Improvements in the Manufacture of Dihydroxy naphthalene Sulpho Acids.
Year: 1892

page_text: Date of Application, 20th June, 1892
Complete Specification Left, 20th Mar., 1893—Accented, 6th May, 1893
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Dihydroxy naphthalene Sulpho
Acids.
I, BENJAMIN WILLCOX of 47 Lincolns Inn Fields in the County of Middlesex
Patent Agent do hereby declare the nature of this invention which has been com-
municated to me from abroad by The Farbenfabriken vormals Friedrich Bayer & Co.
of Elberfeld in the Empire of Germany to be as follows:-
In the German Patent No. 46307 dated 16th August 1888 the transformation of
an alpha-naphthylamine-sulpho acid viz.: the so called alpha naphthyionic acid
piria (NH, SOH = 1:4) into the corresponding alpha-naphthol-sulpho acid
(OH SO,H= 1:4) is for the first time described. This is effected by means of
strong soda-lye, ammonia being disengaged and the amido group being replaced by
the hydroxylic group whilst the sulpho group is not altered.
=
Afterwards it was found that the alpha-naphthylamine disulpho acid II of the
German Patent No. 41957 dated 4th September 1886 is altered by melting with
alkalies in a similar manner and this process is described in the German Patent
No. 57014 dated 24th December 1889 the amido group being likewise replaced by
the hydroxylic group.
:
Though the said two alpha-naphthyl-amine-sulpho acids shew such an analogous
bebaviour when subjected to the treatment with alkalies, all alpha-naphthylamine
sulpho acids are not altered in the same manner, for the alpha-naphthylamine-
alpha-mono-sulpho acid (NH, SO₂H = 1:5) yields in the melting process amido-
naphthol (NH: OH = 1:5) as described in the German Patent No. 49448 dated
13th February 1889 and my foreign correspondents have found that alpha-naphthyl-
amine-8-disulpho-acid of the German Patent No. 45776 dated 16th March 1888
and alpha-naphthylamine-trisulpho acid of the German Patent No. 56058 dated
1st February 1890 are by melting with alkalies changed into the corresponding
amido-naphthol-sulpho-acids. In these processes the amido group (although in
alpha position) remains unaltered. Even if the 1:8-amido-naphthol-beta-disulpho-
acid obtained from the above named alpha-naphthylamine-trisulpho acid be further
treated with alkalies or concentrated alkali-lye with or without pressure according
to the processes described in the German Patents Nos. 46307 and 57114 ammonia
is not disengaged but another sulpho group is replaced by the hydroxylic group, an
amido-dihydroxy-naphthalene-mono-sulpho acid being formed.
My foreign correspondents have now discovered the interesting and very
remarkable fact that if the concentrated alkali-lye be replaced by a very diluted
lye the melting process proceeds in the contrary manner namely that 1:8-amido-
naphthol-beta-disulpho acid is then changed into the corresponding 1: 8-dihydroxy-
naphthalene-beta-disulpho acid the amido group being replaced by the hydroxylic
group. It is necessary to employ for this reaction an alkali-lye which contains less
or not much more than 10 per cent. of soda, potash or the like and the temperature
is preferably regulated during the process in such a manner that the pressure in the
closed vessel is from about 22 to 27 atmospheres.
In order to illustrate this process the following example is given; the parts being
by weight.

