Polycycles, aromatic, reduction

Reduction of fullerenes to fullerides — Reversible electrochemical reduction of Ceo in anhydrous dimethylformamide/toluene mixtures at low temperatures leads to the air-sensitive coloured anions Qo" , ( = 1-6). The successive mid-point reduction potentials, 1/2, at -60°C are -0.82, -1.26, -1.82, -2.33, —2.89 and —3.34 V, respectively. Liquid NH3 solutions can also be used. " Ceo is thus a very strong oxidizing agent, its first reduction potential being at least 1 V more positive than those of polycyclic aromatic hydrocarbons. C70 can also be reversibly reduced and various ions up to... 

Polycyclic Aromatic Compounds and Their Reduction Products... 

Aromatic rings can be reduced without difficulty. Major problems connected with these reductions concern maintenence of other functions, control of regioselectivity in polycyclic aromatics, and control of stereochemistry. 

Mineral oils also known as extender oils comprise of a wide range of minimum 1000 different chemical components (Figure 32.6) and are used extensively for reduction of compound costs and improved processing behaviors.They are also used as plastisizers for improved low temperature properties and improved rubber elasticity. Basically they are a mixture of aromatic, naphthanic, paraffinic, and polycyclic aromatic (PCA) materials. Mostly, 75% of extender oils are used in the tread, subtread, and shoulder 10%-15% in the sidewall approximately 5% in the inner Uner and less than 10% in the remaining parts for a typical PCR tire. In total, one passanger tire can contain up to 700 g of oil. 

Li, H. and Westerholm, R., Determination of mono- and di-nitro polycyclic aromatic hydrocarbons by on-line reduction and high-performance liquid chromatography with chemiluminescence detection, /. Chromatogr. A, 664,177, 1994. 

Bioventing technology was developed by the U.S. EPA Risk Reduction Engineering Laboratory to treat soil contaminated by numerous industrial wastes, which is subjected to aerobic microbial degradation, especially to promote the degradation of polycyclic aromatic hydrocarbons.65 It uses a series of air injection probes, each of which is attached to a low-pressure air pump. The air pump operates at extremely low pressures to allow the inflow of oxygen without volatilization of contaminants. Additional additives such as ozone or nutrients may also be supplied to stimulate microbial growth.77... 

McCarthy, J.F., Jimenez, B.D. (1985) Reduction in bioavailability to bluegills of polycyclic aromatic hydrocarbons bound to dissolved humic material. Environ. Toxicol. Chem. 4, 511-521. 

On treatment with a base such as NaOMe or even LLAIH4, mono-cycloadducts of mesitonitrile oxide and polycyclic aromatic hydrocarbons have been cleaved to yield the corresponding oximes, which are oxidized to ketones by the Dess— Martin method. The same ketones have been obtained by reductive ring opening of the mono-cycloadducts with Raney Ni (438). 

One consequence of the uptake of some contaminants is a reduction in the ability of lysosomes to retain the dye Neutral Red. As a consequence, the Neutral Red retention time has been developed as an index of lysosomal membrane fragility and thus of toxicity. The test has been used on the digestive cells involved with intracellular digestion of endocytosed food following administration of organic contaminants, such as polycyclic aromatic hydrocarbons [71]. The phenomenon has been reported many times after exposure to... 

Grundy, M. M., Moore, M. N., Howell, S. M. and Ratcliffe, N. A. (1996). Phagocytic reduction and effects on lysosomal membranes by polycyclic aromatic hydrocarbons, in haemocytes of Mytilus edulis, Aquat. Toxicol., 34, 273-290. 

Reduction potentials for polycyclic aromatic hydrocarbons in rigorously dried... 

The delocalised radical formed by protonation of the radical-anion is more easily reduced than the starting arene. For some polycyclic aromatic hydrocarbons, the redox potential for this radical species can be determined using a cyclic voltammetry technique [10]. Reduction in dimethylformamide is carried out to the potential for formation of the dianion. The dianion undergoes rapid monoprotonation and on the reverse sweep at a fast scan rate, oxidation of the monoanion to the radical can be observed. The radical intermediate from pyrene has E° = -1.15 V vs. see in dimethylformamide compared to E° = -2.13 V vs. see for pyrene,... 

---