Applied Catalysis A, General (v.221, #1-2)

Catalysis as a foundational pillar of green chemistry by Paul T. Anastas; Mary M. Kirchhoff; Tracy C. Williamson (3-13).
Catalysis is one of the fundamental pillars of green chemistry, the design of chemical products and processes that reduce or eliminate the use and generation of hazardous substances. The design and application of new catalysts and catalytic systems are simultaneously achieving the dual goals of environmental protection and economic benefit. No subject so pervades modern chemistry as that of catalysis. (Ron Breslow, Chemistry Today and Tomorrow: The Central, Useful, and Creative Science) No subject so pervades modern chemistry as that of catalysis. (Ron Breslow, Chemistry Today and Tomorrow: The Central, Useful, and Creative Science)Green chemistry, the design of chemical products and processes that reduce or eliminate the use and generation of hazardous substances, is an overarching approach that is applicable to all aspects of chemistry. From feedstocks to solvents, to synthesis and processing, green chemistry actively seeks ways to produce materials in a way that is more benign to human health and the environment. The current emphasis on green chemistry reflects a shift away from the historic “command-and-control” approach to environmental problems that mandated waste treatment and control and clean up through regulation, and toward preventing pollution at its source. Rather than accepting waste generation and disposal as unavoidable, green chemistry seeks new technologies that are cleaner and economically competitive. Utilizing green chemistry for pollution prevention demonstrates the power and beauty of chemistry: through careful design, society can enjoy the products on which we depend while benefiting the environment.The economic benefits of green chemistry are central drivers in its advancement. Industry is adopting green chemistry methodologies because they improve the corporate bottom line. A wide array of operating costs are decreased through the use of green chemistry. When less waste is generated, environmental compliance costs go down. Treatment and disposal become unnecessary when waste is eliminated. Decreased solvent usage and fewer processing steps lessen the material and energy costs of manufacturing and increase material efficiency. The environmental, human health, and the economic advantages realized through green chemistry are serving as a strong incentive to industry to adopt greener technologies.Developing green chemistry methodologies is a challenge that may be viewed through the framework of the “Twelve Principles of Green Chemistry” . These principles identify catalysis as one of the most important tools for implementing green chemistry. Catalysis offers numerous green chemistry benefits including lower energy requirements, catalytic versus stoichiometric amounts of materials, increased selectivity, and decreased use of processing and separation agents, and allows for the use of less toxic materials. Heterogeneous catalysis, in particular, addresses the goals of green chemistry by providing the ease of separation of product and catalyst, thereby eliminating the need for separation through distillation or extraction. In addition, environmentally benign catalysts such as clays and zeolites, may replace more hazardous catalysts currently in use. This paper highlights a variety of ways in which catalysis may be used as a pollution prevention tool in green chemistry reactions. The benefits to human health, environment, and the economic goals realized through the use of catalysis in manufacturing and processing are illustrated by focusing on the catalyst design and catalyst applications.
Keywords: Catalysis; Green chemistry; Environmental protection;

Catalyst industry used to be primarily technology driven. Surprisingly, although many new catalyst preparation procedures and technologies have been developed and published during the past decade, only very few methods have found application in commercial catalyst production as yet. Temporarily, cost reduction has become the major driving force. But also in future, all new ideas have to compete cost-wise with state of the art technology.The alkoxy route to prepare alumina has been modified to produce silica–alumina or hydrotalcites. In the area of micro-porous catalysts, new production methods were necessary for the zeolite bound zeolites that have been introduced to the refinery industry, recently. Conventional paraffin isomerization catalysts, based on chlorinated alumina or mordenite zeolites, for the first time were confronted with commercial competition from the newly introduced sulfated zirconia catalyst system, that required a new production technology.
Keywords: Heterogeneous catalysts; Dry synthesis; Zeolite bound zeolites;

Applications of combinatorial methods in catalysis by Alfred Hagemeyer; Bernd Jandeleit; Yumin Liu; Damodara M. Poojary; Howard W. Turner; Anthony F. Volpe; W. Henry Weinberg (23-43).
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.
Keywords: Combinatorial chemistry; Homogeneous catalysis; Heterogeneous catalysis; Olefin polymerization; Combinatorial materials science; High-throughput screening; High-throughput synthesis;

