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The transformation of low cost sugar feedstocks into market chemicals and monomers for existing or novel high performance polymers by chemical catalysis is reviewed. Emphasis is given to industrially relevant, continuous flow, trickle bed processes. Since long-term catalyst stability under hydrothermal conditions is an important issue to be addressed in liquid phase catalysis using carbohydrate feedstocks, we will primarily discuss the results of catalytic performance for prolonged times on stream. In particular, the selective aerobic oxidation of glucose to glucaric acid and the subsequent selective hydrogenation to adipic acid is reviewed. Hydroxymethylfurfural (HMF), which is readily available from fructose, can be upgraded by oxidation to furan dicarboxylic acid (FDCA) or by consecutive reduction and hydrogenolysis to hexanetriol (HTO) followed by hydrogenolysis to biobased hexanediol (HDO). Direct amination of HDO yields biobased hexamethylene diamine (HMDA). Aerobic oxidation of HDO represents an alternative route to biobased adipic acid. HMDA and adipic acid are the monomers required for the production of nylon- 6,6, a major polymer for engineering and fibre applications.

This paper reports the combination of Holographic Mapping (HM) and Artificial Neural Networks (ANNs) in order to provide a benchmark visualization of a multi-dimensional space in two-dimensional forms. In this approach each matrix point in HM represents virtual catalytic data generated by means of ANNs in order to visualize the given multi-dimensional experimental space. A 12-dimensional experimental space related to the composition of catalysts designed for the water gas shift reaction (WGSR) from 12 possible components supported on ZrO2 is visualized. Catalytic data obtained in an earlier combinatorial screening process at 300 °C were used for training of the ANNs. The results show that the visualization of large experimental spaces having more than half a million virtual experimental points can be accomplished. The analysis of synergistic effects between different components revealed that the key components of water gas shift catalysts at 300 °C were Pt, Fe, Eu and V, while Co, Ru, Sb, Ge and Mo had a pronounced negative effect on the activity.

By applying high throughput synthesis and characterization technologies, we have been optimizing common dry or aqueous synthetic routes for the preparation of high surface area metals and oxides, such as precipitation and modified Pechini methods. For wet combustion synthesis, we have been screening a variety of organic acids as dispersants and developed proprietary recipes for individual metals. By resorting to easily decomposable organic acids (as opposed to citric acid in the original Pechini combustion method), such as glyoxylic acid, oxalacetic acid and ketoglutaric acid, it is possible to obtain high surface area materials for many metals after careful optimization of acid/metal ratio and calcination conditions. Examples are Sn, In, Co, Ru, Ni, Fe, Mn, Y, Ce and Rare Earth oxides and their mixtures. After calcination in the temperature range of about 300–400 °C, surface areas >150 m2/g could be obtained for Er, Tm, Co, Ru, and Nb; >200 m2/g for Sn, Fe, Mn, and Y; >300 m2/g for Ce; and >400 m2/g for Ni oxide. Noteworthy are also >140 m2/g for La2O3, >80 m2/g for CuO, and 75 m2/g for ZnO. For V, around 40 m2/g was possible for the nearly carbon-free V2O5, whereas up to 90 m2/g was obtained for a 90% V–10% carbon composite (by incomplete combustion of the organic acid). Residual carbon helps in stabilizing the porous oxide against sintering. Thus, conventional aqueous routes (precipitation, Pechini) can be competitive to more elaborate and costly methods such as those using organic solvents, sol–gel, supercritical drying or template/hydrothermal synthesis. Combustion synthesis is well suited for the preparation of mixed oxides from mixed metal solutions in aqueous organic acids. Bulk porous Co and CoRu mixed oxides have been screened for liquid phase alcohol oxidations and CoRuCe oxides for CO oxidation and VOC destruction, and doped NiO has been reduced to the metal and tested for various hydrogenations.

