bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fluid Catalytic Cracking (FCC) Units, Regeneration
Authors: Upson L. L. , Rosser F. S. , Hemler C. L. , Palmas P. , Bell L. E. , Reagan W. J. , Hedrick B. W. 
Published: July 2004

AbstractThe fluid catalytic cracking (FCC) process is an important refinery process in the United States. Catalyst regeneration is an essential part of this process. In the reactor section of a FCC unit, hydrocarbon feed is combined with hot fluidizable cracking catalyst at the base of the riser reactor. Catalyst and hydrocarbon vapors pass up the riser in a dilute‐phase, plug‐type flow and discharge into the reactor vessel where catalyst and hydrocarbon vapors are separated. When in contact with the catalyst, the hydrocarbon feed cracks to form gasoline, middle distillates, liquefied petroleum gas (LPG), and fuel gas. Coke, which is also formed, deposits on the catalyst surface and greatly reduces the catalyst activity. To restore its activity, the catalyst passes into the regenerator section where the coke is burned off. The heat released from coke burning is completely used to provide the heat requirements on the reactor side. Heat balance, environmental concerns, regenerator configuration and design, and other parameters of FCC are discussed.
Fluoroethers and Fluoroamines
Authors: Flynn Richard M. 
Published: July 2004

Abstract

Perfluoroaliphatic ethers and tertiary amines are members of a class of unreactive compounds known in the industry as inert fluids. These compounds are prepared by electrochemical fluorination, direct fluorination using elemental fluorine, or cobalt trifluoride fluorination. They are nontoxic, nonflammable, have densities of 1.7–1.9 g/cm
3
, surface tensions of 9–19 mN/m, and lower kinematic viscosities than hydrocarbons. Their thermal stabilities are comparable to the perfluoroalkanes. The low polarizability of these liquids makes them excellent insulators. Their chemical properties are characterized by their extreme unreactivity. Perfluoroaliphatic ethers and amines do not react with most oxidizing or reducing agents nor with strong acids or bases. They are generally poor solvents for most organic compounds, with the exception of highly fluorinated compounds. The lower molecular weight compounds are used in the electronics industry as heat‐transfer fluids, for testing of electronic circuitry, and in vapor‐phase soldering. The higher molecular weight polymers are used as hazardous duty vacuum pump oils, specialty greases, and lubricants.
Fluorinated Higher Carboxylic Acids
Authors: Savu Patricia M. 
Published: July 2004

AbstractPerfluorinated carboxylic acids are corrosive liquids or solids. The acids are completely ionized in water. The acids are of commercial significance because of their unusual acid strength, chemical stability, high surface activity, and salt solubility characteristics. The higher members of the series have the property of decreasing the surface tension of aqueous solutions well below the point possible with any type of hydrocarbon surfactant. There are five methods for the preparation of long‐chain perfluorinated carboxylic acids and derivatives: electrochemical fluorination, direct fluorination, telomerization of tetrafluoroethylene, oligomerization of hexafluoropropylene oxide, and photooxidation of tetrafluoroethylene and hexafluoropropylene. In general, the reactions of the perfluoroacids are similar to those of the hydrocarbon acids, although in some cases the electronegativity of the perfluoroalkyl groups make formation of certain derivatives easier or harder. A general summary of formation and properties of the derivatives of perfluorinated acids is discussed. Data on the fluorinated dicarboxylic acids and their derivatives are also summarized.
Fluorine Compounds, Inorganic, Fluorosulfuric Acid
Authors: Evans Francis E. , Mani Ganpat 
Published: July 2004

AbstractThe two most commercially important sulfur‐containing inorganic fluorine compounds are fluorosulfuric acid and sulfur hexafluoride. Fluorosulfuric acid is used as a fluorinating reagent in the preparation of such compounds as boron trifluoride and silicon tetrafluoride, and as a catalyst in organic reactions for alkylation, acylation, polymerization, sulfonation, and isomerization. Fluorosulfuric acid is itself a strong acid. When combined with certain inorganic fluorides, the system exhibits superacid properties. Properties, manufacture, and uses are discussed.Of the known sulfur fluorides, sulfur hexafluoride and sulfur tetrafluoride are available commercially. Sulfur hexafluoride, nonflammable and of high chemical stability, has a high dielectric, and is used widely in electrical and electronic equipment such as circuit breakers, capacitors, microwave components, etc. Sulfur tetrafluoride is used as a fluorinating reagent. Properties, manufacture, and uses are described. Other sulfur fluorides are discussed.
Foamed Plastics
Authors: Suh Kyung W. 
Published: July 2004

AbstractThis article is concerned with the general theory of expansion, manufacturing processes, properties, and applications of foamed (cellular) plastics. The high strength‐to‐weight ratio, excellent insulating properties, and cushioning properties of cellular plastics have contributed to the development and growth of the broad range of cellular plastics in use. The total usage of foamed plastics in the United States has risen from 441 thousand metric tons in 1967 to 1.6 million metric tons in 1982 and has been projected to rise to about 2.8 million metric tons in 1995.The manufacturing processes for cellular polymers are described in terms of three classified methods based on the cell growth and stabilization processes. The properties of cellular plastics including mechanical, thermal, electrical, and environmental aging properties, are summarized. A general discussion is given on the properties of cellular plastic necessary in many applications such as the comfort cushioning, thermal insulation, packaging, structural components, buoyancy, electrical insulation, and space‐filling markets. A brief discussion is also given on the process economics, raw materials, and energy considerations for the commercial products of primary importance.
Folic Acid
Authors: Rawalpally Thimma R. 
Published: July 2004

AbstractL‐Folic acid is a water‐soluble B‐complex vitamin. Folates are a group of compounds which are structurally derived from pteroylglutamic acid or folic acid. Folic acid is a precursor of several important enzyme cofactors required for the synthesis of nucleic acids and in the metabolism of certain amino acids. Folic acid is synthesized only by plants and microorganisms. The neural tube defect may be caused by a deficiency of folic acid. All known commercial syntheses are based on the three component method process developed in the late 1940s. Industrial production of folic acid by genetically engineered microorganisms or extraction from natural sources is not yet economically viable. A brief review of the biosynthesis and the physiological role of folic acid is presented.
Food Processing
Authors: Farkas Daniel F. 
Published: July 2004

AbstractFood processing includes unit operations and processes for converting plant and animal tissue to edible foods and ingredients. These processes, which can be grouped by raw product preparation, assembly to consumer products, and preservation processes are regulated by federal laws. Food preservation techniques vary according to food and length of storage.Foods are preserved before or after packaging using combinations of heat, chemical additives and fermentation products, refrigeration or freezing, dehydration, or mechanical methods such as filtration and ultrahigh pressure. Foods sterilized before packaging must be packaged aseptically. Heat sterilization of foods in rigid and flexible packages is also possible. Preservation techniques and the specialized equipment used are described. Process control and optimization are discussed.
Foods, Nonconventional
Authors: Litchfield John H. 
Published: July 2004

AbstractNonconventional foods can be produced from chemicals such as carbohydrates, hydrocarbons, and industrial organic chemicals by processes such as microbiological, enzymatic, or chemical synthesis; or from existing natural products containing carbohydrates, proteins, and fats by physical, chemical, microbiological, or enzymatic modification.Examples of nonconventional foods include single‐cell proteins, eg, dried cells of microorganisms such as algae bacteria, actinomycetes, yeasts, molds, and higher fungi; derived plant and animal products, eg, leaf meals and leaf protein concentrates, and fish and meat protein concentrates and isolates; synthetic products, eg, carbohydrates, fats, proteins, peptides, amino acids, and vitamins prepared by chemical, microbiological, or enzymatic synthesis; and manufactured or combination foods, eg, engineered, restructured, or textured foods.Nonconventional foods must have nutritional value to humans or animals, and functional value in foods which ensure quality and social and cultural acceptability. They also must meet regulatory agency requirements for safety for human consumption, including freedom from toxic, mutagenic, and carcinogenic substances and pathogenic microorganisms.
Formic Acid
Authors: Drury David J. 
Published: July 2004

