Paraquinones sentence example

paraquinones
  • These three compounds are perhaps to be represented as orthoor as paraquinones (see papers by F.
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  • QUINONES, in organic chemistry, a group of compounds in which two hydrogen atoms of a benzene nucleus are replaced by two oxygen atoms. This replacement may take place either in the ortho or para positions, giving rise to orthoquinones or to paraquinones; metaquinones do not appear to have been isolated.
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  • Pechmann (Ber., 1888, 21, p. 1417) has shown that a-diketones are converted into paraquinones by the action of warm solutions of the caustic alkalis, diacetyl yielding para-xyloquinone: CH 3 CO CO CH 3 CH 3 C CO.
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  • soc. chim., 18 94 (3) 11, p. 1129) obtained anilino-derivatives of the paraquinones by the action of an aqueous solution of potassium chromate on an acetic acid solution of para-aminodimethylaniline and phenol: C 6 H 5 OH+H 2 N C 6 H 4 N (CH 3) 2 - *O:C 6 H 4 :N C 6 H 4 N(CH 3) 2; these compounds yield the quinone when heated with mineral acids.
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  • The paraquinones are generally crystalline solids of a yellowish colour, having a characteristic sharp odour and being volatile in steam.
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  • Paraquinones also combine with ammonia and with amines yielding amino-derivatives and hydroquinones.
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  • The orthoquinones more resemble the a-diketones; they are crystalline solids of a red or yellow colour, but differ from the paraquinones in being devoid of smell and not volatile in a current of steam.
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