bluuebunny/crossref_metadata_2025 huggingface dataset:
Benzyl Alcohol and β‐Phenethyl Alcohol
Authors: Mookherjee Braja D. , Wilson Richard A.
Published: July 2004

Benzyl alcohol and β‐phenethyl alcohol (2‐phenylethanol) are the simplest of the aromatic alcohols, and, as such, are chemically similar. Benzyl alcohol occurs widely in essential oils both as the free alcohol, and, more importantly from a fragrance standpoint, in the form of various esters. Although benzyl alcohol itself is rather bland in odor, combined with its much more fragrant esters it is an important part of the odor of jasmine, ylang‐ylang, gardenia, some rose varieties, narcissus and peony, as well as castoreum, balsams of peru and tolu, and propolis. Benzyl alcohol occurs primarily in flower oils and tree exudates. Benzyl alcohol readily undergoes the reactions characteristic of a primary alcohol, such as esterification and etherification, as well as halide formation. In addition, it undergoes ring substitution. Today benzyl alcohol is almost universally manufactured from toluene which is first chlorinated to give benzyl chloride. This is then hydrolyzed to benzyl alcohol by treatment with aqueous sodium carbonate. In the soap, perfume, and flavor industries benzyl alcohol is primarily used in the form of its aliphatic esters. Benzyl alcohol is commercially available in five grades. The largest proportion of benzyl alcohol is for use in the photographic and textile industries although the latter use has been declining. The textile grade is used as a dyeing assistant for wool and nylon. The pharmaceutical industry makes use of benzyl alcohol's local anesthetic, antiseptic, and solvent properties. The technical grade of benzyl alcohol is used in rug cleaners as a degreasing agent, in leather dyeing, in ballpoint inks, as a cleaner for soldering, and as an extractive distillation solvent for xylenes and cresols. In addition, benzyl alcohol is used extensively in the polymer industry and in the manufacture of automobile tires. This material has a Generally Recognized As Safe (GRAS) status indicated by the Flavor and Extract Manufacturers' Association for use in flavors and by the Council of Europe for use as a flavor. Benzyl alcohol satisfies the most current guidelines published by the International Fragrance Association (IFRA). Of all the aromatic organic molecules β‐phenethyl alcohol (PEA) is probably the most prestigious aroma chemical in the world of perfumery. This is because of its exquisite odor of natural rose petals. The compound undergoes the usual chemical reactions of alcohols or aromatic compounds. In insect control, PEA has been considered as a mosquito repellant. The alcohol also has antifungicidal properties. Because of factors of low cost, stability, and odor quality, PEA is ideally suited for use in bar soap fragrances. Current commercial methods for making PEA include Grignard synthesis, Friedel‐Crafts process, and catalytic hydrogenation of styrene oxide. Approximately 85% of the PEA is employed for fragrance use. The use of β‐phenethyl alcohol generally presents no health problems.
Benzaldehyde
Authors: Opgrande Jarl L. , Brown Edward , Hesser Martha , Andrews Jerry
Published: July 2004

Benzaldehyde is the simplest and quite possibly the most industrially useful aromatic aldehyde. It is manufactured from toluene, either by chlorination, followed by hydrolysis, or by liquid phase air oxidation. The air oxidation of toluene to produce benzoic acid is the source of most of the world's synthetic benzaldehyde.

Benzaldehyde is widely used directly, as a synthetic flavoring substance, or as a raw material in the synthesis of industrially important derivatives such as benzyl alcohol, benzoin and benzil and several benzyl amines. The hydrogenation of benzaldehyde to form benzyl alcohol is the largest single use of benzaldehyde.

In addition, benzaldehyde serves as the major raw material a wide variety of fragrance compounds are derivatives of benzaldehyde. The major products in the fragrance category are cinnamic aldehyde and a number of substituted cinnamic aldehydes; such as methyl, butyl, amyl, and hexyl cinnamic aldehydes.
Benzoic Acid
Authors: Opgrande Jarl L. , Brown Edward E. , Hesser Martha , Andrews Jerry
Published: July 2004

The simplest member of the aromatic carboxylic acid family, benzoic acid was first described in the 17thcentury and initially used extensively as a medicinal substance. Currently the main uses for benzoic acid are as a chemical additive in alkyd resins and as a raw material in the manufacture of phenol, caprolactam, glycol dibenzoate plasticizer esters, and in the production of the food preservatives, sodium and potassium benzoates.

The liquid phase air oxidation of toluene provides most of the world's supply of benzoic acid. Large quantities of benzaldehyde can be recovered in the same process.

