Biopolymers from Renewable Resources is a compilation of information on the diverse and useful polymers derived from agricultural, animal, and microbial sources. The volume provides insight into the diversity of polymers obtained directly from, or derived from, renewable resources. The beneficial aspects of utilizing polymers from renewable resources, when considering synthesis, pro cessing, disposal, biodegradability, and overall material life-cycle issues, suggests that this will continue to be an important and growing area of interest. The individual chapters provide information on synthesis, processing and properties for a variety of polyamides, polysaccharides, polyesters and polyphenols. The reader will have a single volume that provides a resource from which to gain initial insights into this diverse field and from which key references and contacts can be drawn. Aspects of biology, biotechnology, polymer synthesis, polymer processing and engineering, mechanical properties and biophysics are addressed to varying degrees for the specific biopolymers. The volume can be used as a reference book or as a teaching text. At the more practical level, the range of important materials derived from renewable resources is both extensive and impressive. Gels, additives, fibers, coatings and films are generated from a variety of the biopolymers reviewed in this volume. These polymers are used in commodity materials in our everyday lives, as well as in specialty products."

The immobilized biocatalyst (IMB) is a key component of biotransformation systems that are used to transform substrates to desired products. The impro- ment of biocatalyst properties has a direct influence on the overall effectiveness of the process based on the biotransformation. The basic catalytic characte- stics of biocatalyst that are followed include kinetic properties, pH optima, stability,and inhibition. The investigation of catalytic properties of immobilized enzymes is still a time consuming procedure and is not always simple. In the 1980s,a major effort was made to standardize the rules by which IMB is char- terized. The Working Party of EFB on immobilized biocatalysts has formul- ed principles of individual methods, among them the requirement of kinetic characterization [1]. It was recommended to use a packed-bed reactor,equipped with temperature control and with infinite flow circulation. The system should be equipped with a post-column unit to measure the time-dependence of the product or substrate concentration [2, 3], the most commonly used analytical methods being spectrophotometry, chemiluminiscence, automatic titration, bioluminiscence, chromatography, polarimetry, and biosensors based on the oxygen electrode. There are two main drawbacks to the application of these methods: 1. The need to vary the analytical principles, depending on the chemical and physical-chemical properties of analytes; 2. In some cases, mainly in the study of hydrolytic enzymes, the natural s- strate must be replaced by an artificial one,that is chromolytic,chromogenic, chemiluminiscent,bioluminiscent,or fluorescent.

The Springer Handbook of Enzymes provides concise data on some 5,000 enzymes sufficiently well characterized - and here is the second, updated edition. Their application in analytical, synthetic and biotechnology processes as well as in food industry, and for medicinal treatments is added. Data sheets are arranged in their EC-Number sequence. The new edition reflects considerable progress in enzymology: the total material has more than doubled, and the complete 2nd edition consists of 39 volumes plus Synonym Index. Starting in 2009, all newly classified enzymes are treated in Supplement Volumes.

Plant secondary metabolism is an economically important source of fine chemicals, such as drugs, insecticides, dyes, flavours, and fragrances. Moreover, important traits of plants such as taste, flavour, smell, colour, or resistance against pests and diseases are also related to secondary metabolites. The genetic modification of plants is feasible nowadays. What does the possibility of engineering plant secondary metabolite pathways mean? In this book, firstly a general introduction is given on plant secondary metabolism, followed by an overview of the possible approaches that could be used to alter secondary metabolite pathways. In a series of chapters from various authorities in the field, an overview is given of the state of the art for important groups of secondary metabolites. No books have been published on this topic so far. This book will thus be a unique source of information for all those involved with plants as chemical factories of fine chemicals and those involved with the quality of food and ornamental plants. It will be useful in teaching graduate courses in the field of metabolic engineering in plants.

PART I - APPARATUS AND PRINCIPLES USED IN MICRODIFFUSION ANALYSIS - II. A STANDARD MICRO DIFFUSION APPARATUS OR 'UNIT' - III. FACTORS INFLUENCING THE ABSORPTION RATE FROM OUTER TO INNER CHAMBER WITH SPECIAL REFERENCE TO AMMONIA - IV. GENERAL PRINCIPLES GOVERNING THE ABSORPTION TIME IN MICRO DIFFUSION ANALYSIS - V. PIPETTES (SUITABLE FOR USE WITH THE STANDARD UNITS) AND THEIR DELIVERY ERRORS - VI. MICRO-BURETTES (SUITABLE FOR USE WITH THE STANDARD UNITS) AND ERRORS INVOLVED IN THEIR USE - VII. THE MICRODIFFUSION METHOD WITH END-POINT VOLUMES AROUND 20 CUBIC MILLIMETRES - VII. COLORIMETRY IN THE MICRODIFFUSION METHODS - PART II - DESCRIPTION OF METHODS WITH THE STANDARD UNITS - IX. AMMONIA. GENERAL METHOD USING STANDARD ACID AS ABSORBENT - X. AMMONIA. GENERAL METHOD (USING THE BORIC-HCL PROCEDURE) - XI. SPECIAL FACTORS INFLUENCING THE RATE OF AMMONIA ABSORPTION - XII. OTHER METHODS FOR DETERMINING THE ABSORBED AMMONIA IN THE MICRO DIFFUSION PROCEDURE - XIII. AMMONIA. BIOLOGICAL DETERMINATIONS - XIV. TOTAL NITROGEN XVII. UREA (BLOOD AND URINE) - XIX. ADENOSINETRIPHOSPHORIC ACID, ADENYLIC ACID, ADENOSINE, ETC. - XX. NITRATE, NITRITE AND AMIDE NITROGEN - XXII. MONOAMINE OXIDASE AND HISTAMINASE IN TISSUES - XXIII. DETERMINATION OF VOLATILE AMINES - XXIV. CARBONATES AND BICARBONATE - XXV. BLOOD GLUCOSE AND FERMENTABLE SUGAR IN NORMAL URINE - XXVI. DETERMINATION OF CARBONIC ANHYDRASE - XXVII. OXIDATION RATES OF ORGANIC SUBSTANCES WITH A STANDARD OXIDANT WITH APPLICATION TO DETERMINATION OF MINUTE AMOUNTS OF CALCIUM AS OXALATE - XXVIII. ACETIC ACID AND OTHER LOWER FATTY ACIDS - XXIX. ASSAY OF ACETYLCHOLINESTERASE - XXX. CYANIDE, AZIDE, SULPHIDE, PHENOLS - XXXI. METHANOL AND ISOPROPANOL GROUP - XXXII. ETHANOL - XXXIII. ETHANOL FROM URETHANE - XXXIV. FORMALDEHYDE - XXXV. FORMALDEHYDOGENIC STEROIDS (PERIODIC ACID AS OXIDANT) - XXXVI. FORMALDEHYDOGENIC STEROIDS (SODIUM BISMUTHATE AS OXIDANT) - XXXVII. GLYCINE (FORMALDEHYDE PRODUCED BY NINHYDRIN OXIDATION) - XXXVIII. ACETALDEHYDE (SEMICARBAZIDE ABSORPTION) - XXXIX. ACETALDEHYDE FROM LACTIC ACID AND THREONINE WITH BISULPHITE ABSORPTION - XL. ACETONE (INCLUDING A RAPID CLINICAL METHOD USING THE NESSLER SOLUTION) - XLI. THE HALOGENS (INTRODUCTORY) - XLII. CHLORIDE (BY OXIDATION TO CHLORINE AND ABSORPTION INTO IODIDE) - XLIII. CHLORIDE (BY OXIDATION TO CHLORINE AND ABSORPTION INTO FAST GREEN) - XLIV. BROMIDE - XLV. IODIDES AND HALOGEN MIXTURES - XLVI. SERIAL DETERMINATION OF ORGANICALLY BOUND HALOGEN - XLVII. VOLATILE HALOGENATED HYDROCARBONS (CHLOROFORM, TRICHLORETHYLENE AND CARBON TETRACHLORIDE) - XLVIII. CARBON MONOXIDE - XLIX. A RAPID CLINICAL METHOD FOR CARBON MONOXIDE DETERMINATION - LI. TOTAL MOLECULAR CONCENTRATION IN FLUID SAMPLES OF ABOUT 3-4 MILLIGRAMS - LII. SEPARATION OF CRYSTALS AND' GUMS' BY MICRODIFFUSION - QUALITATIVE MICRO-DIFFUSION ANALYSIS - LIII. SOME CONSIDERATIONS ON QUALITATIVE MICRO-DIFFUSION ANALYSIS - PART III - THE ERROR OF VOLUMETRIC TITRATION - LIV. INTRODUCTORY - LV. THE VARIABLE GLASS ERROR - LVI. THE TOTAL VARIABLE GLASS ERROR AND ITS CONTROL - LVII. THE VARIABLE CHEMICAL ERROR IN TITRATION - LVIII. THE RATIONALE OF MICRO TITRATION - LIX. THE CONSTANT GLASS ERROR - LX. THE CONSTANT CHEMICAL ERROR - LXI. VOLUMETRIC ERROR IN KJELDAHL NITROGEN ANALYSES - LXIII. UREA EXCRETION AS RENAL FUNCTION TEST - Full TOC available on website

