- Sulfonation of arylamines: Part 11 - Preparation and thermal decomposition of ring-substituted arylammonium hydrogen sulfates
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Eight ring-substituted arylammonium hydrogen sulfates (RSAHS) have been prepared by reacting corresponding arylamine with excess of conc. H2SO4. Their thermal decomposition has been investigated by TG and DSC techniques. The decomposition pathways have also been suggested.
- Singh,Kapoor,Singh
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p. 229 - 232
(2007/10/03)
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- Sulfonation of arylamines : Part VII-Kinetics of thermal decomposition of tetramethyldianilinium sulfates
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Tetramethyldianilinium sulfates (TMDAS) have been prepared and characterised. Thermal decomposition of these salts has been studied by TO and kinetics evaluated using Prout-Tompkins equation. Activation energies of these salts are found to be linearly related to the pKa of the corresponding amine. It has been found that TMDAS give dimethylaminobenzenesulfonic acids (DMAB-SA) via solid state reaction induced by heat. A reaction scheme representing the thermal decomposition pathways of these salts has been suggested. The proton transfer (unimolecular elementary reaction) seems to be the primary step which is followed by a bimolecular step (sulfonalion) for the decomposition of these salts.
- Singh, Gurdip,Kapoor, Inder Pal Singh,Singh, Jyotsna
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p. 590 - 595
(2007/10/03)
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- Studies of Reactions of Amines with Sulfur Trioxide. VI. Thermal Reactions of Anilinium, Dimethylanilinium, and Trimethylanilinium Salts of Butylamidosulfuric Acid
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When the title compounds were heated in an evacuated reaction vessel, both transsulfonation and rearrangement occurred.At lower temperatures (80-120 deg C) the corresponding phenylamidosulfates and sulfophenylamidosulfates (transsulfonation products) were the main products.Increasing temperature led to the formation of ring mono- and disulfonates (rearrangement products) at the expense of the transsulfonation products.The sulfonate group always migrated to the ortho and/or para position(s) to the amino group.In no case was any meta-product detected.There was no significant difference in the ease of transsulfonation among the anilinium salts studied exept 2,6-dimethyl- and 2,4,6-trimethylanilinium salts.On the other hand, the ease of rearrangement and the orientation of ring sulfonation depended strongly on the structure of the substrate anilines.The thermal reactions of 2,4,6-trimethylanilinium butylamidosulfate produced (2,4,6-trimethylphenylimido)bis(sulfate) in addition to (2,4,6-trimethylphenylamido)sulfate.This is the first isolation of an arylimidobis(sulfate) from such reactions.Mechanisms of the transsulfonation and rearrangement have been discussed.
- Kanetani, Fujio,Yamaguchi, Hachiro
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p. 3048 - 3058
(2007/10/02)
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- Zur Synthese sulfonierter Derivate von 2,3-Dimethylanilin und 3,4-Dimethylanilin
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Baking the hydrogensulfate salt of 2,3-dimethylaniline (1) or of 3,4-dimethylaniline (2) led to 4-amino-2,3-dimethylbenzenesulfonic acid (4) and 2-amino-4,5-dimethylbenzenesulfonic acid (5), respectively (Scheme 1).The sulfonic acid 5 was also obtained by treatment of 2 with sulfuric acid or by reaction of 2 with amido-sulfuric acid. 3-Amino-4,5-dimethylbenzenesulfonic acid (3) and 5-amino-2,3-dimethylbenzenesulfonic acid (6) were prepared by sulfonation of 1,2-dimethyl-3-nitrobenzene (9) to 3,4-dimethyl-5-nitrobenzenesulfonic acid (11) and of 1,2-dimethyl-4-nitrobenzene (10) to 2,3-dimethyl-5-nitrobenzenesulfonic acid (12), respectively, with subsequent Bechamp reduction (Scheme 1).Preparations of 2-amino-3,4-dimethylbenzenesulfonic acid (7) and of 6-amino-2,3-dimethylbenzenesulfonic acid (8) were achieved by the sulfur dioxide treatment of the diazonium chlorides derived from 3,4-dimethyl-2-nitroaniline (24) and from 2,3-dimethyl-6-nitroaniline (31) to 3,4-dimethyl-2-nitrobenzenesulfonyl chloride (29) and 2,3-dimethyl-6-nitrobenzenesulfonyl chloride (32), respectively, followed by hydrolysis to 3,4-dimethyl-2-nitrobenzenesulfonic acid (30) and 2,3-dimethyl-6-nitrobenzenesulfonic acid (33), and final reduction (Scheme 3).Compound 7 was also synthesized by reaction of 4-chloro-2,3-dimethylaniline (23) with amidosulfuric acid to 2-amino-5-chloro-3,4-dimethylbenzenesulfonic acid (20) and subsequent hydrogenolysis (Scheme 2). 4'-Bromo-2',3'-dimethyl-acetanilide (13) and 4'-chloro-2',3'-dimethyl-acetanilide (14) on treatment with oleum yielded 5-acetylamino-2-bromo-3,4-dimethylbenzenesulfonic acid (17) and 5-acetylamino-2-chloro-3,4-dimethylbenzenesulfonic acid (18), respectively.Their structures were proven by hydrolysis to 5-amino-2-bromo-3,4-dimethylbenzenesulfonic acid (21) and 5-amino-2-chloro-3,4-dimethylbenzenesulfonic acid (22), followed by reductive dehalogenation to 3.Reaction of 1 with sulfuric acid gave a mixture of 3,4 and 7, whereas sulfonation of 2',3'-dimethyl-acetanilide with subsequent hydrolysis led to a mixture of 3 and 4.Treatment of 3',4'-dimethyl-acetanilide with oleum followed by hydrolysis resulted in the formation of mainly 5 and a small amount of unknown product.
- Courtin, Alfred,Tobel, Hans-Rudolf von
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p. 385 - 394
(2007/10/02)
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