Showing papers on "Fluorenone published in 1971"

The photosensitised decarboxylation of carboxylic acids by aromatic ketones

Abstract: Xanthone, fluorenone, 2-acetylnaphthalene, and acetophenone have been found to photosensitise the decarboxylation of acids of the type RX·CH2·CO2H (where X = O, S, or NH). Substituted hydrocarbons (RX·CH3) are formed in the reactions, and their yields are substantialy increased by the inclusion of benzenethiol in the reaction mixture.

Thiophene analogues of fluorenone: Cleavage reactions

Abstract: The cleavage reactions of non-enolizable thienyl ketones have been studied. Potassium t-butoxide in t-butanol, ether or dioxane has proved to be a mild cleavage reagent. With most ketones high yields of acids were obtained after a short reaction time at room-temperature. Possible mechanisms for these mild reactions and the Haller-Bauer cleavage of thienyl ketones are discussed.

The photosensitised oxidation of amines. Part III. The use of xanthone, fluorenone, p-aminobenzophenone, and methyl β-naphthyl ketone as sensitisers

Abstract: Irradiation of oxygenated solutions of triethylamine, di-n-propylamine, and n-propylamine, containing xanthone, fluorenone, p-aminobenzophenone, and methyl β-naphthyl ketone, results in the amines being oxidised. The reactions are interpreted as occurring by initial hydrogen abstraction from the amine by the excited ketone, to give radicals of the amines which subsequently react with oxygen to give the observed products.

Quenching of Fluorenone Triplet by Amines

Abstract: フルオレノンの三重項状態のアミン類による失活過程についての直接的な知見を得るために閃光法により, n-ヘキサン溶液中で研究した。アミン類を含まないフルオレノン溶液に閃光を照射して得られる中間体の吸収は,フルオレノン三重項によるものと結論された。つぎにアミン類を加えた溶液では三重項の減衰が速く,アミン類による三重項の失活が確認された。その減衰速度のアミン類濃度への依存性から失活速度定数kqが求められた。この値は107～109l・mol-1・sec-1程度で,とくに芳香族アミンに関するそれは拡散律速に近い。一方, n-ブチルアミンは失活に効果的でない。また,これらの結果から,アミンのイオン化電位が低くなるにしたがい, kqが大きくなることが明らかにされた。これはアミン類によるフルオレノンー重項の失活に関してすでに知られている傾向と一致する。さらに失活速度定数と光還元反応の量子収率との比較から反応機構について論ずる。