The objective of the Springer Handbook of Enzymes is to provide in concise form data on enzymes sufficiently well characterized. Data sheets are arranged in their EC-Number sequence. Each volume comprises one enzyme class, sometimes the enzyme classes have to be divided into several volumes. Considerable progress has been made in enzymology since the publication of the first edition (published as "Enzyme Handbook"): many enzymes are newly classified or reclassified. In the 2nd edition each entry is correlated with references and one or more source organisms. New datafields are created: "application" and "engineering" (for the properties of enzymes where the sequence has been changed). Altogether the amount of data has doubled so that the 2nd edition will consist of 39 volumes plus synonym index. This collection is an indispensable source of information for researchers in biochemistry, biotechnology, organic and analytical chemistry, and food sciences.

There is hardly a technical library in the world in which the volumes of the Chemical Formulary (Volumes 1-34) do not occupy a prominent place. It does not duplicate any of the formulas included in previous volumes, but lists a wide array of modern and salable products from all branches of the chemical industries. An excellent reference for formulation problems. - CONTENTS - I. Introduction - II. Adhesives - III. Beverages and Foods - IV. Cosmetics - V. Coatings - VI. Detergents - VII. Drugs - VIII. Polishes - IX. Elastomers, Polymers and Resins - X. Miscellaneous - Appendix - Trademark Chemicals - Trademark Chemicals Suppliers - Index - PREFACE - Chemistry, as taught in our schools and colleges, concerns chiefly synthesis, analysis, and engineering-and properly so. It is part of the right foundation for the education of the chemist. Many a chemist entering an Industry soon finds that most of the products manufactured by his concern are not synthetic or definite complex compounds, but are mixtures, blends, or highly complex compounds of which he knows little or nothing. The literature in this field, if any, may be meager, scattered, or obsolete. Even chemists with years of experience In one or more Industries spend conslderable time and effort in acquainting themselves with any new field which they may enter. Consulting chemists similarly have to solve problems brought to them from industries foreign to them. There was a definite need for an up-to-date compilation of formulae for chemical compounding and treatment. Since the fields to be covered are many and varied, an editorial board of chemists and engineers engaged in many industries was formed. Many publications, laboratories, manufacturing firms, and Individuals have been consulted to obtain the latest and best information. It is felt that the formulas given in this volume will save chemists and allied workers much time and effort.

This title is Volume 2 of a 2 Volume set. - Contents - PART 1. - COMPOUNDED WAXES - 1. GENERAL - Compatibility - Hardness - Melting Point - Penetration - Refractive Index - Solubility in Oil - Viscosity - 2. PARAFFIN WAX COMPOUNDS - 3. ETHYL CELLULOSE AND WAX MIXTURES - Compounding Ethyl Cellulose with Incompatible Substances - Methods of Preparing Mixtures of Waxes with Ethyl Cellulose - 4. COMPOSITIONS WITH RESINS AND RUBBER - Resin Wax Compositions - Compatibility of Varnish Resins with Waxes - Cumarone-Indene Resins and Wax Compositions - Methacrylate Resin Hot-Melt Blends - Microcrystalline Wax-Resin Blends - Wax-Rubber Compositions - 5. COMMERCIAL WAX ADDITIVES - PART 2 - WAX TECHNOLOGY - 6. TESTS AND TECHNIQUES - The Melting' Points of Waxes - Odor and Taste - Emulsions - Fluorescence of Waxes - Solubility of Waxes - Commercial Wax Solutions - Surface Tension of Waxes - Specific Gravity - Specific Heat of Petroleum Waxes - To Alter Properties of Paraffin Wax - Simple Tests - Identification of Mixed Waxes - Separation and Comparison of Properties - Detecting Wax Additives - Evaluation of Waxes for Paperboard - Determinations of Properties - Testing for Quality Control - Opacifying Waxes - Coloring Waxes - 7. INDUSTRIAL USES OF WAXES - Adhesives - Candles - Coatings - Cosmetics - Electrical Applications - Inks - Leather Goods - Paper Products - Pharmaceutical Preparations - Photomechanics - Plastics - Polishes - Pyrotechnics - Rubber - Textile Processing - Abbreviations - Alphabetic Listing of Trademark Products - Index -