Solid acid catalysis using ion-exchange resins by Mark A Harmer; Qun Sun (45-62).
In this review article, we describe the use of commercially available polymeric ion-exchange resins for a range of industrially important transformations. Recent developments both on the materials design and applications will be described. Examples of high catalytic activity will be described in areas ranging from alkylation, transalkylation, isomerization, oligomerization, acylation, esterification and nitration. The two main classes of ion-exchange resins are based upon styrene-based sulfonic acids (Amberlyst® and Dow type resins), which show very high activity in the areas of esterification and etherification, to the perfluorosulfonic acid-based catalysts including the recently developed Nafion® resin/silica nanocomposites. These show very high activity in the area of linear alkyl benzene formation, isomerization, and some select acylation type chemistries. These new types of catalysts (which have been used commercially) are adding to the ever-growing portfolio of highly active solid acid catalysts, which couple both economic and environmental drivers to improve organic transformations within the chemical industry.
Keywords: Solid acid catalysis; Ion-exchange resins; Resin/silica nanocomposites;

Production of titanium containing molecular sieves and their application in catalysis by Carlo Perego; Angela Carati; Patrizia Ingallina; Maria Angela Mantegazza; Giuseppe Bellussi (63-72).
This paper reviews several important issues related with industrial application of catalysts based on titanium silicalite-1 (TS-1). The catalyst preparation has been discussed, especially considering the most critical parameters for industrial application. Two processes already demonstrated on industrial scale (phenol hydroxylation and cyclohexanone ammoximation), and a process, under development by several industrial groups (propylene epoxidation), have been reported and discussed.The possibility to insert titanium in large pore zeolites, in order to widen the application field of this kind of materials, has been considered and the behaviour of several new materials has been reported and compared with the catalytic properties of TS-1.
Keywords: Zeolite; Titanium silicalite; Large pore titanium molecular sieves; Phenol hydroxylation; Ketones ammoximation; Alkenes epoxidation;

Recent developments in olefin epoxidation have shown promising results indicating that higher olefins can be directly epoxidized using molecular oxygen, or indirectly, by using molecular oxygen to generate an active and selective oxidant in situ during reaction. Indirect approaches have utilized bifunctional catalysts that combine new catalyst components that generate such oxidants as H2O2 in situ with the functional component that activates H2O2 for olefin epoxidation. This approach is currently limited by the low rates of in situ generation of H2O2 and subsequent low rates of olefin epoxide formation. Heavily-modified, silver catalysts have also shown promise as catalysts for propylene epoxidation. These catalysts contain much higher silver and alkali and alkaline earth metal loadings than their analogs used for ethylene epoxidation and are quite different in terms of their chemical and physical properties. Currently, these compositions exhibit activities and selectivities to propylene oxide that are too low for commercial application, although further research and development may further improve catalyst performance.Silver-based catalysts have also been used to epoxidize a wide variety of higher olefins, such as 1,3-butadiene, that do not contain allylic hydrogen atoms, or higher olefins that contain non-reactive allylic hydrogen atoms, such as norbornene. Silver-based catalysts used for selective epoxidation of non-allylic, or kinetically-hindered, olefins require promoters, typically cesium, rubidium, or thallium salts, to assist in the desorption of the olefin epoxide. Such catalysts are extremely active, selective, and stable under extended reaction conditions.
Keywords: Epoxidation; Silver; Molecular oxygen; Hydrogen peroxide; Titanium dioxide; Titanium silicalite; Propylene; Butadiene; Promoters; Gold; Palladium; Alkali promoters;

Catalysis in the preparation of fragrances and flavours by Christian Chapuis; Denis Jacoby (93-117).
This review, with more than 250 references in the field of fragrance and flavour chemistry, summarises recent progress in industrial catalysis. Applications in classical reactions, such as hydrogenations, isomerisations, hydride reductions, oxidations, hydroformylations, metathesis, aldol and Friedel–Crafts condensations in achiral, racemic and asymmetric fashion are discussed.
Keywords: Homogeneous; Heterogeneous; Catalyst; Catalysis; Industrial; Chiral; Asymmetric; Perfume; Fragrance; Flavour; Aroma; Review;