High surface area tin oxides are desirable catalyst carriers for emissions control including CO oxidation, VOC removal/methane combustion and NOx abatement. We have optimized literature procedures as well as developed proprietary recipes for the synthesis of porous SnO2 carriers. Precipitation of SnCl4 from homogeneous solution by urea and by hydrazine, the dissolution of Sn metal powder in HNO3, sol–gel routes from Sn alkoxides and inorganic Sn precursors, acid-induced gelation of K2SnO3, the Pechini method ex Sn(OAc)4 using various organic acids as dispersants and dry and wet thermal decomposition of Sn carboxylates have been investigated and compared. BET surface areas >100 m2/g have been achieved by a variety of methods after calcination in the temperature range 300–500 °C. High surface area tin oxides with excellent sintering resistance (250, 228, 190 and 175 m2/g after calcination at 300, 400, 500 and 600 °C, respectively) have been synthesized by the hydrazine method. Pt/SnO2 catalysts have been prepared by impregnation with Pt tetraamine hydroxide solution, and screened for propylene combustion and CO oxidation activity in a parallel 8 × 1 process optimization reactor. Light-off takes place at higher temperatures for CO oxidation than for propylene combustion due to Pt poisoning by CO at lower temperatures. High surface areas >200 m2/g could also be achieved by a modified Pechini method using aqueous glyoxylic acid as dispersant for Sn(IV) acetate. Ce–Sn–Co mixed oxides have been synthesized by the glyoxylic acid method, impregnated with Pt–Ru and found to be more active than Pt/Al2O3 for CO oxidation when using CO-only feed, but inferior to the Pt standard when feeding a CO–propylene mixture.

The catalytic oxidation of carbon monoxide to carbon dioxide is an important process used in several areas such as respiratory protection, industrial air purification, automotive emissions control, CO clean-up of flue gases and fuel cells. Research in this area has mainly focused on the improvement of catalytic activity at low temperatures. Numerous catalyst systems have been proposed, including those based on Pt, Pd, Rh, Ru, Au, Ag, and Cu, supported on refractory or reducible carriers or dispersed in perovskites. Well known commercial catalyst formulations for room temperature CO oxidation are based on CuMn2O4 (hopcalite) and CuCoAgMnOx mixed oxides. We have applied high-throughput and combinatorial methodologies to the discovery of more efficient catalysts for low temperature CO oxidation. The screening approach was based on a hierarchy of qualitative and semi-quantitative primary screens for the discovery of hits, and quantitative secondary screens for hit confirmation, lead optimization and scale-up. Parallel IR thermography was the primary screen, allowing one wafer-formatted library of 256 catalysts to be screened in approximately 1 hour. Multi-channel fixed bed reactors equipped with imaging reflection FTIR spectroscopy or GC were used for secondary screening. Novel RuCoCe compositions were discovered and optimized for CO oxidation and the effect of doping was investigated for supported and bulk mixed oxide catalysts. Another family of active hits that compare favorably with the Pt/Al2O3 benchmark is based on RuSn, where Sn can be used as a dopant (e.g. RuSn/SiO2) and/or as a high surface area carrier (e.g., SnO2 or Sn containing mixed metal oxides). Also, RuCu binary compositions were found to be active after a reduction pretreatment with hydrogen.

High-throughput and combinatorial approaches have been applied to the discovery of catalysts for selective low temperature CO oxidation/VOC removal using mixed CO/propylene feeds, and for the water–gas shift (WGS) reaction using real post-reformer feeds containing CO, CO2, H2O and H2. The screening approach was based on a hierarchy of qualitative and semi-quantitative primary screens for the discovery of hits, and quantitative secondary screens for hit confirmation, lead optimization and scale-up. For WGS, primary screening was carried out using scanning mass spectrometry. For CO oxidation and VOC removal, parallel IR thermography was the primary screen. Multi-channel fixed bed reactors equipped with imaging reflection FTIR spectroscopy or GC were used for secondary screening. Novel RuCoCe compositions were discovered and optimized for CO oxidation/VOC removal and the effect of doping was investigated for supported and bulk mixed oxide catalysts. For WGS, noble metal-free and Pt-doped CoFeRu mixed oxides as well as Pt on CeO2 and Pt on CeO2/ZrO2 were investigated and a new synergistic PtFeCe ternary composition was discovered. In these cases oxygen vacancies in the ceria lattice are believed to play a key role in the strong and synergistic Pt–Ce interaction. Alkaline metal doping was found to enhance the selectivity towards WGS by suppressing the unselective methanation side reaction and to increase the low temperature catalytic activity.

