Improvements in the Manufacture and Production of Acetyl- Anthranilic Acid.
Year: 1897

page_text: Date of Application, 11th Mar., 1897
Complete Specification Left, 13th Dec., 1897-Accepted, 15th Jan.,
1898
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture and Production of Acetyl-
Anthranilic Acid.
I, JAMES YATE JOHNSON, of 47, Lincoln's Inn Fields, in the County of London,
Gentleman, do hereby declare the nature of this Invention (which has been com-
municated to me from abroad by the Badische Anilin & Soda Fabrik of Lud-
wigshafen-on-Rhine, in the Empire of Germany), to be as follows:-
It is known that acetyl-anthranilic acid can be produced by oxidizing acetyl-
ortho-toluidine with potassium permanganate in weak acetic acid solution; but
the yield obtained thereby has only been a little above thirty per cent. of the
theoretical. No better results have been obtained by oxidizing the acetyl-toluidine
in mineral acid, or alkaline, solution.
My foreign correspondents have discovered that this oxidation can be very
successfully done by adding an inorganic sult to the oxidation liquor. Although
this salt is neutral, it is still able to continuously remove the alkali yielded by
the reaction. As such a salt, magnesuim sulphate is eminently adapted for use.
It is converted by the alkali hydrate, formed when employing a permanganate,
into the alkali sulphate, and insoluble magnesuim oxide, which latter, by reason
of its insolubility, does not influence the reaction. In this way seventy-five to
eighty-five per cent. of the theoretical yield of acetyl-anthranilic acid is easily
obtained, and this can be converted into anthranilic acid in the ordinary way,
by treating with dilute alkali, or mineral acids.
The following example will serve to further illustrate the nature of the invention
but I do not limit myself to the precise details therein given. The parts are
by weight.
EXAMPLE.
Heat on the water bath about fifty parts of acetyl-ortho-toluidine, one hundred
and three parts of crystallized magnesium sulphate, and six thousand parts of
water, in an enamelled vessel furnished with a stirrer and a thermometer, at a
temperature of seventy-five to eighty degrees centigrade until a clear solution is
obtained. Then stir and add at once one hundred and forty six parts of
crystallised potassium permanganate. The temperature rises to eighty-five
degrees centigrade and is maintained at this point for one hour and a half until
the permanganate has completely disappeared. Filter the hot solution and
acidify the filtrate with dilute sulphuric acid. Filter off the acetyl-anthranilic
acid, which separates out as a colourless precipitate; wash with a little water,
and press, and dry at a temperature of about seventy degrees centigrade.
Dated this 11th day of March 1897.

page_text: Improvements in the Manufacture and Production of Acetyl-
Anthranilic Acid.
I, JAMES YATE JOHNSON, of 47, Lincoln's Inn Fields, in the County of London,
Gentleman, do hereby declare the nature of this invention (which has been com-
municated to me from abroad by the Badische Anilin-&-Sola-Fabrik of Lud-
wigshafen-on-Rhine, in the Empire of Germany), and in what manner the same
is to be performed, to be particularly described and ascertained in and by the
following statement:-
It is known that acetyl-anthranilic acid can be produced by oxidizing acetyl-
ortho-toluidine with potassium permanganate in weak acetic acid solution; but
the yield obtained thereby has only been a little above thirty per cent. of the
theoretical. No better results have been obtained by oxidizing the acetyl-toluidine
in mineral acid, or alkaline, solution.
for use.
My foreign correspondents have discovered that this oxidation can be very
successfully done by potassium permanganate in the presence of an inorganic
salt which, although neutral, is able to continuously remove the alkali yielded
during the reaction. As such a salt magnesium sulphate is eminently adapted
It is converted by the alkali-hydrate, formed when employing a per-
manganate, into the alkali-sulphate and insoluble magnesium hydroxide, which
latter, by reason of its insolubility, does not influence the reaction. In this way
seventy-five, to eighty-five, per cent. of the theoretical yield of acetyl-anthranilic
acid is easily obtained, and this can be converted into anthranilic acid in the
ordinary way, by treating with dilute alkali, or mineral acids.
The following example will serve to further illustrate the nature of the inven-
tion and the manner in which it can be performed but I do not limit myself to
the precise details therein given. The parts are by weight.
EXAMPLE.
About fifty parts of acetyl-ortho-toluidine, one hundred and three parts of
crystallized magnesiuni sulphate and six thousand parts of water, in an enamelled
vessel furnished with a stirrer and a thermometer, are heated on a water-bath, at
a temperature, of about seventy-five, to eighty, degrees centigrade, until a clear
solution is obtained. Then stir and add at once one hundred and forty-six parts
of crystallized potassium permanganate. The temperature rises to eighty-five
degrees centigrade and is maintained at this point for one hour and a half until
the permanganate has completely disappeared. Filter the hot solution and acidify
the filtrate with dilute sulphuric acid. Filter off the acetyl-anthranilic acid
which separates out as a colourless precipitate: wash with a little water and
press and dry at a temperature of about seventy degrees centigrade.
Having now particularly described and ascertained the nature of this
invention and in what manner the same is to be performed I declare that what I
claim is:-
1. The manufacture or production of acetyl-anthranilic acid by oxidising
acetyl-ortho-toluidine in aqueous solution with potassium permanganate in the
presence of an inorganic salt, which, although neutral, is able to continuously
remove the alkali yielded during the reaction.
2. The manufacture or production of acetyl-anthranilic acid by oxidising acetyl-
ortho-toluidine in aqueous solution with potassium permanganate in the presence
of magnesium sulphate, substantially as hereinbefore described.

page_text: 3. The manufacture of acetyl-anthranilic acid substantially in the manner
herein before described in the example.
Dated this 13th day of December 1807
JOHNSONS & WILLCOX,
47 Lincoln's Inn Fields, London, W.C., Agents.