Design And Catalytic Application Of New Type Of Column Zirconium Phosphate

Layered metal phosphates, among numerous layered materials, have received considerable attention because of unique properties which lend themselves to various potential practical uses. Layered zirconium phosphate material is one of the typical layered phosphate materials. It is deemed as a kind of potential material in catalytic field for its thermal stablility of the layers and anti-acid properties, and its structure and catalysis site being designable. In spite of the considerable effort devoted to the design of layered phosphate materials, exploring new experimental synthesis route and applications in catalytic field is necessary. In this work, a mesoporous layered zirconium phosphate material was synthesized by a novel co-template method of using of a surfactant expanded zirconium phosphate for the formation of silica galleries into the interlayer space. And the catalytic active sites were introduced on the materials during the hydrolyzing process by co-condensation. This new kind of layered zirconium phosphate was expected to be a good solid acid catalyst in liquid reaction with its mesoporous structure, which is related to easy diffusion and access of large molecules to the active sites, and its designable active sites. We systematically studied surface modification of the silica-pillared layered zirconium phosphate, the synthesis of zirconia-pillared and titania-pillared layered zirconium phosphate and applied as catalyst in alkylation of hydroquinone with tert-butanol reaction, Prins condensation of β-pinene with paraformaldehyde and the selective catalytic reduction of NO with ammonia. The main results of the work are as follows:1. The proton in the silica-pillared layered zirconium phosphate was exchanged by different valence state of ions to modify the acid sites of the catalyst. And the ion-exchanged catalysts preserved or increased Lewis acid sites on the surface and eliminated Bronsted acid sites, especially, Lewis acid sites of catalyst Zn-ZrP increased most. The selectivity towards Nopol on the ion-exchanged catalysts improved in Prins condensation and it was found that Lewis acid sites influenced its catalytic performance a lot in condensation. Zn-ZrP showed best catalytic performance with85.4%conversion and58.5%yield under80℃for4h, and the reuse ability of Zn-ZrP was good. We synthesized the PhSO32-functionalized corresponding materials to increase the strength of acid. Chemical vapor synthesis and liquid method were used to synthesize PhSO32-functionalized pillared zirconium phosphates, respectively. The structure of the two kinds of materials was characterized and it found that the textural properties of G-ZrP-PhSO3H were better than that of L-ZrP-PhSO3H. And catalytic performance of G-ZrP-PhSO3H was more excellent that of L-ZrP-PhSO3H in alkylation of hydroquinone with tert-butanol reaction. The amount of accessible acid sites was positive related to the catalytic performance of the catalysts.2. zirconia-pillared and titania-pillared layered zirconium phosphates were synthesized. The textural properties and catalytic activity of the catalysts which were prepared in aqueous and alcohol media were researched and the results indicated the samples prepared in propanol were better as catalysts than in aqueous medium. Zirconia-pillared layered zirconium phosphates synthesized in propanol were applied in Prins condensation of β-pinene with paraformaldehyde and Na-ZrO2-ZrP-a-350showed best catalytic performance with87%selectivity and75%yield, and the reuse ability of Na-ZrO2-ZrP-a-350was good and the catalytic activity was recovered mostly after recalcination. The activities of the catalysts poisoned by DTBPy proved the amount of Lewis acid sites as well as proper L/B ratio played an important role in Nopol production through condensation. And then the activity and the selectivity of titania-pillared layered zirconium phosphates in condensation were not as good as that of the zirconia-pillared layered zirconium phosphates, which was mainly because the acidity of zirconia was superior to titania.3. Titania-pillared layered zirconium phosphate prepared in propanol was applied as support and supported copper to catalyze the selective catalytic reduction of NO with ammonia. It was found that the amount of supported copper and the calcination temperature influenced its catalytic performance a lot. Cu10ZrP(TiO2)-350showed best catalytic performance and the activity was nearly100%at225℃and maintain till375℃.