Effects of Novel Supports on the Physical and Catalytic Properties of Tungstophosphoric Acid for Alcohol Dehydration Reactions

Abstract

The catalytic behavior of tungstophosphoric acid supported on modified mesoporous silica materials for the dehydration of 2-butanol and methanol was studied. Specifically, the supports evaluated here consisted of unmodified MCM-41 and SBA-15 mesoporous silicas, and these materials coated with sub-monolayer quantities of alumina, titania, and zirconia. UV-Vis DRS and 31 P-NMR spectroscopy showed that the tungstophosphoric acid species retained their chemical identity in the synthesized supported form, although the spectra were influenced by the specific support material used. In addition, their acidic properties were evaluated using temperature-programmed oxidation of isopropyl amine. The differences in reaction rates between the samples reflect both the diversity in the amount of Brønsted acidic sites available for catalysis and dissimilarities in coking resistance. These two characteristics depend, in turn, on the type of support modifier used to prepare the catalyst.

Dimethyl Ether Synthesis over Novel Silicotungstic Acid Incorporated Nanostructured Catalysts

“…Calcination of the synthesized material at 400ºC caused an increase in the pore volume (Table 1). As stated by Herrera et al (2008) and also as reported in our earlier publications (Ciftci et al, 2010;, presence of Brønsted acid sites is the major indication of the activity of the catalysts in alcohol dehydration reactions. 5).…”

Hydrodeoxygenation of the Angelica Lactone Dimer, a Cellulose‐Based Feedstock: Simple, High‐Yield Synthesis of Branched C7–C10 Gasoline‐like Hydrocarbons

“…Since the dehydration of the intermediate alcohols was apparently not efficient enough, we replaced the g-Al 2 O 3 with phosphotungstic acid (H 3 W 12 O 40 P) loaded on mesoporous silica (MCM-41), which is known to dehydrate aliphatic alcohols under even milder conditions than g-Al 2 O 3 . [36] When a combination of Cu-ZnO/Al 2 O 3 and HPW/MCM-41 was employed, the total yield of hydrocarbons improved to 68 %.…”

Hydrodeoxygenation of the Angelica Lactone Dimer, a Cellulose‐Based Feedstock: Simple, High‐Yield Synthesis of Branched C7–C10 Gasoline‐like Hydrocarbons

“…Analysis of the reaction mixture showed a 41 % yield of C 7 –C 10 hydrocarbons alongside a considerable quantity of alcohol and ether products. Since the dehydration of the intermediate alcohols was apparently not efficient enough, we replaced the γ‐Al 2 O 3 with phosphotungstic acid (H 3 W 12 O 40 P) loaded on mesoporous silica (MCM‐41), which is known to dehydrate aliphatic alcohols under even milder conditions than γ‐Al 2 O 3 36. When a combination of Cu‐ZnO/Al 2 O 3 and HPW/MCM‐41 was employed, the total yield of hydrocarbons improved to 68 %.…”