Several peri-naphthalenes are prepared via nitrations. Dinitration of naphthalene gives 1,8-dinitronaphthalene, which undergoes hydrogenation to the diamine. The diamine can also be produced by reaction of the 1,8-diol with ammonia at high temperatures. The peri- naphthalene 1-amino-naphthalene-8-sulfonic acid is a precursor to other peri- naphthalenes.
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Many naphthalenesulfonic acids and sulfonates are useful. Alkyl naphthalene sulfonate are surfactants, The aminonaphthalenesulfonic acids, naphthalenes substituted with Etherss and sulfonic acids, are intermediates in the preparation of many synthetic dyes. The hydrogenated naphthalenes tetrahydronaphthalene (tetralin) and decahydronaphthalene (decalin) are used as low-volatility solvents. Naphthalene sulfonic acids are also used in the synthesis of 1-naphthol and 2-naphthol, precursors for various dyestuffs, pigments, rubber processing chemicals and other chemicals and pharmaceuticals.
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Others include benzene, toluene, xylenes, cumenes, coumarone, indene, benzofuran, naphthalene and methyl-naphthalenes, acenaphthene, fluorene, phenol, cresols, pyridine, picolines, phenanthracene, carbazole, quinolines, fluoranthene. Many of these constituents are known carcinogens.
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Alkylated naphthalenes (methyl-, dimethyl-, and poly-methyl naphthalenes, thus including 2,6-DMN) are found in low concentrations in crude oil and coal tar. Separation is difficult, expensive, and requires a number of operations such as selective crystallization and adsorption, in addition to any isomerization reactions. There has been a search for suitable synthetic routes to 2,6-DMN. In the "alkenylation process" butadiene (1) , o-xylene (2), and Sodium-potassium alloy (3) are used, which react to form 5-(ortho- tolyl)pent-2-ene (OTP, 3). OTP is subsequently cyclized to 1,5-dimethyltetraline (4).
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Nye's products are based on a range of synthetic chemistries, including polyalphaolefins, esters, glycols, polyphenylethers, silicones, alkylated naphthalenes, and all commercially available perfluoropolyethers(PFPE). Nye is also the exclusive global reseller of Pennzane multiplyalkylated cyclopentane fluids, oils and greases.
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This benzannulation reaction creates previously unaccessed aromatic substitution patterns. A variety of substituted aromatic rings can be prepared using this method including: phenols, naphthalenes, benzofurans, benzothiophenes, indoles, and carbazoles. center The modified Danheiser benzannulation allows the synthesis of polycyclic aromatic and heteroaromatic systems.
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Polychlorinated naphthalenes, Preliminary Risk Profile.Ministry of VROM/DGM, Netherlands The material is an oil or a waxy solid, depending on the degree of chlorination. PCNs were once used in insulating coatings for electrical wires, as well as other applications, but their use has been largely phased out.
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Halowax is a New York-based company that was later owned by Union Carbide. It was subsequently taken over by Pittsburgh, Pennsylvania-based Koppers, which was later renamed Beazer East. It is the largest US producer of polychlorinated naphthalenes and polychlorinated biphenyls for floor finishing and similar applications.
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General structure of polychlorinated naphthalenes Structure of 2,3,6,7-Tetrachloronaphthalene Polychlorinated naphthalene (PCN) are the products obtained upon treatment of naphthalene with chlorine. The generic chemical formula is C10H8−(m+n)Cl(m+n). Commercial PCNs are mixtures of up to 75 components and byproducts.van de Plassche, E.; Schwegler, A. (2002).
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Because of this unusual structural feature, many unusual compounds are derived from peri-naphthalenes. One example is 1,8-bis(dimethylamino)naphthalene, known as proton sponge because of its high affinity for protons. Its ammonium derivative has a pKa of 12.7.Alexander F. Pozharskii and Valery A. Ozeryanskii "Proton sponges and hydrogen transfer phenomena" Mendeleev Commun.
