRTEM and TPO results, the deactivated catalyst contains the carbonaceous deposits that may block the catalyst surface. Almost complete regeneration was done in flowing O) sub(2) at temperature up to 923 K required to totally eliminate the coke deposits.