Enantioselective catalysis in fine chemicals production by H.U. Blaser; F. Spindler; M. Studer (119-143).
This review describes the state of the art for the application of enantioselective catalysts for the industrial production of enantiomerically enriched chiral fine chemicals. In a certain sense it is an up-date of an overview written by Scott 10 years ago . A comparison of the two articles reveals that certain aspects such as the difficulty to get precise information on industrial processes remained the same. As a consequence, many references relate to relatively informal sources such as C&EN, proceedings of commercial meetings and reviews. Other aspects, especially the state of the art in enantioselective catalysis but also the nature of the industrial players have changed significantly in the last decade. The present overview tries to cover all enantioselective catalytic processes that have been and/or still are used for the commercial manufacture of enantioenriched intermediates. In addition, we have also tried to get information on catalytic processes not (yet) used in actual production. Another goal of the review is to give the organic chemist working in process development an impression of the synthetic opportunities of enantioselective catalysis and to impart to the production manager some understanding of the potential problems when enantioselective processes are developed.After a short introduction to the world of chirality and enantioselective catalysis, the most important production methods for enantiopure chiral molecules are described. The relevant requirements for the application of enantioselective catalysis in fine chemicals production are then discussed in order to show what factors determine whether a catalytic method can be applied successfully or not. In the next paragraphs, the major industrial players in the field of enantioselective catalysis, existing processes in production and selected examples of processes in the bench scale and pilot stage are described. In a similar way, large scale ligands and chiral auxiliaries for enantioselective catalysis and their producers are tabulated and described.
Keywords: Enantioselective catalysis; Industrial processes; Chiral ligands; Asymmetric hydrogenation; Process development;

Enzyme-catalyzed processes in pharmaceutical industry by J.Peter Rasor; Edgar Voss (145-158).
Biocatalysis is enjoying an increasing interest not only in academia, but also in industry. It has been the topic of several excellent reviews or books [Bornscheuer and Kaszlauskas, Hydrolases in Organic Synthesis—Regio- and Stereoselective Biotransformations, Wiley-VCH, Weinheim, 1999; H.-J. Rehm, G. Reed, A. Pühler, P. Stadler (Eds.), Biotechnology, Biotransformations, Vol. 8, Wiley-VCH, Weinheim, 1998; Faber, Biotransformation, Organic Chemistry, Springer Berlin, 1996; K. Drauz, H. Waldmann, (Eds.), Enzyme Catalysis in Organic Synthesis, VCH Verlagsgesellschaft mbH, Weinheim, 1995; Wong and Whitesides, Enzymes in Synthetic Organic Chemistry, Tetrahedron Organic Chemistry, Vol. 12, Pergamon, Oxford, 1994; Sheldon, Chirotechnology, Marcel Dekker, New York, 1993; Chem. Today 13 (1995) 9; Drug Discovery Today 2 (1997) 513; Bioorg. Med. Chem. 7 (1999) 2253; J. Chem. Soc., Perkin Trans. 1 (1999) 1; U.T. Bornscheuer, in: Biotechnology—Biotransformations II, Vol. 8b, Wiley-VCH, Weinheim, 2000 pp. 277–294.] . Aim of this article is to present recent developments of biocatalysis in the pharmaceutical industry in a more didactical manner. An outlook on future aspects of biocatalysis will reflect the authors opinion. We will discuss the fundamental strength of biocatalysis but also some commonly held pre-conceptions, which we believe are superficial.
Keywords: Biocatalysis; Chemoselectivity; Regioselectivity; Enantioselectivity; Enantiomer; Processes;

Enzymatic catalysis in toxicologic pathology by U. Deschl; U. Bach (159-169).
Toxicological investigations are vital in the development of drugs and chemicals, in which enzymatic catalysis plays a key role for the visualization of the binding sites. It is for example used in techniques like immunohistochemistry or in situ hybridization (ISH), obtaining information on the protein and genetic level. In the immunohistochemistry tissue constituents are identified with a specific labeled antibody. During ISH specific nucleic acid RNA of DNA sequences are identified by complementary base pairing with labeled probe strands of RNA, DNA or oligonucleotides. For the latter technique, the procedure, probe molecules, possible enzymes and labeling methods and the sensitivity are discussed. Finally, the use of enzymatic catalysis in toxicologic pathology, for example, in carcinogenicity investigations or in oncology, is discussed.
Keywords: Enzymatic catalysis; Toxicology; Immunohistochemistry; In situ hybridization; Carcinogenicity; Oncology;

