Nonconventional Catalytic Process for Ultimate ... - Saudi Aramco

Nonconventional Catalytic Process for Ultimate
Removal of Organic Sulfur-Containing
Compounds in Hydrocarbon Fractions
Authors: Dr. Farhan M. Al-Shahrani, Dr. Tiacun Xiao, Dr. Abdennour Bourane, Dr. Omer R. Koseoglu
and Prof. Malcolm L.H. Green
ABSTRACT
Heightened concerns for cleaner air results in more stringent
regulations on sulfur contents in transportation fuels that will
make desulfurization more and more important. This has
exerted strong pressure, not only on the refiners but also on
governments and legislators. The sulfur problem is becoming
more serious in general, particularly for diesel fuels, as the
regulated sulfur threshold is rising and will likely require a
virtually sulfur-free liquid fuel within a few years.
Although conventional hydrodesulfurization (HDS) is still
the preferred technology for producing the ultra clean fuels,
other nonconventional methods, such as oxidative, radiative,
extractive, membrane, adsorption, biodesulfurization and
ultrasonic approaches have also gained interest in recent years
due to the increased cost of revamping the existing lowpressure
hydrotreating units. Most of the alternative
technologies have not been shown to be economically viable
on a commercial scale. Oxidative desulfurization technology,
however, has progressed to the state where it is nearing
commercialization. Oxidation chemistry represents an
alternative route to diesel desulfurization that complements
HDS chemistry. The integration of an oxidative desulfurization
unit with a conventional hydrotreating unit can
improve the economics of these regulation driven projects
relative to current HDS technology.
Of the nonconventional approaches to reduce the sulfur
content in hydrocarbon fractions, such as adsorption,
extraction, ionic exchange, biodesuflurization and oxidation,
an oxidation desulfurization (ODS) catalytic system
composed of sodium tungstate dihydrate (Na2WO4), aqueous
hydrogen peroxide (30% H2O2) and acetic acid (CH3CO2H) has been found promising for deep removal of sulfur in
diesel. From a chemistry point of view, the sulfur compounds
are transferred to their corresponding sulfones, which can be
preferentially extracted by polar solvents. By using ODS, the
sulfur level in commercial diesel of 1,100 ppm has been
reduced to less than 39 ppm, which meets the latest stringent
environmental legislation enforcing the production of ultra
low sulfur diesel (ULSD) (< 50 ppm). This article also covers
some discussion about the ODS process itself and a proposed
reaction mechanism.
30 FALL 2009 SAUDI ARAMCO JOURNAL OF TECHNOLOGY
INTRODUCTION
Sulfur in transportation fuels remains a major source of SO x,
which contributes to a refinery’s catalyst fouling, corrosion,
air pollution and acid rain 1, 2 . Therefore, the threshold limit
for sulfur levels in gasoline and diesel has already been
regulated on a global level, including in Saudi Arabia, to less
than 50 ppm of weight (ppmw) over the next few years 1-4 .
The new environmental legislation puts both crude oil
producers and oil fraction refineries under tremendous
pressure to cope with the new regulations and to push for the
production of ultra low sulfur diesel (ULSD). One school of
thought is asking for certain revamping of the current
hydrotreatment facilities in most refineries, while the other is
on the side of exploring new technologies, which might
involve either minor additions or even major grass root
changes to the existing targeted facilities.
Removal of sulfur from organic sulfur compounds in liquid
fuels has long been achieved by hydrodesulfurizaion (HDS) using
a Co-Mo/Al 2O 3 or a Ni-Mo/Al 2O 3 catalyst in the temperature
range from 320 ºC to 360 ºC, and in the pressure range of 30
bar to 60 bar of H 2 partial pressure 4-6 . In this process, which
requires the presence of excess hydrogen, the sulfur atom is
hydrotreated to form mainly H 2S as shown in the reaction of
ethanethiol:
C 2H 5SH + H 2 ➛ C 2H 6 + H 2S
The H 2S evolved from the HDS is a toxic gas that needs
further treatment to form elemental sulfur, a useful non-toxic
yellow powder. According to its inventor, this process is called
the “Claus Process” in which the gaseous sulfur is
transformed into elemental sulfur (S 8). Solvent extraction
utilizing a solution of diethanolamine (DEA) dissolved in
water is applied to separate the hydrogen sulfide (H 2S) gas
from the process stream. In this process, the H 2S gas is
trapped or dissolved in the DEA by bubbling a hydrocarbon
gas stream containing H 2S through the DEA solution. In
general, conversion of the concentrated H 2S gas into sulfur
occurs in two stages:
1) Combustion of part of the H 2S stream in a furnace, producing
sulfur dioxide (SO 2), water (H 2O) and elemental sulfur (S):
2H 2S + 2O 2 ➛ SO 2 + S + 2H 2O

2) Reaction of the remainder of the H 2S with the
combustion products in the presence of a catalyst. The H 2S
reacts with the SO 2 to form sulfur:
2H 2S + SO 2 ➛ 3S + 2H 2O
As the reaction products are cooled, the sulfur drops out of
the reaction vessel in a molten state, which can be stored.
Sulfur-containing compounds that are typically present in
hydrocarbonaceous fuels include aliphatic molecules, such as
sulfides, disulfides and mercaptans, as well as aromatic
molecules, such as thiophene, benzothiophene (BT),
dibenzothiophene (DBT) and alkyl derivatives such as 4,6dimethyl-dibenzothiophene
(DMDBT). Those latter molecules
have a higher boiling point than the aliphatic ones and are
consequently more abundant in higher boiling fractions.
Conventional HDS technology can desulfurize aliphatic and
acyclic sulfur-containing organic compounds on an industrial
scale, as is the case in most refineries in the world. Aromatic
DBT, and especially 4,6-alkyl-substituted DBTs, are difficult to
convert to H 2S due to the sterically hindered nature of these
compounds on the catalyst surface 5-7 .
For this reason, the removal of the DBTs by HDS, to give the
desired low levels of sulfur in diesel, requires high temperature
and H 2 pressure conditions and subsequently a bigger reactor
size, as well as an active catalyst. From an environmental and
economic viewpoint, it is extremely desirable to develop an
alternative, more energy-efficient desulfurization process for the
production of virtually sulfur-free fuel.
Reported deep desulfurization processes include, but are
not limited to, selective adsorption 6 , extraction with ionic
liquids 7 , oxidative desulfurization (ODS) 8-11 , biodesulfurization
12, and other processes 13 . Due to a short reaction time
at ambient conditions, high efficiency and selectivity, ODS
combined with extraction is regarded to be among the
promising processes in this regard. In this process, sulfurcontaining
species like sulfides, BT, DBT and alkyl-related
derivatives are transformed into their corresponding
sulfoxides or sulfones species, which are then removed in a
second step.
Various studies on the ODS process have employed
different oxidizing agents, such as NO 2 14 tert-butyl
hydroxide 11 and H 2O 2 8-11 . Hydrogen peroxide is commonly
used as an oxidizing reagent due to its relatively low price,
environmental compatibility and commercial availability.
H 2O 2 is effective in the presence of a transition metal-based
catalyst and in acid media 8-11 . Examples of transition metalbased
systems are tungstophosphoric acid 8 , Na 2WO 4 +
[(n-C 4H 9)4N]Cl 15 , K 12WZnMn 2(ZnW 9O 34)2 + [CH 3(n-
C 8H 17)3N]Cl 16 , 2-NO 2C 6H 4SeO 2H 17 , hemoglobin 18 and other
transition metal-based oxides 1, 2, 13 .
Herein we describe a simple and highly effective catalytic
system for the oxidation of DBTs. The catalytic system was
evaluated for the removal of sulfur-containing compounds in
diesel 19-25 . Although, there is still room for improvement for
the catalyst and the process overall, which may have even
better results of less than 10 ppm sulfur.
OXIDATION OF MODEL SULFUR COMPOUNDS
The catalyst system for the oxidation reaction is composed
of sodium tungstate (Na 2WO 4, 0.2 g), acetic acid
(CH 3CO 2H, 5 mL) and hydrogen peroxide (30% H 2O 2/H 2O,
1 mL) as an oxidizing agent. In a round-bottom vessel, the
oxidation reaction was carried out with separate model
solutions of DBT and 4,6-DMDBT in octane (500 ppm S) at
temperatures of 30 °C, 50 °C, 70 °C and 90 °C.
In each run, the Na 2WO 4 catalyst was observed to dissolve
gradually in the mixture, forming first an emulsion and then
an opaque lower layer with time, Fig. 1.
The opaque emulsion lower layer was observed to transfer
gradually to form a white milk-like layer once the mixture
temperature reached 70 ºC. At this temperature, a biphasic
system was clearly observed, Fig. 2.
In this biphasic system, the upper layer is clear, and has
been proven to be the hydrocarbon layer (the octane). The
lower layer is aqueous and milk-like and contains mainly
water, acetic acid and some of the sulfones. Trace amounts of
sulfone were also observed in the upper layer and most
probably at the interface of both layers.
Throughout the reaction, stirring was continuous, and the
progress of the reaction was monitored periodically by
withdrawing 0.1 mL aliquots of the upper hydrocarbon layer
Fig. 1. The first formation of the emulsion mixture.
Fig. 2. Photo of the flask showing a biphasic system formation at 70 °C.
SAUDI ARAMCO JOURNAL OF TECHNOLOGY FALL 2009 31

of the reaction mixture for GC-FID and other sulfur
analysis. Similar quantities were also withdrawn from the
lower layer. Every sample was immersed immediately in
liquid nitrogen to suspend the oxidation reaction. Figure 3
shows the evolution of the chromatogram of DBT and 4,6-
DMDBT with the reaction temperature.
It is observed that both DBT and 4,6-DMDBT are oxidized
to the corresponding sulfones indicated as DBTO 2 and 4,6-
DMDBTO 2, respectively. It can also be observed that the
conversion of the sulfur compounds into sulfones increases
with temperature.
Figure 4 shows the conversion of the sulfur compounds as a
function of the temperature of the two model solutions after
their ODS treatment to prove the need (or otherwise) for the
sodium tungstate catalytic system. This conversion, at a
different reaction temperature, was calculated using the
normalized peak areas as obtained from the GC-FID
chromatograms.
Both DBT and 4,6-DMDBT reached their maximum full
conversion at 70 °C in less than an hour of reaction time. In
the absence of Na 2WO 4, using similar amounts of
H 2O 2/CH 3CO 2H, poor conversion was observed.
Shiraishi et al. 5 and Otsuki et al. 26 , have calculated the
electron densities of sulfur atoms for DBT and 4,6-DMDBT at
5.758 and 5.760, respectively. Such trends have been attributed
to two main factors: (a) reduced availability of the lone pair
electrons, and (b) steric strain in the reaction products.
Fig. 3. GC-FID chromatographs of model solutions upon ODS treatment.
Fig. 4. The influence of ODS catalytic system on sulfur conversion of DBT (º) and
4,6-DMDBT (*) at different temperatures.
32 FALL 2009 SAUDI ARAMCO JOURNAL OF TECHNOLOGY
It is worth mentioning that this new ODS catalytic system
efficiently reached full conversion of the sulfur compounds to
sulfones without the addition of a phase transfer agent (PTA).
Noyori et al. 27 , previously reported the use of Na 2WO 4 with
phosphoric acid and a quaternary ammonium salt promoter for
the oxidation of diphenyl sulfide to give the corresponding
sulfone. In the absence of the quaternary ammon ium salt PTA,
no oxidation was observed in their system.
OXIDATION OF A HYDROTREATED DIESEL
The new oxidation system was then tested on a commercial
diesel sample supplied by Rabigh Refinery. The diesel high
temperature (HT) boiling ranges of 250 °C - 350 °C has 1,100
ppm sulfur content. A selective sulfur detector, a pulse flame
photometric detector (PFPD), was especially useful to monitor
changes in the concentration of the different sulfur com -
pounds existing in the diesel. In a series of extensive tests at
various concentration levels of standard sulfur compounds,
the sensitivity, linearity, and accuracy of the technique as
applied to the range of sulfur compounds was established.
The chromatogram in Fig. 5 shows the analysis of the HT
diesel sample using GC-PFPD.
In this chromatogram, only the most abundant sulfur
compounds, according to their concentration, can be seen. A
BT Benzothiophene
(Internal Standard)
MEBT Methyl ethyl benzothiophene
DBT Dibenzothiophene
4-MDBT 4-Methyl dibenzothiophene
3-MDBT 3-Methyl dibenzothiophene
4,6-DMDBT 4,6-Dimethyl dibenzothiophene
1,4-DMDBT 1,4-Dimethyl dibenzothiophene
1,3-DMDBT 1,3-Dimethyl dibenzothiophene
Tri-MDBT Tri-methyl dibenzothiophene
Tri-EDBT Tri-ethyl dibenzothiophene
C3-DBT C3-Dibenzothiophene
Fig. 5. GC-PFPD chromatogram of the sulfur compounds in the HT diesel.

total of 79 different sulfur compounds were identified in this
diesel, with DBT and its alkyl derivatives being the major
sulfur compounds.
In this chromatogram, the higher intensity peaks of
compounds, such as 4,6-DMDBT, 4-MDBT and DBT were
assigned for comparison with the fingerprint of standard
samples analyzed under similar analytical conditions. The rest
of the peaks were compared to several publications in which
similar conditions and column specifications had been used.
It can be noted from the chromatogram that the presence of
DBT and its alkyls is predominant since conventional HDS
techniques are unable to remove these refractory sulfur
compounds. In these experiments, the BT was added as an
internal standard before injection in the GC-PFPD. The
known concentration was used to calculate the concentration
of other sulfur compounds.
The sulfur containing compounds in the diesel sample were
observed to be oxidized to their corresponding sulfones, and
these were further extracted with methanol, Fig. 6. The sulfur
concentration was successfully reduced by ODS and then by
extraction by more than 92% and 97%, respectively. In a
reaction time of less than an hour, the total sulfur content in the
treated diesel sample was reduced from 1,100 ppm to less than
39 ppm; this represents a total sulfur removal efficiency of 97%.
The catalyst was mainly recovered in the aqueous lower layer
and reused effectively for six consecutive new batches of ODS
processes, topping up the hydrogen peroxide intake each time.
DISCUSSION ABOUT THE ODS REACTION
Generally, in the ODS reactions, the divalent sulfur atom of the
organic sulfur compounds undergoes the electrophonic addition
of oxygen atoms from the hydrogen peroxide to form the
sulfone, i.e., hexavalent sulfur. The chemical and physical
properties of sulfones are significantly different from those of
fuel oil hydrocarbons. Therefore, they can be easily removed by
conventional separation methods, such as distillation, solvent
extraction, adsorption and decomposition 10-13 . Figure 7 is a
schematic diagram of the process of the overall ODS reaction.
Sulfur concentration (ppm)
100
80
60
40
20
0
BT
C 2H5
S
S
MEBT
CH 3
S
H 3C
S
H H3C 3C
S
H 3C
DBT
4MDBT
4,6 , DMDBT
H 3C
1,4-DMDBT
S
H 3C
Diesel
After ODS ODS
After extraction
Fig. 6. Changes in the concentration of the organic sulfur-containing compounds
in HT diesel after the ODS treatment that was followed by methanol extraction.
CH 3
1,3-DMDBT
CH 3
H 3C
S
H 3C
S
C 2H5
CH 3
C 2H5
S
C
C 3H7
2H5
TriMDBT
TriEDBT
C3DBT
S
DISCUSSION OF THE ODS MECHANISM
The tungstate-based catalyst has been shown effective for the
oxidation of the others into sulfones using H 2O 2 as the
oxidant in a two-liquid phase system together with a phase
transfer catalyst (PTC) 16-18 . Several mechanisms of ODS
reactions have been proposed previously 12, 13, 18 . The homo -
geneous biphasic ODS system described above is simple and
uses no PTA. Figure 8 is a detailed view of the reaction
mechanism.
Once the catalyst is mixed with the hydrogen peroxide and
the diesel fuel in acetic acid, the biphasic catalyst system starts
to form at room temperature. We suggest that WO 42-anion
reacts in two steps with two molecules of H 2O 2 in sequential
substitution reactions; in each step a W=O group is replaced
by a W (O 2) group and H 2O is displaced. The resulting
peroxotungstate [(-O)2 W (O 2)2] anion then reacts by
sequential oxygen atom transfer to the sulfur of R 2S to form
R 2SO (sulfoxide) then R 2SO 2 (sulfone), which can be
extracted in the aqueous phase. The peroxotungstate can be
regenerated on the interface between the two layers or in the
Fig. 7. The overall ODS reaction and a sketch of the biphasic system.
R 1
Na
W
+
Na +
O
O
O
VI
H
O
O
O
O
H
S
R 2
2H2O2
2H2O
Polar Phase
Fig. 8. Proposed ODS reaction mechanism.
R 1
R 1=Aryl/CH3 R2=Aryl/CH3
O O O
S
S
R 2
R 1 R 2
2 Oxygen atoms
transfer reaction
Na
Non polar Phase
W
+
Na +
O
O
Na
O
W
O
+ O
O
VI VI
O
O
O
+ Na O
2H 2O
two steps substitution
of O 2- by O 2 2-
2H 2O2
Na +
O
O
+ Na
VI
W
SAUDI ARAMCO JOURNAL OF TECHNOLOGY FALL 2009 33
H 2O
O
O
H
O
H
Sulfone Precipitate

Fig. 9. Raman spectra of STDH (Catalyst) and DBTSTDH (Product).
Conventional HDS
H2S
H 2
Diesel Feed
H
D
S
ODS Catalytic System
Fig. 10. General scheme of ODS process post HDS unit.
aqueous phase in the presence of an adequate supply of H 2O 2.
Sulfone is known to be slightly more polar than sulfur
compounds, so they will form a white precipitate. The whole
process will result in a biphasic solution in which the upper
layer becomes almost sulfur-free diesel.
The tungstate anion has the normal tetrahedral structure.
Figure 9 shows the Raman spectroscopy of the catalyst before
and after the ODS reaction.
The Raman stretching above 900 cm -1 is usually attributed to
the W=O stretching while the W-O bend vibration is around 320
cm -1 20-22 . The standard STDH has bands at 928 cm -1 , 890 cm -1 ,
836 cm -1 and 331 cm -1 in its ordinary tetrahedral struc ture. After
the ODS reaction, the new bands are seen at 970 cm -1 , 950 cm -1 ,
895 cm -1 and 312 cm -1 , which suggest the presence of different
forms or more than one peroxotungstate system.
The electrophilicity of the peroxotungstate intermediate is
much higher than that of H 2O 2 so it will participate effectively
in the oxidation of sulfur atoms. The ligation on the W center
would increase the reactivity of the peroxoligands, and the
metal center (W) has an unchanged oxidation number of VI
throughout the whole process. The sulfur compound in the
form of R 2S is nucleophilic due to the presence of two lone
pairs of electrons on the sulfur, which can be donated to form
bonds with oxygen from the peroxotungstate.
The tungstate catalyst is soluble in the acetic acid solution
and forms a biphasic catalyst system. The role of the acetic
acid in this reaction may be to increase the dispersion of the
catalyst and to promote and possibly to protonate oxo and
peroxo groups of the tungstate system 9-11, 14, 19, 25 .
34 FALL 2009 SAUDI ARAMCO JOURNAL OF TECHNOLOGY
O
D
S
Extraction
ULSD
Sulfones
CONCLUSION
We conclude that, at modest temperatures and under
atmospheric pressure, our ODS catalytic system, comprised of
Na 2WO 4 H 2O 2 and acetic acid, is effective for removing most
of the last few hundred ppm of HDS-persistent organic sulfurcontaining
compounds in diesel. Therefore, it can be envisaged
that an ODS unit would be added as a complementary post
treatment unit to the current HDS facilities, Fig. 10.
By achieving a sulfur content of less than 50 ppm in diesel,
the current ODS process, when combined with extraction, has
the potential to meet future environmental legislations 1-4 .
ACKNOWLEDGMENT
The authors wish to thank Saudi Aramco management for
their support and permission to present the information
contained in this article. We would also like to thank Dr.
Omer AbdulHamid, Mr. Khalil Al-Shafei, Dr. Bashir Al-
Dabbousi and Mr. Richard Horner from Saudi Aramco for
their fruitful discussions, directions and usual support. Thanks
also to Dr. Sami Barri for the diesel analysis in the Imperial
College. Many thanks as well to the management and
colleagues at the Inorganic Chemistry Laboratory at Oxford
University for their outstanding collaboration.
REFERENCES
1. Yang, R.T., Hernandez-Maldonado, A.J. and Yang, F.H.:
“Desulfurization of Transportation Fuels with Zeolites
under Ambient Conditions,” Science, Vol. 301, No. 5,629,
2003, pp. 79-81.
2. Gosling, C.D., Gembicki, V.A., Gatan, R.M., Cavanna, A.
and Molinari, D.: “The Role of Oxidative Desulfurization
in an Effective ULSD Strategy,” (UOP LLC), Chemindix,
Bahrain, 2004.
3. Turaga, U.T. and Choudhary, T.V.: “Desulfurization and Novel
Process for Removal of Sulfur from Hydrocarbons,”
(ConocoPhillips Company, USA), Application: WO, 2006, p. 31.
4. Berti, V. and Iannibello, A.: “Hydrodesulfurization of
Petroleum Residues: Principles and Applications,” 1975, p.
322.
5. Shiraishi, Y., et al.: “Desulfurization of Light Oil by
Reaction of Sulfur Compounds with Chloramine T
Resulting in Sulfimides Formation,” Chemical
Communications, Vol. 14, 2001, pp. 1,256-1,257.
6. McKinley, S.G. and Angelici, R.J.: “Deep Desulfurization
by Selective Adsorption of Dibenzothiophenes on Ag+/SBA-
15 and Ag+/SiO2,” Chemical Communications, Vol. 20,
2003, pp. 2,620-2,621.
7. Bosmann, A., et al.: “Deep Desulfurization of Diesel Fuel
by Extraction with Ionic Liquids,” Chemical
Communications, Vol. 23, 2003, pp. 2,494-2,495.

8. Yazu, K., Makino, M. and Ukegawa, K.: “Oxidative
Desulfurization of Diesel Oil with Hydrogen Peroxide in
the Presence of Acid Catalyst in Diesel Oil/Acetic Acid
Biphasic System,” Chemistry Letters, Vol. 33, No. 10,
2004, pp. 1,306-1307.
9. Campos-Martin, J.M., Capel-Sanchez, M.C. and Fierro,
J.L.G.: “Highly Efficient Deep Desulfurization of Fuels by
Chemical Oxidation,” Green Chemistry, Vol. 6, No. 11,
2004, pp. 557-562.
10. Garcia-Gutierrez, J.L., et al.: “Ultra-Deep Oxidative
Desulfurization of Diesel Fuel with H2O2 Catalyzed under
Mild Conditions by Polymolybdates Supported on
Al2O3,” Applied Catalysis, A: General, Vol. 305, No. 1,
2006, pp. 15-20.
11. Wang, D., et al., “Oxidative Desulfurization of Fuel Oil,
Part I. Oxidation of Dibenzothiophenes using Tert-Butyl
Hydroperoxide,” Applied Catalysis, A: General, Vol. 253,
No. 1, 2003, pp. 91-99.
12. Yu, B., et al.: “Deep Desulfurization of Diesel Oil and
Crude Oils by a Newly Isolated Rhodococcus
Erythropolis Strain,” Applied and Environmental
Microbiology, Vol. 72, No. 1, 2006, pp. 54-58.
13. Song, C. and Ma, X.: “New Design Approaches to Ultra-
Clean Diesel Fuels by Deep Desulfurization and Deep
Dearomatization,” Applied Catalysis, B: Environmental,
Vol. 41, Nos. 1-2, 2003, pp. 207-238.
14. Tam, P.S., Kittrell, J.R. and Eldridge, J.W.:
“Desulfurization of Fuel Oil by Oxidation and
Extraction. Part 1. Enhancement of Extraction Oil Yield,”
Industrial & Engineering Chemistry Research, Vol. 29,
No. 3, 1990, pp. 321-324.
15. Stec, Z., et al.: “Oxidation of Sulfides with H2O2 Catalyzed by Na2WO4 under Phase-Transfer Conditions,”
Polish Journal of Chemistry, Vol. 70, No. 9, 1996, pp.
1,121-1,123.
16. Neumann, R. and Juwiler, D.: “Oxidations with
Hydrogen Peroxide Catalyzed by the
[WZnMn(II)2(ZnW9O34)2]12- Polyoxometalate,”
Tetrahedron, Vol. 52, No. 26, 1996, pp. 8,781-8,788.
17. Reich, H.J., Chow, F. and Peake, S.L.: “Seleninic Acids
as Catalysts for Oxidations of Olefins and Sulfides using
Hydrogen Peroxide,” Synthesis, Vol. 4, 1978, pp. 299-301.
18. Klyachko, N.L. and Klibanov, A.M.: “Oxidation of
Dibenzothiophene Catalyzed by Hemoglobin and other
Hemoproteins in Various Aqueous-Organic Media,”
Applied Biochemistry and Biotechnology, Vol. 37,
No. 1, 1992, pp. 53-68.
19. Xiao, T., Shi, H., Al-Shahrani, F.M. and Green, M.:
“Hydrocarbon Recovery from Sulfones Formed by
Oxidative Desulfurization (ODS) Process,” paper IP244-
561539, April 20, 2008.
20. Al-Shahrani, F.M., Xiao, T., Martinie, G. and Green, M.:
“Catalytic Process for Deep Oxidative Desulfurization of
Liquid Transportation Fuels,” WO 2007103440, U.S.
Pat. Appl. Publ. 2007, 35 pp.
21. Martinie, G.M., Al-Shahrani, F.M. and Dabbousi, B.O.:
“Diesel Oil Desulfurization by Oxidation and
Extraction,” U.S. 2007051667, U.S. Pat. Appl. Publ.
2007, 9 pp.
22. Martinie, G.D., Al-Shahrani, F.M. and Dabbousi, B.O.:
“Process for Treating a Sulfur-Containing Spent Caustic
Refinery Stream using a Membrane Electrolyzer Powered
by a Fuel Cell,” U.S. 2006254930, U.S. Pat. Appl. Publ.
2006, 12 pp.
23. Martinie, G.D. and Al-Shahrani, F.M.: “Reactive Extrac -
tion of Sulfur Compounds from Hydrocarbon Streams,”
WO 2005066313, PCT Int. Appl. 2005, 24 pp.
24. Al-Shahrani, F.M., Xiao, T., Llewellyn, S., et al.:
“Desulfurization of Diesel via the H2O2 Oxidation of
Aromatic Sulfides to Sulfones using a Tungstate
Catalyst,“ Journal of Applied Catalysis, B:
Environmental, Vol. 73, 2007, pp. 311-316.
25. Al Shahrani, F.M.: “Oxidative Desulfurization of Diesel
Fuels,” Ph.D. thesis, 2008, University of Oxford Press,
Oxford, UK.
26. Otsuki, S., Nonaka, T., Takashima, N., et al.: Energy
Fuels, Vol. 14, 2000, p. 1,232.
27. Noyori, R., Aoki, M. and Sato, K.: “Green Oxidation
with Aqueous Hydrogen Peroxide,” Chemical
Communications, Vol. 16, 2003, pp. 1,977-1,986.
SAUDI ARAMCO JOURNAL OF TECHNOLOGY FALL 2009 35

BIOGRAPHIES
Dr. Farhan M. Al-Shahrani rejoined
Saudi Aramco’s Research and
Development Center (R&DC) in
August 2008 after his successful
completion of a 4 year advanced
degree program at the University of
Oxford, Oxford, UK.
Farhan first joined Saudi Aramco in 1993 in the College
Degree Program Non-Employee (CDPNE) program. In
1998 he received a third honor B.S. degree in Industrial
Chemistry from King Fahd University of Petroleum and
Minerals (KFUPM), Dhahran, Saudi Arabia. Since that
time, he joined the R&DC and worked in various units,
including advanced instrument, crude evaluation, process,
geochemistry and the environmental unit. In 2003, Farhan
received his M.S. degree in Chemistry, also from KFUPM
as a second honor.
Under the supervision of Prof. Malcolm L.H. Green,
Farhan’s Ph.D. thesis research focused on oxidative desulfurization
of diesel fuels, which resulted in the filing of two
international patents. To date, he has five registered patents
and more than 12 peer-reviewed papers.
While in Oxford, Farhan was able to launch a Saudi
Oxford Society that he voluntarily led for two consecutive
years. Moreover, he worked as the chairperson of the
scientific committee for the 2 nd International Saudi
Innovation Conference hosted last June by the University of
Leeds. Farhan is a member of the American Chemical
Society (ACS) and the prestigious Royal Society of
Chemistry (RSC).
Dr. Tiacun Xiao earned his Ph.D.
degree in Heterogeneous Catalysis
from the Chinese Academy of Science,
Beijing, China in 1993. As an
Associate Professor at Shandong
University in China, he spent the next
6 years collaborating on both
petrochemical and environmental projects with Sinopec, the
Shandong Provincial Government and the World Bank. In
1999, Tiacun went to Oxford University and joined Prof.
Malcolm Green's Wolfson Catalysis Center as a Royal
Society BP Amoco Research Fellow. Since then, he has been
appointed a Visiting Professor at the Beijing University of
Chemical Technology, Beijing, China, a Lecturing Professor
at the Eastern China University of Science and Technology,
Shanghai, China and a Guest Professor at the Guizhou
University, Guiyang, China. He has published over 100
papers on catalysis, filed seven patents and received many
awards for his research both in China and in the UK.
Recently and jointly with Prof. Green, Tiacun was able
to launch the Oxford Catalysis Group as a new spin-off
company of the University of Oxford.
36 FALL 2009 SAUDI ARAMCO JOURNAL OF TECHNOLOGY
Dr. Abdennour Bourane is a Research
Scientist at the Research and
Development Center (R&DC). He is
leading activities within the Clean
Fuels project of the Downstream and
Strategic Program. Prior to joining
Saudi Aramco he worked at the
Institute of Research on Catalysis and Environment at Lyon
(IRCELyon), France and at the Chemical Engineering
Department of Kansas State University, Manhattan, KS.
Abdennour has more than 20 publications in international
peer-reviewed journals.
Abdennour received his Ph.D. degree in Chemistry from
the University of Lyon, Lyon, France.
Dr. Omer R. Koseoglu is a Research
Science Consultant at the Research and
Development Center (R&DC). He is
leading the Clean Petroleum Fuels
project of the Downstream and
Strategic Program.
Omer has a Ph.D. degree in
Chemical Engineering from the University of Toronto,
Toronto, Ontario, Canada; a M.S. degree in Chemistry
from Brock University, St. Catharines, Ontario, Canada;
and a B.S. degree in Chemical Engineering from Gazi
University, Ankara, Turkey. Prior to joining Saudi
Aramco, he worked for CONOCO, Inc. at the
Technology Development Center in Ponca City, OK, IFP
North America/Hydrocarbon Research, Inc. (HRI); and
Shell Canada Limited at the Oakville Research Center.
Omer has numerous publications and is a registered
professional engineer.
Professor Malcolm L.H. Green was
Professor and Head of Inorganic
Chemistry at Oxford University from
1989-2003. He then became an
Emeritus Research Professor. Malcolm
is also the co-founder of the Oxford
Catalysis Group.
He received a B.S. and Ph.D. degree from London
University, London, UK, the latter in 1959. Malcolm
carried out research at Cambridge University and then at
Oxford University in organotransition metal chemistry,
homogeneous and heterogeneous catalysis and, more
recently, the chemistry of carbon nanotubes. He has over
700 publications and was elected Fellow of the Royal
Society of Chemistry in 1985.