The Manufacture and Production of Indigo-white Compounds.
Year: 1899

page_text: PROVISIONAL SPECIFICATION.
The Manufacture and Production of Indigo-white Compounds.
I, JAMES YATE JOHNSON, of 47, Lincoln's Inn Fields, in the County of
London, Gentleman, do hereby declare the nature of this invention (which has
been communicated to me from abroad by the Badische Anilin & Soda Fabrik
of Ludwigshafen-on-Rhine, in the German Empire) to be as follows:-
Indigo is, as a rule, used in dyeing by first reducing it to a leuco-compound
which is solubie in alkaline water and which is known as indigo-white. Indigo-
white possesses the quality of combining very readily with oxygen so that, in
contact with air, it becomes reconverted into indigo. This instability of indigo-
white in the presence of air has hitherto constituted a difficulty in bringing it
into commerce so that indigo-dyes, as a rule, have been compelled to themselves
reduce the indigo that they employ to indigo-white.
The present invention consists in the production of new compounds of indigo-
white which are stable in the presence of air but which can be readily converted
into indigo-white or its salts. The new compounds can consequently be used for
the production of indigo on the fibre and are particularly suited for use in
printing.
The new compounds are obtained by treating indigo-white, under suitable con-
ditions, with formaldehyde, the chlorides of carbonic acid, for example phosgene
or the esters of chloro-carbonic acid.
When using formaldehyde the treatment is to be effected in neutral
solution, or suspension, in order that the desired product may be
smoothly obtained. If the treatment be effected in an acid solution, a mixture
is obtained containing amorphous product readily soluble in alcohol and a
crystallised portion which it is difficult to dissolve in alcohol. If an alkaline
solution of indigo-white be treated with formaldehyde, and then precipitated
with excess of hydrochloric acid, the product obtained is a mixture, and the
desired new product can only be isolated from this mixture by suitable treatment
in small quantities.
The following examples will serve to further illustrate the nature of the inven-
tion but it is not confined to these examples. The parts are by weight.
EXAMPLE 1.
NEW PRODUCT FROM INDIGO-WHITE AND FORMALDEHYDE.
Suspend about twenty six and a half parts of indigo-white in two hundred
parts of water and add about thirty parts of a solution of formaldehyde. contain-
Suspend about twenty six and a half parts of indigo-white in two hundred
parts of water and add about thirty parts of a solution of formaldehyde. contain-
ing about forty per cent. formaldehyde. Agitate the mixture thoroughly, at
ordinary temperature, until all the indigo-white has disappeared. The new com-
pound separates out as a greenish powder. Collect by filtering, wash with water,
and dry. The drying may be effected without exclusion of air, in the usual way.
The new compound is, with difficulty, soluble in water and cold alcohol, almost

page_text: can be used, for instance, alcohol.
EXAMPLE 2.
NEW PRODUCT FROM INDIGO-WHITE AND PHOSGENE.
Dissolve about fifty parts of indigo-white in about five hundred parts of acetone,
and add about fifty parts of caustic soda lye containing about 35 per cent. of
Na OH. Keep the mixture cool by means of ice and, whilst agitating, pass in
phosgene gas, until a test portion of the solution, after being rendered alkaline,
no longer assumes a blue colour on filtering paper. The greater part of the
reaction product separates out and is collected by filtration. To obtain the
remainder, neutralise with solid carbonate of soda and distil off the acetone.
The reaction can be effected when the indigo-white is dissolved in alkaline
water instead of in acetone. In both cases the product obtained is insoluble,
or nearly so, in the ordinary solvents, but is somewhat soluble in boiling acetone.
On warming with caustic soda solution it yields an indigo vat.
EXAMPLE 3.
NEW PRODUCTS FROM INDIGO-WHITE AND THE ETHYL ESTER OF CHLORO-CARBONIC
ACID.
Dissolve about fifty parts of indigo-white in about five hundred parts of acetone
and about forty five parts of caustic soda lye containing about 35 per cent. Na OH.
To this mixture add in small quantities at a time, forty five parts of the ethyl
ester of chlorocarbonic acid. Shake the mixture thoroughly during this addition.
The new product separates out in part. Collect, by filtering, and dry. It is
colourless when pure and dissolves in the usual solvents, particularly on heating.
A somewhat different product remains dissolved in the mother-liquor; to obtain
it distil off the acetone. A residue, which is usually reddish, results, recrystallize
this, say from alcohol, and the desired new product is obtained as crystals, which
are colourless, or nearly so and are readily soluble in nearly all solvents.
Both the products obtained according to this example, on heating with caustic
soda solution, yield an indigo vat.
Instead of the ethyl ester of chloro-carbonic acid, other esters may be used,
for instance the methyl ester. If, instead of using the said ethyl ester, the indigo-
white sodium compound be treated with phosgene in alcoholic solution (which
will yield the ethyl ester of chloro-carbonic acid) similar results are obtained.
Dated this 23rd day of November 1899.
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, London, W
Agents.
The Manufacture and Production of indigo-white Compounds.
I, JAMES YATE JOHNSON, of 47, Lincoln's Inn Fields, in the County
London, Gentleman, do hereby declare the nature of this invention (which h
(