The membrane reactor in the fine chemicals industry by Jens Wöltinger; Karlheinz Drauz; Andreas S. Bommarius (171-185).
The enzyme-membrane reactor (EMR) is a well established mode for running continuous biocatalytic processes. One of Degussa’s strengths is expertise with EMRs on scales of five orders of magnitude, up to production scale of several hundred tons per year. In this article, an analogous chemzyme membrane reactor (CMR) is introduced. Current status with respect to relevant catalytic quantities such as turnover frequencies (TOFs), total turnover number (TTN), and catalyst half-life (τ 1/2) is discussed. First experiments with a pilot-scale CMR have been conducted. However, for easy scalability, more durable nanofiltration (NF) or ultrafiltration (UF) membranes as well as improved moisture control are necessary.
Keywords: Enzyme membrane reactor; Chemzyme membrane reactor; Turnover frequencies; Total turnover number; Catalyst half-life;

Commercial processes for manufacturing methylamines, C2–C5 alkylamines, cyclohexylamines, and DABCO are reviewed with emphasis on technology developments that have occurred during the last fifteen years. New technologies which have been explored include zeolite-catalyzed methylamines processes, direct amination of isobutylene to produce t-butylamine, and catalytic distillation for production of butylamines and cyclohexylamine. Opportunities for further process improvements are discussed.
Keywords: Amination; Reductive alkylation; Methylamines; Alkylamines; Cyclohexylamine; DABCO; Hydrogenation;

Nitrogen-containing compounds are used as structural components of pharmaceuticals and agrochemicals due to their high biological activities. There are many nitrogen-containing chemicals, from simple structured compounds as pyridine bases to complicated compounds as pharmaceutical ingredients and their number is growing rapidly year by year.Among the nitrogen containing compounds, pyridine bases are produced in by far the largest quantity and are used in various applications as herbicides, insecticides, vitamins like nicotinic acid and nicotinic acid amide, pharmaceuticals and adhesives. Pyrazines are used in flavors and fragrances and pharmaceutical intermediates. Among them, 2-methylpyrazine is used as a raw material of anti-tuberculosis drug, i.e. pyrazinamide. Pyrrole is used as a raw material of polypyrrole rather than in pharmaceutical applications. Polypyrrole has attracted much attention recently as an electroconductive polymer and its inexpensive production process is required.This article describes about such fundamental nitrogen-containing heterocyclic compounds as pyridine bases, pyrazines, piperidine, pyrrolydine, pyrrole, indole and imidazole.
Keywords: Heterocyclic compounds; Pyrazine; Polypyrrole;

The solid acid–base catalysts comprising of SiO2–X m –P n –O p (X: alkali metal, alkaline earth metal) showed high catalytic activity and selectivity in vapour phase intramolecular dehydration of monoethanolamine (MEA) to ethylenimine (EI). These catalysts have acid sites and basic sites that were controlled extremely week (+4.8<H0, H<+9.3). On the basis of the results obtained from pulse reaction carried out with these catalysts and TPD/IR measurements of the catalysts, the following mechanism is concluded. MEA is preferentially adsorbed from the side of the hydroxyl group, which is then dissociated on acid and base sites of the catalyst simultaneously, and the consecutive dehydration occurs to form EI. The newly developed vapour phase process using these catalysts has been operated in the commercial plant since 1990.
Keywords: Acid–base catalysis; Ethylenimine; Monoethanolamine;

Aqueous biphasic catalysis: Ruhrchemie/Rhône-Poulenc oxo process by Christian W. Kohlpaintner; Richard W. Fischer; Boy Cornils (219-225).
The use of water-soluble catalysts represents a significant advance in homogeneous catalysis in general and in the manufacture of n-butyraldehyde in special. Although catalyzed homogeneously, the technique of an “immobilized catalyst in mobile phase” offers all advantages of a heterogeneous process. Thus, the combination of homogeneous catalysis with heterogeneous catalyst handling yields the most straightforward and soundest oxo process with superior economics.
Keywords: Water-soluble catalysts; Hydroformylation; Oxo process;

