Issue 17, 2017

Simple quantification of zeolite acid site density by reactive gas chromatography

Abstract

The Brønsted acid site densities of ZSM-5, BEA and single unit cell self-pillared pentasil (SPP) zeolites of varying Si/Al ratios were measured using a new technique, reactive gas chromatography (RGC), which utilizes alkylamine decomposition to selectively count Brønsted acid sites. Reactive gas chromatography condenses the conventional temperature-programmed desorption mass spectrometer (TPD-MS) setup into a single, fully-automated gas chromatograph (GC). Alkylamine decomposition reactions were conducted in a microcatalytic reactor placed within a temperature-controlled GC inlet liner. Products were then separated in a GC column and quantified with a flame ionization detector. A comparison between reactive gas chromatography measurements and conventional temperature programmed desorption methods showed agreement; RGC acid site density measurements were further confirmed by comparison with in situ pyridine titration of isopropanol dehydration. Reactive gas chromatography measurements performed using multiple alkylamines, were found to yield identical Brønsted acid site densities. The method of reactive gas chromatography was found to be highly sensitive, where siliceous materials with Brønsted acid site densities as low as ∼1.0 μmol gcat−1 could be reliably measured.

Graphical abstract: Simple quantification of zeolite acid site density by reactive gas chromatography

Supplementary files

Article information

Article type
Paper
Submitted
26 May 2017
Accepted
05 Aug 2017
First published
07 Aug 2017

Catal. Sci. Technol., 2017,7, 3831-3841

Simple quantification of zeolite acid site density by reactive gas chromatography

O. A. Abdelrahman, K. P. Vinter, L. Ren, D. Xu, R. J. Gorte, M. Tsapatsis and P. J. Dauenhauer, Catal. Sci. Technol., 2017, 7, 3831 DOI: 10.1039/C7CY01068K

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements