Type Material H₁.₂[Al₁.₁₇Ti₁.₂₃Si₉₃.₆O₁₉₂] : w H₂O

Method G. Ovejero, R. Van Grieken, M. A. Uguina, D. P. Serrano, J. A. Melero [1]

Batch Composition 1 TiO₂ : 0.25 Al₂O₃ : 40 SiO₂ : 216 H₂O : 7.44 (TPA)OH (TPA tetra-n-propylammonium) ^a

tetraethylorthosilicate [Alfa, Si(OC₂H₅)₄]
hydrochloric acid (0.2 N) (reagent grade)
isopropyl alcohol for analysis (Panreac)
aluminum isopropoxide, [Aldrich, Al(OC₃H₇)₃]
tetrapropylammonium hydroxide (TPAOH) [Alfa, 40 wt% (C₃H₇)₄NOH in water]
titanium tetrabutoxide [Alfa, Ti(OC₄H₉)₄]

Batch preparation (for 2.9 g dried cogel)

(1) [8 g tetraethylorthosiicate + 5 g hydrochloric acid (0.2 N)], mix at room temperature for 45 minutes
(2) [2.5 g isopropyl alcohol + 0.098 g aluminum isopropoxide], mix until dissolved
(3) [(1) + (2)], add (2) to (1) dropwise. Mix at room temperature for 45 minutes.
(4) [4 g TPAOH (40 wt%) +4 g H₂O], mix
(5) [(3) + 0.75 g (4)], add 20 wt% TPAOH slowly at room temperature. Stir at 0⁰C for 15 minutes
(6) [0.327 g titanium tetrabutoxide + 2 g isopropyl alcohol], mix until homogeneous
(7) [(5) + (6)], add (6) to (5) slowly at 0⁰C. Stir at 0⁰C for an additional 20 minutes

(8) [(7) + approximately 1.9 g (4)], add 20 wt% TPAOH slowly at room temperature; mix until gelation
(9) Dry overnight at 110âC to remove alcohol and water. Grind to give a powdered material
(10) [(9) + approximately 4.6 g (4)], impregnate the dried and powdered cogel to incipient wetness with 20 wt% TPAOH. Charge to autoclaves

Vessel: Teflon-lined autoclaves (50 mL)
Time: 24 hours
Temperature: 170⁰C
Agitation: none

(1) Centrifuge to recover crystalline product; wash with double-distilled water (three times)
(2) Dry overnight at 110⁰C
(3) Calcme in air at 550⁰C (heating rate 5⁰C/minutes and hold at 550⁰C for 5 hours)
(4) Yield; 95% on SiO₂

[1] G. Ovejero, R Van Grieken, M. A. Uguina, D. P. Serrano, J. A. Melero, Catal. Lett. 41(1996) 69
[2] G. Bellussi, A. Carati, M. G. Clerici, A. Esposito, Stud. Surf. 56. Catal. 63 (1991) 421
[3] L Forni, M. Pellozi, A. Giusti, G. Fornasari, R Milhini, J. Catal. 122 (1990) 44
[4] A. Thangaraj, R. Kumar, S. Sivasanker, Zeolites 12 (1992) 135
[5] D. Trong On, S. Kaliaguine, L Bonneviot, J. Catal. 157 (1995) 235
[6] F. Geobaldo, S. Bordiga, A Zecchina, E Gianello, G. Leofanti, G. Petrini, Catal. Lett. 16 (1992)109

a. Ti and trivalent metal ions, Al⁺³, Ga⁺³, Fe⁺³ and B⁺³, can be co-incorporated into ZSM-5 by conventional methods based on hydrothermal crystallization of a liquid gel obtained from respective alkoxides hydrolyzed in basic medium. [2-5]

b. By DR UV-VIS, adsorption around 330 nm is not detected either in the sample or in the cogel, showing the absence of bulk TiO₂ phases. [6]

c. By ²⁹Si and ²⁷A1 MAS-NMR, atoms are located in tetrahedral environments in the starting cogel and in the synthesized sample.