page_text: in a closed vessel for from about 4 to 5 hours under a pressure of 25 atmospheres.
After driving off the ammonia by boiling the mass is acidulated by means of
muriatic acid, and the acid sodium salt of the dihydroxynaphthalenedisulpho acid
which is formed and separates is filtered off.
My foreign correspondents have found that it is not necessary to isolate the
18-amido-naphthol-beta-disulpho acid, but the mass obtained by melting the above
naphthylamine trisulpho acid with alkalies and containing the amido-naphthol-
disulpho acid in alkaline solution can after the addition of water be directly heated
under pressure the same 1: 8-dihydroxy naphthalene-beta-disulpho acid being thus
formed.
My foreign correspondents have further found that the above dihydroxy-
naphthalene-disulpho acid can also be produced by treating with alkali-lye the
diamido naphthalene disulpho acid which is obtained by nitrating the so called
naphthalene 2-7-disulpho acid and reducing the dinitro compound formed. The
process for transforming the said diamido-naphthalene-disulpho acid into the
1-8-dihydroxy-naphthalene beta-disulpho acid is effected in the same manner as that
described in the preceding example employing instead of amido-naphthol-disulpho
acid the equivalent quantity of the said diamido-naphthalene-disulpho acid.
It follows from the foregoing reactions that the said diamido-naphthalene-disulpho
acid is an 18-diamido-naphthalene-beta-disulpho acid corresponding to the above
1-8-amido-naphthol-beta disulpho acid and likewise that the amido-naphthol-
disulpho acid described in the Specification of the application for a German
Patent No. C. 3544 dated 12th December 1890 is identical with the 1-8-amido-
naphthol-beta disulpho acid employed in the preceding example and derived from
the alpha-naphthylamine-tri-sulpho acid of the German Patent No. 56058 dated
1st February 1890.
Dated oth
1000
J. H. JOHNSON & Co.,
47, Lincoln's Inn Fields, Agents.
COMPLETE SPECIFICATION.
Improvements in the Manufacture of Dihydroxynaphthalene
Sulpho Acids.
I, BENJAMIN WILLCOX of 47 Lincolns Inn Fields in the County of Middlesex
Patent Agent do hereby declare the nature of this invention (which has been
communicated to me from abroad by Farbenfabriken vorm. Friedr. Bayer & Co.
of Elberfeld 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 :-
The transformation of an alpha naphthyl-amine sulpho acid viz. the so called alpha-
naphthionic acid (NH,:SO,H=1:4) into the corresponding alpha-naphthol-sulpho
acid (OH: SO,H=1:4) was for the first time described in the German Patent
No. 46307 dated 16th August 1888. It is effected by means of strong soda-lye,
ammonia being disengaged, the amido group being displaced by the hydroxylic
group, whilst the sulpho group is not altered."
It was subsequently found that the alpha-naphthylamine disulpho acid II of the
German Patent No. 41957 dated 4th September 1886 is altered in a similar manner
by fusion with alkalies, and this process is described in the German Patent
No. 57014 dated 24th December 1889.
Though the said two alpha-naphthyl-amine-sulpho acids shew such an analogous
behaviour (when subjected to the treatment with alkalies), all alphanaphthylamine
sulpho acids are not altered in the same manner, inasmuch as the alpha-naphthyl-
amine alpha-mono-sulpho acid NH, SO,H=1:5 ou like treatment yields amido-
naphthol (NH2: OH = 1:5) as described in the German Patent No. 49448 dated

page_text: 13th February 1889, moreover my foreign correspondents have found and described
in the Specification of the Patent No. 13443 dated 26th August 1890 that alpha-
naphthylamine-epsilon or zeta-disulpho acid of the German Patent No. 45776
dated 16th March 1888 and alpha-naphthylamine-tri-sulpho acid of the German
Patent No. 56058 dated 1st February 1890 are converted by fusion with alkalies,
into the corresponding amidonaphthol sulpho acids. In these processes the amido
group (although in alpha position) remains unaltered.
My foreign correspondents have now discovered the interesting and very remark-
able fact that, if instead of the concentrated alkali-lye a very diluted lye be used,
the hydrolysis proceeds in the contrary manner, namely that 1: 8-amido-naphthol
beta disulpho acid or the salts thereof are then changed into the corresponding
1: 8-dihydroxy-naphthalene beta-disulpho acid or its salts, the amido group being
displaced by the hydroxylic group. The 1: 8-dihydroxynaphthalene-beta-disulpho
acid thus produced is represented by the following formula:
It is profitable to employ for this purpose an alkali-lye which contains less or
not much more than 10 per cent. of soda, potash or the like, and the temperature is
preferably regulated during the process in such a manner that the pressure in the
closed vessel is from about 22 to 27 atmospheres.
PRODUCTION of 1:8-DI-HYDROXY-NAPHTHALENE-BETA-DI-SULPHO ACID
FROM 1:8-AMIDO-NAPHTHOL-BETA-DISULPHO ACID.
15 parts of 18-amidonaphthol beta disulphonate of sodium are dissolved in
150 parts of soda-lye containing 5 per cent. of soda, and the solution is heated in a
closed vessel or autoclave during about 8 hours under a pressure of 22.5 atmospheres
at about 265 degrees centigrade. After driving off the ammonia by boiling, the
mass is acidulated with muriatic acid, and the acid sodium salt of the dihydroxy-
naphthalene disulpho acid which separates, is filtered off.
My foreign correspondents have found that it is not necessary to isolate the
1: 8-amidonaphtholbeta disulpho acid, but the mass obtained by melting the above
named naphthylamine trisulpho acid with alkalies according to the Letters Patent
No. 13443 of 1890 containing the amidonaphthol disulpho acid in alkaline solution
may after the addition of water be directly heated under pressure, the same
1: 8-dihydroxynaphthalene beta disulpho acid being thus formed.
The above example merely describes one method of practically producing
the 1: 8-dihydroxynaphthalene beta disulpho acid. My foreign correspondents do
not limit themselves to the directions given in the said example, as the production
of 1: 8-dihydroxy-naphthalene-beta-disulpho acid by means of this new process can
be varied. For instance, instead of the sodium salt the corresponding quantities of
other alkaline, earthy alkaline, or other metallic salts of the free acid can be used;
the quantity of the diluted soda-lye can vary within certain limits; and in place of
diluted soda-lye other diluted alkaline lyes can be employed. The strength of the
alkali lye most practically used is not much above 10 per cent., but less strong
alkali-lyes can be used; for example, in treating the free 1: 8-amidonaphthol beta
disulpho acid only such a quantity of diluted alkali-lye is necessary, as is sufficient
to form a salt of the said 1: 8-amidonaphthol beta disulpho acid. Hence it follows
that, instead of treating the amidonaphtholdisulpho acid with diluted alkali-lye at