High-throughput synthesis and screening of libraries consisting of redox zeolites and molecular sieves have been developed for the selective oxidation of 2-butyl-5-hydroxymethyl-imidazole to the corresponding aldehyde in the liquid phase. Libraries consisting of 96 catalysts were prepared and screened for catalytic activity using high-throughput software, robotics, reactor, and screening technologies. The integrated synthesis and screening workflow allowed ∼5000 samples to be screened in less than one month. Promising hits identified in the high-throughput primary screens were successfully scaled up and optimized in conventional laboratory test units. Best results have been obtained with doubly or triply doped mesoporous sieves containing both an impregnated and framework-substituted metal. PtBi-doped framework-substituted V-MCM-41 redox mesoporous sieves were found to be efficient catalysts for aerobic oxidation under relatively mild reaction conditions (100–150°C, 15–400 psi air, 4–10 h reactio...

High-throughput synthesis and screening methods have been developed for the heterogeneously catalyzed gas phase hydrogenation of CO and CO 2 (‘methanation’) over zirconia and ceria supported noble and base metal catalysts at 300–400 °C and ambient pressure. The discovery libraries, for primary screening, consisted of 11 × 11 arrays of 111 catalysts on 3 in. quartz wafers, and 16 × 16 arrays of 256 catalysts on 4 in. quartz wafers. Catalysts were prepared by liquid dispensing techniques and screened for catalytic activity in scanning mass spectrometers (SMS). This primary screening tool uses quadrupole mass spectrometry for rapid serial detection. More than 500 potential catalysts could be screened in a single day. A kinetic model based on fast equilibration by the reverse water–gas-shift reaction in parallel with about an order of magnitude slower CO hydrogenation is in good agreement with CO x conversion data. CO 2 is mainly reverse shifted to CO. Ru, Rh, and Ni were found to promote methanation whereas Pt tends to catalyze the reverse WGS reaction. Methanation activity can be enhanced by some acidic and redox dopants or suppressed by basic dopants. High conversions were achieved in SMS demonstrating the minimal scalability risk for short contact time reactions.

The palladium/phosphine-catalyzed productive chloroarene C-Cl bond activation provides general, efficient, and functional group friendly methods for the selective oxidation of alcohols and the hydrodechlorination of chloroarenes.

High-throughput synthesis and screening methods have been developed for the discovery of highly active lead compounds for the selective catalytic reduction as well as direct decomposition of NO in the temperature range 200–300 °C. The discovery libraries for primary screening consisted of 16 × 16 catalyst arrays on 4 in. square quartz wafers. Catalysts were prepared by robotic liquid dispensing techniques and screened for catalytic activity in Symyx’ scanning mass spectrometer. The scanning mass spectrometer is a fast serial screening tool that uses flat wafer catalyst surfaces, local laser heating, a scanning/sniffing nozzle and a quadrupolar mass spectrometer to compare relative catalytic activities. The feed consisted of NO/NH3 mixtures with optional O2 cofeed and Kr as the internal standard in Ar carrier gas. QMS detection allowed for tracking of H2O, N2, NO, O2, N2O and Kr. Screening protocols for catalytic materials encompassed metal precursors and carriers for supported vanadia systems, extensive doping of V2O5/TiO2, and broad screening of mixed redox metal oxides and supported base and noble metal systems. More than 500 samples could be screened in a single day. Active hits (high NO consumption accompanied by corresponding N2 production) identified in discovery libraries were re-synthesized as focus libraries for lead confirmation and further optimization. These libraries used shallower compositional gradients, for example 56 points (compositions) per ternary, with four 56-point ternaries per 4 in. wafer. Broad screening ternaries were generally 8 or 15 points. The focus libraries more clearly reveal the trends and provide guidelines for secondary screening and scale-up. High conversions were achieved in scanning mass spectrometer so the scalability risk is small for the short contact time reactions.