Other major derivatives of benzoic acid include benzoyl chloride, benzoic anhydride, and a number of benzyl esters, used in fragrances and personal care products. These include methyl, ethyl, butyl and hexyl benzoate as well as alkyl (C12‐15) benzoate.
Bioremediation
Authors: Prince Roger C.
Published: July 2004

Bioremediation seeks to use biological processes to restore contaminated environments to productive use. Many contaminants at industrial, agricultural, and accident sites are amenable to bioremediation. Most organic contaminants are biodegradable under some conditions, and optimizing this biodegradation is the principal thrust of bioremediation to date. Widely used treatments for hydrocarbons include the addition of oxygen or alternative electron acceptors, and the provision of limiting nutrients such as nitrogen and phosphorus. More recalcitrant organic contaminants, such as some halogenated products and some pesticides, herbicides and explosives, require more sophisticated approaches. These have included the addition of co‐substrates to stimulate the growth of degrading organisms, various treatments to increase the bioavailability of the contaminants, and sequential anaerobic and aerobic degradation. Inorganic contaminants are also amenable to bioremediation, since they may be sequestered or extracted from soils and waters by microbes and plants. Bioremediation competes in the marketplace with a range of chemical and physical treatments for cleaning contaminated sites and waters; in general bioremediation is among the least expensive and most benign, but also one of the slowest options.
Bioseparations
Authors: Ladisch Michael R.
Published: July 2004

The large scale purification of proteins and other bioproducts is the final production step, prior to product packaging, in the manufacture of therapeutic proteins, specialty enzymes, diagnostic products, and value added products from agriculture. These separation steps purify biological molecules or compounds obtained from biological sources, and hence, are referred to as bioseparations. The essence of large scale bioseparations is both art and science. Bioseparations often evolve from laboratory‐scale techniques. These are adapted and scaled up to satisfy the need for larger amounts of extremely pure, test quantities of the product for analysis, characterization, testing of efficiency, clinical or field trials, and finally, full‐scale commercialization. The uncompromising standards for product quality, driven by commercial competition, end‐use applications, and regulatory oversight, provide many challenges to the scale‐up of protein purification. The rigorous quality control of manufacturing practices embodied in current good manufacturing practices, and the complexity and lability of the macromolecules being processed provide other practical issues which must be addressed.

This article gives an overview of manufacturing approaches for selected bioproducts by the new biotechnology and how these approaches impact their recovery and purification using various bioseparation techniques. The basic theory of the most prevalent bioseparations method, chromatography, is described. Since the literature has presented the theory principally for analytical systems, application which are useful in scaling up process chromatographic separations are reviewed here. Also the reader is provided with practical tools that can be used to initiate the scale‐up of liquid chromatography starting from a minimum amount of laboratory data. The use and mechanisms of action of selected bioproducts are summarized to illustrate how recombinant biotechnology provides unique tools and facilitates new products which could not be obtained by other means.
Aeration, Biotechnology
Authors: Nienow Alvin W.
Published: July 2004

The supply of oxygen to a growing biological species, aeration, in aerobic bioreactors is one of the most critical requirements in biotechnology. Aeration is usually accomplished by transferring oxygen from the air into the fluid surrounding the biological species, from where it is in turn transferred to the biological species itself. During the course of a batch bioreaction, oxygen demand often passes through a marked maximum when the species is most biologically active. The main reason for the importance of aeration lies in the limited solubility of oxygen in water. The basic principles that underlie oxygenation (aeration) are exactly the same as those that determine the rate of transfer of any sparingly soluble gas (oxygen) from the gas stream (air) to the unsaturated liquid (broth). The rate at which this transfer takes place is dependent on the area of contact between the gas and the liquid, the driving force available (ie, the difference in concentration of oxygen in the two phases), the two‐phase fluid dynamics, and the chemical composition of the liquid. A huge variety of bioreactors have been developed; a useful subdivision has been made into three generic types. These are bioreactors driven by rotating agitators (stirred tanks) that are by far the most common, bioreactors driven by gas compression (bubble columns/loop fermenters), and bioreactors driven by circulating liquid (jet loop reactors). Aeration is used in bacterial, aerobic yeast, polysaccharide and mycelial fermentations, mammalian and plant cell culture, single‐cell protein production, and biological aerobic wastewater treatment.
Biotin
Authors: Outten Robert A.
Published: July 2004

Biotin is a water‐soluble B complex vitamin originally isolated from a variety of natural sources. In biological systems, biotin functions as a cofactor for enzymes involved in carboxylation reactions. A lack of biotin results in deficiency diseases in humans and animals. Daily intakes of biotin are recommended in the maintenance of optimal health. Several synthetic pathways to biotin have been developed since its stereochemical determination. The modern industrial synthesis is based on work done by researchers in the late 1940s. Since this work, industrial research has been directed toward process improvements in the basic methodology, particularly in the area of methods to form optically pured‐lactone. Research has also been directed toward elucidation of the biosynthetic pathway to biotin. Various microorganisms have been evaluated for use in biotin synthesis via fermentation. Recently, a number of patents have appeared on the synthesis of biotin using biotechnology. Several analytical methods, including microbiological, chemical, and chromatographic assays, are used to determine biotin levels in food and body fluids.
Blood Coagulation and Anticoagulant Drugs
Authors: Walenga Jeanine M. , Jeske Walter P. , Bacher Peter , Fareed Jawed
Published: July 2004