page_text: SO₂Me
SO,Me
\so,Me
can be heated alone with water (for example with 10 times their weight of water
under pressure at from 260 to 280 degrees centigrade for 8 hours). In this manner,
probably an alkali-lye is formed, which though extremely dilute is sufficient to
effect the conversion.
The temperature and the pressure employed for the above purposes can also be
varied within certain limits, but good results in general are obtained, if the
temperature is from 260 to 280 degrees centigrade and if the pressure in the closed
vessels is from about 22 to 27 atmospheres.
My foreign correspondents have further found that the above dihydroxynaph-
thalene disulpho acid can also be produced by treating with diluted alkali-lye the
diamido-naphthalene disulpho acid or salts of this acid which can be obtained by
nitrating naphthalene- 2:7- or 3: 6-disulpho acid and reducing the resulting
dinitro compound. The transformation of the said diamido-naphthalene disulpho
acid into the 1: 8-dihydroxynaphthalene beta disulpho acid is effected in the same
manner as that which is described in the preceding example and is herein before
defined viz. by employing instead of amidonaphthol disulpho acid or its salts the
equivalent quantity of the said diamidonaphthalene disulpho acid or salts thereof.
The same change is effected, if alkaline salts of the said diamidonaphthalene
disulpho acid are heated alone with water at from 260 to 280 degrees centigrade;
in this case also the resulting alkali-lye (though extremely dilute) is sufficient to
effect the transformation of the diamidonaphthalene disulpho acid into the dihy-
droxynaphthalene disulpho acid.
It follows from the foregoing statement, that the said diamidonaphthalene-
disulpho acid is an 1: 8-diamidonaphthalene-beta-disulpho acid corresponding to the
above 18-amidonaphthol-beta-disulpho acid and also that the so called amido-
naphthol-disulpho acid H described in the Specification of the Patent No. 1742 dated
30th January 1891 is identical with the 1: 8-amidonaphthol beta disulpho acid
employed in the preceding example and derived from the alphanaphthylamine
trisulpho acid of the German Patent No. 56058 dated 1st February 1890.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
:
1. The process for producing 1: 8-dihydroxy-naphthalene-beta-disulpho acid (so
called chromotrop acid) by heating 1 : 8-amido-naphthol-beta-disulpho acid (NH,:
OH: SO₂H: SO,H=1: 8:3:6) or 1: 8-diamido naphthalene-beta-disulpho acid
(NH, NH, SO,H: SO,H=1: 8:3: 6) or alkaline salts of either of these two
acids with diluted alkali-lye in closed vessels at elevated temperatures, or by heating
alkaline salts of the said 1: 8-amidonaphthol-beta-disulpho acid or 1: 8-diamido-
naphthalene-beta-disulpho acid alone with water in closed vessels at elevated
temperatures.
:
2. The processes for preparing 1:8-dihydroxynaphthalene-beta-disulpho acid (so.
called chromotrop acid) in the form of its salts,
:
a.) by heating 1: 8-amidonaphthol-beta-disulpho acid (NH, OH: SO₂H
SO,H=1:8:3: 6) or 1 : 8-diamidonaphthalene-beta-disulpho acid (NH.

page_text: acids with diluted alkali-lye in closed vessels under a pressure of from about
22 to 27 atmospheres at from about 260 to 280 degrees centigrade, and sub-
sequently isolating the resulting 1: 8-dihydroxynaphthalene-beta-disulpho
acid in the form of its salts, or
.) by heating alkaline salts of the 1: 8-amidonaphthol-beta-disulpho-acid
(NH, OH: SO,H: SO,H=1: 8:3:6) or 1: 8-diamidonaphthalene-beta
disulpho acid (NH₂: NÍ₂ : SO₂H: SO, H=1:8:3 : 6) alone with water
in closed vessels under a pressure of from about 22 to 27 atmospheres at from
about 260 to 280 degrees centigrade and subsequently isolating the resulting
18-dihydroxynaphthalene-beta-disulpho acid in the form of its salts.
Dated this 18th day of March 1893.
B. WILLCOX.