Diphenyl properties

Brominated Diphenyl Oxides. Brominated diphenyl oxides are prepared by the bromination of diphenyl oxide. They are often referred to as diphenyl ethers. Taken together, the class constitutes the largest volume of brominated flame retardants. They range ia properties from high melting sohds to hquids. They are used, as additives, ia virtually every polymer system. 

Octabromodiphenyl Oxide. Octabromodiphenyl oxide [32536-52-0] (OBDPO) is prepared by bromination of diphenyl oxide. The degree of bromination is controlled either through stoichiometry (34) or through control of the reaction kinetics (35). The melting poiat and the composition of the commercial products vary somewhat. OBDPO is used primarily ia ABS resias where it offers a good balance of physical properties. Poor uv stabiUty is the primary drawback and use ia ABS is being supplanted by other brominated flame retardants, primarily TBBPA. 

Tris(2-ethylhexyl) phosphate shows good compatibiUty with PVC and also imparts good low temperature performance in addition to good fire retardancy. 2-Ethyhexyl diphenyl phosphate has widespread use in dexible PVC appHcations due to its combination of properties of plasticizing efficiency, low temperature performance, migration resistance, and fire retardancy. 

Sulfonation has been used to change some characteristics of blends. Poly(2,6-diphenyl-l,4-phenylene oxide) and polystyrene are immiscible. However, when the polymers were functionalized by sulfonation, even though they remained immiscible when blended, the functionalization increased interfacial interactions and resulted in improved properties (65). In the case of DMPPO and poly(ethyl acrylate) the originally immiscible blends showed increased miscibility with sulfonation (66). 

Solubility. Another desirable property of a degradant is its high solubihty in mbber but poor solubihty in water and solvents that come in contact with mbber. Poor solubihty in the mbber means that only small quantities of antioxidants can be dissolved without producing a bloom. As an example, N,lSf-diphenyl- phenylenediamine (DPPD) has limited use because of its poor solubihty in mbber. On the other hand, phenohc and phosphite antioxidants have high solubihty and bloom is not a problem. 

In theory, three isoxazolines are capable of existence 2-isoxazoline (2), 3-isoxazoline and 4-isoxazoline. The position of the double bond may also be designated by the use of the prefix A with an appropriate numerical superscript. Of these only the 2-isoxazolines have been investigated in any detail. The preparation of the first isoxazoline, 3,5-diphenyl-2-isoxazoline, from the reaction of )3-chloro-)3-phenylpropiophenone with hydroxylamine was reported in 1895 (1895CB957). Two major syntheses of 2-isoxazolines are the cycloaddition of nitrile A-oxides to alkenes and the reaction of a,/3-unsaturated ketones with hydroxylamine. Since 2-isoxazolines are readily oxidized to isoxazoles and possess some of the unique properties of isoxazoles, they also serve as key intermediates for the synthesis of other heterocycles and natural products. 

Benzo[b]furan, 3-(2-hydroxy-3,5-dichlorophenyl)-5,7-dichloro-properties, 4, 708 Benzo[b]furan, 2-lithio-synthesis, 4, 652 Benzo[i]furan, 3-lithio-ring opening, 4, 79 Benzo[b]furan, methoxy-mass spectrometry, 4, 583 Benzo[b]furan, 6-methoxy-2,3-diphenyl-synthesis, 4, 679... 

Hsynthesis from, 3, 767 Indenobenzazepines pharmacological properties, 7, 546 Indenone oxide, 2,3-diphenyl-photochromic compound, 1, 385 In deno[ 1,2-c][ 1,2,4]triazines synthesis, 3, 434 Indicated hydrogen nomenclature, 1, 33 Indigo, I, 317, 318-319, 4, 370 Baeyer synthesis, 1, 319 colour and constitution, 1, 344-345 molecular structure, 4, 162 photochromic compound, 1, 386 synthesis, 4, 247 Indigoid dyes... 

Lumazine, 6,7-diphenyl-5,6-dihydro-properties, 3, 306 UV spectrum, 3, 279 Lumazine, 6,7-diphenyl-2-thio-glycosidation, 3, 297 reactions, 3, 300 Lumazine, 6,7-diphenyl-4-thio-reactions, 3, 300 Lumazine, 2,4-dithio-methylation, 3, 299 Lumazine, l-/3-D-glucopyranosyl-NMR, 3, 282 Lumazine, 1-hydroxy-structure, 3, 282... 

Pteridine, 2,4-diamino-6,7-diisopropyl-pharmacological properties, 3, 325 Pteridine, 2,4-diamino-6,7-dimethyl-pharmacological properties, 3, 325 Pteridine, 2,4-diamino-2,6-diphenyl-... 

The effect of structural variations in siloxane oligomers in the synthesis and properties of the resulting siloxane-urea copolymers have also been investigated 161). In these studies aminopropyl-terminated poly(dimethyl-diphenyl)siloxane and poly-... 

Fig. 16.6 The 1,3-diphenyl propane skeleton of flavonoids and the numbering system for flavonoids. Three structural features optimise the radical scavenging properties of a flavonoid (i) an orto-dihydroxy structure of the B-ring (catechol) (ii) 2,3 double bond in conjugation with a 4-oxo group (iii) 3- and 5-hydroxy groups (Bors and Saran, 1987).

Chan, C.-W., Wong, W.-T. and Che, C.-M. (1994) Gold(lll) photooxidants. Photophysical, photochemical properties, and crystal structure of a luminescent cyclometallated gold(lll) complex of 2,9-diphenyl- 1,10-phenanthroline. Inorganic Chemistry, 33, 1266-1272. 

Purely aromatic ethers e.g., diphenyl ether), which are commonly encountered, are very limited in number. Most of the aromatic ethers are of the mixed aliphatic - aromatic type. They are not attacked by sodium nor by dilute acids or alkalis. When liquid, the physical properties (b.p., and n ) are useful constants to assist in their identification. Three important procedures are available for the characterisation of aromatic ethers. 

Ethers are unaffected by sodium and by acetyl (or benzoyl) chloride. Both the purely aliphatic ethers e.g., di-n-butyl ether (C4H, )30 and the mixed aliphatic - aromatic ethers (e.g., anisole C3HSOCH3) are encountered in Solubility Group V the purely aromatic ethers e.g., diphenyl ether (C,Hj)20 are generally insoluble in concentrated sulphuric acid and are found in Solubility Group VI. The purely aliphatic ethers are very inert and their final identification may, of necessity, depend upon their physical properties (b.p., density and/or refractive index). Ethers do, however, suffer fission when heated with excess of 67 per cent, hydriodic acid, but the reaction is generally only of value for the characterisation of symmetrical ethers (R = R ) ... 

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