Aromatic compounds isolation

Mechichi T, M Labat, J-L Garcia, P Thomas, BKC Patel (1999) Sporobacterium olearium gen. nov., sp. nov., a new methanethiol-producing bacterium that degrades aromatic compounds, isolated from an olive mill wastewater treatment digester. Int J Syst Bacteriol 49 1741-1748. 

Pfefferle W, Anke H, Bross M, Steglich W (1990) Inhibition of Solubilized Chitin Synthase by Chlorinated Aromatic Compounds Isolated from Mushroom Cultures. Agric Biol Chem 54 1381... 

Oshita, S. and Matsumoto, A. (2006) Fluorescence from aromatic compounds isolated in the solid state by double intercalation using layered polymer crystals as the host solid fluorescence from aromatic compounds isolated in the solid state by double intercalation using layered polymer crystals as the host solid. Langmuir, 22, 1943-1945. 

Catalytic hydrogenations over CojfCOjg (using Hj and CO) or with stoichiometric quantities of preformed hydridocarbonyl complex CoH(CO)4 are useful for the partial selective reductions of polycyclic aromatic compounds. Isolated benzene rings are not affected. Naphthalene is reduced to tetralin, at 200°C under a pressure of 20 X 10 kPa and anthracene to 9,10-dihydroanthracene (99%). The substituted phenanthrene nucleus is stable under these conditions as illustrated by hydrogenation of perylene 1 and pyrene 2. ... 

Trimethyl-l,3,5-dithiazine (thialdine) is an aromatic compound isolated from different meats <1997ZLUF73>. 

Examples of Polynuclear Aromatic Compounds Isolated from Coal... 

The catalyst is inactive for the hydrogenation of the (isolated) benzene nucleus and so may bo used for the hydrogenation of aromatic compounds containing aldehyde, keto, carbalkoxy or amide groups to the corresponding alcohols, amines, etc., e.g., ethyl benzoate to benzyl alcohol methyl p-toluate to p-methylbenzyl alcohol ethyl cinnamate to 3 phenyl 1-propanol. 

The transmetallation of various organometallic compounds (Hg, Tl, Sn, B, Si, etc.) with Pd(II) generates the reactive cr-aryl, alkenyl, and alkyl Pd compounds. These carbopalladation products can be used without isolation for further reactions. Pd(II) and Hg(II) salts have similar reactivity toward alkenes and aromatic compounds, but Hg(II) salts form stable mercuration products with alkenes and aromatic rings. The mercuration products are isolated and handled easily. On the other hand, the corresponding palladation products are too reactive to be isolated. The stable mercuration products can be used for various reactions based on facile transmetallation with Pd(II) salts to generate the very reactive palladation products 399 and 400 in rim[364,365]. 

It resembles tetracyanoethylene in that it adds reagents such as hydrogen (31), sulfurous acid (31), and tetrahydrofuran (32) to the ends of the conjugated system of carbon atoms suffers displacement of one or two cyano groups by nucleophilic reagents such as amines (33) or sodiomalononittile (34) forms TT-complexes with aromatic compounds (35) and takes an electron from iodide ion, copper, or tertiary amines to form an anion radical (35,36). The anion radical has been isolated as salts of the formula (TCNQ) where is a metal or ammonium cation, and n = 1, 1.5, or 2. Some of these salts have... 

Tnflic acid is an excellent catalyst for the nitration of aromatic compounds [.S7]. In a mixture with nitnc acid, it forms the highly electrophilic nitronium inflate, which can be isolated as a white crystalline solid Nitronium inflate is a powerful nitrating reagent in inert organie solvents and in tnflic acid or sulfuric acid. It nitrates benzene, toluene, chlorobenzene, nitrobenzene, m-xylene, and benzotn-fluoride quantitatively in the temperature range of-110 to 30 °C with exeeptionally high positional selectivity [87],... 

