Commercial sources

There are numerous manufacturers of basic carbon black. A partial list would include Akzo Nobel, Cabot Corp., Columbian Chemicals, Chevron-Phillips, and Degussa Corp. Most manufacturers describe the various grades they produce on their web sites. 

As with many fillers, colorants, and additives, CB is frequently compounded with a thermoplastic to form a concentrate or masterbatch that is then let down and dispersed in a chosen polymer to the final desired concentration. Masterbatches are available from a variety of compounders including Americhem, Inc., Ampacet Corp., 

Carbon black DBPA (cm /IOOg) Weight % of each shape category 12 3 4  

After Ref [8], reprinted with permission from Marcel Dekker, Inc. 

Note N designates ftimace blacks with normal curing in rubber compounds. The first digit after N relates to partide size or surface area. The second and third numbers are arbitrary grade designators. 

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These limitations have recently been eliminated using solid-state sources of femtosecond pulses. Most of the femtosecond dye laser teclmology that was in wide use in the late 1980s [11] has been rendered obsolete by tliree teclmical developments the self-mode-locked Ti-sapphire oscillator [23, 24, 25, 26 and 27], the chirped-pulse, solid-state amplifier (CPA) [28, 29, 30 and 31], and the non-collinearly pumped optical parametric amplifier (OPA) [32, 33 and 34]- Moreover, although a number of investigators still construct home-built systems with narrowly chosen capabilities, it is now possible to obtain versatile, nearly state-of-the-art apparatus of the type described below Ifom commercial sources. Just as home-built NMR spectrometers capable of multidimensional or solid-state spectroscopies were still being home built in the late 1970s and now are almost exclusively based on commercially prepared apparatus, it is reasonable to expect that ultrafast spectroscopy in the next decade will be conducted almost exclusively with apparatus ifom conmiercial sources based around entirely solid-state systems. 

Reaching tire goal of tire ideal nanocrystal sample is not an easy task. There are few commercial sources for nanocrystals, and tire chemical reactions used to make them can require involved syntlietic metliodology. On tire otlier hand, tire last decade has seen enonnous progress in tliis area and many solids have now been prepared in tire... 

Academic and other nonprofit institutions can get MM3 from qcpe.chem.indiana. edu. The commercial source is Tripos Inc., 1699 South Hanley Road, St. Louis, MO 63144. For resources on MM3 and MM4 see references 1-3 in Langley, C. H. and Allinger, N. L., J. Phys. Chem. 2003, 107, 5208-5216. 

Beryllium is found in some 30 mineral species, the most important of which are bertrandite, beryl, chrysoberyl, and phenacite. Aquamarine and emerald are precious forms of beryl. Beryl and bertrandite are the most important commercial sources of the element and its compounds. Most of the metal is now prepared by reducing beryllium fluoride with magnesium metal. Beryllium metal did not become readily available to industry until 1957. 

The element is much more abundant than was thought several years ago. It is now considered to be the 16th most abundant element in the earth s crust. Rubidium occurs in pollucite, leucite, and zinnwaldite, which contains traces up to 1%, in the form of the oxide. It is found in lepidolite to the extent of about 1.5%, and is recovered commercially from this source. Potassium minerals, such as those found at Searles Lake, California, and potassium chloride recovered from the brines in Michigan also contain the element and are commercial sources. It is also found along with cesium in the extensive deposits of pollucite at Bernic Lake, Manitoba. 

The element occurs along with other rare-earth elements in a variety of minerals. Monazite and bastnasite are the two principal commercial sources of the rare-earth metals. It was prepared in relatively pure form in 1931. 

Finally, if one simply cannot find the thing one needs then it s time to hit the bibles of industrial and commercial sources "Chemical Buyers Weekly", "Chemsource U.S.A." and the massive "Thomas Register". These three source books can be found at most libraries and contain the listings and services of just about every business in the country. No matter what the chemist needs, it can be found in these books. Even if it takes going one-by-one through the listings, Strike can assure you that the chemist will find what she needs and someone that will sell it to her. 

Butyrolactone. y-Butyrolactone [96-48-0] dihydro-2(3H)-furanone, was fkst synthesized in 1884 via internal esterification of 4-hydroxybutyric acid (146). In 1991 the principal commercial source of this material is dehydrogenation of butanediol. Manufacture by hydrogenation of maleic anhydride (147) was discontinued in the early 1980s and resumed in the late 1980s. Physical properties are Hsted in Table 4. 

Common name CAS Registry Number Molecular formula Bromine, % Specific gravity Mp, °C Commercial sources... 

The ores of most importance are fluorspar, CaF2 fluorapatite, Ca (P0 2Fj cryoHte [15096-52-3], Na AlF. Fluorspar is the primary commercial source of fluoiine. Twenty-six percent of the world s high quaHty deposits of fluorspar are ia North America. Most of that is ia Mexico. United States production ia 1987—1991 was 314,500 metric tons, most of which occurred ia the Illinois-Kentucky area. Imported fluorspar ia 1990—1991 represented about 82% of U.S. consumption 31% of U.S. fluorspar imports were from Mexico and 29% from China compared to 66% from Mexico ia the 1973—1978 period. The majority of the fluorine ia the earth s cmst is ia phosphate rock ia the form of fluorapatite which has an average fluorine concentration of 3.5%. Recovery of these fluorine values as by-product fluorosiHcic acid from phosphate production has grown steadily, partially because of environmental requirements (see Phosphoric acid and THE phosphates). 

Its powerful oxidizing properties result from the tight binding of its valence sheU 7-orbital electrons. No commercial source is available. 

In 1937 the first commercial apphcation of the Lefort direct ethylene oxidation to ethylene oxide [73-21-8] followed by hydrolysis of ethylene oxide became, and remains in the 1990s, the main commercial source of ethylene glycol production (1) (see Ethylene oxide). Ethylene oxide hydrolysis proceeds with... 

Pectin. Pectin [9000-69-5] is a generic term for a group of polysaccharides, mainly partially methoxylated polygalacturonic acids, which are located in the cell walls of all plant tissues. The main commercial sources of pectin are citms peel and apple pomace, where it represents 20—40% and 10—20% of the dry weight respectively. The pectin is extracted, the extract purified, and the pectin precipitated (50) increased extraction times lead to the production of low methoxyl pectins. 

Psyllium Seed Gum. PsyUium seed gum [8036-16-9] is derived from plants of the genus Plantago several species of which are used as commercial sources. However, most current production is from Plantago ovata grown in India. The gum is located in the coat which is removed by cracking. The gum is then extracted with boiling water and separated from the insoluble residue by filtration. It consists of mixtures of both neutral and acidic polysaccharides, the composition of which is species dependent (66). 

As with all tests, frequent caUbration of the test equipment using standard hardness blocks is a prerequisite for rehable hardness testing (see ASTM E18). Standard hardness blocks are available through commercial sources in the United States but do not have traceabiUty to internationally accepted standards as in Europe. 

The main commercial source of methane, ethane, and propane is natural gas, which is found ia many areas of the world ia porous reservoirs they are associated either with cmde oil (associated gas) or ia gas reservoirs ia which no oil is present (nonassociated gas). These gases are basic raw materials for the organic chemical industry as well as sources of energy. The composition of natural gas varies widely but the principal hydrocarbon usually is methane (see Gas, natural). Compositions of typical natural gases are Hsted ia Table 2. 

Occurrence. (R-R, R )-Tartaric acid occurs in the juice of the grape and in a few other fmits and plants. It is not as widely distributed as citric acid or S(—)-mahc acid. The only commercial source is the residues from the wine industry. (i -R, R -Tartaric acid has been found in the fmit and leaves of BauMma reticulata, a tree native to MaU (western Africa). Like the dextrorotatory acid, it forms anhydrous monoclinic crystals. 

California and Minnesota have placed restrictions on the disposal of fluorescent light tubes, which contain from 40—50 mg of mercury per tube, depending on size. After batteries, fluorescent lamps are the second largest contributor of mercury in soHd waste streams in the United States (3,14). A California law classifies the disposal of 25 or more fluorescent lamp tubes as hazardous waste. In Minnesota, all waste lamps generated from commercial sources are considered hazardous waste. Private homes are, however, exempt from the law (14). Other states have proposed similar regulations. Several companies have developed technologies for recovering mercury from spent lamps (14). 

Four minerals are the principal commercial sources of potash (Table 2). In all ores, sodium chloride is the principal soluble contaminant. Extraneous water-iasoluble material, eg, clay and siUca, is a significant contaminant ia some of the evaporates being mined from underground deposits. Some European potassium ores contain relatively large amounts of the mineral kieserite, MgS04-H2 0. It is recovered for captive use to produce potassium sulfate compounds or is marketed ia relatively pure form as a water-soluble magnesium fertilizer. 

Myrcene Manufacture. An important commercial source for mycene is its manufacture by pyrolysis of p-piaene at 550—600°C (87). The thermal isomerization produces a mixture of about 75—77 wt % myrcene, 9% limonene, a small amount of T -limonene [499-97-8] and some decomposition products and dimers. The cmde mixture is usually used without purification for the production of the important alcohols nerol and geraniol. Myrcene may be purified by distillation but every precaution must be taken to prevent polymerization. The use of inhibitors and distillation at reduced pressures and moderate temperatures is recommended. Storage or shipment of myrcene in any purity should also include the addition of a polymerization inhibitor. 

Side-Chain Derivatization. Reaction of thiophene with aqueous formaldehyde solution in concentrated hydrochloric acid gives 2-chloromethylthiophene [765-50-4]. This relatively unstable, lachrymatory material has been used as a commercial source of further derivatives such as 2-thiopheneacetonitrile [20893-30-5] and 2-thiopheneacetic acid [1918-77-0] (24). Similar derivatives can be obtained by peroxide, or light-catalyzed (25) halogenation of methylthiophenes, eg, Ai-bromosuccinimide/benzoylperoxide on 2-, and 3-methylthiophenes gives the corresponding bromomethylthiophenes. 

R)-Pantothenic acid (1) contains two subunits, (R)-pantoic acid and P-alanine. The chemical abstract name is A/-(2,4-dihydroxy-3,3-dimethyl-l-oxobutyl)-P-alanine (11). Only (R)-pantothenic acid is biologically active. Pantothenic acid is unstable under alkaline or acidic conditions, but is stable under neutral conditions. Pantothenic acid is extremely hygroscopic, and there are stabiUty problems associated with the sodium salt of pantothenic acid. The major commercial source of this vitamin is thus the stable calcium salt (3) (calcium pantothenate). 

Vitamin D [1406-12-2] is a material that is formed ia the skin of animals upon kradiation by sunlight and serves as a precursor for metaboUtes that control the animal s calcium homeostasis and act ki other hormonal functions. A deficiency of vitamin D can cause rickets, as weU as other disease states. This tendency can be a problem wherever animals, including humans, especially kifants and children, receive an kiadequate amount of sunshine. The latter phenomenon became prevalent with the advent of the kidustrial revolution, and efforts to cute rickets resulted ki the development of commercial sources of vitamin D for supplementation of the diet of Hvestock, pets, and humans. 

Fish-hver oil, Hver, milk, and eggs are good natural sources of the D vitamin. Most milk sold in the United States is fortified with manufactured vitamin D. Fish oil is the only commercial source of natural vitamin D, and the content of the vitamin varies according to species as well as geographically, ie, Adantic cod contain 100 lU/g where lU (International Unit) = 0.025 /ig of vitamin D, whereas oriental tuna (Percomofpk) contain 45,000 lU/g oil. 

In addition to its industrial importance as an intermediate in the synthesis of vitamin K, menadione, or more specifically, salts of its bisulfite adduct, are important commodities in the feed industry and are used as stabilized forms in this appHcation. Commercially significant forms are menadione dimethyl pyrimidinol (MPB) (10) and menadione sodium bisulfite (MSB) (11). MSB is sold primarily as its sodium bisulfite complex. The influence of feed processing, ie, pelleting, on the stabiUty of these forms has been investigated (68). The biological availabiUties and stabiUty of these commercial sources has been deterrnined (69,70). 

Oil Repellent. Fluorochemicals are the only class of material that can provide oil repeUency without altering the porosity of the paper or paperboard. Physical barriers to oil penetration are used primarily for their moisture- or gas-barrier properties, with retarded oil penetration as a secondary benefit. The most common od-repeUent additives are long-chain perfluoroalkyl phosphate salts of ammonia or diethanol amine. Commercial sources include Scotchban (3M), Zonyl (DuPont), and Lodyne (Ciba Specialties). There are also a fluorochemical carboxylate salt, Lodyne (Ciba Specialties), and fluorochemical copolymers, eg, Scotchban (3M). The widest range of oily fluid holdout is provided by the fluorochemical copolymers. 

Zirconium is found in at least 37 different mineral forms (6) but the predorninant commercial source is the mineral zircon, zirconium orthosiUcate. Other current mineral sources are baddeleyite and eudialyte [12173-26-1]. 

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