The process of blood coagulation is not a simple transformation of fibrinogen to fibrin by the action of thrombin. Rather, this remarkably complex process is a result of numerous transformations mediated by enzymes, activators, inhibitors, platelets, endothelial cells, and leukocytes. Newer studies have also shown that some hemostatic responses are regulated through autonomic control mechanisms. Congenital abnormalities, acquired risk factors, medical procedures, and surgical interventions produce stimuli for hemostatic activation. These conditions necessitate the use of anticoagulant and antithrombotic agents to maintain blood fluidity. Heparin, an anticoagulant that possesses a complex mode of action, has been the only drug available to control thrombosis for many years. Low molecular weight heparin represents a refined and more optimized heparin where the pharmacokinetics and safety have been improved. Vitamin K antagonists are the only drugs available for long‐term anticoagulation. Understanding of the hemostatic activation processes, as well as appreciation for the importance of hemostasis in health, has occurred only recently and discoveries still continue. This has led to the development of newer pharmacologic approaches to inhibit and control thrombosis. Synthetic heparin‐derived drugs (fondaparinux), thrombin inhibitors, and antiplatelet drugs, have recently become available. The near future should bring factor Xa inhibitors, other coagulation protease inhibitors, additional antiplatelet drugs, non‐heparin drugs, and oral formulations. Because of the high morbidity–mortality associated with cardiovascular disease (thrombosis), it will be important to continue the development toward optimized antithrombotic drugs targeted to specific mechanisms with improved pharmacologic properties.
Boron Halides
Authors: Alam Fazlul , Evans Francis , Mani Ganpat , Papcun John R.
Published: July 2004

The boron trihalides boron trifluoride, BF3, boron trichloride, BCl3, and boron tribromide, BBr3, are important industrial chemicals having increased usage as Lewis acid catalysts and in chemical vapor deposition (CVD) processes. Boron halides are widely used in the laboratory as catalysts and reagents in numerous types of organic reactions and as starting material for many organoboron and inorganic boron compounds. Reactions of boron trihalides that are of commercial importance are those of BCl3and, to a lesser extent, BBr3, with gases in chemical vapor deposition (CVD). Boron trichloride is prepared on a large scale by the reaction of Cl2and a heated mixture of borax,, and crude oil residue in a rotary kiln heated to 1038°C. Boron trihalides, BX3, are trigonal planar molecules which are (sp)2hybridized. The X–B–X angles are 120°. The boron trihalides are strong Lewis acids; however, the order of relative acid strengths,, is contrary to that expected based on the electronegativities and atomic sizes of the halogen atoms. Boron tribromide is produced on a large scale by the reaction of Br2and granulated B4C at 850–1000°C or by the reaction of HBr with CaB6at high temperatures. Approximately 75–95% of the BCl3consumed in the United States is used to prepare boron filaments by CVD. Another important use of BCl3is as a Friedel‐Crafts catalyst in various polymerization, alkylation, and acylation reactions, and in other organic syntheses. BCl3is also used for the production of halosilanes, in the preparation of many boron compounds and in the production of optical wave guides. BBr3is used in the manufacture of isotopically enriched crystalline boron, as a Friedel‐Crafts catalyst in various polymerization, alkylation, and acylation reactions, and in semiconductor doping and etching. Boron subhalides are binary compounds of boron and the halogens, where the atomic ratio of halogen to boron is less than 3. The boron monohalides and boron dihalide radicals have been studied. Diboron tetraflouride, B2F4, diboron tetrachloride, B2Cl4, diboron tetrabromide, B2Br4, and diborontetraiodide, B2I4, are well‐known but thermally unstable compounds.

Fluoroboric acid and the fluoroborates are commercially important to a variety of industries. The acid is used in plating circuits, in metal finishing, in the production of aluminum, and as an acid catalyst. Main group metal and ammonium fluoroborates find use as fluxes, as catalysts, and in flame‐retardant manufacture. Transition‐ and other heavy‐metal fluoroborate salts are used in the plating industry and as catalysts. Properties and manufacture are described.
Hormones, Brain Oligopeptides
Authors: Childers Steven R.
Published: July 2004

Oligopeptides exist in mammalian brain in a variety of forms, and represent the most numerous of the neurotransmitter and neuromodulator candidates. Most of these peptides are relatively small, ranging from three to approximately 40 amino acids in length. As such, they are relatively simple to synthesize in the laboratory using solid‐phase peptide synthesis. Such syntheses have produced large numbers of analogues that are more potent or more stable than the native peptides, or may be specific antagonists at the peptide receptors. All of these neuropeptides are derived from large molecular weight protein precursors, which are cleaved into active products by the action of specific proteases. Many of the native peptides are extraordinarily potent in affecting different aspects of brain function, and have been implicated in central nervous system (CNS) disorders involving areas like Alzheimer's disease, control of appetite, clinical depression, and pain. A brief discussion of the various groups of brain oligopeptides is presented.
Bromotrifluoroethylene
Authors: Elliott Arthur J.
Published: July 2004

Bromotrifluoroethylene is a colorless gas that is spontaneously flammable in air and polymerizes at room temperature unless inhibited. It undergoes reactions typical of fluorinated olefins, including halogenation and hydrogenation, and addition of nucleophiles such as alkoxides. It is conveniently prepared in good yield in four steps starting with chlorotrifluoroethylene. Bromotrifluoroethylene is a valuable reagent for the synthesis of trifluorovinylic compounds by means of its intermediate organometallic compounds. Its homopolymer and several copolymers have been reported but find no commercial utility. However, telomers of bromotrifluoroethylene are useful as flotation and damping fluids for gyroscopes and accelerometers in inertial guidance systems. These fluids are expensive but are made in small volume for the aerospace industry.
Bromine
Authors: Grinbaum Baruch , Freiberg Mira
Published: July 2004

