Aromatic compounds are those chemical compounds that contain one or more rings with pi electrons delocalized all the way around them. In contrast to compounds that exhibit aromaticity, aliphatic compounds lack this delocalization. The term "aromatic" was assigned before the physical mechanism determining aromaticity was discovered, and referred simply to the fact that many such compounds have a sweet or pleasant odour; however, not all aromatic compounds have a sweet odour, and not all compounds with a sweet odour are aromatic compounds. Aromatic hydrocarbons, or arenes, are aromatic organic compounds containing solely carbon and hydrogen atoms. The configuration of six carbon atoms in aromatic compounds is called a "benzene ring", after the simple aromatic compound benzene, or a phenyl group when part of a larger compound.
Naphthalene is an organic compound with formula C
10H
8. It is the simplest polycyclic aromatic hydrocarbon, and is a white crystalline solid with a characteristic odor that is detectable at concentrations as low as 0.08 ppm by mass. As an aromatic hydrocarbon, naphthalene's structure consists of a fused pair of benzene rings. It is best known as the main ingredient of traditional mothballs.
Phthalic acid is an aromatic dicarboxylic acid, with formula C6H4(CO2H)2. It is an isomer of isophthalic acid and terephthalic acid. Although phthalic acid is of modest commercial importance, the closely related derivative phthalic anhydride is a commodity chemical produced on a large scale. Phthalic acid is one of three isomers of benzenedicarboxylic acid, the others being isophthalic acid and terephthalic acid.
Phthalic anhydride is the organic compound with the formula C6H4(CO)2O. It is the anhydride of phthalic acid. Phthalic anhydride is a principal commercial form of phthalic acid. It was the first anhydride of a dicarboxylic acid to be used commercially. This white solid is an important industrial chemical, especially for the large-scale production of plasticizers for plastics. In 2000, the worldwide production volume was estimated to be about 3 million tonnes per year.
Isophthalic acid is an organic compound with the formula C6H4(CO2H)2. This colorless solid is an isomer of phthalic acid and terephthalic acid. The main industrial uses of purified isophthalic acid (PIA) are for the production of polyethylene terephthalate (PET) resin and for the production of unsaturated polyester resin (UPR) and other types of coating resins.
The Kolbe–Schmitt reaction or Kolbe process is a carboxylation chemical reaction that proceeds by heating sodium phenoxide with carbon dioxide under pressure, then treating the product with sulfuric acid. The final product is an aromatic hydroxy acid which is also known as salicylic acid.
Decalin, a bicyclic organic compound, is an industrial solvent. A colorless liquid with an aromatic odor, it is used as a solvent for many resins or fuel additives. It is the saturated analog of naphthalene and can be prepared from it by hydrogenation in the presence of a catalyst. Decalin easily forms explosive organic peroxides upon storage in the presence of air.
Polyethylene naphthalate is a polyester derived from naphthalene-2,6-dicarboxylic acid and ethylene glycol. As such it is related to poly(ethylene terephthalate), but with superior barrier properties.
Arene substitution patterns are part of organic chemistry IUPAC nomenclature and pinpoint the position of substituents other than hydrogen in relation to each other on an aromatic hydrocarbon.
Armstrong's acid (naphthalene-1,5-disulfonic acid) is a fluorescent organic compound with the formula C10H6(SO3H)2. It is one of several isomers of naphthalenedisulfonic acid. It a colorless solid, typically obtained as the tetrahydrate. Like other sulfonic acids, it is a strong acid. It is named for British chemist Henry Edward Armstrong.
2-Naphthol, or β-naphthol, is a fluorescent colorless (or occasionally yellow) crystalline solid with the formula C10H7OH. It is an isomer of 1-naphthol, differing by the location of the hydroxyl group on the naphthalene ring. The naphthols are naphthalene homologues of phenol, but more reactive. Both isomers are soluble in simple alcohols, ethers, and chloroform. 2-Naphthol is a widely used intermediate for the production of dyes and other compounds.
1,8-Diaminonaphthalene is an organic compound with the formula C10H6(NH2)2. It is one of several isomeric naphthalenediamines. It is a colorless solid that darkens in air due to oxidation. It is a precursor to commercial pigments.
1-Naphthol, or α-naphthol, is a fluorescent organic compound with the formula C10H7OH. It is a white solid. It is an isomer of 2-naphthol differing by the location of the hydroxyl group on the naphthalene ring. The naphthols are naphthalene homologues of phenol, with the hydroxyl group being more reactive than in the phenols. Both isomers are soluble in simple alcohols, ethers, and chloroform. They are precursors to a variety of useful compounds. Naphthols (both 1 and 2 isomers) are used as biomarkers for livestock and humans exposed to polycyclic aromatic hydrocarbons.
1,4-Naphthoquinone or para-naphthoquinone is an quinone derived from naphthalene. It forms volatile yellow triclinic crystals and has a sharp odor similar to benzoquinone. It is almost insoluble in cold water, slightly soluble in petroleum ether, and more soluble in polar organic solvents. In alkaline solutions it produces a reddish-brown color. Vitamin K is a derivative of 1,4-naphthoquinone. It is a planar molecule with one aromatic ring fused to a quinone subunit. It is an isomer of 1,2-naphthoquinone.
2,6-Dimethylnaphthalene (2,6-DMN) is a polycyclic aromatic hydrocarbon. It is one of the ten dimethylnaphthalene isomers, which are derived from naphthalene by the addition of two methyl groups.
1,5-Dihydroxynaphthalene is an organic compound with the formula C10H6(OH)2. It is one of several isomers of dihydroxynaphthalene. It exists as colorless crystals that are soluble in polar organic solvents. It is a precursor to certain dyes.
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.
Naphthalene-2-sulfonic acid is an organic compound with the formula C10H7SO3H. A colorless, water-soluble solid, it is often available as the mono- and trihydrates C10H7SO3H.2H2O. It is one of two monosulfonic acids of naphthalene, the other being naphthalene-1-sulfonic acid. The compound is mainly used in the production of dyes via nitration en route to aminonaphthalenesulfonic acids. The compound is prepared by sulfonation of naphthalene with sulfuric acid, however under equilibrating conditions that allow the 1-sulfonic acid isomer to convert to the more stable 2-sulfonic acid.
1,5-Diaminonaphthalene is an organic compound with the formula C10H6(NH2)2. It is one of several diaminonaphthalenes. It is a colorless solid that darkens in air due to oxidation.
1,8-Naphthalic anhydride is an organic compound with the formula C10H6(C2O3). It is one of three isomers of naphthalic anhydride, the other two being the 1,2- and the 2,3-derivatives. The 1,8-isomer is prepared by aerobic oxidation of acenaphthene. 2,6-naphthalenedicarboxylic acid can be prepared from this anhydride. 1,8-Naphthalic anhydride is a precursor to the 4-chloro and 4,5-dichloro derivatives. These chloride groups are susceptible to displacement by amines and alkoxides, giving rise, ultimately, to a large family of naphthalimides, which are used as optical brighteners.
