bluuebunny/crossref_metadata_2025_split huggingface dataset:
Adsorption, Gas Separation
Authors: Yon Carmen M. , Sherman John D. 
Published: July 2004

AbstractGas‐phase adsorption is widely employed for the large‐scale purification or bulk separation of air, natural gas, chemicals, and petrochemicals. An adsorbent attracts molecules from the gas, and the molecules become concentrated on the surface of the adsorbent and are removed from the gas phase. Most commercial adsorbents for gas‐phase applications are employed in the form of pellets, beads, or other granular shapes, most commonly packed into fixed beds through which the gaseous feed mixtures are passed. The growth in both variety and scale of gas‐phase adsorption separation processes, particularly since 1970, is due in part to continuing discoveries of new porous, high surface‐area adsorbent materials (particularly molecular sieve zeolites) and to improvements in the design and modification of adsorbents. To permit the recovery of pure products and to extend the adsorbent's useful life, adsorbents should generally be inert and not react with or catalyze reactions of adsorbate molecules. Commercially useful adsorbents can be classified by the nature of their structure (amorphous or crystalline), by the sizes of their pores, by the nature of their surfaces (polar, nonpolar, or intermediate), or by their chemical composition, of which the size of the pores is the most important initial consideration. Adsorption processes are temperature‐swing adsorption (TSA) and pressure‐swing (PSA) as well as purge‐swing cycles and nonregenerative approaches. Most adsorption processes use fixed beds, but some use moving‐ or fluidized‐beds or wheels.
Aerosols
Authors: Sciarra John J. , Sciarra Christopher J. 
Published: July 2004

Abstract
The aerosol container has enjoyed commercial success in a wide variety of product categories. Insecticide aerosols were introduced in the late 1940s, and shave foams, hair sprays, deodorants, paints, perfumes, whipped cream, and automotive products followed in the 1950s. Medicinal metered‐dose aerosol products have also been developed for use in the treatment of asthma, migraine headaches, and angina. Aerosol products are hermetically sealed, ensuring that the contents cannot leak, spill, or be contaminated. The packages can be considered to be tamper‐proof. They deliver the product in an efficient manner, generating little waste, often to sites of difficult access. By control of particle size, spray pattern, and volume delivered per second, the product can be applied directly without contact by the user. All aerosols consist of product concentrate, propellant, container, and valve (including an actuator and dip tube). The propellant, said to be the heart of an aerosol system, maintains a suitable pressure within the container and expels the product once the valve is opened. Propellants may be either a liquefied halocarbon, hydrocarbon, or halocarbon–hydrocarbon blend, or a compressed gas such as carbon dioxide, nitrogen, or nitrous oxide. Worldwide, use of CFC propellants, designated as Propellants 11, 12, and 114, is strictly limited to specialized medicinal aerosol products such as metered‐dose inhalers. The most popular aerosol containers are the three‐piece, tin‐plated steel container and the aluminum container. All aerosols are produced by either a cold‐filling or pressure‐filling process. Barrier packs utilize a plastic bag or piston to separate the product from the propellant.
Alcohols, Polyhydric
Authors: Hunter William N. 
Published: July 2004

AbstractPolyhydric alcohols or polyols contain three or more CH2OH functional groups. The monomeric compounds have the general formula R(CH2OH)n, whereand R is an alkyl group or C.CH2OH; the dimers and trimers are also commercially significant. Each polyhydric alcohol is a white solid, ranging from the crystalline pentaerythritols to the waxy trimethylol alkyls. The trihydric alcohols are very soluble in water, as is ditrimethylolpropane. Pentaerythritol is moderately soluble and dipentaerythritol and tripentaerythritol are less soluble. Pentaerythritol and trimethylolpropane have no known toxic or irritating effects. Finely powdered pentaerythritol, however, may form explosive dust clouds. Pentaerythritol is produced by reaction of formaldehyde and acetaldehyde in the presence of a basic catalyst, generally an alkali or alkaline‐earth hydroxide. Dipentaerythritol and tripentaerythritol are obtained as by‐products of the pentaerythritol process and may be further purified by fractional crystallization or extraction. Pentaerythritol and trimethylolpropane are classified as nuisance particulate and dust, respectively. The most important industrial use of pentaerythritol is in a wide variety of paints, coatings, and varnishes, where the cross‐linking capability of the four hydroxy groups is critical.
Alcohol Fuels
Authors: Jackson Michael D. , Moyer Carl B. 
Published: July 2004

