e-journal

Transition metal phosphide hydroprocessing catalysts: A review

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Abstract.
The diminishing quality of oil feedstocks coupled with increasingly more stringent environmental
regulations limiting the content of sulfur in transportation fuels have given rise to a need for improved
hydroprocessing technology. This review begins with a summary of the major improvements in
hydrodesulfurization (HDS) and hydrodenitrogenation (HDN) catalysts and processes that have been
reported in recent years. It then describes a new class of hydroprocessing catalysts, the transition metal
phosphides, which have emerged as a promising group of high-activity, stable catalysts. The phosphides
have physical properties resembling ceramics, so are strong and hard, yet retain electronic and magnetic
properties similar to metals. Their crystal structures are based on trigonal prisms, yet they do not form
layered structures like the sulfides. They display excellent performance in HDS and HDN, with the most
active phosphide, Ni2P, having activity surpassing that of promoted sulfides on the basis of sites titrated
by chemisorption (CO for the phosphides, O2 for the sulfides). In the HDS of difficult heteroaromatics like
4,6-dimethyldibenzothiophene Ni2P operates by the hydrogenation pathway, while in the HDN of
substituted nitrogen compounds like 2-methylpiperidine it carries out nucleophilic substitution. The
active sites for hydrogenation in Ni2P have a square pyramidal geometry, while those for direct
hydrodesulfurization have a tetrahedral geometry. Overall, Ni2P is a promising catalyst for deep HDS in
the presence of nitrogen and aromatic compounds.

Keywords:
Phosphides
Sulfides
Ni2P
HDS
HDN
Active site
EXAFS

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Informasi Detail

Judul Seri

Catalysis Today

No. Panggil

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Penerbit

London : Elsevier B.V.., 2009

Deskripsi Fisik

Catalysis Today 143 (2009) 94–107

Bahasa

English

ISBN/ISSN

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Klasifikasi

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Tipe Isi

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Tipe Media

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Tipe Pembawa

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Edisi

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Subjek

KIMIA

Info Detail Spesifik

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Pernyataan Tanggungjawab

agus

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