The original article for the translation above can bee found at:
https://www.thevespiary.org/rhodium/Rhodium/djvu/aniline.demethylation.djvu (https://www.thevespiary.org/rhodium/Rhodium/djvu/aniline.demethylation.djvu)
(https://www.thevespiary.org/rhodium/Rhodium/djvu/aniline.demethylation.djvu)
Anilines are unfortunately not OTC (as far as Lego knows).
This article was found by Lego some time ago when investigating the potential of the Lossen degradation.
Journal of the American Chemical Society, 1953, 75, 2014-2015
Conversion of Aromatic Acids and their Derivatives to Amines
[...]
General Method: To 25-50 g of polyphosporic acid was added the carboxylic acid and slightly more than the theoretical amount of hydroxylamine sulfate or hydrochloride. The mixture was stirred mechanically and heated slowly on an oil-bath. When the chloride salt was hydrogen chlorie was evolved from the reaction mixture as the temperature approached 100°. Upon further increase in temperature the reactants gradually entered solution. In the range 150-170° there was a rapid evolution of carbon dioxide and the mixture darkened considerably. When the frothing has ceased the mixture was poured onto crushed ice. The insoluble material was removed and the filtrate was neutralized with potassium hydroxide. The liberated amine, if liquid, was extracted with several portions of benzene. The combined extracts were dried over sodium hydroxide pellets and then treated with dry hydrogen chloride gas. The precipitated hydrochloride was collected and dried in a desiccator. If the amine was solid it was filtered from the basic solution directly and then dried. The yield of the crude amines obtained in this way are reported in Table I.
beta-Naphtylamine: To a mixutre of 1.7 g (0.24 mole) of hydroxylamine hydrochloride and 4.0 g (0.23 mole) of -naphtoic acid was added 50 g. of polyphosphoric acid. The mixture was stirred mechanically and the temperature was gradually raised. At 160°C the evolution of carbon dioxide had ceased and the brown mixture was poured over 250 g. of crushed ice. Filtration of the resulting mixture yielded 0.7 g. of an orange colored solid, which displayed no definitite melting point. The filtrate was neutralized with potassium hydroxide and the precipitated amine was collected and dried. The yield was 2.7 g (82%) of light tan beta-naphtylamine, m.p. 107-109° (lit. 111-112°).
Aniline from benzophenone: To a mixture of 2.1 g. (0.030 mole) of hydroxylamine hydrochloride dissolved in 20 g. of polyphosphoric acid was added 1.82 g. (0.010 mole) of benzophenone. The mixture was heated with constant stirring to 160-165° for ten minutes. The purple mixture was poured over 100 g. of crushed ice and the small amount of insoluble material was removed by filtration. The filtrate was made strongly basic with potassium hydroxide and then extracted thoroughly with benzene. The extracts were dried over sodium hydroxide and then saturated with dry hydrogen chloride. The precipitated aniline hydrochloride was collected and dried in a desiccator. The dry hydrochloride hat a light purple tinge and melted 188-191°. The yield was 1.72 g. (66%).
Table I:
Reactant | Isolated or expected product | Yield | M.p., °C. | Reported m.p., °C |
alpha-Naphtoic acid | alpha-Naphtylamine | 82 | 107-109 | 111-112 |
beta-Naphtoic acid | beta-Naphtylamine | 80 | 43-45 | 50 |
Benzoic acid | aniniline hydrochloride | 66 | 190-192 | 198 |
m-Toluic acid | m-toluidine hydrochloride | 76 | 223-225 | 228 |
p-Toluic acid | p-toluidine hydrochloride | 72 | 238-239 | 243 |
o-Bromobezoic acid | o-Bromoaniline hydrochloride | 53a | | |
m-Bromobezoic acid | m-Bromoaniline hydrochloride | 46a | | |
p-Bromobezoic acid | p-Bromoaniline hydrochloride | 43a | | |
p-Chlorobenzoic acid | p-Chloroaniline | 32 | 69-70 | 70-71 |
Salicyl acid | Benzoxazolone | 33b | 137-138 | 138 |
o-Phenylbenzoic acid | Phenanthridone | 40 | 292 | 293 |
m-Nitrobenzoic acid | m-Nitroaniline | 53 | 109-110 | 112 |
o-Nitrobenzoic acid | o-Nitroaniline | 0 | | |
p-Nitrobenzoic acid | p-Nitroaniline | 0 | | |
Valeric acid | n-Butylamine | 0 | | |
Caprylic acid | n-Heptylamine | 0 | | |
Ethyl benzoate | Aniniline hydrochloride | 68 | 190-193 | 198 |
Benzamide | Aniniline hydrochloride | 43 | 190-193 | 198 |
Benzoyl chloride | Aniniline hydrochloride | 51 | 189-192 | 198 |
Benzonitrile | Aniniline hydrochloride | 20 | 190-192 | 198 |
p-Chlorobenzamide | p-Chloroaniline | 0 | | |
Benzanilide | Aniline hydrochloride | 76 | 188-191 | 198 |
p,p'-Dichlorobenzanilide | p-Chloroaniline | 48 | 66-70 | 70-71 |
p,p'-Dichlorobenzophenone oxime | p-Chloroaniline | 40 | 65-68 | 70-71 |
p,p'-Dichlorobenzophenone | p-Chloroaniline | 15 | 69-70 | 70-71 |
Benzophenone | Aniline hydrochloride | 66 | 188-191 | 198 |
N-Methyl-p-chlorobenzamide | p-Chloroaniline, methylamine | 0 | | |
N-Methylbenzamide | Aniline, methylamine | 0 | | |
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(a) Identity confirmed by conversion to acetyl derivative
(b) Recrystallized once from water
Comment by Lego: The depressed melting points indicate impure product but in this case this should bee no trouble as the aniline is used in excess.
Preparation of polyphosphoric acid:
Post 398338 (https://www.thevespiary.org/talk/index.php?topic=9688.msg39833800#msg39833800)
(Aurelius: "repost", Methods Discourse)