Diatomic bromine, Br2[7726‐95‐6], is the only nonmetallic element that is a liquid at standard conditions. Bromine is widely distributed in nature but in relatively small amounts, mainly as soluble bromide salts. It occurs in the form of bromide in seawater and in natural brine deposits, always together with chloride. Its concentration ranges from 65 mg/L in seawater up to 6.5 g/L in the Dead Sea and was discovered in 1826. Historically it has been important as an agent for removal of lead from combustion chambers. Nowadays, an important use of bromine compounds is in the production of flame retardants and drilling fluids, and as a component in intermediates for pharmaceutical, biocide and photographic industry, dyes, disinfectants, water treatment, and so on. Bromine is a heavy liquid, hardly soluble in water. It tends to acquire an electron to form either a negative ion, Br−, or a single covalent bond, Br. Nonmetal bromides are generally hydrolyzed to a hydrogen halide and to an oxy‐acid containing the other element. Bromine combines directly with hydrogen at elevated temperatures, when this is the basis for the commercial production of hydrogen bromide. Bromine reacts with essentially all metals, except tantalum and niobium, and also with some metal oxides. The addition of bromine to unsaturated carbon compounds occurs readily. In alkaline solution, bromine reacts rapidly to produce hypobromite. In all current methods of bromine production, chlorine, which has a higher reduction potential than bromine, is used to oxidize bromide to bromine. The price of bromine is ∼ 1.3 $/kg. The annual worldwide production is > 500,000 ton and growing slowly, with the United States and Israel as the leading manufacturers. Bromine is highly toxic and corrosive, and utmost care should be taken when handling it.
Magnetic Materials, Bulk
Authors: Wernick Jack
Published: July 2004

Magnetism is classified according to the nature of the bulk magnetic response in a magnetic field. Types of magnetism are defined as are the terms of magnetic behavior. Bulk magnetic materials may be classified as either soft or hard. The important soft magnetic materials, characterized by high permeability and low coercivity, include iron and low carbon steel, iron–silicon alloys, iron–aluminum and iron–aluminum–silicon alloys, cobalt–iron (Permendurs) and nickel–iron alloys (Permalloys), ferrites, and amorphous magnetic alloys. The iron‐based alloys are used for power distribution transformers and magnetic shielding. The ferrites are used at high frequencies for inductors and communication transformers as well as for microwave devices. Moreover, the use of MnZn ferrite cores in power transformers is increasing rapidly.

The hard of permanent magnet materials are characterized by high coercivity and high energy product. Materials in use include the hexagonal barium and strontium ferrites, alnicos, the modified binary cobalt‐base intermetallics containing rare earths, and the ternary neodynium iron‐base intermetallics. Motors, loudspeakers, and disk drives are the largest consumers of hard magnetic materials. The exceptionally large values of maximum energy products and coercivities of the Nd–Fe–B magnets permit use in devices where small size and superior performance are desired. Many of the semihard permanent magnet materials are sufficiently ductile for forming into requisite shapes. Information is presented for several important materials which can be cold formed, rolled to thin foil, and can be stamped into precision parts at high speeds.
Butyraldehydes
Authors: Billig Ernst
Published: July 2004

The two isomeric butanals,n‐ and isobutyraldehyde, C4H8O, are produced commercially almost exclusively by the Oxo reaction of propylene. They also occur naturally in trace amounts in tea leaves, certain oils, coffee aroma, and tobacco smoke. The butanals are highly flammable, colorless liquids of pungent odor. These aldehydes are miscible with most organic solvents, eg, acetone, ether, ethanol, and toluene, but are only slightly soluble in water. The reactions ofn‐ and isobutyraldehyde are characteristic aldehyde reactions of oxidation, reduction, and condensation. The majority of the butyraldehyde produced in the United States is converted into 1‐butanol and 2‐ethylhexanol (2‐EH). The remainingn‐butyraldehyde production of the United States goes into (in decreasing order): poly(vinyl butyral), 2‐ethylhexanal, trimethylolpropane, methyl amyl ketone, and butyric acid. A large portion of the total U.S. consumption of isobutyraldehyde goes into the production of isobutyl alcohol and isobutyraldehyde condensation and esterification products. The other principal isobutyraldehyde derivative markets are neopentyl glycol, isobutyl acetate, isobutyric acid, isobutylidene diurea, and methyl isoamyl ketone. The merchant market for the two aldehydes is relatively insignificant, most of the production being employed captively. The most activen‐butyraldehyde derivatives were expected to be PVB, as more regions require automotive safety glass, and trimethylolpropane. Although tests have shown thatn‐butyraldehyde causes some adverse physiological effects, there is no danger to health in normal plant practice. Both aldehydes have a pungent, penetrating odor. Their vapors as well as the neat liquids can cause skin, eye, and respiratory organ irritation. Stainless steel, baked phenolic‐lined steel, or aluminum are often used for storage and handling ofn‐ and isobutyraldehyde. Storage of the aldehydes under nitrogen preserves the integrity of the material.
Butylenes
Authors: Calamur Narasimhan , Carrera Martin E. , Wilsak Richard A.
Published: July 2004

Butylenes are C4H8mono‐olefin isomers: 1‐butene,cis‐2‐butene,trans‐2‐butene, and isobutylene (2‐methylpropene). These isomers are usually coproduced as a mixture and are commonly referred to as the C‐4 fraction. These C‐4 fractions are usually obtained as by‐products from petroleum refinery and petrochemical complexes that crack petroleum fractions and natural gas liquids. Since the C‐4 fractions almost always contain butanes, it is also known as the B–B stream. The linear isomers are referred to as butenes. The carbon–carbon double bond is the distinguishing feature of the butylenes and, as such, controls their chemistry. The carbon–carbon bond, acting as a substitute, affects the reactivity of the carbon atoms at the alpha positions through the formation of the allylic resonance structure. This structure can stabilize both positive and negative charges. Reactions of butylenes can be divided into two broad categories: those that take place at the double bond itself, destroying the double bond; and those that take place at alpha carbons. The C‐4 isomers are almost always produced commercially as by‐products in a petroleum refiner–petrochemical process. There are other commercial processes available for the production of butylenes. However, these are site‐ or manufacturer‐specific. Any of these processes can become an important source in the future. Several technologies are emerging for the production of isobutylene to meet the expected demand for isobutylene: deep catalytic cracking; superflex catalytic cracking; dehydrogenation of butanes; and the Coastal process of thermal dehydrogenation of butanes. There are four types of separation methods available: selective removal of isobutylene by polymerization and separation of 1‐butene; use of addition reactions with alcohol, acids, or water to selectively produce pure isobutylene and 1‐butene; selective extraction of isobutylene with a liquid solvent, usually an acid; and physical separation of isobutylene from 1‐butene by absorbents. There are three important processes for the production of isobutylene; the extraction process using an acid to separate isobutylene; the dehydration oftert‐butyl alcohol, formed in the Oxirane process; and the cracking of MTBE. Handling requirements are similar to liquefied petroleum gas (LPG). Butylenes are not toxic. The effect of long‐term exposure is not known; hence, they should be handled with care. They are volatile and asphyxiants. Care should be taken to avoid spills because they are extremely flammable.
Butyl Rubber
Authors: Webb Robert N. , Shaffer Timothy D. , Tsou Addy H.
Published: July 2004

Butyl rubber and other isobutylene polymers in wide use include various homopolymers and copolymers. Low levels of unsaturation for subsequent cross‐linking are incorporated by copolymerization with isoprene. Halogenation at the unsaturation site provides additional cross‐linking mechanisms and covulcanization with highly unsaturated elastomers. Polymers containing star branches, conjugated‐diene sites, divinylbenzene, and brominated
p
‐methylstyrene have also been synthesized. Isobutylene polymers are polymerized by a cationic mechanism, using a Brønsted acid as an initiator and a Lewis acid as a coinitiator, eg, water and aluminum chloride. Molecular weights range from several hundred for terminally unsaturated polybutenes to over a million for elastomer grades.

The
T
g
of polyisobutylene is about −70°C, and the polymer is amorphous in the unstrained state. The polymers exhibit a broad damping peak and a low plateau modulus. They display an exceptionally low permeability to gases, and are widely used as air retention barriers in tires. Optimum physical properties are obtained by compounding with carbon black and other fillers. Various mechanisms are used to cross‐link the compounds into elastomeric vulcanizates. Sulfur is used to provide polysulfidic cross‐links, while resin and zinc oxide cure systems give carbon–carbon cross‐links. Besides inner tubes and innerliners, butyl rubbers are used in blends to improve cut‐growth resistance and wet‐skid resistance. Blends with thermoplastic resins improve toughness. Polyisobutylenes enjoy extensive use as adhesives and caulks, and are chemically modified for use in lubricants as dispersants.
Calcium Carbonate
Authors: Carr F. Patrick , Frederick David K.
Published: July 2004

Calcium carbonate, CaCO
3
, occurs naturally as the principal constituent of limestone, marble, and chalk. Powdered calcium carbonate is produced by two methods on the industrial scale. It is quarried and ground from naturally occurring deposits and in some cases beneficiated. It is also made by precipitation from dissolved calcium hydroxide and carbon dioxide. The natural ground calcium carbonate and the precipitated material compete industrially based primarily on particle size and the characteristics imparted to a product. Calcium carbonate is one of the most versatile mineral fillers and is consumed in a wide range of products, including paper, paint, plastics, rubber, textiles, caulks, sealants, and printing inks. High purity grades of both natural and precipitated calcium carbonate meet the requirements of the
Food Chemicals Codex
and the
United States Pharmacopeia
and are used in dentifrices, cosmetics, foods, and pharmaceuticals. Calcium carbonate occurs naturally in three crystal structures: calcite, aragonite, and, although rarely, vaterite. The commercial grades of calcium carbonate from natural sources are either calcite, aragonite, or sedimentary chalk. In most precipitated grades aragonite is the predominant crystal structure. Calcium carbonate is listed as a food additive and not considered a toxic material. The exposure to dust is regulated, and both natural ground and precipitated calcium carbonates can contain low levels of impurities that are regulated.
Fluorine Compounds, Inorganic, Calcium
Authors: Vrana Lisa M.
Published: July 2004

