Improvements in the Manufacture of Anthranilic Acid.
Year: 1899

page_text: i
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Anthranilic Acid.
I, BENJAMIN WILLCOX, of 47, Lincoln's Inn Fields, in the County of London,
Patent Agent, do hereby declare the nature of this invention (which has been
communicated to me from abroad by the Badische Anilin & Soda Fabrik, of
Ludwigshafen-on-Rhine, in the German Empire) to be as follows:
My foreign correspondents have discovered that if ortho-nitro-toluol be suit-
ably treated with an alkali, or alkaline earth, it is converted into anthranilic
acid, or into intermediate products readily convertible thereinto the oxygen bound
to the nitrogen, or the affinity of the nitrogen for hydrogen, or both, effecting
or promoting the oxidation of the methyl-group under the influence of the alkali
o alkaline earth.
If a very concentrated alkaline solution, or a solid alkali, be used, or if the
temperature rise too high, the reaction with ortho-nitro-toluol is liable to pro-
ceed too vigorously, and decomposition, and a considerable formation of bye-
products, take place. My foreign correspondents have found that, when pro-
ceeding under certain conditions, azoxy-benzoic acid, or similar intermediate
products, sometimes form, and these can be readily converted into anthranilic
acid by means of reducing agents, such as ammonium sulphide.
The following examples will serve to further illustrate the nature of the
invention, which however is not confined to the methods of operating, or the
proportions, and temperatures, set out in these examples. The parts are by
weight.
EXAMPLE 1.
PRODUCTION OF ANTHRANILIC ACID FROM ORTHO-NITRO-TOLUOL BY TREATMENT
WITH AQUEOUS ALKALI.
Heat to a temperature of about 150° Centrigrade about one hundred parts of
caustic soda lye (containing about 35 per cent real NaOH) in a closed vessel pro-
vided with a stirrer and safety-valve. Then add, gradually and whilst stirring,
and maintaining the same temperature, one hundred parts of ortho-nitro-toluol.
Maintain the temperature, whilst continually stirring, until an examination of
test portions shews that the greater part of the nitro-toluol has disappeared.
This usually takes place in about twelve hours. Then distil off the remainder
of the oil by means of steam and separate, in any known, or suitable way, the
anthranilic from the aqueous solution remaining.
EXAMPLE 2.

page_text: Heat this mixture, until it boils, in a vessel provided with an inverted condenser,
and maintain the boiling until the odour of the ortho-nitro-toluol has practically
disappeared. Saturate the reaction product with ammonia, and sulphuretted
hydrogen, and then boil again for several hours in order to complete the reduction
to anthranilic acid. Next evaporate to dryness to drive off the excess of am-
monium sulphide and alcohol. Treat the reaction product with water, filter, if
necessary, acidify with acetic acid, and precipitate the anthranilic acid by means
of copper sulphate. Isolate and purify the acid in any known or suitable way.
Dated this 11th day of September 1899.
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, London, W.C., Agents.
Improvements in the Manufacture of Anthranilic Acid.
I, BENJAMIN WILLCOX, of 47, Lincoln's Inn Fields, in the County of London,
Patent Agent, do hereby declare the nature of this invention (which has been
communicated to me from abroad by the Badische Anilin & Soda Fabrik, of
Ludwigshafen-on-Rhine, in the German Empire) and in what manner the same
is to be performed, to be particularly described and ascertained in and by the
following statement:
My foreign correspondents have discovered that if ortho-nitro-toluol be suit-
ably treated with an alkali, or alkaline earth, it is converted into anthranilic
acid or into intermediate products readily convertible thereinto the oxygen bound
to the nitrogen, or the affinity of the nitrogen for hydrogen, or both, effecting,
or promoting the oxidation of the methyl-group under the influence of the alkali
or alkaline earth.
If a very concentrated alkaline solution, or a solid alkali, be used, or if the
temperature rise too high, the reaction with ortho-nitro-toluol is liable to pro-
ceed too vigorously, and decomposition, and a considerable formation of bye-
products, take place. My foreign correspondents have found that, when pro-
ceeding under certain conditions, azoxy-benzoic acid, or similar intermediate
products, sometimes form, and these can be readily converted into anthranilic
acid by means of reducing agents, such as ammonium sulphide.
The following examples will serve to further illustrate the nature of the in-
vention and the manner in which it can be performed, it is however not confined
to the methods of operating, or the proportions and temperatures, set out in these
examples. The parts are by weight.
EXAMPLE 1.
PRODUCTION OF ANTHRANILIC ACID FROM ORTHO-NITRO-TOLUOL BY TREATMENT
WITH AQUEOUS ALKALI.
Heat, to a temperature of about one hundred and fifty degrees Centigrade,
about one hundred parts of caustic soda lye, (containing about 35 per cent real
NaOH), in a closed vessel provided with a stirrer and safety valve. Then add,
gradually, and whilst stirring, and maintaining the same temperature, one hundred
parts of ortho-nitro-toluol. Maintain the temperature, whilst continually stirring,
until an examination of test portions shews that the greater part of the nitro-
toluol has disappeared. This usually takes place in about twelve hours. Then
distil off the remainder of the oil by means of steam and separate, in any known,
or suitable, way, the anthranilic acid from the aqueous solution remaining.

page_text: PRODUCTION OF ANTHRANILIC ACID FROM ORTHO-NITRO-TOLUOL BY TREATMENT
WITH AN ALCOHOLIC ALKALI.
Mix together one hundred and thirty seven parts of ortho-nitro-toluol, one
hundred and twenty parts of caustic soda, and five hundred parts of alcohol.
Heat this mixture, until it boils, in a vessel provided with an inverted condenser,
and maintain the boiling until the odour of the ortho-nitro-toluol has practically
disappeared. Saturate the reaction product with ammonia, and sulphuretted
hydrogen, and then boil again for several hours, in order to complete the reduction
to anthranilic acid. Next evaporate to dryness, to drive off the excess of am-
monium sulphide and alcohol. Treat the reaction product with water, filter, if
necessary, acidify with acetic acid, and precipitate the anthranilic acid by means
of copper sulphate. Isolate and purify the acid in any known, or suitable, way.
Having now particularly described and ascertained the nature of this in-
vention and in what manner the same is to be performed I declare that what
I claim is:-
1. The manufacture of anthranilic acid from ortho-nitro-toluol by treatment
with an alkali, or alkaline earth, substantially as herein before described.
2. The manufacture of anthranilic acid from ortho-nitro-toluol by treating it
with an alkali and subsequently reducing the intermediate products that may be
obtained with a reducing agent, substantially as hereinbefore described.
3. The manufacture of anthranilic acid from ortho-nitro-toluol in the manners
described in the foregoing examples.
Dated this 2nd day of Juna 1000
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, London, W.C., Agents.