Improved Bleaching Compound.
Year: 1892

page_text: Date of Application, 22nd July, 1892
Complete Specification Left, 18th Apr., 1893-Accepted, 20th May, 1893
PROVISIONAL SPECIFICATION.
Improved Bleaching Compound.
1 HAMILTON YOUNG CASTNER of 115 Cannon Street in the City of London
Managing Director of the Aluminium Company Limited do hereby declare the
nature of this invention to be as follows:-
While it is generally considered that hydrogen peroxide is a very superior
bleaching agent there are certain disadvantages to its general employment. First,
its high cost compared with other bleaching agents. Second, the difficulty and cost
of transportation, the latter being quite evident when it is considered that the
ordinary solutions (viz., 10 volumes) only contain one and four tenths per cent. of
available oxygen. Third, the solutions gradually decompose and lose their bleaching
power owing to the loss of oxygen. Fourth, it is a well known point that while
hydrogen peroxide solutions must always have an acid reaction which will retard
decomposition in keeping, still the solution used in bleaching must be made alkaline.
Thus to prepare ordinary bleaching baths of hydrogen peroxide requires a certain
amount of chemical knowledge and the frequent testing of the hydrogen peroxide
solutions employed to ascertain its gradually decreasing strength. The preparation
of hydrogen peroxide of good quality from barium peroxide is a matter of some
difficulty, and although it is much simpler to prepare it from sodium peroxide,
where that material is obtainable, still it requires some care owing to the heat
evolved on solution, and in addition care must be employed in handling the pure
sodium peroxide owing to the high percentage of oxygen.
This invention consists of a new bleaching compound prepared in a dry state
and which when simply added to water will without other additions produce a
bleaching bath ready for immediate use in either a hot or cold condition and
adapted for bleaching any materials now bleached by the use of hydrogen
peroxide.
According to my invention the requisite oxygen for the bleaching bath is intro-
duced in the form of sodium peroxide, a material which although long known has
only lately been commercially manufactured under a process invented by me.
Chemists will however know that if sodium peroxide be added to acid solutions the
result will be the formation of hydrogen peroxide and a neutral salt formed by the
combination of the acid with the alkali. They will also know that if certain sub-
stances, say magnesia, be added to hydrogen peroxide, the bleaching power will be
increased, and the baths or solutions may be employed in a warm condition which
will tend to further accelerate the process.
In preparing what I call "Soda Bleach" sodium peroxide is mixed with an
equivalent proportion of a neutral anhydrous salt, such for example as magnesic
sulphate or chloride, or instead of a single salt a mixture may be used, as for
example, magnesium chloride and calcium chloride.
The soda bleach mixture when made in equivalent proportions contains a large
proportion of oxygen, and in closed packages is quite stable.
In preparing this mixture a slight excess of peroxide may be used so that when
a bleaching bath is made by solution it will have an alkaline reaction due to the
free alkali. With this material so compounded it is only necessary to dissolve in
water to form hydrogen peroxide solutions for immediate use, the reaction taking
place on treating with water being as follows:-

