Development Of Catalytic Processes Research Articles

ChemInform Abstract: Cyclodextrins and Their Applications in Aqueous‐Phase Metal‐Catalyzed Reactions

AbstractReview: 132 refs.

Cyclodextrins and their applications in aqueous-phase metal-catalyzed reactions

Abstract During these last years, cyclodextrins have greatly contributed to the development of catalytic processes in water. These cyclic oligosaccharides composed of 6(α), 7(β) or 8(γ) glucopyranose units improve the mass transfer in aqueous-organic two-phase systems and are useful compounds to design new catalysts. Thus, chemically modified cyclodextrins can be used to: (1) significantly increase the rate and selectivity of reactions catalyzed by water-soluble organometallic complexes; (2) design new water-soluble ligands for aqueous organometallic catalysis; (3) stabilize catalytically active noble metal nanoparticles in water; (4) facilitate reactions catalyzed by supported metals or metallic powder in water.

Chemically Modified Cyclodextrins: An Attractive Class of Supramolecular Hosts for the Development of Aqueous Biphasic Catalytic Processes

During these last years, cyclodextrins have contributed greatly to the development of catalytic processes in water. These cyclic oligosaccharides composed of 6(α), 7(β) or 8(γ) glucopyranose units improve the mass transfer in aqueous-organic two-phase systems and are useful compounds to design new catalysts. Thus, chemically modified cyclodextrins can be used to: (i) increase significantly the rate and selectivity of reactions catalyzed by water-soluble organometallic complexes, (ii) design new water-soluble ligands for aqueous organometallic catalysis, (iii) stabilize catalytically active noble metal nanoparticles in water and (iv) favour the dispersion and activation of the palladium on charcoal in water.

Study of Complex Reactions under Rapid Deactivation -- Improvements in the Reaction Equipment and in the Methodology for Kinetic Calculation

The technological development of catalytic processes under rapid deactivation requires the rigorous calculation of the deactivation kinetic equation in order to be useful in the simulation and optimization of industrial processes. Accordingly, suitable equipment for reaction and product analysis and a rigorous methodology for kinetic data analysis are required. These aspects are approached in this paper using the transformation of methanol into olefins on a SAPO-18 as the model reaction. In this reaction, deactivation is rapid and there is also an initiation period depending on process conditions. The correct use of gas chromatography allows for improving the collection of experimental data of composition with time-on-stream, given that, on the one hand, it minimizes the time required for analysis (4 min), and on the other, a better homogenization of the reaction product sample is achieved, which allows for a more accurate determination of the composition corresponding to a given time-on-stream. Furthermore, the rigorous kinetic modelling of deactivation requires a data analysis methodology that considers the past history of the catalyst and an activity to be defined based on a rigorous physical meaning. Accordingly, the concept of the integrated kinetic model has been used in this paper, whose basis is the calculation of kinetic parameters by simultaneously solving the zero time-on-stream kinetic model and the kinetic equation for deactivation.

Liquid‐Phase Catalytic Processing of Biomass‐Derived Oxygenated Hydrocarbons to Fuels and Chemicals

Biomass has the potential to serve as a sustainable source of energy and organic carbon for our industrialized society. The focus of this Review is to present an overview of chemical catalytic transformations of biomass-derived oxygenated feedstocks (primarily sugars and sugar-alcohols) in the liquid phase to value-added chemicals and fuels, with specific examples emphasizing the development of catalytic processes based on an understanding of the fundamental reaction chemistry. The key reactions involved in the processing of biomass are hydrolysis, dehydration, isomerization, aldol condensation, reforming, hydrogenation, and oxidation. Further, it is discussed how ideas based on fundamental chemical and catalytic concepts lead to strategies for the control of reaction pathways and process conditions to produce H(2)/CO(2) or H(2)/CO gas mixtures by aqueous-phase reforming, to produce furan compounds by selective dehydration of carbohydrates, and to produce liquid alkanes by the combination of aldol condensation and dehydration/hydrogenation processes.

