Influence of TiO2/TS-1 Calcination on Hydroxylation of Phenol

Abstract

Titanium oxide (TiO 2) was impregnated on the surface of titanosilicate-1 (TiO 2 /TS-1) and used as catalyst for hydroxylation of phenol with hydrogen peroxide. Calcination was conducted at various temperatures (400, 500, 600 and 700°C) in order to observe the effect on the structure and physicochemical properties towards catalytic activity for producing hydroquinone. The structure and physicochemical properties of the TiO 2 /TS-1 catalyst were characterized by several techniques, such as X-ray diffraction (XRD), infrared spectroscopy, nitrogen adsorption, pyridine adsorption and hydrophilic measurement. The results show that by increasing the calcination temperature, the surface acidity of the catalyst was also increased. The TiO 2 /TS-1 catalyst calcined at 500 °C proved to be optimal for hydroquinone production, in which the anatase-rutile phase may be present dispersed on the MFI framework.

The epoxidation of diallyl ether to allyl-glycidyl ether over the TS-1 catalyst

“…The hydrogen peroxide decomposition is strongly dependent on the pH of the reaction mixtures and on the surface concentration of the hydroxyl groups of the catalytic material [11]. The improving of the efficiency of the hydrogen peroxide conversion can be done by: (1) addition of additives such as for example: CH 3 COOH, KHSO 4 , KH 2 PO 4 , KHF 2 , Na 2 SO 4 , NaHCO 3 , K 2 CO 3 , K 3 PO 4 , K 2 HPO 4 or KH 2 PO 4 [11], (2) slow addition of hydrogen peroxide [11][12][13], (3) choosing of the appropriate solvent for the epoxidation process-the most beneficial are methanol, acetonitrile and acetone [12,14,15] or co-solvent for example sulfolane [16], (4) increasing of the acidity of the catalyst by the addition of metal oxide for example of TiO 2 and utilization of the appropriate temperature of the calcination [17] and (5) the surface hydrophobization of mesoporous titanium silicates [18]. In this work, we would like to test the way of the improving of the efficiency of hydrogen peroxide conversion by addition the appropriate additive to the reaction mixture-KH 2 PO 4 .…”

Studies on Obtaining Diglycidyl Ether from Allyl-Glycidyl Ether over the Mesoporous Ti-SBA-15 Catalyst

“…Very low values of this function show that at the studied conditions the catalyst was very active in the ineffective decomposition of hydrogen peroxide to water and oxygen, which takes place at the active centres of Ti in the catalyst even at very low temperatures (the total conversion of hydrogen peroxide changed from 83-90 mol%). The ineffective decomposition of hydrogen peroxide over titanium silicate catalysts has been described in a great number of works [52][53][54][55][56][57], and this phenomenon is typical for these catalysts, for example, it was shown in the literature that titanium hydroperoxo species can decompose hydrogen peroxide molecules via formation of Ti-O* radical and hydroperoxo radical (HOO*) [52]. As the results presented in this work showed, the Ti-SBA-15 catalyst was very active in the decomposition of hydrogen peroxide.…”

“…The hydrogen peroxide decomposition is strongly dependent on the pH of the reaction mixtures and on the surface concentration of the hydroxyl groups of the catalytic material [52]. The improving of the [52]; (2) slow addition of hydrogen peroxide [52,55,57]; (3) choosing of the appropriate solvent for the epoxidation process -the most beneficial are methanol, acetonitrile, and acetone [44,54,55] or co-solvent, for example, sulfolane [59]; (4) increasing of the acidity of the catalyst by the addition of metal oxide, for example, of TiO 2 , and utilization of the appropriate temperature of the calcination [56]; and (5) the surface hydrophobization of mesoporous titanium silicates [46]. We would like to test in our future work some of the ways of improving the efficiency of hydrogen peroxide conversion: choosing the appropriate solvent, additives, and slow addition of hydrogen peroxide.…”

Kinetics Performance for Cadmium (II) Ion Adsorption using Mesoporous Silica Embedded with Iron Oxide

“…The difficulties of separation have been generated by small particle of mesoporous silica SBA-15 so its give impact for filtering the the absorbate from adsorbent. [29][30][31] This problem can be overcome by adding subtituents/metals that can help the separation process. Regeneration of SBA-15 as an adsorbent can be done by separating the adsorbate.…”