|
Combinatorial Chemistry &
High Throughput Screening
ISSN: 1386-2073
Combinatorial Chemistry &
High Throughput Screening
Volume 10, Number 2, February 2007
Contents
Combinatorial Heterogeneous Catalysis (Part 2)
Guest Editor: József L. Margitfalvi
Editorial Pp.
83-84
Development of an Integrated Informatics Toolbox:
HT Kinetic and Virtual Screening Pp. 85-97
David Farrusseng, Frédéric Clerc, Claude
Mirodatos, Nabeel Azam, Francois Gilardoni, Joris W. Thybaut,
Periyasamy Balasubramaniam and Guy B. Marin
[Abstract]
Combinatorial Computational Chemistry Approach for
Materials Design: Applications in deNOx Catalysis, Fischer-Tropsch
Synthesis, Lanthanoid Complex, and Lithium Ion Secondary Battery
Pp. 99-110
Michihisa Koyama, Hideyuki Tsuboi, Akira Endou, Hiromitsu
Takaba, Momoji Kubo, Carlos A. Del Carpio and Akira Miyamoto
[Abstract]
High-Throughput Nanoparticle Catalysis: Partial Oxidation
of Propylene Pp. 111-119
Shici Duan, Michael Kahn and Selim Senkan
[Abstract]
Assessment of Predictive Ability of Artificial Neural
Networks Using Holographic Mapping Pp. 121-134
András Tompos, Lajos Végvári, Erno
Tfirst and József L. Margitfalvi
[Abstract]
Discovery of Novel Catalytic Materials for Emissions
Control Using High Throughput Scanning Mass Spectrometry
Pp. 135-147
Alfred Hagemeyer, Andreas Lesik, Guido Streukens, Anthony
F. Volpe Jr., Howard W. Turner, W. Henry Weinberg, Karin Yaccato
and Chris Brooks
[Abstract]
Optimisation Methodologies and Algorithms for Research
on Catalysis Employing High-Throughput Methods: Comparison
Using the Selox Benchmark Pp. 149-159
Sílvia Raquel Morais Pereira, Frédéric
Clerc, David Farrusseng, Jan Cornelis van der Waal and Thomas
Maschmeyer
[Abstract]
Meet the Guest Editor
Pp. 161
Abstracts
[Back to top]
Editorial
Combinatorial Heterogeneous Catalysis
These special issues (Vol. 10, No. 1 and
Vol. 10, No. 2) are devoted to progress
in the area of Combinatorial Heterogeneous Catalysis (CHC),
which can be considered to be the general application of combinatorial
and high-throughput methods and strategies in materials research.
Heterogeneous catalysis plays a vital role if our everyday
lives. All pollution-free and environmentally friendly industrial
processes in oil refineries, chemical plants, and power energy
stations need highly active and selective catalysts. Catalysts
are used in cars and trucks to remove harmful products of
incomplete oxidation of gasoline or diesel fuel. The plastics
used in everyday life are prepared by applying very specific
highly active and selective catalysts, and this list can be
continued. Better catalysts reduce productions costs, reduce
the formation of wasteful by-products, and help to decrease
atmospheric pollution. These are the main reasons that the
search for new and better catalysts is a permanent R &
D task.
In general, combinatorial approaches are intended to find
the optimum formulation in various pharmaceutical or engineering
materials including catalysts, with the shortest interval
and minimum amount of unit cost. In this case the focus is
laid on the optimum performance with decreased overall costs.
All combinatorial approaches are based on the diversity of
the system investigated. This diversity determines the parameter
space where the optimum performance may be found. In combinatorial
materials research, including CHC, the following key components
of diversity can be distinguished: (i) compositional; (ii)
process; and (iii) structural. The structural diversity is
determined by the first two components. In order to move in
a large experimental space towards the optimum performance,
the following requirements must be fulfilled: (i) high throughput
methods in synthesis, testing, and analysis; (ii) highly reliable
and reproducible analytical methods; (iii) effective optimization
and information mining tools; and (iv) appropriate data handling
and management methods.
Today, combinatorial heterogeneous catalysis is a well-acknowledged
area of catalysis sciences, although a definite part of our
scientific community still remains quite critical. Methods
of combinatorial catalysis are widely used both in applied
and academic laboratories. Symyx Technologies was the first
company devoted to the area of combinatorial heterogeneous
catalysis. Among the followers are the Dutch company Avantium
Technologies, the German group “hte GmbH”, etc.
In the last 10 years, most of the large oil and chemical companies
created their own laboratories in combinatorial catalysis.
In academia, various combinatorial heterogeneous laboratories
have emerged in various countries, such as Australia, Japan,
Korea, Singapore, Germany, the Netherlands, Belgium, France,
UK, Norway, Spain, Hungary, Canada, USA, China, India, and
Mexico. These laboratories may be considered as the pioneers
in this field. Consequently, there is considerable geographical
diversity in the location of key laboratories.
