Chair for Technical ChemistryProf. Dr. K. Stöwe, Prof. Dr. W. F. Maier

Address: Universität des Saarlandes, Technische Chemie, Campus C4 2, D-66123 Saarbrücken

Combinatorial and High-Throughput Development and Optimization of Heterogeneous Catalysts and Materials

References:

[1] W. F. Maier, K. Stöwe und S. Sieg, Ang. Chem. Int. Ed. 46 (2007) 6016-6067. Combinatorial and High-Throughput Materials Science.

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"The present approach to the search for new materials suffers from a chronic ailment, that of handling one sample at a time in theprocess of synthesis, chemical analysis and testing of properties. It is an expensive and timeconsuming approach, which preventshighly trained personnel from taking full advantage of its talents and keeps the tempo of discovery at a low level."

J.J. Hanak, Journal of Materials Science (1970) 964-971

There is increasing acceptance of High-Throughput Technologies (HTT) for discovery, development and optimisation of materials and catalysts in the producing industries. Through the years a relative synchronous development of technologies for parallelized syn-thesis and characterization was accompanied by developments of associated software and information technologies. In our group all steps of the iterative high-throughput development and opti-mization cycle (see left side) are realised, well-kept and taught to students. This poster attempts to provide a comprehensive overview through selected examples from actual research topics. In general technologies developed to research catalysts and complex materials are covered as well as databases, design of experiment, data-mining technologies, modelling approaches and evolutionary strategies for development. Group Prof. Maier/Prof. Stöwe

Heike Hölzen

Responsible technician for Chemspeed Accelerator SLT 106 (SDU, LDU, 3 pressure blocks, glas reactors, glove box for inert atmosphere)outstanding problems:� crosstalk of the glas vials within the pressure block due to insufficient possibility of smooth pressure release � bubbling up of solvent on

pressure release, solvent in waste line � temporarily manual micro metering valve in exhaust line of each pressure block� insufficient accuracy of liquid dosing of surfactants like NP5 or NP10 due to high viscosity; insufficient accuracy for doping solutions� impossibility of solid dosing of several powders like e.g. soot or TMTMS (tetramethylthiuram monosulfide)� limited temperature range of 200°C maximum for reactions � separation of SLT reactor area into low (Huber Unistat 390W, HT190) and high

temperature part (Huber Unistat Tango, HT250)

Stefan Sticher Lars Hensgen

Selvakumar Jayavel Alexander Kolb

Search for selective and noble metal free liquid phase hydrogenation catalystsThe vast majority of hydrogenation catalysts consists of noble metal containing materials. These materials are not only expensive but also rare. Therefore it is desirable to find new noble metal free catalysts. With the Chemspeed Accelerator SLT 106 it is possible to screen potential liquid phase catalysts fast in a parallel mode.

For the selective hydrogenation of citral to citronellol the medium pressure blocks can be used. Figure 1 shows the reaction scheme and figure 2 the picture of one pressure block with 16 reactors. The reaction is performed at a temperature of 90 °C and a H2-pressure of 80 bars. The Chemspeed robot performs not only the reaction but also takes samples for analyses by GC.

90 °C, 80 bar

Catalyst, H2O OH

E/Z-Citral Geraniol, Nerol

Figure 1: selective hydrogenation of citral Figure 2: medium pressure reactor block(1): pressure indication, (2): connection to the burst plate,(3): control cable, (4): gas inlet and gas outlet tubes, (5): opening, (6): pressure reactors, (7): heating oil supply.

Screening of different potential catalysts for the Heck-coupling

Cross couplings are an important tool to synthesize new C-C bonds, because they tolerate a wide range of functional groups. In the range of this cross-couplings the Heck-coupling is one of the most important reactions for industrial application.

The problem of this coupling is the application of Pd catalysts, so it is interesting to find new catalysts, which have a lower or no Pd content. The combinatorial chemistry shows to be an efficient way to find new catalysts.

+I

1.2 mol% Kat, 1.2 Äq Et3N

Dekan, 110°C

Figure 1: Heck-coupling of iodobenzol and styrene to stilbeneFigure 2: 16-fold standard single jacket reactorblock (13 ml) including array of reflux condensers

wWith a suitable testing system and the ChemspeedAccelerator SLT 106 several catalysts can be tested parallel in the liquid phase under the same conditions. By this way the large number of different materials which is produced by the combinatorial process can be analyzed faster and with better reproducibility than in the conventional way.

1.2 mol% cat., 1.2 equiv. Et3N

decane, 110°C

Development of new nano-scaled mixed metal sulfide catalysts with the help of combinatorial and high-throughput methods

The development of a high-throughput synthesis method is a key step in the research for new heterogeneous catalysts based on nano-sized mixed metal sulfides when applying combinatorial methods. The use of the Chemspeed synthesis robot provides a potential high-throughput approach for the preparation of these mixed metal sulfides. The synthesis of the nanoparticles is conducted in a microemulsion (ME). The four needle head unit is used for a standardised preparation of the ME in the reaction vessel (16fold medium pressure block with glass inlets). The addition of the sulfide source to the ME is carried out by the solid dosing unit (SDU) with customised extruders. The metal precursor is added prior to the ME. This experimental procedure allows the parallel synthesis of 48 metal sulfides (use of three medium pressure blocks) under various reaction conditions.

x Mn+ + y H2S(aq) MxSy + 2y H+Oil

H2O

Surfactant

Figure 1: Inverse microemulsion; micelles as particle size confining nano-reactors

Different sulfide precursors like TMTMS release sulfide anions under varying conditions as e.g. elevated pressures; sulfideanions are hydrolysed upon diffusion into the water core where the metal precursors are dissolved and react with the sulfideanions forming mixed metal sulfides of various compositions.

[1]

Figure 1: automated dosing of 50mg solid supports by ChemspeedAccelerator SLT106

Figure 2: ecIRT image of catalystlibrary based on impregnated CeO2supports in 4000ppm C3H8, 2000 ppmNO and 5% O2 in N2 at 300°C; Thermosensorik IR camera with 256 x 256 PtSi FPA detector .

Supports supplied by Evonik:- VP Nanoceria 50- VP ZrO2 PH- VP ZrO2 3YSZ- TiO2 P25- Al2O3 C- SiO2 Aerosil 200

Combinatorial discovery of catalysts for the reduction of diesel en-gine exhaust emissionsOur developments of new catalysts are based on a high-throughput workflow for NOx and HC reduction from automobile exhausts to meet future emission standards. Catalyst syntheses were carried out by impregnation of solid supports. Solid dosing was done efficiently using a Chemspeed Accelerator SLT106, dosing of different dopant solutions to the solid supports was done by a Packard robot. After drying the catalysts were calcined, grinded and filled manually into a slate library plate with 206 holes. Primary screening of library is performed using emission-corrected IR-thermography (ecIRT) in different gas atmospheres (C3H8,O2,NO,N2). Conventional measurements (secondary screening) were done based on potential hits of primary screening measurements.

4NO + C3H8 + 3O2 2N2 + 3CO2 + 4H2O