High-performance ring-opening catalysts based on iridium-containing zeolite Beta in the hydroconversion of decalin

Authors: Dominic Santi, Tobias Holl, Vincenzo Calemma, Jens Weitkamp

Abstract:
Decalin was converted in a flow-type reactor under a hydrogen pressure of 5.2 MPa on Ir/H,A-Beta zeolite catalysts, where A stands for an alkali metal cation. In one series of catalysts,the Ir content was 3 wt.%, and the nature of A was varied from lithium to cesium. In a second series, the iridium content in Ir/H,Cs-Beta was varied from 1 to 5 wt.%. On some of these catalysts, open-chain decanes (OCDs) were formed with unprecedented selectivities and yields of up to 47 and 44%, respectively. The term “High-Performance Ring-Opening Catalysts” (HIPEROCs) was defined. Evidence is presented for hydrogenolysis on the metal being the main ring-opening mechanism on HIPEROCs. The main function of the Brønsted-acid sites is a mild isomerization of six-membered into five-membered naphthenic rings which are much easier to open by hydrogenolysis. Valuable mechanistic information can be deduced from the carbon-number distributions and the naphthenes vs. alkanes content of the hydrocracked products (C_9-). 

Keywords:
Selective ring opening
Open-chain decanes
Ir/Beta
HIPEROCs
Bifunctional catalysis
Hydrogenolysis
Decalin

Published in: Applied catalysis A: General  (Volume 455, Pages 1-266, 30 March 2013)

Publisher: Elsevier

ISSN Information: 0926-860X

High-performance ring-opening catalysts based on iridium-containing zeolite Beta in the hydroconversion of decalin

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