The importance of this field has been documented by various
international meetings fully or partly devoted to CHC. Most
of the international meetings in the field of heterogeneous
catalysis have an independent section devoted fully to high
throughput and combinatorial methods. In several highly ranked
meetings (Europacat, International Catalysis Congress), round
table discussions took place that were excellent forums for
listening to both the pros and the cons of CHC. It should
be mentioned that there is a special “heterogeneous
catalysis” section at the Gordon Research Conferences
devoted to the field of combinatorial materials research.
If we look back to the first publications in the area of CHS,
we see that the focus has been on the methodology and the
use of high-throughput techniques and technologies. In this
period, gas phase catalytic reactions were usually investigated.
Today, after ten years of practice in this field, the area
of activity in CHC has been expanded considerably. Combinatorial
methods are used today to develop catalysts for applications
such as (i) gas and liquid phase reaction both at atmospheric
and high pressures; (ii) electro-catalysts for fuel cell technology;
and (iii) photo-catalysts for water splitting and environmental
control. New sophisticated preparation methods, such as inkjet
printing, laser ablation, co-spattering, etc., are also being
applied. The use of micro-reactor technologies and complete
atomization and robotization is now common. In addition, ever
more attention is now being paid on optimization, information
mining, and data handling - in other words, on the development
of a complex informatic workflow.
This approach is also reflected by the content of this special
issue, where new aspects of combinatorial heterogeneous catalysis
are discussed, such as the use of methods of computational
chemistry, application of prediction and modeling tools, use
of new visualization and optimization methods, and description
of a complex new informatic platform. In addition, new preparation
and screening methods are also described and the use of high-throughput
method for “knowledge extraction” is presented
as well.
As guest editor, I have tried my best to increase the geographical
diversity of the authors. This effort is reflected by the
selection of authors representing different countries including
Australia, France, Germany, Hungary, Japan, Korea, Spain,
The Netherlands, and the United States. Altogether, 13 contributions
will be published in two parts.
I would like to thank all the authors and reviewers for their
contributions, help and cooperation. I hope that this special
issue will help the existing and newly forming groups all
around the world to strengthen the position and acceptance
of combinatorial heterogeneous catalysis. I also believe that
as more success stories are published in this field, resistance
from the academic society will diminish. In this case, we
can also hope that the results obtained using combinatorial
and high-throughput methods can be freely published in leading
catalysis journals, too. I would also suggest for all of those
who are still skeptical and are against the use of “combi”
approaches in academic research to visit as many “combi”
laboratories as possible and talk and listen to students and
young scientists working successfully in this field. When
you will look into the proud eyes of these young people, you
will get the right message portraying the future of combinatorial
heterogeneous catalysis.
József L. Margitfalvi
(Guest Editor)
Department of Organic Catalysis
Institute of Surface Chemistry and Catalysis
Chemical Research Center
Hungarian Academy of Sciences
Budapest
Hungary
E-mail: joemarg@chemres.hu
[Back to top]
Development of an Integrated Informatics Toolbox:
HT Kinetic and Virtual Screening
David Farrusseng, Frédéric Clerc, Claude
Mirodatos, Nabeel Azam, Francois Gilardoni, Joris W. Thybaut,
Periyasamy Balasubramaniam and Guy B. Marin
We discuss thoroughly aspects and issues for the development
of a bespoke, but generic, electronic infrastructure designed
to cope with the dynamic in high-throughput experimentation
and knowledge management, is applicable to large or contract
research organizations. We present the first generation of
an informatics platform developed for TOPCOMBI, a research
project funded by the European Commission for Nanotechnology
and Nanoscience. It is composed by an infrastructure and a
collection of modules dealing with laboratory analytics, robotics,
data handling and analytics, optimization, in-database processing
and visualization, which are developed collegially by the
partners of the Consortium. This best-of-breed informatics
system enables the capture and the re-usage of processes and
methodologies, i.e. process and data flows, using the workflow
paradigm. Complex workflows designed by power users can be
eventually used by either other domain experts or by novices
through a web portal. Workflows can also be run interactively
to allow visual analytics for instance, or automatically.
We present two case studies dealing with the kinetic study
of glycerol catalytic oxidation using parallel equipments,
and a novel, fully integrated QSAR applied in heterogeneous
catalysis, respectively.
[Back to top]
Combinatorial Computational Chemistry Approach for
Materials Design: Applications in deNOx Catalysis, Fischer-Tropsch
Synthesis, Lanthanoid Complex, and Lithium Ion Secondary Battery
Michihisa Koyama, Hideyuki Tsuboi, Akira Endou, Hiromitsu
Takaba, Momoji Kubo, Carlos A. Del Carpio and Akira Miyamoto
Computational chemistry can provide fundamental knowledge
regarding various aspects of materials. While its impact in
scientific research is greatly increasing, its contributions
to industrially important issues are far from satisfactory.