AbstractA wide variety of countries have, at various times, explored the use of either methanol or ethanol alcohol fuels as alternatives to diesel and gasoline fuels. Recently the United States has demonstrated light and heavy‐duty vehicles using alcohols but has not yet passed beyond the use of limited amounts of alcohols as gasoline components. The potential benefits of alcohol fuels include increased energy diversification accompanied by some energy security and balance of payments benefits, and air quality improvements. The Clean Air Act of 1990, emission standards set out by the State of California, and the 1992 Comprehensive National Energy Policy Act may serve to encourage the substantial use of alcohol fuels, unless gasoline and diesel technologies offer comparable advantages. Both methanol and ethanol have high octane values and allow high compression ratios providing increased efficiency and improved power output per cylinder. The properties of methanol and ethanol result in different vehicle fuel storage considerations. Unlike gasoline or diesel fuel, the vapor of methanol or ethanol above the liquid fuel in a fuel tank is usually combustible at ambient temperatures. This poses the risk of an explosion should a spark or flame find its way to the tank such as during refueling. The 85% methanol–15% gasoline fuel in use in California and elsewhere is commonly called M85. If methanol is to compete with conventional gasoline and diesel fuel it must be readily available and inexpensively produced. Thus methanol production from a low‐cost feedstock such as natural gas or coal is essential. Ethanol is primarily produced from a variety of crops and crop by‐products, generically called renewable biomass. In general, the low cost estimates for alcohol fuels indicate that methanol produced on a large scale from low cost natural gas could compete with gasoline when oil prices are around 14¢/L ($27/bbl). The future market response to new forms of emissions regulation is unknown. It is possible that the new emissions standards will simply result in improved gasoline technologies, and that the market result of the new standards will simply be cleaner gasolines. However, in 1990 the U.S. Alternative Fuels Council agreed on a goal of a 25% share of nonpetroleum transportation fuels by 2005. Alcohol fuels could capture a large part of this 25% share of nonpetroleum fuels.
Aldehydes
Authors: Abatjoglou Anthony G. , Miller David J. 
Published: July 2004

AbstractAldehydes are carbonyl‐containing organic compounds of the general formula RCHO. The group R represents an aliphatic, aromatic, heterosubstituted radical, except in formaldehyde, where R represents hydrogen. Aldehydes are inherently reactive compounds. The carbonyl group is susceptible to both oxidation and reduction, yielding acids and alcohols, respectively. The common method of naming aldehydes corresponds very closely to that of the related acids in that the termaldehydeis added to the base name of the acid. The C1and C2carbon aliphatic aldehydes, formaldehyde and acetaldehyde, are gases at ambient conditions whereas the C3(propanal) through C11(undecanal) aldehydes are liquids, and higher aldehydes are solids at room temperature. The lower, C1to C8aldehydes have pungent, penetrating, unpleasant odors. Above C8, aldehydes have more pleasant odors and some higher aldehydes are used in the perfume and flavoring industries. Reactions of aldehydes generally fall into two classes: those directly affecting the carbonyl group and those involving the adjacent carbon atom. There are, acute effects of aldehydes: eye, skin, and respiratory tract irritation, as well as organ pathology. Aldehydes find the most widespread use as chemical intermediates. A large proportion of aldehydes are converted to alcohols for use as solvents and in the manufacture of plasticizers. Fatty aldehydes C8to C13are used in nearly all perfume types and aromas.
Alkanolamines from Nitro Alcohols
Authors: Eachus Alan C. , Bollmeier Allen F. 
Published: July 2004

Abstract
The nitro alcohols obtained by the condensation of nitroparaffins with formaldehyde may be reduced to a unique series of alkanolamines (β‐amino alcohols). The five primary amino alcohols manufactured on a commercially significant scale are 2‐amino‐2‐methyl‐1‐propanol (AMP), 2‐amino‐2‐ethyl‐1,3‐propanediol (AEPD), 2‐amino‐2‐(hydroxymethyl)‐1,3‐propanediol (TRIS AMINO), 2‐amino‐2‐methyl‐1,3‐propanediol (AMPD), and 2‐amino‐1‐butanol (AB). 2‐dimethylamino‐2‐methyl‐1‐propanol (DMAMP) is the only N‐substituted derivative of these compounds available in commercial quantities. These six commercial alkanolamines are highly soluble in water. They are generally very soluble in alcohols, slightly soluble in aromatic hydrocarbons, and nearly insoluble in aliphatic hydrocarbons. According to current U.S. Department of Transportation regulations, AMP, AMP‐95, DMAMP, DMAMP‐80, AEPD, and AB are all classified as combustible liquids. The commercial alkanolamines exhibit the chemical reactivity of both amines and alcohols, as do other alkanolamines. Typically, they will attack copper, brass, and aluminum, but not steel or iron. Alkanolamines are useful as amination agents. The reduction of nitro alcohols to alkanolamines is accomplished by hydrogenation in the presence of Raney nickel catalyst. Alkanolamines are only slightly toxic by ingestion. Undiluted DMAMP, AMP‐95, and AB cause eye burns and permanent damage if not washed out immediately. The 40% aqueous solution of TRIS AMINO is nonirritating to the eyes and skin. Alkanolamines are used in emulsions, pigment dispersion, resin solubilizers, catalysts, applications in oil and gas production, and in biomedical and synthetic applications.
Allyl Monomers and Polymers
Authors: Dowbenko R. 
Published: July 2004

AbstractAllyl compounds comprise a large group of ethylenic compounds having unique reactivities and uses often contrasting with those of typical vinyl‐type compounds. Unlike monovinyl compounds, monoallyl compounds do not form homopolymers of high molecular weight by free‐radical or conventional ionic mechanisms. In contrast, many allyl compounds containing two or more reactive double bonds yield solid, high molecular weight polymers by initiation with suitable free‐radical catalysts. A number of polyfunctional allyl esters have achieved importance in polymerization and copolymerization, especially to obtain heat‐resistant cast sheets and thermoset moldings. Diallyl diglycol carbonate or diethylene glycol bis(allyl carbonate) (DADC) was developed to produce by bulk polymerization cast sheets, lenses, and other shapes of outstanding scratch resistance and optical and mechanical properties. Reaction of allyl alcohol in the presence of alkali with diethylene glycol bis(chloroformate) gives the DADC monomer, a colorless liquid of mild odor. The latter is low in toxicity, but can produce skin irritation. DADC is soluble in common organic solvents and in methyl methacrylate, styrene, and vinyl acetate. It is partially soluble in amyl alcohol, gasoline, and ligroin. It is insoluble in ethylene glycol, glycerol, and water. Usage of DADC polymers in impact‐resistant, lightweight eyewear lenses has grown rapidly and is now the principal application. The three isomeric diallyl phthalates are colorless liquids of mild odor, low volatility, and relatively slow polymerization in the early stages. At ca 25% conversion, the viscous liquid undergoes gelation and polymerization accelerates. Diallyl isophthalate (DAIP) polymerizes faster than DAP. Besides application as heat‐resistant molding powders for electronic and other applications, DAIP copolymers have been proposed for optical applications. The largest use of diallyl phthalate thermoset polymers is in moldings and coatings for electronic devices requiring high reliability under long‐term adverse environmental conditions. Monomers such as allyl methacrylate (AMA) and diallyl maleate (DAM) have applications as cross‐linking and branching agents selected especially for the different reactivities of their double bonds. DAM and DAF have pungent odors and are skin irritants. Allyl methacrylate (AMA) is used as cross‐linking agent with methacrylate esters in contact lenses. Triallyl cyanurate (TAC), 2,4,6‐tris(allyloxy)‐s‐triazine, and its isomer triallyl isocyanurate (TAIC) are used as cross‐linking agents with comonomers and for aftercuring preformed polymers such as olefin copolymers in electrical insulations.N,N‐Diallyldimethyl(DADM)ammonium salts are used for the preparation of polyelectrolytes. Copolymers of diallyldimethylammonium chloride with acrylamide have been used in electroconductive coatings.
Fluorine Compounds, Inorganic, Aluminum
Authors: Conley B. , Shaikh T. , Atwood D. A. 
Published: July 2004