Calcium fluoride, commonly called fluorspar or fluorite, is the principal fluoride‐containing mineral. Whereas there are some domestic U.S. sources, much of the fluorspar used in the United States is imported. Fluorspar is marketed in several grades: metallurgical fluorspar sold as gravel, lump, or briquettes; ceramic‐grade fluorspar; and acid‐grade fluorspar. The latter is used in the open‐hearth process for the production of steel as well as to produce hydrogen fluoride.
Calcium Sulfate
Authors: Lancia Amedeo , Musmarra Dino , Prisciandaro Marina
Published: July 2004

Calcium sulfate, CaSO4, has several forms, ie, calcium sulfate dihydrate (commercially known as gypsum), calcium sulfate anhydrous (anhydrite), calcium sulfate hemihydrate, present in two different structures, α‐hemihydrate and β‐hemihydrate (commercial name of β‐form: stucco or plaster of Paris). It is found abundantly in many area of the world, where it is extracted by mining or quarrying and recently was obtained as a by‐product by numerous industrial applications. In natural deposits, the main form is the dihydrate, some hemihydrate is also present in most areas, although to a lesser extent. Gypsum is also obtained as a by‐product of various chemical processes. The main sources are from processes involving scrubbing gases evolved in burning fuels that contain sulfur (FGD gypsum), and the chemical synthesis of chemicals, such as sulfuric acid, phosphoric acid, titanium dioxide, citric acid, and organic polymers. The hemihydrate is normally produced by heat conversion of the dihydrate. Stucco is the primary constituent used to fabricate products and in formulated plasters used in job or shop‐site applications. About 20–25 million metric tons of calcium sulfate are consumed annually. About 20% of it, in the dihydrate form, is used in fabricated or formulated building materials, Portland cement set regulation, and agricultural soil conditioning, while ∼80% is processed into the commercially usable hemihydrate. The dehydration of gypsum, commonly referred to as calcination in the gypsum industry, is used to prepare hemihydrate, or anhydrite. In addition, calcium sulfate precipitation is relevant in scaling problems, where gypsum formation is an unwanted occurrence, such as in water desalination, industrial water recovery in cooling tower technology, water distillation, and phosphoric acid production.
Sugar, Cane Sugar
Authors: Clarke Margaret A.
Published: July 2004

This article outlines the history of sugarcane as a source of sucrose sweetener, and traces the development of major industrial unit processes for sugar production. Chemical and physical properties of sucrose, specifically of cane sugar, are listed. Cultivation and harvest of sugarcane and product of either raw cane sugar or direct consumption (plantation white) cane sugar are described. Production of noncentrifugal cane sugar is described briefly. Yields and production statistics for recent years are given, and production figures are listed throughout. Processes for refining raw sugar into refined white and brown products are delineated, and the products and their standards are described. Other products from cane sugar and sugarcane are described.
Carbon Black
Authors: Wang Meng‐Jiao , Gray Charles A. , Reznek Steve A. , Mahmud Khaled , Kutsovsky Yakov
Published: July 2004

Carbon black is a generic term for an important family of products used widely to modify the mechanical, electrical, and other physical properties of the medium in which it is dispersed. It is the most widely used nanomaterial, with particle dimensions ranging from tens to a few hundred nanometers (nms). It plays a major role in elastomers, plastics, paints and inks as a reinforcing agent, a black pigment, and an electrically conductive material. This article provides a comprehensive review of the technical and commercial aspects of carbon black usage. The history of carbon black, its microstructure, chemical composition, morphology, surface activity, and characterization are discussed. The mechanism of carbon black formation and its manufacture, including oil‐furnace black process, thermal black process, acetylene black process, lampblack process, and impingement black process, is described. A separate section is included on newly developed surface modification technologies and related commercial applications. One section is devoted to the properties, applications and markets of the two main types of carbon blacks, rubber grades and special grades. The rubber grades are primarily used as a reinforcing agent in tire and other rubber products to improve their mechanical properties. Most of the special grades are manufactured to meet specific product specifications for imparting certain properties required by the end use products, such as dispersion, pigmentation and electrical conductivity. The health, safety, and environmental section includes a summary of recent health studies.
Carbonated Beverages
Authors: Morrow R. Steve , Quinn Christine M.
Published: July 2004

Carbonated beverages were first introduced in the late 1880s. The annual per capita consumption of soft drinks in the United States has steadily risen from 16 oz (

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) in 1860 to nearly 48 gallons (

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) today.

The ingredients used to produce soft drinks include water, nutritive or nonnutritive sweeteners, acidulants, preservatives, carbon dioxide, colorants, and flavoring ingredients. Manufacturing of soft drinks generally includes preparing syrup from ingredients and then mixing with carbon dioxide and water. Quality control programs for ingredients, syrups, beverages, and packaging materials are conducted to ensure the integrity of the beverage.

