Improved Extract of Logwood and Method of Obtaining the same.
Year: 1898

page_text: Date of Application, 1st Jan., 1898-Accepted, 19th Mar., 1898
COMPLETE SPECIFICATION.
Improved Extract of Logwood and Method of Obtaining the same.
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 Francis Emile Bucher, Ph. D., a citizen of the
Republic of Switzerland, residing in Spanish Town, in the Parish of St. Catherine,
County of Middlesex, Jamaica, British West Indies, Chemical Manufacturer), and
in what manner the same is to be performed to be particularly described and
ascertained in and by the following statement:-
It is known that in many applications of logwood or extracts from logwood
haematein C16H12O6 gives much superior results to haematoxylin C16 H14 06
It has been held that in order to obtain the coloured pigments characteristic of
logwood a process of oxidation must invariably take place, either during the
dyeing process, in which case the oxygen would as a rule be supplied by the
mordant, or previously to the dyeing process, where haematoxylin is converted
into haematein. In the case of logwood chips an oxidation is attained by the well
known process of curing or ageing. This process is tedious, cumbersome and often
wasteful. Several patents have been granted for chemical processes devised for
oxidizing liquors or extracts from logwood. Amongst the chemical agents used in
such processes were solution of bleaching powder, hypochlorous acid, chloric acid,
chlorates or nitrates of the alkalies and alkaline earths, and chlorine as a gas or in
solution.
This invention effects in a practical manner the conversion of haematoxylin into
haemateïn more smoothly than is possible by any other known practical means.
My foreign correspondent has found that the oxides of nitrogen richer in oxygen
than deutoxide of nitrogen NO, when allowed to react upon haematoxylin, convert
it into haematein and he has found that 50 grams peroxide of nitrogen, NO₂, or
80 grams trioxide of nitrogen, N₂O3, conducted slowly, in a vaporized form, into a
solution of 100 grams haematoxylin in 2 litres water, at ordinary temperature,
convert the haematoxylin effectively into haemateïn.
In practice my foreign correspondent uses preferably peroxide of nitrogen, NO,,
in a gaseous form, as it is readily obtained either as such or by the reaction of air
upon either deutoxide or nitrogen NO or trioxide of nitrogen N₂O.
Before applying this process to a liquor or extract from logwood the proportion
of the peroxide of nitrogen to the liquor or extract that is required to obtain the
desired proportion of haematein in the final liquor or extract is determined by a
preliminary trial. This quantity of peroxide will naturally depend upon the
quantity of haematoxylin contained in the liquor or extract to be treated, and also
upon the proportion of haemateïn that may be desired.
The following process gives in practice an extract of logwood, whose colouring
principal consists almost entirely of haemateïn.
The gases, mainly vapour from nitrogen trioxide, and peroxide of nitrogen
obtained by the decomposition of 70 lbs. nitric acid of 80 degrees Twaddell by
means of 20 lbs. sugar, at 80 degrees Centigrade, are brought into contact with a
powerful current of air and thus diluted, are led into 1000 lbs. extract, of
20 degrees Twaddell, obtained from non-cured logwood, the extract being kept at
837
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page_text: ordinary temperature. This current, which converts the vapour from trioxide of
nitrogen into peroxide, besides beneficially diluting the reacting gas, namely
peroxide of nitrogen, agitates the extract, thereby causing the peroxide to react
evenly and gradually upon the extract.
Most of the haematein formed, it being sparely soluble, precipitates.
result of the reaction nitric acid is formed also.
As a
To neutralise it, 50 lbs. of soda ash dissolved in water is added. The product may
then be used as such or concentrated.
I describe a modification of this process as follows:-
The product of the reaction may be allowed to settle 12 hours, when the clear
and weak acid liquor is run off. This liquor is neutralised by itself and
concentrated. The sediment, which contains most of the haemateïn formed is
washed with water and dried. The commercial haemateïn thus produced is of
intense dyeing power.
I do not limit myself to any particular mode of production of the oxides of
nitrogen, nor to the given proportion of them to the extract to be treated, nor to the
given concentration of the extract; the mode of production of oxides of nitrogen,
the proportion and the concentration hereinbefore mentioned merely serve as an
example to enable a person skilled in the art of chemical manufacture to carry out
this invention.
Nor is the temperature at which the operation is carried on of great importance.
Keeping the extract at ordinary temperature during the reaction answers the
purpose very well.
The principle of this invention for which I claim protection is the conversion of
haematoxylin into haemateïn by the oxides of nitrogen richer in oxygen than
deutoxide of nitrogen, or a mixture of them.
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 improvement in the treatment of liquors, or extracts, from logwood,
consisting in subjecting such liquors, or extracts, to the action of the oxides of
nitrogen richer in oxygen than deutoxide of nitrogen, substantially as described.
2. As a new article of manufacture, the herein described liquor, or extract, of
logwood obtained by subjecting logwood liquor, or extracts, to the action of oxides
of nitrogen richer in oxygen than is deutoxide of nitrogen, substantially as
described.
Dated this 1st day of January 1898.