AbstractBoth the binary and complex fluorides of aluminum have played a significant role in the aluminum industry. Aluminum trifluoride trihydrate is of primary importance to the manufacture of aluminum as is sodium hexafluoroaluminate, known as cryolite. Anhydrous aluminum fluoride is used in fluoride glass manufacture and in ceramics. Mixtures of potassium tetrafluoroaluminate and potassium hexafluoroaluminate have been employed as brazing fluxes in the manufacture of aluminum parts. Two new types of aluminates with far ranging commercial potential have been prepared and characterized. The properties, manufacture, and uses of the various aluminum fluoride compounds are described.
Aminoglycosides
Authors: McGregor Donald 
Published: July 2004

AbstractAminoglycosidesare members of the class of antibacterial antibiotics, the structures of which are derived fromD‐streptamine,D‐2‐deoxystreptamine, or closely related compounds. The termaminocyclitolis sometimes used to identify this group of compounds. In 1991, the most widely used aminoglycosides in medical practice were gentamicin, tobramycin, amikacin, and netilmicin. In general, the aminoglycosides are useful for the treatment of serious infections involving aerobic or facultative gram‐negative bacilli. The most common resistance mechanism involves the inactivation of the aminoglycoside by reactions catalyzed by plasmid‐borne enzymes. Less common resistance mechanisms include decreased affinity for the antibiotic by the bacterial ribosome and decreased rate of transport into the bacterial cytoplasm. The aminoglycosides are administered primarily by intravenous infusion or intramuscular injection. Most of the administered dose is eliminated unmetabolized in the urine. Potential toxicity is a primary limiting factor in the clinical use of aminoglycosides. The most important toxicities are nephrotoxicity, ototoxicity, and to a lesser extent, neuromuscular blockade. All the aminoglycosides in medical practice are capable of causing these adverse events. The effect of this potential is to prevent the use of significantly increased doses to cover difficult infections. The bactericidal mechanisms employed by aminoglycosides are incompletely understood. In the cytoplasm, ribosomal binding leads to misreading of the genetic code and production of abnormal proteins and protein synthesis inhibition. The cause of cell death is uncertain. A large amount of research has been conducted aimed at reducing the limitations in the areas of toxicity and susceptibility to bacterial resistance mechanisms while maintaining the advantages by modification of the aminoglycoside molecular structure. Overall, structural modification has been successful in reducing susceptibility to bacterial inactivation. It has not been possible, however, to substantially dissociate the toxicity potential from the antibacterial activity.
Amines by Reduction
Authors: Schilling Steven L. 
Published: July 2004

Abstract
Amines are derivatives of ammonia in which one or more of the hydrogens is replaced with an alkyl, aryl, cycloalkyl or heterocyclic group. When more than one hydrogen has been replaced, the substituents can either be the same or different. Amines are classified as primary, secondary, or tertiary depending on the number of hydrogens which have been replaced. Many different types of nitrogen‐containing compounds can be reduced to amines. In practice, however, nitriles or nitro compounds are usually used because they are the most easily obtained starting materials. There are several commercial processes for reducing nitro or nitrile groups to amines. Most large volume aromatic and aliphatic amines are made by continuous high‐pressure catalytic hydrogenation. Nitro compounds can also be reduced in good yields with iron and hydrochloric acid in the Bèchamp process. Aromatic amines are usually made by hydrogenating the corresponding nitro compound, whereas the aliphatic amines generally start with the corresponding nitrile. In the Bèchamp process, nitro compounds are reduced to amines in the presence of iron and an acid. This is the oldest commercial process for preparing amines, and is still used in the dyestuff industry. The method of reducing aromatic nitro compounds with divalent sulfur is known as Zinin reduction. This reaction is carried out in a basic media using sulfides, polysulfides, or hydrosulfides as the reducing agent. Amines, nitro compounds, nitriles, and the various solvents and reagents used in the preparation of amines by reduction vary widely in the hazards they may pose. Some of these materials are acutely toxic by ingestion, inhalation, or absorption through the skin. Others are skin irritants or sensitizers. Still others, by chronic exposure, may cause damage to organs such as the liver or may be carcinogenic. No general rules can govern their safe use in all cases. Regulations governing the safe handling and shipping of amines are given in U.S. Department of Transportation publications. Specific information on safe handling and hazards can be found in the Material Safety Data Sheet for a given material.
Amino Resins and Plastics
Authors: Williams Laurence L. 
Published: July 2004

AbstractAmino resins are thermosetting polymers made by combining an aldehyde with a compound containing an amino (\documentclass{article}\usepackage{amssymb}\pagestyle{empty}\begin{document}${{\relbar \kern-5pt{\relbar}\kern-7pt{\relbar}}{\rm{NH}}{_{2}}}$\end{document}) group. Urea–formaldehyde (U/F) accounts for > 80% of amino resins; melamine–formaldehyde accounts for most of the rest. The principal attractions of amino resins and plastics are water solubility before curing; colorlessness; excellent solvent resistance; outstanding hardness and abrasion resistance; and good heat resistance. Amino resins provide a wide variety of useful products. Adhesives, the largest single market, are used to make plywood, chipboard, and sawdust board. Other types are used to make laminated wood beams, parquet flooring, and for furniture assembly. Aminoplasts and other thermosetting plastics are molded by an automatic injection‐molding process similar to that used for thermoplastics. The process is best applied to relatively small moldings. The great advantage of injection molding is that it eliminates manual labor costs, thereby allowing amino resins to better compete with thermoplastics. The future for amino resins and plastics seems secure. New developments will probably be in the areas of highly specialized materials for treating textiles, paper, etc, and for use with other resins in the formulation of surface coatings. Most amino resins are based on the reaction of formaldehyde with urea or melamine. The first step in the formation of resins and plastics from formaldehyde and amino compounds is the addition of formaldehyde to introduce the hydroxymethyl group, known as methylolation or hydroxymethylation. The second step is a condensation reaction that involves the linking together of monomer units with the liberation of water to form a dimer, a polymer chain, or a vast network, usually referred to as methylene bridge formation, polymerization, resinification, or simply cure. Precise control of the course, speed, and extent of the reaction is essential for successful manufacture. Amino resins are usually made by a batch process. Both urea– and melamine–formaldehyde resins are of low toxicity. Melamine–formaldehyde resins may be used in paper that contacts aqueous and fatty foods. However, some mills are looking for alternatives.
Ammonia
Authors: Eggeman Tim 
Published: July 2004

Abstract
Ammonia is a colorless gas, is lighter than air and has a unique penetrating odor. It occurs naturally throughout the universe. This article lists the import properties of ammonia and discusses its manufacture. Ammonia is produced mainly by the steam reforming of methane. This process is discussed in detail. Information on other production processes is given. Ammonia is a world‐class commodity. U.S. and global capacity data are presented along with a listing of U.S. producers. Ammonia produced by steam reforming is relatively clean, but ammonia produced from heavy feedstocks can cause environmental problems. Ammonia is a strong local irritant. The largest use for ammonia is in the production of fertilizers. It is also used to produce chemicals such as caprolactam, acrylonitrile and hydrogen cyanide.
Semiconductors, Amorphous Semiconductors
Authors: Madan Arun 
Published: July 2004

AbstractAmorphous hydrogenated silicon (a‐Si:H)‐based semiconductors dominate many application areas such as flat‐panel liquid crystal displays, high electrophotography, and photovoltaics. The uniqueness of amorphous silicon from a basic physics point of view is discussed with respect to its crystalline counterpart. The growth mechanism ofa‐Si:H using the plasma‐enhanced chemical vapor deposition (PECVD) technique and the interrelationship between some deposition parameters and the resulting optoelectronic properties of the film are outlined. This discussion is expanded to the use of these materials in various important applications and the primary companies involved in their manufacture.