Year: 1896

page_text: I HENRY EDWARD NEWTON of The Office for Patents, 6 Bream's Buildings,
Chancery Lane in the County of London, Patent Agent, do hereby declare the
nature of this invention to be as follows:-
My foreign correspondents have discovered that sulphuric acid diazo-derivatives of
primary aromatic amines may be readily changed into sulphiuic acids by means of
sulphurous acid and copper powder.
The reaction probably takes place according to the following equations →
I.
CH,N=N-SO,H+H₂SO,-C,H,N=N-80,H+H, SO,
diazo sulphite being first formed from diazo sulphate, then one molecular proportion
of oxygen is taken away therefrom by the action either of sulphurous acid or of
copper, and at the same time two molecular proportions of azote are eliminated by
the action of copper.
In carrying out their new process, which applies to the diazo derivatives of all
aromatic amines, my foreign correspondents, for instance, proceed as follows. The
A current of sulphurous acid anhydride is introduced into a carefully cooled diazo
solution prepared from 10 parts of orthonnisidine, 20 parts of concentrated sulphuric
acid, 150 parts of water, and 6-7 parts of sodium nitrite, and then copper powder is
stirred into the thus obtained mixture, during continuous cooling, until an evolution
of azote which takes place censes. The anisol sulphinic acid thus produced is
contained in the resulting solution as well as in the precipitate, and may be isolated

page_text: therefroin by an extraction with ether or other suitable solvent, or in any other
suitable manner. It has the constitutional formula :-
The Manufacture or Production of Sulphinic Acids of the Aromatic 1
Series.
I HENRY EDWARD NEWTON of The Office for Patents, 6 Bream's Buildings
Chancery Lane in the County of London, Patent Agent, do hereby declare the
nature of this invention aud in what manner the same is to be performed, lo
he particularly described and ascertained in and by the following statement :-
My foreign correspondents discovered some time since, that sulphuric acid diazo
derivatives of primary aromatic amines might be readily changed into sulphinic acids
by means of sulphurous acid and copper powder.
The reaction probably took place according to the following equations:-
=
I. CH,N-N-SO,H+ H₂SO, CH,N=N-SO₂H+ H₂SO,

page_text: into the mixture, which is ineanwhile kept cool, until an evolution of nitrogen (which
takes placo) ceases. The anisol sulphinic acid thus produced is contained in the
resulting solution, as well as in the precipitate, and may be isolated therefrom by an
extraction with ether or other suitable solvent, or in any other suitable manner.
6 It has the constitutional formula
and crystallizes from water in the shape of colorless needles, which melt at about 87
or 88 degrees Centigrade. The new acid readily dissolves in ether, alcohol, chloroform,
and acetone, and is practically insoluble in ligroine and in carbon disulphide. Its
0 alkaline salts and the barium salt are readily soluble in water.
PRODUCTION OF NAPHTHALENE-ALPHA SULPHINIC ALPHA-SULPHONIC ACID.
1 part of alpha naphthylamine alpha, sulphonic acid is mixed with 3 parts of
concentrated sulphuric acid and 15 parts of water, and dinzotized in the known
manner by means of sodium nitrite. Into the diazo solution thus obtained, a
current of sulphurous anhydride is introduced in excess, the solution being carefully
cooled meanwhile. Subsequently, 6 parts of copper powder are added with
stirring, the mixture being also kept cool. When the development of nitrogen
ceases, the formation of the sulphinic sulphonic acid is finislied. On rendering
the reaction mixture alkaline by adding sodium carbonate, the sodium salt of the
new acid is formed, which is separated by means of common salt. It is easily
soluble in water, and crystallisos from a hot concentrated watery solution in the
forin of leaf-shaped glittering crystals. The barium salt of the new acid is
obtained in the shape of a white flaky-precipitate, which is with difficulty soluble
in water, on adding barium chloride to the solution of the sodium salt.
On acting with permanganate of potassium on the new acid, it is transformed into
the known alpha, alpha, naphthalene disulphonic acid.

page_text: It
is mixed with 2 parts of concentrated sulphuric acid and 10 parts of water.
is then diazotised in the usual manner by means of sodium nitrite. Subsequently
the liquid is saturated with sulphurous anhydride, and 5 parts of copper powder
are stirred into the resulting mixture, which is cooled meanwhile. Stirring is
continued until the development of nitrogen ceases. When this stage is reached,
the formation of the new sulphinic acid of the triphenylmethane series is completed.
The liquid is filtered in order to remove the copper powder, and the filtrate, after
being heated, is rendered alkaline by means of sodium carbonate. The sodium salt
of the new sulphinic acid thus produced is profitably precipitated by the addition of
common salt. It crystallises, on cooling, in the shape of little, slightly-greenish
colored, glittering rhomboid leaves, which assume an intense green color on exposure
to the air.
My foreign correspondents wish it to be understood that they do not limit
themselves to the particulars given in the foregoing examples, as these are merely
typical, and can be varied within wide limits, without altering thereby the nature of the
present invention, which in general relates to the production of sulphinic acids of the
aromatic series, by acting on the diazo derivatives of primary aromatic amines with
finely divided copper, such as copper powder, in the presence of sulphurous acid.
Having now particularly described and ascertained the nature of the said invention
and in what inauner the same is to be performed, as comirunicated to me
from abroad, I declare that what I claim is:-
1. The process for producing sulphinic acids of the aromatic series, by acting on
the diazo derivatives of primary aromatic amines with finely divided copper, in the
presence of sulphurous acid.
2. The new products obtained in the manner hereinbefore described, or in any
other manner yielding the same result.
D. ALS
1100