3.2.3. Hydroformylation 2467 3.2.4. Dimerization 2468 3.2.5. Oxidative Cleavage and Ozonolysis 2469 3.2.6. Metathesis 2470 4. Terpenes 2472 4.1. Pinene 2472 4.1.1. Isomerization: R-Pinene 2472 4.1.2. Epoxidation of R-Pinene 2475 4.1.3. Isomerization of R-Pinene Oxide 2477 4.1.4. Hydration of R-Pinene: R-Terpineol 2478 4.1.5. Dehydroisomerization 2479 4.2. Limonene 2480 4.2.1. Isomerization 2480 4.2.2. Epoxidation: Limonene Oxide 2480 4.2.3. Isomerization of Limonene Oxide 2481 4.2.4. Dehydroisomerization of Limonene and Terpenes To Produce Cymene 2481

Chemical Routes for the Transformation of Biomass into Chemicals

The open literature concerning chemical and mechanistic aspects of the selective catalytic reduction of NO by ammonia (SCR process) on metal oxide catalysts is reviewed. Catalytic systems based on supported V2O5 (including the industrial TiO2-supported V2O5–WO3 and/or V2O5–MoO3 catalysts) and catalysts containing Fe2O3, CuO, MnOx and CrOx are considered. The results of spectroscopic studies of the adsorbed surface species, adsorption–desorption measurements, flow reactor and kinetic experiments are analyzed. The proposed reaction mechanisms are described and critically discussed. Points of convergence and of disagreement are underlined.

Chemical and mechanistic aspects of the selective catalytic reduction of NOx by ammonia over oxide catalysts: A review

https://publikationen.bibliothek.kit.edu/1000050288/18451059

Renewable Power-to-Gas: A technological and economic review

Zinc–air is a century-old battery technology but has attracted revived interest recently. With larger storage capacity at a fraction of the cost compared to lithium-ion, zinc–air batteries clearly represent one of the most viable future options to powering electric vehicles. However, some technical problems associated with them have yet to be resolved. In this review, we present the fundamentals, challenges and latest exciting advances related to zinc–air research. Detailed discussion will be organized around the individual components of the system – from zinc electrodes, electrolytes, and separators to air electrodes and oxygen electrocatalysts in sequential order for both primary and electrically/mechanically rechargeable types. The detrimental effect of CO2 on battery performance is also emphasized, and possible solutions summarized. Finally, other metal–air batteries are briefly overviewed and compared in favor of zinc–air.

/pdf/recent-advances-in-zinc-air-batteries-5fiw4wwwgg.pdf

Recent advances in zinc–air batteries

Beyond Oil and Gas: The Methanol Economy

The historical development, current status and future prospects of chlor-alkali electrolysis with oxygen depolarized cathodes (ODCs) are summarized. Over the last decades, membrane chlor-alkali technology has been optimized to such an extent that no substantial reduction of the energy demand can be expected from further process modifications. However, replacement of the hydrogen evolving cathodes in the classical membrane cells by ODCs allows for reduction of the cell voltage and correspondingly the energy consumption of up to 30%. This replacement requires the development of appropriate cathode materials and novel electrolysis cell designs. Due to their superior long-term stability, ODCs based on silver catalysts are very promising for oxygen reduction in concentrated NaOH solutions. Finite-gap falling film cells appear to be the technically most mature design among the several ODC electrolysis cells that have been investigated.

Chlor-alkali electrolysis with oxygen depolarized cathodes: history, present status and future prospects

Alkaline water electrolysis is a key technology for large-scale hydrogen production powered by renewable energy. As conventional electrolyzers are designed for operation at fixed process conditions, the implementation of fluctuating and highly intermittent renewable energy is challenging. This contribution shows the recent state of system descriptions for alkaline water electrolysis and renewable energies, such as solar and wind power. Each component of a hydrogen energy system needs to be optimized to increase the operation time and system efficiency. Only in this way can hydrogen produced by electrolysis processes be competitive with the conventional path based on fossil energy sources. Conventional alkaline water electrolyzers show a limited part-load range due to an increased gas impurity at low power availability. As explosive mixtures of hydrogen and oxygen must be prevented, a safety shutdown is performed when reaching specific gas contamination. Furthermore, the cell voltage should be optimized to maintain a high efficiency. While photovoltaic panels can be directly coupled to alkaline water electrolyzers, wind turbines require suitable converters with additional losses. By combining alkaline water electrolysis with hydrogen storage tanks and fuel cells, power grid stabilization can be performed. As a consequence, the conventional spinning reserve can be reduced, which additionally lowers the carbon dioxide emissions.