page_text: been communicated to me from abroad by the Badische Anilin & Soda Fabrik
of Ludwigshafen-on-Rhine, in the German Empire) and in what manner the
same is to be performed to be particularly described and ascertained in and by
the following statement:-
Indigo is, as a rule, used in dyeing by first reducing it to a leuco compound
which is soluble in alkaline water and which is known as indigo-white. Indigo-
white possesses the quality of combining very readily with oxygen so that, in
contact with air, it becomes reconverted into indigo. "This instability of indigo-
white in the presence of air has hitherto constituted a difficulty in bringing it
into commerce so that indigo dyers, as a rule, have been compelled to themselves
reduce the indigo that they employ to indigo-white.
The present invention consists in the production of new compounds of indigo-
white which are stable in the presence of air but which can be readily converted
into indigo-white or its salts. The new compounds can consequently be used for
the production of indigo on the fibre and are particularly suited for use in
printing.
The new compounds are obtained by treating indigo-white, under suitable con-
ditions, with formaldehyde, the chlorides of carbonic acid, for example, phosgene
or the esters of chloro-carbonic acid.
When using formaldehyde the treatment, according to this invention, is to be
effected in neutral solution, or suspension, in order that the desired product may be
smoothly obtained. If the treatment be effected in acid solution, a mixture
is obtained containing amorphous product readily soluble in alcohol and a
crystallised portion which it is difficult to dissolve in alcohol. If an alkaline
solution of indigo-white be treated with formaldehyde, and then precipitated
with excess of hydrochloric acid, the product obtained is a mixture, and the
desired new product can only be isolated from this mixture in small quantities
by suitable treatment. When using the chlorides of carbonic acid, these are
caused to act on the indigo-white in the form of its salts, for instance, the sodium
salt resulting from the mixture of indigo-white with caustic soda lye.
The following examples will serve to further illustrate the nature of the inven-
tion and the manner in which it may be carried into practical effect but it is not
confined to these examples. The parts are by weight.
EXAMPLE 1.
Suspend about twenty six and a half parts of indigo-white in two hundred
parts of water, and add about thirty parts of a solution of formaldehyde, contain-
ing about forty per cent. formaldehyde. Agitate the mixture thoroughly, at
ordinary temperature, until all the indigo-white has disappeared. The new com-
pound separates out as a greenish powder. Collect by filtering, wash with water,
and dry. The drying may be effected without exclusion of air, in the usual way.
The new compound is, with difficulty, soluble in water and cold alcohol, almost
insoluble in ether and benzene, but readily soluble in acetone and hot glacial
acetic acid. It can be recrystallised from hot alcohol yielding greenish-yellow
foliate crystals. Upon treatment with caustic alkalies, the carbonates of the
alkalies or with the alkaline earths, at ordinary temperature, or on boiling with
water. the new compound is reconverted into indigo-white, or its salts.
Instead of suspending the indigo-white in water, other diluents, or solvents,
can be used, for instance, alcohol.

page_text: ´and add about fifty parts of caustic soda lye containing about 35 per cent, of
Na OH. Keep the mixture cool by means of ice and, whilst agitating, pass in
phosgene gas, until a test portion of the solution, after being rendered alkaline,
no loner assumes a blue colour on filtering paper. The greater part of the
reaction product separates out and is collected by filtration. To obtain the
remainder, neutralise with solid carbonate of soda and distil off the acetone.
The reaction can be effected when the indigo-white is dissolved in alkaline
water instead of in acetone. In both cases the product obtained is insoluble,
or nearly so, in the ordinary solvents, but is somewhat soluble in boiling acetone.
On warming with caustic soda solution it yields an indigo vat.
EXAMPLE 3.
NEW PRODUCTS FROM INDIGO-WHITE AND THE ETHYL ESTER OF CHLORO-CARBONIC
ACID.
Dissolve about fifty parts of indigo-white in about five hundred parts of acetone
and about forty five parts of caustic soda lye containing about 35 per cent. Na OH.
To this mixture add in small quantities at a time, forty five parts of the ethyl
ester of chloro-carbonic acid. Shake the mixture thoroughly during this addition.
The new product separates out in part. Collect, by filtering, and dry. It is
colourless when pure and dissolves in the usual solvents, particularly on heating.
A somewhat different product remains dissolved in the mother-liquor; to obtain
it distil off the acetone. A residue, which is usually reddish, results, recrystallize
this, say from alcohol, and the desired new product is obtained as crystals, which
are colourless, or nearly so and are readily soluble in nearly all solvents.
Both the products obtained according to this example, on heating with caustic
soda solution, yield an indigo vat.
Instead of the ethyl ester of chloro-carbonic acid, other esters may be used,
for instance, the methyl esters. If, instead of using the said ethyl ester, the indigo-
white sodium compound be treated with phosgene in alcoholic solution (which
will yield the ethyl ester of chloro-carbonic acid) similar results are obtained.
Having now particularly described and ascertained the nature of this
invention, and in what manner the same is to be performed I declare that what
1 claim is:
1. The manufacture of an indigo-white compound which is stable in the presence
of air by treating indigo-white in neutral solution, or suspension, with formalde-
hyde, substantially as herein before described.
2. The manufacture of indigo-white compounds by treating indigo-white in
the form of a salt with a chloride of carbonic acid, such as phosgene, or an ester
of chloro-carbonic acid substantially as hereinbefore described.
3. The manufacture of indigo-white compounds substantially as described in
the foregoing several examples.
4. As new articles of manufacture the indigo-white compounds such as can
be obtained substantially as herein before described and claimed.
Dated this 20th day of August 1900
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, London, W.C,
Agents.