The Manufacture of New Colouring Matters of the Series of the Indulines by the Action of the Diamido-dialkyl Thioureas on the Aromatic Amines.
Year: 1892

page_text: Date of Applicati
Complete Specification Left, 11th Nov., 1892-Accepted, 31st Dec., 1892
COMPLETE SPECIFICATION.
The Manufacture of New Colouring Matters of the Series of the
Indulines by the Action of the Diamido-dialkyl Thioureas on
the Aromatic Amines.
I, JOSEPH ROHNER, of Basel, Switzerland, 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 present invention is based on the observation that on heating the hydro-
chlorates of the diamido-dialkyl thio ureas (diamido-dialkyl carbamines) with
aromatic amines red and grey blue colouring matters are obtained. If the said
derivatives of urea are fused with a monamine, colouring matters are obtained,
which are soluble in alcohol and can easily be transformed by the ordinary means
of sulphonation into sulpho conjugate products of very great value; but if the same
derivatives of urea or carbamines are fused with a diamine, colouring matters soluble
in water are directly obtained. By their properties these colouring matters take
position in the series of indulines and rose indulines. Hitherto I have obtained
advantageous practical results by the application on the one side of diamido-
diphenylthiourea, or diamido-dinaphthylthiourea, and on the other side of aniline,
paraphenylenediamine, benzidine or tolidine.
In employing hydrochlorate of diamido-diphenyl-thiourea (hydrochlorate of
diamido-diphenyl thio-carbamine) and paraphenylene diamine, I obtain, for
instance, a grey blue colouring matter, which in the state of hydrochlorate is
soluble in water and presents the dyeing properties of the indulines directly soluble
in water.
If I heat the hydrochlorate salt of diamido-dinaphthyl thiourea with aniline, I
obtain a colouring matter which is readily dissolved in dilute hydrochloric acid
giving a red violet solution; with concentrated sulphuric acid, the same colouring
matter gives a green solution, and with fuming sulphuric acid, it becomes trans-
formed into various sulphoconjugate acids according to the temperature and the
degree of concentration of the acid.
The following examples will sufficiently explain my invention.
I. PREPARATION OF THE DIAMIDODIALKYLTHIOUREAS.
In order to prepare, for instance, the diamidodiphenylthiourea (diamidodiphenyl
30 carbamine) I proceed as follows :-
parts amidoazobenzol
alcohol
دو
20
200
5.6
caustic potash
"
3 to 4 "
sulphide of carbon
35 are heated for one to two hours in a vessel having a reflux cooler. Thus is formed
the aze-benzol thiourea
[Price Ed.]
CH,N=NCH,NH CS NHCH.N = NCH¸.

page_text: The alcohol is driven off by distillation and the residue is then exhausted with
water which removes from it sulphide of potassium and a small quantity of
xantogenate of potash.
CS,KOC₂H.
If the azobenzolthiourea obtained is subjected to the action of a reducing agent
it breaks up into aniline and diamidodiphenyl thiourea. This reduction is best
effected with hydrochloric acid and iron shavings, and from the filtered liquor the
diamidodiphenyl thiourea is precipitated in the form of a hydrochlorate by excess
of hydrochloric acid.
During the operation of the reduction the temperature should not rise
above 30° C. otherwise hydro sulphuric acid would be produced. The reduction
might also be effected by zinc powder in a neutral solution heated to boiling; this
mode of operating presents the advantage that the aniline can easily be
recovered.
Instead of amidoazobenzol there might be employed in the above example
paranitraniline. The dinitrothiourea obtained would be reduced in the same
manner.
The diamidodiphenyl thio urea is soluble with great difficulty in water. Its
salts with mineral acids are easily soluble.
The diamidonaphthylthiourea can be obtained in the same manner by sub-
stituting, for example, for the amidoazobenzol, benzol azo-a-naphthylamine. From
its aqueous solution it crystallises in brilliant leaflets which rapidly assume a deep
shade or become black in colour.

page_text: with ammonia. By cooling is obtained in crystallised condition the ammonia salt
of the sulphonic acid formed.
After drying, this salt presents itself in form of a deep red powder, and it dyes
wool in an acid bath a red tint inclining to violet.
Instead of sulphuric acid, similar sulphonating agents may be employed, such for
example as sulphuric monochlorhydrine.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. The manufacture of diamidodialkyl thio ureas by reduction of corresponding
dinitrated compounds, or of azobenzol thio urea, benzolazonaphthaline thiourea or
the like.
2. The manufacture of grey blue colouring matters by heating diamidodiphenyl-
thiourea with paraphenylenediamine, benzidine or tolidine.
3. The manufacture of a red colouring matter soluble in alcohol by heating
diamidodinaphthyl thio urea with anilines.
4. The transformation of the colouring matter referred to in the preceding claim
into sulphonate soluble in water by treating it with fuming sulphuric acid or like
sulphonating agent.
5. The colouring matters produced by the several processes claimed in Claims 2,
3 and 4.
Dated this 11th day of November 1892.
AT
T
Agents for the Applicant.