Process for the Production of Anthranilic Acid.
Year: 1890

page_text: Date of Application, 12th Nov., 1890
Complete Specification Left, 20th July, 1891-Accepted. 22nd Aug. 1891
PROVISIONAL SPECIFICATION.
[Communicated from abroad by AMSTERDAMSCHE CHININEFABRIK, of Amsterdam,
Holland.]
Process for the Production of Anthranilic Acid.
I, OLIVER IMRAY, of No. 28 Southampton Buildings Chancery Lane, in the
County of London, Fellow of the Institute of Patent Agents, do hereby declare
the nature of this invention to be as follows:
The researches of A. W. Hofmann concerning the reaction of bromine and
alkalies upon amides (Ber. d. Deutch. Chem. Ges. XIV 2725, XV 407 752 762)
shewed that the acid amides are converted into amines under evolution of carbonic
acid. S. Hoogewerff and W. A. van Dorp found later that the amines are also
formed from the acid amides by hyperbromite of potash (Recueil d. Trav. Chim. d.
pays Bas. V 252. VI 373 VIII 173); they also demonstrate a quite similar
conversion of acid amides. Thus they converted succinimide by the reaction of
hyperbromite of potash, into B-amido-propionic acid (Verslagenen Mededeelingen
der Koninkl. Akad. v Vetensch. Afd. Naturir kunde III Reeks Deel VII p. 216).
An analogous process forms the basis of the present invention for the production
of anthranilic acid, in which my correspondents start from phtalimide.
Anthranilic acid is formed when 1 molecule of phtalimide is mixed with
1 molecule of an hyperchlorite or an hyperbromite (we employ the potassium,
sodium, calcium, barium, strotium, and magnesium salts) in the presence of fixed
alkalies or of alkaline earths (KOH, Na OLI, Ca (OH), Ba (OH), St (OH),) and
water, the mixture being heated. Anthranilic acid is also formed when, by the
introduction of chlorine or of bromine into the alkaline phtalimide solution, a
hypochlorite or a hypobromite is produced therein, and the mass is then heated.
Also, according to the method originally proposed by Hofmann for amides of the
nonocarbon acids, phtalimide (1 molecule) may be treated with 1 molecule of
promine, then excess of alkali be slowly added, and lastly the mass be heated.
All these modifications may be led back to a reaction which, when using hydrate
of soda and hydrochlorite of soda is represented by the following formula:
Instead of the sodium combinations the corresponding potassium combinations or
those of the alkaline earths may be used, and instead of the hypochlorite may be
taken a hyperbromite. But in order to produce a good yield, care must be taken
that in proportion to phtalamide-the hypochlorite or hypobromite are used in
exactly the proportions determined by the equation, and that at least so much
alkali or alkaline earth is taken as is indicated by the formula.
One can also start from phtalaminic acid, which is very easily formed from
phtalimide (see Aschau Ber. d. D. Ch. Ges. XIX 1401) and convert this into
anthranilic acid in the same way as the imide.
By way of example, my correspondents obtained a good yield in observing the
following conditions:
1 part by weight of finely divided phtalimide is dissolved together with 2 parts
by weight of solid hydrate of soda in 7 parts by weight of water under cooling;

