Improvements in the Separation and Purification of Colouring Matter from Crude Cotton Seed Oil.
Year: 1895

page_text: Date of Application, 20th Dec., 1895
Complete Specification Left, 21st Sept., 1896-Accepted, 12th Dec., 1896
Improvements in the Separation and Purification of Colouring
Matter from Crude Cotton Seed Oil.
We EDGAR SIDDONS WILSON of "Arthog" Goddington Road, Strood, in the
County of Kent, Chemist, and EBENEZER STEWART of 4 Queen Victoria Street
in the City of London, Merchant, do hereby declare the nature of this invention to
be as follows:-
In refining crude cotton seed oil by alkaline solutions, such for example as
caustic soda or a mono-carbonate of soda with or without the addition of a soluble
sulphite, a colouring matter is removed from the oil which has not hitherto been
found of much value owing to its admixture with fatty matter and other impurities.
We have found that by suitable treatment, impurities can be removed from the
colouring matter, and the latter rendered more suitable for use.
In carrying out our invention we take the alkaline liquor separated from the oil
and containing the said colouring matter and impurities, and treat it by the process
known to chemists as "fractional precipitation" using for this purpose certain
earthy salts such as the chlorides of magnesium or calcium, sulphate of magnesia,
or any of the salts of metallic bases, which with the fatty acids removed from the
oil by the said alkaline liquor produce insoluble or not easily soluble soaps. The
fatty acids, resinous matter and other impurities are by this means wholly or partly
got rid of, and to the residual liquor which contains the colouring matter is
added hydrochloric or sulphuric acid or any acid which will combine with the
alkali or decompose alkaline carbonate or soluble sulphite and precipitate the
said colouring matter. The colouring matter precipitated as B flocculent
precipitate is collected for use preferably in a pasty condition.
As an example of the application of our invention we give the following:
Two thousand two hundred gallons of crude cotton seed oil are agitated in a
suitable tank with six hundred gallons of a solution of soda crystals containing
from one quarter to one half a pound of crystals to the gallon. We have found
that the colouring matter undergoes deterioration during this process if the tem-
perature is allowed to reach the boiling point (212° Fahrenheit) and we therefore
prefer to use a refining solution of the above or other convenient strength at a
temperature of about 120° to 130°. After the oil and alkaline liquor have been
kept in agitation for the time necessary to remove the colouring matter, the
contents of the tank are allowed to separate by subsidence or are made to separate
by any known methods and the liquor which is of a deep brown colour is drawn
off. The brown liquor is then mixed with a solution of magnesium or calcium
chloride, so that from one half to one part, by weight, of the salt is added to one
hundred parts by weight of the liquor. The mixture of liquor and salt solution
is then raised to the boiling point and kept boiling till the separation of the dark
insoluble or not easily soluble mixture of soap and other impurities is complete.
The hot liquor which now contains the improved colouring matter is then allowed
to remain at rest and is drawn off, or if necessary, filtered or separated by any known
method from the impure soap. The purified colouring matter is precipitated by
dilute hydrochloric or sulphuric, or any suitable acid, this precipitation being
effected when the liquor is either hot or cold. The colouring matter separates

page_text: sharply from the acid liquor in the form of a flocculent precipitate which when
collected on filters and drained forms a paste suitable for use.
Improvements in the Separation and Purification of Colouring
Matter from Crude Cotton Seed Oil.
We EDGAR SIDDONS WILSON of Arthog, Goddington Road Strood, in the
County of Kent, Chemist, and EBENEZER STEWART of 4 Queen Victoria Street
in the City of London, Merchant, 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 :-
In refining crude cotton seed oil by alkaline solutions, such for example as
caustic soda, or a mono-carbonate of soda, with or without the addition of a soluble
sulphite, a colouring matter is removed from the oil which has not hitherto been
found of much value owing to its admixture with fatty matter and other impurities.
We have found that by suitable treatment impurities can be removed from the
colouring matter, and the latter rendered more suitable for use.
In carrying out our invention we take the alkaline liquor separated from the oil
and containing the said colouring matter and impurities, and treat it by the process
known to chemists as "fractional precipitation" using for this purpose certain
earthy salts such as the chlorides of magnesium or calcium, sulphate of magnesia,
or any of the salts of metallic bases which with the fatty acids removed from the
oil by the said alkaline liquor, produce insoluble or not easily soluble soaps. The
fatty acids, resinous matter, and other impurities are by this means wholly or partly
got rid of, and to the residual liquor which contains the colouring matter, is added
hydrochloric or sulphuric acid, or any acid which will combine with the alkali or
decompose alkaline carbonate, or soluble sulphite, and precipitate the said colouring
matter. The colouring matter precipitated as a flocculent precipitate is collected
for use preferably in a pasty condition.
As an example of the application of our invention, we give the following:-
Two thousand two hundred gallons of crude cotton seed oil are agitated in a
suitable tank with six hundred gallons of a solution of soda crystals containing from
one quarter to one half a pound of crystals to the gallon. We have found that
the colouring matter undergoes deterioration during this process if the temperature
is allowed to reach the boiling point (212° Fabrenheit) and we therefore prefer to
use a refining solution of the above or other convenient strength at a temperature
of about 120° to 130° F. After the oil and alkaline liquor have been kept in
agitation for the time necessary to remove the colouring matter, the contents of the
tank are allowed to separate by subsidence or are made to separate by any known
methods, and the liquor which is of a deep brown colour is drawn of. The brown
liquor is then mixed with a solution of magnesium or calcium chloride so that from
one half to one part, by weight, of the salt is added to one hundred parts by weight
of the liquor. The mixture of liquor and salt solution is then raised to the boiling
point and kept boiling till the separation of the dark insoluble, or not easily soluble,
mixture of soap and other impurities is complete. The hot liquor which now
contains the improved colouring matter is then allowed to remain at rest and is
drawn off, or if necessary filtered or separated by any known method from the
impure soap. The purified colouring matter is precipitated by dilute hydrochloric
!
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page_text: or sulphuric or any suitable acid, this precipitation being effected when the liquor
is either hot or cold. The colouring matter separates sharply from the acid liquor
in the form of a flocculent precipitate which when collected on filters and drained,
forms a paste suitable for use in dyeing, printing and the like.
We do not limit our method by using only a solution of soda crystals as set
forth in the above example, as any other weak alkaline or alkaline-carbonate
solution may be used to extract the colouring matter from the oil. Neither do we
limit ourselves to the exact quantity of the magnesium chloride or other salt above
specified, as this quantity may have to be varied according to the quality of the
cotton seed oil at different seasons of the year.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed, we declare that what.
we claim is:-
First. The purification of the colouring matter extracted by alkalies or alkaline-
carbonates (with or without the addition of a soluble sulphite) from crude cotton
seed oil, by fractional precipitation of the solution containing such colouring
matter by means of magnesium or calcium chloride or other salts which give
insoluble soaps with the fatty acids and resinous or other impurities present in the
liquor substantially as set forth.
Second. The precipitation of the colouring matter thus purified by means of
dilute hydrochloric, sulphuric, or other suitable acid.
Third. The preparation and isolation of the pure colouring matter in the form
of a paste suitable for use in dyeing and printing substantially as set forth.
Dated the 19th day of Sentember 1896.
W. B. JOHNSON,
Agent.