IMPROVEMENTS IN THE PROCESS OF BLEACHING VEGETABLE AND ANIMAL MATTERS WHICH INVENTION IS APPLICABLE FOR DISINFECTING AND SIMILAR PURPOSES
Year: 1882

page_text: PROVISIONAL SPECIFICATION left by Emil Jacobsen and Richard Jacobsen
at the Office of the Commissioners of Patents on the 11th April 1882.
EMIL JACOBSEN, Doctor of Philosophy, and RICHARD JACOBSEN, chemists of
Berlin, German Empire "IMPROVEMENTS IN THE PROCESS OF BLEACHING
VEGETABLE AND ANIMAL MATTERS WHICH INVENTION IS APPLICABLE FOR
DISINFECTING AND SIMILAR PURPOSES
"
The use of peroxide of hydrogen or oxygenated water for bleaching purposes has
hitherto been found difficult on account of its being liable to decomposition, or to
an escape of its oxygen under certain conditions, and of its being affected by transport.
The object of the present invention is to substitute for the peroxide of liydrogen, in
the inajority of cases, baths which are obtained by mixing the solutions of certain
salts with peroxide of barium
As "Schöne" has already discovered, peroxide of barium, when kept under water,
undergoes a very slow decomposition, oxygen being evolved. In the present
invention advantage has been taken of the fact that this decomposition is considerably
hastened by the presence of a variety of salts. The bleaching properties which the
salt solutions thereby assume depend in a high degree upon the nature of the salt,
The best results are obtained by the use of silicates of alkalis, as well as sal ammoniac,
borates of alkalis, and compounds of alkalis with fatty acids; chloride of magnesium,
tartrates of alkalis, phosphate of soda, and the like are less active, and apparently
sulphates produce the weakest results.
For manufacturing purposes bleaching with peroxide of barium and silicates of
alkalis is especially important. The proportions of both, as well as that of the added
water, may vary within wide limits, but a mixture of one part of dry silicate of
soda, one part of peroxide of barium, and one hundred parts of water will be found
effective for the majority of purposes. For the bleaching of vegetable materials,
such as unbleached linen, jute, rags, and paper stuffs, stronger solutions may be used
without danger, but for animal substances a greater proportion of soluble glass or
silicate of soda may be detrimental on account of the free alkali. Sufficiently
diluted silicate solutions however do not attack bair, feathers, silk, ivory and the like.
The bleaching of jute and linen requires from one to two days; that of hair and
feathers a somewhat longer time according to the depth of the colouring. The

page_text: baths can be used over again so long as peroxide of barium can be detected in
the precipitate by means of bichromate of potash and sulphuric acid
The materials to be bleached are prepared for bleaching in the usual manner by
scouring and other operations. It is indifferent, us regards the results of the
bleaching whether peroxide of barium be employed together with a diluted solution
of soluble glass, or a mixture of peroxide of barium and powdered soluble glass be
mixed with water. In many cases it is advantageous to let the materials bleached
with peroxide of barium pass again through weak baths of sulphurous acid, or other
ordinary bleaching agents, in order to decolor or bleach them entirely-When the
nature of the material permits, bleaching with peroxide of barium is more easily
performed in alkaline solutions, as peroxide of hydrogen in alkaline solution
possesses greater bleaching power than in acid or neutral solutions.
For certain purposes, for example, for the bleaching of oil, it is more advantageous
to uso baths completely neutral, such as are obtained, for example, by treating
peroxide of barium with salts of magnesia. Acid salts, for example, bitartrate of
potash, give, with peroxide of barium, less bleaching power. For all the said
purposes peroxide of barium, can with the same results, be replaced by hydrated
peroxide of barium, and also by the dioxides and hydrated dioxides of strontium
and calcium.
The above-named peroxides and hydrated peroxides may be mixed with any
desired metallic salt, and may then be used for disinfecting and perfumery
purposes.