Friedel-Crafts acylation reactions usually involve the interaction of an aromatic compound with an acyl halide or anhydride in the presence of a catalyst, to form a carbon-carbon bond [74, 75]. As the product of an acylation reaction is less reactive than its starting material, monoacylation usually occurs. The catalyst in the reaction is not a true catalyst, as it is often (but not always) required in stoichiometric quantities. For Friedel-Crafts acylation reactions in chloroaluminate(III) ionic liquids or molten salts, the ketone product of an acylation reaction forms a strong complex with the ionic liquid, and separation of the product from the ionic liquid can be extremely difficult. The products are usually isolated by quenching the ionic liquid in water. Current research is moving towards finding genuine catalysts for this reaction, some of which are described in this section. 

The usual aromatic bromination are performed by free bromine in the presence of a catalyst, most often iron. However, liquid bromine is not easy to handle because of its volatile and toxic character. On the other hand, alumina-supported copper(II) bromide can be treated easily and safely as a solid brominating reagent for aromatic compounds. The advantages of this procedure using the solid reagent are simple workups, mild conditions, and higher selectivities. Products can be isolated in good yield by simple filtration and solvent evaporation, and no extraction steps are required. 

Aromatic organic chemistry is a special branch of organic chemistry because the six-membered carbon rings that define aromatic compounds are exceptionally stable and act as central supports to which other groups can be attached. The name aromatic was given to early isolated examples of these compounds because they have characteristic odors. 

Benzene and related aromatic compounds were hrst isolated from the gases given off during the heating of coal in the absence of air to produce a form of carbon known as coke, used in the manufacture of steel. That benzene had the molecular formula CgHg was determined in 1825, but it took over a hundred years to prove its structure even though its correct structure was suggested in 1865. 

Naphtha is a mixture of aliphatic hydrocarbons isolated from petroleum by distillation. When it is passed over a catalyst under the right conditions, carbon rings are formed, followed by the sphtting of hydrogen from the carbon rings to produce benzene, toluene, and other aromatic compounds. 

Monoalkylation products, 3-aryl-1,1 -dichloro-1 -silabutanes, were obtained from the alkylation of aromatic compounds with I in the presence of aluminum chloride catalyst in good isolated yields (60-80%) along with small amounts of higher alkylation products. Dialkylation products were obtained in yields ranging from 2 to 8% when a 5-fold excess of the aromatic compounds with respect to 1 was used. The amount of dialkylated products can be further reduced by using a greater excess of the aromatic compounds. 

Fredrickson JK, FJ Brockman, DJ Workmnan, SW Li, TO Stevens (1991) Isolation and characterization of a subsurface bacterium capable of growth on toluene, naphthalene, and other aromatic compounds. Appl Environ Microbiol 57 796-803. 

Grifoll M, SA Selifonov, CV Gatlin, PJ Chapman (1995) Actions of a versatile fluorene-degrading bacterial isolate on polycyclic aromatic compounds. Appl Environ Microbiol 61 3711-3723. 

Lomans BP, P Leijdekkers, J-P Wesselink, P Bakkes, A Pol, C van der Drift, HIP op den Camp (2001) Obligate sulfide-dependent degradation of methoxylated aromatic compounds and formation of methanethiol and dimethyl sulfide by a freshwater sediment isolate, Parasporobacterium paucivorans gen. nov., sp. nov. Appl Environ Microbiol 67 4017-4203. 

A general experimental procedure57 for a diarylmethane leuco compound via a benzotriazole To a stirred solution of the corresponding (benzotriazol-l-yl-methyl)aniline (5 mmol) in methanol (30 ml) under reflux was added a solution of the appropriate aromatic compound (5 mmol) and concentrated hydrochloric acid (1 ml) in water (30 ml). The resulting mixture was heated under reflux followed by the addition of aqueous KOH (1 M, 50ml). The product was isolated by filtration or by extraction with ether, and further purified by recrystallization or by column chromatography. 

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