Rotary reactors or rotary kilns are the reactors facilitating the chemical reaction between the gas and solid phases usually at high temperatures.
This book, which is written by an expert in the field, describes the principles of the rotary reactor and the mode of its operation. These reactors are widely used in various chemical process industries (food, pharmaceuticals) and metallurgical industries.
The book defines the physiochemical aspects of the rotart reactors and provides theoretical equations of their operation.
The first part of this book presents the fundamentals; solid movement, conversion of solids, and heat transfer. The middle part of the book applies these equations to a variety of processes which have been developed so far, and shows how they are used. In its last part, conceptual designs of novel rotary reactors are proposed, which performance characteristics are predicted on the basis of above equations, especially, in gasification of solid wastes.
- Defines the rotary reactors and their mode of operation.
- Defines all operating parameters and gives equations to predict the operation of rotary reactors under various conditions.
- Includes a number of practical examples from various industrial applications (metallurgical waste treatment etc).

The Springer Handbook of Enzymes provides concise data on some 5,000 enzymes sufficiently well characterized - and here is the second, updated edition. Their application in analytical, synthetic and biotechnology processes as well as in food industry, and for medicinal treatments is added. Data sheets are arranged in their EC-Number sequence. The new edition reflects considerable progress in enzymology: the total material has more than doubled, and the complete 2nd edition consists of 39 volumes plus Synonym Index. Starting in 2009, all newly classified enzymes are treated in Supplement Volumes.

All important aspects of thermophilic moulds such as systematics, ecology, physiology and biochemistry, production of extracellular and intracellular enzymes, their role in spoilage of stores products and solid and liquid waste management, and general and molecular genetics have been dealt with comprehensively by experts in this book which covers progress in the field over the last 30 years since the seminal book Thermophilic Fungi published by Cooney and Emerson in 1964. The experts have reviewed extensive literature on all aspects of thermophilic moulds in a very comprehensive manner. This book will be useful for graduates as well as post-graduate students of life sciences, mycology, microbiology and biotechnology, and as a reference book for researchers.

This volume presents 12 comprehensive and timely review articles on some of the new tools and applications of biochemical engineering and biotechnology. The tools range from screening methods for novel biocatalysts and products, fluorescence spectroscopy and mass spectrometry for monitoring and analysis of cellular processes via mathematical models and protein expression systems for metabolic engineering to new bioreaction and separation devices. The applications cover the uses of animal and tissue cultures, insect cells, recombinant and marine microorganisms for the production of a variety of important bioproducts.

The objective of the Springer Handbook of Enzymes is to provide in concise form data on enzymes sufficiently well characterized. Data sheets are arranged in their EC-Number sequence. Each volume comprises one enzyme class, sometimes the enzyme classes have to be divided into several volumes. Considerable progress has been made in enzymology since the publication of the first edition (published as "Enzyme Handbook"): many enzymes are newly classified or reclassified. In the 2nd edition each entry is correlated with references and one or more source organisms. New datafields are created: "application" and "engineering" (for the properties of enzymes where the sequence has been changed). Altogether the amount of data has doubled so that the 2nd edition will consist of 39 volumes plus synonym index. This collection is an indispensable source of information for researchers in biochemistry, biotechnology, organic and analytical chemistry, and food sciences.

The idea of editing a book on modern software architectures and tools for CAPE (Computer Aided Process Engineering) came about when the editors of this volume realized that existing titles relating to CAPE did not include references to the design and development of CAPE software.
Scientific software is needed to solve CAPE related problems by industry/academia for research and development, for education and training and much more. There are increasing demands for CAPE software to be versatile, flexible, efficient, and reliable. This means that the role of software architecture is also gaining increasing importance. Software architecture needs to reconcile the objectives of the software; the framework defined by the CAPE methods; the computational algorithms; and the user needs and tools (other software) that help to develop the CAPE software. The object of this book is to bring to the reader, the software side of the story with respect to computer aided process engineering.

