- Carbon-carbon cleavage of aryl diamines and quinone formation using sodium periodate: a novel application
-
A first novel synthetic utility of sodium periodate for aryl diamine carbon-carbon cleavage is described. Aryl 1,2-diamine compounds were successfully converted into corresponding nitriles, while the developed method is also useful for the preparation of quinones from corresponding aryl 1,4-diamine compounds. The advantages of this protocol are shorter reaction time and mild reaction conditions to obtain moderate to good yields.
- Telvekar, Vikas N.,Takale, Balaram S.
-
experimental part
p. 3940 - 3943
(2010/08/07)
-
- Process for producing α-anthraquinonesulfonic acids and recovering the catalyst used therein
-
The present invention concern a process for producing α-anthraquinonesulfonic acids in the presence of a metal catalyst in oleum and recovering the metal catalyst which is solubilized in the resulting sulfonation mixture. A porous carrier is introduced into the resulting sulfonation mixture which is subsequently treated with a reducing agent thereby depositing the metal catalyst on the porous carrier.
- -
-
-
- Equilibrium and Kinetic Studies of Some Reactions of 1-Anthraquinonesulfenic Acid and Its Methyl Ester
-
1-Anthraquinonesulfenic acid (2) is a stable arenesulfenic acid.Its pKa, and the products and kinetics of its reactions, and those of its methyl ester (3), with both a thiol (n-BuSH) and m-chloroperoxybenzoic acid (MCPBA), have been determined.The results are compared with those for the corresponding reactions of two stable areneselenic acids (1a and 1b).The pKa of 2 (7.51) shows it to be ca. 3 pK units stronger acid than o-O2NC6H4SeOH (1a).Reaction of 2 and 3 with n-BuSH occurs at comparable rates and gives n-butyl 1-antraquinonyl disulfide (5) via a reactionthat is acid catalyzed.The rate of reaction of 2 with the thiol is ca. 104 slower than the rate of reaction of the structurally analogous areneselenenic acid, o-PhC(O)C6H4SeOH (1b).The probable reason for this large difference in rates is outlined.The difference in the rates of oxidation of 2 and 1b by MCPBA is much smaller, the selenenic acid being oxidized only 6 times faster than 2.Just as was found with selenenic acid 1a and its methyl ester, the rate of oxidation of sulfenic acid 2 by MCPBA is much faster than the rate of oxidation of its methyl ester.
- Kice, John L.,Weclas-Henderson, Ludmilla,Kewan, Aly
-
p. 4198 - 4203
(2007/10/02)
-
- Process for producing anthraquinone-1-sulphonic acid by sulphonation with palladium catalyst
-
A process for the production of anthraquinone-1-sulphonic acid by sulphonating anthraquinone with a sulphonating agent in the presence of palladium catalyst in a solvent, is characterized in that before sulphonation, the palladium is mixed with nitric acid or mineral acids containing nitric acid at room temperature and then the acid is removed from the treated palladium. Preferably, the sulphonating agent of 1-10% SO3 is first mixed with the nitric acid treated palladium as a solvent, and the same sulphonating agent of 50-65% SO3 is added for sulphonation at about 90-100 degs. C.
- -
-
-
- Process for concentrating halogenoanthraquinones
-
A process for concentrating at least one of (a) individual halogenoanthraquinones (b) binary mixtures of di-halogenoanthraquinones and (c) binary mixtures of trihalogenoanthraquinones, from a mixture containing at least two halogenoanthraquinones, comprising subjecting said mixture containing at least two halogenoanthraquinones to fractional vacuum distillation in a heated rectification column having an efficiency corresponding to about 20 to 50 theoretical stages with an absolute pressure at the top of about 0.5 to 50 mm Hg and a reflux to take-off ratio of about 5/1 to 50/1. Advantageously, distillation is carried out continuously in a cascade of columns, the products withdrawn from the top of the first column being 2-chloroanthraquinone in the first stage, 1-chloroanthraquinone in the second stage, 1,6- and 1,7-dichloroanthraquinone in the third stage and 1,5- and 1,8-dichloroanthraquinone in the fourth stage, 1,4,5- and 1,4,6-trichloroanthraquinone being obtained in the sump of the 4th stage and being separated therefrom by film evaporation. The mixture of halogenoanthraquinones is advantageously a mixture of chloroanthraquinones such as is obtained by the action of chlorine, chloric acid or a chlorate on various industrial mixtures of nitro- or sulfo-anthraquinones.
- -
-
-
- Sulfonation of anthraquinone in sulfur dioxide solvent
-
Sulfonation of anthraquinone by a sulfur trioxide component including SO3 or oleum in a liquid sulfur dioxide solvent. When a mercury catalyst is used to give alpha anthraquinone sulfonate products, most of the mercury is left in the reactor or recovered with unreacted anthraquinone by precipitation with water after vaporization of the sulfur dioxide. High sulfuric acid and mercury pollution are thus avoided.
- -
-
-