/pdf/alkaline-water-electrolysis-powered-by-renewable-energy-a-2n96wa9pp8.pdf

Alkaline Water Electrolysis Powered by Renewable Energy: A Review

Monolith reactors are being studied as a replacement for conventional multiphase reactors such as trickle-bed reactors, slurry reactors, and slurry bubble column reactors for gas–liquid–solid reactions. Reactors with monolith catalyst packing have been found to be hydrodynamically superior to existing industrial reactors. This review covers multiphase reactions carried out in monolith reactors by various researchers. It first defines the monolith reactor and looks into the geometrical aspects of monolith. The section dealing with hydrodynamics reviews pressure drop, phase holdup, flow distribution, and dispersion characteristics. This study also considers the tools used to characterize the hydrodynamic parameters and their typical values. Although the available literature is scarce, monoliths are considered to have superior mass transfer characteristics. This review lists the mass transfer correlations for each category (gas–liquid, gas–solid, liquid–solid). The last section discusses the reaction aspects of monolith reactors. The ultimate goal is to implement such reactors for multiphase reactions. This section also compares the performance of monolith reactors with conventional multiphase reactors and lists the various reactor models reported to predict the overall performance of monolith reactors. © 2004 American Institute of Chemical Engineers AIChE J, 50: 2918–2938, 2004

Monoliths as multiphase reactors: A review

The hydrogenolysis of esters to alcohols is a reaction between esters and hydrogen which selectively splits a C-0 bond adjacent to a carbonyl group (1). A well-known large-scale industrial process based on this reaction the production of fatty alcohols from natural fatty acid esters-has been operated commercially for more than 50 years. Several processes which include the hydrogenolysis of an ester have been proposed for the manufacture of basic chemicals such as methanol and ethanol. Furthermore, there has been continuous interest over the past two decades in replacing the existing, energy-intensive processes for the production of ethylene glycol and 1,4-butanedioI by more cost-effective routes involving ester hydrogenolysis. While particular aspects of the literature on hydrogenolysis of esters have been reviewed already [1–3], the objective of the present work is to give a more general summary with special emphasis on the present or possible industrial applications of ester hydrogenolysis.

The Catalytic Hydrogenolysis of Esters to Alcohols

The article contains sections titled:



1.	Introduction	
1.1.	Types of Catalysis	
1.2.	Catalysis as a Scientific Discipline	
1.3.	Industrial Importance of Catalysis	
1.4.	History of Catalysis	
2.	Theoretical Aspects	
2.1.	Principles and Concepts	
2.1.1.	Sabatier's Principle	
2.1.2.	The Principle of Active Sites	
2.1.3.	Surface Coordination Chemistry	
2.1.4.	Modifiers and Promoters	
2.1.5.	Active Phase – Support Interactions	
2.1.6.	Spillover Phenomena	
2.1.7.	Phase-Cooperation and Site-Isolation Concepts	
2.1.8.	Shape-Selectivity Concept	
2.1.9.	Principles of the Catalytic Cycle	
2.2.	Kinetics of Heterogeneous Catalytic Reactions	
2.2.1.	Concepts of Reaction Kinetics (Microkinetics)	
2.2.2.	Application of Microkinetic Analysis	
2.2.3.	Langmuir – Hinshelwood – Hougen – Watson Kinetics	
2.2.4.	Activity and Selectivity	
2.3.	Molecular Modeling in Heterogeneous Catalysis	
2.3.1.	Density Functional Theory	
2.3.2.	Kinetic Monte Carlo Simulation	
2.3.3.	Mean-Field Approximation	
2.3.4.	Development of Multistep Surface Reaction Mechanisms	
3.	Development of Solid Catalysts	
4.	Classification of Solid Catalysts	
4.1.	Unsupported (Bulk) Catalysts	
4.1.1.	Metal Oxides	
4.1.1.1.	Simple Binary Oxides	
4.1.1.2.	Complex Multicomponent Oxides	
4.1.2.	Metals and Metal Alloys	
4.1.3.	Carbides and Nitrides	
4.1.4.	Carbons	
4.1.5.	Ion-Exchange Resins and Ionomers	
4.1.6.	Molecularly Imprinted Catalysts	
4.1.7.	Metal – Organic Frameworks	
4.1.8.	Metal Salts	
4.2.	Supported Catalysts	
4.2.1.	Supports	
4.2.2.	Supported Metal Oxide Catalysts	
4.2.3.	Surface-Modified Oxides	
4.2.4.	Supported Metal Catalysts	
4.2.5.	Supported Sulfide Catalysts	
4.2.6.	Hybrid Catalysts	
4.2.7.	Ship-in-a-Bottle Catalysts	
4.2.8.	Polymerization Catalysts	
4.3.	Coated Catalysts	
5.	Production of Heterogeneous Catalysts	
5.1.	Unsupported Catalysts	
5.2.	Supported Catalysts	
5.2.1.	Supports	
5.2.2.	Preparation of Supported Catalysts	
5.3.	Unit Operations in Catalyst Production	
6.	Characterization of Solid Catalysts	
6.1.	Physical Properties	
6.1.1.	Surface Area and Porosity	
6.1.2.	Particle Size and Dispersion	
6.1.3.	Structure and Morphology	
6.1.4.	Local Environment of Elements	
6.2.	Chemical Properties	
6.2.1.	Surface Chemical Composition	
6.2.2.	Valence States and Redox Properties	
6.2.3.	Acidity and Basicity	
6.3.	Mechanical Properties	
6.4.	Characterization of Solid Catalysts under Working Conditions	
6.4.1.	Temporal Analysis of Products (TAP Reactor)	
6.4.2.	Use of Isotopes	
6.4.3.	Use of Substituents, Selective Feeding, and Poisoning	
6.4.4.	Spatially Resolved Analysis of the Fluid Phase over a Catalyst	
6.4.5.	Spectroscopic Techniques	
7.	Design and Technical Operation of Solid Catalysts	
7.1.	Design Criteria for Solid Catalysts	
7.2.	Catalytic Reactors	
7.2.1.	Classification of Reactors	
7.2.2.	Laboratory Reactors	
7.2.3.	Industrial Reactors	
7.2.4.	Special Reactor Types and Processes	
7.2.5.	Simulation of Catalytic Reactors	
7.3.	Catalyst Deactivation and Regeneration	
7.3.1.	Different Types of Deactivation	
7.3.2.	Catalyst Regeneration	
7.3.3.	Catalyst Reworking and Disposal	
8.	Industrial Application and Mechanisms of Selected Technically Relevant Reactions	
8.1.	Synthesis Gas and Hydrogen	
8.2.	Ammonia Synthesis	
8.3.	Methanol and Fischer – Tropsch Synthesis	
8.3.1.	Methanol Synthesis	
8.3.2.	Fischer – Tropsch Synthesis	
8.4.	Hydrocarbon Transformations	
8.4.1.	Selective Hydrocarbon Oxidation Reactions	
8.4.1.1.	Epoxidation of Ethylene and Propene	
8.4.1.2.	Ammoxidation of Hydrocarbons	
8.4.2.	Hydroprocessing Reactions	
8.5.	Environmental Catalysis	
8.5.1.	Catalytic Reduction of Nitrogen Oxides from Stationary Sources	
8.5.2.	Automotive Exhaust Catalysis

Thomas Turek

Papers

Chlor-alkali electrolysis with oxygen depolarized cathodes: history, present status and future prospects

Alkaline Water Electrolysis Powered by Renewable Energy: A Review

Monoliths as multiphase reactors: A review

The Catalytic Hydrogenolysis of Esters to Alcohols

Heterogeneous Catalysis and Solid Catalysts