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Soot is the primary cause of "ghosting", the discoloration of walls and ceilings or walls and flooring where they meet. It is generally responsible for the discoloration of the walls above baseboard electric heating units. The formation of soot depends strongly on the fuel composition. The rank ordering of sooting tendency of fuel components is: naphthalenes → benzenes → aliphatics.
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The first dye used commercially in this application was crystal violet lactone, which is widely used today. Other dyes and supporting chemicals used are PTSMH (p-toluene sulfinate of Michler's hydrol), TMA (trimellitic anhydride), phenol- formaldehyde resins, azo dyes, DIPN (diisopropyl naphthalenes), formaldehyde isocyanates, hydrocarbon-based solvents, polycyclic aromatic hydrocarbons, polyoxypropylene diamine, epoxy resins, aliphatic isocyanates, Bisphenol A, diethylene triamine, and others. The dyes in carbonless copy papers may cause contact dermatitis in sensitive persons.
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Chlorinated naphthalenes, International Programme on Chemical Safety CICAD, 2001, volume 34 There was a lag of about forty years between disclosure of PCN hazards and government regulation. In the U.S. exposure to PCNs was drastically reduced after 1976, following enactment of the Toxic Substances Control Act. Major equipment manufacturers banned PCNs in their products, and major PCN producers discontinued operations. By 1983 worldwide PCN production had almost halted except for small amounts used in testing and research.
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Additionally, there are environmental diseases caused by the aromatic carbon compounds including : benzene, hexachlorocyclohexane, toluene diisocyanate, phenol, pentachlorophenol, quinone and hydroquinone. Also included are the aromatic nitro-, amino-, and pyridilium-deratives: nitrobenzene, dinitrobenzene, trinitrotoluene, paramethylaminophenol sulfate (Metol), dinitro-ortho-cresol, aniline, trinitrophenylmethylnitramine (tetryl), hexanitrodiphenylamine (aurantia), phenylenediamines, and paraquat. The aliphatic carbon compounds can also cause environmental disease. Included in these are methanol, nitroglycerine, nitrocellulose, dimethylnitrosamine, and the halogenated hydrocarbons: methyl chloride, methyl bromide, trichloroethylene, carbon tetrachloride, and the chlorinated naphthalenes.
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PCNs started to be produced for high-volume uses around 1910 in both Europe and the United States.Chlorinated naphthalenes , Chemical Assessment Report S48, 2002, National Industrial Chemicals Notification and Assessment Scheme In Europe the largest volume products were called Nibren waxes, made in Germany by Bayer. Other European PCN tradenames included Seekay (UK, from ICI), Clonacire (France), Cerifal (Italy) and Woskol (Poland). In the United States, the largest volume PCN products were called Halowax, from a New York company of the same name that was later owned by Union Carbide and then taken over by Koppers of Pittsburgh, PA, now Beazer East.
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The Benkeser reduction reaction is the hydrogenation of polycyclic aromatic hydrocarbons, especially naphthalenes using lithium or calcium metal using low molecular weight alkyl amines as the solvent and, in part, as a source of protons. This reaction is a modification of the Birch reduction, where ammonia is the solvent. It offers the advantage that the reactions can be conducted at temperatures higher than the boiling point of ammonia (−33 °C).Institute of Chemistry, Skopje, Macedonia For the reduction naphthalene with lithium in a mixed ethylamine-dimethylamine solution, the principal products are bicyclo[3.3.0]dec-(1,9)-ene, bicyclo[3.3.
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PCBs were also commonly used as heat stabilizer in cables and electronic components to enhance the heat and fire resistance of PVC. In the 1930s, the toxicity associated with PCBs and other chlorinated hydrocarbons, including polychlorinated naphthalenes, was recognized because of a variety of industrial incidents. Between 1936 and 1937, there were several medical cases and papers released on the possible link between PCBs and its detrimental health effects. In 1936 a U.S. Public health Service official described the wife and child of a worker from the Monsanto Industrial Chemical Company who exhibited blackheads and pustules on their skin.