CONTENTS - INTRODUCTION - CHAPTER I: HYDROCARBONS - Benzene; Toluene; Xylene; Ethylbenzene; Cumene; Tetrahydronaphthalene; Decahydronaphthalene; Methylated naphthalenes; Coal tar solvent naphtha; Petroleum spirit; Benzine; White spirit; cycloHexane; Methylcyclohexane; Turpentine; Dipentene; cycloPentadiene; Dicyclopentadiene - CHAPTER II: CHLORINATED HYDROCARBONS - Methylene dichloride; Chloroform; Carbon tetrachloride; sym.-Dichloroethane; Tetrachloroethane; Pentachloroethane; Dichloroethylene; Trichloroethylene; Perchloroethylene; Propylene dichloride; Amyl chloride; Amylene dichloride; Monochlorobenzene; o-Dichlorobenzene - CHAPTER III: ALCOHOLS - Methyl alcohol; Wood spirit; Ethyl alcohol; n-Propyl alcohol; isoPropyl alcohol; n-Butyl alcohol; sec.-Butyl alcohol; isoButyl alcohol; tert.- Butyl alcohol; Amyl alcohol; Methylisobutylcarbinol; cycloHexanol; Methylcyclohexallo; Allyl alcohol; Benzyl alcohol; Diacetone alcohol; Ethylene chlorohydrin; Monochlorohydrin; Dichlorohydrin - CHAPTER IV: ETHERS - Ethyl ether; betabeta' -Dichloroethyl ether; isoPropyl ether; Propylene oxide; Dioxan; Methylal; Acetal; Paraldehyde - CHAPTER V: ESTERS - Methyl formate; Ethyl formate; n-Butyl formate; Amyl formate; Benzyl formate; Methyl acetate; Ethyl acetate; n-Propyl acetate; isoPropyl acetate; n-Butyl acetate; sec.-Butyl acetate; isoButyl acetate; Amyl acetate; sec.- Hexyl acetate; cycloHexyl acetate; Methylcyclohexyl acetate; Butoxyl; Benzyl acetate; n-Butyl propionate; Amyl propionate; n-Butyl butyrate; Methyl benzoate; Ethyl benzoate; Ethyl lactate; Butyl lactate; Amyl lactate; Ethyl hydroxyisobutyrate; Diethyl carbonate; Dialkyl carbonates; Diethyl oxalate - CHAPTER VI: KETONES - Acetone; Methyl acetone; Acetone oils; Methyl ethyl ketone; Methyl isobutyl ketone; Mesityl oxide; cycloHexanone; Methylcyclohexanone; Isophorone - CHAPTER VII: GLYCOLS AND THEIR DERIVATIVES - Ethylene glycol; Ethylene glycol mono-methyl ether; Ethylene glycol monoethyl ether; Ethylene glycol monoethylether monoacetate; Ethylene glycol diethyl ether; Ethylene glycol mono-n-butyl ether; Ethylene glycol monoacetate; Ethylene glycol diacetate; Diethylene glycol mono ethyl ether; Diethylene glycol mono-n-butyl ether; Diethylene glycol monoacetate; Dipropylene glycol - CHAPTER VIII: AMINES AND COAL TAR BASES - cycloHexylamine; Dicyclohexylamine; Ethanolamines; Pyridine; Picoline - CHAPTER IX: NITRO-COMPOUNDS - Nitromethane; Nitropropanes; Nitrobutanes; Nitrobenzene - CHAPTER X: MISCELLANEOUS COMPOUNDS - Carbon disulphide; Acetic acid; Acetic anhydride; Cresols; Dimethyl sulphate; Silicones and silane intermediates -

This book is a teaching aid as well as a practical guide for soil analysts. It is the result of twenty years of experience and study and analysis of soils. It is equally useful to the undergraduate, post-graduate student of soil sciences as well as for the research professional in the soil laboratory.

This thesis reports studies on the substrate specificity of crucial ketosynthase (KS) domains from trans-AT Polyketide Synthases (PKSs). Using a combination of electrospray ionisation-mass spectrometry (ESI-MS) and simple N-acetyl cysteamine (SNAC) substrate mimics, the specificity of a range of KS domains from the bacillaene and psymberin PKSs have been succsessfully studied with regard to the initial acylation step of KS-catalysis. In addition, the ability to alter the substrate tolerance of KS domains by simple point mutations in the active site has been demonstrated. A series of acyl-ACPs have been synthesised using a novel methodology and employed to probe the substrate specificity of both KS domains and the previously uncharcterised acyl hydrolase domain, PedC. KS-catalysed chain elongation reactions have also been conducted and monitored by ESI-MS/MS. All KS domains studied exhibited higher substrate specificity at the elongation step than in the preceeding acylation step. Furthermore, a mechanism of reversible acylation is proposed using the PsyA ACP1-KS1 di-domain. The findings in this thesis provide important insights into mechanisms of KS specificity and show that mutagenesis can be used to expand the repertoire of acceptable substrates for future PKS engineering.

