Improvements in the Manufacture and Production of Anthraquinone Derivatives
Year: 1892

page_text: Date of Application, 7th July, 1892
Complete Specification Left, 5th Apr., 1893-Accepted, 13th May, 1893
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture and Production of Anthraquinone
Derivatives.
I, BENJAMIN WILLCOX of 47 Lincolns Inn Fields, in the County of Middlesex
Patent Agent do hereby declare the nature of this invention (which has been
communicated to me from abroad by The Farbenfabriken vormals Friedrich
Bayer & Co. of Elberfeld in the Empire of Germany) to be as follows:-
In the Specifications of Letters Patent No. 12715 dated 13th August 1890,
No. 17712 dated 4th November 1890, No. 18729 dated 19th November 1890,
No. 1883 dated 2nd February 1891 and No. 4871 dated 18th March 1891 and in
the Specifications of applications for Letters Patent No. 13677 dated
13th August 1891 No. 21717 dated 11th December 1891 and No. 1657 dated
27th January 1892 my foreign correspondents have described that by a suitable
oxidation of anthraquinone and its derivatives polyoxyanthraquinones or substi-
tution products thereof are formed which are in general termed alizarinecyanines.
As oxidising agents sulphuric acid anhydride, manganese dioxide, and the like
have been employed.
My foreign correspondents have now found that anthraquinone and its derivatives
when dissolved in concentrated sulphuric acid can also be oxidised into so called
alizarinecyanines by means of the electric current.
From anthraquinone, alizarin, purpurine and flavopurpurine, hexaoxyanthra-
quinone, described in the Specification of application for Letters Patent
No. 13677 dated 13th August 1891 is obtained in this manner, whilst anthra-
purpurine yields by the same process alizarin hexacyanine described in the
Specification of Letters Patent No. 4871 dated 18th March 1891 and alizarin
bordeaux is at first converted into alizarinpentacyanine described likewise in the
last named Specification and then into the aforesaid hexaoxyanthraquinone.
My foreign correspondents have found that although sulphuric acid at
66 degrees Baumé is sufficient for the oxidation of alizarin bordeaux the same process
is carried out more advantageously when employing anthraquinone, alizarin
purpurine, flavopurpurine and anthrapurpurine, by means of a moderately fuming
sulphuric acid. In the latter case the polyoxyanthraquinones are sulphurized at the
same time but the polyoxyanthraquinones (alizarin cyanines) themselves can be
obtained therefrom with great readiness by again separating the sulpho groups in
the known manner.
My foreign correspondents have ascertained by their investigations that it is
profitable to effect the oxidation at not too high a temperature for example at from
about 20 to 50 degrees centigrade.
The following is given as an example for the production of hexaoxyanthraquinone
from flavopurpurine.
The electric current is allowed to pass through a solution of 1 part by weight of
flavopurpurine in 10 parts by weight of fuming sulphuric acid containing 20 per cent.
of anhydride the solution being in a vessel provided with an apparatus for cooling.
The negative pole (cathode) is in the fuming sulphuric acid and is separated from
the positive electrode (anode) by a diaphragm. The intensity of the electric
current is by preference six amperes for one square decimeter. When unaltered
flavopurpurine is no longer distinguishable, the reaction is complete. The liquid is
then poured into water and after filtering the dye-stuff sulpho-acid is precipitated
by means of common salt or potassium chlorid and is filtered off pressed and
dried.
:
:

page_text: In order to convert the said sulpho acid into the colouring matter itself viz.
hexaoxyanthraquinone 1 part by weight, of the said sulpho acid is heated with
10 parts by weight of sulphuric acid at 60 degrees Baumé for some hours at
a temperature from about 150 to 170 degrees centigrade. The liquid thus obtained
is poured into water and the dyestuff precipitated is filtered off.
In an analogous manner the anthraquinone and the other derivatives thereof are
oxidised by means of the electric current. If oleum be employed as a solvent the
sulpho products formed are converted into the unsulphurised cyanine derivatives by
splitting off the sulpho group in the manner hereinbefore described.
Dated this 7th day of July 1892.
J. H. JOHNSON & Co.,
47, Lincoln's Inn Fields, London, W.C., Agents.
COMPLETE SPECIFICATION.
Improvements in the Manufacture and Production of Anthraquinone
Derivatives.
I BENJAMIN WILLCOX of 47 Lincoln's Inn Fields in the County of Middlesex,
Patent Agent do hereby declare the nature of this invention (which has been
communicated to me from abroad by Farbenfabriken vorm. Friedr. Bayer & Co.
of Elberfeld in the Empire of Germany) and in what manner the same is to be
performed to be particularly described and ascertained in and by the following
statement:―
In the Specifications of Letters Patent No. 12715 dated 13th August 1890,
No. 17712 dated 4th November 1890, No. 18729 dated 19th November 1890,
No. 1883 dated 2nd February 1891 and No. 4871 dated 18th March 1891 and in
the Specifications of Letters Patent No. 13677 dated 13th August 1891, No. 21717
dated 11th December 1891 and No. 1657 dated 27th January 1892 processes are
described whereby anthraquinone and its derivatives are converted by means of
suitable oxidising agents into polyoxyanthraquinones or substitution products
thereof generally termed alizarin cyanines. Sulphuric anhydride,, manganese
dioxide and the like have been employed as oxidising agents.
My foreign correspondents have now found that when dissolved in concentrated
sulphuric acid anthraquinone and its derivatives can be oxidised and converted
into so called alizarin cyanines also by means of the electric current.
Operating in this manner the hexaoxyanthraquinone described in the Specifica-
tion of Letters Patent No. 13677 dated 13th August 1891 is obtained from
authraquinone, alizarin, purpurin and flavo-purpurin, whilst anthrapurpurin when
submitted to the same process yields the alizarin bexacyanine described in the
Specification of Letters Patent No. 4871 dated 18th March 1891 and alizarin
bordeaux is at first converted into alizarin pentacyanine likewise described in the
last named Specification and then into the aforesaid hexaoxyanthraquinone.
My foreign correspondents have found, that although sulphuric acid (66 degrees
Baumé) suffices for the oxidation of alizarin bordeaux the process is carried out
more advantageously in the case of anthraquinone, alizarin, purpurin, flavopurpurin
and anthrapurpurin by means of a moderately fuming sulphuric acid. In the
latter case the resulting polyoxyanthraquinones become sulphonated but the said
polyoxyanthraquinones (alizarin cyanines) can be readily obtained from the
sulphonated products by again splitting off the sulpho groups in a suitable
manner.
My foreign correspondents have ascertained that it is profitable to effect
the oxidation at not too high a temperature for example at from about 20 to
50 degrees centigrade.
The following is given as an example of one method of producing hexaoxyanthra-
quinone from flavopurpurin.
The electric current is allowed to flow through a solution of 1 part, by weight,

page_text: of flavopurpurin in 10 parts, by weight, of fuming sulphuric acid containing
20 per cent. of anhydride the solution being contained in a vessel provided with a
cooling arrangement. The negative pole (cathode) is in the fuming sulphuric acid
and is separated from the positive electrode (anode) by a diaphragm. The
intensity of the electric current is by preference six ampères per square decimeter.
When unaltered flavopurpurin is no longer distinguishable, the action is complete.
The liquid is then poured into water and the sulphonated dye-stuff is precipitated
from the filtered solution by means of common salt or potassium chloride and is
filtered off, pressed and dried.
In order to convert the said sulpho acid into the unsulphonated colouring-matter
or bexaoxyanthraquinone 1 part, by weight, of the said sulpho acid is heated with
10 parts by weight, of sulphuric acid (60 degrees Baumé) during several hours at
a temperature from about 150 to 170 degrees centrigrade. The liquid thus
obtained is poured into water and the precipitated dye-stuff is filtered off.
Anthraquinone and the other derivatives thereof are oxidised in an analogous
manner by means of the electric current. If fuming acid be employed as a solvent,
sulphonated products are formed which can be converted into the unsulphonated
cyanine derivatives by splitting off the sulpho group in the manner hereinbefore
described.
The production of the other alizarin cyanine dye-stuffs or the sulpho acids
thereof can be effected in a manner similar to that described in the above example,
but I do not limit myself to the directions given in the said example, as the process
can be varied without departing from the nature of this invention which relates in
general to the production of alizarin cyanine dye-stuffs or sulpho acids thereof by.
means of the electric current.
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 alizarin cyanine dye-stuffs or sulpho acids thereof from
anthraquinone or its derivatives by an oxidation process which is effected by means
of the electric current.
2. The process of producing alizarin cyanine dye-stuffs, by allowing the electric
current to flow through solutions of anthraquinone or its derivatives in concentrated
sulphuric acid or in fuming sulphuric acid and subsequently splitting off the sulpho
group in case sulphonation has taken place at the same time that oxydation has
been effected by the electric current.
3. The conversion of anthraquinone, alizarin, purpurin or flavopurpurin into
hexaoxyanthraquinone by subjecting the solutions of the latter in fuming sulphuric
acid to the action of the electric current and subsequently splitting off the sulpho
groups from the sulphonated alizarincyanine dye stuffs thus produced.
4. The transformation of alizarin bordeaux into alizarin pentacyanine or hexa-
oxyanthraquinone by subjecting its solution in concentrated sulphuric acid to the
action of the electric current.
5. The process for producing alizarin hexacyanine by allowing the electric
current to pass through a solution of anthra purpurin in fuming sulphuric acid and
subsequently splitting off the sulpho group from the resulting sulpho acid of
alizarinhexacyanine.
B. WILLCOX.