Study of the tungstated alumina catalysts deactivation in the process of sorbitol hydrodeoxygenation and their regeneration efficiency evaluation

An Efficient Acetalization Method for Biomass‐Derived Furfural with Ethanol Using γ‐Al2O3‐Supported Catalysts

“…Acidity measurements through NPA desorption by TGA was performed to all catalytic materials (Figure ). These experiments give an estimation of the acid sites number and strength but do not allow differentiating Brønsted and Lewis acid sites . All desorption profiles (Figure ), except for γ‐Al 2 O 3 , contain a large peak of NPA desorption before 350 °C attributed to weak acid sites (Figure ).…”

“…NPA desorption after 350 °C is attributed to stronger acid sites. The concentration of these strong acid sites per gram of catalyst in the range [350–550 °C] gives the following decreasing ranking: γ‐Al 2 O 3 > Ni 1.5 Rh 1.5 /γ‐Al 2 O 3 > Rh 3 /γ‐Al 2 O 3 >. Different acidity profiles appear: (i) Ni 3 /γ‐Al 2 O 3 , Ni 1.5 Rh 1.5 /γ‐Al 2 O 3 and Rh 3 /γ‐Al 2 O 3 contain a majority of weak acid sites and few very strong acid sites, (ii) Ni 1.5 Rh 1.5 /γ‐Al 2 O 3 , Rh 3 /γ‐Al 2 O 3 and Ni 3 /γ‐Al 2 O 3 have fewer weak acid sites and (iii) γ‐Al 2 O 3 contains the largest amount of strong and very strong acid sites.…”