Adaptive Internal Model Control is a methodology for the design and analysis of adaptive internal model control schemes with provable guarantees of stability and robustness. Written in a self-contained tutorial fashion, this research monograph successfully brings the latest theoretical advances in the design of robust adaptive systems to the realm of industrial applications. It provides a theoretical basis for analytically justifying some of the reported industrial successes of existing adaptive internal model control schemes, and enables the reader to synthesise adaptive versions of their own favourite robust internal model control scheme by combining it with a robust adaptive law. The net result is that earlier empirical IMC designs can now be systematically robustified or replaced altogether by new designs with assured guarantees of stability and robustness.

This title is Volume 1 of a 2 Volume set. - Contents - Introduction - Abbreviations - PART 1. NATURAL WAXES - 1. PARAFFIN WAX - Occurrence in Nature - Composition of Petroleum - Grades of Paraffin Wax - Manufacture of Paraffin Waxes - Composition of Paraffin Waxes - Properties of Paraffin Waxes - Wax-Oil Mixtures - Miscellaneous Data - Physical Properties of Some Commercial Waxes - 2. MICROCRYSTALLINE WAXES - Differences Between Microcrystalline and Paraffin Waxes - Fractional Crystallization of Petroleum Waxes - Properties of Microcrystalline Waxes - Oxidized Microcrystalline Waxes - Petrolatum - Uses of Microcrystalline Waxes - Miscellaneous Data - Properties of Some Commercial Microcrystalline Waxes - 3. OTHER MINERAL WAXES - Montan Wax - Lignite Wax - Ozocerite - Ceresin - Utah Wax - Peat Wax - 4. VEGETABLE WAXES - Bayberry - Candelilla - Carnauba - Cotton - Esparto - Fir - Japan - Ouricury - Palm - Rice-Oil - Sugar Cane - Ucuhuba - Cocoa Butter - 5. ANIMAL WAXES - Beeswax - Chinese Wax - Shellac Wax - Spermaceti - Wool Wax - PART 2. : SYNTHETIC WAXES 6. FATTY ALCOHOLS AND ACID - Cetyl Alcohol - Lanette Wax - Stearyl Alcohol - Stearic Acid - Palmitic Acid - Myristic Acid - 7. FATTY ACID ESTERS AND GLYCERIDES - Glyceryl Stearates - Glycol Fatty-Acid Stearates - Sorbitol Stearates - Polyethylene Glycol Stearates - Properties of Selected Commercial Products - 8. HYDROGENATED OILS - Properties of Selected Commercial Products - 9. KETONES, AMINES, AMIDES - Stearone, Laurone - Aliphatic Amines - Aliphatic Amides - Properties of Some Commercial Products - 10. CHLORONAPHTHALENES - 11. SYNTHETIC MINERAL WAXES - Fisher-Tropsch Waxes - Duroxon Waxes - 12. SYNTHETIC ANIMAL WAXES - Synthetic Beeswax - Modified Spermaceti Waxes - Modified Lanolin Waxes - 13. MISCELLANEOUS SYNTHETIC WAXES - Oxazoline - Experimental Waxes -

Zeolites occur in nature and have been known for almost 250 years as alumino silicate minerals. Examples are clinoptilolite, mordenite, offretite, ferrierite, erionite and chabazite. Today, most of these and many other zeolites are of great interest in heterogeneous catalysis, yet their naturally occurring forms are of limited value as catalysts because nature has not optimized their properties for catalytic applications and the naturally occurring zeolites almost always contain undesired impurity phases. It was only with the advent of synthetic zeolites in the period from about 1948 to 1959 (thanks to the pioneering work of R. M. Barrer and R. M. Milton) that this class of porous materials began to playa role in catalysis. A landmark event was the introduction of synthetic faujasites (zeolite X at first, zeolite Y slightly later) as catalysts in fluid catalytic cracking (FCC) of heavy petroleum distillates in 1962, one of the most important chemical processes with a worldwide capacity of the order of 500 million t/a. Compared to the previously used amorphous silica-alumina catalysts, the zeolites were not only orders of magnitude more active, which enabled drastic process engineering improvements to be made, but they also brought about a significant increase in the yield of the target product, viz. motor gasoline. With the huge FCC capacity worldwide, the added value of this yield enhancement is of the order of 10 billion US $ per year."