In order to realize industrial innovation by computational
chemistry, a new concept “combinatorial computational
chemistry” has been proposed by introducing the concept
of combinatorial chemistry to computational chemistry. This
combinatorial computational chemistry approach enables theoretical
high-throughput screening for materials design. In this manuscript,
we review the successful applications of combinatorial computational
chemistry to deNOx catalysts, Fischer-Tropsch catalysts,
lanthanoid complex catalysts, and cathodes of the lithium
ion secondary battery.
[Back to top]
High-Throughput Nanoparticle Catalysis: Partial Oxidation
of Propylene
Shici Duan, Michael Kahn and Selim Senkan
Partial oxidation of propylene was investigated at 1 atm pressure
over Rh/TiO2 catalysts as a function of reaction
temperature, metal loading and particle size using high-throughput
methods. Catalysts were prepared by ablating thin sheets of
pure rhodium metal using an excimer laser and by collecting
the nanoparticles created on the external surfaces of TiO2
pellets that were placed inside the ablation plume. Rh nanoparticles
before the experiments were characterized by transmission
electron microscopy (TEM) by collecting them on carbon film.
Catalyst evaluations were performed using a high-throughput
array channel microreactor system coupled to quadrupole mass
spectrometry (MS) and gas chromatography (GC). The reaction
conditions were 23% C3H6, 20% O2
and the balance helium in the feed, 20,000 h-1
GHSV and a temperature range of 250-325 0C. The
reaction products included primarily acetone (AT) and to a
lesser degree propionaldehyde (PaL) as the C3 products,
together with deep oxidation products COx.
[Back to top]
Assessment of Predictive Ability of Artificial Neural
Networks Using Holographic Mapping
András Tompos, Lajos Végvári, Erno
Tfirst and József L. Margitfalvi
In this study, artificial neural networks (ANNs) were used
to reveal a quantitative relationship between catalytic composition
and catalytic activity. This relationship was predefined using
a hypothetical experimental space described by a multidimensional
polynomial. The predictive ability of ANNs was investigated,
i.e. an attempt was done to evaluate how ANNs can envisage
a given hypothetical experimental space. Data sets for training,
validation and testing of ANNs were obtained from the hypothetical
experimental space using two different ways of sampling. Data
were selected, (i) by means of our optimization algorithm
called Holographic Research Strategy (HRS); and (ii) randomly.
In order to model real experimentation, data were also generated
with error. The relationship between the complexity of different
network topologies and their predictive ability was investigated.
It was shown that when data used for training have been perturbed
with a given level of noise, less complex network architectures
give acceptable accuracy. Additionally, estimated experimental
spaces were visualized in a 2D layout by means of Holographic
Mappings (HMs). Analysis of HMs revealed that ANNs trained
by data sets obtained upon an optimization procedure provides
better description of the experimental space in the vicinity
of the optimum than ANNs trained by randomly selected data
sets. This fact indicates again the importance of the optimization
in combinatorial catalyst library design.
[Back to top]
Discovery of Novel Catalytic Materials for Emissions
Control Using High Throughput Scanning Mass Spectrometry
Alfred Hagemeyer, Andreas Lesik, Guido Streukens, Anthony
F. Volpe Jr., Howard W. Turner, W. Henry Weinberg, Karin Yaccato
and Chris Brooks
High-throughput approaches were applied to the discovery of
more efficient catalysts for various applications in emissions
control. The screening approach was based on a hierarchy of
qualitative or semi-quantitative primary screens for discovery
of hits and quantitative secondary screens for confirmation
and scale-up of leads. In this work, primary screening was
carried out by fast scanning mass spectrometry (SMS) for NOx
abatement, low temperature CO oxidation, VOC removal, COx
methanation and the water gas shift (WGS) reaction.
[Back to top]
Optimisation Methodologies and Algorithms for Research
on Catalysis Employing High-Throughput Methods: Comparison
Using the Selox Benchmark
Sílvia Raquel Morais Pereira, Frédéric
Clerc, David Farrusseng, Jan Cornelis van der Waal and Thomas
Maschmeyer
The Selox is a catalytic benchmark for the selective CO oxidation
reaction in the presence of H2, in the form of
mathematical equations obtained via modelling of
experimental results. The optimisation efficiencies of several
Global Optimisation algorithms were studied using the Selox
benchmark. Genetic Algorithms, Evolutionary Strategies, Simulated
Annealing, Taboo Search and Genetic Algorithms hybridised
with Knowledge Discovery procedures were the methods compared.
A Design of Experiments search strategy was also exemplified
using this benchmark. The main differences regarding the applicability
of DoE and Global optimisation techniques are highlighted.
Evolutionary strategies, Genetic algorithms, using the sharing
procedure, and the Hybrid Genetic algorithms proved to be
the most successful in the bench-mark optimisation.
|