High-throughput primary synthesis and screening methods have been applied to the heterogeneously-catalyzed gas phase oxidation of ethane to acetic acid using mixed metal oxide catalysts. The discovery libraries consisted of 16×16 arrays of 256 catalysts on 3″×3″ quartz wafers. Catalysts were prepared using automated liquid-dispensing techniques and screened in parallel for catalytic activity in a Symyx Technologies 256-channel microfluidic reactor. Product detection was performed using parallel colorimetric techniques on products adsorbed on silica-coated glass TLC plates. This workflow allows the screening of more than 3000 samples per day. Promising leads were confirmed in focus libraries and are being optimized in secondary screening. MoV was identified as the most active binary of redox metals and was subsequently doped with main group, rare earth, and transition metals to form ternaries. Prior art MoVX (X=Nb, Ni, Sb) catalysts were successfully reproduced and it was shown that Pd doping significantly increases the catalytic activity of these systems. Three novel MoVY ternary systems were discovered.

The application of combinatorial methods to three reactions catalyzed by multimetal oxides is described. Catalysts for the oxidative dehydrogenation of ethane to ethylene were tested using a 121- or 144-channel scanning mass spectrometer primary screening reactor and a 48-channel fixed bed secondary screening reactor; catalysts for the selective oxidation of ethane to acetic acid were tested using a 256-channel massively parallel microfluidic reactor primary screen alone, and catalysts for the selective ammoxidation of propane to acrylonitrile were tested using the massively parallel microfluidic reactor and an eight-channel fixed bed secondary/tertiary screening reactor. The details regarding catalyst design, synthesis, and screening are presented. This work has resulted in both the confirmation of published results and the generation of new lead materials for all three chemistries.

High-throughput synthesis and screening methods have been developed for the direct amination of benzene to aniline using solid cataloreactants as oxidants. The discovery libraries consisted of hundreds of samples in the primary screen, and arrays of 24 catalysts in the secondary screen. Catalysts were prepared in multi-well batch reactors and screened in parallel for catalytic activity using modified TLC detection as a primary screen and fast serial GC detection as a secondary screen. Around 25,000 samples were screened in about a year. Promising hits identified in the high-throughput screens were successfully scaled up and optimized in conventional autoclaves. Novel cataloreactant systems consisting primarily of a noble metal and a reducible metal oxide have been discovered. Rh, Ir, Pd, and Ru were found to be suitable noble metal dopants. Ni and Co oxides were the only active and selective oxidants identified. Ni is the most active oxidant but requires a Mn dopant as a stabilizer to improve the regenerability, whereas Co is stable even at high regeneration temperatures. The best performing cataloreactants contain Rh or Ir as noble metals, NiO as an oxidant, and ZrO 2 or K–TiO 2 as carrier. An optimized cataloreactant, Rh/Ni–Mn/K–TiO 2 achieved stable 10% benzene conversion and >95% selectivity to aniline at 300 °C and 300 bar. Significantly, the cataloxidant can be regenerated repeatedly without a substantial loss of performance by reoxidation in air. Any noble metal oxides formed during regeneration are effectively reduced in situ during the next amination reaction.