In this article, the key issue of the catalysts for hydrogenation of aromatic and aliphatic carboxylic acids to the corresponding aldehydes was reviewed. For the hydrogenation of aromatic carboxylic acids, metal oxides, such as ZrO2, CeO2, ZnO and MnO, show high activity and selectivity to aldehydes. On the other hand, for aliphatic carboxylic acids which have two α-hydrogen atoms, these metal oxides show low selectivity for hydrogenation, because undesirable ketonization occurs. For the hydrogenation of aliphatic carboxylic acids, Cr2O3 and the partially reduced Fe2O3 show high selectivity. Especially, the highly pure Cr2O3 exhibits superior chemo-selectivity to aldehyde without CC bond migration or ketonization. The chromium-modified ZrO2 catalyst for manufacturing aromatic aldehydes and the highly pure Cr2O3 catalyst for manufacturing aliphatic aldehydes have been commercially used in industrial processes. A new aspect of direct hydrogenation catalysts is briefly reviewed, and the reaction mechanism for hydrogenation of carboxylic acids is also discussed.
Keywords: Hydrogenation catalysis; Zirconia; Chromia; Carboxylic acid; Aldehyde production; Hydrogenation mechanism;

Developments in the production and application of dimethylcarbonate by Daniele Delledonne; Franco Rivetti; Ugo Romano (241-251).
Manufacturing methods of dimethylcarbonate (DMC) are examined, in particular those which have been industrially exploited. Apart from the old phosgenation process, two processes based on the oxy-carbonylation of methanol went on stream: the copper chloride catalysed, one step liquid-phase process, by EniChem, and the palladium catalysed, two steps gas-phase process, via methylnitrite, by UBE. Two further technologies are attractive for full-scale development in the next future: the gas-phase direct methanol oxy-carbonylation and the alkylenecarbonate transesterification process. In the last few years, the use of DMC in the chemical industry has considerably grown, due to its chemical properties and its non-toxicity, an outstanding example being represented by the non-phosgene production of aromatic polycarbonates. Other very promising fields of large scale DMC application are as solvent and as oxygenate in reformulated fuels.
Keywords: Dimethylcarbonate; Manufacturing methods; Applications; Carbonylation;

Recent advances in processes and catalysts for the production of acetic acid by Noriyuki Yoneda; Satoru Kusano; Makoto Yasui; Peter Pujado; Steve Wilcher (253-265).
Novel acetic acid processes and catalysts have been introduced, commercialized, and improved continuously since the 1950s. The objective of the development of new acetic acid processes has been to reduce raw material consumption, energy requirements, and investment costs. At present, industrial processes for the production of acetic acid are dominated by methanol carbonylation and the oxidation of hydrocarbons such as acetaldehyde, ethylene, n-butane, and naphtha. This paper discusses advances in acetic acid processes and catalysts according to the following routes: (1) methanol carbonylation; (2) methyl formate isomerization; (3) synthesis gas to acetic acid; (4) vapor phase oxidation of ethylene, and (5) other novel technologies.
Keywords: Acetic acid; Methanol carbonylation; Hydrocarbon oxidation; Reaction mechanisms;

The phase-out of ozone-depleting chlorofluorocarbons (CFCs) has been a huge commercial success. The chemistry required to make replacement chemicals is very complex and new catalysts were required. In the early days of the development effort, yield and lifetime were serious concerns. Many of these problems have been solved and large volume plants are operating commercially. This short article will summarize the key improvements and discuss future research opportunities.
Keywords: Cholorofluorocarbons; Hydrodechlorination; Lewis acid;

Methanol technology developments for the new millennium by P.J.A Tijm; F.J Waller; D.M Brown (275-282).
This contribution to the “special issue” of Applied Catalysis A: General entitled “Industrial catalytic processes” deals with the development of the methanol process during the last 10–15 years. Following a brief review of the history, the developments to improve methanol synthesis are presented along the lines of elements of catalyst system improvements and of reactor improvements.
Keywords: Reactor; Pyrolysis; Synthesis gas;