AbstractFormic acid is the simplest of the homologous series of alkyl carboxylic acids. It is a liquid boiling at 101C with an intense pungent smell. It forms hydrogen‐bonded dimers in the gas phase and polymeric chains in the solid state.Many of the chemical properties of formic acid are broadly similar to those of other aliphatic carboxylic acids, but with the differences commonly found in the first member of a homologous series. It is, for example, a stronger acid than any of the higher homologues. Formic acid can decompose either to CO and H2O or CO2] and H2.Formic acid is manufactured industrially as a medium‐tonnage commodity (world capacity ca 330,000 t/yr). It is produced by three different processes: from formate salts, by liquid‐phase oxidation of hydrocarbons, and by carbonylation of methanol to give methyl formate, followed by hydrolysis. The last of these is the most important industrially.Formic acid is shipped in concentrations of 85‐;mt 99%. Appropriate precautions must be followed in shipping and handling of this corrosive material.In Europe formic acid's largest use is as a silage addition whereas in the United States this application scarcely exists, and formic acid's main U.S. markets are in the textile and rubber industries and as a chemical intermediate.
Formaldehyde
Authors: Gerberich H. Robert , Seaman George C. 
Published: July 2004

AbstractFormaldehyde is a versatile, reactive substance, basic to the chemical industry because of its low cost and ease of production. It is manufactured by vapor‐phase oxidation of methanol using two principal processes. One method employs a pure silver catalyst and the other an iron molybdate catalyst. Several other processes are under development, but none have been commercialized. All processes are capital intensive, requiring integrated reaction, heat recovery, and purification systems to achieve optimum economic benefits.Formaldehyde is sold as concentrated, aqueous solutions, and may contain methanol to inhibit polymerization. It is also sold in alcohol solutions, which contain little water. Its principal uses are in the production of amino and phenolic resins, polyhydric alcohols, acetal resins, paraformaldehyde, and fertilizers. It reacts with numerous organic compounds in condensation‐type reactions, resulting in formation of one or more new carbon‐carbon bonds.In recent years, formaldehyde has come under increased scrutiny because of its potential negative health effects. It is an irritant to the eyes, nose, and throat, and is a suspected human carcinogen.
Friedel‐Crafts Reactions
Authors: Olah George A. , Reddy V. Prakash , Prakash G. K. Surya 
Published: July 2004

AbstractAfter the initial discovery by Friedel and his American associate, James Mason Crafts, that anhydrous aluminum chloride could be used as a condensing agent in a general synthetic method for furnishing an infinite number of hydrocarbons. They extended their discoveries of the catalytic effect of aluminum chloride in a variety of organic reactions:(1)reactions of alkyl and acyl halides and unsaturated compounds with aromatic and aliphatic hydrocarbons;(2)reactions of acid anhydrides with aromatic hydrocarbons;(3)reactions of oxygen, sulfur, sulfur dioxide, carbon dioxide, and phosgene with aromatic hydrocarbons;(4)cracking of aliphatic and aromatic hydrocarbons; and(5)polymerization of unsaturated hydrocarbons. The diversity of reactions is astounding.Many important industrial processes such as the production of high octane gasoline, ethylbenzene (eventually leading to polystyrene), synthetic rubber, plastics, and detergent alkylates are based on Friedel‐Crafts chemistry. Friedel‐Crafts‐type reactions are generally considered to be any substitution, isomerization, elimination, cracking, polymerization, or addition reaction that takes place under the catalytic effect of Lewis acid‐type acidic halides (with or without cocatalysts) or Brønsted acids. Friedel‐Crafts reactions can be divided into two general categories: alkylations and acylations. Within these two broad areas there is considerable diversity. Friedel‐Crafts catalysts are electron acceptors, ie, Lewis acids. Catalysts include acid halides (Lewis acids), metal alkyls and alkoxides, protic acids (Brønsted Acids), acidic oxides and sulfides (acidic chalcogenides), acidic cation‐exchange resins, and superacids (Brønsted superacids, super Lewis acids, Brønsted‐Lewis superacids, solid superacids, and superacidic zeolites).
Fungicides, Agricultural
Authors: Dreikorn Barry A. , Owen W. John 
Published: July 2004

AbstractPathogenic fungi cause a substantial reduction in expected crop yields; further losses can result during storage of harvested crops. For those fungi that can seriously affect economically important plants, means have been sought to control these infections by crop rotation and husbandry, genetic manipulation of the plant species, and external treatment of plants using agricultural fungicides.Agricultural fungicide application accounts for about 20% of all pesticide use. Agricultural fungicides can be applied to the soil to control fungi that are resident there, to the seed or foliage of the plant to be protected, or to harvested produce to prevent storage losses. Those applied to the soil are in many instances nonselective, volatile soil sterilants, such as formaldehyde, which kill all soil organisms, including fungi. Seed and foliar‐applied agricultural fungicides, are discussed also. Fungicides are classified herein as being nonsystemic or systemic. The nonsystemic fungicides have a protectant mode of action and must be applied to the surface of a plant generally before infection takes place. These do not translocate from the site of application. The systemic fungicides can penetrate the seed or plant and are then redistributed within to unsprayed parts or subsequent new growth, rendering protection from fungal attack or eradicating a fungus already present. Well over 100 plant pathogens have become resistant to various fungicides under field conditions. Failure of the acyl alanines, benzimidazoles, thiophanates, carboxanilides, dicarboximides, hydroxypyrimidines, some organophosphates, and most of the antibiotics has occurred. In other cases, a moderate decrease in sensitivity without a rapid loss of disease control has been observed as in the case of sterol biosynthesis inhibitors and organophosphates. The most effective approach is to use fungicides having different modes of action in combination, either as mixtures or in alternation, possibly utilizing both specific site and multisite inhibitors. Because of resistance problems great importance is attached to chemistries that inhibit novel fungal enzyme targets.Newer fungicides, in order to retain cost‐effectiveness, need to be very highly active, which also serves to achieve efficacy in the field at low dose rates thus keeping environmental pollution problems as small as possible. Recombinant DNA technologies are expected to play an escalating role in the validation of such biorational targets.
Furnaces, Fuel‐Fired
Authors: Bozzuto Carl R. 
Published: July 2004

AbstractA furnace is a device (enclosure) for generating controlled heat with the objective of performing work. In fossil‐fuel furnaces, the work application may be direct (eg, rotary kilns) or indirect (eg, plants for electric power generation). The furnace chamber is either cooled (waterwall enclosure) or not cooled (refractory lining). Furnaces related to metallurgy such as blast furnaces are excluded. Fuel‐fired furnaces primarily utilize carbonaceous or hydrocarbon fuels. Since the purpose of a furnace is to generate heat for some useful application, flame temperature and heat transfer are important aspects of furnace design. Industrial furnaces are an order of magnitude smaller than power‐plant furnaces since the applications are usually on an individual basis rather than feeding power to a regional electric grid. Like the power‐plant furnace, the function of the industrial furnace usually is to generate steam, generally for a chemical process, mechanical power, or heating application, rather than electric power generation. New furnace concepts in evolutionary stages include fluidized‐bed furnaces, coal gasification furnaces, and MHD furnaces. Fluidized‐bed combustion has reached commercial‐scale operations.
Helium Group Gases
Authors: Hwang Shuen‐cheng , Weltmer William R. 
Published: July 2004

AbstractThe helium‐group gases are characterized by completely filled valence electron shells. Helium, argon, and neon are commercially available, but krypton, xenon, and radon are quite rare. Principal uses of commercial helium include those as a lifting gas, as an inert carrier gas, and as a cryogenic refrigerant. Helium‐3 and helium‐4, which are both stable isotopes used in cryogenics, differ significantly in their liquid properties because of quantum mechanical effects. Argon finds use principally as an inert gas in industries ranging from electronic ones to steelmaking. Neon is employed as a filling gas in detection chambers and in light sources from commercial signs to lasers.Sources and properties of these gases are discussed. Production of helium from natural gas, and of argon and neon from air separation plants, is presented.
Fuels, Synthetic, Gaseous Fuels
Authors: Speight James G. 
Published: July 2004

AbstractFUELS, SYNTHETIC, GASEOUS FUELS.Whereas coal continues to be a principal source of substitute natural gas, a more recently recognized source is petroleum. Coal can be converted to gas by several routes, but often a particular process is a combination of options chosen on the basis of the product desired, ie, low, medium, or high heat‐value gas. Coal gas is the term applied to the mixture of gaseous constituents that are produced during the thermal decomposition of coal at temperatures in excess of 500°C, often in the absence of oxygen (air). A solid residue (coke, char), tars, and other liquids are also produced in the process.Next to combustion, carbonization represents one of the largest uses of coal. Carbonization is essentially a process for the reproduction of a carbonaceous residue by thermal decomposition, accompanied by simultaneous removal of distillate, of organic substances. This process may also be referred to as destructive distillation. The gasification of coal is essentially the conversion of coal by any one of a variety of processes to produce combustible gases.
Gasoline and Other Motor Fuels
Authors: Hochhauser Albert M. 
Published: July 2004

AbstractGasoline and Other Motor Fuels. Albert M. Hochhauser (Exxon Research and Engineering Co.). Gasoline and other motor fuels comprise the largest single use of energy in the U.S. The cost of this energy continues to be a primary factor in the national economy. The fraction of resources from which these fuels come that is provided by foreign sources is a matter of political concern. Rapid increases in the price of crude oil has led to programs for developing alternative sources of fuels such as coal, oil shale, and natural gas. Alternative fuels are more important for the potential to reduce emissions and improve air quality than for energy self‐sufficiency.All motor fuels in the U.S. are manufactured by private companies. Many participate in other aspects such as refining or marketing. Gasoline demand is determined by the numbers of cars, paved roads, population, and economic growth. Predictions for future demand are somewhat divided. Gasoline must meet exacting specifications and vary according to location, temperature and altitudes at which the product is used. Octane is probably the single most recognized measure of gasoline quality. Petroleum refining begins with distillation of crude oil into many fractions. Most gasoline in the U.S. is obtained by catalytic cracking. Reforming increases octane. Gasoline additives (e.g., dyes, antioxidants, detergents, etc.) are used to improve performance. Stricter emission standards have resulted in changes in vehicle hardware. Diesel fuel, second to gasoline, is used in a wide variety of engines. The ability of diesel fuel to burn properly is described by its cetene number. Diesel manufacturers have found it difficult to meet emission standards Alternative fuels include those made from coal and shale, methanol, compressed natural gas and liquefied petroleum gas. Use of alternative fuels has been promoted for two reasons: potential emissions benefits and reduced dependence on imported petroleum.
Gastrointestinal Agents
Authors: Jacoby Henry I. 
Published: July 2004

AbstractThe primary aim in antiulcer therapy is either prevention of acid secretion from the gastric parietal cells or neutralization of the acid before it comes into contact with the ulcerated areas of the gastrointestinal tract. Long established therapy of duodenal ulcers, included diet, antacids, and anticholinergics. Of these, only antacids have been shown conclusively to be effective. The antacids can produce healing, but only when given in large and frequent doses. Antacids include aluminum hydroxide gel, precipitated calcium carbonate, magnesia and alumina suspension, magnesium oxide, magnesium trisilicate, magaldrate, and sodium bicarbonate.The therapy for duodenal ulcers changed drastically upon the introduction of cimetidine (an H2blocker) in the United States in 1977. Omeprazole is a potent antisecretory agent and is used only for acute therapy of ulcerative disease and esophagitis.Drugs acting by mechanisms not related to inhibition of gastric acid secretion have been introduced into therapy in the United States. Sucralfate, misoprostil Therapy also has been changed by the acceptance thatHelicobacter pylori, an organism able to withstand the acid media of the stomach, is associated with gastritis and ulcerative disease.Laxatives facilitate the passage and elimination of feces. Laxatives have traditionally been classified as bulking agents; contact, ie, stimulant; saline, ie, osmotic; and emollients, ie, lubricant.Commonly used antidiarrheals work by one of two mechanisms: effects on net intestinal secretion, or a decrease in intestinal propulsive motility.Antiemeticsmay act at a variety of physiological locations, eg, blockade of dopamine and effects at the chemoreceptor trigger zone, vestibular apparatus, or serotonin (5‐HT3) receptors. Gastric prokinetics are a new class of agent that can augment gastric emptying.