Anthraquinone from styrene

When an anion-radical initiator bears chemically active groups, it is incorporated into the polymer chain. Eor instance, the polymer obtained from styrene under initiation by 9,10-anthraquinone anion-radical, that is, anthrasemiquinone, contains oxyanthracenyl (ethereal) fragments (Karpinets 2004). It is seemingly suitable to introduce functional groups into macromolecules through this way. 

Photo-induced H-abstraction of anthraquinone from xanthene has been studied using nuclear polarization-detected EPR and the structure of the resulting short-lived radical pair determined.194 The retrodisproportionation reactions of a variety of styrenes with 9,10-diliydroanthracene (DHA), xanthene (XAN), and 9,10-dihydroacridine (DHAc) have been studied in order to determine if there was any evidence of the alternative hydride-transfer mechanism in competition with the proposed H-atom-transfer mechanism. No such evidence was found.195 The reaction between azulene and DHAC... 

The performance of many metal-ion catalysts can be enhanced by doping with cesium compounds. This is a result both of the low ionization potential of cesium and its abiUty to stabilize high oxidation states of transition-metal oxo anions (50). Catalyst doping is one of the principal commercial uses of cesium. Cesium is a more powerflil oxidant than potassium, which it can replace. The amount of replacement is often a matter of economic benefit. Cesium-doped catalysts are used for the production of styrene monomer from ethyl benzene at metal oxide contacts or from toluene and methanol as Cs-exchanged zeofltes ethylene oxide ammonoxidation, acrolein (methacrolein) acryflc acid (methacrylic acid) methyl methacrylate monomer methanol phthahc anhydride anthraquinone various olefins chlorinations in low pressure ammonia synthesis and in the conversion of SO2 to SO in sulfuric acid production. 

Photosensitized crosslinking of polymers has been the subject of numerous publications [l - 30], concerned mainly with poly(ethylene), poly(vinyl alcohol), various vinyl copolymers, copolymers of maleic anhydride and/or phtalic anhydride with styrene and some polymers derivated from cinnamic acid. The following compounds were used as sensitizers benzophenone, 4-chloro- and 4,4-dimethylbenzophenone [l, 3-6, 8, 9l, oC -and -derivatives of anthraquinone [3, 23] acetophenone, hydroquinone, triphenylmethane and pyridine li.] chlorobenzene and no less than trichlorinated n-paraffins [6], a complex of zink chloride with o-dia-nizidine fill potassium bichromate [l2j, anthracene fl3, 14] 2,5-methoxy-4-amino-trans-stilbene [l5], benzyl ideneacetophenone fl6-l8] -thiophenylacetophenone,... 

Bezuglyi and co-workers have published information on the reactivity of anion radicals and dianions of some a- substituted 9,10-anthraquinones generated electrochemically. The ions from the substituted anthraquinones will polymerize styrene whereas methyl methacrylate will polymerize only in the presence of ions from the unsubstituted anthraquinone. This idea has been used by Miertus et al. for the polymerization of acrylonitrile initiated by electrolytically prepared radical anions of benzephenone and 2,2 -bipyridyl. Funt and Hsu have extended this... 

Styrene derivatives are commonly used addends in the photocycloaddition studies of 1,4-quinones. With Z- and -anethole, 1,4-benzoquinone (BQ), 1,4-naphthoquinone (NQ), and 9,10-anthraquinone in acetonitrile solvent yield spiro-oxetanes in which the trans-isomer (e.g., 4 from naphthoquinone) predominates. The process has been studied in detail by CIDNP techniques from which it is deduced that product formation proceeds from triplet radical ion pairs to the triplet biradical, and that there is no significant contribution from direct conversion of exciplex intermediates into the biradicals. Spiro-oxetane formation between simple alkenes and BQ generally has low regioselectivity but this is markedly improved with alkylidene cyclohexanes (Figure 87.3) such that the major isomer can be used as a new access to useful synthetic building blocks. For the BQ/homobenzvalene 5 system, however, where the difference in stability between the intermediate biradicals can be expected to be considerably less, the selectivity ratio for the spiro-oxetanes 6 and 7 is reduced to 3 1, respectively, and the addition to NQ yields only the cyclobutane derivative 8. Quadricyclane and norbornadiene undergo the same photocycloaddition reaction to BQ, affording the oxolane 9 and the spiro-oxetane 10. Evidence from CIDNP... 

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