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Mixed bromochlorobiphenyls and polybrominated naphthalenes, as well as lower brominated compounds formed by incomplete bromination, have also been found as minor constituents of FireMaster products. In 1973, several thousand pounds of FireMaster BP-6 were accidentally mixed with livestock feed that was distributed to farms in Michigan, United States. Some 1.5 million chickens, 30,000 cattle, 5,900 pigs, and 1,470 sheep then consumed this feed, became contaminated with PBBs and the carcasses were disposed of in landfill sites throughout the state. In 1976, the Michigan Department of Community Health established a PBB registry to gather and analyze data on exposed residents.
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In organic chemistry, peri-naphthalenes are particular derivatives of naphthalene with the formula C10H6-1,8-X2. Owing to the rigidity of the naphthalene skeleton, these substituents on the 1- and 8-positions are constrained to be relatively close 2.5 Å, which is within the van der Waals radius for many atoms. In contrast, ortho-substituents pendant from a benzene ring are separated by about 3.3 Å.Kilian, P.; Knight, F. R.; Woollins, J. D., "Synthesis of ligands based on naphthalene peri-substituted by Group 15 and 16 elements and their coordination chemistry", Coordination Chemistry Reviews 2011, volume 255, 1387-1413.
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After about twenty years of commercial production, health hazards began to be reported in workers exposed to PCNs: chloracne, severe skin rashes and liver disease that led to deaths of workers.Chronic exposure increases risk of liver disease. See Chlorinated naphthalenes exposure, Worker Notification Program, National Institute for Occupational Safety and Health A conference about the hazards was organized at Harvard School of Public Health in 1937, and several more publications dealing with PCN hazards appeared before 1940. PCNs containing three or more chlorines per molecule have typically been found more hazardous than those with fewer, but as the maximum of eight is approached, hazards appear to decrease.
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In 2013, the 9th meeting of the Persistent Organic Pollutants Review Committee, established under the Stockholm Convention on Persistent Organic Pollutants proposed di-,tri-,tetra-,penta-,hexa-, hepta- and octa-chlorinated napthalenes, for listing in Annexes A and C to that Convention.UNEP (2013). Risk management evaluation on chlorinated naphthalenes, Report of the Persistent Organic Pollutants Review Committee on the work of its ninth meeting, Rome, 14–18 October 2013 (Addendum) While some PCNs can be broken down by sunlight and, at slow rates, by certain microorganisms, many PCNs persist in the environment. After more than 80 years of use and total production of several hundred thousand tons, PCN residues are widespread.
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Mentzel studied and gained B.Sc. in Mathematics and B.S. in Chemistry at the University of Göttingen, and he received his doctorate in 1925 with a thesis on Stereoisomerism and transformation of b-substituted decahydro-naphthalenes. At Göttingen, he was a Kreisleiter (circuit leader) of the Nationalsozialistische Deutsche Arbeiterpartei (NSDAP, National Socialist Workers Party), of which he had been a member since 1922. Due to his participation in the Kapp putsch in 1920, he held a golden party badge. Mentzel completed his Habilitation in 1933 at the Justus Liebig-Universität Gießen with a top-secret Habilitationsschrift (thesis) on Wehrchemie (military chemistry - the military use of poison gases).
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In Japan, methamphetamine seizures are usually white crystals of high purity, but contain impurities that vary according to the means of production, and are sometimes adulterated. Diagnostic impurities are the naphthalenes 1-benzyl-methylnaphthalene and 1,3-dimethyl-2-phenylnaphthalene, arising in the Nagai and Leuckart routes, and cis- or trans- 1,2-dimethyl-3-phenylaziridine, ephedrine, or erythro-3,4-dimethyl- 5-phenyloxazolidine, arising in the Nagai and Emde routes; these are absent in the reductive amination route. Characteristic impurities of the Birch route include N-methyl-1-(1-(1,4-cyclohexadienyl))-2-propanamine. Methamphetamine produced by the Birch route contains phenyl-2-propanone, the precursor for the reductive amination route, as a degradation product.