page_text: under continual stirring, 10 parts by weight of a sodium hypochlorite solution
having 506 p. c. of Na OCI are then added, and the mixture is heated for some
minutes to about 80° C., at which temperature the conversion is rapidly effected.
The liquid is then cooled down and is neutralised with hydrochloric acid or
sulphuric acid, and a sufficient excess of acetic acid is added, whereby a great part
of the anthranilic acid formed is made to separate by crystalisation.
The anthranilic acid is filtered and washed with cold water. The combined lyes
have copper acetate suitably added, whereby anthranilate of copper, that dissolves
with difficulty, is separated, and this is converted according to known methods in
anthranilic acid.
101 3
1000
ABEL & IMRAY,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Process for the Production of Anthranilic Acid.
I, OLIVER IMRAY, of No. 28 Southampton Buildings, Chancery Lane, in the
County of London, Fellow of the Institute of Patent Agents, do hereby declare the
nature of this invention and in what manuer the same is to be performed to be
particularly described and ascertained in and by the following statement :---
The researches of A. W. Hofmann on the reaction of bromine and alkalies on
amides (Berichte der deutschen chemischen Gesellschaft 14, 2725; 15, 407, 752,
762) showed that acid amides are converted into amines, carbonic acid being
evolved.
S. Hoogenwerf and W. A. van Dorp found later that the amines also result from
the action of hypobromite of potash on the acid amines (Recueil d. Trav. Chim. des
Pays-Bas 5, 252; 6, 373, 8, 173). These chemists also demonstrated a quite
similar transformation of acid amides, by converting succinimide into beta-amido-
propionic acid (Verslagen en Mededeelingen der Köninkl. Akad v Wetensch. Afd
Nat kunde III Recks Deel VII p. 216).
An analogous process forms the basis of this invention which consists in a process
for the production of anthranilic acid from phthalimide.
Anthranilic acid is formed when one molecular proportion of phthalimide is
treated with one molecular proportion of a hypochlorite or hypobromite (potassium,
sodium, calcium, barium, strontium and magnesium salts can be used) in the
presence of a fixed alkali or alkaline earth and water, with or without the applica-
tion of heat. Under alkalis and alkaline earths are to be understood caustic
potash and soda, lime, baryta and strontia.
Anthranilic acid is also formed if chlorine or bromine be led into an alkaline
solution of phthalimide, a hypochlorite, or hypobromite being thus formed in the
solution, and the mixture being then heated. Also, phthalimide may first be treated
with bromine and subsequently an excess of alkali slowly added and the mass
heated, when anthranilic acid results. This resembles the process originally
applied by Hofmann to the amides of the mono-carboxylic acids.
The reaction in all these modifications of the process can be represented by the
following equation in which it is assumed that caustic soda and hypochlorite of
soda are used.

page_text: resaid, be used, and instead of a hypochlorite, a hypobromite. In orde
to obtain a good yield, care must be taken to use the exact proportions o
phthalimide and the hypochlorite or hypobromite determined by the equation, and
to take at least the proportion of alkali or alkaline earth indicated therein.
Instead of taking phthalimide, phthalaminic acid may be employed which can be
readily prepared from it (see Aschau, Berichte der deutschen chemischen
Gesellschaft 19, 1401).
The mode of procedure with phthalaminic acid to obtain anthranilic acid is the
same as described for phthalimide.
The following example will serve to illustrate the nature of the invention and
the manner in which it can be carried into practical effect. The parts are by
weight.
Dissolve one part of finely divided phthalimide and two parts of solid caustic
soda in seven parts of water, keeping the mixture cool. Stir continuously and add
ten parts of a solution of sodium hypochlorite containing 5.06 per cent. (five and six
hundreths per cent.) of sodium hypochlorite, (Na OCI), then heat the mixture for
some minutes to a temperature of about eighty degrees Centigrade or stir till no
unused hypochlorite can be found in the liquid.
Neutralize the cold mixture with hydrochloric or sulphuric acid, and add ecetic
acid in sufficient excess. A considerable portion of the anthranilic acid formed then
crystallizes out. Filter and wash with cold water. Treat the crystals of anthranilic
acid in a hydro-extractor and dry.
A further quantity of anthranilic acid can be obtained by adding copper acetate
to the combined mother liquor and wash-water, when a precipitate of the almost
insoluble copper salt forms. This is collected and converted into the free acid
according to known methods.
Anthranilic acid is a valuable body for use in the manufacture of colouring matters
nd of chemical preparations.
Having now particularly described and ascertained the nature of my said inven-
ion and in what manner the same is to be performed I declare that what I
laim is
The manufacture of anthranilic acid by the action of a hypochlorite or hypo-
romite (or of their equivalents as hereinbefore indicated) on phthalimide or
hthalaminic acid in the presence of a fixed alkali or alkaline earth, substantially
s hereinbefore described.
Dated this 20th day of July 1891.
ABEL & IMRAY,
Agents for the Applicant.