English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

Two steps transformation of (+)-citronellal, cyclization and hydrogenation, on ZnBr2/γ-Al2O3 and Ni/γ-Al2O3 catalyst have been realized with the selectivity to cyclization products (isopulegols) was very high (yield up to ~92.58%) over ZnBr2/γ-Al2O3 under mild condition (90 °C and 1 atm nitrogen atmosphere) with high Bronsted acid concentration, while at the same time very low cyclization rates were achieved over Ni/γ-Al2O3 with low or no Bronsted acidity, respectively. The highest cyclization rates were observed over Ni/ZnBr2/γ-Al2O3 under mild condition (90 °C and 1 atm hydrogen atmosphere). The second step transformation towards cyclization products, hydrogenation to menthols, was performed with Ni/γ-Al2O3 under hydrogen atmosphere. Surprisingly the one-step transformation of (+)-citronellal into menthols was investigated over Ni/γ-Al2O3 with yield ~84% under hydrogen atmosphere (90 °C, 1 atm) by exploiting the presence of acidic and hydrogenation sites on the catalyst surface. On the Ni/γ-Al2O3 catalyst it was found that the cyclization of (+)-citronellal to isopulegols occurs on the surface of the support. In the presence of the noble metal, the isopulegols are further hydrogenated to the menthols.

indonesian journal of chemistry

CYCLIZATION AND HYDROGENATION OF (+)-CITRONELLAL TO MENTHOLS OVER ZnBr&lt;sub&gt;2&lt;/sub&gt; AND Ni CATALYSTS SUPPORTED ON γ-Al&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt;