Nobel Prize winners in catalysis

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Nobel Prize winners in catalysis
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Excerpts from Alfred Nobels will (1895)
.The capital shall be invested by my
executors in safe securities and shall
constitute a fund, the interest on which shall
be annually distributed in the form of prizes to
those who, during the preceding year, shall have
conferred the greatest benefit on mankind.
It is my express wish that in awarding the
prizes no consideration whatever shall be given
to the nationality of the candidates, so that
the most worthy shall receive the prize, whether
he be Scandinavian or not...
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Nobel Laureates in Catalysis, Surface Chemistry
and related fields
1909 Wilhelm Ostwald (b. 1853 - d. 1932) Leipzig
University, Leipzig, Germany "in recognition of
his work on catalysis and for his investigations
into the fundamental principles governing
chemical equilibria and rates of reaction
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1912 Paul Sabatier (b. 1854 - d. 1941) (Toulouse
University, France) "for his method of
hydrogenating organic compounds in the presence
of finely disintegrated metals whereby the
progress of organic chemistry has been greatly
advanced in recent years
1918 Fritz Haber (b. 1868 - d.
1934) Kaiser-Wilhelm-Institut (now
Fritz-Haber-Institut) für physikalische Chemie
und Electrochemie Berlin-Dahlem, Germany for
the synthesis of ammonia from its elements"
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1931 Carl Bosch (b 1874 d 1940) Heidelberg
Univ I.G. Farbenindustrie A.G., Germany
"in recognition of their contributions to the
invention and development of chemical high
pressure methods"
1931 Friedrich Bergius (b 1884
1949) Heidelberg Univ I.G. Farbenindustrie
A.G. Germany.
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1956 Sir Cyril Norman Hinshelwood (b. 1897 - d.
1967) University of Oxford, Oxford, United
Kingdom
"for their researches into the mechanism of
chemical reactions
1956 N.N.Semenov (b. 1896 - d. 1986) Institute
for Chemical Physics of the Academy of Sciences
of the USSR, Moscow, USSR
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1963 Karl Ziegler (b. 1898 - d.
1973) (Max-Planck-Institute for Carbon Research),
Mülheim/Ruhr, Germany
for their discoveries in the field of the
chemistry and technology of high polymers"
1963 Giulio Natta (b. 1903 - d. 1979) Institute
of Technology, Milan, Italy
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"for their work on chirally catalysed
hydrogenation reactions"
2001 William S. Knowles (b. 1917) St. Louis, Mo,
USA
2001 Ryoji Noyori (b 1938) Univ. of Nagoya,
Nagoya, Japan
2001 K. Barry Sharpless (b. 1941) The Scripps
Research Institute La Jolla, CA, USA
"for his work on chirally catalysed oxidation
reactions"
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Other noble laureates in related fields
1903 S. Arrhenius
1973 G. Wilkinson
1983 K. Fukui and R. Hoffmann
1986 J.C.Polanyi, D R Herschbach, Y.T.Lee "for
their contributions concerning the dynamics of
chemical elementary processes"
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Nobel Prize 2001 Enantioselective catalysis

• Our body contains only L-amino acids
• and D-Carbohydrates

? In drugs and biological products
stereospecificity is very important
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Biological effects of enantiomers
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Biological effects of enantiomers
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Fundamentals of enantiomers
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• Nomenclature for enantiomers
• Based on optical rotation (-) or ()
• Based on D-glucose ie. Derivability from
  glyceraldehyde (D) or (L)
• (Fischer)
• 3) Cahn-Ingold-Prelog convention

D (-) Phenylglycine R-configuration
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Cahn-Ingold-Prelog convention
Based on priority of arrangement of atoms or
groups at the stereogenic centre
Arrange a to d in order of decreasing priority, d
to point away from the observer- If order is
clockwise, then it is R isomer Priority is
determined by the atomic number of the group Cl
gt S gtF gt O gt C gt H For two substituents of the
same atomic number, priority established by next
attached atoms CH2Cl gt CH2OH gt CH2CH3 gt CH3
Double bond 2 single bonds CHCH2 gt CH2CH3
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• Two important methods for preparation of pure
  enatiomers
• Asymmetric synthesis
• Resolution (often by kinetic methods)

Quantification of enantiomer purity
Optical purity a/ao x 100 a optical
rotation of the mixture, ao optical rotation
of pure enantiomer Enantiomeric excess (ee) (for
R gt S) (R - S) / (R S) x 100 (Eg., If R
S 95 5 , then ee is 90)
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NOBEL PRIZE CHEMISTRY - 2007
"for their work on chirally catalysed
hydrogenation reactions"
2001 William S. Knowles (b. 1917) St. Louis, Mo,
USA
2001 Ryoji Noyori (b 1938) Univ. of Nagoya,
Nagoya, Japan
2001 K. Barry Sharpless (b. 1941) The Scripps
Research Institute La Jolla, CA, USA
"for his work on chirally catalysed oxidation
reactions"
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W.S.Knowles Asymmetric hydrogenation for L-Dopa
(for Parkinsons disease) synthesis
L-Dopa
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R.Noyori - Asymmetric hydrogenation
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K.B. Sharpless Asymmetric oxidation
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Many drugs are pure enatiomers only some are
directly made by asymmetric Synthesis /
catalysis
Takasago synthesis of (-)menthol
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Nobel Prize in Chemistry - 2007 Professor
Gerhard Ertl  for his studies of chemical
processes on solid surfaces
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Professor Gerhard Ertl 
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The Nobel Prize has been awarded to Prof. Ertl
for his research on solid (mostly metal)
surfaces carried out over more than 30 years.

• His research has lead a better understanding of
• Chemisorption of gases (H2, CO, O2, N2)
• on metal surfaces
• 2) Mechanism of NH3 synthesis
• 3) Understanding of oscillations in CO oxidation
• over metal surfaces

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• During the course of his research, he has made
• use of many surface characterization techniques
• Low Energy Electron Diffraction (LEED)
• Scanning Tunneling Microscopy (STM)
• UV-photoelectron spectroscopy (UPS)
• Photoelectron emission microscopy (PEEM)
• The award is also, in a way for the application
• of surface characterization tools to resolve
• industrial problems

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Ertls contributions to deriving a mechanism for
NH3 - Synthesis
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Heterogeneous Catalysis
K A e- Ea/RT (NH3decomposition on W) Ea(het)
40 kcal.mole-1 Ea(hom) 80 kcal.mole-1 khet/k
hom e40 2.4 x 1017
The catalytic effect arises from the adsorption
(chemisorption) of the reactants on the surface
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NH3 - Synthesis
At 298 K, ?Gf -3.86 kCal/mol The reaction is
thermodynamically favorable high conversion
possible At 700K, ?Gf 6.55 kCal/mol The
reaction is thermodynamically less favorable
low conversion Conversion decreases at
higher temperature and increases at higher
pressures
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The reaction will need the formation of N and H
atoms on the surface and their combination The
H - H bond (104 kCal/mole) is easy to break on
metal surfaces even at room temperature However,
the breaking of the NN bond (225 kCal/mole) is
not easy and is possible (if at all) only at high
temperatures (because Ea for dissociative
chemisorption is high on most catalysts) Hence,
commercially NH3 synthesis is carried out at
high temperatures The penalty is low conversion
at high temperatures So, high pressures are
used (250 atmosphere and 450?C over
Fe-catalysts)
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NH3 SYNTHESIS SCHEME
STEAM
Natural GAS
Primary / Secondary Steam reforming
Desulfurization
CO H2
S compounds removed
HT LT shift
200 300 atm. 450?C Fe-catalyst
For removal of ppm CO
CO2 H2
NH3 synthesis (Multiple beds)
Pure H2
CO2 removal
Methanator
CO2
Recyle
10 15 conv
NH3
NH3 separation
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Mittasch and co-workers tested more than 2500
different catalysts in 6500 experiments They
discovered that promoted reduced fused iron oxide
(Fe2O3) promoted with K, Al etc made a good
catalyst for NH3 synthesis at elevated
temperatures and pressures. The catalyst (after
improvements) is still used today Recently,
supported Ru catalysts have been put into
practice these operate at lower temp. and
press.
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Mechanism of ammonia synthesis Since the
discovery of ammonia synthesis by Fritz Haber
during 1905-1908, many researchers have tried to
unravel and prove the mechanism of this reaction.
In 1975 Paul Emmett stated The experimental
work of the past 50 years leads to the conclusion
that the rate determining step in ammonia
synthesis is the chemisorption of nitrogen. The
question, however, as to whether the nitrogen
species is molecular or atomic, is still not
conclusively resolved. Shortly after, Gerhard
Ertls group showed via the application of
surface science tools that the active species is
dissociatively adsorbed (atomic) nitrogen, which
is stepwise hydrogenated.
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Ertl showed through LEED and thermal desorption
studies that N2 was adsorbed as mostly as
molecular species on clean Fe-surfaces (Fe
110). He found that atomic (dissociative)
adsorption was possible only when the Fe surface
was promoted with K Ea for dissociative
chemisorption was decreased by K. The thermal
desorption spectrum obtained by him using a K-
Fe surface and commercial NH3 synthesis catalyst
were similar. He explained that K donates
electrons to the Fe and makes it electron rich
and capable of breaking the N-N bond He also
confirmed the experimental observations using
theoretical (DFT) calculations
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Mechanism of NH3 synthesis as proposed by Ertl
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G. Ertl, J. Mol. Catal. 54 (1989) 343
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Oscillation in CO oxidation
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One of the most intensively studied reactions in
Gerhard Ertls group has been CO oxidation. In
this process, a chemisorbed CO molecule reacts
with an also chemisorbed oxygen atom to form a
very weakly bound CO2 molecule that under
reaction conditions immediately leaves the
surface. In 1982, Gerhard Ertl and his group
reported kinetic oscillations (oscillating rate
of CO2 formation) in the course of CO oxidation
reactions on single crystal surfaces, a
phenomenon that had so far only been found in
commercial reactors (due to mass / heat transfer
effects). Ertl and his group developed a
microscopic model for such oscillations in a
series of publications.
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For the bare metal surfaces (100) and (111) there
is a surface reconstruction to reduce the surface
strain. However, CO adsorbs more strongly on
the unmodified surface and at a certain coverage
the difference in adsorption energy is sufficient
to cause a reversal of the surface
reconstruction. Similarly, oxygen is also more
chemisorbed on the reverted surfaces. Then the
rate of catalytic process increases leading to a
lower coverage and a possibility for a surface
reconstruction. This can in addition to an
oscillatory kinetics also lead to a spatial
organization on the surface with domains rich in
CO and O2 respectively. Illustrations of
adsorption patterns observed by PEEM illustrates
this
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Conversion
LEED spots
G. Ertl. Surface Science 299/300 (1994) 742
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Principle of LEED
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Research on adsorption of gases
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Concluding Remarks
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Thank You
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