IMPROVEMENTS IN REFINING OR DECOLOURING SOAP MADE FROM COTTON SEED OIL OR [AND] FROM OTHER OIL CONTAINING EXTRACTIVE COLOURING MATTER AND IN VALUABLE PRODUCTS OBTAINED THEREFROM."
Year: 1883

page_text: PROVISIONAL SPECIFICATION left by James Longmore at the Office of
the Commissioners of Patents on the 16th May 1883.
JAMES LONGMORE of Liverpool in the County of Lancaster. " IMPROVEMENTS
IN REFINING OR DECOLOURING SOAP MADE FROM COTTON SEED OIL OR [AND]
FROM OTHER OIL CONTAINING EXTRACTIVE COLOURING MATTER AND IN VALUABLE
PRODUCTS OBTAINED THEREFROM."
In the manufacture of a refined soap from cotton seed oil mucilage or the
residual matter left when refining crude cotton seed oil as described in the
Specification of my letters patent N° 5465 of 1882 I find that a similar process
is equally applicable to the manufacture of soap from retined or crude cotton seed
oil, or other oils containing extractive coloring matters thereby producing a purer
soap than that at present obtainable from those materials. The coloring matter
which is in the oil being recovered and utilized as a dye stuff.
·
My invention consists essentially in adding sufficient caustic alkaline lye to produce
saponification in the usual manner, and in separating the soap so formed by the
further addition of caustic alkali. The lye which contains nearly all the coloring
matter in solution is drawn off, and fresh water added until the soap dissolves or
as it is technically termed " closes," when it is again separated with caustic lye
and the alkali removed the process if necessary is repeated three or four times
until the coloring matter is sufficiently removed.
The lye which contains in solution the coloring matter is separated by settling
and decantation or by filtration.
It will be seen from the foregoing that the ordinary use of salt in separating
soap from its solution is avoided, owing to its lessening the solubility of the
coloring matter in alkaline lyes, thereby materially retarding the operations.
The removal of the coloring matter will be greatly facilitated after the first
operation or at any subsequent stage; the soap is what is technically called
fitted" that is it is dissolved or closed by the addition of water and the head or
fob boiled out, the whole being allowed to remain quiescent for two days when the
usual separation takes place, the excess of alkali together with the coloring matter
being carried down, and is contained in the lower stratum of soap or technically
nigre, which is then removed and can be treated with a fresh batch of soap, the
soap being operated upon as before.

page_text: The strongly dark colored lye when drawn off is filtered, and either super-
saturated with carbonic acid, or neutralized with acetic sulphuric or hydrochloric
acid, or with an alum sulphate or acetate of alumina, or soluble calcium salt such
as chloride of calcium, and the coloring matter precipitated.
The Lake or precipitate formed as the case may be, is collected on a filter washed 5
and dried.
The coloring matter being removed the liquor is freed from any excess of acid
other than carbonic acid, by means of chalk or other form of calcium, and
evaporated till a large quantity of its component salts have crystallized, and
when the remaining mother liquor is added to a fresh batch of liquor and is 1
treated anew.
This process will also be found applicable to other classes of dark soap, or soap
containing a coloring matter.