Alkylation of aromatics with ethylene and propylene: recent developments in commercial processes by Thomas F. Degnan; C.Morris Smith; Chaya R. Venkat (283-294).
This paper provides an overview of current industrial alkylation processes for the production of ethylbenzene and cumene. In recent years, zeolite catalysts have begun to displace the conventional aluminum chloride and solid phosphoric acid (SPA) Friedel–Crafts catalysts used in both ethylbenzene and cumene processes. This transformation has been particularly rapid in the case of cumene technology, where more than 50% of the worldwide cumene capacity has converted to zeolite catalysts in the last 5 years.
Keywords: Industrial processes; Cumene; Ethylbenzene; Aromatics alkylation; Zeolites;

Production of linear alkylbenzenes by Joseph A Kocal; Bipin V Vora; Tamotsu Imai (295-301).
Linear alkylbenzene technology has almost completely replaced the older branched alkylbenzene technology for production of surfactants due to improved biodegradability and cost-effectiveness. The technology of choice today is dehydrogenation of n-paraffins to n-olefins followed by benzene alkylation to produce linear alkylbenzene. Solid acids catalyst-based systems are emerging to slowly replace hydrofluoric acid units in order to ensure environmental safety and improve economics. Numerous materials have been evaluated as solid acid catalysts for this alkylation process including zeolites, clays, various metal oxides, and supported aluminum chloride. At this time, only the UOP Detal technology has been commercialized. Because of ongoing fundamental studies on reaction mechanism and catalyst properties, significant progress is being made to improve the selectivity, catalytic stability, and long-term stability of these solid acids under commercial operating conditions.
Keywords: Detal technology; UOP; Alkylbenzenes;

Trends in industrial catalysis in the polyurethane industry by Gerhard Wegener; Matthias Brandt; Lothar Duda; Jörg Hofmann; Bert Klesczewski; Daniel Koch; Robert-Joseph Kumpf; Holger Orzesek; Hans-Georg Pirkl; Christian Six; Christian Steinlein; Markus Weisbeck (303-335).
Catalysis has been an important field for polyurethane chemistry and many improvements have been accomplished in recent years. Some of the greatest challenges however still remain. There is not yet a satisfactory catalytic way for the direct oxidation of propene to propene oxide in spite of ruthless activities by all major players over decades. New methods of catalysts screening and improved tools for catalyst characterization may help to solve this problem in the near future. Catalyst development in the area of polyether synthesis has recently opened new routes to completely new products. New raw materials may become attractive and new polyether polyol structures will be accessible with new catalysts. The range of new polymers will open up new opportunities. In the field of isocyanates the optimization of all manufacturing steps (nitration, hydrogenation, phosgenation) is an ongoing process since commercial production started an incremental improvements are accomplished and implemented constantly. Major improvements for existing processes, including all their catalytic reaction steps, are not to be expected in the near future. Significant improvements seem only possible by alternative ways of isocyanate manufacturing. In this area, catalytic reactions and the modern tools of catalysts research will play a key-role. However, as for all new developments, they will have only a chance on realization on a commercial scale, if they are economically competitive to well established processes.
Keywords: Industrial catalysis; Phosgenation; Polyurethane industry;

The development of the commercialization of 2,6-naphthalenedicarboxylic acid (2,6-NDA), dimethyl-2,6-naphthalenedicarboxylate (2,6-NDC) and their homopolymer with ethylene glycol, polyethylene naphthalate (PEN), is reviewed. Many of the significant alternative chemical routes to produce 2,6-dimethylnaphthalene (2,6-DMN), the main precursor to 2,6-NDA, are discussed and evaluated. The o-xylene+butadiene multi-step route of BP Amoco’s first-in-the-world large scale commercial plant built in Decatur, Alabama is described. Production economics of some of the major 2,6-NDC precursors are described. Physical properties of the 2,6-DMN intermediates, 2,6-NDA and 2,6-NDC, are given along with some discussion on the methods of purification of the dibasic naphthalate monomers. Polymer applications for PEN and manufacturing economics of PEN versus PET are compared, and finally, engineering resins incorporating 2,6-NDA and 2,6-NDC are described.
Keywords: 2,6-Dimethylnaphthalene (2,6-DMN); Polyethylene naphthalate (PEN); Dimethyl-2,6-naphthalenedicarboxylate (2,6-NDC); 2,6-Naphthalenedicarboxylic acid (2,6-NDA);