With rising economic demands for higher efficiency and productivity in research and development, combinatorial catalysis is increasingly being implemented to bring more catalysts per unit time to the marketplace. High-throughput automated synthesis and advanced screening technologies are now being applied to the discovery of more efficient homogeneous as well as heterogeneous catalysts and materials. The combinatorial process allows the exploration of large and diverse compositional and parameter spaces by establishing an integrated workflow of rapid parallel or combinatorial synthesis of large numbers of catalytic materials, subsequent high-throughput assaying of these compounds and large-scale data analysis. The number of experiments that can be screened has risen by orders of magnitude resulting in a much higher probability of discovering new catalysts or materials. The goal of this review is to provide an overview of selected advances that have been made in this rapidly growing field in both academia and industry over the past several years.

High-throughput synthesis and screening of polyoxometalate (POM) and supported-metal libraries have been developed for the selective aerobic oxidation of alcohols to the corresponding aldehydes/ketones in the liquid phase. Libraries consisting of 96 catalysts were prepared in multi-well reactors and screened for catalytic activity using TLC, GC and NMR detection methods. Promising hits identified in the high-throughput primary screens were successfully scaled up and optimized in conventional laboratory test units. Isolated yields confirm high selectivities of more than 90% with quantitative conversions. Substrates tested include primary and secondary alcohols. Specific results will be presented for hydroxymethyl-substituted heterocycles and bicyclo-octanols.

Catalysis plays a very important role in sustainable and green chemistry applications such as renewable resources for energy and fuels, waste recovery and recycling and low- or even zero-emissions power plants, chemical production sites and vehicles. Emissions control and environmental protection are new challenges that call for novel and far more efficient catalysts to be developed in short time periods. In this chapter, examples of the application of high-throughput methods to heterogeneously catalyzed green chemistries are discussed. High-throughput and combinatorial catalysis is ideally suited for the discovery of novel noble metal and mixed metal oxide catalyst formulations for total combustion/volatile organic compound (VOC) removal, emissions control from stationary and mobile sources (NOx abatement, CO oxidation, automotive three-way catalysis) because simple gas-phase feeds and product mixes allows for truly parallel detection and very high sample throughputs. Furthermore, these methods are advantageously applicable to multicomponent catalysts (e.g. mixed metal oxides, alloys) for selective oxidation, hydrogenation, dehydrogenation and refining, including desulfurization and denitrification. Additionally, improved fast analytical techniques are making it increasingly possible to perform high-throughput experimentation on complex real plant or vehicle feeds. This chapter focuses on the primary screening of metal oxides for low-temperature CO oxidation and VOC combustion using infrared thermography reactors and SCR DeNOx of wafer-formatted catalyst libraries using scanning mass spectrometry. Keywords: high-throughput screening; heterogeneous catalysis; catalyst libraries; emissions control

With rising economic demands for higher efficiency and productivity in research and development, combinatorial catalysis is increasingly being implemented to bring more catalysts per unit time to the marketplace. High-throughput automated synthesis and advanced screening technologies are now being applied to the discovery of more efficient homogeneous as well as heterogeneous catalysts and materials. The combinatorial process allows the exploration of large and diverse compositional and parameter spaces by establishing an integrated workflow of rapid parallel or combinatorial synthesis of large numbers of catalytic materials, subsequent high-throughput assaying of these compounds and large-scale data analysis. The number of experiments that can be screened has risen by orders of magnitude resulting in a much higher probability of discovering new catalysts or materials. The goal of this review is to provide an overview of selected advances that have been made in this rapidly growing field in both academia and industry over the past several years.

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 NO(x) abatement, low temperature CO oxidation, VOC removal, CO(x) methanation and the water gas shift (WGS) reaction.

We have shown that natural abundance 13C NMR of solutes in liquid crystals may be used to obtain order parameters from a series of temperature-dependent measurements even with limited information on the carbon shift tensors. A procedure for simultaneously analysing data at the various temperatures is proposed. We have obtained the ordering matrix as a function of temperature for various biaxial (D2h) solutes: pyrene, perylene, naphthalene, anthracene and for one effectively uniaxial probe (triphenylene), in the nematic mixture ZLI–1167. We compare these results with deuterium data where possible and we also provide estimates of the chemical shift tensors for perylene and anthracene, where solid-state data are, as yet, unavailable.