Polycyclic terphenyls

Although many hydrocarbons exhibit fluorescence, often they are colourless and the fluorescence is only just into the blue, e.g. the linear terphenyl and quaterphenyl. Polycyclic ring systems such as terrylene and rubicene are used in analytical methods and OLEDs but a large number are ruled out of commercial use because of their potential to act as carcinogens. However, as mentioned in section 3.5.1.3, pery-lene is a useful fluorophore in a variety of outlets and pyrene is another polycyclic compound of interest. One derivative of pyrene (3.27) is a yellow-green fluorescent dye used in textile applications (Cl Solvent Green 7) and in analysis and sensors (see section 3.5.6.4). 

Specific requirements for the end products include tests and migration limits for various types of toxic or harmful compounds such as Michler s ketone (4,4 bis(dimethylamino)benzophenone), 4,4 bis(diethylamino) benzophenone (DEAB), diisopropyhiaphthalenes (DIPNs) phthalates, solvents, partially hydrogenated terphenyls (HTTP), azo colourants, fluorescent whitening agents, primary aromatic amines, polycyclic aromatic hydrocarbons (PAH) and benzophenone. The amounts of these substances should be either below the detection limits or, in some cases (DIPN, HTTP, solvents) as low as can be reasonably achieved. For benzophenone a specific migration limit of 0.1 mg/dm is defined. The requirements generally apply to products intended to be used in contact with aqueous and/or fatty foodstuffs or also with dry, non-fatty foodstuffs (requirements for DIPNs, HTTP, phthalates and solvents). 

PCDE PCDF PCN PCT PCTPM PER PMF POM POP PVC Polychlorinated diphenylethers Polychlorinated dibcnzofuranes Polychlorinated naphthalenes Polychlorinated terphenyls Polychlorinated triphenylmethanes T etrachloroethylene Polycyclic synthetic musk substitutes Particulate organic matter Persistent organic pollutant Polyvinyl chloride... 

Ozonation of benzo[r,s,t]pentaphene (7) followed by oxidative workup led to benzo[r,s,t]pentaphene-5,8-dione (12) (14%), phthalic acid (13) (4%), p-terphenyl-2,2, 3, 2"-tetra-carboxylic acid-2, 3 -anhydride (14) (10%), and 2-(o-car-boxyphenyl)- ,10-phenanthrenedicarboxylic acid anhydride (15) (3%), with a 56% recovery of unreacted 7, Ozonation of pentaphene (11) led to a peroxidic mixture which on oxidative workup led to 2,2 -binaphthyl-3,3 -dicarboxalde-hyde (16) (16%), 2,2 -binaphthyl-3,3 -dicarboxylic acid (17) (16%), and 13 (2%), with a 28% recovery of unreacted 11. A comparison of the reactivity to ozone of carcinogenic polycyclic aromatics benzo c]phenanthrene (1), 7,12-di-methylbenz [a] anthracene (2), 3-methylcholanthrene (3), dibenz[si,]] - (4), and dibenzlsi, ]anthracene (5), benzo Si -pyrene (6) and 7, and the noncarcinogen 11, all determined in our laboratory, leads us to conclude that there is no simple, consistent correlation between carcinogenicity, K-and L-region additivity towards ozone and the Pullmans electronic theory of carcinogenesis. 

Fig. 3 PAHs separation on alkylphosphonate-modified magnesia-zirconia composite (4-6 p.m, 150 mm x 4.6 mm I.D. column). Mobile phase methanol-water (75 25, v/v). 1—Solvent 2— Benzene 3 Toluene 4—Naphthalene 5 Biphenyl 6— Huorene 7 O-terphenyl 8— Af-terphenyl 9—P-terphenyL Source From Retention behavior of some polycyclic aromatic hydrocarbons on alkylphosphonate-modified magnesia-zirconia composite stationary phase for reversed-phase liquid chromatography, in Chin. J. Chromatogr. ...

On the basis of the preceding discussion, we proposed the following formation mechanism of OMCs [166], At OOO C, the products of benzene pyrolysis are known to be polycyclic aromatic hydrocarbon species, such as biphenyl, m-, p-, and o-terphenyls, and anthracene [155]. Such species first adsorb on the pore surfaces of SBA-15. Subsequently, further aromatization and carbonization of the adsorbed species takes place to form the first layer of carbon film [167,168], A layer-by-layer stacking then follows to create stacked graphene sheets. Thns, the favored direction of stacked graphene sheets is parallel to the long axis of the nanorods. Carbon deposition in the pores of the mesoporous silica template will stop when the pore size becomes smaller than the kinetic diameter of the benzene... 

Fig. 1. Structures of polycyclic compounds, (a) Polychlorinated (brominated) biphenyl (b) Polychlorinated (o-, m-, p-) terphenyl (c) Polychlorinated naphthalene (d) Polychlorinated dibenzofuran...

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