Two catalytic methods emerging newly for the production of ε-caprolactam are reviewed: the ammoximation, and the vapor phase Beckmann rearrangement. These processes do not produce any ammonium sulfate as a by-product. The key for the processes are the catalysts used. The TS-1 zeolite comprising Ti and Si oxides with the structure of MFI is applied as an effective catalyst in the ammoximation reaction. This work reviews its catalysis and the features of the reaction.Although many solid acid catalysts have been tested for the Beckmann rearrangement, recently high silica MFI zeolites without so-called acidic sites are developed for the reaction. A brief history of the catalyst development on the rearrangement is presented, and the catalysis of high silica MFI zeolite is reviewed.
Keywords: ε-Caprolactam; Cyclohexanone oxime; Ammoximation; TS-1; Vapor phase Beckmann rearrangement; High silica MFI zeolite;

Methyl methacrylate MMA can be produced in different ways based on C2C4 hydrocarbon feedstocks. In the present review, the recent commercialized and expected MMA technologies will be described and a comparison of these production routes is given. Thereby, the catalyst development will be strongly emphasized.
Keywords: Methyl methacrylate; Production; Hydrocarbons; Catalyst; Process;

Technologies for large-scale gas conversion by K Aasberg-Petersen; J.-H Bak Hansen; T.S Christensen; I Dybkjaer; P.Seier Christensen; C Stub Nielsen; S.E.L Winter Madsen; J.R Rostrup-Nielsen (379-387).
Indirect conversion of natural gas to liquid fuels via synthesis gas is more efficient than schemes presently known for direct conversion. Synthesis gas routes are capital intensive and hence there is a great interest in optimising process schemes based on steam reforming and autothermal reforming as well as exploring new principles for manufacture of synthesis gas. The paper reviews the requirements to the synthesis gas and the state-of-art of the technologies.
Keywords: Gas conversion; Steam reforming; Autothermal reforming;

New developments in FCC catalyst technology by R.H Harding; A.W Peters; J.R.D Nee (389-396).
Fluid catalytic cracking (FCC) is a central technology in refining. The present paper will focus on recent progress in FCC catalyst and process technology and will analyze the driving forces for such improvements. Thereby, the direct response to environmental regulations will become obvious. Another target of new developments has been to process heavier crude sources with higher levels of contaminants. Short contact time (SCT) cracking will also be discussed, reflecting significant developments in the reactor hardware.
Keywords: Fluid catalytic cracking; Zeolite; Catalyst;

Dehydrogenation and oxydehydrogenation of paraffins to olefins by M.M Bhasin; J.H McCain; B.V Vora; T Imai; P.R Pujadó (397-419).
Catalytic paraffin dehydrogenation for the production of olefins has been in commercial use since the late 1930s, while catalytic paraffin oxydehydrogenation for olefin production has not yet been commercialized. However, there are some interesting recent developments worthy of further research and development.During World War II, catalytic dehydrogenation of butanes over a chromia-alumina catalyst was practiced for the production of butenes that were then dimerized to octenes and hydrogenated to octanes to yield high-octane aviation fuel. Dehydrogenation employs chromia-alumina catalysts and, more recently, platinum or modified platinum catalysts. Important aspects in dehydrogenation entail approaching equilibrium or near-equilibrium conversions while minimizing side reactions and coke formation.Commercial processes for the catalytic dehydrogenation of propane and butanes attain per-pass conversions in the range of 30–60%, while the catalytic dehydrogenation of C10–C14 paraffins typically operates at conversion levels of 10–20%. In the year 2000, nearly 7 million metric tons of C3–C4 olefins and 2 million metric tons of C10–C14 range olefins were produced via catalytic dehydrogenation.Oxydehydrogenation employs catalysts containing vanadium and, more recently, platinum. Oxydehydrogenation at ∼1000 °C and very short residence time over Pt and Pt-Sn catalysts can produce ethylene in higher yields than in steam cracking. However, there are a number of issues related to safety and process upsets that need to be addressed. Important objectives in oxydehydrogenation are attaining high selectivity to olefins with high conversion of paraffin and minimizing potentially dangerous mixtures of paraffin and oxidant. More recently, the use of carbon dioxide as an oxidant for ethane conversion to ethylene has been investigated as a potential way to reduce the negative impact of dangerous oxidant–paraffin mixtures and to achieve higher selectivity.While catalytic dehydrogenation reflects a relatively mature and well-established technology, oxydehydrogenation can in many respects be characterized as still being in its infancy. Oxydehydrogenation, however, offers substantial thermodynamic advantages and is an area of active research in many fronts.
Keywords: Paraffin dehydrogenation; Olefin; Chromia-alumina catalyst; Paraffin oxydehydrogenation; Noble metal catalysts;

