Brønsted Acid Generation over Alumina-Supported Niobia by Calcination at 1173 K

Abstract

Alumina-supported niobium oxide promotes Friedel-Crafts reaction of benzyl alcohol and anisole effectively. The optimized condition of the catalyst was 16 wt% as Nb 2 O 5 and calcination temperature of 1173 K. The catalyst exhibits the Brønsted acidity despite calcination at such high temperatures.

Highly Active Mesoporous Nb–W Oxide Solid‐Acid Catalyst

“…The trend of Brønsted acid sites corresponded to the Friedel-Crafts alkylation rate, that is, the reaction was promoted by the Brønsted acid. [11] The acid properties of mesoporous Nb x W (10Àx) oxides were also evaluated by 31 P magic-angle spinning (MAS) NMR spectroscopy, using trimethylphosphine oxide (TMPO) as a probe molecule. As the 31 P chemical shifts of protonated TMPO (that is, TMPOH + ) tended to move downfield, higher chemical shift values indicate higher protonic acid strength.…”

Catalytic performance of surface modified-niobic acid

“…The surface of niobic acid generally exhibits a high acid strength, even in the presence of water, as long as it remains in an amorphous form [4]. Moreover, calcination or acid treatment makes its acid properties to be tuned in a certain manner [5]. Especially, the treatment with mineral acids has been reported to be effective in suppressing the crystallization of niobic acid and increasing its surface acidity as well [6].…”

Screening of Supports and Additives for Heteropoly Acid Catalysts for Friedel-Crafts Reaction by High-throughput Screening and Data Mining

“…Among the H-type zeolites, β zeolite has properties as an anticoking catalyst 3) . Other mesoporous materials such as SBA-1 4) and transition metal oxides are other known types of catalysts 5), 6) . The high-throughput screening (HTS) approach is useful to estimate the catalytic properties of new materials.…”