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JP-7 is a compound mixture composed primarily of hydrocarbons; including alkanes, cycloalkanes, alkylbenzenes, indanes/tetralins, and naphthalenes; with addition of fluorocarbons to increase its lubricant properties, an oxidizing agent to make it burn more efficiently, and a caesium-containing compound known as A-50, which is to aid in disguising the radar and infrared signatures of the exhaust plume. The SR-71 Blackbirds used approximately of fuel per hour of flight. JP-7 is unusual in that it is not a conventional distillate fuel, but is created from special blending stocks in order to have very low (<3%) concentration of highly volatile components like benzene or toluene, and almost no sulfur, oxygen, and nitrogen impurities. It has a low vapor pressure, and high thermal oxidation stability.
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This theorem would describe naphthalene as an aromatic benzene unit bonded to a diene but not extensively conjugated to it (at least in the ground state), which is consistent with two of its three resonance structures. :Resonance structures of naphthalene Because of this resonance, the molecule has bilateral symmetry across the plane of the shared carbon pair, as well as across the plane that bisects bonds C2-C3 and C6-C7, and across the plane of the carbon atoms. Thus there are two sets of equivalent hydrogen atoms: the alpha positions, numbered 1, 4, 5, and 8, and the beta positions, 2, 3, 6, and 7. Two isomers are then possible for mono-substituted naphthalenes, corresponding to substitution at an alpha or beta position. Bicyclo[6.2.
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They have also been detected in electronic wastes, workshop-floor dust, vegetation, and surface soil collected from the vicinity of an electronic waste (e-waste) recycling facility and in surface soil from a chemical industrial complex (comprising a coke-oven plant, a coal-fired power plant, and a chlor-alkali plant), and agricultural areas in central and eastern China. In addition, the combustion of polyvinylchloride and plastic wrap made from polyvinylidene chloride result in the production of Cl-PAHs, suggesting that combustion of organic materials including chlorine is a possible source of environmental pollution. A specific class of Cl-PAHs, polychlorinated naphthalenes (PCNs), are persistent, bioaccumulative, and toxic contaminants that have been reported to occur in a wide variety of environmental and biological matrixes. Cl-PAHs with three to five rings have been reported to occur in air from road tunnels, sediment, snow, and kraft pulp mills.
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Haloaromatics include the former Aroclors (Monsanto Company trademark for polychlorinated biphenyls, PCBs), once widely used in power transformers and capacitors and in building caulk, the former Halowaxes (Union Carbide trademark for polychlorinated naphthalenes, PCNs), once used for electrical insulation, and the chlorobenzenes and their derivatives, used for disinfectants, pesticides such as dichloro-diphenyl-trichloroethane (DDT, 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane), herbicides such as 2,4-D (2,4-dichlorophenoxyacetic acid), askarel dielectrics (mixed with PCBs, no longer used in most countries), and chemical feedstocks. A few halocarbons, including acid halides like acetyl chloride, are highly reactive; these are rarely found outside chemical processing. The widespread uses of halocarbons were often driven by observations that most of them were more stable than other substances. They may be less affected by acids or alkalis; they may not burn as readily; they may not be attacked by bacteria or molds; or they may not be affected as much by sun exposure.
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Any 4-substituted pyridine, pyridine itself, 1-substituted pyrazinium ion, diazine, 1-substituted or unsubstituted pyrrole and related aromatic heterocyclics (phospholes, furan, thiophene, etc.) as well as unsubstituted or 1-substituted cyclopentadienes and 1-substituted cyclopentadienides all have the same symmetry framework as para-disubstituted or ortho-homodisubstituted benzenes, and will present chemically equivalent but magnetically inequivalent pairs of protons. In heterocycles and in five- membered rings in general, however, 3J values can be significantly smaller than in benzenes and the manifestation of magnetic inequivalence may be subtle. The rarer seven-membered and higher ring systems may also show the same symmetry property, as can linked and fused aromatic ring systems such as biphenyls, naphthalenes and isoindoles. Similarly, 1-H benzimidazoles have the appropriate symmetry if N1-deprotonated or N3-protonated, or as a result of rapid tautomerization of the neutral form (for instance, in DMSO-d6) where the signals greatly resemble those of 1,2-dichlorobenzene.
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