Year: 1897

page_text: 9.3 parts of aniline dissolved in 150 parts of a 20 per cent. sulphuric acid are
diazotised in the usual manner. Into the resulting diazo solution, 15 parts of
sulphurous anhydride are introduced, and then 15 parts of cuprous oxide, in the
shape of a paste, are added in small portions, with stirring, care being taken that
the temperature of the reaction mixture does not exceed 5 degrees Centigrade.
When the development of nitrogen has ceased, and diazobenzene is no longer
found to be contained in the mixture, the latter is extracted by means of ether. On
evaporating the ethereal solution, the benzene sulphinic acid is obtained in a dry
state.

page_text: proportions) tetramethyldiamidobenzhydrol and alpha, alpha, naphthylaminesulphonic
acid, which product has probably the formula
are dissolved in a mixture prepared from 100 parts of concentrated sulphuric acid
(60 degrees Baumé) and 500 parts of water, and diazotised in the usual manner by 5
means of 7 parts of sodium nitrite, keeping the temperature at zero. Into the
resulting solution, 25 parts of sulphurous anhydride are introduced, and then 42 parts
of red cuprous sulphite, formed into a paste by means of water, are gradually added,
the temperature being kept between zero and 5 degrees Centigrade. When the
development of nitrogen has ceased, the resulting sulphinic acid has separated in a 1
crystalline state. It is filtered, and can be purified by dissolving in a sodium
carbonate solution, and precipitating from the resulting solution by means of acids.
Thus it is obtained in the shape of colourless crystals.
Of course my foreign correspondents do not intend to confine themselves to the
particulars given in the above examples, as these can be varied within wide limits, 1
without altering thereby the nature of the present invention.
NEWTON & SON,
Agents for the Applicant.
The Manufacture or Production of Sulphinic Acids of the Aromatic
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 and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement:-
In the Specification of Letters Patent No. 26139, dated 19th November, 1896, my
foreign correspondents have described a 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.
.

page_text: My foreign correspondents now have found that the same result is obtained if,
instead of metallic copper, cuprous oxide (Cu, 0), cuprous hydrate, the so-called red
cuprous sulphite, or other copper compounds, containing cuprous sulphite, are used
in the said process.
In carrying out their new process, which applies to the diazo derivatives of all
aromatic amines, my foreign correspondents proceed, for instance, in the manner
described in the following examples, the parts being by weight.
EXAMPLE A.
9.3 parts of aniline are mixed with 250 parts of a 20 per cent. sulphuric acid, and
diazotised in the usual manner. Into the resulting diazo solution, 15 parts of
sulphurous anhydride are introduced, and then 15 parts of cuprous oxide, in the
shape of a paste, are added, in small portions, with stirring, care being taken that the
temperature of the reaction mixture does not exceed 5 degrees Centigrade.
When the development of nitrogen has ceased, and diazo benzene is no longer
5 found to be contained in the mixture, the latter is extracted by means of ether. On
evaporating the ethereal solution, the benzene sulphinic acid is obtained in a dry
state.
are dissolved in a mixture prepared from 100 parts of concentrated sulphuric acid
(60 degrees Baumé) and 500 parts of water, and diazotised in the usual manner by
means of 7 parts of sodium nitrite, keeping the temperature at zero. Into the
resulting solution, 25 parts of sulphurous anhydride are introduced, and then
72 parts of red cuprous sulphite, formed into a paste by means of water, are
gradually added, the temperature being kept between zero and 5 degrees Centi-
grade. When the development of nitrogen has ceased, the resulting sulphinic
acid has separated in a crystalline state. It is filtered, and can be purified by
dissolving in a sodium carbonate solution and precipitating from the resulting solution
by means of acids. Thus it is obtained in the shape of colorless crystals.

page_text: Of course, my foreign correspondents do not intend to confine themselves to the
particulars given in the above examples, as these can be varied within wide limits,
without altering thereby the nature of the present invention. Thus, for instance,
instead of the copper compounds used in the examples, other of the above mentioned
copper compounds can be employed.
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, (as communicated to me
from abroad), I declare that what I claim is:-
The process for producing sulphinic acids of the aromatic series, which process
consists in allowing cuprous oxide, cuprous hydrate, the so-called red cuprous sulphite,
or other copper compounds containing cuprous sulphite, to act on the diazo derivatives
of primary aromatic amines in the presence of sulphurous acid, substantially as
hereinbefore described.