Year: 1897

page_text: I, SYDNEY PITT, of Sutton, in the County of Surrey, Gentleman, do hereby declare
the nature of this invention (which has been communicated to me from abroad by
Leopold Cassella & Co., of Frankfort-on-Main, in the Empire of Germany) to be as
follows:-
It is well known that oxyazobenzene reduced in acid solution is almost completely
split into aniline and para-amidophenol.
From the researches of P. Jacobson (Berl. Berichte 25 P. 992; 26 P. 681, 688,
699; Annalen 287. P. 97) it is further known that the alkyl-ethers of
oxyazobenzene are transformed by the same treatment into semidines (derivatives
of the ortho and paraamidodiphenylamine).
It has now been found that the acid esters of oxyazobenzene behave in a materially
different manner, being transformed into oxydiamidodiphenyl-bases by reducing
agents; for instance, there is obtained from acetyl-oxyazobenzene a base isomeric
to oxyhydrazobenzene which according to its reactions must be considered as
oxydiamidodiphenyl

page_text: Oxydiamidodiphenyl melts at 148 degrees C., it is easily soluble in alcohol, giacial
acetic acid and hot water, more difficultly soluble in benzene. From hot water it
crystallises on cooling in fascicular needles. It is soluble in soda lye. The alkaline
solution turns dark brown on standing in open vessels.
That the base is a primary diamine, has been proved by investigating its deriva-
tives, when it was found that only one molecule of the base condenses with two
molecules of aldehyde and takes up two acetyl-groups on being acetylated with
boiling glacial acetic acid.
The salicylaldehyde derivative
The oxydiamidodiphenyl may be used' to advantage for producing, dyestuffs and
as a photographic developer.
Analogous to the acetyl-oxyazobenzene behave the acetyl derivatives of other
para-oxyazo compounds which are not substituted in one of the groups para to the
azo group.
The reaction takes place in another way by starting from double substituted para
azo bodies, such as for instance, the acetylated product from diazotized para-toluidine
and phenol..
Goldschmidt & Brubacher have made experiments in this direction (see Berichte
24 P. 2311), but their indications could not be confirmed,, the reduction yielding the
two normal semidines: the ortho-semidine of the melting point 136 degrees C.
characterised by the formation of an azimide melting at 188 degrees C. by the re-

page_text: action,of, nitrous acid; and the para-semidine melting at 118 to 119 degrees C.
which was found to be identical with the para-amidophenyl-para-tolylamine produced
by, Reichold (Aunnlen 255, P. 166 to 167).
Producing Diamidooxydiphenyl and like Bases.
I, SYDNEY PITT, of Sutton, in the County of Surrey, Gentleman, do hereby
declare the nature, of this invention: (which has. been: communicated to me from
abroad by Leopold Cassella & Co., of Frankfort-on-Main, 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 well known that oxyazobenzene reduced in acid solution is almost completely
split into aniline and para-amidophenol.
From the researches of P. Jacobson. (Berl., Berichte 25 P. 992; 26 P. 681, 688,
699; Annalen 287 P. 97) it is further known that the alkyl-ethers of oxyazo-
benzene are transformed by the same treatment into semidines (derivatives of the
ortho- and paraamidodiphenylamine).
It has now been found that the acid esters of oxyazobenzene behave in a materially
different manner, being transformed into oxydiamidodiphenyl-bases by reducing
agents; for instance, there is obtained from acetyl-oxyazobenzene a base isomeric
to oxyhydrazobenzene which according to its reactions must be considered as
oxydiamidodiphenyl,
Example: 10 grams acetyl-oxyazobenzene (Wallach & Kiepenheuer Berl.
Berichte 14 P. 2617), are finely ground and gradually introduced into 60 ccm. of a
solution containing 40 grams chloride of tin dissolved in. 100 ccm. muriatic acid of
38% under continuous stirring. The temperature of the liquor is raised
thereby and care has to be taken that by cooling with cold water, the temperature
does not exceed 40 degrees C. After standing about a day, a large quantity of
double salts of tin consisting chiefly of oxydiamidodiphenyl and of a small quantity
of benzidine separates from the solution. By strong extraction and pressing any
muriatic acid adhering is as far as possible removed from it. This double salt is
then dissolved in about 20 parts of water; the tin is precipitated with sulphuretted
hydrogen and the solution from which the tin has been filtered off is strongly
evaporated in a stream of carbonic acid. By adding dilute sulphuric acid the
benzidene is separated in the form of its difficultly soluble sulphate. After having
ascertained that sulphuric acid no longer causes a precipitate from the solution the
benzidine sulphate is filtered off, the solution partially, neutralised with caustic
soda and then completely with a concentrated solution of carbonate of soda. The
oxydiamidodiphenyl thereby is separated partly as a white crystalline and.
partly as a resinous precipitate. It can be purified by crystallisation from
water or benzene..
Oxydiamidodiphenyl melts at 148 degrees C., it is easily soluble in alcohol,
glacial acetic acid and hot water, more difficultly soluble, in benzene. From hot

page_text: water it crystallises on cooling in fascicular needles. It is soluble in soda lye.
The alkaline solution turns dark brown on standing in open vessels
That the base is a primary diamine, has been proved by investigating its
derivatives, when it was found that only one molecule of the base condenses with
two molecules of aldehyde and takes up two acetyl-groups on being acetylated with
boiling glacial acetic acid.
ML
as a photographic developer.
Analogous to the acetyl-oxyazobenzene behave the acetyl derivatives of other
para-oxyazo compounds which are not substituted in one of the groups para to the
azo group.
The reaction takes place in another way by starting from double substituted para
azo bodies, such as for instance, the acetylated product from diazotised para-toluidine
and phenol.
Goldschmidt & Brubacher have made experiments in this direction (see
Berichte 24 P. 2311), but their indications could not be confirmed, the reduction
yielding the two normal semidines: the ortho-semidine of the melting-point
136 degrees C. characterised by the formation of an azimide melting at
188 degrees C. by the reaction of nitrous acid, and the para-semidine melting
at 118 to 119 degrees C. which was found to be identical with the para-amidophenyl-
para-tolylamine produced by Reichold (Annalen 255, P. 166 to 167.)

page_text: Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. The production of oxydiamidodiphenyl-bases by reducing acetyl-para-oxy-
azobenzene or its analogues in mineral acid solution.
2. The new oxydiamidodiphenyl bases and its homologues hereinbefore
described.
Dated this 13th day of July 1898.