page_text: or with calcium the formula would be :-
2
4 MgCl2 + CaCl2 + 5 Na₂O₂ + 15 H₂O = (MgO(HO), 3 Mg(HO)₂) (CaO, 8 H₂O)
+10 NaCl + 3 H₂O₂
Thus owing to the presence of the alkaline earth metal a certain quantity of the
peroxide hydrate is precipitated, which is far more stable when heated than is
hydrogen peroxide, and for materials that naturally are in a degree more difficult
to bleach, the quantity of peroxide hydrate precipitated is increased by increasing
the relative proportion of the calcium salt to the magnesium salt, from the former
a pure peroxide hydrate is precipitated instead of a mixed hydrate and peroxide
hydrate as when magnesia alone is used.
Soda bleach thus made contains at least seven and one half per cent. of available
oxygen, or almost six times the quantity contained in 10 volume hydrogen peroxide,
it is a dry powder which can be packed in tin lined canisters. It does not lose
oxygen in keeping, and it is ready to form alkaline solutions of pure hydrogen
peroxide containing hydrated peroxide of the alkaline earths by merely adding
water.
Such solutions may also be used warm whereby the bleaching action is very
rapid and thorough.
PHILIP M. JUSTICE, Fel. Chart. Inst. P.A.,
55 & 56, Chancery Lane, London, Agent for the Applicant.
COMPLETE SPECIFICATION.
Improved Bleaching Compound.
1 HAMILTON YOUNG CASTNER, formerly of 115 Cannon Street, but now of
13 & 14 Abchurch Lane in the City of London, Managing Director of the
Aluminium Company Limited, 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 :-
While it is generally considered that hydrogen peroxide is a very superior
bleaching agent there are certain disadvantages to its general employment. First,
its high cost compared with other bleaching agents. Second, the difficulty and cost
of transportation, the latter being quite evident when it is considered that the
ordinary solutions (riz., 10 volumes) only contain one and four tenths per cent. of
available oxygen.
Third, the solutions gradually decompose and lose their
bleaching power owing to the loss of oxygen. Fourth, it is a well known point
that while hydrogen peroxide solutions must always have an acid reaction which
will retard decomposition in keeping, still the solution used in bleaching must be
made alkaline. Thus to prepare ordinary bleaching baths of hydrogen peroxide
requires a certain amount of chemical knowledge and the frequent testing of the
hydrogen peroxide solutions employed to ascertain its gradually decreasing strength.
The preparation of hydrogen peroxide of good quality from barium peroxide is a
matter of some difficulty, and although it is much simpler to prepare it from sodium
peroxide, where that material is obtainable, still it requires some care owing to the
heat evolved on solution, and in addition care must be employed in handling the
pure sodium peroxide owing to the high percentage of oxygen.
This invention consists of a new bleaching compound prepared in a dry state and
which when simply added to water will without other additions produce a bleaching
bath ready for immediate use in either a hot or cold condition and adapted for
bleaching any materials now bleached by the use of hydrogen peroxide.
According to my invention the requisite oxygen for the bleaching batli is
introduced in the form of sodium peroxide, a material which although long known
has only lately been commercially manufactured under a process invented by me.

page_text: So + 4 Na₂O₂ + 7 H₂O) = 4 NaSo̟ + (MgO(HO), 3 Mg(HO)) + 3 H₂O₂.
Chemists will however know that if sodium peroxide be added to acid solutions the
result will be the formation of hydrogen peroxide and a neutral salt formed by the
combination of the acid with the alkali. They will also know that if certain
substances, say magnesia, be added to hydrogen peroxide, the bleaching power-will
be increased, and the baths or solutions may be employed in a warm condition which
will tend to further accelerate the process.
In preparing what I call "Soda Bleach," sodium peroxide is mixed with an
equivalent proportion of a neutral anhydrous salt, such for example as magnesic
sulphate or chloride, or instead of a single salt a mixture may be used, as for
example, magnesium chloride and calcium chloride.
The soda bleach mixture when made in equivalent proportions contains a large
proportion of oxygen, and in closed packages is quite stable.
In preparing this mixture a slight excess of peroxide may be used so that when
a bleaching bath is made by solution it will have an alkaline reaction due to the free
alkali. With this material so compounded it is only necessary to dissolve in water
to form hydrogen peroxide solutions for immediate use, the reaction taking place on
treating with water being as follows:-
4 Mgso, +4 Na¸O₂ + 7 H₂O = 4 NaSo̟ + (MgO(HO), 3 Mg(HO),) + 3 H₂O₂.
4
or with calcium the formula would be:-
4 MgCl2 + CaCl2 + 5 Na,O2 + 15 H₂O = (MgO(HO), 3 Mg(HO)₂) (CaO₂ 8 H¸Ö).
+10 NaCl + 3 H₂O₂
Thus owing to the presence of the alkaline earth metal a certain quantity of the
peroxide hydrate is precipitated, which is far more stable when heated than is-
hydrogen peroxide, and for materials that naturally are in a degree more difficult
to bleach, the quantity of peroxide hydrate precipitated is increased by increasing
the relative proportion of the calcium salt to the magnesium salt, from the former
a pure peroxide hydrate is precipitated instead of a mixed hydrate and peroxide
hydrate as when magnesia alone is used.
Soda bleach thus made contains at least seven and one half per cent. of available
oxygen, or almost six times the quantity contained in 10 volume hydrogen peroxide,
it is a dry powder which can be packed in tin lined canisters. It does not lose
oxygen in keeping, and it is ready to form alkaline solutions of pure hydrogen.
peroxide containing hydrated peroxide of the alkaline earths by merely adding
water. Such solutions may also be used warm whereby the bleaching action is
very rapid and thorough.
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed 1 declare that what I
claim is
The new bleaching compound composed of sodium peroxide and one or more
neutral salts of the alkaline earth metals substantially as described.
Dated the 10th don of Amil 1902
PHILIP M. JUSTICE,
55 & 56, Chancery Lane, London,
Chartered Patent Agent for the Applicant.
PHILIP M. JUSTICE,
55 & 56, Chancery Lane, London,
Chartered Patent Agent for the Applicant.