Process for the Utilisation of the Sulphides and Sulphydrates of Alkaline Earths, and the Production of Aniline, Toluidine, or Amidobenzaldehydes by the Treatment of the said Substances with Nitro Bodies.
Year: 1895

page_text: Date of Application, 2nd Sept., 1895-Accepted, 26th Oct., 1895
COMPLETE SPECIFICATION.
Process for the Utilisation of the Sulphides and Sulphydrates of
Alkaline Earths, and the Production of Aniline, Toluidine, or
Amidobenzaldehydes by the Treatment of the said Substances
with Nitro Bodies.
I, Dr. HANS LOESNER of No. 42 Windmühlen Strasse, Leipzig, Germany,
Chemist, 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 :-
The sulphides and the sulphydrates of the alkaline earths have a ready reducing
action upon nitro compounds.
The neutral sulphides are thereby converted into the corresponding free bases and
thiosulphates, while the sulphydrates only form thiosulphates.
Calcium sulphide is best suited for the reduction and for this purpose the
residues of the Le-Blanc soda works can be directly used.
This hitherto unknown property of calcium sulphide enables. the soda residues
to be profitably worked as both caustic lime and thiosulphate can be utilised,
and the cost of the process is greatly reduced by the simultaneous production of
anilin.
In the existing modes of producing anilin it has not been possible, notwith-
standing the greatest care, to obtain a greater yield than from 92 to 93 p.c. of the
theoretical amount.
The reason of this is probably to be found in the fact that with the reduction
by means of iron and hydrochloric acid there is always some chloride of iron
produced, which acts destructively upon the anilin already formed, and thus reduces
the yield.
By the present invention this defect is obviated as the above named reducing
agents do not enter into combination with aniline, as neither caustic lime nor
thiosulphate have any action on anilin. Thus a detrimental subsidiary reaction that
materially influences the yield does not occur.
In addition, the anilin is obtained as a free base, and consequently the quantity
of hydrochloric acid and the caustic lime necessary for decomposing the hydro-
chlorate is saved.
The nitro benzol reduced by the sulphides yields an anilin that has a slightly
yellow colour, but it only becomes resinous with difficulty as compared with ordinary
anilin.
The yellow colouration is caused by the production of traces of azoxy- and
azo-benzol.
The quantity of these azo-bodies is, under the most unfavorable circumstances,
at most one per cent. of the anilin. By distillation of the raw product obtained, a
pure anilin can at once be obtained.
The above described new process therefore enables the calcium sulphide residues
to be worked in a profitable manner, and at the same time anilin of great purity and
excellent yield is obtained.
In place of the nitrobenzol, nitrotoluols, nitrobenzaldehyde can be subjected to
the reaction.
The calcium sulphide can be replaced by barium or strontium sulphides.
Example: 4 parts of nitrobenzol are heated for from 4 to 8 hours together with

page_text: 6 parts of calcium sulphide and 5 to 10 parts of water, under continual stirring,
either with a reflux cooler or in closed vessels; the anilin produced is blown off by
means of steam and is purified by distillation.
Having now particularly described and ascertained the nature of my said inven-
ion and in what manner the same is to be performed I declare that what I
claim is :-
1. The process for utilizing the sulphides and sulphydrates of alkaline earths by
converting the same by means of nitro compounds into the corresponding free bases
and thio sulphates or thio sulphates only, substantially as herein described.
2. Process for utilizing calcium sulphide by converting it by means of nitro
compounds of the aromatic series into caustic lime and calcium thiosulphate, or by
first converting it according to known methods into caustic lime and calcium
sulphydrate, and then employing the latter for treatment with the nitro compounds
for obtaining calcium thiosulphate, substantially as described.
3. Process for the production of anilin toluidine, or amidobenzaldehydes,
consisting in reducing the corresponding nitro compounds by means of the sulphides
or sulphydrates of the alkaline earths, substantially as described.
Dated this 2nd day of September 1895.
ABEL & IMRAY,
Agents for the Applicant.