Preparation and evaluation of titanium silicalite-1 utilizing pretreated titanium dioxide as a titanium source

In this paper, TS-1 powder was prepared by utilizing pretreated titanium dioxide as titanium source. The structure and activity of the prepared catalysts were investigated by XRD, FT-IR, UV–vis and semicontinuous reaction of cyclohexanone ammoximation. The results showed that the prepared catalyst with pretreated titanium dioxide as a titanium source containing less Brönsted acidic sites than that of the standard sample using TBOT as titanium source. After the post-treatment by 0.5 M hydrochloric acid aqueous solution for removing the extra-framework Ti species, the obtained catalysts displayed almost the same catalytic activity under optimal condition as the titanium source of TBOT.

The results of cyclohexanone ammoximation catalyzed by TS-1 samples with different post-treated time: 1, 0 h; 2, 6 h; 3, 12 h; 4, 24 h; 5, standard sample. (a) Conversion; (b) yield; (c) selectivity. These figures conclude that the samples with TiO2 as titanium source have catalytic activity. Samples 1–4 has postponed the best results to 5.5 h because the post-treatment with 0.5 M HCl aqueous solution can remove the extra-framework Ti species effectively.Figure optionsDownload as PowerPoint slideResearch highlights
► We discovered pretreated TiO2 could be used to synthesize TS-1 with high titanium content.
► It contained less Brönsted acidic sites than that of the standard sample using TBOT as titanium source.
► We found the importance of post-treatment.
► The post-treatment with 0.5 M HCL can remove the extra-framework Ti species efficiently.
► The obtained catalysts displayed almost the same catalytic activity under optimal condition as the titanium source of TBOT.