IMPROVEMENTS IN THE Manufacture of SulPRO-ACIDS
Year: 1881

page_text: LETTERS PATENT to Frank Wirth, of the Firm of Wirth and Company,
Patent Solicitors, at Frankfort-on-the-Main, in the Empire of Germany, for
an Invention of "IMPROVEMENTS IN THE Manufacture of SulPRO-ACIDS."
A communication from Messrs. Kalle and Company, of Biebrich, in the Empire
of German
PROVISIONAL SPECIFICATION left by the said Frank Wirth at the Office
of the Commissioners of Patents on the 3rd December 1881.
FRANK WIRTH, of the Firm of Wirth and Company, Patent Solicitors, at
Frankfort on the Main, in the Empire of Germany.
"IMPROVEMENTS IN THE
MANUFACTURE or Sulpho-acids.” [A communication from Messrs. Kallo and
Company, of Biebrich, in the Empire of Germany.]
Up to the present time sulphuric anhydride or its compounds have mostly been
employed for the production of the sulpho acids of bodies that cannot be sulphonised
with excess of sulphuric acid.
The present Invention is based on the observation that all theso sulphonisations
can also be effected by means of monohydrated sulphuric acid if a body is added to
them that will combine with the water liberated by the reaction. Such a body has
been found in the glassy metaphosphoric acid. If for instance metaphosphoric
acid is dissolved in sulphuric acid (as nearly as possible corresponding to the
hydrate H, SO,) in the proportions of one part of the former to two of the latter, a
viscous fluid is obtained which, although it does not contain sulphuric anhydride,
as such operates just as strongly sulphonising but more uniformly so than fuming
sulphuric acid of 25 to 30 per cent. anhydride.
The following facts show that there is in this process no formation of sulphuric
anhydride :-
I. The mixturo does not give off fumes in the air, unites with water without
noise, and does not carbonise paper, wood, and other organic substances.
II. Whereas the anhydride can be almost completely distilled from fuming
sulphuric acid at a temperature of 150° cent., in the compound in question only

page_text: traces of anhydride vapour, and these mixed with distilled hydrate, are given off
at a temperature of from 280° to 300° cent.
The process offers considerable technical and economical advantages, as on the
one hand it avoids the tedious operations with strong fuming sulphuric acid, and a
carbonisation of the substance is less to be feared, and on the other hand the
phosphoric acid can by this means be regained almost quantitatively, and be again
converted into metaphosphoric acid. Consequently only the sulphuric acid hydrate
is used in the sulphonising process.
By this method have been prepared the sulpho acids of rosaniline, its methylated,
ethylated, and phenilated derivatives, as also of anthrachinon, alizarine, and
purpurine. In addition the mono- and disulpho acids of amidoazobenzole and its
homologues discovered by F. Grässler, can be obtained by this process.
Example 3 parts of metaphosphoric acid, as free as possible from water, are
dissolved under the application of heat in 7 parts of pure sulphuric acid monohy-
drate. To the mixture are added by degrees 2 parts of dry rosaniline sulphate or
hydrochlorate; the sulphonising takes place already at the temperature of the
water bath, but more rapidly and completely at from 120° to 130° cent. It may
be considered as complete when a sample is completely dissolved with a yellow
colour in dilute alkaline lye. Instead of rosaniline salts, rosaniline waste colours,
such as are known as cerise, grenadine, maroon, and the like may be used. The
substance obtained is in all cases poured into water, and from this is then obtained
in the known manner the lime salt, and from this the soda salt of the sulpho acids.
The whole of the phosphoric acid is at the same time obtained as calcium
phosphate mixed with calcium sulphate. By treating this residue with the
calculated quantity of sulphuric acid, the phosphoric acid may be made soluble, aud
be converted into metaphosphoric acid by evaporation and heating to a red heat.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Frank Wirth in the Great Seal Patent Office on the 19th May
1882.
FRANK WIRTH, of the Firm of Wirth and Company, Patent Solicitors, at
Frankfort on the Main, in the Empire of Germany. "IMPROVEMENTS IN THE
MANUFACTURE OF SULPHO-ACIDS." A communication from Messrs. Kalle and
Company, of Biebrich, in the Empire of Germany.
Up to the present time sulphuric anhydride or its compounds have mostly been
employed for the production of the sulpho acids of bodies that cannot be sulphonised
with excess of sulphuric acid.
The present Invention is based on the observation that all these sulphonisations
can also be effected by means of monohydrated sulphuric acid, if a body is added
to them that will combine with the water liberated by the reaction. Such a body
has been found in the glassy metaphosphoric acid. If for instance metaphosphoric
acid is dissolved in sulphuric acid (as nearly as possible corresponding to the
hydrate H, SO,) in the proportions of one part of the former to two of the latter, a
viscous fluid is obtained which, although it does not contain sulphuric anhydride,
as such operates just as strongly sulphonising but more uniformly so than fuming
sulphuric acid of 25 to 30 per cent. anhydride.
The following facts show that there is in this process no formation of sulphuric
anhydride:-
I. The mixture does not give off fumes in the air, unites with water without
noise, and does not carbonise paper, wood, and other organic substances.
II. Whereas the anhydride can be almost completely distilled from fuming
sulphuric acid at a temperature of 150° cent., in the compound in question only
traces of anhydride vapour, and these mixed with distilled hydrate, are given off
at a temperature of from 280° to 300° cent.
The process offers considerable technical and economical advantages, as on the
one hand it avoids the tedious operations with strong fuming sulphuric acid, and a
carbonisation of the substance is less to be feared, and on the other hand the
phosphoric acid can by this means be regained almost quantitatively, and be again
converted into metaphosphoric acid. Consequently only the sulphuric acid hydrate
is used in the sulphonising process.
By this method have been prepared the sulpho acids of rosaniline, its methylated,
ethylated, and phenylated derivatives, as also of anthrachinon, alizarine and
purpurine. In addition the mono- and di-sulpho acids of amidoazobenzole and its
homologues discovered by F. Grässler can be obtained by this process.
Example.-3 parts of metaphosphoric acid as free as possible from water are
dissolved under the application of heat in 7 parts of pure sulphuric acid mono-
hydrate. To the mixture are added by degrees 2 parts of dry rosaniline sulphate
or hydrochlorato; the sulphonising takes place already at the temperature of the
water bath, but more rapidly and completely at from 120° to 130° cent. It may
be considered as complete when a sample is completely dissolved with a yellow colour
in dilute alkaline lye. Instead of rosaniline salts, rosaniline waste colours, such as
are known as cerise, grenadine, maroon, and the like may be used. The substance
obtained is in all cases poured into water, and from this is then obtained in the
known manner the lime sult, and from this the soda salt of the sulpho acids.
The whole of the phosphoric acid is at the same time obtained as calcium
phosphate mixed with calcium sulphate. By treating this residue with the
calculated quantity of sulphuric acid the phosphoric acid may be made soluble and
be converted into metaphosphoric acid by evaporation and heating to a red heat.

page_text: Having thus described the nature of the said Invention, and in what manner the
same is to be performed, as communicated to me by my correspondents, I claim,-
The production of sulpho-acids by means of hydrated sulphuric acid in the
presence of metaphosphoric acid.
In witness whereof, I, the said Frank Wirth, have hereunto set my hand
and seal, this Seventeenth day of May, in the year of our Lord One thousand
eight hundred and eighty two.
FRANK WIRIN. (L.S.)