High throughput screening of Monophos instant ligand library leads to a ton-scale asymmetric hydrogenation process

The development of catalytic processes for pharmaceuticals intermediates is often under severe time-pressure. To cope with this constraint, high throughput experimentation (HTE) methods have been implemented for catalyst finding. In this article, we present the HTE protocols put in place at DSM in the area of enantioselective hydrogenation. They mostly rely on libraries of monodentate chiral phosphoramidites ligands. We applied our instant ligand library technology to solve a real-life case, i.e. the asymmetric hydrogenation of an α-substituted cinnamic acid derivative. This has led to a multi-ton scale process.

High-Throughput Technologies to Enhance Innovation in Catalysis

High-throughput experimentation, employed in conjunction with rational experimental design, simulation and data-processing methods, is producing great improvements in the effectiveness of catalysis research and the development of catalytic processes by making it possible to survey parameter space in its entirety and improve the coordination of the various phases of a development trajectory.

Enones as Latent Enolates in Catalytic Processes: Catalytic Cycloreduction, Cycloaddition and Cycloisomerization

AbstractFor Abstract see ChemInform Abstract in Full Text.

Direct gas-phase interaction of aryldiazoacetates and dirhodium catalystsElectronic supplementary information (ESI) available: 1H NMR spectra for compounds 1 and 2. See http://www.rsc.org/suppdata/dt/b3/b309809p/

Interaction of two dirhodium catalysts [Rh2(O2CR)4] (R = CMe3 and CF3) with methyl-p-methoxyphenyldiazoacetate in the gas phase has resulted in the partial or complete loss of dinitrogen from diazo substrate and afforded two new hybrid products that are of interest for the further development of catalytic processes.

Enones as Latent Enolates in Catalytic Processes: Catalytic Cycloreduction, Cycloaddition and Cycloisomerization

The development of catalytic processes predicated on the use of enones as latent enolates circumvents the utilization of chemically labile enol derivatives while enabling regioselective enolate formation. In this account,an overview of this emerging area of catalytic synthetic methodology is presented with an emphasis on intramolecular processes.

ChemInform Abstract: New Methodologies and Reactors for Catalytic Process Development

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

On the link between intrinsic catalytic reactions kinetics and the development of catalytic processes: Catalytic dehydrogenation of ethylbenzene to styrene

A procedure linking kinetic modeling of catalytic reactions to reactor modeling for different configurations is developed and applied to the catalytic dehydrogenation of ethylbenzene to styrene. The procedure is applied to four configurations, namely fixed bed with/without hydrogen selective membranes and bubbling fluidized beds with/without selective membranes. The kinetic data for the industrial catalyst are extracted from industrial fixed bed data using a rigorous heterogeneous model. The kinetic data for the three in-house prepared catalysts are obtained from the laboratory scale experiments using pseudo-homogeneous models.

Research and development of catalytic processes for petroleum and natural gas conversions in the Dalian Institute of Chemical Physics

The Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences has a long history in the R&D of catalysts and catalytic processes for petroleum and natural gas conversions in China. In this paper, results and features of some commercialized petrochemical catalysts and processes as well as newly developed processes for natural gas conversion in the pilot-plant stage are described.

Catalytic process development: A process designer's point of view

Catalytic process development: A process designer's point of view

Enantioselective CC and CH Bond Formation Mediated or Catalyzed by Chiral ebthi Complexes of Titanium and Zirconium

AbstractThe development of catalytic processes that effect enantioselective bond formation under mild conditions is an important and challenging task in modern chemical synthesis. In this connection, chiral C2‐symmetric ansa‐metallocenes (bridged metallocenes) have found notable applications as catalysts. This article discusses the chemistry of this class of chiral metallocene complexes with regard to their utility in catalytic and enantioselective CC and CH bond formation reactions. In addition, where applicable, a brief comparison with other related catalytic enantioselective processes is offered. Many of the reactions effected with high levels of enantioselectivity by catalytic amounts of these complexes are of great significance to the preparation of new materials and in the synthesis of therapeutic agents. For example, zirconocene complexes readily catalyze the enantioselective addition of alkylmagnesium halides to alkenes, and cationic zirconocene complexes may promote the highly stereoregulated copolymerization of terminal alkenes. Furthermore, the related chiral titanocenes are involved in an impressive range of useful asymmetric catalytic reactions, including the enantioselective hydrogenation of olefins and reduction of imines or ketones. This review attempts to bring together the practical aspects of the use of [(ebthi)M] complexes of Group 4 transition metals (catalyst synthesis and resolution), outline the manner in which the C2‐symmetric chiral ligands are believed to initiate stereoselective bond formation, and highlight the aspects of this chemistry that are less well understood and require further research.