Beverages are packaged in steel or aluminum cans, returnable and nonreturnable glass, and plastic bottles. Recycling and source reduction are important issues to the soft drink industry. New packaging utilizing recycled materials, market growth, and development of new nonnutritive sweeteners are important areas for future development.
Carbon and Graphite Fibers
Authors: Venner Joseph G.
Published: July 2004

Carbon and graphite fibers have rapidly emerged as a primary reinforcement in composite applications requiring high specific stiffness and strength. These fibers are manufactured from the thermal conversion of polyacrylonitrile, pitch, or rayon precursors. The modulus and strength of carbon fibers can be adjusted through control of process conditions resulting in a family of carbon fiber products classified as low modulus (LM), standard, intermediate modulus (IM), high modulus (HM), and ultrahigh modulus (UHM) carbon fiber. Primary process steps including precursor formation, stabilization, carbonization, surface treatment, and sizing are described. Basic interrelationships between fiber structure, fiber properties, and process conditions are reviewed. Brief overviews of quality control approaches, safety and health considerations for handling carbon fiber, applications, and market growth are also included.
Metal Carbonyls
Authors: McIndoe J. Scott , Dyson Paul J.
Published: July 2004

Carbon monoxide forms a host of metal carbonyl complexes, at least one for every transition metal. Mononuclear, polynuclear, and heteronuclear metal carbonyls are all known. The complexes, of general formula Mx(CO)y, may be charged or neutral; the metal or metals are in low, zero, or negative oxidation states. Synthesis of the metal carbonyls usually proceeds either from the reduction of the corresponding metal salt, although direct reaction between the metal and CO takes place for certain elements. Clusters are usually made via condensation of lower molecular weight compounds. The structure and bonding of the metal carbonyls, including those of cluster compounds, follow well‐defined rules. Metal carbonyls are extremely useful as reagents in organic synthesis and catalysts, playing a pivotal role in both the Reppe and the oxo processes, as well as in the preparation of fine chemicals.
Copper Alloys, Cast Copper Alloys
Authors: Twarog Daniel L.
Published: July 2004

Cast copper alloys are used for their generally superior corrosion resistance, high electrical and thermal conductivities, and good bearing and wear qualities. These alloys are identified by Unified Numbering System designation. Irregular and complex external and internal shapes can be produced by various casting methods at less overall cost than by other means. The commonly used casting methods are compared, and casting characteristics of both single and polyphase alloys are described.

Cast copper alloys include both yellow and red brasses as well as semired brasses and many bronzes. Alloy composition, on which the alloy properties depend, and usage are given.
Initiators, Cationic
Authors: Faust Rudolf
Published: July 2004

Cationic initiation in general and the cation donor (initiator)/Friedel‐Crafts acid (coinitiator) initiating system in particular are reviewed. The efficiency of a particular initiating system depends on the reactivity of the initiating cation relative to that of the propagating center. The strength of the Friedel‐Crafts acid and the nucleophilicity of the formed counteranion also affect the rates of initiation and propagation as well as the influence of solvent polarity. Controlled initiation in the absence of chain transfer, the inifer technique, and living cationic polymerization systems are reviewed. These systems have resulted in head group control, molecular weight, and end group control, and in the synthesis of well‐defined materials with controlled architecture, molecular weight, molecular weight distributions, and end functionalities.
Cell Culture Technology
Authors: Karkare Subhash B.
Published: July 2004

Cell culture technology refers to the
in vitro
processes employed for the growth of mammalian, insect, or plant cells to manufacture biochemicals of commercial importance. Cell culture products, typically therapeutics or medical diagnostics, are regulated by the FDA. The market for cell culture‐derived products is growing and is expected to continue to grow into the twenty‐first century.The technology involved in cell growth is often dependent on cell line type. Hybridoma cells, used for the production of monoclonal antibodies, can be grown in suspension cultures in a manner similar to that used in microbial fermentation. Other cell systems require microcarriers or supports. All of these cells have higher shear sensitivity than microbial cells. Both batch and continuous processes, cell growth kinetics, cell aeration, growth media, product isolation, and purification are discussed, as are safety regulations and standards.
Fibers, Cellulose Esters
Authors: Serad George A.
Published: July 2004

The principal cellulose ester fiber is cellulose acetate, a partially acetylated cellulose, also called acetate or secondary acetate. Although widely used in textiles, its primary use is now for the preparation of cigarette filters, which consumed 65% of the 731,000 metric tons produced worldwide in 1991. Cellulose triacetate is an almost totally acetylated cellulose, but environmental considerations encountered in the preparation of fibers have almost totally eliminated its production.

