Characterization and Catalytic Performance of Niobic Acid Dispersed over Titanium Silicalite

Table 3

The amount of the Brønsted and Lewis acid sites and the area under the peak at around 1490 cm−1 of the samples.

Sample	Brønsted, 𝜇mol/g	Lewis, 𝜇mol/g	Lewis added, 𝜇mol/g^(#)	Peak area at 1490, cm−2(∗)
TS-1 (1%)	0	30	—	0.14
3Nb/TS-1	18	48	18	0.46
10Nb/TS-1	47	63	33	0.52
20Nb/TS-1	66	72	42	0.93
NBO	0	0	—	0
NBA	101	145	—	1.75

^(#)Additional amount of the Lewis in the samples Nb/TS-1, calculated by deduction of Lewis acid in the samples Nb/TS-1 by sample TS-1.^(*)Area of the peak at around 1490 cm−1, characteristic for the mixture of Brønsted and Lewis acid sites.