e-journal

Quantification of enhanced acid site accessibility in hierarchical zeolites – The accessibility index

---

Abstract.
An accessibility index (ACI) was derived from infrared spectroscopy of substituted alkylpyridines with
different size (pyridine: 0.57 nm, 2,6-lutidine: 0.67 nm, and 2,4,6-collidine: 0.74 nm) over hierarchical
porous ZSM-5 crystals. The samples were prepared by selective silicon extraction of a commercial sample
in NaOH (desilication), and they contained different degrees of intracrystalline mesoporosity. Our results
demonstrate the enhanced accessibility of Brønsted acid sites in the hierarchical zeolites. For example, a
relatively bulky molecule such as collidine, which probes practically no acid site of the parent mediumpore
MFI structure, can access up to 40% of the acid sites in the mesoporous sample. The ACI is a powerful
tool to standardize acid site accessibility in zeolites, and can be used to rank the effectiveness of synthetic strategies to prepare hierarchical zeolites.

Keywords:
Accessibility index
Hierarchical zeolites
Desilication
Mesoporous crystals
Infrared spectroscopy
Alkylpyridines
Catalyst effectiveness

---

Ketersediaan

Tidak ada salinan data

Informasi Detail

Judul Seri

Journal of Catalysis

No. Panggil

-

Penerbit

London : Elsevier Inc.., 2009

Deskripsi Fisik

Journal of Catalysis 264 (2009) 11–14

Bahasa

English

ISBN/ISSN

00219517

Klasifikasi

-

Tipe Isi

-

Tipe Media

-

Tipe Pembawa

-

Edisi

-

Subjek

KIMIA

Info Detail Spesifik

-

Pernyataan Tanggungjawab

agus

Versi lain/terkait

Lampiran Berkas

Komentar

---

Anda harus masuk sebelum memberikan komentar