Catalysis at Ciba-Geigy

After an introduction describing the significance and a short history of catalysis at Ciba-Geigy, the present role of the Catalysis Section within the Central Research Services is outlined. Its main activities are preparative services for the synthetic chemists in the fields of hydrogenation and high-pressure reactions, the development of catalytic processes and a research program in the fields of enantioselective catalysis, the modification of heterogeneous catalytic systems, acid-base catalysis and catalytic C–C-bond forming reactions. Because catalysis is considered by Ciba-Geigy to be a key technology, the main goal of its R+D program in catalysis is to create and maintain a reliable scientific and technical foundation for the optimal application of catalytic reactions throughout the company. Some results are presented that illustrate the work described above and an outlook on the opportunities of catalytic technologies in the fine chemicals industry is given.

Catalysis in the Industrial Production of Pharmaceuticals and Fine Chemicals

The history of catalysis at Roche and its present relevance for the company is described. The main focus is on catalytic hydrogenation, which serves as an example to show the historic background of catalysis at Roche and to demonstrate the importance of a transdisciplinary approach used in industry – in particular in the Roche group – for the design and development of catalytic processes. The article concludes with the statement that catalysis will maintain or even strengthen its position in fine chemicals production.

A computer aided engineering system for development of catalytic processes

A system for process design and simulation of catalytic processes is described. It is used extensively for development and design of catalytic processes for production of gasses such as hydrogen, carbon monoxide, mixtures of hydrogen and nitrogen, and for design of processes for production of ammonia and methanol. New applications are the design processes for hydrotreating and catalytic purification of gases, and the design of fuel cell power plants. The processes are characterized by a high degree of integration between the different sections of a plant, and a method for managing the data flow is, therefore, necessary for efficient evaluation and analysis. This is accomplished by the so-called CAE-system, which includes a data base system with stored stream and equipment properties. The system can automatically transfer the data from one program to the other, so they can be used for equipment design. The data can also be transferred automatically to a flowsheet enabling the user to produce a drawing and all the required data with an easy interpretation of the process calculation. The process calculation itself is carried out by using a general heat and material balance program, GHEMB, which in addition to the common unit operations also contains simplified reactor modules. Rigorous modules can be used for a detailed design of catalytic reactors by execution of specific programs. These specific programs can be called from — and thus integrated into — a GHEMB calculation. In the paper, the GHEMB program and the CAE system are described, the use of different reactor type models is discussed and an example of design of fuel cell power plants is shown.

METHANE CONVERSION TECHNOLOGY AND ECONOMICS

Abstract The direct conversion of methane to petrochemical feedstocks and to transportation fuels, by-passing the synthesis gas step, is a continuing challenge in catalytic process development. There are high economic incentives to commercialize direct methane conversion to formaldehyde and methanol, and even higher economic incentives for conversion to ethylene and aromatic hydrocarbons. Current process developments in the direct conversion of methane to methanol, formaldehyde, ethylene and aromatics are reviewed. The processes are discussed in terms of process conditions, catalysts used, methane conversion, and product selectivities. The economics of direct methane conversion are discussed. An economic evaluation of ethylene production by the oxidative coupling of methane has been carried out. Results show that laboratory methane conversions and product selectivities are now sufficiently high to make this process economically attractive compared with conventional ethylene production.

Entwicklungstendenzen in der Technik katalytischer Fluid‐Reaktionen

AbstractDevelopment trends in catalytic fluid reactions. Problems associated with raw materials, energy, and the environment have had many repercussions on the industrial development of catalytic processes. Apart from efforts to increase the use of coal‐based feedstock such as synthesis gas and methanol, particular attention is focussed upon improvements in the selectivity of industrial reactions. There appears to be a reversal of direction in the choice of phase: proven homogeneous catalysts are being heterogenized, and heterogeneous catalysts are being employed in homogeneous or liquid form. Other typical features are increased efforts to replace conventional multistep syntheses by direct syntheses, and high pressure syntheses by medium or low pressure syntheses. Finally, measures designed to regenerate or conserve catalytic activity and selectivity are becoming more and more important.