Synthesis of ZSM-5 coatings on stainless steel grids and their catalytic performance for partial oxidation of benzene by N2O

Abstract

The one step hydroxylation of benzene has been performed over structured catalytic bed made of ZSM-5 coatings grown by hydrothermal synthesis on stainless steel grids. The catalysts demonstrated a 97% selectivity towards phenol formation at benzene conversion of 11%. In addition of achieving the same reactivity as over the traditional zeolitic fixed beds, these new catalytic packings present several advantages gained from the special arrangement of the catalytic bed like low pressure drop, improved heat and mass transfer, and controlled hydrodynamics.

Synthesis of structured filamentous zeolite materials via ZSM-5 coatings of glass fibrous supports

“…Then, the tetraethyl orthosilicate (TEOS, 98%, Merck-Suchardt) was introduced under vigorous stirring. The molar ratio was as follows: TPA-OH:Si(OEt) 4 :NaAlO 2 :Na 2 O:H 2 O = 8.5:100:1:28:8000. Ageing and homogenization of the mixture took place during 2-3 h. The gel was afterwards poured in the autoclave and the procedure was performed as described above.…”

“…The procedure was similar to the one described previously, but without adding a silica source in the form of Si(OEt) 4 . In this case, the silica from the support filaments was partially converted into MFI-structure.…”

“…Structured zeolitic packing can be prepared via a binderless hydrothermal synthesis on metal grids [2][3][4] or ceramics [5]. In our previous publication [4], we tested the ZSM-5 coatings on metal grids for partial oxidation of benzene by N 2 O to phenol.…”

“…In our previous publication [4], we tested the ZSM-5 coatings on metal grids for partial oxidation of benzene by N 2 O to phenol. Under appropriate reaction conditions at benzene/N 2 O (B/N) ratios higher than 4, the selectivity to phenol up to 98% was achieved [4].…”

“…In our previous publication [4], we tested the ZSM-5 coatings on metal grids for partial oxidation of benzene by N 2 O to phenol. Under appropriate reaction conditions at benzene/N 2 O (B/N) ratios higher than 4, the selectivity to phenol up to 98% was achieved [4]. As metallic substrates are known to catalyze deep oxidation, the metal grid support must be completely covered by the zeolite layer, which is sometimes difficult to obtain and requires a multi-step synthesis.…”