Manufacture of Blue Colouring Matters.
Year: 1893

page_text: Date of Application, 16th Jan., 1893
Complete Specification Left, 11th Oct., 1893-Accepted, 11th Nov., 1893
:
PROVISIONAL SPECIFICATION.
[Communicated from abroad by THE SOCIETY OF CHEMICAL Industry in
BASLE, Basle, Switzerland.]
Manufacture of Blue Colouring Matters.
I, OLIVER IMRAY of No. 28 Southampton Buildings, in the County of London,
Chartered Patent Agent, do hereby declare the nature of this invention to-be as
follows:-
It is well known that by condensation of dimethylaniline with dichlorbenz-
aldehyde (described by R. Gnehm Berl. Ber. XVII p. 752) and subsequent
oxidation, a blue-green colouring matter of the malachite green series is
obtained.
My correspondents have now discovered that by employing the monoalkylised
derivatives of o-toluidine instead of dimethylaniline, blue basic dye stuffs possessing
tints of grent beauty varying from the most blueish green to the most greenish blue
hitherto known, are formed, which dye on wool and silk as well as on cotton
mordanted with tannin and tartar emetic.
II. OXYDATION.
The leuco-compounds may be converted into colouring matters according to the
same process as known for the products of the malachite green series, for
example:
30 parts of symmetrical-dimethyl-diamido-ortho-ditolyl-dichlor-
phenyl methane are dissolved in
40 parts of muriatic acid and

page_text: The colouring matter is immediately formed and precipitated in the usual way in
the form of the double salt of zinc-chloride, and purified by re-dissolving in
water.
It is a glittering powder which has a bronze lustre, with difficulty soluble in
cold water, easily soluble in boiling water; these solutions coagulate after
cooling.
The new dye stuff produces intense greenish-blue tints on wool, silk and cotton
(treated with tannin and tartar emetic).
In an analogous manner a colouring matter with similar properties results from
symmetrical diethyl-diamido-ortho-ditolyl-dichlor-phenyl-methane.
Dated this 16th day of January 1893.
ABEL & IMKAY,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Manufacture of Blue Colouring Matters.
I, OLIVER IMRAY, of No. 28 Southampton Buildings, in the County of London,
Chartered 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 :-
It is well known that by condensation of dimethylaniline with dichlorbenz-
aldehyde (described by R. Gnehm Berl. Ber. XVII p. 752) and subsequent
oxidation, a blue green colouring matter of the malachite green series is
obtained.
My correspondents have now discovered that by employing the monoalkylised
derivatives of o-toluidine instead of dimethylaniline, blue basic dye stuffs possessing
tints of great beauty varying from the most bluish green to the most greenish blue
hitherto known, are formed, which dye on wool and silk as well as on cotton
mordanted with tannin and tartar emetic.
The monoalkyl-orthotoluidine besides being used alone may be used in admixture
with dimethyl-aniline for condensation with dichlorbenzaldehyde to form coloring
matters having shades between the blues obtained by condensing mono-alkyl-ortho-
toluidine and the greens obtained by condensing dimethylaniline.
The production of symmetrical dimethyl-diamido-ortho-ditolyl-dichlorphenyl-
'methane may be effected, for example, as follows (the parts are by weight)
60 parts of mono-methyl-ortho-toluidine
60
وو
44
."
"
"
25
"
dichlorbenzaldehyde
alcohol and
sulphuric acid
are heated during 24 hours in the water bath in an enamelled vessel.
The mass of the reaction is supersaturated with soda lye after which the
unaffected oils are expelled by means of water vapour and the remaining leuco base
is washed and dried.
The production of symmetrical-diethyl-diamido-ortho ditolyl-dichlorphenyl-
methane may be effected in an analogous manner by substituting for mono-methyl-
ortho-toluidine the equivalent quantity of mono-ethyl-ortho-toluidine.
Instead of sulphuric acid, any other dehydrating agent, such as muriatic acid,
chloride of zinc &c. may be used.
The colourless leuco compounds thus obtained are compact and dissolve easily in
ether, benzene, warm alcohol and in dilute mineral acids.

page_text: II. OXIDATION.
The leuco compounds may be converted into colouring matters according to the
same process as is known for the products of the malachite green series, for
example:
30 parts of symmetrical-limethyl-diamido-ortho-ditolyl-dichlor-
phenyl-methane are dissolved in
40 parts of muriatic acid and
1500-
"
water.
"
To this solution the equivalent quantity of peroxide of lead, in paste, or another
suitable oxidising agent, is added.
The colouring matter is immediately formed and precipitated in the usual way in
the form of the double salt of zinc chloride, and purified by re-dissolving in
water.
It is a glittering powder which has bronze lustre, with difficulty soluble in
cold water, easily soluble in boiling water; these solutions coagulate after
cooling.
The new dye stuff produces intense greenish blue tints on wool, silk and cotton
(treated with tannin and tartar emetic).
In an analogous manner a colouring matter with similar properties results from
symmetrical diethyl-diamido-ortho-ditolyl-dichlor-phenyl-methane.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. The production of symmetrical dimethyl-diamido-ortho-ditolyl-dichlor-phenyl-
methane and of symmetrical diethyl-diamido-ortho-ditolyl-dichlor-phenyl-methane
by condensation of mono-alkylised ortho-toluidine, namely monomethyl and mono-
ethyl-ortho-toluidine with dichlorbenzaldehyde.
2. The manufacture of blue colouring matters by oxidising the leuco bases
referred to in the preceding claim with peroxide of lead, peroxide of manganese or
analogous agents, substantially as described.
3. As new products the leuco bases produced as set forth in the first claim.
4. As new products the blue basic dye stuffs manufactured as set forth in the
second claim.
Dated this 3rd day of October 1893.
ABEL & IMRAY,
Agents for the Applicant.