Isobutane alkylation by Sven Ivar Hommeltoft (421-428).
In the isobutane alkylation, alkylated gasoline is obtained which is a valuable blending component for the gasoline pool. Thereby the C3–C4 cut from the FCC units can be extensively used. Established technologies and recent developments will be reviewed and future perspectives will be given.
Keywords: Isobutane alkylation; FCC units; Future perspectives;

Lubricant base fluids based on renewable raw materials by Helena Wagner; Rolf Luther; Theo Mang (429-442).
Lubricants based on renewable raw materials and their derivatives are drawing increased attraction in various applications. Here, the environmental awareness is the key factor of success. The use of such rapidly biodegradable materials is especially favourable in loss-lubrication and hydraulic systems with increased risk of damage. Environmentally friendly, biodegradable alternatives are available for a large variety of mineral oil based lubricants. The substitution of mineral oil with biodegradable base oils is a primary objective. Vegetable oils are the major source of these base fluids. Compared to conventional mineral oil based fluids most of such substances exhibit lower thermal and oxidation stability and even worse low-temperature behaviour. These physical and chemical properties can be improved by chemical modification. This review covers chemical reactions performed on fatty compounds on both laboratory and industrial scale. Economic processes are presented as well as new reactions with potential market value. Alternative routes to improved rapidly biodegradable base fluids are mentioned too, e.g. breeding successes with high oleic sunflower oil.
Keywords: Renewable resources; Renewable raw material; Lubricants; Chemical modification; Vegetable oils; Oleochemicals; Biodegradable; Environmentally friendly; Base fluids; Sustainable materials;

Automobile exhaust catalysts by Ronald M. Heck; Robert J. Farrauto (443-457).
It has now been over 25 years since the introduction of the catalytic converter to reduce emissions from the internal combustion engine. It is considered one of the greatest environmental successes of the 20th century, however, new emission control technologies are still being developed to meet ever more stringent mobile source (gasoline and diesel) emissions. This short review will discuss the basis for improvements and highlight technology area, which will require further improvements in emissions and fuel economy. Some of the issues related to fuel cells which some believe may replace the internal combustion engines for automobile applications is also be briefly discussed.
Keywords: Catalytic converters; Gasoline; Diesel; Lean-burn engines; Lean-NO x ; Fuel cells;

Catalytic processes in solid polymer electrolyte fuel cell systems by Peter M. Urban; Anett Funke; Jens T. Müller; Michael Himmen; Andreas Docter (459-470).
Industrial application of fuel cell technology requires suitable electrocatalysts. This is true for all different types of fuel cells. These catalysts are responsible for the oxidation of the fuel (i.e. hydrogen, hydrogen rich gases or methanol) as well as for the oxygen reduction. This paper focuses on solid polymer electrolyte fuel cell systems for mobile applications. Here the demands on the catalyst are most severe due to the low-temperature operating regime. Two system configurations are possible: either the carbon containing fuel is processed by a fuel converter to a hydrogen rich gas mixture and this in turn is fed into the fuel cell. Alternatively fuels such as methanol can be supplied directly into the fuel cell. In the first case, contaminations of CO in the feed gas have to be taken into account. These strongly absorbs on the surface of the catalysts (carbon-supported Pt or Pt-alloys) thereby inhibiting the hydrogen oxidation reaction. Electro-oxidation mechanisms of adsorbed CO as well as methanol—as an example for a direct fuel cell system—is discussed on Pt-Ru and other catalysts. Finally catalysts for methanol and hydrocarbon reforming reactions as well as for the shift reaction are reviewed.
Keywords: Fuel cells; Solid polymer electrolyte fuel cell; Direct methanol fuel cell; Electrocatalysts;