This article initially describes the physical and chemical properties of cellulose acetate and triacetate polymers and fibers. A review of the manufacturing process operations and considerations follows, providing an overview of the key process steps. Since both textile and cigarette filter applications are commercially important, both are described to illustrate the products available and how they are used. Finally, a brief overview of some smaller volume applications provides some insight into other possible uses.
Cement
Authors: Kosmatka Steven
Published: July 2004

Inorganic hydraulic cements, upon reaction with water, form relatively insoluble, bonded aggregations having considerable strength and dimensional stability. The cement produced in the greatest volume is portland cement, which is most often used in concrete for construction. Portland cements contain calcium and silicon oxides together with additives such as alumina, ferrites, and gypsum. Cement clinker chemistry and the portland cement phases that form, including composition and reaction rates, are discussed. Cement hydration and structure are described as are properties such as strength and porosity of concretes. Chemical admixtures for concrete are also reviewed. Either a dry or a wet process may be used in cement manufacture; both are described. The uses of portland cements, special purpose and blended cements, and calcium aluminate cements are reviewed.
Ceramics As Electrical Materials
Authors: Buchanan Relva C. , Roseman Rodney D.
Published: July 2004

Ceramic materials contribute important component functions, including resistance, capacitance, magnetic inductance, and environmental sensing to a variety of microelectronics applications. The material choice may be based on dominant magnetic, ferroelectric, piezoelectric, pyroelectric, electrooptic, electrochemical, mechanical, or thermal properties, but the underlying function of primary importance is the electrical conductivity, which determines overall insulation behavior and device utility. Since the components are typically shaped by ceramic processes, understanding of their properties require detailed knowledge of the composition, crystal structure, microstructure, and processing conditions. The role of defects and substitution (stoichiometry) is important also in controlling electrical conduction, especially for materials containing one or more cations of variable valence. Defects likewise play a major role in the performance of ceramic sensor devices, which serve as the detecting or switching element in many circuit operations. The sensing operation is typically based on a sharp change in electrical conduction, which reflects a significant change in the thermal, chemical, mechanical, optical, electrical, or magnetic environment of the device. In this article, the basic definitions of electrical terms relating to conduction, dielectric, magnetic, and sensor properties are presented, but the primary focus is on the influence of the materials characteristics on the electrical properties detailed above, with emphasis on the electrical conductivity mechanisms for the different categories of materials.
Composite Materials, Ceramic‐Matrix
Authors: Butler E. P. , Fuller E. R.
Published: July 2004

Ceramic‐matrix composites are materials for use in high temperature structural applications. The intrinsic properties of the ceramic‐matrix such as high melting point, high chemical stability, high elastic modulus and hardness, high wear and creep resistance along with low mass density relative to metallic materials are coupled with the properties of high fracture resistance and flaw insensitivity when reinforced with a high strength second phase. The varieties of reinforcements include particles, platelets, whiskers, and continuous fibers. Placement of reinforcements within the matrix determines the isotropy of the composite properties. Particulate reinforced matrices derive their toughness from processes such as crack deflection, crack pinning and bowing, microcracking, and frictional bridging mechanisms. Whisker, platelet, and fiber‐reinforced matrices derive their toughness from crack‐wake frictional bridging and pull‐out mechanisms. For the mechanism of crack‐wake bridging the most important aspect of the composite is the interface between the reinforcement and the matrix. It must be weak enough to allow debonding around the reinforcement leaving it as an intact bridging element in the crack‐wake. Control of the interface between the matrix and reinforcements is extremely important in optimization of composite properties.
Bakery Processes, Chemical Leavening Agents
Authors: Chung Frank H. Y.
Published: July 2004

Chemical leavening involves the action of an acid on bicarbonate to release carbon dioxide gas for aeration of a dough or batter during mixing and baking. The aeration provides a light, porous cell structure, fine grain, and a texture with desirable appearance along with palatability to baked goods. There are essentially two components in a chemical leavening system: bicarbonate that supplies carbon dioxide gas and an acid which triggers the liberation of carbon dioxide from bicarbonate upon contact with moisture. Sodium bicarbonate (baking soda) is the primary source of carbon dioxide gas in practically all chemical leavening systems. The prevalent baking acids in modern chemical leavening systems are sodium or calcium salts of ortho, pyro, and complex phosphoric acids. Baking soda determines the amount of carbon dioxide evolved, whereas the type of acid controls the speed of liberation. By far, the greatest use of leavening in the home is in preleavened mixes. Pancake mixes, biscuit mixes, and cake mixes have long been established as commercial products. Sales of frozen or refrigerated doughs and batters have increased rapidly in recent years. This trend is attributable to increased refrigeration and freezer capacity in stores and to the development of new and improved ingredients. Practically all of the leavening acids used in the mix industry today are of the phosphate type. The blending of baking powder is essentially a physical mixing of the various components in a large‐scale batch mixer and is often carried out in automated plants.
Chemurgy
Authors: Clark J. Peter
Published: July 2004

Chemurgy is the branch of applied chemistry concerned with the industrial use of biomass for fuel and chemicals. The biomass may be industrial crops, such as trees, cotton, or oilseeds; food crops, such as corn or soy; or wastes and by‐products, such as forest trimmings, tall oil, or straw. Chemurgic processes and applications range from relatively simple physical or chemical separations, such as milling, to more sophisticated enzymatic hydrolysis of cellulose and fermentation to produce ethanol. Lignocellulosic materials, such as forest or farm wastes, can, in principle, generate most of the basic chemical building blocks now produced from oil and gas. Pyrolysis can generate oils and fuel gases to serve as alternative energy sources. The viability of chemurgic processes depends heavily on the costs of fossil fuels, considered as economic alternatives, and on the costs of biomass raw materials and the efficiencies of conversion processes.